Project Gemini Familiarization Manual Vol2 Sec2

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T

PROJECT l

CONTROL NO. C-160063

GEMINI

SUPPLFMENT

1

!

familiarization manual

¢

-

|-

SEDR 300

COPY NO.

RENDEZVOUSand

/

DOCKING

CONFIGURATIONS THIS PUBLICATION SUPPLEMENTS SEDR300 VOLUME

IMFC I_ O lki lkl E L L THIS DOCUMENT SUPERSEDES DOCUMENT DATED 31 MAY' 1965

_

defense of the United States within the meaning of the Espionage Laws, Title 18, U.S.C., Sections contains 793 and 794, the transmission NOTICE: This material information affecting or therevelation national

_

of which in any manner to an unauthorized person is p_ohibited by law.

.,_J__ .._

DOWNGRADED GROUP-4 AT 3-YEAR INTERVALS; DECLASSIFIED AFTER12 YEARS CONFIDENTIAL

I

I JULY 1966

CONFIDENTIAL

f

GUIDA NCE and CONTROL SYSTEM

TABLE

OF

CONTENTS

TITLE

PAGE

GENERAL ....................................................... ATTITUDE CONTROL AND MANEUVER ELECTRONICS

8-3 8 15

__!_ i:._-:_'_ii_;_ _::::_-_':---_

INERTIAL GUIDANCE SYSTEM ...................... 8-43 iiiiiiiiii:_i!-";_'-..'--_ H ORIZ O N SEN SO R SYSTEM .......................... 8- 201 iiiiiiiiii_i_i!i!iiiiii-_i RENDEZV OU S RADAR SYSTEM .................... 8- 233 iii!iiiii_iiiiiii_iiiiiii ,...°.°°._...,.o.°..°°o.°°. ::::::::::::::::::::::::::: ,..o.....,.°...°°.......,.,

........._.o...°..o,°....o, •°°,°.°o ...o°o.°.°°°°._.o., .°.,.°°°.,..°°....°..,....,

CO MMA N D LIN K.......................................... REN DEZ V O US EVA LUATIO N PO D................ TIME REFERENCESYSTEM ........................... PROPULSION SYSTEM ...................................

8- 273 8- 289 8-3Ol 8- 341

iiiiiiii!!i!iiiii_iiii!!ii iiiiiiiiiiiiiiii'":'i!iiiiiiii !iiiiiiiiiii!iiiiiiiiiiiiii iiiiiiiiiiiiiiiHiiiiiii!ii

i iHi i ! i i i i !i!i i !

........ • ,.. ........... ..°. ., ....... ,.o..** ........ •., .... .......... .........•.,..o....o.. °...... ......... ., ......... • ................. ......... ° ................. ...... ..,. .................

8-1 / 2 CONFIDENTIAL

......... .........

, ................. ° .................

......... .........

° ................. . .................

......... ........... ......... ......... ......... .........

°................. °_ .............. ° ................. ° ................. ................. ,° .................

iii_iiiii_ii!'_iiiiii!_!!

CONFIDENTIAL

__

SEDR300

GUIDANCE AND CONTROL - GENERAL

GENERAL The Guidance and Control System provides the Gemini Spacecraft with the capability to maneuver in space, control its attitude in relation to the earth's surface. and effect a safe re-entry.

It also provides back-up launch vehicle guidance

during ascent and control of certain target vehicle

functions

during rendezvous

procedures.

Spacecraft attitude can be controlled about three axes:

pitch, roll, and yaw.

mode select switch permits selection of either automatic or manual control.

A

An

attitude hand controller, located for use by either pilot, is used for manual attitude control.

Translation control is provided along the longitudinal, vertical, and lateral spacecraft axes. translation

Either of two maneuver hand controllers may be used for manual

control.

No provision is made for automatic

control.

Three types of target vehicles are provided for the rendezvous missions:

the

Agena, the Rendezvous Evaluation Pod (REP), and the Augmented Target Docking Adapter (ATDA)o

Certain functions within the Agena or the ATDA can be controlled

through the Command Link of the Guidance and Control System.

In rendezvous spacecraft, the Guidance and Control System is made up of eight individual systems or subsystems.

They are:

a.

Attitude Control and Maneuver Electronics (ACME)

b.

Inertial Guidance System (IGS)

c.

Horizon Sensors

8-3 CONFIDENTIAL

J

CONFIDENTIAL SEDR 300

z--

BOOSTER SECONDARY AUTOPILOT

DMEASUREMENT INERTIAL UNIT

I

I INERTIAL GUIDANCE SYSTEM •

AUX] LIARY COMPUTER POWER UNIT

lob I POVvER

COMPUTER TURN-ON

| AC-DC

400 CPS POWER

BOOSTER MD_I

J POWER I

SUPPLY



SIGNAL

AC POWER

AC POWER (SELECTOR)

t

z

PO%'ER

MANUAL DATA iNSERTION UNIT

O _ O

POWER CONTROL

PLATFORM (MODE

l

SELECTOR)

_u

CONTROL --

j O

TAPE

;_LRCEI

._J

--

U

MEMORY PROGRAM

PLATFORM

COMPUTER (MODE SELECTOR)

1 • J ;

MODE CONTROL

I

RESOLVER EXCITATION GIMBAL POSITION SIGNAL

ON BOARD C_MPUTER

I I

VELOCITY l

INDICATOR IN CREMENTAL

PLAIEORM

I

DISPLAy GROUP

(INERTIAL) I

ATTITUDE

I

- -1-I| TARGET YA% AND

_ TARGET VEHICLE

SUPPLY POV, _ ER ,

I

ATTITUDE ERROR

PITCH ANGLES

_

ANTEN NA RECED/ER SYSTEM

I

"

-

/-

q

POV, ER SUPPLY

TIME REFERENCE

TRANSMITTER

INTERROGA11ON AND PDAEE INFORMATION

J

I C_MMAND_,N_I_TE'ND'CAT°R LNK I i_NO_NGR I _PTE_°°C_'NG) L & RF COMMAND

soB-B,T DETE_OR I_ Figure

XMIT ANT iNTERROGATION

l

PROGRAMMER

(ANALOG)

r_'E ND'_'_V O-US _ -RADAR J SYSTEM

'

ANTENNA SYSTEM

/TRANSPONDER I

I

_l

I_V INFORMATION

ELECTRONICS

_

I

_,V COMMAND

ENCGDER LINK

j 8-1

Guidance

I

_>

Control

Functional 8-4

CONFIDENTIAL

Block

Diagram

SPACECRAFT

8 THRU

12 ONLY.

[_AGENA AND ATDA TARGET VEHICLES ONLY.

(BEFORE DOCKING)

and

I

(Sheet

1 of 2)

CONFIDENTIAL SEDR 300

._,_.__

PROJECT

I-;O.,ZON SENSO,'--" --

GEMINil

i----" -- -- "

' cPsP°wE ' -i SUPPLY PO_'ER

I

RE-ENTRY ROLL COMMAND

MANEUVER CONTROL ELECTRONICS AND ATTITUDE I_ATE

--

I

_

I

_

ATTITUDE ELECTRONICS

'_

II

GYRO'S

_

t

_

I

I

k

FIRE COMMANDI

1

I

ATTITUDE COMMAND

'

ATTITUDE

(MODE

HAND

ACME

CONTROLLER

PO'C,'ER

(RIGHT)

INVERTER

HAND

AND MANEUVER ORBIT ATTITUDE ELECTRONICS

I

I

I

I

THRUSTERS

I,

__

I

MANEUVER THRUSTERS

L

_I

-!

I

_1 --

m TO BIO-MEDTAPE

RECORDER

TO VOICE TAPE RECORDER

I"_M E REFEI_EN_Y ST--'_ .... TIME DIGITAL CLOCK

1 CORRELATION BUFFER

I

I

DCSEECE,VER> UPOATE I_

8P.P.S.

I

-

ELECTRONIC

TIMING

SIGNAL I

r

TIMER

E.T. & T.T.G.

EVENT TIMER

ACCUTRON CLOCK

GMT CLOCK

I

I

: T X SIGNAL

AND 8.19

KC CLOCK SIGNAL

I TR-256 SEC,TR-30 SEC TR SIGNAL

Figure

8-1

I

ATTITUDE

coMMA.D j

--

E.T.

SEQUENTIAL_LIFT-OFF

CONTRoLRE-ENTRY SYSTEM

MANEUVER

....

INTERROGATION TIME REFERENCE AND

_

I

(DAME) II i

-CONTROLLER HAND (LEFT) MANEUVER

I

I

1

FIRE COMMAND

CONTROL

,EEC, OE)

"

(ACE)

I 400 CPS POWER

1'

:c j

r_TTTT'_I:

I

HEAD SENSOR

ELECTRONICS SEN SOR

I

J

Guidance

DCSRECEIVER

_

SEQUENTIAL SYSTEM

_

and Control

Functional 8-5

CONFIDENTIAL

Block

I

_

RETRO FIRE CIRCUITS

Diagram

(Sheet

2 of 2)

CONFIDENTIAl.

PROJECT

GEMINI m

__

SEDR300

d.

Rendezvous

Radar

e.

Command

f.

Rendezvous

g.

Time Reference

h.

Propulsion

System

Link Evaluation

Pod

System

(REP)

(TRS)

System

SYSTEM FUNCTIONS

The various functional

Attitude

guidance

and control

relationship

Control

The Attitude

between

and Maneuver

Control

systems each

firing

com,_nds

provided

by the attitude

of the systems

related.

is illustrated

The

in Figure

8-1.

Electronics

and M/_euver

thruster

are all functionally

Electronics

for the Propulsion hand controller,

system System.

converts Input

input

signals

signals

to

to ACME are

the IGS, or the horizon

sensors

depend-

ing on the mode of operation.

Inertial

Guidance

The Inertial mation, ation

System

Guidance

guidance

information

manual

provides

computations_

inertial

and displays.

is used for computations

are used for back-up Displays

System

are utilized

ascent

guidance,

attitude

The inertial

and display

rendezvous

by the crew for reference

control.

8-6 CONFIDENTIAL.

and acceleration attitude

purposes.

guidance

and acceler-

Computations

and re-entry

information

infor-

guidance.

and as a basis

for

_-

CONFIDENTIAL

EQ_

PROJE

=

Horlzon Sensors

The Horizon Pitch

Sensors

and roll

error

and to the

IGS for

Rendezvous

Radar

The Rendezvous Target

provide signals

are

platform

Radar

information

a reference supplied

earth

local

vertical

to ACMEfor automatic

during

attitude

orbit. control

alignment.

provides is used

to the

for

target

range,

rendezvous

range

rate,

computations

and angle and for

information.

display

A radar indicator displays target range and range-rate information.

purposes. Target eleva-

tion and yaw angles are selectable for display on the attitude indicator.

Comana TInk The Command Link provides a control capability over the Agena or ATDA target vehicle.

Coded cu.-,_ands, transmitted either through the radar or the umbilical,

allow the pilot to activate or de-actlvate the various

systems of the target

vehicle.

_e_dezvous

Evaluation

The Rendezvous

Pod

Evaluation

Pod is the target for a simulated rendezvous mission.

The pod is carried into orbit in the equipment adapter section of Gemini. in orbit, the pod is ejected and its systems activated.

Once

A radar transponder and

acquisition lights in the pod allow the Gemini pilots to perform rendezvous exerclses.

8-7 CONFIDINTIAL

CONFIDENTIAL

PROJECT __

GEMINI

SEDR300

Time Reference

System

The Time Reference functions. form.

System provides a time base for all guidance and control

Time is displayed for pilot reference in both clock and digital

The TRS also provides timing signals to the computer and the Sequential

System.

Propulsion

System

The Propulsion Thrusters

System provides the thrust required

are provided for both translational

co, hands for the Propulsion

for spacecraft

maneuvers.

and attitude control.

Firing

System are provided by AC_ME.

GUIDANCE ANDCONTROL MISSION

The functions of the Guidance

....

and Control System are dependent on mission phase.

The mission is divided into five phases for explanation purposes. are:

pre-launch,

launch, orbit, retrograde,

The phases

and re-entry.

Pre -launch Phase

Pre-launch

phase is utilized for check-out and programming

control systems.

Parameters

inserted in the computer. desired launch azimuth. selectors

of guidance and

required for insertion in the desired orbit are

The IMU is aligned to the local vertical and the Power is turned on to the various systems, and mode

are placed in their launch position.

Check-out and parameter

are performed in the last 150 m_nutes prior to launch.

8-8 CONI=IDI[NTIAL

insertlo:

CONFIDENTIAL

_;

PROJECT SEDR

___.

TRACKING

300

GEMIN!

__

DATA =.]

TELEMETRY

GROUND CONTROL

G/E BURROUGHS SELF CHECKS Vl

GEMINI CREW

DISPLAYS I

MANUAL SWITCHOVER

TITAN

CREW STATION SYSTEM ASCENT ;EMINI

9

PRIMARy BACK-UP

_|

J

GUIDANCE

I

1

J

RATE GYROS

J

I MALFUNCTIO N DETECTION SYSTEM

J

AUTOMATLC

J

SWiTC HOVER

ANGLE SENSORS I

ASCENT GUIDANCE SWlTCHOVER

GIMBAL

i

GEMINI

TRANSMITTER

RECEIVER

:[ :

O.B.C.

FI L I I

TITAN

I

I --

COMPUTERS A-I r J-1 BURROUGHS

.....

_

(PRE-LAUNCH) }

TARGET

AUTOPILOT

DATA

_

I

TI

;

1

BACK-UP

'

MOD III TRACKER

HYDRAULICS

TRACKING DATA

: MISTRAM

2rid STAGE

2

ENGINES

I'<_

NOTE STAGE _>

"

_

--

GODDARD

SPACECRAFT 6 AND 8 THRU 12 ONLY

! "mid

I I TRACKING SYSTEM

ENGINES

BACK-UP ASCENT GUIDANCE

Figure

8-2

Gemini

BACKzUP HYDRAULICS

Ascent 8-9

CONFIDENTIAL

Guidance

(Back-Up)

CONFIDENTIAL

PROJECT __

GEMINI

SEDR300

Launch Phase

Guidance and control from lift-off through SSECO is provided by the booster guidance system. control.

However, in case of booster guidance malfunction the IGS can assume Provision

(Gemini) guidance.

is made for either automatic or manual switchover to back-up Figure 8-2 indicates both methods of s_itchover and the back-

up method of controlling and acceleration information remaining

the booster during ascent.

parameters throughout

Is used to continuously

the launch phase.

use the Propulsion

is displayed.

System to increase

required for insertion in the desired orbit. approxlm_tely

Ground tracking

update computer parameters.

velocity required for insertion

after separation,

The IGS monitors attitude

At SSECO, the

The command pilot will, spacecraft velocity as

Insertion will take place

580 miles down range at an inertial velocity of approximately

25,YTO feet per second.

Orbit Phase

Orbit phase is utilized for checkout and alignment maneuvers

and preparation

of systems, rendezvous

for retrograde and re-entry.

Immediately

after

insertion a series of system checks will be performed to assure the capability of guidance and control systems.

Guidance

computations

for accuracy against ground tracking information. aligned by ground command or by the pilot.

and measurements

are checked

Systems are updated and

After completion of system

=hecks, the catch-up and rendezvous maneuvers

can be performed.

During the final

orbit, guidance and control systems are re-allgned in preparation for retrograde and re-entry.

8-IO CONIFIDRN'rlAL

CONFIOIENTIAL S|DIt300

Retrograde

Phase

Retrograde

phase begins

is placed

in re-entry

approximately

mode

and begins

The Time Reference

System provides

and TR.

At TR-256

seconds,

needle.

The Propulsion

re-entry

control.

Retrograde changes

are

Re-Entry

Phase

Re-entry

phase

through

heads

are

held

until

the

CMD.

flight c_nds.

Shortly

attitude

computer

re-entry

control.

For automatic

control,

controls

of touchdown

from orbit

is referenced

The computer computations.

seconds,

TR-30

seconds,

on the pitch

attitude manually !

attitude

and maneuver during

by the IGS, and

retrograde

adapter

retrograde,

to

retrograde.

velocity

orients Re-entry

starts_ and the pilot

the RE-ENT mode

Is utilized.

roll attitude. computer

and

8-11 CONIFIDINTIAL,

attitude _00,000

a choice

selects

mode

indicates program

spaceis

feet of

RE-ENT

EATE

In the automatic

For either

re-entry

heating.

the pilot

has

during

scanner

the

At approximately

control,

counts

and horizon

the pilot

starts.

timer

sixty minutes

180 ° roll, 0° yaw).

For manual

re-entry

event

down from

program

to the

The

counting

of the computer

and to control

retrofire.

program

spacecraft

The purposes

the

after

re-entry

computer

director

re-entry

at TR-256

are monitored

after

(0 ° pitch,

or automatic

the computer

data for

is controlled

and will be

retrofire,

Jettisoned.

altltl,de, the manual

immediately

After

craft to re-entry

retrofire.

for reference.

begins

phase_

attitude

and attitude

zero at retrograde

re-entry

before

16 degree bias is placed

is switched

Spacecraft

displayed

collecting

indications

a minus

System

acceleration

five minutes

of control,

computed

the

attitude

are to control

By controlling

mode,

the point

the spacecraft

CONFIDENTIAL

PROJECT S_

_@_

G s,oR 300 EMINI

roll attitude and rate, it is possible to change the down-range touchdow,,point by approximately right.

500 miles and the cross-range touchdown

by 40 miles left or

The relationship between roll attitude or rate and direction of lift is

illustrated

in Figure 8-3.

and ends at 90,000 feet. cow,ands an attitude

The roll control starts at approximately

400,000 feet

Re-entry phase ends at 80,000 feet when the computer

suitable for drogue

chute deployment.

8-13/l_. CONFIDENTIAL

CONFIDENTIAL

ATTITUDE CONTROL AND MANEUVERING

ELECTRONICS

TABLE OF CONTENTS TITLE

_

PAGE

SYSTEM DESCRIPTION ......... SYSTEM OPERATION...... ...... GENERAL, , .... FUNCTIONAL OPERATION _ACME)_ , . MODE OPERATION ...... , . . SYSTEM UNITS..... , . . . ATTITUDE CONTROL ELECTRONICS(ACE). ORBIT ATTITUDE AND MANEUVER ELECTRONICS (OAME) . . . . . . , RATE GYRO PACKAGE (RGP) . . , • • POWER INVERTER PACKAGE , ......

8-15 CONFIDENTIAL

, , 8-17 8-17 8-17 . . 8-18 . . 8"21 • 8-30 Z 8-30 . . 8-38 • • 8-39 8-_2

CONFIDENTIAL SEDR 300

_-_-.

ACME BIAS POWER ROLL JETS ACME LOGIC (3) ATT. DRIVERS ACME CONTROL (2) MANEUVER THRUSTERS(8)' ATTITUDE THRUSTERS(8) RCSA THRUSTERS(3) OVERHEAD CONTROLS _ RCS B THRUSTERS(3)

NEUVER

.-

L_

\"--...L_ \- POWER SW,TCHES

',

_ CONTROLLER

CONTROLLER ATTITUDE HAND

i_

ATTITUDE CONTROL

\\

MODE SELECTOR ATTITUDE CONTROL

_--

\\

,

/

INVERTER

ATTITUDE CONTROL

_

/'-_

I ELECTRONICS PACKAGE

_.

TTITUDE AND

RATE GYRO PACKAGES

%

PACKAGEMANEUVER ELECTRONICS

Figure

8-4

Attitude

""

Control

and

8-16 CONFIDENTIAL

Maneuver

Electronics

/

'7

,

CONFIDENTIALSEDR 300

PRO ACME

SYSTEM

DESCRIPTION

The Attitude

Control

and Maneuver

the control

circuitry

to attain

velocity. horizon

The ACME accepts sensors,

firing

command

composed

platform,

of four

cal rate stalled

and Maneuver

in the equipment

the

solenoid

8-4) provides attitude

and applies

valves.

Electronics

a power

inverter

ACME

is

and two identi-

The O_ME package

Total weightof

s

(ACE),

and rate gyro packages

module.

or

controller,

Control

inverter

bay of the re-entry

capability

selectable

or the computer hand

attitude

control.

solenoid

valves

SYSTEM

(OAME),

hand

the signal(s);

System

Attitude

of the adapter.

spacecraft

from the attitude

Propulsion

Electronics

(Figure

are in-

is located

the ACME System

is

40 pounds.

separate,

The attitude

a desired

processes

The ACE, power

section

The ACME provides

platform

inputs

suosystems:

Kyro packages.

approximately

signal

(ACME) System

maintain

or computer;

separate

in the center

Electronics

and/or

to the appropriate

Orbit Attitude

seven

SYSTEM

of automatic

modes provide

controller

of operation. the

reference

provides

The maneuver

for translational

or manual

the input

hand

controller

attitude

control,

The horizon

sensor,

for automatic

modes

signals

for manual

supplies

signals

with

the inertial of operation. modes

of

to the maneuver

maneuvers.

OPERATION

GENERAL The ACME provides

attitude

of the spacecraft

mission.

attitude

rates.

Signal

commands

for the Prc_Isic_

control,

automatic

Rate gyro

inputs

inputs

are modified

System.

8-17 CONFIDENTIAl.

or manual,

during

to ACE are used by ACME

logic

all flight

to dampen

and converted

phases

spacecraft to firing

CONFIDENTIAL

PRiNI __

SEDR300

The ACME functional pulse,

re-entry

different routing

rate co_and,

signal input

to Re-entry

modes

of control

modes

(horizon

from control utilized.

comms_ds mental

are separated

direct,

panel

ACME power

Control

ACME

by guidance

the control

and attitude redundant

attitude control

Display

control

and control

rate

switches control

increments

mode,

control modes

modes

are

subsystems and roll

(from the incre-

(from the radar necessary

The

information

rates, bank angle

velocity

and range

by ACE for drivers.

attitude

when manual

a

indicator).

for selection

along with

of

selection

options.

(AC_) (Figure

8-5)

signals

and attitude commauds.

group),

and range

and logic circuits

COW,hands or error

firing

display

valve

automatic

command).

attitude

direct,

Each mode provides

and manual

is supplied attitude,

also contain

for the various

types;

rate

rate co_nand,

to be processed

is used as reference

information

indicator),

FOWC_ONALO_ON Attitude

and platform)

indicators

scan,

(RCS) or OAME solenoid

pulse and re-entry

(from the attitude

The control panels

of inputs)

into two basic

of the following:

velocity

switches

System

are horizon and platform.

(or combination

Control

Reference

and consists

re-entry,

scan, re-entry

(rate commaud,

gyros

modes of the control

from the computer,

hand controllers The firing

are converted

commands

to the RCS or the Orbit Attitude

platform,

horizon

System

rate

by the ACE into thruster

are routed by a valve

Maneuver

sensors,

driver

(OAMS) attitude

select system

solenoid

valve

drivers. Signal

inputs

signals,

to the ACE are of three

and ac attitude

rate

by ACE mode logic switching the proportional

circuitry

signals.

circuits. which

types : These

ac attitude

signals,

dc attitude

signals

selected

and distributed

Selected

amplifies,

are

signals are channeled

sums and demodulates

8-18 CONFIDENTIAL

through

the signal

inputs

....

CONFIDENTIAL

PROJECT

GEMINI SPACECRAFT

INVERTER

CONTROL MODE

BIAS

JAC II SW,TCH

PC

_

POWER

LI OCPOW,R

C POWER

SPACECRA

I

RING

"A"

VALVE DRIVERS ANE_

T ACME INVERIER

ATTITUDE POWER SOLENOID VALVES

J

SPIK_ SUPPRESSION

(REF)

THEUSIER RCS DIRECT TO

COMMANDS FIRING BIAS

J

RCS RING AANDB-"7 SOLENOID VALVES j

I

J !

DIRECTION

THRUSTER FIRING COMMANDS

STEERING ATTITUDE

PULSE/DIRECT

SWITCH PULSE

HAND CONTROLLER

j

INITIATE SWITCH

BIAS

SIGNALS

_

J

THRUSTER

--|PULSE

L,-

7Z .,:ZEM;:TNORr

PICK OFF

J

J

I

I

I

L

SIGNALS

AND

SPIKE

SUPPRESSION

FIRING COMMANDS

MANEUVER SPIKE SUPPRESSION

|

I I | i J

RING "B" VALVE DRIVERS

DC POWER

_-_

I OAME ATTITUDE VALVE DRIVERS

l

J

OAME

J

ANO SPIKE SUPPRESSION

HORIZON

PITCH & ROLL ATTITUDE

SENSOR

SIGNALS

l

8BMj _BM

HORIZON

J

T

oAC

POWER

R, rE r RO

RATE SIGNALS

I 0F C F

RATE SIGNALS SIGNALS

I

",_Y,"_',,c_-_'_ ] P

P

SPACECRAFT DC POWER

SENSOR SIGNALS AC POWER

r_

=

RE-ENTRY ATTITUDE RING"B"

ATT,TOOES,GNALS _ C,RCDITR_ _:

RATE DC COMMAND POWER

_=

_

SPACECRAFT

RATE SIGNALS TO

HAND CONTROLLER L/H MANEUVER

STSER,NGD'R SWITCHES

POWER

DISPLAY

I

:

_IAS

I

o_s VALVES

i_

_

J

--GSE

TORQUER INPUT

JJ

PROPORTIONAL

ATTITUDE ERROR SIGNALS

(KEF)

(PITCH, ROLL, YAW)

,

i 1

"

STEER/NO

R/H SWITCHES MANEUVER HAND

I

I

I I DIGITAL COMPUTER (REF)

(REF)

I

I

INERTIAL plATFORM

SOLENOID

ROLL ATTITUDE ERROR SIGNAL I

i •

IL_ Figure

i

I

8-5

ACE ACME

Functional 8-19

CONFIDENTIAL

Block

Diagram

CONImlDINTIAL

PROJECT

into adc ac prior

analog

output.

to entering

converted

by

discrete,

the output

c_ds.

torque

suppression

circuits

limit the voltages

generated

thruster

select

across

Zener

firing

system to the valve

diode

drivers

spike

the solenoid

valves

Controller

attitude

signals,

upon the control handle

may be manually reference.

(plus a hand mode

movements

controller

and/or pulse

signals

are produced

or deadband.

a calibrated

position

Output

of control

before

on time. another

outputs

signals

signals

The control

control mode may be found in the MODE

Rate

signals

controller

handle

or

produced

are

deadband.

generator

must be returned

can be commanded.

OPERATION

depending

is displaced

a pulse

con-

or direct

by positive

from a center

trigger

hand

to telemetry)

are produced

position.

the hand

single pulse

are rate, pulse

output

displacement

when

Pulse

by use of the attitude

position

from the centered

to the amount

threshold

controlled

Controller

selection.

proportional

neutral

valves.

are then

interruptions.

comm_nd

to produce

driver

to

or negative

or to the OAMS attitude

thruster

and a visual

preset

signals

or negative

from the valve

drivers,

are converted

to a positive

of either positive

are routed

signals

The analog

switch circuitry

ring B) valve

troller

negative

_rcuitry.

to the appropriate

Hand

Spacecraft

(dc attitude)

command

current

Attitude

logic

consisting

These commands

for a firing

sensor

the proportional

control

RCS (ring A and/or

during

Horizon

GEMINI

Direct

past

a

in ACE to a

Details

of each

paragraph.

RCS Direct _le RCS direct mode RCS thrusters,

is selectable

and by-passes

RING A or RING B switches

as an alternate

the ACE.

provides

means

of manually

The DIRECT position

a circuit

8-20

the

of each of the RCS

ground to 12 attitude

OONFIDESNTIAL.

firing

hand

con-

CONFIDENTIAL

PRNI [_

SEDR300 The ground is then applied directly to the

troller RCS direct switches.

required thruster solenoid valves through appropriate hand controller displacements.

This RCS mode of operation is intended for backup or emergency control

only •

Ns_euver

Hand Controllers

Tra_-lational maneuvers of the spacecraft in the horizontal, longitudinal and vertical planes may be c_nded

by either of the maneuver hand controllers.

Displacement of a hand controller, fr_n the centered or neutral position in any of the six translational directions produces a direct-on c.-,-_ndto the respective solenoid valves.

Rate Gyros The function of the rate _ro yaw and roll

axes

of the

that sensed rate.

package is to sense angular rate about the pitch,

spacecraft

and provide

an o_tput

signal

proportional

to

Selection of certain control modes provides gyro inputs to ACE

for angular rate damping.

Additional information concerning the rate gyros may be

found in the paragraph under SYST_

U_TS

RATE GYR0 PAC_%GE.

Power Inverter The power inverter provides the ACME and horizon sensors with ac power. craft primary

dc power is source

Measuresent may be found

converted

to

26V,

of ac excitation).

_it in

(IMU) is the

off.

paragraph

400

cps

(The IGS !inverter provides the i The ACE inverter is utilized when the Inertial

Additional under

Space-

SYST_

information

regarding

the

power

inverter

UNITS POWERINVERTER PACI_GE.

MC_E OPERATIO_ _trol

of spacecraft attitude is acconplished through the selection of seven

8-21 CONFIDENTIAL.

CONFIDENTIAL

PMINI _.

SEDR300

functional

control

or type of AC_ mode

provides

signals

circuits

serve power.

Each

operation either

ing of input all unused

modes.

relays at the power

mode

in conjunction

automatic to ACE. within

Switching

control

level.

with various

or manual

spacecraft

In addition,

for a specific

mission

control

the mode

the ACE during

is performed

is utilized

logic

through

circuits

use of the horizon

by transistors

The operation

phases.

of each control

Each

the switchde-energlze

scan mode

at the signal mode

purpose

to con-

level

and by

is explained

in

the following.

Direct

Mode

(MII

In this mode, attitude direct voltage

solenoid switches

firing

valve

(Figure 8-6).

a circuit

switches.

Six normally-open

commands

drivers

to a transistor

completes direct

thruster

by actuation Selection

designated

The transistor

to the RCS or OAME

of the attitude

switch

is common

remains

contacts

directly

of the direct

ground

to ground which

switch

are applied

A.

hand

controller

mode applies

Conduction

a bias

of the transistor

to one side of the hand

on as long as the direct mode

provide

the command

signals

controller

is moved

threshold

Deflection

in the desired

applies

a ground

direction

which,

travel.

from switch A directly in turn,

as long as the hand This mode

of handle

fires

controller

of operation

to the valve

the proper is displaced

is optional

beyond

beyond

driver relative

thruster(s).

Thrusters

the _.5

is selected.

in the pitch,

and roll axes and will close when the hand (2.5 degrees)

controller

degree

a preset direction to that

continue threshold.

at all times.

P se In this mode,

the attitude

commands

initiated

8-22 @ONPIOIIN'rlAI.

by hand

controller

yaw

displacement

firing

CONFIDENTIAL

__j-

I

__

SEDR300 PROJECT GEMINI r

__

_

"1

I=_

i= °-

I OPo>

O>

°-

-

i

LL-_2TL_, ...... I I _

...... -T-t

II

-' 0

=

I

I

° <_]

0

=' >=u= '-" _>

I

_

==

ID

,.__ ,.=.

o_z

u_>

:_Zo

t

_OS_z z_ or_ _

I o__o

I _7"{

....

I I _ __ o I _ I

I I_, I I I

I I

_ 2 _

I

I I

,-, ,_

I I

;.

I;-;..........

L .11 / _=s i_, 4 ,& 4 & & /_

_

I=

Figure

8-6

ACME

I ]

Simplified

Block

Diagram

8-23 CONFIDENTIAL

(Direct

& Pulse

Command

Modes)

CONFIDENTIAL

PROJECT

GEMINI

$EDI 30O

fire a single pulse generator in the ACE (Figure 8-6). activates the generator, command is received.

The pulse mode logic

allowing it to fire for a fixed duration when a pulse

Commands originate every time one of the six normally-

open pulse switch contacts of the hand controller is closed. the generator

This triggers

and applies a bias voltage pulse for a 20 millisecond

to ground switch A.

This ground is then applied to the RCS or 0A_

valve drivers, through the actuated hand controller for thruster firing.

direct switches,

duration attitude as a command

Commands may be initiated in the pitch, yaw or roll axis

by moving the control handle in the desired direction beyond a preset threshold (3.5 degrees).

Thrusters fire for 20milliseconds

placed beyond S.5 degrees.

each time the handle is dis-

This mode is optional at all times and will normally

be usedduring platform alignment.

Rate Com-_nd Mode (MB) In this mode, spacecraft attitude rate about each axis is proportional attitude hand controller

displacement

from the neutral deadband

(The output remains at zero for displacements providing

a non-operational

handle displacements,

area or deadband).

less than I degree of handle travel, Command signals, generated by

thruster firing occurs.

in the hand controller

handle displacement.

(Figure 8-7)

are compared with rate gyro outputs, and when the difference

exceeds the damping deadband, potentiometers

to the

Signals originate

from

and outputs are directly proportional

to

A maximum command signal to ACE produces an angular rate

of i0 degrees/second about the pitch and yaw axis and 15 degrees/second about the roll axis.

Automatic, closed-loop stabilization of spacecraft rates is provided by the sensing of angular rates by the rate gyro package.

8-24 CONFIOENTIAL

With the absence of hand

CONFIDENTIAL SEDIt 300

controller within

command

signals,

+ 0.2 degrees/second

degrees/second

control. until

about

control

Output

dampened

and to wlthin

signals

the rate signal

at all times

or attitude

each axis are

_ 0.5

from the rate gyros

is within

and will

to

normally

the damping

be used

during

changes.

Scan Mode (M4)

processed

during

to within

orbit

_5 degrees

maintained null.

the pitch

sensor

firing

repetition

pitch

is also

command.

deadband.

available

is summed with

control

deadband,

The pulse

without

having

within

attitude

a desired

is maintained

mode.

to supplement

sensor

upon how much

Pulse

control

control.

(pitch

or roll) logic

is a

and the pulse

the attitude

to use the power-consumlng

about

to the ACE to maintain

of the ACE on-off

in this mode provides

zero degree

the automatic

input

is

from the attitude

the attlt!ude error

the output

automatically

and roll attitude

by commands

time is 18 milliseconds

is dependent

A lag network

are

of thehorlzon

the pitch

When

(pitch and roll)

-5 degree!output,

as in the pulse

down orientation.

frequency

rate damping

attitude

+5 degrees

in the same manner

the 5 degree

i

of the horizon to withln

outputs

the spacecraft

Pitch

bias voltage

the 5 degree

and hold

sensor

8-8).

and roll axes

A -5 degree

Re-entry i

(Figure

horizon

about the yaw axis is accomplished

controller

degree

mode,

automatically

Control

exceeds

command

by the ACE to orient

deadband

pulse

attitude

is optional

thrusting

In this automatic

hand

with OAME

fire commands

This mode

translational

Horizon

rates

with RCS attitude

are used to produce deadband.

spacecraft

error

a pseudo

exceeds

the 5

rate feedback

for

rate gyros.

Mode (M_)

In this automatic

co_m_nd

mode,

spacecraft

angular

8"25 OONFIDBNT|AL,

rates

about

the pitch

and yaw

CONFIDENTIAL SEDR 300

.I -_.

i

1

IL.

Ze_

i

uJ

O_

2=

='_"

°_o>

r

r-

,

I I I

u

o>

I

-3

Ii iL_ I ,

_@_

I

II0-0 I

i o@ I _@ I

li

a

l---1

I

_-_

" =_ Oo_oO

z

m_

_

I

_

_

_g:

L

_I

I

/\_

_

_

Z

o_

O_

zo__

_

_

a gg_

m_

O

.,x. Figure

8-7

ACME

Simplified

Block

Diagram

(Rate 8-26

CONFIDENTIAL

Cmd.

and

Re-entry

Rate

Cmd.

Modes)

Figure

8-8

ACME

Simplified

Block

Diagram

8-27 CONFIDENTIAL

(Horizon

Scan

Mode)

CONFIDENTIAL

Z axes are _ampened

to within

about the roll axis de&Tees

(Figure

of the attitude

computer

a fixed roll rate comm_nd

provided

to minimize

Mode

command

from the attitude

depending

re-entry

The computer

control

a reference

spacecraft

point.

With

rate damping

the spacecraft

for initiating

a bank

rates

to the rate command

Angular

cally

computer

input

a_le

Roll

to within

+2

to ACE.

The

attitude between

command

or

the predicted

to yaw crosseoupling

is

lift vector.

controller.

crosscoupling. mode.

controlled

upon the relationship

touchdown

+2 degrees/second

(M_)

mode,

hand

is identical

of either

the spacecraft

Command

In this manual

Roll attitude is

consists

point and the desired

Re-entry/Rate

method

8-9).

and to within

colmnanded by the digital

roll input to A_E

touchdown

+4 degrees/second

bank

the exception mode

about

angle

are controlled

of wider

with the addition

the three

re-entry

on the control

roll

deadbands,

the

of roll-yaw

rate

axes is identical

and roll rate commands

but are provided

manual

by rate commands

to the

do not automati-

panel

displays

as

commands.

Platfo(M61 This attitude axes, with matically

control

respect

mode

is used to maintain

to the inertial

to within * I.i degrees

tude,

with respect

to the earth,

orbit

rate or alignment

+ 0.5 degrees/second.

matically

hold

an inertial

spacecraft

can be held

during

attitude

attitude.

Spacecraft purpose

attitude. fine

attitude,

if the inertial

The primary

spacecraft

attitude

Spacecraft

of the platform

mode of operation.

to within

maintaining

platform.

spacecraft

alignment

8-10). 8 -28 CONF_DEN'T'JAL

is held

auto-

A horizontal

atti-

platform

attitude

rates

of this mode

This mode

in all three

is in the are dampened

is to auto-

is also useful

of the platform

for

(Figure

CONFIDENTIAL

a>

i

I

.J

i

oQo

z

[

_

N o _

u

,N o

_

J

/\

/

L__ Figure

8-9

ACME

Simplified

Block

8-29 CONFIDENTIAL

Diagram

/\

/\

;

]

(Re-entry

Mode)

CONFIDENTIAL

PROMINI SEDR300

- ACME/RCS

Aborts

The rate

command

abort modes. abort

mode of ACME will be utilized

Control

CONTROL

The ACE package

ELECTRONICS (Figure

cover and contains logic circuitry processing

(+20, +I0, perform

signal

inputs

solenoid

three

for a mode 2

sequential

relays.

module

boards.

axis

logic boards,

driver

These

processing

firing

for the RCS

boards,

These

an

ac signal

a powe_

replaceable

control,

commands.

solenoid

make up the ACE

logic board,

relay

board.

has a removable

boards

for the three-axis

thruster

circuits

a mode

three

-I0 vde) and a lag network

17 pounds,

module

and

They also

supply

convert contain

the

valves.

Operation

signals

A functional

to ACE

represented control

are dependent

schematic

ing to thai mode.

transistor

switching

input

Additional

signal

ACE mode logic

on mode

8-30

logic

to are

of an atti-

circuits

is then switches

may be found in the Mode Logic bwltchingpsragraph.

CONFIDENTIAL

circuits

The selection

in the logic

information

rate correction.

8-11 and is sectioned

at the left of the figure.

The appropriate

for processing.

axes.

rate requirements

or attitude

in Figure

for each of the three

initiates

or attitude

an attitude

of the ACE is shown

by the blocks mode

upon altitude

and are used to obtain

show signal processing

channel

approximately

of the following:

into appropriate

of the spacecraft

ACE

all

(ACE)

ten removable

the signal

valve

Functional

tude

to ACME by the abort

8-4) weighs

and consist

board,

boards

Input

switched

during

UNITS

ATTITUDE

board

control

over the RCS ring A and ring B switches

is automatically

SYSTEM

for attitude

pertain-

into the proper switching

CONFIDENTIAL SEDR 300

..,<:_..

PROJECT

GEMINI I

--

--

'

I=_1 = =_I =_'-='=> I°_1"-

I, o I r ---1 I _ < I I i _ I

I

I

..... I_

]

I I

_..z.>.

I_ o>o 1 I ' --

f .......

" I

I

_ I °

I I

II_

L___

_l

I

z U

_

l -

oo-

_

ul.-

___._ )_..__

1 /\

z_

Figure 8-10 ACME Simplified Block Diagram (Platform Mode) 8-31 CONFIDENTIAL

I J

CONFIDENTIAL

PROJGEMINI __.@

SEDR300

Proportional switch

circuits

amplifiers

consist

The outputs

put of the switch

amplifier

verted

to a positive

either

the positive

torque

logic section.

a minimL_ signals

are chopped

The valve

driver

low-hysteresis

The switches

select

circuits

control

valve drivers.

drivers

Transistor along

consist

with ACE power

explained ground.

sensor

and rate The out-

stage _here

it is con-

The dc signal

then energizes

switch

in the control

and ya_ axes are held generators.

amplifiers_

Horizon

on for sensor

then modulated

dc

in

power

and signal

distribution

The normally-closed Power

contacts

may then be a_plied

for ECS sltitude

of relays

relay

system_

energized

control.

to 0AME power

forward

is the

to the RCS ring

The ring A and ring B

by transistor

relay

drivers.

Switching switching

represented

of horizon

amplifiers.

To turn off the OAME control

relays.

ring B valve drivers

Logic

pulse

by the switch

power and signal inputs to the OAME.

Mode

and rate signals

by the attitude

transistor

for the pitch

by the minimum

and amplified

to de-energized

RCS valve

signal.

and rate),

as ac signals.

and RCS attitude

A and/or

levels

to the demodulator

dc analog

or negative,

of 18 milliseconds

the same manner

s_plied

or negative

Attitude

and fed to the s_tch

is coupled

(attitude

(with the exception

to operational

are summed

stages

stages.

yaw and roll channels

are ac and are amplified

al_lifiers.

amplifier

and the demodulator/filter

to each of the pitch, signals)

of the signal

by blocks

provides

the

distribution in Figure

control

in the horizon 8-I1.

The logic

in the truth table at the right Figure

8-12

for attitude

shows how mode

mode

signal

scan mode.

These

function

of Figure

control

8-32 CONFIDENTIAL

switches

for each block

8-i1 as being

of signal

selections,

selections

are

is

ground or not is accomplished.

CONFIDENTIAL SEDR 300

PROJECT The transistor signals#

switches

provide

a grounded

by being in a conducting

and command position.

signals

it to cut off.

applied

to the ACE amplifiers. (horizon

application mands.

by selecting

This ungrounded

scan) logic

of +20 vdc,

switches

This provides

The pulse generator

or orbit modes.

Signal Processing

(Figure

_ne type

signal

selected

Attitude

the desired

are I_N transistors, a ground

circuit

for hand

to be and one with the

controller

com-

8-11) for each mode

establish

of control

ca n be determined

logid

table.

by referring

The P and I blocks, stages.

Signals

to the ACE are either

in-phase

or out-of-phase

exception

of the de horizon

sensor

input).

generates

an in-phase

signal

which,

A negative positive

switch

the bias !voltage to turn on switch A

the gain for rate[amplifier

Inputs

signal

and conduct

through

Attitude

mode

land mode 2 (pulse),

and the mode

selections,

reference

control

to the logic block in each channel mode

to attitude

to thei base of a PNP transistor,

1 (direct),

signal provides

when in the pulse

state.

state allows

The mode

condition

the appropriate

a +20 vde bias voltage

biasing

of the M4

or non-conducting

are obtained

This applies

or not grounded

error

attitude

displacement,

thrusting.

By referri1_

selection

of mode

5 provides

A positive

attitude

in turn, will

generating

command

an out-of-phase

to the logic

a computer

ae signals

table,

roll input

(with

displacement negative

signal,

through

A roll attitude

is fed into the three-stage

amplifier.

The ampl_fier

valve driver.

_e

output

signal

will

selected

the function

signal

or command

for an input

8-33 CONFIOENTIAL

command

signal

of

to ACE. attitude

will be used to tur m on the appropriate

li_Jiter is used to limit attitude

thrusting.

it may be seen that the

logic block DR and is the only attitude error

the

amplitude.

solenoid _e

out-

CONFIDENTIAL SEDR 300

._-_-_.

2.O_,_._EG j PITCH BIAS

_

I

102K

21.5K

'GYRO

I ,13VRMS,/DEG/SEC

20OK

°'+VRMS'_AxI

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FRATE

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*

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m J_

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L_

pL_

_

I [PI ME° GAIN

HiGH GAIN

(IpPp) (I'pPP)

_

_

LOW GAIN

(l'pP*p)

IPPI

(B-GN_ORD'F SWA S

A)

/

57 6K ._5,_K

49 9K

,CONTROLLERI.G,S,¢ .v qvv. •

4

1:1

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124K

_

T

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54.9K AMp

YAw IRA'EG_O 1.13VRMS/OEG/SEC

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49.9K --

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T 2_K []

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294K

I"_C_lll.,

T DEG/SEC1 " I/" 210K

k/

MEO GAIN (Pyl'y) LOW GAIN (l'yP'y) 57.6K

102K 49.9K

ICOMPUTER26vI.SVRMS/6_b_.K

130K 1.Suq/OEGJ

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ROLL AXIS

IpLATFGRMISV RMS MAX (REF)I _,.,,... .262V _. _

RATE GYRO

CONTROLLER

54.9K

I ,13V RMS/DEG/SEC

[]

4_2'7ua/'DEG

AMP

:v

100K

°EG/SECT I/

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IO, R.,,0EO,,EC '"K

RATE

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86.6K

T 105K

15.4K 86]:6:_K_ I_

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(IRPR) ,_7!!H7.87K GAIN (PRi'R) _ ME° GAIN _ LOW GAIN (I'RP_R)

CONTROLLER(2_I_ "j

I

/

_721

t I |

U Figure 8-11 ACME Functional 8-34 CONFIDENTIAL

Schematic

(Sheet 1 of 2)

VENT MAN

l

i

I

SWITCHES LONG MAN LAT MAN SWITCHES

I MOOECM° I

CONFIDENTIAL SEDR 300

_...._=_

PROJECT GEMINI LOGIC TABLE

tim

LOGIC FUNCTIONS WHERE (') DENOTES NOT GROUND IN PHASE CHOPPER

75K

42.2K

2.2J_v_

OUT OF PHASE __ I CHOPPER



__ 7SK

I

A = M1 ÷ M2 PULSE + M4 PULSE B = Mt + M2 ÷ M4 C'p = M 3 +M 5 +MsD +M 6 C'R =M3 +Ms +MsD +M6

2.2

• •

I_R =RING A +RING B +M S +MsD + M 6 "P = RING A + RING B + M5 + MsD + M6 I'y=RINGA+RINGB+Ms+MsD+M6 K'p =M 6

42.2K

150K

K'R = M6 K'y = M6 M' R =M 5 +MsD P'p = M5 = MsD P'R = M5 + MsD ply=MS +MsD

* SWITCH & INVERTER SWITCH & INVERTER

C'y=M3+Ms+M5D+M6D'R =Ms

AMP

I

DAMS SVDJ . / T°SOLENO,D VALVES

PITCH HAND CONTR

M 3 = RATE M2 PULSECMD M4 = HOR SCAN M 5 =RE-ENTRY MSD = RE-ENTRY RATE CMD

r sw,TcH -

I

IMIATT'TUO PEATORE

JI

J i

150K

I

M6

10:1

tELAY DRIVERS __

AMp

_CS

F .TO SOLENOID

I 2' I

'4V_10K

CHOPPER IN PHASE

J

--

75K

DAMS SVD

SWITCH I

I

_

I

YAW HAND CONTR

42.2K

I

VALVES

J

OUT OF PHASE CHOPPER

7SK

1S0K

+ SWITCH & INVERTER TO SOLENOID

VALVES

- SWITCH & INVERTER

AMP

DAMS

SVD

--

CONTROL

FUNCTIONS

i I



I

VALVES VERTMAN kSOLENOID

I

SOLENOID LONGMAN VA_.VES

J

SOLENOID VALVES EAT MAN

GAME

F'i

LOGIC I

IB

"

"

JJJJl

I

ROLL HAND CONTROLLER

I

SWITCH

SUPPRESSOR SPIKE DIODES

F

I

I MODE

7

_

I

-

I . i PITCH UP, YAW RT, ROLL RT, GIVE HAND CONTROLLER COMMANDS ERROR SIGNAL.

I_

m

'

J

ALL CAPACITANCE

VALUES ARE IN MICROFARADS.

Schema

8-35 CONFIDENTIAL

ROLL LEFT,

SENSOR OUTPUT.

PHASE REVERSAL IN RATE PRE-AMP & ATTITUDE mE-AMP. BY 3 .guo PEAK TO PEAK WAVE. + SWITCH ACTIVATED BYSQUARE 3ua Pdv_S IN-PHASE SINE WAVE OR + SWITCHES DRIVE POSITIVE TORQUING

Figure 8-11 ACME Functional

RATE & ATTITUDE

PITCH DOWN,

PITCH UP & ROLL RT GIVE POE HORIZON YAW LEFT IN-PHASE.

_

TO ALL AXES

IN-PHASE

PRI/SEC ELECTRONICS

SELECT BY AXIS.

(Sheet 2 of 2)

SOLENOID

VALVES.

CONFIDENTIAL SEDR300

....

\HOE

\

DIRECT

=

SCAN

m•

i B

RATE CMD (RE.ENT)

PULSE

SINGLE PULSE

PULS Ill

ATTITUDE

PULSE COMMAND _10V DC

I

GENERATOR _t

PLAT

CONTROL

(6 pLACES)

SOLENOID

._

mRECT AND

J +2OV DC

J

IVER

PULSE COMMAND

J

-10V

DC

(6 PLACES)

I ATTITUDE HAND CONTROLLER

(M4 PULSE) MI

(_O_

DIRECT

22V DC -10V DC ( "A"

M2 kr_C)_

RATE

PULSE

GYROS

-1OV OC_

; I M3 _

RATE CMD

I M4 (..T_C)_

HOR SCAN

"B"

_,

v

C'R= M3 + M5 +MSD÷M6

_>

,1" C_Y=+MSD+M6M3 +M5

TYPICAL PNP M5 0_

(RATE

RE-ENT

M' R : M5 ; M5D

SWITCH (1) PLACES)

_,,,_

O'R= M5

(ROLL)

COMPUTER (REF)

RATE CMD bM5Dcy _

M6

O'_

Z

RE-ENT

_I

PLAT

_

I,p=RINGA+RINGB+M5

SWITCH

I'R= RING A + RING B + M5 ÷ MSD +M6

TO GND

+ MSD _b'_6 I=y: RING A +RING +M5D+M6

I_1

_ B +MS

P'R : M5 +MSD

GAIN CON-

P'y = M5 ÷MSD P'F;: M5 +MSD ACE-MODE

LOGIC

I.

IN

2.

REFERTO FIGURE 8-11 (FUNCTIONAL ACE CIRCUITRY

LOGIC FUNCTIONS

(') DENOTES-NOT

GROUND.

SCHEMATIC)

FOR

Figure 8-12 ACE Mode Logic Switching-Attitude 8-36 CONFIDENTIAL

O

Control

CONIFIDHNTIAL

P put of the three-stage in-phase

and energizes

amplifier

ator will

either

the positive the ground

a prescribed

used in the pitch

Rate Signals

to either

stage.

dc signal,

drivers_

The output

which

low-hysteresis

the of

is filtered

switch.

The minimum

Energizing

pulse

gener-

to turn off in less than 18 milliseconds, i

thruster

force.

Minimum

pulse

generators

are

only.

8-11)

rate and rsie

command

signals

Cp, Cy and Cr through

gains through

rectified

valves

minimum

coupled

of the demodula$or

for the valve

and roll channels

(Figure

is transformer

or negative

not allow the solenoid

thus assuring

Angular

section

stage is a full-wave

the switch provides

F

switch

or the out-of-phase

the demodulator

blocks

,

are provided

the selection

the rate amplifiers

of modes

by the logic M3, M5, MSD,

are varied by the functions

Ip, Iy, Ir, Pp, Py, and Pr, with the selection

functions

of

and M6.

Signal

of logic blocks

of th_ re-entry

modes

or plstform

I

mode.

Rate

control

signal

solenoid

inputs

are used

valves.

Roll

in the ssme manner

rate signals

as attitude

are summed with

signals

to

the computer

command

i

signal

and the proportional

of the logic

block

crosscoupling signals signal

MR, with

of roll rates

are proportionally for cancellation

output

is fed to the swilch

of the re-entDy modes of control, provides i into the yaw axis for r_-entry control. Roll rate coupled

of part

into yaw.

This provides

of the yaw rate command i

HorizonSensorSignals

!

pitch

and roll

to out-of-phase the pitch

horizon

signals

choppers sensor

The function

selection

bility,

Sensor

amplifiers.

are positive

in ACE. output

or negative

A -5 degree for

pitch

signal

8-37

for proper

sta-

dc and are fed directly

pitch!bias

down orientation.

CONIFIOENTIAL.

an opposite-phase

voltage

is summed with

T_e output

of

the

CONFIDENTIAL

PROJECT __

GEMINI

$EDR3O0

chopper

will be of a phase opposite

the attitude

displacement

attitude

displacement

will

result

in an out-of-phase

attitude

displacement

will

result

in an In-phase

then amplified attitude

scan mode,

energizes

the

the

along

the minimum

with

in-phase

(hunting would result control

RCS Valve

vide e circuit energized

utilized

lag feedback

is

as an

provides

by other

networks

The lag network

operation,

ground

and

choppers

discharge

anti-hunting

of the horizon

relay

sensors

rate,

control

if no anti-

when

8-4) weighs

removable

diode

thruster

boards

as well as fixed co_aponents. the fixed

suppression

compone_t_,

power

They pro-

The relays

receiving

thruster

or the attitude

suppression

are

is provided

hsnd to

is interrupted.

(OA_) 8 pounds,

(2-reley

s;_ attitude

solenoid

valves.

8-38

CONFIDENTIAL

has a re_ovsble

boards

_ue replaceable

function

for the m_neuver

upon

switches

spike

spproxin_ately

module

conduct

logic

AND _._hrEUVERELECtrONICS

(Figure

with nor_rJally-open con-

and the RCS ring switch.

which

torque

Zener

are relays

is in the ACt_ position.

drivers

from the control

8-1B)

valve

when the switch

genersted

three

(Figure

the solenoid

the voltage

tion with spike

between

by transistor

ORBIT ATTI_JDE

board)

in the same manner

circuits

signal.

generator

drivers

switches.

contains

- capacitance

from the slow response

direct

This unit

to energizing

or out-of-phase pulse

valve

co_ands

controller limit

This signal

Drivers

connected

firing

logic

output).

and a negative

were used).

The RCS solenoid tacts

in addition

resistance

for either

hunt

by the on-off

output,

signal.

The horizon modes,

and processed

(a positive

end 1-component

module v_Ive

boards, drivers

cover

and

module

in conjuncand provide

CONFIDENTIAL

PROOECT

Functional

Control

Attitude

CO,hands

to the OAi_t are either

logic cor_msmc]sto the solenoid

driver

of ACiZ (_ee Figure transistors

the solenoid

to limit

Maneuver

Control

Maneuver

cock,ands

ground

8-14-).

package

8-i_).

originate

to limit the voltage

(Figure

_nis provides

8-4) contains

three

The rate gyro package

rate inputs°

gyro may be turned Two _/ro packages mately

8

The gyros

spike

when

logic

to energize

supp_.ession is

js interrupted.

hand

controllers

obt_.ined by applying

suppression

checkout.

rate gyros,

are orthogona!ly

Application

synchronization

ground

power

to the

firing

solenoid

valve for'

is provided

thruster

a circuit

power

by the OA_._ is interrupte6.

(RGP)

three axes.

put durin_

switch

spike generated

sealed.

of spin motor

grounds

of the two maneuver are

torque

dioSc: spike

when thruster

controller

hermetically

attitude

thruster

sigr,_ls, the vc_Ivc

circuit

Zener

con_nand signals

diode

eomm_nd

the

system.

from either

Conventional

RATE GYR0 PACKAGE

receiving

generated

hand

or negative

drivez's from the cont_o!

of the propulsion

the voltegc

positi_e

Upon

conduct.

the proper

firing.

The RGP

_alve

Translatio_.]

through

thruster

will

valves

provided

(Figure

,4

Oper_tion

Attitude

section

GEMINI

provides

Each

on or off without are provided

a check

gyro

mounte8

ac analog

of a gimbal

provide

each Indi_idually

for redundancy

pounds.

8-39 CONFIDENTIAL

outputs,

torquer

current

of gyro operation

is separately

affecting

for rate

excited

the operation and have

mounted

and

sensing

in all

proportional

to

and monitoring and pickoff

out-

so that any individual of the other

a total

weight

two.

of approxi-

CONFIDENTIAL SEDR300

f_'-

F-_---

]

=o

_:._

I<_

--.vU o,.-¢ _=,-

L.2

I Ii

-

I

I

>_

,_,>-

>_'.2

O

_(° u.

_'z=_l ,. _

''O'-L

I

,l I

I

__-_ _ I

=_-I

__o

_

'

I

I

°_

11

I

I"i

I I

k____

I _._-I,,I

I _I

tI

jI

--

__z _

_

_z

o__z _o

Figure

Zo_ o_

8-13

RCS

& OAMS

Attitude

8-40 CONFIDENTIAL

Valve

Drivers

_

=

_.

>_ __z

CONFIDENTIAL

____-_. "__

SEOR 30° PROJECT GEMINI

I

"-_Rcu,-rl

CONTROLLER

FWD-AFT

I

I I I

I

, P,CAL I TWO

Fwo_

I

h

AFT

I

__

soV_;_os _._O_E_J

_%._ I

_

J

_J

Figure

8-14

TO OAME SPIKE SUPPRESSOR

ACME

Maneuver

Control-Simplified 8-41

CONFIDENTIAL

L

Block

Diagram

CONFIDENTIAL

PRO,JECMINI SEDR 300

POWER

INVERTER

The power

inverter

use by the AC_ 7 pounds

PACKAGE (Figure

8-4) converts

subsystems

and horizon

sensors.

and consists

of the

following:

tor, power amplifier,

output

filter,

and oscillator

starter.

spacecraft

dc power

to ac power

The unit weighs

current

and voltage

regulator-controller,

The 26 vac, 400 cps power

approximately

regulators,

switching

inverter

for

output

oscilla-

regulator

is supplied

the following: a.

b.

ACE pc_er

d.

reference

demodulators

and dc biasing

Rate

20 watts

power c.

supply:

gyros:

for motor

Horizon

starting

ll watts

for bias

voltages

Attitude

hand controller:

for the choppers,

voltages.

and piekoff

sensors:

power

power and 16 watts

excitation. operational

and pickoff

power,

as reference

excitation.

0.5 _tts

for potentiometer

excitation. e.

Telemetry:

f.

FDI:

g.

Rendezvous

1.0 watts

for demodulation

reference.

8.2 watts Radsr:

for angular

8-42 CONFIOENTIAL

runming

reference.

to

CONFIDENTIAL

INERTIAL

GUIDANCE

!

SYSTEM

TABLE OF CONTENTS TITLE

_-

PAGE

SYSTEM DESCRIPTION.. .... INERTIAL MEASUREMENT UNIT: : . AUXILIARY COMPUTER POWER UNIT: : . ON-BOARD COMPUTER.. ......... SYSTEM OPERATION. . . ....... PRE-LAUNCH PHASE .... . . .... LAUNCH PHASE . . . ......... ORBIT PHASE. .......... RETROGRADE PHASE .......... RE-ENTRY PHASE . . . .... CONTROLS AND INDICATORS_ . ..... SYSTEM UNITS. , . . ...... • • INERTIAL MEASUREMENT UNIT ...... AUXILIARY COMPUTER POWER UNIT .... DIGITAL COMPUTER.. .......... SYSTEM DESCRIPTION .... ..... SYSTEM OPERATION . . . ...... MANUAL DATA INSERTION UNIT: ...... SYSTEM DESCRIPTION ....... . SYSTEM OPERATION ..... . • . . AUXILIARY TAPE MEMORY .......... SYSTEM DESCRIPTION ......... SYSTEM OPERATION ....... INCREMENTAL VELOCITY'INDiCATOR. , . , SYSTEM DESCRIPTION ......... SYSTEM OPERATION ..........

8-43 CONFIDENTIAL

8-45 . 8-45 . 8-45 8-46 . 8-46 8-47 8-47 8-48 8-50 8-51 8-51 • 8-56 8-56 8-73 8-75 8-75 8-79 8-176 . 8-176 . 8-179 8-185 8-185 8-188 . 8-193 8-19_ 8-195

CONFIDENTIAL

PROJECT

GEMINI

JDE DISPLAY INDICATOR

_

DISPLAY

INDICATOR

ONTROLLER

INSERTION UNIT

MANUALOATA _

"_

_.

I PLATFORM CONTROLS INCREMENTAL

VELOCITY

AND

INDICATORS

/

/

J

INDICATOR

FUGHT DIRECTOR CONTROLLER

AUXILIAR

INSTRUMENTPANELS

_

//

--

_\

\\

__\

\ \

/

/

,,

il_'

NOTE [_

S,/C 8THRU 12 ONLY

/

II

f-.(\ DIGITAL

\

COMPUTER

i NERTIAL PLATFORM

INERTIAL GUIDANCE

\

,

J

SYSTEM ELECTRONICS

AUXILIARY

Figure

8-15 Inertial

Guidance

8-44 CONFIDENTIAL

COMPUTER POWER UNIT

System

SYSTEM POWER SUPPLY

CONFIDENTIAL

__

SEDR300

ims

,N_L.__

io

The Inertial Guidance System (IGS) consists of an Inertial Measurement Unit, an Auxiliary Computer Power Unit, an On-Board Computer, With Auxiliary Tape Memory and associated controls and indicators. illustrated in Figure 8-15. pressurized c_bin area.

The location !of all IGS components is

Controls and indicators are located inside the

The Inertial Measurement Unit, Auxiliary Computer Power

Unit, and the On-Board Computer are located in the un_ressurized left equipment bay.

The computer Auxiliary Tape Memory is mounted on the electronic module

coldplate located in the adapter section (spacecraft 8 through 12).

_"

_RTIAL

MEASUREMENT UNIT

The Inertial Measurement Unit (IMU) consists of three separate packages: inertial platform, system electronics, and IGS power Supply.

the

All three packages

function together to provide inertial attitude and acceleration information. Attitude measurements are utilized for automatic control, computations, and visual display.

Acceleration

measurements

are utilized

retrograde computations and displays. selector.

for insertion, rendezvous,

and

I_/ operation _s controlled by a mode

Cage, alignment, orbit rate, and inertial modes are available.

Plat-

form attitude measurements are available to each pilot on his attitude display group.

The I_

is also capable of providing _00 cps power to ACME inverter loads.

An AC POWER switch allows the pilot to select the source of 400 cps ACME power.

AUXILIARY ,

COMPUTER POWER UNIT

The Auxiliary Computer Power Unit (ACPU) provides protection for the computer,

8-45 CONFIOENTIAL

CONFIDENTIAL

PROJE-C-T _.

GEMINI

$EDR 300

from the spacecraft bus voltage variations. ACPU supplies temporary computer power. computer is automatically turned off.

If bus voltage drops momentarily, the

If bus voltage remains depressed, the The ACPU is activated by the computer

power switch. ON-BOARD COMPU_

The On-Board Cc_uter

(OBC) provides the necessary parameter storage and computa-

tion facilities for guidance and control. rendezvous, and re-entry guidance. of computations to be performed.

A computer mode selector determines the type

A START switch allows the pilot to initiate

certain computations at his discretion. completion of a computation.

Computations are utilized for insertion

The COMP light indicates the start s_d

A MAT._light indicates the operational status of

the computer and a BESET switch provides the capability to reset the computer in ease of temporary malfunctions.

A Manual Data Insertion Unit (MDIU) allows the

pilot to communicate directly with the computer.

Specific parameters can be

inserted, read out, or cleared from the cc_pater memory. Indicator (M)

displays velocity changes.

depending on computer mode.

An Incremental Velocity

Changes can be measured or computed,

An Auxiliary Tape Memory (A_4) that works in con-

Junction with the spacecraft computer is utilized in spacecraft 8 through 12.

It

provides greater memory capacity and allows in-flight loading of program modes in the computer. SYS_t

v_TION

Operation of the IGS is dependent on mission phase.

Components of IGS are util-

ized from pre-launch through re-entry phases.

Landing phase is not controllable

and therefore no IGS functions are required.

The computer and platform each have

mode selectors and can perform independent functions. 8-46 CONFIDIENTIAL

However, when computations

CONFIDENTIAL

PROJECT

GEMI

S

are to be made concerning inertial attitude or acceleration, the two units must be used together.

PHE-LAUNCH PHASE

Pre-launch phase consists of the last 150 minutes before launch.

This phase is

utilized to warm-up, check-out, prog_am, and align IGS equipment.

After warm-up

the computer performs a series of self checks to insure proper operation.

Infor-

mation not previously progr-mmed but essential to the mission is now fed into the computer.

AGE equipment utilizes accelerometer outputs to align IMU pitch and

yaw gimbals with the local vertical.

The roll gimbal is aligned to the desired

launch azimuth by AGE equipment.

LAUNCH PHASE

Launch phase starts at lift-off and lasts throush insertion.

During the first and

second stage boost portion of launch, the guidance fUnctions are performed by the booster autopilot.

If the booster radio guidance system should fail, a Malfunction

Detection System (MDS) provides automatic switchover to back-up (IGS) guidance. Back-up ascent guidance can also be selected manually at the discretion of the c_and

pilot.

The computer has been progxw,_ed with launch parameters and the

l_J provides continuous inertial reference for back-Up ascent guidance.

To mini-

mize launch errors, the computer is updated by ground stations throu@hout the launch phase.

In the back-up ascent guidance operation, the computer provides

steering and booster cut-off commands to the secondary booster autopilot. i

The

computer also supplies attitude error signals to the!flight director needles. IMU provides inertial attitude reference to the attitude ball.

At Second Sta@e

The

Engine Cut-0ff (SSECO) guidance control is switched from booster to Gemini IC_. 8-47 CONFIDENTIAL

CONFIDENTIAL

PRO,JECT

GEMINI

The con_uter starts insertion computations at SSECO and, at spacecraft separation, displays the incremental velocity change required for desired orbit insertion. When the required velocity change appears the command pilot will accelerate the spacecraft with the O_ ation the I_

thrusters to insertion velocity.

During acceler-

supplies attitude and velocity changes to the computer.

The

computer continuously subtracts measured acceleration from required acceleration on the display.

When insertion has been achieved the incremental velocity

indication will be zero along all three axes.

ORBIT PHASE

Orbit phase consists of that time between insertion and the start of retrograde sequence.

If the IGS is not to be used for long periods of time it can be turned

off to conser_T power.

If the platform has been turned off, it should be warmed

up in the 0AGE mode approximately one hour before critical alignment.

The

computer should be turned on in the PRE LN mode and allowed 20 seconds for self checks before changing modes. separate operations. ment.

IGS operation during orbit is divided into three

The initial part of orbit is used for check out and align-

The major part of orbit is used for rendezvous exercises and the final

portion is used in preparation for retrograde and re-entry.

,Check-Out& Alignment

l_ediately

after orbit confirmation the spacecraft is maneuvered to small end

forward and the platform aligned with the horizon sensors.

Horizon sensor out-

puts are used to align pitch and roll gimbals in the platform.

8-48 CONFIDENTIAL

The yaw gimbal is

._

CONFIDENTIAL

PROJECT

GEMINI

i

aligned through gyrocompassir_ techniques using the roll gyro output. i will align the yaw gyro to the orbit plane.

Platform !aligmnent will be maintained

by the horizon sensors as long as SEF or _EF modes are used. used when maneuvers are to be performed.

This

ORB RA_

ORB RA_

mode is

is ian inertially free mode

except for the pitch gyro which is torqued at approximatel_ four degrees per minute (orbit rate).

The purpose of torquing the pitch gyro is to maintain a

horizontal attitude with respect to the earth. long periods of time drift errors can occur. drift, the mode is switched back to SEF or _F

Rendezvous

_

If 01_ RA_

mode is used for

To eliminate errors due to _yro for aligr_ent.

Exercises

IGS operation during rendezvous exercises consists oflperforming inertial measurements and maneuver computations.

Radar target!information is provided i to the computer for use in rendezvous computations, platform alignment is performed in SEF or BEF mode prior to initiating a maneuver.

The co_uter

START

button is pressed to initiate computation of velocity changes and computed velocity requirements are automatically displayed on the IVI. Flight

director needles

are referenced to the computer during rendezvous exercises and indicate the attitude in which translational thrust should be applied.

When the spacecraft

is in the correct attitude for a maneuver, all of the!incremental velocity indicationwill

be along the foTward-aft translational axls_

As thrust is applied, the

supplies the computer with attitude and acceleration information to continuously update the M

indications.

When the maneuver has been completed the plat-

form can be realigned to the horizon sensors.

8-49 CONFIDENTIAl-

CONFIDENTIAL

PROJ--E-CT'-GEMINI

Preparation

for

Retrograde

& Re-Entr_

Preparation

for

retrograde

and re-entry

retrograde (requires turned

sequence. less

than

on one hour

approximately

The AS

re-entry

_0 minutes). before

one half

is

If

module IV is the

retrograde.

hour

to

stabilization and aligmnent. )

I_

(The

in the loaded

has been _ros

last into

turned

hour the

off,

it

and accelerometers

warm up and another

half

hour is

before

computer must be require

required

for

The attitude hall will indicate when platform

gimbals are aligned to spacecraft axes. to Blunt End Forward (_F)

performed

At this time the spacecraft is maneuvered

and the platform aligned with the horizon sensors.

The platform remains in B_F mode to maintain alignment until retrograde sequence. The computer retrograde initial conditions are checked and if necessary updated by either ground traok_n8 stations or the pilot.

Preparation for retrograde

and re-entry is completed by placing the computer in RE-EFt mode.

RETROGRAD_ PHASE

Retrograde phase starts 256 seconds prior to retrofire and ends approximate_v twenty-five seconds after retrofire initiation. phase

a minus

indicator. form

sixteen

degree

bias

At time-to-go-to

is placed in ORB RA_

is

placed

retrosrade mode.

At the start of retrosA_ade

on the pitch

minus

30 seconds

needle

of the

attitude

(_-30

seconds)

the

plat-

While the retrorockets are firing (approximately

22 seconds) the acceleration and attitude are monitored by the l_J and supplied to the computer for use in re-entry computations. for re-entry at retrofire. inertial

position

and attitude,

C_putations

The computer starts computations

are based on the time of retrofire,

and retrograde

8-50 CONFIDENTIAL

acceleration.

-

CONFIDENTIAL

PROJECT GiSMINI

1_-_

t_._E

Re-entry phase starts immediate_v after the retrorockets stop firing and lasts i until drogue chute deployment. After retrograde a 180° roli maneuver is perZ

formed and pitch attitude is adjusted so that the horizon can be used as a visual attitude reference.

The spacecraft attitude is controlled by visual

observation of the horizon until the computer c_anEs at approximately 400,000 feet. the flight director needles. computer during re-entry. signals to the computer.

a re-entry attitude

The spacecraft is then controlled to null Flight director needles are referenced to the

The l_J supplies inertial iattitudeand acceleration Bank angle commands are computed and displayed on

the roll needle for down range and cross range error ieorrection. The bank angle commands L_at between 0 to 500 seconds depending on the amount of down i

range and cross range error.

Pitch and yaw needles display down range and

cross range errors respectively.

Upon completion of =the bank angle commands

(spacecraft on target) a roll rate of 15 degrees per second is commanded by the computer.

At approximately 80,000 feet the computer co_nds

suitable for drogue chute deployment.

an attitude

Immediately after drogue deployment

the IGS equipment is turned off.

CONTROLS AND INDICATORS

Attitude

Display

Group

The Attitude Display Group (ADG), (Figure 8-16), consists of a Flight Director

8- 51 CONFIDENTIAL

CONFIDENTIAL

PROJECT

GEMINI

FLIGHT DIRECTORINDICATOR

FLIGHT DIRECTORCONTROLLER

COMPUTER

S,/C POSITION 5,6 AND 8 DESIGNATIONS S/C 9 THRU 12 2. 3. 1.

ASC CTCH PRELNUP

2. 3. I.

i

ASC PRELN NAV

_

I

4. RNDZ

4. RNDZ

I

5. 6.

TD PRE RE-ENT

5. 6.

PREDNAV RE-ENT

J

7.

(NOT

7.

ORB DET _

USED)

ROLL ERROR _

J

I

I

I

ROLL

!._

® I ,,_,TUD_ CO,,_NO ®l

REP_,EN_E

_ODE

2' PLAT CMPT "l_ )

; M,X R RAT_ ,,_

3. RDR

3. ATT

I

I

j

I

_)

J PITCH

®

I

@

I

(_)

_j

('_

I

,, J

Q(_)

,L

I

{ DISPLAY

_'--2c_"P'Tc"'

YAW

CROSS DOWN RANGE RANGE ERROR ERROR

I

ROLL

_

Fi

E u

ure

> _

:_ "_'I = I

_

I R 8-16 Attitude

E _

I

0 >_

RATE GYRO

Display

8-52 CONFIDENTIAL

Group

'

I

I

I

SLAVED TO GIMBAL _ATTITUDE _'_ 1 POSITIONS SPHERE OF THE

PLATFORM

_

CONFIDENTIAL

__

SEDR300

Indicator fiers.

(FDI) a Flight

Three

are provided

types of displays by the FDI.

each axis continuously the inertial needle

platform

platform,

attitude

rate,

attitude

indicates and/or

displayed

platform

and type

of signal available.

types

of signals,

schematic

the computer

FDC reference

selector

mode

determines

selector

Manual

Data

The _mnual

Insertion

determines

A scale

selector

Unit

message.

the computer

the source of signal

is slaved Three

by the

is included

in the

and indicates

of display

as

on the needles.

is c_pable

to

is provided

on the needles.

is included

The

Figure

8-16

the source

of producing

different

in the schematic. information.

The

The FDC

displayed.

(MDIU) consists

Provision

Keys are pressed

word

in a most

and a

directly

with

cancel or read out informal location in the computer

The first

location

keyboard

to enter,

a specific

for insertion.

memory

of a ten digit

the pilot to communicate

is made

is used to address

and set up coded messages address

selector

The MDIU allows

computer.

The keyboard

the computer

in

Unit

seven digit register.

tion.

the type

Data Insertion

the on-board

mode

of freedom

attitude.

on the needles

of the FIE switching Since

off)

attitude! rate information

is used to select the source and type of display a simplified

ampli-

and ADG power

The sphere

of HI or LO scale indications

includes

associated

360 _egrees

information.

and rate gyros.

FDI to allow the selection FDC

attitude

Information

radar,

(FIE) and their

axis sphere with

and always

display

by the pilot.

computer,

A three

gimbals

Controller

(attitude,

displays

type indicators

selected

Director

two keys that are pressed

and the next flve

significant

8- 53 CONFIDENTIAL

bit first

set up a coded order.

Negative

CONFIDENTIAL SEDR 300

values

are

inserted

represents

a minus

monitor button

by making

addresses switches

the messages. register.

The _

The Incremental

orbit

required

provided

a display

message

seven

digit

a 9.

The 9 then

register

is

used

panel

does not clear

to READ CUT, CI_AR,

the computer,

in the computer

Co-m_d

System

to

Push

and

it clears only the by the ground

capabilities.

Indicator

Indicator

(M)

for, or resulting

rendezvous

insert

the

into or read out of the computer.

on the register

provides fr_

computer. maneuvers

along each of the spacecraft

to manually provides

entered

of

The

can also be inserted

the on-board

correction,

number

a number.

switch

Velocity

through

first

which have Digital

Velocity

increments

not

a_d messages

Information

Incremental

and

are included

trackin 6 stations

trolled

sign

the

a display

a specific

Displays

of computed

maneuver.

are utilized

and retrograde. translational

The 1%'I is confor orbit

Velocity

axis.

insertion,

.ncrements

Controls

plus or minus velocity

increments

into the IVI.

of tape position

and module

words

words

velocity

are

are included The IVI also

from the auxiliary

tape memory.

Computer

Controls

Computer

controls

are located

the -_in instrument C_uter

controls

light, a MALF selector to be

panel consist

- center of:

light, a RESET

is a seven position

performed.

they are utilized.

on the computer

a COMPUTR_ switch, rotary

Modes of operation The CO_

console

light

controls

and indicators

(lower assy). mode

selector,

and an 0N-OFF switch which correspond

indicates

CONFIDENTIAL

See Fisure a START

switch.

selects

the type

the computer

on

8-15.

swltch,

The CO_eU_ER

to the mission

when

panel

a COMP mode

of c_,_utations

phase

in which

is running

through

CONFIDENTIAL

PROJ

its program

and provides

a means

of checking

computer

The START

_equencing. f

switch

is utilized

for manual

initiation

of certain

computations.

NOTE The START Junction and

The HALF

switch with

must be operated

the COMPUTER

mode

in coal

sel@ctor

the COMP light.

light indicates

when

a malfunction

has occurred i

and the RESET

switch

i

resets

the computer

resetting power

to

the computer the computer

IMU Controls w,

a RESET

computer

consist

switch,

is o_Y

An ION-OFF ii

capable

switch

of

controls

power! unit.

Two cage modes,

light indicates

of; a PLATFORM! mode J

rotary

The ATT light

tude portion

of the l_J.

that the IWJ has returned

switch

two align

a malfunction

of the I_J.

indicates

an ACC

s_lector. The PLATIZ0RM i which,[ in conjunction with the

on and off as we_l as control

are selectable.

when

selector,

and an AC POWER

turns the platform

rate mode of operation ACC

malfunctions.

and the auxiliary

is a seven position

AC POI_ER selector_

of operation.

for mcaentary

and indicators

an ATT light,

mode selector

The RESET Switch J

indicator.

& Indicators J

The IMU controls light,

malfunction

modes,

one _e

mode,

the mode

and an orbit

The align models are SEF and _F. has occurred

when

i_ the accelerometer

!

_ha__.a occurred

a malfunction

The RESET

switch

to nor_-I

operation.

The portion

in the atti-

will turn Qff the lights 3 indicating The ___8T

switch works

for momen-

I ;

tary _-_Ifunctions of either

type.

to

Inability

reset ithe lights i

indicates

a

!

pe _r_anent malfunction. inverter

on without

The AC POWER

operating

the

selector

platform

or

8-55 CONFIDENTIAL

allows electro_cs

_he pilot circuits.

to turn the IGS

CONFIDENTIAL

PROJECT

GEMINI

SEDR 300

SYSTEM UNITS

INERTIAL

MEASUREMENT UNIT

The Inertial Measurement

Unlt

reference

Spacecraft.

for the Gemini

the inertial packages

conform

total weight functions

and

attitude other

platform,

platform

to spacecraft

of 130 pounds. signal

routing

and acceleration

units of guidance

_ounted

(I_J) is the inertial

The IMU consists

electronics, contours

throughout

reference,

block

all

of three

separate

convenience

diagram

three

The platform

packages

All three

and have a

(Figure 8-17)

packages.

the IMU provides

and control.

and acceleration

and IGS power supply.

for mounting

A functional

on cold plates to prevent

attitude

indicates

In addition

to

ac and dc power for use in

and electronics

packages

are

overheating.

NOTE References

to x, y, and z attitude

translational guidance with

Inertial

pertain

only and should

structural

to inertial

not be confused

coordinate

axes.

Platform

The inertial miniature

platform

integrating

the gyro mounting housing

axes

and

(Figure

is a four gimbal

gyros and three

frame

moves freely

8-18)

(pitch block)

about them.

assembly

pendulous

accelerometers.

to remain

in a fixed

Major

components

8-% CONFIDENTIAL

containing

three

Gimbals

allow

attitude

of the platform

while are:

the

a housing,

CONFIDENTIAL SEDR300

c@ gimbal

structure,

accelerometers.

PROJECT

torque

motors,

The gimbals

gimbal

All gimbals,

dora. The inner roll

gimbal

occur

are used

pitch,

and 90 degrees

roll

inner

when

exists.

resolvers,

are: pitch,

roll, have

to plus

the possibility

structure

,

synchros,

to outside

except

is limited

to eliminate

on a three gimbal

angle

from inside

yaw and outer roll.

gimbals

GEMINI

_...y.;._ .___

and minus of gimbal

an attitude

gyros

inner

360 degrees

At this time the roll

Two roll

Gimbal

of 0 degrees

roll, of free-

15 degrees. lock.

and

yaw,

lock can 0 degrees

and yaw gimbals

in the same plane and the yaw gimbal

lock).

In the Gemini

between

the inner

cannot move about its axis (gimbal i an angle of 90 degrees is maintained

are

four gimbal platform

roll and yaw gimbals

thus preventing

gimbal

lock.

The inertial

compo-

i

nents are mounted F_

and shielding the pitch

from thermal

of the pitch

input axes block.

effects.

cube located

casting

The gyros

are aligned

Two sealed

for alignment

alignment

gimbal

block in a fixed relationship

accelerometer

housing

in the innermost

(Pitch block)

and associated

with the reference

with the three

optical

and testing.

quality

Both windows

on the stable

servo

loops

coordinate

mutually

windows

for rigidity

system.

perpendicular

are provided

provide

maintain

optical

axes

in the

access

to an

element.

System Electronics The system

electronics

package

of the I_.

Circuits

motor power,

accelerometer

contains

are provided logic,

the circuitry

for gyro

torque

accelerometer

necessary

control,

rebalance,

for operation

tJmlug

lOgic,

and malfunction

i

detection.

Relays

provide

remote

mode

control

8-57 CONFIDENTIAL

of the above

circuits.

spin

The

ELECTRONICS

ACC/_u_.LFLAMP ATIM_'LFLAMP _

I

RICAL I

I

El

TO COMPUTER_

0.2604CPS

GYRO MALFUNCTION LOGbC

TO COMPUTER_

ACCELEROMETER MALFUNCTION LOGIC

6*25 KC

TO COMPUTER

TO COMPUTER

TOCOMPUTER TO COMPUTER_

s

Figure 8-17 IMU Functional

Block Diagram

->

8-58 CONFIDENTIAL

(Sheet 1 of 2)

_

CONFIDENTIAL SI::DR 300

.f-==--.

I

ProJECT INERTIAL

PLATFORM--

"1

I "z" OMET

I POSITION SIGNAL

ii TocoMPu REFERENCE SIGNAL TO COMPUTER

!

i

i

=

u

=

_

_g "

I

=

pOSITION SIGNAL TO COMPU|ER

I

POSITION SIGNAL I'O COMPUTER

J•

15V 400_ FROM COMPUTER

m , • }

i



REFERENCE SIGNAL TO COMPUTER

I

,,

REFERENCE SIGNAL TO COMPUTER



O b



PLATFORM SIGNAL TO ADO (AT1'ITUDE POSITION DISPLAYGROUP)

HORIZON SENSOR(PITCH)'

SELECTOR(_EF) HORIZON SENSOR (ROLL)

PLATFORM POSITION "SIGNALS TO ACME

b ;



suPPLY

-CPS

CPSJ

'

r

ID I

>D1

I

Figure

8-17

IMU

Functional

Block 8-59

CONFIDENTIAL

Diagram

(Sheet

I

2 of 2)

+28v DC

CONFIDENTIAL f:_'_\

SEDR 300

L__V

PROJECT

GEMINI

NOTE PLATFORM CO'ORDINATES BODY CO-ORDINATES-Xb,

-Xp, Yp, Zp. Yb, Zb.

_

INERTIAL PLATFORM

_

....

I - VERTICAL ACCELEROMETER (Z AXIS) FIRST GIMBAL

(PITCH)-

ALONG COURSE ACCELEROMETER_ (X AXIS)

ACROSS CO (Y AXLS)

GIMBAL

Figure

8-18 Inertial

Platform 8-60

CONFIDENTIAL

Gimbal

Structure

(INNER ROLL)

CONFIDENTIAL

PROJECT

I GS Power

GEMINI

Supply

The IGS power supply (Figure 8-19) contains glmbal control electronics and the static power supply unit. platform.

Oimbal control electronics idrive torque motors in the

Separate control circuits are provided for leach gimbal.

The static

power supply provides the electrical power for the IMU, OBCI ACPU, MDiU_ M, ACME_ and horizon sensors.

Figure 8-19 indicates the types of power available

and the units to which they are supplied.

Attitude

Measurement

Attitude measurements are made from inertial platform igimbals and reflect the difference between spacecraft and gimbal attitudes, '

platform gimbals are main-

rained in essential_v a fixed inertial attitude by gimbal control electronics. As the spacecraft moves about the attitude axes, friction transfers some of the movement to platform gimbals.

Three miniature gyros are used to sense minute

gimbal attitude changes.

When gyros sense a change in attitude, they produce ; a signal proportional to the attitude error. Gyro outputs are then used by gimbal control circuits to drive g_mbals to their original inertial attitude. Gimbal positions relative to the spacecraft are measured by synchros and resolvers.

Synchro outputs are provided for attitude _isplay, automatic attitude i

control, and gyro alignment. transformation, are used. to the computer.

Two types of resolvers, p_-se shift and coordinate

Phase shift resolvers provide gimbal angle information

Coordinate transformation resolvers provide attitude signal

resolution for gimbal control purposes.

8.61 CONFIOENTIAL

CONFIDENTIAL

":.

PROJECT

GEMINI

INERTIAL PLATFORM ]0.SV 7.2KC

r_

I

+40V DC -40V DC -3V DC +35V DC

i,

+I2V DC +35V DC PRECISION

SYSTEM

ELECTRONICS

-40V DC PRECISION -35V OC

=

-22V DC +22V DC

! MAIN

BUS

+28v

_

÷28V DC •

AC POWER (SELECTOR) --

26V AC

400 CPS

L

IGS POWER 26vAc

SUPPLY

_ 400 CPS

•_VDC .i iv, i i MO,U I 2>

+ 28.6V DC ÷ 10.2V DC - 28.6V

DC

+ 20.7V

DC

_

+28V DC

26VAC

Figure

8-19

IGS

Power

8-62 CONFIDENTIAL

400CPS

Supply

(3

• I

26V AC 400 CPS

+28vDC +28vDc

>

I

COMPUTER

=

POWER UNIT AUXILIARY COMPUTER

J _

I"OACME, HORIZON SENSORS AND ATTITUDE DISPLAY

I

CONFIDENTIAL SEDR 300

Modes

of Operation

Seven modes

of operation

are selectable

by the astronaut.

The modes,

in order

and

The

of

;

switch position position

are:

is used

OFF,

SEF, ORB RATE,

for IMU warm-up

craft body axes.

Platform

horizon

In the

sensors.

a null is obtained

and to align

gimbals CAGE mode,

are aligned

small end forward.

synchro

outputs

horizon

sensor

with

A gyro

compass

Horizon

and the difference outputs

are balanced

loop aligns

gimbals When

is used to align the platform

flyiDg

_F,

the gimbals

spacethe

outputs

until

torquing

SEF (Small End Forward)

sensors

gimbals.

when

When

are aligned

with

CAGE

with

null,

and roll outputs

used to torque

the yaw gimbal

reach

axes_

with the horizon sensor pitch

with

by synchro

outputs

spacecraft

gimbals

to fine alignment

are torqued

synchro

FREE.

C_GE,

the platform

are caged prior

on the synchro.

stops and the gimbals mode

CAGE,

the orbit

the spacecraft are compared synehro

to earth

with

and

local

vertical.

plane.

-NOTE If horizon

sensors

SEF or _F

alignment

automatically

lose

track

modes,

switched

during

either

the platform

is

to ORB RATE mode. i

ORB RATE

(orbit

rate) mode

craft maneuvers.

ORB RATE

The pitch

gyro is torqued

a horizontal

attitude

for long periods BEF

is used to maintain mode

is inertially

at approximately

with respect

of time,

(Blunt End Forward)

drift

mode

attitude

free except

four degrees

to the earth.

can cause

reference

per minute

errors

is the same as SEF except

8-63 CON FIDENTIAL

for the pitch

If ORB RATE mode

excessive

during

spacegyro.

to maintain is used

in the platform.

that relays

is

reverse

the

CONFIDENTIAL

PROd

ECT'T--GMI

phase of horizon sensor inputs.

NI

The second CAGE mode allows the platform to

be caged in blunt end forward without switching back through other modes. mode is used during launch and re-entry phases.

FREE mode is completely

inertial and the on_v torquing employed is for drift compensation.

NOTE FREE mode is selected automatical_y by the Sequential System at retrofire.

Oimbal Control Circuits

Four separate servo loops provide gimbal attitude control. trates the signal flow through all four loops.

Figure 8-17 illus-

Gyro signal generator outputs

are used either directly or through resolvers as the reference for gimbal control. Both pbsse and amplitude of signal generator outputs are functions of gimbal attitude. output.

Gimbal number one (pitch) is controlled directly by the pitch gyro

Error signals produced by the pitch gyro are amplified, demodulated,

and compensated, then used to drive the pitch gimbal torque motor.

The first

amplifier raises the signal to the level suitable for demodulation. fication, the signal is demodulated to remove the 7.2 KC carrier.

After ampli-

A compensation

section keeps the signal within the rate characteristics necessary for loop stability.

When the signal is proper_v conditioned by the compensation section,

it goes to a power amplifier.

The power amplifier supplies the current required

to drive the gimbal torque motor.

The torque motor then drives the gimbal ma_n-

raining gyro Outputs at or very near null.

8-6_ CONFIDENTIAL

CONFIDENTIAL SEDR 300

Roll and yaw servo loops utilize resolvers to correlate gimbal angles with gyro outputs.

Inner roll and yaw gimbals are controlled by a coordinate

transformation resolver mounted on the pitch gimbal.

When the spacecraft

is at any pitch attitude other than 0 or 180 degrees, some roll motion is sensed by the yaw gyro and some yaw motion is sensed by the roll gyro.

The

amount of roll motion sensed by the yaw gyro is proportional to the pitch gimbal angle.

The resolver mounted on the pitch gimbal angle.

Resolver

output is then conditioned in the same manner as in the pitch servo loop to d_ive inner roll and yaw gimbals.

The outer roll gimbal is

servo driven from the inner roll gimbal resolver.

A

coordinate transformation resolver mounted on the inner roll gimbal, monitors the A_le

between inner roll and yaw gimbals.

If the angle is anything other

than 90 degrees an error signal is produced by the _esolver.

The error signal is

conditioned in the same manner as in the pitch servo loop to drive the outer roll gimbal.

One additional circuit (phase sensitive electronics) is incluced in the

outer roll servo loop.

The outer roll gimbal torque motor is mounted on the

platform housing and moves about the stable element with the spacecraft. i

As

the spacecraft moves through 90 degrees in yaw, the direction that the outer roll i gimbal torque motor must rotate to c_ensate

for spacecraft roll, reverses.

Phase sensitive electronics and a resolver provide the phase reversal necessary for control.

The resolver is used to measure rotation of the yaw gimbal about !

the yaw axis.

As the gimbal rotates through 90 degrees in yaw, the resolver

8-65 CONFIDENTIAL

CONFIDENTIAL

PROJECT __

output

changes

phase

sensitive

motor

drive signal

Pre-Launch

phase.

Resolver

electronics.

for that

launch azimuth.

Platform

an error

gimbal error

mounted

up attitude control

is aligned

is compe/ed

phase by the

phase, the torque

synchro

the platform

to local

vertical

is not properly

aligned output

the gimbal.

is used by AGE

The outer

output

to the launch

8-66 CONFIDENTIAL

then produces

a

by a

is in a 90 degree

is transferred

the roll gimbals

and the AGE reference

is aligned

and applied

is coordinated

all of the yaw gyro output

roll

the launch azimuth

by AGE equipment

the spacecraft

drive

If

When the gyro is torqued

Gyro output

The electronics

X and Y

and must be

The yaw gyro signal generator

Since

for local

due to gravity.

with a signal representing is conditioned

and the

to the local vertical,

for the gyros.

on the pitch gimbal.

electronics.

and must therefore

are the reference

is used to align

generator.

essentially

guidance

The accelerometer

to the input torque.

exists between

signal exists,

signals

The error signal

signal proportional

ascent

is aligned

the platform

signal which

to the yaw gyro torque

pitch

changes

sense any acceleration

signal exists. torque

output

by AGE equipment.

resolver

to a reference

output

X and Y aecelerometers

is sensed,

to generate

synchro

The platform

When the platform

until no error

it produces

for hack-up

are level and cannot

any acceleration

equipment

When the resolver

reference

purpose.

alignment.

accelerometers

torqued

is compared

Alignment

be aligned

vertical

output

is reversed.

The IMU is the inertial

gimbal

GEMINI

SEDR300

signal.

azimuth.

to roll

until

no

When no error

CONFIDENTIAL SEDR300

PROJECT

GEMINI

Orbit Alignment

Alignment of the platform in orbit is accomplished by referencing it to horizon sensors.

the

Placing the platform mode selector _n SEF or BEF position

will reference it to the horizon sensors.

Pitch and roll horizon sensor outputs

are co_pared with platform pitch -nd outer roll synchro outputs.

Differential

amplifiers produce torque control signals proportional to the difference between sensor and synchro outputs.

Torque control signals are used to drive pitch and

roll gyro torque generators.

Gyro signal generator outputs are then used by

gimbal control electronics to drive platform gimbals, i When synchro and horizon sensor outputs balance, the pitch and roll gimbals are aligned to the local verti. cal.

The yaw gimbal is aligned to the orbit plane through a gyro compass loop.

If yaw errors exist, the roll gyro will sense a component of orbit rate.

The

roll gyro output is used through a gyro compass loop %o torque the yaw gyro. Yaw gyro output is then used by gimbal control electronics to drive the yaw gimbal.

When the roll gyro no longer senses a component of orbit rate, the yaw

gimbal is aligned

to the orbit plane.

All three gimbals are now aligned

remain aligned as long as SEF or BEF modes are used.

and will

The pitch Erro will be

continuously torqued (at the orbit rate) to maintain a horizontal attitude.

If

horizon

sensors

lose

track

while

platform

is

in SEF or _F

modes,:

platform

is

automaticall_

switched

ORB RATE mode.

8-67

CONFIDENTIAL

the

the to

CONFIDENTIAL

PROJECT

Orbit

Rate

Circuit

The orbit rate circuit

is used to maintain

during

orbit maneuvers.

Local

during

m_neuvers

they

attitude

with

four

degrees

Torque

is

because no external

per

minute.

obtained

amplifier. rate.

GEMINI

The Orbit

rate

will

bias

track.

The torque

represents

a DC bias the

is

lose the

drives

pitch

adjustable

to the local vertical

cannot be provided

reference,

by placing bias

vertical

aligmnent

To maintain

pitch

gyro

and

is

the

on the gyro

by horizon

torquer can

be

torqued

of

at set

a horizontal at

spacecraft

output

approximately

orbit

the

pitch

match

rate. differential

approximatel_v

to

sensors

orbits

the

orbit

of

various

altitudes.

Phase

Angle Shift Technique

Phase

A_le

ability.

Shift Technique

(PAST) is a method

One of the factors

unbalance.

The effect

point

which affects

of unbalance

on with the synchronous different

_

motor's

each time

errors

by a factor

of spin motor excitation

will vary with field.

it is started.

Drift

of ten.

per hour. To cancel

30 degrees

now tend to cancel and become

it can be

compensated

compensation

circuits.

gyro torque

generator.

for. )

errors

a meana

All three

gyro torque

compensation

848

control

the _ro

unbalance

shifts the phase the phase

is shifted.

is predictable

loops

apply

of lock

of reducing

Shlftin@

(When drift

circuits

torques

CONFIDENTiAl-

PAST

each time the phase

predictable.

rotor

can lock on to a

due to rotor

errors,

repeat-

in the point

The spin motor

drift

The drift compensation Drift

changes

PAST provides

point

gyro drift

is spin motor

at reg,,IA_ intervals.

causes the rotor to lock on a different Drifts

gyro drift

rotatiDg

are in the order of 0.5 degrees drift

of improving

contain

drift

a dc bias to each

in the opposite

-_

CONFIDENTIAL

_

direction

Attitude

SEDR300

as predictable

Malfunction

An attitude generator

drift,

excitation, Gyro

a stable

attitude.

Detection

malfunction

voltages.

maintaining

detection gimbal

signal

circuit

control

generator

performs

signals,

excitation

self checks

logic

timing

is checked

of gyro

signals,

for presence

signal

and critical and

proper

i amplitude.

Gimbal

are present. cal voltages

operation

signals

The logic timing (+22vdc,

tion is detected, If momentary

control

signal

-3vdc, +12vdc)

an ATT

light

malfunctions

by pressing

are checked (28.8kc)

the RESET

is che,_ed

are checked

on the

occur,

for th, length

control

the ATT

for

panel

indicator

signals

for presence.

i,resence.

Criti-

If a malfunc-

is automatically cam be restored

illuminated. to normal

button.

i N-OTE If the attitude malfunction, tions are

of time

I

measurement

circuits

the acceleration

not

reliable.

indica-

Acceler_eter !

axes will indications

not be properly are along

aligne_

-n_nown

and

axes. J

Acceleration

Measurement

Acceleration

is measured

platform.

Sensing

along

devices

three

are three

mutuall_ miniature

8-69 CON FIDEN'I"IAL

perpendicular i pendulous

axes of the inertial

accelerometers.

The

CONFIDENTIAL

PROJECT

GEMINI

accelerometers are mounted in the platform pitch block and measure acceleration along gyro x, y, and z axes.

Accelerometer signal generators produce signals

whose phase is a function of the direction of acceleration. output is used to control torque rebalance

pulses.

Signal generator

The torque rebalance

drive acceleromgter pendulums toward their null position. dc current whose polarity is controlled of rebalance

Rebalance pulses are

by signal generator output.

pulses indicates the direction

of acceleration

sum of the pulses indicates the amount of acceleration.

pulses

The polarity

and the algebraic

Rebalance

pulses are

supplied to the spacecraft digital computer where they are used for computations and incremental velocity displays.

Torque Rebalance Loop

Three electrically

identical

ometer pendulum positions.

torque rebalance

loops are used to control acceler-

Normally an analog loop mould be used for this pur-

pose; however, if an analog loop were used, the output would have to be converted to digital form for use in the computer.

To eliminate the need for an analog to

digital converter, a pulse rebalance loop is used. dc current pulses drive the accelerometer passes through null.

Short duration 184 milliampere

pendulum in one direction until it

Pulses are applied at the rate of 3.6kc.

passes through null, signal generator output changes phase.

When the pendulum

The signal generator

output is demodulated to determine the direction of the pendulum from null. Demodulator output is used by logic circuits to control the polarity of rebalance pulses.

If acceleration is being sensed, there will be more pulses of one polar-

ity than the other.

If no acceleration is being sensed, the number of pulses of

8-70

CONFIDRNTIAL

CONI=IOENTIAL

PROJECT __

GEMIIII

SEDR300

each polarity pulses,

will

be equal.

logic circuits

set up precision

inputs from the t_mlng timing

is essential

the current therefore pulses.

Each

pulse is also pulses

torque

provided

are the basis

is dependent

for rebalance torque i

pulse

is applied

Algebraic

supply

provides

measurements

are based

a negative

feedback

circuit

passed

through

a precision

resistor

and the voltage

to a precision

in the feedback

A pendulous

of

sum of the applied torquer,

a

of the rebalance

pulses be as near

current i on the number

current,

voltage

circuit

both

reference.

to correct

the current

in a temperature

Accelerometer

on the length

and amplitude,

the required

stable

are housed

Precise

Supply

current

stability

depends

su,_tion

that all

enhance

frequency

pulse timing.

to the accelerometer

it is essential

used

Precision

the same _uration

only on the algebraic f

of rebalance

by the computer.

Since acceleration

compared

the polarity

of the pulses. I

of pendulum

to the computer.

Current

A pulse rebalance

timing

the amount

time a rebalance

Pulse Rebalance

to controlling !

All pulses are precisely

is performed

ance.

circuits

because

pulse.

total

In addition

identical

of torque

as possible.

is employed.

The

rebalpulses

To maintain

supply output

drop across

a

is

the resistor

Errors

detected by the comparison are i any deviations in current. To further

supply and the pre_ision

controlled

for torque

voltage

reference

oven.

Dither

accelerometer,

unlike a gyrp, has an inherent

m_ss unbalance.

The

;

mass unbalance perfect

is necessary

flotation

to obtain

of the pendulous

the pendulum

gimbal

aCtion.

cannot be achieved

8-71 CON I=IDENTIAL

Due to the unbalance, and consequently

CONFIDENTIAL

PROJECT

GEMINI

SEDR 300

pressure

is present

caused by bearing The oscillation

on the gimbal bearing.

friction, (dither)

a low amplitude

prevents

enough to cause stlctlon. a i00 cps dither imposed

signal

on the signal

the gimbal.

generator

gimbal

field

signal beats against

down.

The dither motion

oscillation

is imposed

from resting oscillation,

current.

excitation

the dc field,

is not around

causing

is super-

field

(modulator)

long

are required:

current

a magnetic

the glmbal

the output

on the g_mbal.

two signals

to a separate

effect,

on its bearing

The dc field

and creates

The I00 cps dither is applied

dither

the stlction

the gimbal

To obtain

and adc

To minimize

around

coil.

to oscillate

axis and consequently

The up end

no motion

is sensed by the signal generator.

Accelerometer

Malfunction

Detection

An acceleration

malfunction

velocity

and critical

pulses

the three axes are checked seconds,

it indicates

critical

voltage

detection

normal

occur,

operation

velocity

If pulses

for presence.

is automatically

the accelerometer

by pressing

self checks of incremental pulses

are absent

flop did not reset between

is checked panel

performs

Incremental

for presence.

an ACC light on the control malfunctions

voltage.

that a flip

(+12 vdc)

circuit

malfunction

the RESET

circuit

does not

affect

8-T2 CONFIOENTIAL

circuits

measurements.

The

is detected,

If momentary

can be restored

button.

attitude

than 0°35

set pulses.

illuminated.

of the accelerometer

longer

If a malfunction

NOTE Malfunction

from each of

to

CONFIDENTIAL

PROJ

AUXILIARY COMPU_R

i

POWER UNIT

The Auxiliary Computer Power Unit (ACPU) is used in conjunction with the IGS power supply to m-_ntain the correct dc voltades at the computer.

The computer

cannot function properly On low voltage either as a transient or a depression. Abnormal voltages can cause permanent cha_es

in the computer memory.

Three

types of circuits are provided in the ACPU to prevent a low voltage condition at the computer.

The first circuit is a transient sense and auxiliary power

control circuit.

The second circuit is a low voltage Sense and power control

circuit and the third is auxiliary power.

The .ACPUis turned on and off with

the COMPUTER ON-OFF switch.

Tr-naient Sense Circuit

The transient sense circuit is designed to sense and correct tr__n.ientlow voltage conditions.

A series type tz__-aistorvoltage regulator holds e_x_liary

power off the llne as low is normal.

as IGS power suppl_ computer voltage regulator voltage drops below a min__mu_ of 17.5 volts,

If regulator voltage _entarily

the transient sense circuit detects the drop and turns on the series regulator. The redulator the

desired

Low Voltage

then

places

auxiliary

power

on the

line,and

maintains

voltage

at

level.

Sens.e Circuit

A low voltage sense circuit prevents the computer from operatin_ on low voltage. When the computer is turned on, the low volta6e senseicircuit insures that spacecraft bus voltage is above 21 volts before allowing power to be applied to the

8-TS CONFIDENTIAL

CONFIDENTIAL

computer.

If the computer is already on when a low voltage condition occurs,

the transient sense circuit will maintain normal voltage for i00 milliseconds. If spacecraft bus voltage is not back to normal after ZOO milliseconds the low voltage sense circuit initiates a controlled shutdown of the computer.

Computer

power is controlled through contacts of a relay in the low voltage sense circuit. When the low voltage sense circuit detects a voltage depression it deenergizes the relay.

Contacts of the relay initiate a computer shutdown in a manner

identical with the computer power switch.

When the low voltage sense circuit

turns off the computer it also breaks power to all ACPU circuits except low voltage sense.

If power were not broken to the transient sense circuit it would

attempt to maintain normal voltage at the c_puter.

In attempting to maintain

normal voltage the auxiliary power capability would be exceeded.

Auxiliar_

Power

Auxiliary power consists of a battery and a trickle charger.

A O.5 ampere-hour

nickel cadmium battery is used to supply computer power during spacecraft bus low voltage transients.

The battery will supply up to 9.8 amperes for periods

of i00 milliseconds or less.

A trickle charger is provided to maintain a full

charge on the battery.

The charger consists of a transistor oscillator, trans-

former, and rectifier.

The oscillator changes static power supply dc voltage

to ac.

The ae voltage is then stepped up with a transformer and changed back to

dc by a full wave diode rectifier.

Rectifier output is then applied, through

a current limiting resistor, to the battery. to 25 milliamperes.

The resistor limits charging current

Provision is included to charge the battery from an external

source if desired.

--

8-74 CONFIDENTIAL,

CONFIDENTIAL

PROWl _._

SEDR 300

I

,DIGITALC_ER SYSTEM DESCRIPTION

General The Digital Computer, hereinafter referred to as the computer, is a binary, fixedpoint, stored-program, general-purpose computer, used to perform on-board computations. deep.

The computer is 18.90 inches high, 14.50 inches wide, and 12.75 inches It weighs 58.98 pounds.

Figure 8-20.

External views of the computer are shown in

The major external characteristics are s_arized ;

in the accompany-

ing legend.

Using inputs from other spacecraft systems, along with a stored program, the _.

computer performs the computations required during the pre-launch_ insertion, catch-up, rendezvous, and re-entry phases of the mission.

In addition, the com-

i

purer provides back-up guidance for the launch vehicle during ascent.

lu_uts and Outputs The computer is interfaced with the Inertial Platform_ System Electronics, Inertial Guidance System Power Supply, Auxiliary CompUter Power Unit, Manual Data Insertion Unit, Time Reference System, Digital Co_and

System,

Attitude Display, Attitude Control and Maneuver Eleet_onics, Titan Autopilot, ! I

Auxiliary Tape Memory (spacecraft 8 through 12), Pilots' Control and Display Panel, Incremental Velocity Indicator, Instrumentationi System, and Aerospace Ground Equipment.

In connection with these interfaceS, the computer inputs and

outputs include the following:

Inputs _0 discrete 3 incremental velocity

8-75 CONFIDENTIAL

CONFIDENTIAL

.. _-__

SEDR300

__._ LEGEND I1_M !

Q

NOMENCLATURE

MOUNTING

ACCESS COVER

CONNECTOR

J4

CONNECTOR

J5

(_

CONNECTOR

J7

Q

CONNECTOR

J3

(_

CONNECTOR

J2

Q

CONNECTOR

JI

I (_)

CONNECTOR

J6

MOUNTING

ACCESSCOVER

i _

MOUNTING

ACCESS COVER

i (_

MOUNTING

ACCESS COVER

_

ELAPSED TIME INDICATOR CONNECTOR

ACCESS COVER

(_

RELIEFVALVE

(_

MOUNTING

' (_

_)

ACCESS COVER

HANDLE

MOUNTING

ACCESS COVER

IOEN TIFICA TION (_

Figure

8-20

Digital

Computer

8-76 CONFIDENTIAL

PLATE

_

MAIN

ACCESS COVER

(_

BUS BAR ACCESS COVER

(_)

_us8at ACCESS cover

(_)

RELieFVALVE

---"

CONFIDENTIAL

SEDR 300

Inputs

:

(cont)

3 gimbal

angle

2 high-speed

data

(500 kc)

i low-speed data

(3.57 kc)

i low-speed

(182 cps)

data

i input and read-back

(99 words)

6 dc power

(5 regulated,

i ac power

(regulated)

i unregulated)

Outputs 30 discrete 3 steering

command

3 incremental I decimal

velocity

display

(7 digits)

I telemetry

(21 digital

data words)

i low-speed

data

(3-57 kc)

i low-speed

data

(182 cps)

3 dc power (regulated) i ac power

O_erational The major

(regulated,

filtered)

Characteristics operational

Binary,

characteristics

fixed-point,

of the computer_ are as follows:

stored-program,

general-purpose

8-77 CONFIDENTIAL

CONFIDENTIAL

PEMINI SEDR 300

Memo r_ Random-access, nondestructive-readout Flexible division between instruction and data storage 4096 addresses, 39 bits per address 13 bits per instruction word 26 bits per data word

Arithmetic Times Instruction cycle - 140 usec Divide requires 6 cycles Multiply requires 3 cycles All other instruction require i cycle each Other instructions can be progra=med concurrently with multiply and divide

Clock Rates Arithmetic bit rate - 500 kc Memory cycle rate - 250 kc

Controls and Indicators The computer itself contains no controls and indicators_ with the exception of the elapsed time indicator.

However, the computer can be controlled by means of four

switches located on the Pilots' Control and Display Panel:

a two-position

ON-OFF switch, a seven-position mode switch, a push-button START Computation switch, and a push-button RESET switch.

8-78 CONFIDENTIAL

CONFIDENTIAL

SYSTE_ OPerATION Power The computer IuertiR1 to

receives

Guidance

the

c_ater

the

System is

in regulation

source.

Actual and the

IGS Po_er

are

in the

for

transients

that

in

occur

operation

Power Unit.

from the

dc power

a manner that

in the

and depressions

Ccmlmter

its

The regulated

IGS Power Supply

interruptions

Auxiliary

required

Power Suppl_.

due to

power

Supply

(IGS)

buffered

any loss

Su_y

ac and dc power

eliminates

spacecraft

arel buffered

The power

supplied

inputs

prime

by the received

po_er

IGS Power from

the

as follows:

(a) 26 vacand return !-_.

(b)

+28 vdc filtered A_

return

(c) +27.2vdc andreturn (d)

-27.2 _e and return

(e)

+20 vde andreturn

(f)

+9.S "v_e_

The application

of all

Pilots'

Control

and IYispl_

e_sed

t_me indicator

the to

IGS Power Supply the

stops the

computer. operating

return

power

is

Panel.

starts by the

When the and the

controlled

_nen the

operating c_uter. s_r_teh

power

by the

control

l

switch

and a power This

is

0N-OFF switch

turned

signal off,

signal

is

is iturned control !

on the on,, the

sJj_ml

is

computer supplied

to

ca_es power to be transferred l the eCmlzlter elapsed time indicator [

l

terming=ted /

computer.

8-79 CONFIDENTIAL !

to

remove

pover

from

CONFIDENTIAL SEDR 300

PROJECT GEMINI Within the computer, the 26 vac power is used by magnetic modulators to convert de analog si_lals to ac analog signals.

This power is also used by a harmonic filter

to develop a 16 vac, _00 cps filtered gimbal angle resolver excitation signal. The +28 vdc power is used by computer power sequencing circuits.

The +27.2 vdc,

-27.2 vdc, +20 vdc, and +9-3 vdc power is used by power regulators to develop +25 vdc, - 25 vdc, and +8 vdc regulated power.

This regulated power is used by logic

circuits throughout the computer, and is supplied to some of the other spacecraft systems •

Basic Timin_ The basic computer timing is derived from an 8 mc oscillator.

The 8 mc signal is

counted down to generate four chock pulses (called W, X, Y, and Z) (Figure 8-21). These clock pulses are the basic t_m!ng pulses from which all other timing is generated.

The width of each chock pulse is O.375 usec and the pulse repetition

frequency is 500 kc.

The bit time is 2 usec, and a new bit time is considered as

starting each time the W clock pulse starts.

Eight gate signals (GI, G3, GS,

GT, @9, Gll, GI3, and Gl4) are generated, each lasting two bit times.

The first

and second bit times of a particular gate are discriminated by use of a control signal (called LA) which is on for odd bit times and off for even bit times. Fourteen bit times make up one phase time, resulting in a phase time length of 28 usec (Figure 8-22).

Five phases (PA through PE) are required to complete a

computer instruction cycle, resulting in an instruction cycle length of i_0 usec. Special phase timing, consisting of four phases (PHI through PHi) (Figure 8-23), is generated for use by the input processor and the output processor.

This timing

is independent of computer phase timing but is synchronized with computer bit timing.

8-80 CONFIDENTIAL

CONFIDENTIAL

PROJECT

GEMI

I I

"_

J-_-0.375USEC

wl-I

-'_

J"_--

rl__.R _

2USEC

I"1 I-1 I"1 n

I-1 n

r-i I-1 FL__R r'b

__n n n fln n n n run n n n n n rL n n n rb_n,n,n

n__n n =n n__n n n m

n n n rL_n__nno LAJ

I

r-'-I

r'--q

n nin

r'--!

i--1

J--

G,

I

G3

I

G5

n run

n,

I----i =J

28USEC

r

I,

I

I

I

I

G7

I

I

G_

i

I

I

G.

I

G,3

i

I

:

I

I I

G14 BIT TIMING

I

TABLE

BIT TIME (BT)

LA

GATE

BIT TIME (BT)

LA

GATE

I

"1"

G1

6

"0"

G7

11

"1"

Gll

2

"0"

G3

7

"1"

G7

12

"0"

GI3

3

"1"

G3

8

"O"

G9

13

"1"

G13

4

"0"

G5

9

"1"

G9

14

"0"

G1

5

'q"

G5

_6

"0"

G11

Clock

and

Figure

8-21

Computer

8-81 CONFIDENTIAL

BIT TIME (BT)

Bit

Timing

LA

GATE

CONFIDENTIAL

SEO

PROJECT

I_

28 USEC

GEMINI

i J

_,, n

n

_I

I

_

f

n

n

L I

_o

I

Figure

,,,,n

28 USEC

n_ I

I

_

n

8-22 Computer

I

Phase Timing

L [

n

_.,J

I

P.2

I

n

n

n

n_

I

b

I

_._

I

I

I I'

P.4-]

Figure

8-23 Processor

Phase

8-82 CONFIDENTIAL

Timing

I

CONFIDENTIAL

SEDR300

The computer

memory

nondestructive

is a random-access,

readout.

The nondestructive series-parallel, a separate

The basic

read property thereby

buffer

register.

bits.

A1! memory

words

each.

Data words

(25 bits

syllables,

Once the spacecraft modify

the third

syllables

makes

Data

accomplished

Insertion

in flight,

array

removed

Unit

arit_tic

into three

syllables

stored

word.

8 through

of data

System.

12, _sing

of 13 bits two syllables.

it is not possible

site through

Co_an_

or in

or 159,7_4

in all three

Modification

at the launch

core.

serially

in the first

area,

with

unit without

can store 4096 words,

are intermixed

or the Digital

on spacecraft

a serial

array

ferrite

to read or write

from the hangar

of any memory

ferrite

is! a two-hole

are normally

(13 bits)

0 and i can be accomplished

the Manual

with

are divided

and a sign)

has been

syllable

it possible

The memory

words

element

operation

of 39 bits

and instruction

coincident-current,

storage

allowing

i

stored

interface

to

in with

It can also be

the Auxiliary

Tape

Memory(A_). As

shown on Figure

readout

elements.

Z 8_mension),

with

8-2_, the memory Physically, each plane

is logically

subdivided

efficiency.

The Z d_mension

with

each

syllable

into

consisting

is a 64 x 64 x 39 bit array

it consists consisting smaller

of a stack

is divided

to increase

into three

of 13 bits.

(SEC O0 through

SEC 07, and SEC lO through

defined

as the residual

sector.

word

of the 4096 13 bits,

is defined

possible

and is coded

as the 39 bits

along

X-Y grid positions. in either

sMllables

syllable

word

8-83

SYL 2),

into 16

sector

17 being

and is located

at one

or co_-._nd requires

O, l, or 2 Of a memory

CONFIDENTIAL

storage

is divided

the Z dimension

in the

The memory

(SYL O through

SEC 17), with

An instruction

(stacked

of cores.

the program

The X-Y plane

sectors

A memory

of 39 planes

of a 64 x 64 array

parts

of nondestructive

word.

A data word

SYL 0

SYL2

J

CONFIDENTIAL

PROJE _@

SEDR300

requires 26 bits, and is always coded in syllables O and I of a memory word.

In-

formation stored in syllable 2 can be read as a short data word by using a special mode of operation primarily used to check the contents Of the memory.

NOTE The operation codes mentioned in the subsequent paragraphs are describe_ in the Instruction and Data Words paragraph.

Instruction List The instructions which can be executed by the computer are as follows:

f

O_eration Code 0000

Instruction HOPe

The contents of the memory location specified

by the operand address are used to change the next _nstruction address.

Four bits identify the next

sector, nine bits are transferred to the instruction address counter, two bits are used to condition the syllable register, and one bit is used to select one of the

0001

two data

DIV (divide).

word modes. ! The contents of the memory location

specified by the operand address are divided by the contents of the accumulator.

The 24-bit quotient is

available in the quotient delay line during the fifth word time following the DIV.

8-85 CONFIDENTIAL

CONFIDENTIAL

PROJEMINI SEDR300

o ration c, e (cout) 0010

z t ction PRO (process specified

input by the

or output). operand

(cont,),

The input

address

loaded from, the accumulator.

is

read

or output into,

or

An output co_and

clears

the accmnulator to zero if address bit A9 is a I. The accumulator

contents

are

retained

if A9 is

a O.

(Refer to Table 8-1 for a ]ist of the PRO instructions.)

O011

RSU (reverse subtract).

The contents of the accumula-

tor are subtracted from the contents of the specified memory location.

The result is retained in the ac-

cmnulat or.

0100

ADD.

The contents

of the

memory location specified

by the operand address are added to the contents of the accumulator.

The result is retained in the ac-

cumulator.

0101

SUB (subtract).

The contents of the memory location

specified by the operand address are subtracted fr_n the contents of the accumulator.

The result is re-

tained in the accumulator.

0110

CLA (clear and add).

The contents of the memory

location specified by the operand address are transferred to the accumulator.

8-86 CONFIDENTIAL

CONFIDENTIAL

PROJECT __

GEMINI

$EDR 300

!

Operand Address X (Bits AI-AB) Y (Bits A_-A6)

Signal

0

0

Digital C_._eJ_lSystem shift pulse gate

0

i

Data Tr_ssion

0

2

Time Reference System

System control gate data and timing

pulses 0

3

Digit magnitude weight I

0

_

Reset

0

5

Digit selec_ weight I

O

6

M_ory

i

0

Cumputer ready

I

i

Drive counters to zero

i

2

Enter

1

3

Digit

i

_

Display

i

5

Digit select weight 2

1

6

Autopilot scale factor

2

0

Pitch resolution

2

i

Select X counter

2

2

Aerospace

2

3

Digit

2

5

Digit select

2

6

Reset start _omputation

Table 8-1.

data

ready,

8-87

and readout

strobe

magnitude

we_ht

2

device drive

Ground Equipment data link

magnitude

PRO Instruction Progrmlng

CONI=IDINTIAL

enter,

weight

weight

(1 of 3)

CONFIDENTIAL

PRO,JEC--E'C-T-GEMINI _.

SEDR300 0perand X (Bits A1-A3)

Address Y (Bits A_-A6)

Signal

3

0

Yaw resolution

3

I

Select Y counter

3

2

Aerospace

3

3

Digitmagnitude weight8

3

_

Read Manual

3

6

Resetradarready

0

Roll resolution

i

Elapsed

4

Ground Equipment

data clock

Data Insertion

Unit

insert data

time

control

and Time Reference

System

control

reset/A_

wind-rewlnd

Reset 3

Computer

malfunction

_

ATM verify/repro

4

6

Secondstageenginecutoff

5

0

Computer

5

i

Time to start

command

_nning re-entry

/ATM wind

calculations

command

5

2

Time to reset

5

3

Write

5

4

Read

5

5

Inputprocessor time

5

6

Time to retrofirecontrol

6

3

Read pitch

6

4

Read roll

Table 8-1.

PRO Instruction

output

8-88 CONFIDENTIAL

control/ATM

rewind

processor

delta velocity

gimbal gimbal

Programming

control

(2 of 3)

command

CONFIDBNTIAL

__

SEDR300

Operand Address

Signal

x (_tsAI-A3) Y (Bits A4-A6) 6

5

Ready yaw gimbal

7

0

Pitch error comm_d

7

I

Yaw error c_,_ud

7

2

Roll error command i

I

I

Table 8-1.

PRO Instruction Prograr_4_g (3 of 3)

8-89 CONFIDENTIAL i

CONFIDENTIAL SEDR 300

PROJECT GEMINI

ope.,ration. Code (cont)_ 0111

Instruction (cont.). AND.

The contents of the memory location specified

by the operand address are logically ANDedj bitby-bit, with the

contents of the accumulator.

The

result is retained in the accumulator.

I000

MPY (multiply).

The contents of the memory loca-

tion specified by the operand address are multiplied by the contents of the accumulator.

The 24

high-order bits of the multiplier and miltiplicand are multiplied together to form a 26-bit product which is available in the product delay line during the second word time following the MPY.

iO01

TRA (transfer).

The operand address bits (AI

through AP) are transferred to the instruction address counter to form a new instruction address. The syllable and sector remain unchanged.

I010

SHF (shift).

The contents of _he accumulator are

shifted left or right, one or two places, as specified by the operand address, according to the following table:

8-90 CONI_II_I_NTIAI

CONFIDENTIAL

PRO

'

_.

!

SEDR300

Oweration Code (cont)

Instruction (cont) Co_and

Operand Address iX (Bits AI-A_) Y (Bits A4-A6)

Shift left one place

*

3

Shift left two places

*

4

Shift right one place

I

2

Shiftrighttwoplaces

0

2

• Insignificant

If an improp@r address co_e is given, the accumulator is cleared to zero.

While shifting left,

O's are shifted into the low-order positions; f

while shifting right, the Isign bit condition is i

shifted into the high-order positions.

1011

TMI (transfer on minus accumulator sign). i

If the

sign is positive (0), theinext instruction in i sequence is chosen (no branch).

If the sign is

negative (i), the nine bits of operand address become the next instructibn address (perform branch). The syllable and sector remain unchanged.

Ii00

STO (store).

The contents of the accummlator are

stored in the memory location specified by the ! I

operand address.

The con_ents of the accumulator I I

are also retained for later use.

8-91 CONFIDENTIAL

CONFIDENTIAL

code+(cont) ii01

stru,=t, ,o. (cont,) SPQ

(store product

available MI_.

o_ The

time

is

word

on the

The product location

an

fifth

word

or quotient

specified

(clear and add discrete). input

selected

by

read into all accumulator to Table

TNZ

followin6

is

is

by the

address.

discrete

iiii

The product

time

available

a DIV.

in the memory

operand

CLD

second

quotient

following

stored

iii0

the

or quotient).

accumulator

operand

address

bit positions.

on non-zero).

are zero,

is chosen

are non-zero, become

the

of the is

(Refer

8-2 for a list of the CLD instructions. )

(transfer

sequence

The state

the next

(no branch);

instruction

The syllable

of the

in

if the contents

the nine bits of operand

the next instruction

branch).

If the contents

address

address

(perform

and sector remnln

unchanged.

NOTE The instructions paragraphs

in the subsequent

(e.g., HOP, TRA, TMI,

are described Instruction

Instruction

mentioned

more

completely

Information

and TNZ)

in the

Flow paragraph.

Sequencing

The instruction

address

is derived

from an instruction

8-92 CONFIDENTIAL

counter

and its associated

CONFIDENTIAL

PROJEII __.@

SEDR300

OperandAddress X (Bits A1-A3) Y (Bits A4-A6)

Signal

0

0

Radarready

0

1

Computer mode2

0

2

Spare

0

3

Processor

0

4

Spare

1

0

Dataready

1

1

Computer mode1

1

2

Start

1

3

X zero indication

1

4

ATM clock

2

0

Enter

2

I

Instrumentation Systemsync

2

2

Velocityerrorcountnot zero

2

3

Aerospace

2

4

Spare

3

0

Readout

3

i

Computer

3

2

Spare

3

3

ATM on

3

11.

ATM data

0

Clear

Table

8-2.

CLD Instruction

timing

phase

computation

Ground

mode

Equipment

3

channel

2

Progr_-.._ug (I of 2)

8-93 CONFIDENTIAL

i

request

CONFIDENTIAL SEDR300

PMINI Operan& Address X (Bits AI-A3) Y (Bits A_-A6

Signal

1

A_

2

Simulation mode command

3

ATM end of tape

4

ATM data channel 3

5

0

Time to start re-entry calculations

5

i

ATM mode control 2

5

2

Y zero indication

5

3

ATM data 1

5

_

Spare

6

0

Digital Co;,_nd System ready

6

i

Fade-in discrete

6

2

Z zero indication

6

3

Umbilical disconnect

6

_

Spare

7

0

Instrumentation System request

7

i

Abort transfer

7

2

Aerospace Ground Equipment input data

7

3

Spare

7

_

Spare

Table 8-2.

mode control I

CLD Instruction Progrnmm_ng (2 of 2)

CONFIDENTIAL

4

CONFIDENTIAL

__

SEDR300

address register.

To address an instruction, the syllable_ sectorj end word

position within the sector (one of 256 positions) mus_ be defined.

The syllable

and sector are defined by the contents of the syllable register (two-bit code, three com_Luations) and sector register (four-bit code, 16 combinations). registers can be cha_ged only by a HGP instruction. sector is defined by the instruction _dress

These

The word position within the l

counter.

The instruction address

count is stored serially in a delay line; and normally each time it is used to address a new instruction, a one is added to it so th@t the instruction locations within a sector can be sequentially scanned.

The humor

stored in the counter can

be changed by either a TRA, TMI, or TNZ instruction, With the operand address specifying the new n,_ber.

A HOP instruction can alsO change the count_ with the

new instruction location coming from a data word.

Instruction and Data Word.s The instruction word consists of 13 bits and can be cOded in ar_ syllable of any memory word.

The four

The word is coded as follows :

Bit Positlon

i

Z

3

4

5

6

7

8

9

Bit Code

A1

A2

A3

A4

A5

A6

A7

A8

A90PI

operation

operand

address

presently

used,

rata residual.

bits bits

(OP1 through

(A1 through

and the

residual

OP4) define

AS) define bit

(Ag)

one

i0

II

12

13

OPe

OP30P4

_f 16 instructions,

a memory

_ord within

determines

_hether

the

or not

the sector to

read

eight being the

If the A9 bit is a i, the data word aSdressed is always located i

in the !eat sector (sector 17).

If the A9 bit is a O_ the data word addressed

i is ture

read

from the

allows

data

sector locations

defined to

by the be available

contents to

8-95 CONFIOENTIAL

of the i instructions

sector

register. stored

anywhere

This

fea-

in the

CONFIDENTIAL

The data word consists of 25 magnitude bits and a sign bit.

Nmnbers are represent-

ed in t_o's-complement form, with the lc_-order bits occurring at the beginning _f the word and the sign bit occurring after the highest-order bit. point is placed between bit positions 25 and 26. denotes the binary weight of the position.

The binary

The bit magnitude n-tuberalso

For example, MI6 represents 2-16.

For the HOP instruction, the next instruction address is coded in a data word that is read from the memory location specified _

the operand address of the HOP word.

The codings of a nmnerical data word and a HOP word are as follows :

Bit Position

i

2

S

4

5

6

7

8

9

i0

II

12

13

Data Word

M25

M25

M23

M22

_i

M20

MI9

MI8

MI7

MI6

MI5

MI4

MI3

HQP Word

AI

A2

AS

A4

A5

A6

A7

A8

A9

SI

$2

$3

$4

mt PgSlt±on IS 15 16 17

18 19 2o 21 z2 23 e_ 25 26

Data Word

MI2

M8

H_ Word

-

MII

MIO

M9

_.A S'ZB

M7

)46

M5

MS

MS

M2

MI

S

....

s5

For the HOP word, eight address bits (AI through A8) select the next instruction (one of 256) within the new sector, the residual bit (Ag) determines whether or not the next instruction is located in the residual sector, the sector bits (SI through $4) select the new sector, and the syllable bits (SYA and SYB) select the new syllable according

to the following

S_able

table :

,_B

S_A

0

0

0

1

0

1

2

I

0

CONFIDENTIAL.

-

CONFIDENTIAL

_.

PROJENI

Roll

and yaw servo loops utilize

gyro outputs.

Inner

resolvers

roll and yaw gimbals

to correl_te are controlled

gimbal

angles with

by a coordinate

i

transformation

resolver

is at any pitch

mounted

attitude

other

on the pitch than

gimbal.

When

0 or 180 degrees_

the spacecraft

some roll motion

is

=

sensed by the yaw gyro and some yaw motion amount

of roll motion

gimbal

angle.

The resolver

output

is then

conditioned

drive

is sensed by the roll gyro.

sensed by the yaw gyro is proportional mounted

on the pitch

in the same manner

gimbal

The

to the pitch

angle.

as in the pitch

Resolver servo

loop to

inner roll and yaw gimbals.

The outer roll gimbal coordinate

transformation

the Anzle between than 90 degrees conditioned

inner

_

outer roll servo loop. platform

housing

from the inner

mounted

is produced

(phase

The outer

and moves

If the angle

resolver.

sensitive

roll gimbal

about the stable

electronics)

torque Imotor i

element

other

The error

servo Iloop to drive

A

monitors

is a_hing

by the resolver.

as in the pitch

circuit

roll gimbal

i on the irLUer roll gimbal,

roll a_d yaw gimbals.

error signal

additional

driven

resolver

in the same manner

One

gimbal.

is servo

signal

the outer

is incluced

is mounted

is

roll

in the

on the

with the spacecraft.

As

i

the spacecraft gimbal Phase

torque

moves through motor must

sensitive

for control. the yaw axis.

90 degrees

rotate

electronics

The resolver

in yaw, the direction

to compensate

and a resolver

As the gimbal

rotates

for sp;acecraft roll,

provide

is used to measure through

8-65 CON|=IDENTIAL

that the outer

the phase

reverses.

reversal

necessary

rotatilon of the yaw gimbal i 90 degrees

in yaw,

roll

about

the resolver

CONFIDENTIAL

PRO

M IN I SEDR 300

output changes phase.

Resolver output is compared to a reference phase by the

phase sensitive electronics.

When the resolver output changes phase, the torque

motor drive signal is reversed.

Pre-Launch Alignment

The IMU is the inertial reference for back-up ascent guidance and must therefore be aligned for that purpose. launch azimuth.

The platform is aligned to local vertical and the

Platform X and Y accelerometers are the reference for local

vertical alignment.

When the platform is aligned to the local vertical, X and Y

accelerometers are level and cannot sense any acceleration due to gravity.

If

any acceleration is sensed, the platform is not properly aligned and must be torqued until no error signal exists.

The accelerom_ter output is used by AGE

equipment to generate torque signals for the gyros.

When the gyro is torqued

it produces an error signal which is used to align the gimbal.

The outer roll

g_mhal synchro output is compared with a signal representing the launch azimuth by AGE equipment.

The error signal is conditioned by AGE equipment and applied

to the yaw gyro torque generator.

The yaw gyro signal generator then produces a

signal proportional to the input torque. resolver mounted on the pitch gimbal.

Gyro output is coordinated by a

Since the spacecraft is in a 90 degree

pitch up attitude essentially all of the yaw gyro output is transferred to roll gimbal control electronics.

The electronics drive the roll gimbals until no

error exists between synchro output and the AGE reference signal. signal exists, the platform is aligned to the launch azimuth.

8-66 CONFIDENTIAL

When no error

CONFIDENTIAL

PROJEI

O_ItAlig_e_

_1_gnment of the platform in orbit is accomplished by referencing it to the horizon sensors.

Placing the platform mode selector £n SEF or ]_F position

will reference it to the horizon sensors.

Pitch and roll horizon sensor outputs

are compared with platform pitch and outer roll synchro outputs.

Differential

amplifiers produce torque control signals proportional to the difference between sensor and synchro outputs.

Torque control signals are used to drive pitch and

roll gyro torque 6enerators.

Gyro signal generator o_tputs are then used by

gimbal control electronics to dri_,_platform gimbals.

When synchro and horizon

sensor outputs balance, the pitch and roll gimbals are aligned to the local verti. i

cal.

The yaw gimbal is aligned to

the orbit plane through a @yro compass loop.

If yaw errors exist, the roll @yro will sense a component of orbit rate.

The

roll @yro output is used through a _Fro compass loop _o torque the yaw _ro. Yaw gyro output is then used by gAmbal control electronics to drive the yaw i gimbal.

When the roll gyro no longer senses a component of orbit rate, the yaw

gimbal is aligned to the orbit plane.

All three gimbals are now aligned and will

remain aligned as long as SEF or BEF modes are used.

!The pitch gyro will be

continuously torqued (at the orbit rate) to maintain a horizontal attitude.

NOTE If

horizon

platform

sensors is

lose

track

w_'.le

in SEF or _RF modes,

the

the

platform is automaticallp switched to ORB RA_

mode.

8-67 CONFIDENTIAL

CONFIDENTIAL

PROJECT

Orbit

Rate Circuit

The orbit rate durin@

circuit

attitude

with

four degrees

Local

because

per minute.

vertical

they will

no external

is obtained

amplifier. rate.

is used to ,_intain

orbit maneuvers.

during maneuvers

TOrque

GEMINI

alig_nent

cannot be provided

lose track.

reference,

the pitch

The torque

represents

by placing

The bias drives

to the local

Orbit rate bias is adjustable

at approximately

the spacecraft

8Yro torquer

sensors

a horizontal

is torqued

a DC bias on the output

the pitch

by horizon

TO maintain gyro

vertical

orbit

of the pitch

differential

at approximately

and can be set to match

rate.

the orbit

orbits

of various

altitudes.

Phase

Angle Shift Technique

Phase

Ar_le Shift Technique

ability.

One of the factors

unbalance.

which affects

The effect of unbalance

on with the synchronous different

(PAST) is a method

point

motor's

will vary with field.

each time It is started.

Drift

errors by a factor

of spin motor

8Yro drift

rotating

are in the order of O. 5 degrees drift

of improving

excitation

per hour.

of ten.

30 degrees

drift

Drifts

now tend to cancel and become predictable.

compensation

circuits.

gyro torque

generator.

for. )

All three

The drift Drift

point

e_,_rs t PAST

compensation

compensation

circuits

torques

848 CONFIDENTIAL

controX

unbBIAnce

the phase

is shifted.

is predictable

loops

apply

on to a

of reducing

Shifting

(_nen drift

of lock

shifts the phase

each time the phase

8yro torque

rotor

can lock

a means

at re_p_lar intervals.

repeat-

in the point

errors due to rotor

the rotor to lock on a different

compensated

changes

The spin motor

causes

it can be

is spin motor

PAST provides

TO cancel

gyro drift

contain

drift

a dc bias to each

the 8Yro in the opposite

....

CONFIDENTIAL

PROJECT _.

GEMINI

SEDR300

direction as predictable drift, maintaining a stable attitude.

Attitude

Malfunction

Detection

i An attitude malfunction generator

excitation,

voltages.

detection

glmbal control

Gyro signal generator

amplitude.

circuit performs

se_f checks of gyro signal i logic timing signals, and critical

signals,

excitation

is checked for presence and proper

Gimbal control signals are checked for th( length of time signals

are present.

The logic timing signal (28.8kc) is che(_ed for presence.

cal voltages (+22vdc, -3vdc, +12vdc) are checked for tion is detected,

,resence.

Criti-

If a malfunc-

an ATT light on the control panel is automatically

illuminated.

If momentary malfunctions occur, the ATT indicator cam be restored to normal operation

by pressing the RESET button.

NOTE If the attitude measurement malfunction,

the acceleration

tions are not reliable.

circuits indica-

Accelerometer

axes will not be properly alignedland indications are along _n_uown axes.

Acceleration

Measurement

Acceleration is measured along three mutually perpendicular axes of the inertial platform.

Sensing devices are three miniature pendulOus accelerometers.

8-69 CONFIDENTIAL

The

CONFIDENTIAL

PROJEC'T

GEMINI

accelerometers are mounted in the platform pitch block and measure acceleration along gyro x, y, and z axes.

Accelerometer

signal generators produce signals

whose phase is a function of the direction of acceleration. output is used to control torque rebalance pulses.

Signal generator

The torque rebalance pulses

drive accelerometer pendulums toward their null position.

Rebalance pulses are

dc current whose polarity is controlled by signal generator output.

The polarity

of rebalance pulses indicates the direction of acceleration and the algebraic sum of the pulses indicates the amount of acceleration.

Rebalance pulses are

supplied to the spacecraft digital computer where they are used for computations and incremental velocity displays.

Torque

Rebalance

Loop

Three electrically identical torque rebalance loops are used to control accelerometer pendulum positions.

Normally an analog loop would be used for this pur-

pose; however, if an analog loop were used, the output would have to be converted to digital form for use in the computer.

To eliminate the need for an analog to

digital converter, a pulse rebalance loop is used.

Short duration 184 milliampere

dc current pulses drive the accelerometer pendulum in one direction until it passes through null.

Pulses are applied at the rate of 3.6kc.

passes through null, signal generator output changes phase.

When the pendulum

The signal generator

output is demodulated to determine the direction of the pendulum from null. Demodulator output is used by logic circuits to control the polarity of rebalance pulses.

If acceleration is being sensed, there will be more pulses of one polar-

ity than the other.

If no acceleration is being sensed, the number of pulses of

8-70

CONFIDENTIAL

CONFIDENTIAL

_.

SEDR300

each polarity will be equal.

In addition to controlling the polarity of rebalance

pulses, logic circuits set up precision timing of the pulses. !

Precision frequency

inputs from the timing circuits are the basis for rebalance pulse t_m_ng.

Precise

timing is essential because the amount of pendulum torgue depends on the length of the current pulse.

All pulses are precisely the sar_ duration and amplitude,

therefore total torque is dependent only on the algebraic sum of the applied pulses.

Each time a reba]ence pulse is applied to the accelerometer torquer, a

pulse is also provided to the computer.

Algebraic su_=_tion of the rebalance

pulses is performed by the computer.

Pulse

Rebalance

Current

Supply

A pulse rebalanee current supply provides the required current for torque rebalance.

Since acceleration

measurements

are based on the number of torque pulses i

it is essential that all pulses be as near identical as possible. stable current, a ne_tive

feedback circuit is employed.

To maintain a

The supply output is

passed through a precision resistor and the voltage drop across the resistor compared to a precision voltage reference. Errors detected by the comparison are i used in the feedback circuit to correct any deviations enhance

in current. To further

stability both the current supply and the precision

are housed in a temperature

controlled

voltage reference

oven.

Accelerometer Dither

A pendulous aecelerometer, unlike a gyrp, has an inherent mass unbalance. mass unbalance is necessary to obtain the pendul,]maction.

The

Due to the unbalance,

perfect flotation of the pendulous glmbal cannot be achieved and consequently

8-71 CONFIDENTIAL

CONFIDENTIAL m_mmmmq

PROJECT _.

SEDR3O0

pressure

is present

caused by bearing

on the gimbal

friction,

The oscillation

(dither)

enough

stiction.

to cause

a i00 cps dither imposed

prevents

signal and adc

dither

signal beats against

down.

The dither motion

Accelerometer

pulses

gimbal

field

the stlction

oscillation

is imposed

from resting oscillation,

current.

is applied

to a separate

the dc field,

causing

the output

on its bearing

The dc field

and creates

a magnetic

coil.

the glmbal to oscillate axis and consequently

detection

and critical

voltage.

circuit

performs

Incremental

self checks

up and

no motion

velocity

pulses

from each of

it indicates

a flip flop did not reset

between

critical

voltage

is checked

If a malfunction

that

(+12 vdc)

an ACC light on the control

for presence.

panel is automatically

the accelerometer

by pressing

If pulses are absent

of incremental

seconds,

operation

The

Detection

for presence.

normal

around

generator.

malfunction

occur,

is super-

field

(modulator)

long

are required:

current

the three axes are checked

malfunctions

effect,

on the g_mbal.

two signals

excitation

is not around

Malfunction

acceleration

velocity

signal

To minimize

the gimbal

To obtain

The I00 cps dither

is sensed by the

bearing.

a low amplitude

on the signal generator

the gimbal.

An

GEMINI

malfunction

the RESET

button.

of the accelerometer

does not affect

attitude

8-72 CONFIDENTIAL

circuits

measurements.

The

is detected,

If momentary

can be restored

NOTE Malfunction

than 0.35

set pulses.

illuminated. circuit

longer

to

--

CONFIDENTIAL SEDR 300

PROJECT

AUXILIARY

COM_

The Auxiliary power

POWER UNIT

Computer

supply

properly

voltages

(ACPU)

can cause permanent are provided

at the computer.

The first circuit

control

circuit.

The second

circuit

and the third is auxiliary ON-OFF

Tr-nsient

power

as a transient

che_es

in the ACPU

at the computer.

is a trsnaient

circuit

senSe

The ACTU

memory.

_ low voltage

is a low voltage

power.

The computer

or a depression.

in the computer

to prevent

the IGS

Three

condition

and auxiliary

_ense

and power

is turned

power control

on and off with

switch.

sense circuit

conditions.

is designed

A series type

If regulator

voltage

the transient

sense circuit

The regulator

then places

the desired

level.

Low Volta_e

Sense

A low volta6e

craft bus volta6e

detects

auxiliary

regulator

c_uter

volta@e

drops

i below

the drop and turns power

transient

voltage

supply

momentarily

and correct

holds

low auxiliary

regulator

a minimum

of 17.5 volts,

on the series

on the line land mlntains

voltage

regulator. voltage

at

Circuit

sense

the computer

to sense

transistor

off the line as long as IGS power

is normal.

When

either

with

Sense Circuit

The transient volta@e

is used in eo_Junction

dc voltages

on low voltage

types of circuits

the C_

"-

Power Unit

to realntain the correct

cannot function Abnormal

GEMIN

circuit

is turned

prevents

the computer

on, the low volta@e

is above 21 volts

before

from operating

sense icircuit insures

a!l_lir_pOwer

8-73 CONFIDENTIAL

on low voltage. that

to be applied

space-

to the

GONFIDENTIAL

PROJECT

computer.

If the computer

is already

the transient

sense circuit

If spacecraft

bus voltage

voltage power

sense circuit

is controlled

on when

will maintain

is not back

initiates

through

GEMINI

normal

to normal

a controlled

contacts

sense circuit

the relay.

of the relay initiate

identical turns

with the computer

off the computer

voltage

sense.

attempt

to maintain

normal voltage

If power were

normal voltage

the auxiliary

Power

Auxiliary

power consists

cadmium

low voltage

battery

of i00 milliseconds charge

and rectifier.

to ac.

The ac voltage

limiting

to 25 milliamperes. source

and a trickle

will

A trickle

The charger

former,

a current

The battery

or less.

on the battery.

dc by a full wave

would

consists

The oscillator is then

stepped

diode rectifier. resistor,

in a manner

sense

circuit

charger.

of a transistor

a transformer

if desired.

8-74 CONFIDENTIAL.

it would

to maintain

A O. 5 ampere-hour

during

is provided

spacecraft

to maintain

a full

oscillator, supply

the battery

trans-

dc voltage

and changed

limits

bus

for periods

is then applied,

The resistor

to charge

low

be exceeded.

power

output

circuit

except

In attempting

up with

is included

sense

circuits

static power

Rectifier

circuit.

it deenergizes

shutdown

changes

to the battery.

Provision

depression

Computer

sense

supply up to 9.8 amperes

charger

the low

of the computer.

to the transient

is used to supply computer

transients.

i00 milliseconds

to all ACPU

power capability

occurs,

for lO0 milliseconds.

When the low voltage

at the computer.

of a battery

condition

in the low voltage

a computer

power

not broken

after

a voltage

power switch.

it also breaks

Auxiliar_

nickel

detects

voltage

shutdown

of a relay

When the low voltage Contacts

a low voltage

back

to

through

charging

current

from an external

CONFIDENTIAl.

_@

SEDR 300

DIGITAL

COMPUTER

SYSTEM DESCRIPTION

General The Digital

Computer,

point#

stored-program,

tions.

The computer

deep.

It weighs

Figure

8-20.

hereinafter

referred

general-purpose is 18.90

inches

58.98 pounds.

The major

computer, high,

External

external

to as the computer,

used to perform

i_.50

views

is a Binary,

inches wide,

and 12.75

of the computer

characteristics

on-hoard

fixed-

computa-

inches

are shown

in

are s_t-_arized in the accompany-

in6 legend.

Using _.

inputs

computer

performs

catch-up, puter

from other

along

the computations

required

during

back-up

and re-entry guidance

phases

with

a stored

thei: pre-launch,

of the mission.

for the Bunch

program,

the

insertion,

In addition,

the com-

vehicl(

during

ascent.

Platform_

System

Electronics,

and Outputs

The computer Inertial Manual

systems,

rendezvous,

provides

Y_ts

spacecraft

is interfaced

Guidance

Data

Attitude

System

Insertion

Display,

Auxiliary

with the Inertial

Power

Unit,

Attitude

Tape Memory

Supply,

Auxiliary

Time Reference Control

(spacecraft

System,

and Maneuver 8 through

Computer

Power

Digital

C_and

Electronics,

12), PiloSs'

Unit, System,

Titan Autopilot,

Control

and Display

!

Panel, Ground outputs

Incremental Equipment. include

Velocity

Indicator,

In connection

with

Instrumentatio_ these

System,

l interfaceS,

the following:

Inputs i _0 discrete 3 incremental

velocity

8-V5 CONFIDRNTIAL i

and Aerospace

the computer

inputs

and

CONFIDENTIAL

LEGEND ITEM

- -"

NOMENCLATURE

Q

MOUNTING

ACCESS COVER

(_

CONNECTOR

J4

Q

CONNECTOR

J5

(_

CONNECTOR

J7

CONNECTOR

J3

CONNECTORJR

Q

CONNECTOR

(_

CONNECTOR J6

(_

MOUNTING

ACCESS COVER

(_

MOUNTING

ACCESS COVER

MOUNTING

ACCESS COVER

)

JI

ELAPSED EIME INDICATOR CONNECTOR

(_)

RELIEF VALVE

(_

I'_OUNTING

(_

HANDLE

(_

MOUNTING

ACCESS COVER

ACCESS COVER

"_

ACCESS COVER

IDENTIFICATION

_

MAIN

PLATE

ACCESS COVER

BUS BAR ACCESS COVER (_

BUS BAR ACCESS COVER

(_

RELIEFVALVE II

Figure 8-20 Digital Computer 8-76 CONFIDENTIAL

CONFIDENTIAL

PRO SEDR 300

Inputs

i

(cont)

3 gimbal

angle

2 high-speed

data

(500 kc)

i low-speed

data

(3.57 kc)

i low-speed

data

(182 cps)

i input

and read-back

(99 words)

6 dc power

(5 regulated,

i ac power

(regulated)

i unregulated)

Outputs 30 discrete i--

3 steering

command

3 incremental I decimal

display

(7 digits)

i telemetry

(21 digital

i low-speed

data

i low-speed

data (182 cps)

data words)

(3.57 kc)

3 dc power

(regulated)

i ac power

(regulated,

Operational The major

velocity

filtered)

Characteristics operational

Binary,

characteristics

fixed-point,

of the computer

stored-program,

_re as follows:

general-purpose

f

8-77 CON FIDENTIAL.

CONFIDENTIAL SEDR300

PROJECT GEMINI Memo r_ Random-access, nondestructive-readout Flexible division between instruction and data storage 4096 addresses, 39 bits per address 13 bits per instruction word 26 bits per data word

Arithmetic Times Instruction cycle - 140 usec Divide requires 6 cycles Multiply requires 3 cycles All other instruction require I cycle each Other instructions can be progrn..nedconcurrently with multiply and divide

Clock tes Arithmetic bit rate - 500 kc Memory cycle rate - 250 kc

Controls

and Indicators

The computer itself contains no controls and indicators, with the exception of the elapsed time indicator.

However, the computer can be controlled by means of four

switches located on the Pilots' Control and Display Panel: ON-OFF switch, a seven-position and a push-button

mode

switch, a push-button

RESET switch.

8-78 CONFIDI.rNTIAL

a two-position START Computation

switch,

CONFIDENTIAL

;_

PROJECT

GEMINI

SYSTEM 0PE%_TION

The computer

receives

the

ac and dc I_wer

required

for

its

operation

from the

The regulated dc power supplied

Inertial Guidance System (IGS) Power Supply.

to the computer is buffered in the IGS Power Supply in a manner that eliminates any loss in regulation due to transients that occur in %he spacecraft prime power source.

Actual power interruptions and depressions areibuffered by the IGS Power

Supply and the Auxiliary Ccm_uter Power Unit.

The power inputs received from the

IGS Power Suppl7 are as follows:

(a)

26 vac and return

(b)

+28 vdc filtered and return

(e)

+27.2 wle A-d return

(d)

-27.2 _c

Ce)

+20 vdc and return

(f)

+9.3 _e an_return

and return

The applieatlon of all power is controlled by the ON-0FF switch on the Pilots'

Control

elapsed

time

the to

indicator

IGS Power Supply the

stops the

and Displ_

eom_uter. operating

Panel.

starts by the

When the and the

When the

operating computer. s_rltch

power

is

control

switch

and a power This turned

signal off,

signal

is

is iturned cox trol ca_les

the

eompute_.

8-79 CONFIDENTIAL .....

stKnal power

e, mputer

termi_Lted

i

on_ the

to

is

computer supplied

to

be tr.n-ferred

elapsed

time

to remove

power

indicator from

CONFIDENTIAL

PROJECT GEMINI

Within the computer, the 26 vac power is used by magnetic modulators to convert dc analog signals to ac analog signals.

This power is also used by a harmonic filter

to develop a 16 vac, _00 cps filtered gimbal angle resolver excitation signal. The +28 vdc power is used by computer power sequencing circuits.

The +27.2 vdc,

-27.2 vdc, +20 vdc, and +9.3 vdc power is used by power regulators to develop +25 vdc, - 25 vdc, and +8 vdc regulated power.

This regulated power is used by logic

circuits throughout the computer, and is supplied to some of the other spacecraft systems •

Basic Timln_ The basic computer timing is derived from an 8 mc oscillator.

The 8 mc signal is

counted down to generate four clock pulses (called W, X, Y, and Z) (Figure 8-21). These clock pulses are the basic timing pulses from which all other timing is generated.

The width of each clock pulse is 0.375 usec and the pulse repetition

frequency is 500 kc.

The bit time is 2 usec_ and a new bit time is considered as

starting each time the W clock pulse starts.

Eight gate signals (Gl, G3, GS,

GT, Gg, GII, GI3, and Gl_) are generated, each lasting two bit times.

The first

and second bit times of a particular gate are discriminated by use of a control signal (called LA) which is on for odd bit times and off for even bit times. Fourteen bit tlmes make up one phase time, resulting in a phase time length of 28 usec (Figure 8-22).

Five phases (PA through PE) are required to camplete a

computer instruction cycle, resulting in an instruction cycle length of 140 usec. Special phase tlmlng, consisting of four phases (PHI through PHi) (Figure 8-23), is generated for use by the input processor and the output processor.

Thls timing

is independent of computer phase timing but is synchronized with computer bit timing.

8-80 CONFIDENTIAL

CONFIDENTIAL

s o 3oo

PROJECT

GEMINI

!

--_ _- o.37B USEC

--"1

[-----2USEC

wn n n n n n_n

n n n n n n FUJI n_

x_n n n n n rL_n n n__n n n n,n I"I

n

I"I ,,I-I I-L_FI

,,_

n

n

I

G_

I

G5

rl.__R

rl

II

n

n

I-

n,, n n n n n n!run n n n 28USEC

!=

G_

i-I

n rE

:

-I

! I

I

I

:

I

I

G7

I

G,

I

! I

:

I

I I

G,, G,3

I i

I

GI,

I I

BIT TIMING BIT TIME (BT)

LA

GATE

BIT TIME (BT)

1

Iili'

G1

6

II0'1

G7

2

"0"

G3

7

"1"

3

"1"

G3

8

"0"

¢

5

_IOII

"I"

Figure

G5

G5

_

10

8-21 Computer

I

TABLE LA

Ill

GATE

"

"0"

_JT TIME (BT)

CONFIDENTIAL

GATE

I'1"

Gll

G7

1'2

"0"

GI3

G9

13

"1"

G13

]4

1'0"

G_

Gll

Clock and Bit :Timing 8-81

LA

lj

G_

l

CONFIDENTIAL

_

s,=oR 300

i"

BT'4 El

28 USEC



I

R

P_ I

1

_

I

n

n

I I

I



I

Figure

_,,,n

28 USEC

rb I

_

I •

n

8-22 Computer

I

Phase Timing

I_l

n

_.,J

I

_._

I

n

n

n

n_

I

S

I

_H_

r-

I'

I

_ -I

I'

Figure

8-23 Processor

Phase Timing

8-82 CONFIDENTIAL

I

CONFIDENTIAL

_.

SEDR300

Me:o_ The computer

memory

nondestructive

is a random-access,

readout.

The nondestructive

read

The basic property

series-para_ _el, thereby a separate

buffer

bits.

_1! memory

words

each.

Data words

(25 bits

syllables,

modify

the thir_

syllables

makes

Data

accomplished

Insertion

in flight,

array

and a sign)

can store

_096 words,

into three

syllables

Stored

with

ferrite

toi read or write i

core.

serially unit

or in

without

or 159,7_4 of 13 hits

in the first

are intermixed

word.

in all three

Mod/flcation

two syllables.

of data stored

i

at the launch

or the Digital

on spacecraft

isi a two-hole

array

from the hangar iarea, it is not possible

of any memory

Unit

ferrite

a serial arithmetic

are normally

(13 hits)

O and i can he accomplished

the Manual

with

are divided

has been removed

syllable

it possible

The memory

words

element

operation

of 39 bits

and instruction

Once the spacecraft

storage

allowing

register.

coincident-current, i

site through

C_nd

8 through

System.

12, using

to

in

interface

with

It can also be

the Auxiliary

Tape

emory As

shown on Figure

readout

elements.

8-24, the memory Physically_

is a 64 x 64 x 39 bit array

it consists

of nondestructive

of a stack of 39 planes

(stacked

in the

I

Z dimension),

with

each plane

is logically

subdivided

efficiency.

The Z dimension

with each

syllable

into

consisting

consisting smaller

of a 64 x 6_ array

parts

is divided

to increase

into three

of 13 bits.

of cores.

the program

syllables

The X-Y plane

The memory

storage

(SYL 0 through

is divided

SYL 2),

into 16

i

sectors

(HEC O0 through

SEC 07, and SEC i0 through

defined

as the residual

sector.

A memory

word

is defined

as the 39 bits

along

SEC 17), with

the Z ilmenslon

sector

17 being

and is located

at one

!

of the _096 13 hits,

possible

X-Y grid positions.

and is coded in either

An instrucSion

syllable

word

or command

O, I, or 2 Of a memory J

8-83 CONFIDENTIAL

word.

requires

A data word

CONFIDENTIAL SEDR 300

0

y

32

40

skt o

15

11f

11 ,---

Sp_ !

Figure

8-24

Computer

Memory 8-8i4

CONFIDENTIAL

Functional

Organization

CONFIDENTIAL SEDR 300

PROJECT

GEMIN

requires 26 bits, and is always coded in syllables 0 and I of a memory word. Ini formation stored in syllable 2 can be read as a short data word by using a special mode of operation primarily used to check the contents of the memory.

_0TE The operation codes mentioned in the subsequent paragraphs are described in the Instruction and Data Words paragraph.

I truction

Ist

The instructions which can be executed by the computer are as follows: !

._

O_eration ,Code 0000

ilnstruction HOP.

The contents of t_e memory location specified iI

by the

operand

address

instruction address.

are

used

to

change

the

next

FQur bits identify the next i

sector, nine bits are transferred to the instruction address counter, two bi_s are used to condition the syllable register, and one bit is used to select one of the

o001

two data

DIV (divide).

word modes.

The contents

of the

memory location

specified by the operandi address are divided by the i

contents of the accumulator.

The 24-bit quotient is

i

available in the quotient del_y line during the fifth i word time following the DXV.

8-85 CONFIDENTIAL

i

I

CONFIDENTIAL

PROJEMINI _.

SEDR300

O_eration 0010

Code(cont)

(cont)

Instruction PRO (process specified

input by the

or output). operand

The input

address

loaded fr_n, the accumulator.

is

read

or output into,

or

An output command clears

the accumulator to zero if address bit A9 is a i. The accumulator contents are retained if A9 is a O. (Refer to Table 8-1 for a llst of the PRO instructions.)

0011

RSU (reverse subtract).

The contents of the accumula-

tor are subtracted from the contents of the specified memory location.

The result is retained in the ac-

cu_ulator.

0100

ADD.

The contents of the memory location specified

by the operand address are added to the contents of the accumulator.

The result is retained in the ac-

cumulator.

0101

SUB (subtract).

The contents of the memory location

specified by the operand address are subtracted from the contents of the accumulator.

The result is re-

tained in the accmnulator.

0110

CLA (clear and add).

The contents of the memory

location specified by the operand address are transferred to the accumulator.

8-86 CONFIDENTIAL

CONFIDENTIAL

PROJECT ___

GEMI

SEDR 300

_erand X (Bits A1-AS) 0

Address Y (Bits A_-A6) 0

Signal

Digital Cum_nd i

System shift pulse gate

i

0

i

Data Transmission System control gate i

0

2

_me

Reference System data and timing pulsesi

p-

0

3

Digit magnitude weight I

0

1_

Reset

0

5

Digit select weight I

0

6

Memory strobe

1

O

C_put

I

i

Drive counters to zero

I

2

Enter

i

3

Digit magnitude

i

_

Display device

i

5

Digit select weight 2

i

6

Au_opilot scale factor

2

0

Pitch resol_ion

2

i

Select X counter

2

2

Aerospace

2

3

Digit

2

5

Digit selec_ weight

2

6

Reset start !computation

Table 8-1.

data

er

ready,

8-87

and readout

ready

we_t

2

drive

Oround Equipment data link

magnitude

PRO Instruction Progrvm_ng

CONFIDENTIAL

enter,

weight

(i of 3)

CONFIDENTIAL

PROJEMINI SEDR 300 Operand A_ress X (Bits AI-A3) Y (Bits A_-A6)

Signal

3

O

Yaw resolution

3

i

Select Y counter

3

2

Aerospace Ground Equipment data clock

3

3

Digitmagnitude weight8

3

_

Read Manual Data Insertion Unit insert data

3

6

Reset radar ready

4

0

Roll resolution

4

i

Elapsed time control and Time Reference System control reset/A_

wind-rewind

Reset 4

3

Computer malfunction

_

ATM verify/repro command

6

Second stage engine cutoff

5

0

Computer x.m_ing

5

1

Time to startre-entrycalculations control /ATM wind co_and

5

2

Time to reset control/ATM rewind command

5

3

Write output processor

5

4

Readdelta velocity

5

5

Inputprocessor time

5

6

Timeto retrofire control

6

3

Read pitch gimbal

6

4

Readrollgimbal

Table 8-1.

PRO Instruction Programming (2 of 3)

8-88 CONFIDENTIAL

CONFIDENTIAL

_.

SEDR 300

Operand Address X (Bits AI-A3) X BitsA4-A6)

_

Signal

6

5

Ready yaw glm_al

7

0

Pitcherror Co.m_nd

7

i

Yaw error command

7

2

Roll

Table 8-1.

error c_nd

PRO Instruction Programm4!ug(3 of 3)

8-89 CON

FIDUNTIAL

CONFIDENTIAL

,%_-_

SEDR300

___

Operation COde (cont) 0111

Instruction (cont) AND.

The contents of the memory location specified

by the operand address are logically ANDed, bitby-bit, with the contents of the accumulator.

The

result is retained in the accumulator.

I000

MPY (multiply).

The contents of the memory loca-

tion specified by the operand address are multiplied by the contents of the accumulator.

The 24

high-order bits of the multiplier and miltiplicand are multiplied together to form a 26-bit product which is available in the product delay line during the second word time following the MPY.

i001

TRA (transfer).

The operand address bits (AI

through Ag) are transferred to the instruction address counter to form a new instruction address. The syllable and sector remain unchanged.

i010

SHF (shift).

The contents of _he accumulator are

shifted left or right, one or two places, as specified by the operand address, according to the following table :

8-90 CONPIDIEN'rlAL

CONFIDENTIAL

s.)t

i i

O_eration Code _ont)

Instruction (cont) Command

O_erandAddress iX (Bits AI-A_) Y (_BitsAM-A6)

Shift left one place

*

3

Shift left two places

*

4

Shift right one place

i

2

Shiftrighttwoplaces

0

2

• Insignificant

If an improp@r address co_e is given, the accumui lator is cleared to zero. While shifting left, O's are shifted into the Low-order positions; while shifting right, theisign bit condition is shifted into the high-order positions.

i011

_I

(transfer on minus a_cumulator sign).

If the

sign is positive (9)_ the next instruction in i sequence is chosen (no b_anch). If the sign is negative (i), the nine b_ts of operand address become the next Instruction address (perform branch). i The syllable an_ sector remaln unchanged.

Ii00

STO (store).

The contents of the accumulator are f

stored in the memory location specified, by the ! 1 operand address. The co_tents of the accumulator are also retained for la1_eruse.

8-91 CONFIDIENTIAL.

CONFIDENTIAL

PROJECT

GEMINI

Si:DR 300

o tlm,

code+(cont)

str, uctl,m ,(era, +,,) SI_ (store

Ii01

product

available _Y.

or

on the

second

quotient

is

The

time following

IIi0

CLD

time

available

The product

an

fifth

word

or quotient

specified

(clear and add discrete). input

selected

is

by the

to Table

accumulator

bit positions.

on non-zero).

are zero,

is chosen

are non-zero, become

address

is

(Refer

8-2 for a list of the CLD instructions. )

(transfer

sequence

The state of the

by the operand

read into all accumulator

TNZ

following on the

location

is

address.

discrete

iiii

The product

word

a DIV.

stored in the memory operand

quotient).

the next

(no branch);

instruction

The syllable

of the

in

if the contents

the nine bits of operand

the next instruction

branch).

If the contents

address

and sector

address

(perform

remain

unchanged.

NOTE The instructions paragraphs

mentioned

in the subsequent

(e.g., HOP, TRA, TMI, and TNZ)

are described Instruction

more

completely

Information

in the

Flow paragraph.

I nstructio n Sequencing The instruction

address

is derived

from an instruction

8-92 CONFIDENTIAL

counter

and its associated

CONFIDENTIAL.

PROJEI __.

SEDR 300

0perand Address X (Bits AI-A3) Y (Bits A4-A6)

_

Signal

0

0

Radar ready

0

1

Computer mode2

0

2

Spare

0

3

Processor timing phase i

0

_

Spare

i

0

Data ready

I

i

Computer modei

i

2

Start computation

I

3

X zero indication

1

4

ATM clock

2

0

Enter

2

i

Instrumentation System sync

2

2

Velocity error count not zero

2

3

Aerospace Ground Equil_nentrequest

2

4

Spare

3

0

Readout

3

i

Computer mode 3

3

2

Spare

3

3

ATM on

3

h

A_4 data channel 2

0

Clear

Table 8-2.

CLD Instruction Progrs..._ng (i of 2)

8-93 CON FIDENTIAL

CONFIDENTIAL

Operand Address X (Bits AI-A3) Y (Bits A4-A6)

Signal

1

A_

2

Simulation

3

ATM end of "tape

4

ATM data channel

5

0

Time

5

i

ATM mode

5

2

Y zero indication

5

3

A_ deta 1

5

_

Spare

6

0

Digital

Command

6

i

Fade-in

discrete

6

2

Z zero indication

6

3

Umbilieal

6

_

Spare

7

0

Instrumentation

7

i

Abort

7

2

Aerospace

7

3

Spare

7

_

Spare

4

Table

8-2.

mode

CLD Instruction

CON I=IDENTIAL

control mode

to start

1 co._aand

3

re-entry

control

calculations

2

System

ready _--

disconnect

System request

transfer Ground

progrsmm_ng

Equil_nent input

(2 of 2)

data

CONFIDENTIAL

PNI

address register.

,o,,oo

i

To address an instruction, the syllable, sector, and word

position within the sector (one of 256 positions) must be defined. and sector

are defined

by the

contents

of the

The syllable

syllabl

e register (t_o-bit code, i three combinations) and sector register (four-bit code, 16 combinations). These registers can be cha_ged only by a HGP instruction. sector is defined by the instruction _dress

The word position within the

counter.

The instruction address

count is stored serially in a delay line; and normally each time it is used to address a new instruction, a one is added to it so that the instruction locations within a sector can be sequentially scanned.

The number stored in the counter can

be changed by either a TRA, TMI_ or TNZ instruction, With the operand address specifying the new n,_her.

A HOP instruction can alsO change the count, with the

new instruction location coming from a data word.

Instruction and Data Words The instruction word consists of 13 bits and can be coded in any syllable of any m_nory word.

The word is coded as follows :

Bit Position

l

2

3

4

5

6

7

8

9

Bit Code

AI

A2

AS

A4

A5

A6

A7

AS!A9

i0

Ii

12

GPI

OP20PS

13 OP4

The four operation bits (0PI thro,_h 0P4) define one iof16 instructions, the eight e_erand address bits (AI through AS) define a memory _ord within the sector being presentl_ used, and the residual bit (Ag) determines whether or not to read the data _esidual.

If the A9 bit is a i, the data word addressed is always located

in the last sector (sector 17). F

If the A9 bit is a 0, the data word addressed

is read from _he sector defined by the contents of the sector register. ture alloss data

locations to be available

to

instru(tions

8-95 CONIWIOIKNl"lAI. i

stored

anywhere

This feain the

CONFIDENTIAL

SEDR 300

The data

of 25 man,rude

word consists

ed in t_o's-complement _f the point

ward is

denotes

and the

placed the

form, sign

between

binary

with

bit bit

the

of the

and a sign

low-order

occurring positions

weight

bits

after

the

2_ and 26.

position.

bits

bit.

Numbers

occu_,;ing

highest-order The bit

For example,

at

are

the

represent-

beginning

bit.

The binary

magnitude

number also

M16 represents

2 -16.

For the HC_ instruction, the next instruction address is coded in a data word that is read from the memory location specified by the operand address of the HOP word. The codings of a nmmerical data word and a HOP word are as follows :

BitP, ositloni

2

3

_

5

6

7

8

9

1o

11

12

13

Data Word

M25

M24

M23

M22

M21

M20

MI9

MI8

MI7

MI6

MI5

MI4

MI3

HOP Word

AI

A2

A3

A4

A5

A6

A7

A8

A9

Sl

S2

S3

S4

Bit Positic_

14

15

16

17

18

19

20

21

22

23

2_

25

26

Data Word

MI2

MII

MIO

M9

M8

M7

M6

M5

M4

M3

_

MI

S

SYA

SYB

-

S5

HOP Word

.......

For the HOP word, eight address bits (AI through A8) select the next instruction (one of 256) within the new sector, the residual bit (A9) determines whether or not the next instruction is located in the residual sector, the sector bits (SI through $4) select the new sector, and the syllable bits (SYA and SYB) select the new syllable according to the following table :

S_Uab,le

_B

sYA

0

0

0

i

0

i

2

I

0

8-96 CONFIDENTIAL.

_-

CONFIDENTIAL

PRO __

SEDR300

The special syllable bit ($5) determines the mode in which data words are to be read.

If the $5 bit is a 0, normal operation of reading data words from sylI

lables 0 and 1 is followed; however, if the $5 bit is a l, data words are read from syllable 2 only.

These data words contain infoE_tion

from syllable 2 in

bit positions 1 through 13, but contain all O's in bi_ positions 14 through 26. This special mode is foISowed until a new HOP c_and the normal mode of reading data words.

places the computer back in

(While in the ispecial mode, amy HOP word

addressed always has O's coded in the SYA_ SYB, and $5 positions due to the short data word that is read; therefore,

any HOP word!coded

while in this mode

terminates the mode and operation is resumed In syllable 0.).

The computer itself

i

does not have the capability to store information in Syllable 2; therefore, ST0 i and SPQ commands are not executed while in the special mode. The mode Is used ;

only to allow the computer arithmetic circuits to check the entire memory contents i to verify the fact that the proper information is in storage.

In a HOP word, the residual bit (A9) overrides the sector bits (S1 through S_). If the A9 hit Is a l, the next instruction is read frOm the residual sector.

If,

however, the A9 bit is a 0, the S1 through $4 blts determine the sector from which the next instruction is read.

For convenience, the data and instruction words can be coded in an octal form that is easily converted to the machine hlnary representat$on.

The order in which the

bits are written is reversed to conform to the normal imethod of placing lowersignificance blts to the left so that, while perform_pg arithmetic, the low-order bits are accessed first.)

The coding structure Is as follows:

8-97 CONFIDENTIAL

CONIFIDISNTIAL

PROJECT

GEMINI

_SEDR

300

____

Instruction Word 0Ph

OP3

0F2

0P1

A9

AB

A7

A6

A5

A4

A3

*Y Address

A2

A1

*X Address

*Addresses for CLD and PRO instructions

Data Word

s

_I

M2

M3

M4

M5

M6.......... M20

N21

M22

.23

M24 N25

where each group of three bits is expressed as an octal character (from 0 to 7). An instruction word is thus expressed as a five-character octal number.

The opera-

tion code can take on values from 00 to 17, and the operand address can take on

777. Any operand address larger than 377 addresses the residual

values from 000 to

sector (sector 17) because the highest-order address bit (Ag) is also the residual identification bit.

A data word is expressed as a nine-character octal number,

taking on values from 000000000 to 777777776.

The low-order character can take on

only the values of O, 2, 4, and 6.

Arithmetic Elements The computer has two arithmetic elements: and a multiply-divide element.

an add-subtract element (accumulator),

Each element operates independently of the other;

however, both are serviced by the same program control circuits.

Computer oper-

ation times can be conveniently defined as a number of cycles, where a cycle time represents the time required to perform an addition (140 usec).

All operations

except MPY and DIV require one cycle; MPY requires three cycles, and DIV requires six cycles.

Each cycle, the program control is capable of servicing one of the

arithmetic elements with an instruction.

An MPY or a DIV instruction essentially

starts an operation in the multiply-divide element, and the program control must

8-98 CONFIDINTIAL

CONFIDENTIAL

PROJECT

GEMINI

obtain the answer at the proper time since the multlply-divide element has no means of completing an operation by itself.

When an MPY is co_m_nded, the

product is obtainable from the multlply-dlvide element two cycle times later by an SPQ instruction.

When a DIV is commanded, the quotient is obtainable five

cycle times later by an SPQ instruction.

It is possible to have one other instruction run concurrently between the MPY and the SPQ during multiply, and four other instructions run concurrently between the DIV and the SPQ during divide.

However, an MPY or a DIV is always followed with an

SPQ before a new MPY or DIV is given.

Basic Information

Flow

Refer to Figure 8-25 for the following description of _nformation flow during the i five computer phase times.

The description

is l_m4tedl to those operations I

requir-

ing only one cycle time, and thus does not pertain to MPY and DIV. i During phnse A, the 13-bit instruction word is read from memory and stored in the instruction address register.

The address of the instruction is defined by the

contents of the memory address register, the sector r_gister, and the sy11-ble register.

The four operation code bits (OP1 through 0P4) are stored in the

operation register.

During phase B, the operand address bits (AI through AS) are

seri-1:lytransferred from the instruction address register to the memory address l register.

S_,,_Itaneously,the instruction address stored in the memory address

register is incremented by plus one and stored in the iinstruction address register. The operation specified by the operation code bits is !performed during phases C and D.

During phase E, the next instruction address Stored in the instruction

address register is transferred to the m_ory

8-99 CONFIDENTIAL

address register.

CONFIDENTIAL

PROJECT ,,

GEMINI

'=.,

_J

D

X DRIVERS

REGISTER

Y D MEMORY

R I

PHASE B (INSTRUCTION ADDRESS)

E

• INSTRUCTION ADDRESS

REGISTER

PHASES C & D

MEMORY ADDRESS

!'

J_ J REGISTER j _PHASE B (OPER AND ADDRESS) PHASE E (INSTRUCTION ADDRESS)

i _ !

i

OPERATION REGISTER

SENSE AND INHIBIT DRIVERS

REGISTER PHASE

J

SYLLABLE

J

1

PHASE C&D

[ Figure

l

8-25

Basic

Information 8-100

CONFIDENTIAL

T Flow

OUTPUTS

J

CONFIDENTIAL $EDR 300

Four of the one-cycle operations do not strictly adhere to the above information flow.

These operations are HOP, TRA, T_I, and _FZ.

For the HOP instruction, data

read from memory during phases C and D is transferred directly to the instruction address register, the sector register, and the syll,ble register.

For the TRA,

S_I, and TNZ operations, the transfer of the next instruction address from the instruction address register during phase E is inb_bited to allow the operand address to become the next instruction address.

Instruction Information Flow Flow Diagram:

The instruction information flow diagram (Figure 8-26) should be

used along with the following descriptions.

CLA Operation During phases C and D, the data that was contained in the accumulator A and B is destroyed.

S_multaneously,

during phases

new data from the selected memory location

is transferred through the sense amplifiers and into the ace_tor. i

During

phases E and A, the new data is recirculated so as to be available in the accumulator during phases A and B.

ADD Operation During phases C and D, new data from the selected m_ry through the sense amplifiers

and into the accumulator_

location is transferred Here, the new data is

added to the data that was contained in the acctamulator during phases A and B. During phases E and A, the sum data is recirculated sO as to be available in the accumulator

during phases A and B.

SUB Operation During phases C and D, new data from the selected memory location is transferred

8-iOl CONFIDENTIAL

CONFIDENTIAL SEDR 300

"TRA" ACCUMULATOR SIGN CONTROL

DRIVERS

_

.oP

,N.IS,T

Y

R I V

_

MEMORY _

S

HOI

"TRA"

HOP _

a

TNZ TMI ACCUMULATOR



PRO

(16

r

INSTRUCTIONS) --

INSTRUCTION

t OR

TIME)

A_

m

_I =

(OPERATE __

ADD

--I

(ADD-SUBTRACT

-

|

i

INPUT PRO _ OUTPUT ADDRESS _

IN%:T£_T_ = PRO

_ _

(OP_RATETI_E)

l

NOTE A---- AND;

Figure

m OUTPUT DATA

8-26

I --- INVERTER

Instruction 8-102 CONFIDENTIAL

Information

Flow

CONFIDENTIAL SEDR 300

PROJECT

GEMINI

through the sense amplifiers and into the accumulator.! Here, the new data is subtracted from the data that was contained in the accumulator durlngphases and B.

A

During phases E and A, the difference data is recirculated so as to be

available in the accumulator duringphases

A and B.

RSU Operation Duringphases

C and D, new data from the selected memory location is transferred

through the sense amplifiers and into the accumulator.! Here, the data that was contained in the accumulator during phases A and B is isubtracted from the new data.

Duringphases

E and A, the difference data is recirculated so as to be

available in the accumulator during phases A and B.

AND Operation During phases C and D, new data from the selected memory location is transferred through the sense amplifiers and into the accumulator_

Here, the new data is

ANDed with the data that was contained in the accumulator during phases A and B.

i During phases E and A, the ANDed data is reelrculatedlso as to be available in the accumulator during phases A and B.

SHF Operation During phases C and D, the data that was contained inithe ac_tor

during

phases A and B is shifted left or right, one or two places, as specified by the operand address.

During phases E and A, the shifted _ta

is recirculated so as

to be available in the accumulator during phases A an_ B.

f

STO Operation During phases C and D, the data that was contained inithe phases A and B is transferred thr_sh

accumulator during

the inhibit drivers and stored in the memory

8-lO3 ¢ONPIDENTIAL

CONFIDENTIAL

PROJECT

location

selected

reeirculated

by the

operand

address.

so as to be available

in the

GEMINI

During

__

phases

accumulator

E and A, the

during

phases

same data

is

A and B.

H0P Operation During

phases

C and D, new data

from the

selected

memory location

is

transferred

through the sense --_lifiers and into the address, sector, and syllable registers. Here, the new data is used to select the address, sector, and syllable of the memory location from which the next instruction will be read.

TRA Operation During phases A and B, the instruction from the selected memory location is transferred through the sense an_lifiers and into the address register.

Here, the

instruction is ttsedto select the address of the m_zory location from which the next instruction will be read.

The sector and syl1.ble remain unchanged.

TMI Operation During phases A and B, the instruction from the selected memory location is transferred thro_,_hthe sense amplifiers and into the address register.

Here, if the

accumulator sign is negative, the instruction is used to select the address of the memory location from which the next instruction will be read.

However, if the

acc_._lator sign is positive, the next instruction address in sequence is selected in the normal m_nner.

The sector and syllable remain unchanged.

TNZ Operation During phases A and B, the instruction from the selected memory location is transferred through the sense A_lifiers

and into the address register.

Here, if the

contents of the accumulator are not zero, the instruction is used to select the address of the memory location from which the next instruction will be read.

8-1o4 CONFIDENTIAL

.....

CONFIDENTIAL

PR FNI _.

SEDR300

However,

if the contents

in sequence

of the accumulator

is selected

in the normal

are zero

manner.

The

the next instruction

s@ctor and syllable

address

remain

un-

changed.

CLD Operation During

phases

C and D, the data that was contained

A and B is destroyed. the operand

address

Simultaneously, is transferred

phases E and A, the new data lator during

the state

in the accumulator

of the discrete

into all accumulator

is reeirculated

during

input

bit positions.

so as to be available

phases

selected

by

During

in the accumu-

phases A and B.

PRO Operation

(Inputs;

During

phases

C and D, the data that was contained

phases

A and B is destroyed.

by the operand

address

when A_I)

Simultaneously,

is transferred

the new data is recirculated

in the accumulator

during

the data on the input

into the accumulator.

so as to be available

channel

During

phases

in the accumulator

selected E and A,

during

i

phases

A and

B.

PRO Operation

(Inputs; when

During

C and D, the data on the input

phases

transferred

Ag=O)

into the accumulator.

Here,

channel

selected

the new data

by the operand

is ORed with

is

the data that

i

was contained ORed data

in the accumulator

is recirculatad

during

phases

so as to be available

A and B.

During

phases

in the accumulator

E and A, the

during

phases

A

and B.

.

PRO Operation

(Outl_tS)

During

C and D, the data that was contained

phases

A end B is tr_sferred

to the output

channel

in the accumulator

selected

8-I05 CONFIDENTIAL

:

by the operand

during

phases

address.

If

CONFIDENTIAL

PROJECT

GEMINI

the A9 bit of the operand address is a i, the data that _¢as contained in the accumulator during phases A and B is then destroyed.

However, if the A9 bit is

a 0, the data is reclrculated so as to be available in the accumulator during phases A and B.

MPY Operation During phases A and B of the first instruction cycle, the data that is contained in the accumulator is transferred into the multiply-divide element as the multiplier.

During phases C and D of the same cycle, new data from the selected

memory location is transferred through the sense amplifiers and into the multiplydivide element as the multiplicand.

During the remainder of the first instruction

cycle and the next tw_ instruction cycles, the multiplicand is multiplied by the multiplier.

The product is available in the multiply-divide element during phases

C and D of the third instruction cycle.

DIV Operation During phases A and B of the first instruction cycle, the data that is contained in the accumulator is transferred into the multiply-divide element as the divisor. During phases C and D of the same cycle, new data from the selected memory address is transferred through the sense amplifiers and into the multiply-divide element as the dividend.

During the remainder of the first instruction cycle and the next

five instruction cycles, the dividend is divided by the divisor.

The quotient is

available in the multiply-divide element during phases C and D of the sixth instruction cycle.

8-106 CONFIDINTIAL

....

CONFIDENTIAL.

__

SEDR300

SPQ Operation During phases C and D, the product or quotient that is contained in the multiplydivide element is transferred through the inhibit dr_vers and stored in the memory location selected by the operand address.

In the subsequent program and interface descriptions, the signals that are

pro-

grammed by CLD and PRO instructions are sometimes referred to as DI (Discrete i

Input) or DO (Discrete Output)isignals. I

The two digits

following

the

DI or DO

are the Y and X addresses, respectively, of the instructions.

OPERATIONAL PROGRAM

General Two different programs are used with the rendezvous configuration of the spacecraft.

For spacecraft 6, the sixth operational program is utilized.

craft 8 and up, the seventh operational program is used.

For space-

The primary difference

between the two is that the latter is a modular program and is used in conjunction with the Auxiliary Tape Memory (ATM).

Sixth Operational

Program

The sixth operational program consists of six basic routines, called executor, pre-launch, ascent, catch-up, rendezvous, and re-entry. of several subroutines.

Eech routine is made up

Some of the subroutines are common to all routines while

8-io7 CONFIDENTIAL.

CONFIDENTIAL

PROJECT

GEMINI

SEDR300

SODIe are l__n4_queto a particular of pros_m

instructions

to operate.

which,

The initiation

PUTER mode

switch

initiated,

the subroutines

Executor

dividual

when

Each

executed,

of a particular

on the Pilots'

Control

within

subroutine cause

specific

routine

Panel.

are executed

of a series

computer

is controlled

and Display

the routine

consists

circuits

by the CCM-

Once a routine

is

automatically.

Routine

The executor routines.

routine.

routine

selects,

The program blocks

(a)

and handles

the functions

flow for this routine

is shown on Figure

shown on the figure are explained

Block

1.

co-_on to, all other

When the computer

8-27.

as follows:

is turned

on, the first memory

tion addressed is address 000, sector 00, syllable O. location routine

(b)

is the first memory

The operational

locations

dresses.

addresses

on whether

instructions

utilized

This memory

by the executor

computer

scale factor,

utilizes

special

as Logical

predetermined

Choice

(LC) ad-

the sign bits at these LC addresses

(0).

The sign bits

during

the execution

of specific of the

they are plus or minus,

are

The following

computation, pilot

times,

are then checked

of program

3.

program

are designed

(I) or plus

and, depending

Block

which

At certain

are set minus

(c)

address

loca-



Block 2. memory

The in-

LC

routines

special

series

executed.

discrete

running,

AGE data

8-i08 CONFIDENTIAL

outputs

second

clock,

are set plus:

stage

engine

start

cutoff,

and Time Reference

auto-

System

gate.

CONFIDENTIAL SEDR 300

1 LC ADDRESSES

' I

TIME

YES

TIME

I

NO

YES

i

I

REiD C)

I

,r

Figure

8-27

r

I

EXECUTE ASCENT

EXECUTE CAICCH -Ul

ROUTINE

ROITINE

Executor

Routine

Program

8-109 CONFIDENTIAL

!

Flow

O

CONFIDENTIAL

PROJECT

(d)

Block 4.

The processor

the individual

(e)

Block

5-

Block

The accelerometer

6.

A special

determine

If these

this

Program

instruction

subroutine

signals

is executed

the GO path

causes

program

arithmetic

fail,

instruction

to verify

from the accelerometers

computer

circuits

there is no failure,

Block 7.

is read for utilization

go, no-go diagnostic

if the basic

properly.

(g)

real time count

by

routines.

the X, Y and Z velocity

(f)

GEMINI

that

equal

is executed

circuits

zero.

to

are functioning

the NO GO path is followed;

if

is followed.

PR03_

is executed.

the computer

malfunction

The execution circuit

of

to be con-

ditioned.

(h)

Block 8.

The processor

utilization

(i)

real time count

by the individual

Block 9-

Program

condition

of the AGE request

for

routines.

instruction

l, the YES path is followed;

is read and updated

C_ID32 is executed discrete

input.

to determine

If the input

the

is a

if the input is a O, the NO path

is followed.

(J)

Block

i0.

Special

check-out

the Gemini T.aunch Vehicle

(k)

Blocks

II through

determine mode

i_.

the condition

switch.

This

tests are executed

and the computer

Program

instructions

of the discrete

switch is manually

8-110 CONFIDm'NTIAL

by the AGE.

can be checked

CLDIO,

inputs

controlled

CLDII,

Both

out.

and CLDI3

frcm the CCMPb_/_ by the pilot and,

CONFIDENTIAL

SEDR 300

depending routine

upon which

until

to the

mode is

be execute_ cce_uter

is

mode switch

discrete

routtne

as follows.

are

selected,

until

the

turned

off.

inputs

icauses

switcl

is

The combinations

required

Routine

setting

a particular

t(

select

changed

or

of COMPUTER

a particular

Discrete Inputs i

Pre-launch

0

0

0

Ascent

1

0

0

Catch-up

i

0

i

Rendezvous

0

1

0

Re -entry

0

1

1

(i)

Blocks 15 through 19.

Depending on the setting of the COMPUTER

mode switch, one of these operationaliroutines is selected. l ;i individual routines are discussed in Subsequent paragraphs.

The

Pre-launchRoutine The pre-launch routine provides the instructions required to check out the com! i

purer prior to launch and to read in special data forifuture use. This routine i performs sum-checks on all sectors within the computer memory. These checks are |i

performed by adding the contents of all memory addresses within a sector and i comparing

the sum with a pre-stored constant.

If theiconstant and the sum are ;

not equal, the computer malfunction latch is set by program instruction PR03_. If the sum check is successful, special data is store@ in predetermined memory addresses hythe

co--nonsubroutines.

These subroutines are discussed in later

paragraphs. 8-iii CONFIDENTIAL

CONFIDENTIAL

PROJ E'-E'C"T-G-EM I N I SEDR 300

Ascent

Routine

The ascent routine provides the computations required for back-up ascent guidance. After the computer has been placed in the ascent mode, special data is transferred to the computer via the Digital Command System.

This data is then continually up-

dated and used to keep track of the orbit plane and the platform attitude with respect to Earth.

Thirty second_ after the special data is first transferred to

the c_nputer, the Inertial Guidance System is placed in the inertial mode. computer continually this time.

monitors

The

and stores the platform gimbal angle values during

After lift-off, the co_puter performs a back-up guidance function.

If necessary, however, the computer can he used to perform prlmary guidance during ascent.

Catch-up Routine The catch-up routine provides the computations required to properly position the spacecraft for rendezvousing.

During the catch-up mode, gimbal angle values and

incremental velocity values are computed.

Calculated data is then supplied to

the Attitude Display so that the spacecraft can be properly positioned for rendezvousing.

Rendezvous Routine The rendezvous routine provides the computations required for achieving a rendezvcus.

The routine performs essentially the same function as the catch-up routine,

with the addition of radar data computations.

The radar data is transferred to

the conjurer from the rendezvous radar and utilizc_lin computations.

These compu-

tations are used to achieve a rendezvous between the spacecraft and the target.

Re-entry Routine The re-entry routine provides the computations required for re-entry guidance. 8-112 CONFID'rNTIAL

CONFIDENTIAL

SEDR 300

During

the re-entry

velocity respect

errors

mode, the retrograde

are calculated.

to the desired

landing

velocity

The distance

is monitored

and heading

site are calculated,

and retro_rade

of the spacecraft

a_d the down

with

range travel

to

i

touchdown craft

is predicted.

roll

maneuvers

The routine

during

also provides

re-entry

signA]_

and provides

to com_ana

a d_aplay

of

the space-

attitude

errors.

NOTE The following previously

subroutines

described

accelerometer, mentation

a description

Gimbal

Angle

The glmbal

angle

subroutine

cessing

operation

than

System,

angle, Instru-

Therefore,

subroutines

follows.

Platform.

the glmbal

During angle

value

axis were

the processing angle

glmbal

value.

for the pitch,

a computer word

time,

and transfers

This method

for each

angles

enables

processed,

the

a previously

a faster

pro-

individually.

of lone gimbal angle

value

(The igimbal angle value

and

is the

angle. )

Subroutine

Unit.

subroutine These

spacecraft,

adjustment

between

of the actual

The acceleremeter

of the

and processes

if the angle

of the next gimbal

equivalent

Measuring

reads

reads in one gimbal

5 ms elapses

the processing

Accelerometer

gimbal

data.

of each of these

angle value to the acc_-mllator.

Approximately

binary

and manual

of the Inertial

angle processor

read glmbal

Command

to the

Subroutine

yaw, and roll axes glmbal

routines:

Digital

System,

are co_nn

processes

signals,

are generated

of the accelerometers,

which

velocity represent

signal

velocity

by accelerometers. the signals

8-i13 CONFIDENTIAL

inputs

contain

Due

from the Inertial

for the X, Y_ and Z axes to the construction

inherent

bias

and

and alignment

CONFIDENTIAL

PROJECT

GEMINI

__

SEDR300

errors. values

The

subroutine

corrects

in predeterm_ued

the X, Y, and Z velocity

line.

The delay line ,is then

depend

on the selected

Co,_and

The Digital Digital

Co._and

Co,_nd

consisting

where

the data bits

then

signals,

locations.

read by the subroutine

System subroutine (DCS).

of 6 address

reads

input processor

them to the processor at periodic

The data bits

bits

intervals

in the computer

this

stored

data furnished

the computer with

and 18 data bits.

from the DCS.

are then

After

and processes

The DCS furnishes

are to be stored

bits.

velocity

delay which

or routine.

if data is available

by the address

The computer

and transfers

reads the data into the ac_1,.,lator.

separated.

and stores the corrected

Subroutine

System

wor_s

determines

mede

System

errors

computer memory

reads

Digital

these

The address memory.

special bits

the address

in the computer

data is stored,

24-bit

indicate

The subroutine

If data is available,

Next,

by the

first

the subroutine

and data bits are

memory

address

it is used as constants

specified by other

subroutines.

The DCS subroutine (Address

100-117).

operational tendsd

program

address

accomplished first

recognized address words

contains

it is necessary order

and the associated With

order

the DCS extended

20 first,

low order

address,

into the computer.

8-ll CONFIDENTIAL

the proper

and this must be

21 next).

20 is recognized

On the second

DCS addresses.

For each DCS ex-

two transmissions

address

data yields

extended

in the computer.

to make

data.

provide

20 and 21 exercises

(i.e., DCS address

the DCS subroutine,

is stored as high

which

of addresses

loops to store the data

in the proper

word.

instructions

The recognition

insert,

cycle through

ciated data

also

and the asso-

cycle, address

data plus

it is possible

On the

21 is

the DCS extended to insert

26-bit

CONFIDENTIAL

PRO SEDR3OO

Instrumentation

System

Subroutine

The Instrumentation

System

the Instrumentation

System.

to the Instrumentation the stored include pitch,

velocity roll,

mentation words

results

of other

address

in the Instrumentation mentation

MAnual

21 data words

for the X, Y, and Z axes,

input

are assembled

Once

occurs.

in a special

of 21 predetermined

as a word System

selection

memory

the input

values

seconds,

for the

the Instru-

occurs,

the data

System

addresses.

tO determine

are

transferred

l_strumentation

memory

counter

buffer

angle

every 2.4

When

data words

of data words gimbal

it to

are transferred

The transferred

The types

range.

data and transfers

A special

which

are to be transferred

memory

data words

to the Instru-

System.

Data

The manual

Subroutine data

Data Keyboard Readout

subroutines.

consists

is used

special

by the subroutine.

sync discrete

The buffer

assembles

2._ seconds,

and yaw axes, and radar

to be transferred

memory

Every

System

changes

System

buffer.

subroutine

subroutine

determines

(MDK) to the computer

(MDR).

The subroutine

are used to govern

when

and from the computer i

consists

the generation

data is transferred

of approximately

of signals

that

control

from the Manual

to the Manual

Data

I000 instructions circuit

operation

which in

the MDK and MDR.

Seventh

Operational

The seventh

Program

operational

program

craft 8 and 9 are scheduled to use all six modules. discussed I

Module

I represents

of six modules.

to use modules

Each module

below and under Sixth

Module

consists

that portion

I, IV and V.

contains

,Operational

certain

At this time, Spacecraft

routines

space-

i0 is scheduled

and subroutines

' Prog_.

of the program 8-115 CONFIDENTIAL

which

is always

maintained

in

as

CONFIDENTIAL

PROJECT--GEMINI SEDR 300

the computer memory.

It contains the programming required for the pre-launch

mode as well as that associated with the executer functions,

diagnostic

sub-

routines, computational subroutines and the ATM read programs.

Module II Module II consists of the ascent computer mode, a simplified catch-up mode (no radar interface) and that portion of the re-entry mode required for ascent/abort re-entry guidance.

For ascent/abort re-entry, the computer mode selector remains

in ASC.

Module III Module III consists of the catch-up and rendezvous modes as described under Sixth Operational

Program.

Module IV Module IV contains the touchdown predict and re-entry modes.

The touchdown

predict mode provides an on-board capability for predicting the half-llft touchdown point on the basis of ground-computed orbital initial condition data and a selected trial retrograde time.

The calculated time-to-go to retrograde and

the associated retrograde initial conditions may be automatically transferred to the Time Reference System (TRS) and re-entry program, respectively, for subsequent initialization of the re-entry mode.

The re-entry mode is generally

the same as that described for the Sixth Operational Program.

Module V Module V contains the ascent mode of module II, without the ascent/abort capability, and the catch-up and rendezvous modes of module III without the rendevous self test.

The purpose of modnle V is to insure that ATM load failure

8-116 OONFIDIENTIAL

CONFIDENTIAL

SEDIt 3OO

will

not

Jeopardize

Module

VI

Module

VI contains

completion

of rendezvous

the orbit predict,

mission

orbit

objectives.

navigation,

and orbit

determination

tootles.

The orbit predict position

mode

provides

of the spacecraft

position)

as much

This mode

also provides

in the spacecraft inputs

the capability

or target

as three orbits

The orbit navigation

axes while

velocity

and position

computer

equations

provides

changes

or 0ne orbit i

by

to

the orbit

computation

the means

including

the velocity

relative

s_,,_late _isive i is accomplished by accepting

This

mode

(or thei_

into the future

the capability

orbit.

in the guidance

vehicle

to calculate

and

velocity

and

into the past.

velocity

changes

velocity

change

is not in progress.

to navigate il

the spacecraft

the accelerometer

outputs

during

in the

of motion.

The orbit determination

mode

provides

the capability

to improve

the on-board

i

navigation star

to

accuracy

local

by processing

vel'q_icle

angle

the measurements

taken

aboard

the

of! star to horizon

angle

or

spacecraft.

I_I'I_WACE S Figure also

8-28

shows the equipment

contains

references

which

interfaces

to the individual

with

equipment

the computer. interface

The diagram

diagrams.

i

InertialPlatform (Figure8-29) The computer on the pitch, rotors

supplies roll,

_00 cps excitation

and yaw gimbal

of any of these

resolvers

to the rotors

axes of the !nertial

away from their

of three Platform.

resolvers

Movement

zero! (platform-caged) i

8-117 CONFIDENTIAL.

i

located of the

reference

CONFIDENTIAL SEDR 300

__.

4,

PROJECT

GEMINI

INERTIAL MEASURING

PLATFORM (FIGURE 8-29)

UNIT

ELECTRONICS (FIGURE 8-30)

POWER SUPPLY (FIGURE 8-31)

J

N IMENTAL

VELOCITY INDICATOR (FIGURE 8-40)

:

-'-

AEIOSACE GROUND EQUIPMENT (FIGURE 8-42)

I

TITAN AUTOPILOT



I

DIGITAL

_

(FIGURE 8-37)

_=

_

_

COMPUTER

IPLOT I CONTROL AND DISPLAY PANEL (FIGURE 8-39)

!

NI

I

I ...

SYSTEM (FIGURE 8-41)

DIGITAL COM/CU_,ND SYSTEM (FIGURE 8-34)

i NDEzv°us .

IT ISY ME E EM

(FIGURE 8-38)

(FIGURE 8-33)

IA TUDECONT I OL I AND MANEUVER ELECTRON] CS

I

_=

(FIGURE 8-36)

NOTE []_

i

SPACECRAFT 8 THRU 12 ONLY.

Figure

8-28

READOUT

KEYBOARD

(FIGURE 8-32)

(FIGURE 8-32)

MANUAL

Computer 8-118

CONFIDENTIAL

DATA INSERTION

Interfaces

UNIT

I

C_ AUXI LIARY TAPE MEMORY (FIGURE 8-38)

I

CONFIDENTIAL SEDR 300

j_

_L___._'_

PROJECT

GEMINI

! INERTIAL PLATFORM

_

DIGITAL

COMPUTER

I

RETURN (XCEGAEG)

ROLL GIMBAL

ANGLE

FILTER

(XPR4PPSRRC)

REFERENCE (XPR4PCRPRC)

YAW GIMBAL

ANGLE

l

(XPR3PPSRVC) GIMBAL ANGLE

REFERENCE (XPR3PCRPYC)

PITCH GIMBAL ANGLE



PROCESSOR

(XPR1PPSRPC)

REFERENCE (XPR1PCRPPC)

J ACCELEROMETER

-X VELOCITY

Y

PLATFORM

ACCE LEROMETER

-Y VELOCITY

ACCELEROMETER

-Z VELOCITY

Figure

8-29



Computer-Platform 8-119 CONFIDENTIAL

ACCUMULATOR

ELECTRONICS

Interface

CONFIDENTIALSEDR300

PROJEC--'-G

EM I N I

causes the output voltage of the stator winding to be phase-shifted the reference 400 cps voltage inputs to the computer: the compensalor winding

_e

a reference voltage from

(pitch, ya_, and roll references),

voltage from the stator winding

following PRO instruction

relative to

and a phase-shifted

(pitch, yaw, and roll gimbal angles).

programming

is associated with the Inertial Platform

interface : Signal

Address X

Y

Readpitchgimbal

6

3

Readrollgimbal

6

4

Readyawgimbal

6

5

The gimbal angles are read no sooner than 5 ms from each other, and the total reading time for all three angles is no greater than 30 ms. once per computation

in the catch-up, rendezvous,

every 50 ms in the ascent mode.

The angles are read

and re-entry modes, and once

These angles are gated, as true magnitude, into

the accumulator S, and I through 14 bit positions with the 15 through 25 bit positions being zero. discarded.

The accumulator value from the first PRO instruction is

Each of the next three PRO instructions

results in an accumulator

value of the glmbal angle read by the previous PRO instruction, as follows:

(a)

PROS6 (read pitch; process previously read angle)

(b)

Discard previously read angle

(c)

Wait 5 ms

(d)

PR046 (read roll; provess pitch)

(e)

STO pitch

8-12o CONIFIOENTIAL

CONIFIIDiENTIAL

SEDIt 300

(f)

waAt

(g)

PRO56 (read yaw;

(h)

STO roll

process

ii

roll)

(i) wait5 ms (J)

PRO36 (read pitch; process yaw)

yaw The computer inputs frcm the Inertial Platform are

s_...-_._ized as follows:

(a)

Roll gimbal angle

(b)

Yaw _mbal

(c)

Pitch gimbal angle (XPRLPPSRPC) andlreference (XPRIPCRPPC)

(XPR4PPSRRC) and

._ference (XPR_PCRPRC)

angle (XPR3PPSRYC) and reference ((XPR3PCRPYC)

The computer output to the Inertial Platform is _._rized

as follows:

Gimbal angle excitation (XCEGAE) and return (XCEGAEG)

System Electronics (Figure

8-30)

Outputs derived from each of the three platform accele_eters computer as incidental

are supplied to the

velocity pulses (+X and -X delta velocity, +Y and -Y delta

velocity, and +Z and -Z delta velocity).

An up level on one Line denotes a posi-

tive increment of velocity while an up level on the _ther line denotes a negative increment of velocity.

The following PRO instruction programming is associated with the System Electronics interface:

8-121 CONFIDENTIAL. iI

CONFIDENTIAL •_._

_

SEDR 300

PLATFORM ELECTRONICS

DIGITAL

COMPUTER

+ X VELOCITY

FROM PLATFORM

+ X DELTA VELOCITY CONVERSION CIRCUIT

-X DELTA VELOCITY I

-X VELOCITY

(XEDVPL) (XEDVML)

INERTIAL

+ Y VELOCITY

FROM PLATFORM

+ Y DELTA VELOCITY

(XEDVPY)

CONVERSION

INPUT

CIRCUIT

-Y DELTA VELOCITY

____

J

-Y VELOCITY

(XEDVMY)

PROCESSOR

INERTIAL

+ Z VELOCITY

FROM

+ Z DELTA VELOCITY CONVERSION CIRCUIT

-Z DELTA VELOCITY

(XEDVPZ)

,

(XEDVMZ)

ACCUMULATOR

Figure

8-30

Computer-Platform 8-122 CONFIDENTIAL

Electronics

Interface

CONFIDENTIAL.

SEDR 300

Signal

Address

Processor

X

Y

PHASETIME

Read X delta velocity

5

4

2

ReadY deltavelocity

5

4

3

ReadZ deltavelocity

5

_

The input processor accumulates the incremental velocity pulses on the processor delay line in two 's-complement form.

The velocity p_aes

have a mnximum frequency

of 3.6 kc per channel with a minimum separation of 135 usec between any plus and minus pulse for a given axis.

Three input circuits are used to buffer the plus

and minus pulses, one circuit for each axis. /-

The buffered velocity p_11ae inputs i

are sampled during successive processor phases and read into a control circuit. This control circuit synchronizes the inputs with the processor timing and establishes an add, subtract, or zero control for thelprocessor carry-borrow circuit.

The Bccumulated velocity quantities are read into the accumulator S, and

1 through 12 bit positions in two's-complement form via a single PRO45 instruction, as follows:

(a)

Processor phase 2 - read accumulated X velocity

(b)

Processor phase 3 - read accumulated Y velocity

(c)

Processor phase 4 - read accumulated Z velocity

As the accelerometer values are read into the accumulator, the delay llne is automaticslly zeroed so that each reading represents the cb,_e

in velocity from the

previous reading.

The cow,purer inputs from the System Electronics

are s_-_rized

8-123 CONIFIOI!NTIAL

as follows:

CONFIDENTIAL

PROJ':-'t--'6EM,NI SEDR300

(a)

+X delta

velocity

(]IED_L)

(_) -xde1_ velocity (X_) (c) +_del_ velocity (_) (d) -_del_ veloclty (_) (e)

+Z delta

velocity

(3_DVFZ)

(r) -zael_ veloclty (x_z)

The computer

supplies

a filtered

the dc power

supplied

to the cumpu_er.

computer

within

the cumpu%er

28 vdc si_l

The IGS Power

0.3 second after receivlng

power

control

dc power frum the computer

signal drops within

to the IGS Power Supply

the 28 vdc power

Supply

is not controlled

control

present

at the computer

Supply

and is therefore

control

to control power

signal.

Supply

by the computer whenever

inputs

from the IGS Power

(a) -_7.z vdc(m_7_)

Supply are m,_lzed

as follows:

a_ ret=n(_mT_m_)

(b) -_.2_c (xs_7_c)_d retu= (Xm_TVDC_) (c) -_ _c (Xm_O_) _

ret=.(_0_)

(d) +9.3_e (XSmV_)_

ret=n(X_VDm_)

(e)

The e_mpuT_r

26 vac (XS26VAC)and return (X_9.6VACI_)

ou%19ut to the IGS Power

Power e_rol

Supply is m_-vlzed

(XCEP)

CONFIDENTIAL

When

furnished power

the IGS Power

is operating.

The computer

to the

removes

The 26 vac, _OO cps power

to the eumputer by the IGS Power signal,

supplies

to 2 vdc, the IGS Power

0.3 secomd.

Supply

as follows:

CONFIDENTIAL

PROJECT

GEMINI

IGS POWER SUPPEY

DIGITAL

+ 27.2 VDC (XSP27VDC)

J

i

i

RETURN (XSP27VDCRT)

!=

-27.2VDC CXSM2_'DC_

COMPUTER

i Ii

RETURN (XSM27VDCRT)

I

+ 20 VDC (XSP20VDC)

l

!

RETURN (XSP2OVDCRT)

REGULATORS POWER

J |

+ 9.3 VDC (XSP9VDC)

i

J

RETURN (XS P9VDCRT)

i

J

I "

i 26 VAC (XS26VAC) RETURN (XS26VACRT)

_ I I i

i

400 CPS FILTER

I

i i ROWER CONTROL

(XCEP) i ! I

RETURN (XS P28VDCRT)

_

+ 28 VDC FILTERED (XSP28VDC) POWER SEQUENCING CIRCUITS

I

AUXILIARY COMPUTER POWERUNIT

1

Figure

POWERLOSSSENSING(XQBND) +28 VDC FILTERED (XSP28VDC)

8-31 Computer-Power 8-125 CONFIDENTIAL

Supply

:Interface

J

I

CONFIDENTIAL

PROJECT

Auxiliar_

com_uter

Power

The ACPU functions interruptions

in

and

pression,

it

cuits

in

until

the

The

computer

The computer

power

to

the

the

by inserting capability

the

sensing

into,

crew

with

new data to verify

into

sensing maintains

ends

to

a power

signal

s--_arized

ACPU is

to

the

buffer

computer

(up

to

power

interruption power

the

as

su_tzed

sequencing

power

a -_wlmum

or

decir-

constant of

lO0 msee).

follows:

as

follows:

(XQBHD)

(_IU) and/or

(Figure 8-32) read

a means of the

out

of,

updating

appropriate

the data stored

Two of the quantities Time Reference

ACPU senses

depression

ACPU is

Supply

filtered

can insert

provides

IGS Power

(_CEP)

from

loss

8-B1)

the

loss

or

Data Insertion Unit

The HDIU

with

The ACPU then

Control

+28

(Figure

When the

interruption

input

Power

It

the

output

Power

Manual

depressions.

computer.

power

(ACPU)

conjunction

supplies

the

Unit

GEMINI

the

cerl_sin

up to

dat_

which may be inserted

99 det_

stored

memory location.

in a number

System by the computer,

computer

Zt

of additional

in also

the

computer

provides

memory

(TR and _X) are transferred

following

words.

a

locations. to the

insertion.

The NDIU consistsof two units: The Manual Data Keyboard (MDK) and the Manual Data Readout used during presses

(KDR).

The MDK has a keyboard

data insertion

seven data-insert

of the computer

memory

and readout. push-button

location

containing

To insert

switches;

in which

I0 push-button

data,

the first

the pilot

8-126

always

de-

two set up the address

data is to be stored,

CONFIDENTIAL

switches

and the last

five

CONFIDENTIAL

s o,oo

PROJECT

MANUAL

DATA READOUT

DIGITAL

GEM

COMPUTER

!

READOUT (XNZRC)

CLEAR (XNZCC)

NI

ECDPOSAX) I

CCUMUL&.TOR SIGN NEG,

J_

_CDNEGAX)SIGN POS. _CCUMULATOR

_

ADDRESS XI

(XCSAXI)

DISCRETE iNPUT

! -

ADDRESS X2(XCSAX2)

LOGIC

ENTER (XNZJC)

ADDRESS SELECTION I

ADDRESS X3 (XCSAX3)



ADDRESS Y4(XCSAY4) ACCUMULATOR

ADDRESS Y5 (XCSAY5) ADDRESS Y3 (XCSAY3)

LOGIC

DATA READY (XMZDA)

l

-25 VDC (XCP25VDC)

,NSERT DATA 1_×N_B,, L

_OWER



INSERT SERIALIZER

_--_

DEVICE

B" -ZTURN (XCPM25VDCRT)

! I

_

INSERT DATA 4 (XMZB4)

=8 VDC (XCPBVDC)

C"

:ETURN (XC PBVDCRT)

i

E"

DiSPLaY DEVICES

INSERT DATA 8 (XMZB8)

MANUAL

NUMBER SELECT CIRCUIT

DATA KEYBOARD

INSERT DATA BUFFERS

RESET CIRCUIT

DATA READY CIRCUIT

INSERT ENCODER

Figure

8-32 Computer-MDIU 8-127 CONFIDENTIAL

r

-_VOC I×CMB_VDC, C,RCD,T ! A" SELECT

, IEGULATORS:, INSERT DATA 2 (XMXB2)

I

Interface

DISPLAY DEVICE DRIVE CONTROL

CONFIDENTIAL

PROJECT _.

GEMINI SEDR300

set

up the

FollorJJIK

the

_n

JJumr_io_

mrltoh

is

verification and the

(1eta.

8_tua_

Each

presse_

to

ve_lfi_ti_

the

8_

dat_

d_tts

store

_t

be set

the

the

and verifying

up e4_in.

READ 0_T push-button

catien.

switch.

The M_ This

switch,

two

The select_l

a two-digit the

seven

The following

a_ress,

sxlAress digits

prior

to

displayed

CLD instruction

programming

zero

is

_

meuo_

unit

mrltoh

is

be use_

is

then

and then display_

for

prusse_ for to

_epressing verifi-

than seven dAglts, or fails to

the

ERT_

or READ 0_T push-button

indicating

associated

a pilot

with

the

error.

_)IU

interfaces

_dress Y

Data _

1

0

Enter

2

0

Readout

3

0

Clee_

_

0

programming

is

associate_

with

the

MD1U interface.

Address

Signal

Digit magnitude weight i

8-128 CONFIDENTIAL

re-

attempts _o

X

PRO instruction

If

displ_s

oaa also

_tgtts

Si_

The following

l_sh-

lo_tto=.

in an invalid _ress,

depress___-_ all

the

sequentially

(adAress)

inserts _re

are

verification.

This operation is aee_lishe_

_ata

Tf the pilot at-temptsto insert d_a

read data out of an inv_ insert

first

for

push-button

by the pt1_.

ceLly the

digit,

seleot_1

_

check quantities s_ore_ in the computer memorT. _y inserting

displa_ed

seventh

dAt_ in the

be _--_,

4-ger_e_

also

of the

the

onnnot

is

inserts&

8na verification

of 8_y digit

8_&ress

dAgit

X

Y

0

3

.....

CONFIDENTIAL

P........

x

!

Dl_t magnitude vetgbt 2

i

3

Digit

me_.t"_(le vetgbt _

2

3

Digit

_.tude

3

3

weight

Reset DIOI, Display

off.

is

device

0

drive

1 i

0

5

Digit

select weight

2

1

5

Digit

select

h

2

5

Read MDIU insert data

3

_J.ght

_epress

the CIRAR push-button

or displayed.

Thls

results then

& &igit

entereA

Upon

4-to

DI01_

ana DI03,i and elearlng I the display drivers.

switch Is _epressed,

the bv_Cer

ema DIOI is

blt positions

The progr_

quantity

DI02,

sets DO_I off to reset

then

t_trned

1 through

sends out a code by means

be _Isp]_ye_.

switch for the first

the reeo_wn_tlon of DI0_ ion, the progran Ii

in resetting

push-button

into a_omallator

program

DI02, ana DI03

select weight

The pro_Im

When

8

Digit

The pilot must Inserted

I

on.

D051,

oode_

The program

_ an_ sets _0

of D050,

sets _0_l

the ht_7

ofT.

to be

sets DO_O

the MDIU buffer.

e(xle

aec_ml

(B_D)

re_ls

the hurter

Fo]_oeln_

and iD052 to select

on to turn ion the 41spla_ i

this,

the 4/glt _rIvers,

the

to a_1

senAs a BCD dl_It to the buffer by means of D030, D0_, D032, and D033. The pro_m

walts

the atgit

0.5

seoo_d

is atspl_ea

and sets

D0_O and D0_l

before enterin_

have been entereA and at_,

The pilot

the next dtgt%. /

the pilot

This remLlts in _IO_ beta_ set on.

off.

The _

After

must

all

nit

until

seven atgtts

aepresses ithe _ l_sh-button mrlteh. i then Isets D0_0 ofT, sad eon_s

8o129 CONFIDENTIAl.

CONFIDENTIAL

PROJECT

GEMINI

SEDR 300

the

flve

eordlu8

_

d£81ts

to the

to binary.

This

data

is

sealed

the 1M.lot enters

queatit¥

depresses

to be dtspla3_

results

in DI03 being

quested

quantlty

a_l set

the

The ccml_t_r

on.

the

then

BeD data

the _vo-_:I.l_Lt a(1.___-ess of the

READ OUT lmsh-but_on sets to

D0_O off_

the

svttch.

converts

dtsp]_y

buffer

This

the

re-

one digit

at

intervals.

_prts

fr_

Readout

the _1_

are sumanlzed as follovs_

(I(ZRC) - The up level

prevt_s]_

(h)

then

to BeD, and sends

a fine in 0.5-sec_l

(a)

in memory ae-

two-d£E_Lt exldress.

'1'o read (h_ta out of the ecmputer_

The eo_u_

an_ stored

inserted

dL_tts

are

_i_

to be _tepl_e_.

Clear

(]NZCC) - The _p level

Wlously

4-serte_

dt_ts

of this to

signal

be used

of this

are

incorreot

(XWZZC) - The up level

of this

si_

denotes

as the

ad_ess

denotes

and the

that

rye

of a

that

insert

the

the

pre-

sequence

must

be repeated.

(c)

Enter l_masl_ the

(_)

tnser_e_

rea_

d_git

b_

20 times

(e)

Znsert four

have

been

denotes

verified

that

and should

the

pre-

be stor_l

in

memoz.y.

e_ter

D_te

digits

si_

(_W_.r_) been per

data si_3.s,

- The up level

inserted.

secon_

to

of this

The computer al_o_

continuous

signal

samples insertion

1, 2_ }_ an¢_ 8 (_'A_B1, X/wz.w, ]1,_ d.enott__ one _CD chaz.a_er,

8-_3o CONFIDENTIAL

denotes this

that

line

at

a least

of data.

and. ]3_8)

are mrj_lte_

- These

to the cam-

CONFIDENTIAL

__

SEDIt300

i

puter for each decimal digit inserted.

The computer outputs to the _IU

(a)

_ccumulator sign positive (XCDPOSAX) - The up level of this signal on a set

(b)

ir_ut

causes

the

addressed

la_ch

to be set.

Accumulator sign negative (XCDNEG_X) -!The up level of this signal on a reset

(c)

are sur_narized as foli_s:

input

causes

the

addressed

ilatch

to be reset.

Addressing - Seven lines provide the Q_pability of addressi_ lslches in the _IU.

all

The following X iand Y address lines are pro-

vided:

(i)

MDIU address XO (XCSAXO)

(2)

_IU

(3)

MDIU address X2 (XCSAX2)

(4)

MDIU address XB (XCSAX3)

(5)

MDIU address Y3 (XCSAY3)

(6)

_IU

address Y4 (XCSAY4)

(7)

_IU

address Y5 (XCSAYS)

address Xl (XCSAX1)

By selecting one X and one Y address line at a time, a total of 12 addressescan be formed.

(d)

Power - Regulated dc power is supplied to the MDIU as follows: (i) (2)

+25 vdc (XCP 25VDC) and return (XCPM25VDCRT) i -25 vdc (XC_5VDC) and return (XCPR225qfDCRT)

(3)

+8 vdc (xcPSVDC) and r@turn (XCP8VDCRT)

8-131 CONFIDENTIAL

CONFIDENTIALSEDR 300

The TRS counts Elapsed Time (ET) from ].ift-offthrough impact, counts down time to

retrograde

(TR) on c¢_mand,

and counts

cnmmand, all in I/8-second increments.

down time

to

equipment

The computer receives TR

words from the MDIU end automatically transfers them to the TRS.

reset

(Tx)

on

and TX data When the com-

puter receives a display request from the MDIU for TR, or when the computer program requires ET_ the TRS transfers them to the computer.

The following CLD instruction progr_mming is associated with the TRS interface.

Signal

Address

TR discrete

X

Y

5

0

The following PRO instruction programming is associated with the TRS interface:

Signal

Address X

Y

ET control

4

1

TX control

5

2

TR control

5

6

Enter

1

2

TRS data 8nd

0

2

4

1

timing pulses TRS control reset

In the readout mode, the computer transfers TR or TX data words to the TRS. mode is initiated by setting DO21 on.

The

The 24 bits of data to be sent to the TRS

8-132 CONFIDENTIAL

CONFIDENTIAL

PROJECT

GEMI

I I

DIGITAL

COMPUTER

TIME REFERENCE SYSTEM

TR EXCITATION +8V

INPUT DISCRETE

LOGIC DATA INPUT

i

LOGIC

(XCDGTRE)

C

"_

C

I

AI

TR DISCRETE (XGT£)

I

I

TRS DATA INPUT (XGDAT)

_

,-_"

TR=0

TRS DATA OUTPUT (XCDXRCD) ENTER (XCD[NT)

1

!

=

O

.... I A

I _

-

I

I

I

.

I Ai _-

:

: A

TRS TIMING

PULSES (XCDTRT)

TRCONTROL XCDT G

DISCRETE OUTPUT

Tx CONTROL

(XCDTXG)

.I TT,0G,MSEITE I i l

Figure

8-33

Computer-TRS 8-133 CONFIDENTIAL

Interface,

Tx TIME REGISTER

C

=

CONFIDENTIAL

PROJECT-'GEMINI $EDR 300

are

then

(shift is

¢- the

placed right

one place)

aut_atlca_y

timing been

pulse sent

e_cumu_tor

is

to

the

by 2_ consecutive

instructions.

With each

_-_tiate_

70 usee

after

terminated

so that

its

TRS_ the

progr_

the

of PRO20 and S'HR1

PRO instruction,

beginn_n 5 of the

up level

generates

sets

is

139 usec.

one of two control

a tt-_ug

pulse

data

pulse.

The

Ai_r

bit

gates

2_ has

(_

or TX).

Between 9 and 15 ms later, the computer terminates the TRS control gate.

The enter mode is initiated by setting D021 off.

One of two control gates (E_ or

TR) is generated by the pro£_ramen_ terminated between 9 an_ 15 ms later.

After

termination of the control gate, the program enters a subroutine consisting of consecutive sets of PROIO an_ _

instructions.

Every time a PRO operation is

called for, a timing pulse is generated by the same logic as in the readout mode. The t_4"5

pulse

the coaster.

is

sent

to the

TRS to

cause

the

addressed

data

to be supplied

The flrst bit reeeived is aiscarded wlth the final _

to

instruction.

The seeon_ bit received is the least significant bit and is shifted into ace_at the e_letion

lator bit position _ instructions. line

to

the

of the tvont¥-fifth set of PRO20 an_

When TR equals zero, a relay in the TRS connects the _

TR discrete

14,e.

The TR discrete

signal

then

causes

the

excitation ecmz_ater

to

start re-entry calculatlons.

The computer

(a)

inputs

from the

TR di_rete

TRS are

(_JSt)

smmm_ized

as follovs:

- The up level of this signal signifies that the

e

eo_puter shou_

begin re-entry calculations.

o

the

ee_puter occur on this line. mined by _hieh eontrol _te

CON

tothe

The _ata word on the llne is deterthe eaaputer actuates prior to the

FID_NTIAL

CONFIDENTIAL

_@

SEDR300

actual

The computer

outputs

(a)

data transfer.

The up level

to the TRS are sum-rized

TR excitation resistor

is a binary

I.

as foll_)ws:

(SCDG_I_E) - The computer

supplies

+8 vde through

to the _RS as the _R excitati6ni input.

When

a

TR equals

i

zero, the _R relay to the computer

(b)

Enter

(XCI_)

causes

the TR excitation

as the _R discrete

- The up level

input

to be transferred

signal.

of this _ignal

signifies

that

data

i

is to be transferred

from the TRS to the computer when the transfer i The down level signifie_ that data is to be trans-

clocks occur. feted

(c)

from

TRS data

the

computer

output

(XCDXRCD)

to the TRS occur mimed by which

to

control

TRS timing computer

pulses

gate

(e)

TR control

(TR

The da_a word or _)

from the computer on the line

the computer

is deter-

has actuated.

i.

(XCSYI_)

data to be shifted

for transfer

_IS.

- All data transfers

on this lime.

The up level is a binary

(d)

the

- These

3.57 kc timing

pulses

cause the

into or ou_ of the _RS buffer

register

to or from the computer.

(XC_)

- The up level of _his

fer of data between

the TRS buffer

ter.

of transfer

The direction

signal

re_ister i

is determined

causes

and the _

the transTR regis-

by the level

of the

|!

entersignal.

(f)

TX control

(XCI_)

- The up level

8o135 CON FIDINTIAL

of ithis signal

causes

the trans-

CONFIDENTIAL SEDR 300

fer of data between the _RS buffer register and the TRS TX register.

The direction of transfer Is determined by the level of the

enter signal.

(g)

ET control (_)

- The up level of this signal causes the trans-

fer of data between the TRS buffer register and the TRS ET register.

The direction of transfer is determined by the level of the

enter signal.

Diglt, cond s st,@cs)(Figure The DCS accepts BCD messages from the ground stations at a I ke rate, decodes the messages, and routes the data to either the TRS or the computer.

In addition,

the DCS can generate up to 6_ discrete commands.

Sign% l

Address

DCS ready

X

Y

6

0

The following PRO instruction programming is associated with the DCS interface:

Signal

Address X

Y

Computer ready

I

0

DCS shift pulse gate

0

0

When data is to be sent to the computer, the DCS supplies the computer with a DCS ready discrete input (DI06).

This input is sampled every 50 ms or less in all com-

puter modes except during the I/8-second interval in the ascent mode when reading ET at lift-off.

To receive DCS data, the computer supplies a series of 2_ DCS

8-136 CONFIDENTIAL

CONFIDENTIAL

__

PROJECT

GEMINI

i=

D'G'TALCO ICONT CSRETU O iD'G C, i

1

J

ACCUMULATOR

J

t RETURN (XDDATG)

INPUT LOGIC

DATA BUFFER

RETURN (XCDCSPG)

Figure

8-34

Computer-DCS 8-137

CONFIDENTIAL

:

Interface

DISCRETE OUTPUT LOGIC

CONFIDENTIAL

PROJEMINI __

SEDR300

shift pulses at a 500 kc repitition rate by setting D001 off and programming a PRO0 instruction. register

to

positions dress Bit

These shift pulses cause the data contained in the DCS buffer

be shifted

1 through

of the

out 2_,

associated

position

19 (address

with

on the

DCS data

position

quantity portion)

line

and read

19 through

and position and bit

2_ containing

1 through

position

into

accumulator the

18 containing

1 (data

portion)

bit

assigned the are

adquantity.

the

most

significant bits.

The computer inputs fro_ the DCS are s,_rized

(a)

as follows:

DCS ready (XDRD) and return (XDRDG) - The down level of this signal signifies that the DCS is ready tO transfer data to the computer.

(b)

DCS data (XDDAT) and return (XDDATG) - This serial data from the DCS consists of 2_ bits, with 6 being address bits and 18 being data bits.

The computer output to the DCS is su_,_rized as follows:

DCS shift pulses (XCDCSP) and return (XCDCSI_) - The computer supplies these 2_ shift pulses to the DCS to transfer data contained in the DCS buffer register out on the DCS data llne.

Rendezvous Radar (Figure 8-35) The Rendezvous Radar supplies the computer with three data inputs: range to target, sine of azimuth, and sine of elevation.

line-of_sight

In the rendezvous mode,

the computer uses radar data to compute and display velocity to be _ined body coordinates).

8 -138 CONI=UDENTIAL

(in

_

CONFIDENTIAL SEDR300

_- __ _

ENDEZVOUSRAOARI I I LD'G'TALCOM CONTROL

-

CIRCUITS

l

RETURN (XREDG)

DISCRETE INPUT LOGIC

RADAR READY (XRED)

REGISTER

AZIMUTH REGISTER

ACCUMULATOR

SINE

ELEVATION REGISTER _

SINE

t RAOAR SERIAL DATA C×RDAT_

OUTPUT REGISTER

ij

LOGIC

DATA

RADAR SHIFT PULSES (XCDRSP) RETURN (XRDATG) RETURN (×CDRSPG)

INPUT

DISCRETE OUTPUT

I coNTroL I: CO PUTERREAO LOO,C CIRCUITS

RETURN (XCDCRDG)

Figure

8-35

Computer-Radar 8-139

CONFIDENTIAL

Interface

CONFIDENTIAL

PROJ

E'-E-C-T--GEM

IN I

SEDR300

The following

CLD instruction

progr_mlng

is associated

with the Rendezvous

Radar

with the Rendezvous

Radar

interface:

Addre,s,s

Radar

The following

ready

PRO instruction

x_

x_

0

0

prosr-_mir_

is associated

interface:

sisal

x_

X

I

0

Reset radar ready

3

6

DCS shift pulse gate

0

0

C_puter

When the e_puter is supplied radar signal

_,_,e,ss

ready

requires

radar data, the computer

to the Rendezvous

ready discrete

Radar.

input buffer

completion

sets of PR000

register

500 kc pulses

output

The computer

data and to enter The program

sequence:

8-1ho CONFIDENTIAL

ready

a hold

waits

If the test is negative,

are given.

(IDOl)

has reset the

20 ms three

Each PRO instruction

to be sent to the radar to shift

of the radar data output register.

in the following

instruction.

cycle.

(DI00).

and STO instructions

a burst of fifth-two

the contents

input

discrete

the progr_n

its internal

of a data acquisition

and tests the radar ready discrete consecutive

to this,

with the PR063

causes the radar to stop updating

mode following

causes

Prior

ready

The data appears

out

in the output

CONFIDENTIAL

PROJE ___

SEDR 30_

(a)

Range - 15 bits

(b)

Sine azimuth - iO bits

(c)

Sine elevation - i0 bits

i

i

A del_y of 280 usec occurs before the leading pulse of each 500 kc burst to enable the computer to store the data it has received and to allow the next data word to be inserted into the radar data output register in preparation for transmission to the computer.

Radar range data is read in true

magnitude form into accumulator bit positions 8 i

through 24.

If bit positions 8 through Ii (four mostIsignificant bits) are l's, I

the radar r-_e

data is considered unreliable and is _nored.

Sine azimuth and

sine elevation data are read into accumulator bit positions 15 through 24. iI

The computer inputs from the Rendezvous Radar are s,m_arized as follows: I

(a)

Radar ready (X_)

and return (XREDG) -iThe up level of this signal I

signifies that the radar has recognizedlthe computer ready signal and is ready to transfer data.

The radar ready pulse occurs between i

0 and 4000 usec after the c_uter has

(b)

rea_

pulse, if radar lock-on

occurred.

Radar serial data (XRDAT) and return (_) - This data consists i of three words which occur in a fixed format as determined by the

iI

radar shift pulses.

The first word is _ange to target (15 bits), I I

the second word is sine of azimuth angle (i0 bits), and the third _ord

is sine of elevation angle

8-l_l CONFIDINTIAL

(I0 bit_).

CONFIDENTIAL

PROJECT __

GEMINI

SEDR300

The computer

outputs

to the Rendezvous

Radar

(a) Radarshiftpulses(X_)

groups

the radar

of 52 pulses

are _.._rized

as follows!

and return(XC_S_) - These500 kc

pulses are issued between puter receives

______j

280 usec and _ millisec read_

signal.

each I with

after

the com-

They are sent out as three

a 280 usec delay

_efore

the leading

edge of each group.

(b) Computerready(XCDCRD)and return(XCDCRDG)- The up levelof this signal

$$ti_ude During

_Isplay/Attit_xde

the ascent mode_

signals

and supplies

Attitude

During

Display

that the computer

add Maneuver

the computer

and rendezvous

modes,

and is capable

(A_)

roll,

(Figure

the computer

inputs.

8-36)

and yaw attitude

The pilot utilizes

of the ascent

of supplying

radar data

guidance

generates

error

the

equil_nent.

pitch

th_n to the Attitude

and yaw Display

AC_.

the re-entry

signal and supplies

mode,

the computer

it to the Attitude

with

zero lift is equal to the computed

hank

rate

comnsnd

roll attitude equal

pitch,

Display.

the performance

requires

Electronics

generates

th_n to the Attitude

attita_de error signals

During

_ontrol

to monitor

the catch-up

and. the

signifies

equivalent

error output

signal is supplie_

the oomputer

generates

Display range

to a IS _egree

line.

to that for the deslre_

attitude

generates

a roll attitude

and the ACME. to the desired

per second

point,

on the output

cross range end down range

8-Z_,2 CONFIDENTIAL

Also, error

duri_

rate

If range to touchdown touchdown

with

the appropriate

line.

or bank

point,

roll rate is provided

If the range to touchdown

touch_own

error

a on the

zero lift is not

roll rate or ro_1 the re-entry

signals

mode,

and supplies

CONFIDENTIAL SEDR300

f_"



them to the Attitude

Display

re-entry

of the spacecraft.

flight

The following

path

i

for the pilots'

PRO instruction

progrs_ng

use in _nu,S1y

is associated

controlling

the

with the Attitude

Display

and ACME interfaces:

Signal

Address

x

X

7

0

Yaw error command

7

i

Roll error

7

2

Pitchresolution

2

0

Yaw resolution

B

0

Roll resolution

4

0

Pitch

error cc_nand

ccmnand

f_

The pitch, accumulator address

yaw,

is sampling

previously time

sampled

is 48 ms.

adc

is then

commands

are written

S, and 8 through

The outputs

generate

analog voltage circuit

error

bit positions

of 7.

works which

and roll

of the register voltage

sampled

equivalent

output,

The minimum

The Y address

a seven-bit

to ladder

to the buffered

is 2 ms,

mentioned

the one sample

and hold

circuit

that

digital

error.

of each sample

and hold

circuit

is fed into an individual

and the maximum

PRO instruction

is to ssmple the ladder

8-14B

decoding

an X netThis

and hold circuits; while one i two circuits are holding their

ssmple time

CONFIDENTIAL

having

from

ssmple

the other

of the previously

register

_ PRO instruction

are connected

by one of three

the ladder value.

13_ with

i_to

output.

ladder

hold

selects

The output

amplifier

where

CONFIDENTIAL

PROJECGEMINI .___

SEDR300

the DC analog voltage for each channel is made available for interfacing with the Titan Autopilot.

The dc analog outputs are also fed through individual range switches and magnetic modulators

where the dc voltages are converted to 400-cycle analog voltages.

The

range switches, which are controlled by means of discrete outputs, can attenuate the dc voltages being fed into the magnetic modulators by a factor of 6-to-l. addressing

of the discrete

The

outputs for controlling the range switches is as fol-

lows:

(a) (b)

Pitch or down range error (DO02) - _ Yaw or cross range error (DO03) -

(c)

Roll error (DO0_) -

plus for low range; minus for high range.

The error commands are written every 50 ms or less.

_

is dependent upon the computer mode of operation.

The updating period, however, For the catch-up, rendezvous,

and re-entry modes (and the orbital insertion phase of ascent guidance), the error co_ands

are updated once per computation cycle or every 0.5 second or less.

For first and second stage ascent guidance, the error co_nds

are updated every

50 ms or less.

The computer outputs to the Attitude Display and ACHE are s_:mmarizedas follows:

(a)

Pitch attitude error (SCLPDRM) and return (XCIPDRMG) Two identical sets of outputs (A and B) are time-shared between pitch attitude error (during ascent, catch-up and rendezvous)

8-i_4 CONFIDENTIAL

CONFIDENTIAL

__

SEDR30O

and down range

error

(during Re-entry).

(i)

Pitch

attitude

error

(ascent) !

(2)

Pitch

attitude

error

(cat'h-up

Attitude (3)

(b)

Roll

!

(XCIROLMG)

Display

Down range

attitude

error

error/bank

rate

- Two identical

shared between

!

to Attitude

Display

and rendezvous)

to

i (re-entry)

to Attitude

I(XC_OLM) command i

Display

and return

sets of ou/;puts (A and B) are time-

roll attitude

error

an_ bank rate

command.

Dur-

i

ing ascent, entry,

it represents

hc:_ever,

it

only roll attitude i I

represents

roll

attitude

error. error

During

re-

when the

I

_--

computed

range

is less than the desired i

range,

and a 20 degree

I

per second bank rate exceeds

the

desired

command when range.

the computed !

range

equals

or

i l

(i)

Roll

attitude

error

(ascent)

to Attitude

Display

(2)

Roll attitude

error

(re-e:itry) to Attitude

Display

and ACME (3)

Bank

rate comand and

(c)

Yaw attitude

error

(re-ent ._j)to Attitude

Display

ACI_

(XCLYCRM)

and retum

(XCLYCRMG)

- Two identical

!

sets of outputs

(A and B) are time-shlred

between

yaw attitude

i

error

(during ascent,

catch-up,

I and rendezvous)

error (during re-entry). f

8-i_5 CONFIDENTIAL I

and cross

range

CONFIDENTIAL

PROJ E--E'CT-'M

IN I

SEDR300

(I)

Yaw attitude error (ascent) to Attitude Display

(2)

Yaw attitude error (catch-up and rendezvous) to Attitude Display

(3)

Cross range error (re-entry) to Attitude Display

During ascent, the computer performs guidance computations in parallel with the Titan guidance and control system.

If a malfunction occurs in the Titan system,

the pilot can switch control to the Inertial Guidance System.

For a description

of the program requirements and operation associated with the Tital Autopllot interface, refer to the Attitude Display and ACME interface description.

The computer outputs to the Tital Autopilot are summarized as follows:

(a)

Pitch error (X_)

(c)

Yaw error (XCLYDC) -

(d) (b)

Comzon return (XC_) Roll error (XCIA_DC)-

(e)

Autopilot scale factor (XCI_SF) pilot dyn_cs

-,-

-

backup ascent guidance. __

These signals are provided during - This signal cha_es

the auto-

after the point of maximum dynamic pressure is

reached. (f)

Second ste_e engine cutoff (XCDSSCF) - This signal is generated when velocity

to

be gained

equals

8 OONFIDINTIAL

zero.

CONFIDENTIAL

_---_

PROJECT

DIGITAL

GEMINI

i

ATTITUDE CONTROL AND MANEUVER ELECTRONICS

COMPUTER

ACCUMULATOR

J

1 RETURN (XCLROLMG

-A)

CIRCUITS

LADDER LOGIC

I

Ji . jI ATT,TU_ D,SPLA¥

ROLL ATTITUDE ERROR (XCLROLM-B)

I

I

RETURN (XC LROLMG -B)

i

YAW ATTITUDE ERROR (XCLYCRM-B)

i

PITCH ATTITUDE ERROR (XCLPDRM-B)

i

RETURN (XCLPDEMG -B)

p_.

_ :

'Jl

DISPLAY

i

=

RETORN_XCL_CRMG_ Jl =I i

i Figure 8-36 Computer-Attitude

DIGITAL

Display/ACME

Interface

COMPUTER

TITAN AUTOPILOT

ROLL ERROR (XCLRDC) LADDER

I YAW ERROR (XCLYDC)

!

RETURN (XC LDCG)

L

I

LOGIC I

DISCRETE OUTPUT

J

SEC. AUTOPILOT STAGE ENGINE SCALE FACTOR CUTOFF(XCDAPSF) (XCDSSCE)

Figure

8-37

Computer-Autopilot 8-147 CONFIDENTIAL

i

Inte rface

CONTROL CIRCUITS

CONFIDENTIAL

PROJ--3-EC-f--G

E M IN I

Auxiliary Tape Memory ,(A_) (Figure 8-38) The A_4 is interfaced with the Digital Computer and the following controls and indicators on the Pilots' Control and Display Panel (PCDP):

A_

mode switch

A_

0N/R_SET switch

ATM ERROR indicator A_I_RUN indicator

The crew, via the PCDP and the computer, controls the modes of A_ The Incremental Velocity Indicator (M)

operation.

are used to provide information on A_

ani the ATM ERROR and RUN indicators status.

The crew also uses the Manual

Data Insertion Unit (MDIU) for co..._uicationwith the computer and subsequent computer co-_.-__uication with the A_.

The following CID instruction progra_-_n_ is associated with the A_

Signal

Address

x_

Y_

ATM clock

i

A_4on

3

3

A_M d_ta channel 2

3

4

A_

4

i

4

3

mode control number i

A_4 beginning

or end of tape

A_

data channel 3

It

I_

A_

mode control number 2

5

i

A_

data channel i

5

3

8-148 CONFIDIENTIAL

interface:

....

/

CONFIDENTIAL SEDR 300

_

AIM

COMPUTER

REPRODUCE

--ATM

DATA 3 (XLDAT 3)

ELECTRONICS

--ATM

DATA 2 (XLDAT

--ATM --ATM

DATA 1 (XLDAT 1) CLOCK (XLOCK)

f

2)

DISCRETE INPUT CIRCUITRY

END OF TAPE (XLEOT) i

ATM ON (XLON)

:

POWER SUPPLY

_

AUTO VERIFY/REPRO

AND CONTROL CIRCUITRY

=

AUTO WIND

-

-

(XCDVR)

ATM MODE

I (XHMSAI)

ATM MODE

2 (XHMSA2)

•AUTO VERIFY/REPRO (XCDVR)-

(XCDWD)

(XCDWD) --

AUTOREWIND (XCDRW) AUfO

(XCDRW)--

WRITE (XCDWT)

(XCDWT)--

AGE WRITE ENABLE (XHDWEN) MANUAL --MANUAL

VERIFY/REPRO ( REWIND (XHDRD)

• -

-

MANUAL WIND i

-

-

ATM MODE SWITCHEXCITATION (XLSVDC)

DISCRETE OUTPUT CIRCUITRY

i WRITE ELECTRONICS

COMP.

SHIFT (XCDSH)

COMP.

CLOCK

COMP.

DATA (XCDAT)

(XCDCLK)

J

PCDP

SWITCH

ATMMODE I ATM ERRO_ LIGHT

TO CONTROL CIRCUITRY

_

_ ATMATM ON/RESEToFF 11

ON/RESET SWITCH ATM

(XLERR) ! :

l _ATM

INDICATION ERROR INDICATION AIMRUNNING (XLRN)

i 28V MAIN BUS

CIRCUITRY -

LIGHT

f

Figure

8-38

FROM CONTROL

Computer-ATM-PCDP

Interface

(S/C

8-149 CONFIDENTIAL i

8 thru

12 Only)

CONI=mDENTIAL

PROJECT ..

GEMINI SEDR30O

_"-_

The following PRO instruction programming is associated with the ATM interface:

A_4 wind/rewind reset

_

i

ATM verify/reprogram cc_and

_

4

ATM wind c_J,.,and

5

1

ATM rewind command

5

2

The computer inputs from the ATM are m_mrized

(a)

as follows:

ATM clock (XLOCK) - A two millisecond pulse for each three-bit parallel data output frame, delayed 1520 microseconds from the nominal beginning of each frame. down level less than one volt.

Up level six to twelve volts;

Rise and fall times less than 20

microseconds each.

(b)

A_4 data 1 (XI_tT 1), data 2 (x_.n&T2), data 3 (_.n&T 3) Parallel NRZ data output on three lines at a rate of 200 bits per second on each line. + 2_ of normal.

(c)

Individual bit periods are written

Other specifications same as for data outputs.

End-of-tape (XLEOT) - A logic level from the A_d to the computer. An up level indicates that either end of the tape has been reached.

(d)

A_4 on (XLON) - A logic signal from the ATM to the computer.

An

up level indicates that the A_4 has reached proper operating speed in the read and write modes.

8-15o

This signal appears approximately

(;ON lelO_NTIAL

CONFIDENTIAL

SEDR 300

five seconds write.

after

a command

It is inhibited

when

is given!

to the AS

to read or

either lend of the tape

is reached.

!

The computer

outputs

(a)

Auto

to the AS

are summarized

verify/reprogram

through ATM.

(XCDVR)

the AUTO position

An 8 vdc signal

the record

or write

as follows:

- A c_and

of the AT

on this

line from the computer,

i

TAPE mode

llne _auses

mode in the forward I

switch,

the AS

direction

to the

to operate

in

at a nominal

i

tape

speed of i. 5 ips. i

(b)

Auto wind AUTO

(X_)

position

signal

- An 8 vdc signal 1from the computer of the AUX TAPE mode

causes

the tape to move

witch,

through

to the AS.

in the forward

the

This

direction

at a

i

nominal

tape

speed of 12 ips.

the read mode

(c)

Auto

rewind

during

(XCDRW)

the AUTO position signal

(d)

Auto

write

position used

tape

- An 8 vdc signal

of the AUX TAPE m_e !

speed

of 12 ips.

(XCDWT)

- A signal

of the AUXTAPEmode

Computer

data

internally

(XCDAT)

from the computer, switch,

in the reverse

in

switch,

through

to the AS. direction

from the computer,

by the A_M to set up internal

data can be recorded

(e)

functions

this operation_

causes the tape to move

nominal

The AS

to the A_.

This

at a

through

the AUTO

The signal

_ontrols such that

is

computer

on the tape.

- Groups

of fQur serial

NRZ data bits,

each

i group or frame totaling 1120 microsecondsduration at a rate of i

8-151 CONFIDENTIAL

OONFUDENTIAL

PRMINI SEDR 300

200

frames

level

per

Up level

less than one volt.

fall time

(f)

second.

Com_uter having

shift (XCDSH)

a period

microseconds;

frame.

(a)

(b)

14 volts;

down

pulses.

begin

Rise

- Serial pulses

than

seven

time less than

having

a duration

per second

15

of 18

or one per

280 or 560 microseconds

four in each frame.

Up level

after

is seven

the to

Rise time less than ten

fall time less than O. 5 microseconds.

- Computer

switch excitation

interfaces (XL8VDC)

are summarized - A nominal

from the ATM to the AUX TAPE mode

AGE write enable

(]C_]_N)

position

it to send a write

Manual

verify/reprogram switch

(XHDVR)

to the A_

at a nominal

command

tape speed

8-152 CONFmDENTIAL

8 vdc excitation

from the ATM, through

switch,

to the AGE to

to the ATM.

- An 8 vdc discrete

which

as follows :

switch on the PCDP.

- An 8 vdc discrete

of the AUX TAPE mode

enable

write mode

70 microseconds

Up level greater

level less than one volt.

- PCDP and PCDP

TAPE mode

each pulse

and spaced 141 microseconds

input pulses

are delayed

of bit number

the STANDBY

(c)

(XCDCLK)

beginning

voltage

down

fall time less than 0.4 microseconds.

These pulses

ATM mode

volts;

of four serial pulses,

each at a rate of 200 pulses

microseconds;

A_

Shift

of the da_

clock

microseconds

Additional

- Groups

down level less than one volt.

Computer

seven

time less than 15 microseconds;

of 139 microseconds

after the s_rt

(g)

than

less than ten microseconds.

from the next pulse.

volts;

Rise

greater

causes the A_ of 1.5 ips.

from the AUX

to operate

in the

CONFIDENTIAL

(d)

Manuel

wind

(X_WD)

- An 8 vac

discrete

from

the

AUX TAPE mode

l

switch

to

the

direction

(e)

Manual

ATM which

causes

at a nominal

rewind

tape

(XHDRD)

the

_e

to

move

in

a forward

speed of 112 ips.

- An 8 vdc diserete

from

the AUX TAPE mode

l

switch

to the ATM which

causes

the tape to move

in the reverse

;

direction

(f)

A_

on/reset

ON/RESET A_

switch

(a_ly

A_ When

(j)

This

power)

the ADX TAPE ERROR

sil hal will

or re-i_tiate

28 vdc signal

It causes

error indication

(XLERR)

ever the error

detection

between

- A signal logic

parity i

tape

speed.

causes

PCI_

to illuminate.

transmitted

(XI_)

to the PCDP

extin-

from the ATM to the PCDP

circuits

from the data

running indication

while

from the AUX TAPE OFF-ON/RESET i

bits that are generated

A_

operation

initiate

the AT_ to cease operation.

the recorded

The signal

either

indicato r on the PCDP.

to the A_.

a disagreement

of if2 ips.

28 vdc si_hal from the AUX TAPE OFF-

to the A_.

ATM OFF - A momentary switch

(h)

tape speed

- A momentary

operation

guishing

(g)

at a nominal

the AS

in the A_I_ indicate

bits and the parity

during playback ERROR

indicator

at either on the

- A signal from the ATM which is

five seconds

after

the A_

is comm_nded

i

to operate indicator signal

in any mode. on

the

P_DP

is terminated

This

whenever when

signal iilluminates the A_ RUN i the tape is in motion. The

either

8-153 CONFIDISNTIAL

end of the tape is reached.

CONFIDENTIAL

PROJECT" __

GEMINI

SEDR300

(k)

Two mode controls (XHMSAI and XHMSA2) - Mode control signals supplied to the computer from the AUX TAPE mode switch on the PCDP.

The signals define the A_

mode selection.

MODE POSITION

XHMSAI

XH_A2

AUTO

i

i

REPRO

0

i

All Others

0

0

pilots' Control and Display Panel (PCS)P),(Figure8-39 ) The following CLD instruction programming is associated with the PCDP interface:

Signal

Address X

Y

Computer modei

i

I

Computer mode2

0

i

Computer mode 3

3

I

Startcomputation

i

2

Abort transfer

7

1

Fade-in discrete

6

1

8-19_ CONFIDENTIAL

CONFIDENTIAL

I

!_-_

PROJECT

PI LOTS' CONTROL DISPLAY PANEL

GEMINI

AND

DIGITAL

COMPUTER

POWER

COMPUTER

COMPUTER ON (XHONP)

ON-OFF SWITCH

COMPUTER OFF (XHOFF)

I

CIRCUITS I

SEQUENCING

COMPUTER MODE

COMPUTER MODE

2 (XHMS2)

SWITCH

COMPUTER MODE

3 (XHMS3)

!

i START COMPUTATION SWITCH

COMPUTER MALF. RESET SWITCH

/_--"

I J

START COMPUTATION

(XHSTC)

j DISCRETE iNPUT LOGIC

MALFUNCTION

RESET (XHRST)

I

RELAYS

FADE_IN

DISCRETE (XHSFI)

RUNNING LAMP J

COMPUTER

COMPUEER RUNNING

I

TO COMPUTER CONTROL SWITCHER _

(XCDCOMP)

DISCRETE OUTPUT LOGIC

SWITCHEXCITATION (XCDHSME) _ +8VDC

Figure

8-39

Computer-PCDP

Interface

8-]55 CONFIDENTIAL

i

i

CONFIDENTIAL

PROJECT

GEMINI

SEDR 300

The following PRO instruction programming is associated with the PCDP interface:

Si_/e-I

Address X

Y

Computer malfunction

4

3

Computer running

5

0

Reset start computation

2

6

The computer inputs from the PCDP are m_._,_rizedas follows:

(a)

Computer on (XHONP) and computer off (XHOFF) - These signals from the COMPUTER ON-OFF switch control computer power.

(b)

Computer mode - The computer receives three binary coded discrete signals from the COMPUTER mode switch, to define the following operational modes:

Mode

Computer Mode i (m_Sl)

Computer Mode 2 ,(XHMS2)

Computer Mode 3 _Xm_3)

Pre -launch

0

0

I

Ascent

0

i

0

Catch-up

0

i

i

Rendezvous

i

0

0

Re -entry

i

0

i

(c)

Start computation (NNSTC) - This signal from the START pushbutton switch starts the closed-loop rendezvous operation and initiates re-entry calculations.

8-1% CONFIDENTIAL

CONFIDENTIAL

SEDR 300

Id)

Malfunction function pilot

(e)

reset

(_ST)

SESET switch uses

the

- This

signal

the

c_uter

resets

swit@h to

Abort transfer (XH_T)

test

for

fr_

the

c_puter

malfunction

a _ransient

mal-

latch.

The

failure.

- The signal aut_natlcally switches the

cc_puter from the ascent mode to the re-entry mode.

(f)

Fade-in descrete (_HS_) to the ac_ulator

(g)

The computer

via the discrete i_Lputlogic.

28 vdc unfiltered (_P28rmF)

outputs

(a)

- This signal fron a relay is supplied

to

the

PCDP are

s,_m_-_rized

as follows:

- This pr(,_-controlled

CcRputer r-n_Ing (_)

signal lights

the computer r,_nningl_mp which is tu:edas follows:

(1)

Pre-launch:

The COMP (c_]_uter x-m-_ng) lamp re_ains

off during this mode, except during m_ssion simulation I when its operation is governed by the mode being simu_ted,

(2)

Ascent:

i

The CaMP lamp turns on following Inertial i

Pl_tform release.

The lamp remains on for the duration

of the mode, and then turns off.

(3)

Catch-up: button duration

The caMP lamp l_ghts [

switch

is

of the

depressed

the

START push-

i The lamp remains ! mode_ ana then turns off.

8-157 CONFIDENTIAL

after

on for

the

CONFIDENTIAL

PROJECT

(4)

Rendezvous: button

GEMINI

The COMP

switch is depressed.

mode, operation readings when

(5)

Re-entry:

in this mode.

switch

is depressed

calculations

malfunction

built-in

(c)

Switch

lamp.

timing

the COMPUTER malfunction

Incremental

Velocity

The IVI contains

three

along the s_acecraft

Power

is

applied

to

the

IVI

- This

the computer

(SXDHSME) switch,

RESET

switch.

off

- This

and then turns

signal turns diagnostic

computation

off.

on the com-

program,

actuates

dc excitation

the START

The lamp remains

a

the signal.

is suppled

to

switch and the

(M),,, (,Figure 8-_0),

incremental

ments

The lamp turns

to zero.

of the mode,

check, or an AGE command

mode

Indicator

by the radar

or when time to start

is equal

(XCDMAL-A)

Either

excitation

of the

is terminated.

on for the duration

puter MALF

For the remainder

The COMP lamp lights when the START push-

re-entry

Computer

the START push-

of the 1Amp is dictated

that occur

the mode

button

(b)

lamp lights after

velocity

counters

that display

velocity

incre-

(body) axes.

whenever

the

computer

the

application

is

turned

on.

During

the

first

\

30-second cally

period

references

recognizing

(or

less)

its

counters

computer

following to

zero.

After

signals.

8-158 CONFIDENTIAL

this

of period,

power, the

the

IVI

M

is

aut_ticapable

of

CONFIDENTIAL .V-_

SEDR300

DIGITAL

COMPUTER

INCREMENTAL INDICATOR

VELOCITY

xwxwI -X DELTA VELOCITY

(XCWXVM)

X SET ZERO (XCDVIXZ)

I I J

CHANNEL

I

PROCESSOR

CHANNEL Y SET ZERO (XCDVIYZ) +Y

DELTA VELOCITY

-Z DELTA VELOCITY

(XCWYVP)

|

I

(XCWZVM)

Z AXIS CHANNEL

Z SET ZERO (XCDVIZZ)

'

DISCRETE OUTPUT LOGIC

-I

.--_

' DISCRETE INPUT LOGIC

1-

I

I !

Y ZERO INDICATION

(XVVYZ)

Z ZERO INDICATION

(XVVZZ)

X ZERO iNDICATION

(XWXZ)

I = _'

1 I

DC RETURN (XCDCRT)

1

+27.2

i

VDC (XSP27VDC-B)

RETURN (XSSVDCRT) I

J

I

+5 VDC (XS5VDC)

PROM IGS POWER SUPPLY

Figure

8-40

Computer-IVI

Interface i !

8-159 CONFIDENTIAL

i

I

m

CONFIDENTIAL

PROJECT-'G'EMINI ____

SECIR 300

The M _it,

counters

by means

or they can be set aut_atic-1_y

i_it_1_y These

can be set manually

set, _ey

p-!_es

cca_uter

l_rmits

set zero lines.

t_le computer

tion and dlspl_

The followi_

counters

A feed-back

CI_ instruction

velocity

kuobs

on the front

of the

After

the counters

are

pulses

displ_ed

signal, counter

from the c_er.

by the counter.

to zero by providing

to test for the proper

of a computed

velocity

the indications

can set the individual

each of three

by the cc_puter.

are driven by incremental

are used to _date

of control

denoting

The

a 20 usec pulse zero counter

reference

prior

on

position,

to the inser-

increment.

progr_-.,i.ng is associated

Signal

with the IVI interface:

Address

x_ X zero indication

i

3

¥ zero indication

5

2

Z zero indication

6

2

Velocity

2

2

The following

error count not zero

PRO instruction

progr_m_

is associated

Sisal

with the M

A_dress

x_

X

X counter

2

i

Select Y counter

3

I

Drive

counters

1

i

Write

output

5

3

Select

to zero

processor

8-16o CONFIOENTIAL

interface:

CONFIDIENTIAL

SEDR 300

_| i

i

The computer

supplies

_hree

s_nAl_

to

I1/I,

the

one

_or

each

counter,

that

are

i i

used

to

position

the

sets DOll minus

counters

to

zero.

To generate

and sets DO12 and D013

these

signals,

the

as follows:

X set zero

Minus

Plus

Y set zero

Plus

Minus

Z set zero

Minus

Minus

The IVI provides

three

feed-back

program

signals

to the cc_uter

D.125,

(DI31,

and D126)

!

to indicate

that the counters

are zeroed.

The program i

tests

the individual

i counters

for zero position

before

attempting

to drive

them to zero.

; The output processor increments line

provides

a timed

along the spacecraft

is time-shared

two's-co_-_lement

output to the IVI that

axes.

One output

c_annel i

represents

velocity

(phase 2) on the dels_

among the X, Y_ and Z counters.

form)

are written

on the del_y

! Incremental velocities (in i I line during phase 2 from acct_-

J ulator

bit positions

are set no more than

S_ and i through i ms before

12.

Discrete joutputs DOI2

the PROB5

operation,

select

and DOI3,

the proper

which

velocity

signal as follows:

S

nal

X velocity

MinUs

Plus

Y velocity

Plus

Minus

Z velocity

M_nv_

Minus

s

Once data is written for data during

on the del_

line,

bit times BTI through

the output

BTI2.

Of the del_y

Any bit sensed

8-161 CONFIDENTIAL

i

line

during

is sensed

this

time in-

CONFII)imNTIAL

PROJECT

GEMINI

SEDR 300

dicates bit

the

presence

(BTI_)

during

and a pulse

is

phase

Zf the is

_

buffer

the is

recirculated

addressed

set

The c_uter

zero

(a)

if

the

data during

affecting

velocity

se_

s_proximate_y

either

and a count

plus

the

_0_ate

cycle,

the

data

The zero

During

this

offt

velocity

added to

on the

output data

sign

ms

by a count

magnitude

the

21.5

either

the

is

every

of one is

decrease

_

with

or minus.

to

magnitude.

alcag

of

dels_

of the has

one. line

buffer

been

or

is

count-

can be processed.

is at the zero position.

Y zero indication (XVVYZ) - The down level signifies that the Y chanis at the zero position.

Z zero indication (XVVZZ) - The down level signifies that the Z channel of the M

is at the zero position.

The cc_puter outputs to the M

(a)

s_led

a buffer

X zero indication (XVVXZ) - The down level signifies that the X chan-

nel _f the M

(c)

is

into

inputs fr_n the IVX are su_aarlzed as follows:

nel of the M

(b)

its

discrete

next

is

buffer

line zero

t"_en gated

buffer

initiated

When this

and the

is

is

delay to

which This

cycle

without

as DI_.

ed down to

2.

generated

ssme time 2 an update subtracted

of data

are s_narized

sa follows:

+X delta velocity (XCWXVP) - The up level denotes that the X channel should change by one foot per second in the fore direction.

(b)

-X delta velocity (XCWXVM) - The up level denotes that the X channel should change by one foot per second in the aft direction.

8-162 CONFIDIKNTIAL.

CONIFIDI_NTIAL

SEDR 300

(c)

X set zero

(XCDVIXZ)

- The up level

drives

the X channel

to the

zero position.

(d)

+Y delta velocity nel should

(e)

(f)

(XCg_/VP) - The up level

change by one foot per second

-Y delta velocity

(XC_T/VM) - The up level

nel should

by one foot per

change

denotes

that the Y chan-

in the right

denotes

direction.

that

the Y chan-

second in the left direction.

Y set zero (XCDVIYZ) - The up level drives the Y channel to the zero position.

(g)

-Z delta velocity

(XC]¢ZVP) - The up level

denotes

that the Z chan-

i

_-_

nel should change by one foot per second in the down direction.

(h)

-Z delta velocity channel

(i)

should

(XC%IZVM) - The up level

denotes

change by one foot pe r second

that

the Z

in the up direction.

Z set zero (XCDVIZZ) - The up level drives the Z channel to the zero position.

Instrumentatlon The

computer

ditioning provided

S_stem

is interfaced

equipment

computer

8-41)

with the multiplexer

of the Instrumentation

to the signal

sent upon request

Certain

(Figure

conditioning

data,

System.

equipment,

to the multiplexer

as described

encoder

encoder

and

unit and the signal

COntinuous stored

analog

digital

con-

data is

quantities

are

unit.

below,

is continually

signal

conditioning

made

available

to the

i

signal

conditioning

data for multiplexing

equipment.

_e

and analo6-to-digital

conversion

unit. 8-163 CONI=IDI=NTIAL

equipment

conditions

by the multiplexer

this

encoder

CONFIDENTIAL i_.-_

SFDR 300

DIGITAL

COMPUTER

INSTRUMENTATION SYSTEM

PITCH ERROR (XCLPMBD)

=

RETURN (XCLPMBDG) ROLL ERROR (XCLRMBD) LADDER LOGIC

m

RETURN (XCLRMBDG)

m

YAW ERROR (XCLYMBD)

l

RETURN (XCLYMBDG)

SEQUENCING CIRCUITS J

=

POWER

I

SIGNAL CONDITIONING EQUIPMENT

COMPUTER OFF tXCEOPFD)

COMPUTER MALFUNCTION SEC. STAGE ENGINE

(XCDMALD)

CUTOFF (XCDSSCRT)

COMPUTER MODE I (XCDMSID) COMPUTER MODE

2 (XCDMS2D)

COMPUTER MODE 3 (XCDMS3D) + 27.2 VDC (XCDP27D) DISCRETE OUTPUT LOGIC

+ 9.3 VDC (XCDP9D)

SSHFT ULS S XCOAS:1P

RETURN (XC DASSPG) IS DATA (XCDASD)

RETURN IXC DAS DG)

-F 8 VDC



+8VDC



J

ENCODRR 15DATA SYNC EXCIT. (XCDTDSE)

INPUT LOGIC

IS DATA SYNC

(XTDS)

IS REQUEST EXCIT. (XCDTRQE)

Figure

8-41

Computer-IS 8-164

CONFIDENTIAL

i

Interface

J

MULTIPLEXER

CONFIDENTIAL

PROJEI (a)

Computer

modes -

monitored

The mode

to determine

signals

that the computeri

for a partlcularoperational

(b)

Computer

input power

the computer

(c)

Computer

mission

- The 27.2

by the IGS Power

running

transmitted

was in the correct

are

mode

phase.

vdc and 9.3 vdc inputs

Supply

- The computer

to the computer

are monitored

running

discrete

supplied

to

via the computer.

output

is monitored

and recorded.

(d)

Computer

malfunction

monitored

(e)

Attitude

data word

of Instrumentation the computer

The following System

mode

malfUnction

errors:

yaw,

and roll ac analog

and recorded.

locations

System

The pitch,

output

in the computer

data.

Data

attitude

errors

stored

memoryiare

in these

allocated

locations

for the storage

is dependent

upon

of operation.

CLD instruction

programming

is associated

with the Instrumentation

interface: Address X m

Y

Instrumentation

System

request

7

0

Instrumentation

System

sync

2

1

The following

is

!

Signal

PRO instruction

progr_ng

is associated

f

System

discrete

and recorded.

are monitored

Twenty-one

- The computer

interface:

8-165

CONFIDENTIAL

with

the Instrumentation

CONFIDENTIAL

PRINI SEDR 300

Si_al

Address

Instrumentation control

Every

System

input

gate

(DI07).

sync discrete

(a)

program

If the discrete

input

DII2 m_nus

- The program

21 locations.

mode,

input

is given.

This instruction bit positions

supplied

by one and the contents

(a)

buffer

location

instructions.

advance

the program

quantities

System

are placed correin o con-

shift pulses

System.

sequential

counter

counter buffer

is incremented location

Instrumentation

until

all

are

System System

21 Instrumentation

are tranmuitted.

System

request

8 -166 CONFIDENTIAL

System

(XTRQ)

of

23 to be

Twenty-four

program

Subsequent

inputs from the Instrumentation

Instrumentation

buffer

Then a PROIO

S, and i through

System.

of the next

according

of the data word

in the accu_nulator and sent to the Instrumentation

via the PROI0

The computer

request

causes the information

to the Instrumentation

- An Instrumentation

values,

System memory

of the accumulator.

are also

System

System

the Instrumentation

specified

so that the sign position

to the Instrumentation

requests

current

of the first

supplied

placed

minus,

in an Instrumentation

in accumulator

DII2 plus

is tested

stores

sponds to the sign position

(b)

i

tests the Instrumentation

The contents

in the accumulator

tained

0

(DII2) is tested as follows:

to the computer

struction

Y

System

50 ms or less, the computer

discrete

x_

are svmmarized

- An up level

as follows:

on this line

CONFIDENTIAL

PROJECT

GEM!

..,oo

N| ;

signifies that the Instrumentation System requires a computer data i word.

The word is transferred from the computer within 75 ms of i the request. Requests can occur at rases up to I0 times per second.

(b)

Instrumentation System data sync (XTDS

- An up level on this line

signifies the beginning of the Instrumentation System data transfer operation.

The computer outputs to the Instrumentation System are summarized as follows:

(a)

Instrumentation System shift pulses (XCDASSP) and return (SCDASSPG) ! This series of 2_ pulses causes Instrusentation System data to be I !

transferre_

(b)

to the Instrumentation

System buffer.

Instrumentation System data (SCDASD) and return (XCDASDG) - These ! l 2_ hits of data are transferred1in synchronism with the Instrumentation System shift pulses.

(c)

Instrumentation

System request excitatlon (SCDTRQE) - This +8 vdc

signal is the excitation

for the Instr _entation

System request

signal.

(d)

Instr_aentation System data sync excitation (SCIEDSE) - This +8 i vdc signal is the excitation for the Tnstrumentation System data sync signal.

(e)

Monitored signals - The following signals are supplie& to the iI Instrumentation System for monitoring purposes: i (i)

Pitch error

(X_)

an_ return (XCI_MBDG) i

8-167 CONFIDENTIAL

i !

CONFIDENTIAL SEDR 300

PROJECT GEMINI

DIGITAL COMPUTER

AEROSPACE GROUND EQUIPMENT

DIGITAL

COMPUTER

AGE REQUEST (XURQT)

AGE INPUT DATA (XUGED)

DISCRETE INPUT LOGIC

MARGINAL

TEST (XUMRG)

m UMBILICAL DISCONNECT



CONTROL LOGIC J

SIMULATION

(XUMRDC)

MODE COMMAND

(XUSIM)

COMPUTER HALT (XUHLI) _

RETURN (XS26VAC RT)

I

26 VAC (XS26VAC) +28 VDC FILTERED (XSP28VDC)

AGE DATACLOCK(XCDGSEC)

,

RETURN (XSP28VDCRT) FROM IGS

AGE DATA LINK (XCDGSED) DISCRETE OUTPUT LOGIC

COMPUTER MALFUNCTION

AUTOPILOT

SCALE FACTOR

• (XCDMALT)



(XCDAPSF)

=l

SEC. STAGE ENGINE CUTOFF (XCDSSCF) m i

+27.2

VDC (XSP27VDC)

RETURN (XSM27_/DCRT)

+20 VDC (XSP20VDC)

+9.3

VDC (XSPgVDC)

POWER LOSS SENSING

PITCH ERROR (XCLPDC)

ROLL ERROR (XCLRDC)

LOGIC LADDER

m

YAW ERROR (XCLYDC)

POWER SUPPLY

(XQBNEI)

FROM AUX. COMP. POWER UNIT

+28 VDC UNFILTERED (XSP28UNF)

11

,_

ABORT TRANSFER (XHABT)

(

CONTROL AND FROM PILOT'S

_

FADE-IN

I

DISPLAY PANEL

DISCRETE (XHSFI)

RETURN (XCLDCG)

+25 VDC (XCP25VDC)

-25 VDC (XCM25VDC) POWER REGULATORS

+8 VDC (XCPSVDC)

RETURN (XCSRT)

=--

A

m

Figure

8-42

Computer-AGE 8-168

CONFIDENTIAL

Interface

CONFIDENTIAL

_.

SEDR300

(2)

Roll

error

(SCIP_BD)

and retur_

(X_)

(3) Y_ e_or(xcT.-_mD) andre_i (X_) i

(_)

Computer off

(XCEOFFD)

i

(_) C_ter ma_u_otlon(XC_T_)i (6)

Second stage engine cutoff (XCDSSCPr)

(T)

Computer mode i (XCDMSID)

(8)

Computer mode 2 (XCDMS2D)

(9)

Computer mode 3 (XCSMSSD)

(zo)+zr.2 vdc(XCDPZrD) (ll) +9.3 vdc (XCDPgD) Aerospace

,Grcund Equipment

(AGE) Figure 8-_2)

The AGE determines spacecraft-installed computer stat_s by being able to read and i display the contents of any memory location, initiate i _nd terminate marginal tests of the memory timing, and co._and the computer to con_tion

the computer malfunc-

i

tion circuit.

These tests are accomplished by a hard-wlred computer/AGE data !

llnk. i

In conjunction with a voice link to the spacecraft, the AGE can control the I various computer modes of operation to determine the _tatus of the computer and its interfaces. computer

To aid in localizing failures, the AGE monitors the following

signals: (a)

All input and output voltages _

(b)

Second stage engine cutoff

(c)

Autopilot scale factor

(d)

Roll error command

(e)

Yaw errorcommand

(f)

Pitch error command

(g)

Computermalfunction

(to _tan

_.

Autopilot)

i!

In addition, the AGE provides two hard-wlred inputs to the computer to reset the malfunction memory

circuit and halt the computer and to forcei a marginal

t_m!ng.

check of the

Early and late strobing of the memory iis effected using the corn8 -169 CONFIDENTIAL

CONFIDENTIAL

PROJEMINI _.

$EDR300

puter/AGE data link.

The following CLD instruction progra_n_ng is associated with the AGE interfaces: Signal

The following

Address X

Y

AGErequest

2

3

AGEinput data

7

2

Simulation mode CO.And

_

2

Umbilicaldisconnect

6

3

PRO instruction

progr_-._ng

is associated with the AGE interface:

Signal

Address X

Y

AGEdatalink

2

2

AGEdataclock

3

2

Computer m_ifUnction

4

3

Memory strobe

0

6

Autopilotscalefactor

1

6

Second stage engine cutoff

4

6

The AGE program commences when the AGE request (C132) is tested minus.

To receive

the 18 bit AGE data word, the program repeats the following sequence of operations 18 times:

(a) Turn on AGE data clock (D023)

(b) Wa t

8-17o CON FIDINTIAL

CONFIDmNTIAL

SEDR300

(c)

Reset AGE data clock

(D023)

(d) w_t Z._mB (e) _eadAG_inputdata(Dx2?) (f) w._tz._ ms The

above sequence

causes

the 18-blt

ter and Into the computer. the r_ining

i_ bits

The first _ bits

are data.

The coding

of the _E

out of the AGE regis-

word

of the _ mode

are mode

bits

Bits

0

0

0

0

None

0

0

0

1

Read ar_ word

0

0

i

0

Set marginal

earl)-

0

0

i

i

Set cumputer

malfunction

0

I

0

0

Set marginal

late

0

i

0

i

Set pitch

0

i

i

0

Set yaw ladder

0

i

i

i

Set roll ladder

i

0

0

0

Set all ladder

the I_ data bits

ladder

of the AGE word

output output outputs

are as follows:

15

Z_ 13

12

LI

l0

9

s5

s3

s2

Sl

A8

A7

A6

A5 A_ A3 A2

A9

A8 define the address

clock pulse

timing,

of the requested

Sl throush

S_ define

8

8-ZTZ i

7

6

5 A1

data, A9 sets up AGE

the sector

CONI_IO=NTIAL

on

output

16

where A1 through

s/id

Mode

Z8 lT s_

bits,

is as follows:

Mode

In the read any word mode,

internal

AGE word to be shifted i

of the requested

CONFIDENTIAL

SEDR300

data,

and

S5 defines

mines

the

requested

located bit

in

of

syllable

data

the is

times.

data

syllables

requested and

the

and

is

last

13

bits

sent

to

the

There

is

(a)

Set

(b)

Turn

it

are

syllable

data

from

_-5

requested

the

sent

AGE.

to

the 2_

the

the

data. the

If

bit

the

13 bits

first

following

of

the

syllable

bit

clock

to

18

If

AGE are

first). of

is

high-order

0.

sent

deter-

data

with

sequence

resetting

computer

requested

2 (high-order

ms between

The

AGE starting

iOn-order

syllable

executing

of

the

to

with

in

AGE by

a dels_

it is

finishing

located

of

sends

0 and 1,

1 and

data

syllable(s)

____

O's,

Requested

operations and

the

setting

26 clock

19. AGE data

link

on AGE data

(D022) clock

from

accumulator

sign

position

(D023)

....

(c) wait2.5 ms Reset AGEdataclock(D023)

(d)

(e) waitz ms (f)

Reset

AGE data

link

(I)022)

(g) waiti ms In the set marginal _unction

with the marginal

of the co_uter

malfunction

test

sets DO60 on.

signal provided

This

signal,

by the AGE, causes

early

in constrobing

memory.

In the set computer

m-leunction

on mode_

the computer

sets D03_

on to check the

indication.

In the set marginal Junction

earl_ mode, the computer

late mode, the computer

with the marginal

test signal,

sets D060 off.

causes late strobing

memory.

8-m72 CONFIDENTIAL

This

signal,

in con-

of the computer

CONFIDENTIAL

SEDR 300

In the set ladder outputs modes, the i_ data bits of the AGE word are as follows:

18

17

16

15

i_

13

12

S

D6

D5

D4

D3

D2

D1

]I

io

9

8

7

6

5

0

0

0

0

0

0

0

where D1 throuEh D6 are data bits and S is the sign bit.

The data and sign bits

are used to control the ladder outlmr_indicated by the i4 associated mode bits. The nmnber is in t_o's-cumplement form where DI is the iow-°rder data bit.

The computer inputs from the AGE are su_.arized as follows:

(a)

AGE request (_)

- An up level signifies that the AGE is read_ to

transfer a message to the computer.

(b)

AGE input data (XUGED) - An up level denotes a binary i being tr,n-ferred from the AGE to the cumputeri

(c)

Marginal test (XI_dRG)- An up level, in conjunction with the proper AGE message_ causes the ccm_uter m_mory Liming to be m-_gin-lqy tested.

(d)

Umbilical dlscomnect (_DC)

- An open circuit on this line signi-

fies that the Inertial Platform has beenireleased (or that the torquing signals have been removed).

The Inertial Platform then

enters the inertial mode of oper_ion

and the ccmrputerbegins to

perform the navigation guidance portion of its ascent routine.

_-

(e)

Simulation

mode ec_ud

(XUSIM) - This

c_end

causes

the

c_uter

to operate in a slmulated ,-ode as determined by the COMP_I_R mode switch. 8-173 CON_'IDENTIAL

CONFIDENTIAL

SEDR 300

(f)

Computer halt (XU}_T) - An up level resets the computer malfunction circuit and sets the computer halt circuit.

The computer outputs to the AGE are summarized as follows:

(a)

AGE data clock (XCDGSEC) - This line reads out the AGE register and synchronizes

(b)

AGE data link (XCDGSED) - An up level denotes a binary l being transferred

(c)

the AGE with the AGE data link.

from the computer to the AGE.

Computer malfunction (XCDMALT) - An up level indicates that the computer malfunction latch is set.

The latch can be set by the computer

diagnostic program, a timing error, program looping, or an AGE command.

(d)

Monitored signals - The following signals and voltages are supplied to the AGE for monitoring or recording purposes:

(i)

Autopilot scale factor (XCDAPSF)

(2)

Second stage engine cutoff (SCDSSCF)

(3)

Pitch error (XCLPI_)_ l

(5) (4)

Rollerror error(XCLYDC) (XCLRDC) Yaw

_

and common return (XCLDCG)

(6) +25v c(x P2mc (8) +8 c (xcPSV ) (7) -25vde (XCM25VDC)_

8-1"_ CONFIOIEN'rlAL.

and co_on return (XCSRT)

8-175 CONFIDENTIAL

CONFIDENTIAl-

PROJECT

GEMINI

_SEDR 300

__

SYSTEM _SCRXPA_ _ Purpose... The Manual Data consists

Insertion

of the Manual

(Figure 8.dl_), The MI_U

Unit, hereinafter

Data Keyboard

hereinafter

enables

referred

the pilot

referred

(Figure

8-43)

to as the _fl_U, physically

and the Manual

Data Readout

to as the MDK and the MIIR, respectively.

to insert data into,

and read data from, the com-

puter memory.

rfo ee Data Insertion Before cleared

data is set up for insertion from the _

by pressing

Then the data

insert push-button

digit decl,ml

nmaber.

of the computer five digits

cally supplied the address on the MDR. pressed

Data Before

to

the CLEAR switches

The first two

memory

specify

into the computer,

location

the data itself.

to the computer

store

the

data

in

from

the

the

on the _

switch

the data

data

is

on the MDR.

are used to set up a 7-

from the left specify

the address

is to be stored,

and the last

As the data is set up, it is automati-

accumulator.

and data is made by means After verification,

push-button

digits

in which

all existing

A digit-by-digit

of the ADDRESS

and MESSAGE

the ENTER push-button selected

memory

verification

switch

display

of devices

on the MDR is

location.

Readout data

is

MD_U by pressing

read the

computer,

CT._AR push-button

all

existing

switch.

CONIPlOIN'rlAI..

data Then

the

is data

cleared insert

from push-

the

CONFIDENTIAL __.

SEDR 300

PROJECT

____

GEMINI

•,=,"_

=

LEGEND

t1_Mi

NOMENCLATURE

_

DATA INSERT PUSH-BUTTON

CONNECTOR J1

Q

Figure

8-43 Manual

Data

IDENTIFICATION

Keyboard

8-177 CONFIDENTIAL i

PLAI'E

SWITCHES

CONFIDENTIAL

__

PROJECT

SERIALW0

GEMINI

PARTN0

L_I_'ERNAT_NAL BUSINESS MACHINES CORP U¢0ONNKU. SCO MOe_L CONTACT MANUAL ....

_--]

iTEM

DATA uS READOUT

NOMENCLATURE

LEGEND DISPLAy DEVICES MESSAGE

0

ADDRESS AND

Q

ENTER PUSH-BUTTON

(:_ 0

READ OUT RUSH-BUTTON SWITCH CLEAR PUSH-BUTTON SWITCH PWR (POWER) TOGGLE

Figure

8-44 Manual

(_

CONNECTOR

O

IDENTIFICATION I

Data Readout

8-178 CONFIDENTIAL

SWITCH

SWITCH

JI PLATE

CONFIDENTIAL-

SEDR 300

button

switches

specify

the

read.

are

used

address

of

the

A digit-by-digit

ADDR_S on the

display MDR is

and

displayed

__

Physical

devices. pressed by the

computer

memory

After and

the

of

is

The _

the

dlspl_

address

from

External

Controls

and

and describes

made

READ _'_ the

data

digits

is

by moans

to

of

push-button

Selected

be

the switch

memory

location

devices.

wide, and 5.51 inches

inches high,

characteristics

8-45.

which

two

deep.

on Figure

It weighs

8-43.

The

1.36 pounds.

major

external

charac-

legend.

Description

external

The controls

is

The

Description

is 3.26

3.15 pounds.

from

the

read

n_mber.

location

verification, data

_n_SAGE

deelual

are s,,,,_rized in the accompanying

Physical

SYSTEM

up a 2-digit

views of the MEK are shown

teristics

Figure

set

verification

The MIE is 3.38 inches External

to

5.01 inches wide,

views

and 6+41 inches

of the MDR are shown

are s,-m-rized

on Figure

in the accompanying

deep.

8-44.

It weighs

The major

legend.

Indicators and indicators

located

The accompanying

on the MDK and MDR are illustrated

legend

identifies

the controls

on

and indicators,

their purposes.

OPERATION

Power The MDIU This

receives

all of the power

power consists

required

of th e following

for its operation

regulated

8-179 CONFIDENTIAL.

dc voltages :

from the computer.

CONFIDENTIAL SEDR300

.,----.

o c•o

LEGEND ITEM

NOMENCLATURE

PURPOSE D_SPLAY ADDRESS AND MESSAGE SENT TO COMPUTER DURING

O

Q

Q

ADDRESS AND MESSAGE DISPLAy

ENTER PUSH-BUTTON

SWITCH

CLEAR PUSH-BUTTON

SWITCH

READ OUT PUSH-BUTTON

Q

(_

PWR (POWER) TOGGLE

DEVICES

SWITCH

Figure 8-45

DURING OPERATION TO BE STORED IN MEMORY. PROVIDESENTER MEANS FOR CAUSING MESSAGE SENT TO COMPUTER UP BY MDKMEANS TO BE CLEARED OR CANCELED. PROVIDES FOR CAUSING ADDRESS AND MESSAGE SET

SWITCH

DATA INSERT PUSH-BUTTON

ENTER OPERATION; DISPLAY DURING ADDRESS READOUT SENT TO, OPERATION. AND MESSAGE RECEIVED FROM, COMPUTER

SWITCHES

Manual

OF COMPUTER ANDFOR DISPLAYED MESSAGETODISPLAY PROVIDES MEANS CAUSING BY MESSAGE BE READDEVICES. OUT POWER TO MEANS MDK AND PROVIDES FORMDR, CONTROLLING

APPLICATION

OF

PROVIDE MEANS FOR CAUSING ADDRESS AND MESSAGE TO BE SENT TO COMPUTER TO BE DISPLAYED BY ADDRESS AND MESSAGE DISPLAY AND DEVICES.

Data Insertion Unit Front Panels 8-180 CONFIDENTIAL

CONFIDENTIAL

PROJECT

.,

(a)

+25 vdc

_

(b) -25 (c)

it is not actually

filtered

on.

and common

return

J

+8 vac and return

This power is available

is turned

GEMI

SEDR300

at the MDIU whenever

applied

When

to the MDIU

power is turned

by a capacitor

network

the computer

circuits

until, the PWR

on at the MDR,

and supplied

is turned

on.

However,

switch on the MDR

the regulated

dc voltages

are

to the MDK and MIR circuits.

Flow (n re 8-6) The MDK has ten data select

the address

or from which are numbered

insert

of a computer

to binary

values,

called the insert

in the computer.

coOed decimal

(Figure

values

button

display

devices

push-button

switches

data

insert

push-button

switches

The command

push-button

switches,

the

data

switches

that

has

all

supply

are used to

data is to be stored

data, !the push-button

encoder

is used

switches

to convert

their

can be used by the computer.

are supplied Ito the insert

encooer

also

input

devices

are used to display on the MDK,

develops

logic of

set

inputs

up is to

the

and three

These

serializer

the data available

the computer.

called H_TER, into be

discrete

input

8-181 CONFIDIENTIAL

switches. insert

the data set up by the

from a computer

memory

location.

READ !OUT, and CT._4R, are used

or read

cleared

push-button

Set up by the data

either

or the data read

to

Cnmm"nd

the address

and to display

data is entered

been

in Which

that

switches

8-47)

The display

whether

location

to the discrete

The I_R has seven digital

to determine

These

For storing

data signals,

The insert

is supplied

Flow

switches.

the insert button

outputs

M_R.Data

memory

data is to be read. decimally,

signal which

push-button

(or

out of the computer, canceled). logic

of

These the

computer.

or whether

push-button Since

CONFIDENTIAL

_-_

PROJECTSEDR 3OOGEMINI

_,_.._.

DATA INSERT SWITCHES

J_

O

;

_

2

,

_-

/

ZERO

C

_

C

_

C

_

I

AVAILABLE CIRCUIT DATA

__1

• I

INPUT LOGIC TO DISCRETE

|

_

CIRCUITINSERT DATA l

_

INSERT DATA 2 CIRCUIT

3

:



4

• 5 ;



O

INSERT BUTTON ENCODER

L

I 1

8

O

C

_

Figure

_

8-46

Manual

INSERT DATA 8 CIRCUIT

Data

Keyboard

8-182 CONFIDENTIAL

Data

Flow

_, "--" TO INSERT ' SERIALIZER

CONFIDENTIAL

PROJECT

GEMINI

DRIVE

i

CONTROL CIRCUIT

i

i DEVICE SELECT CONTROL

I _

i

INSERT DATA 2

i

CirCUIT

I

CIRCUIT

U

J i

_

O_

_" U w O _ _ _- _ _

DEVICE b

_, N MBER

DEVICE

SELECT CONTROL 2 CIRCUIT

_

SELECT CIRCUIT

DISPLAY DEVICES

_

SE ECT CI CUlT

DEVICE SELECT CONTROL CIRCUIT

INSERT _

DATA 4 CIRCUIT

iNSE'RT 4

:

DATA 8 CIRCUIT

i I i I

i i

Ji READOUT

i rZZl

O

C

_ J CIRCUIT

J

CLEAR

O

C

-_

I

CIRCUIT

L

_

INPUT

LR_c_IC

TO D,SCR TE

ENTER

0

Figure

C

_

8-47 Manual

l,

Data Readout

Dat a Flow

8-183 CONFIDENTIAL

i I

CONFIDENTIAL

the

display

received

from

values and to

devices

from three

the

the the

device display

drive

is

outputs

number

display

control

The manual the MDIU

to

is

used

of

data circuits

device.

control

This

device

signal

from

coded

can

be

select the

conjunction

with

display

values

outputs

from

the

outputs

of

with

a particular by means

of the device received

is presented

supplied the

the

device.

A combination

is accomplished

coded decimal

is

of

is used in conjunction

operations

These circuits

display

selector.

values

displayed.

computer

a particular

to select

dect._l

control

A combination

device

selection

decimal

they

three

select

the

binary

before

circuit

the combined

the binary

in to

by means

drive

the

circuit.

circuit

and an equivalent

Data

decoded

Another

control

Thus, through

selector,

decoded

Manuel

device

be

display,

supplied

circuits

accomplished

of the display

selector.

are

drive

from the insert

selected

must

circuits.

control

device

selection

data device

select

a decimal

computer computer

insert

display

provide

This of

the outputs number

on the

of the number

selector

and the

from the computer

are

on the display

devices.

is transferred

between

Subroutine data subroutine,

and the computer,

in the DIGITAL

CC_ER

which

determines

is described

SYSTEM

when data

under

OPERATION

part

the Operational of this

Program

heading

section.

Interfaces The MDIU under

interfaces,

the Interfaces

all of which heading

are made with the computer,

in the DIGITAL

CC_fl_u_ERSYSTEM

this section.

8-184 CONFIDENTIAL

are described

OPERATION

part

of

CONFIDENTIAL

PROJMINISEDR300

___

AUXILIARY SYSTEM

TAPE M_MORY

DESCRIPTION

General The Auxiliary system. program

It is used storage

over 85,000 puter

Tape Memory

in spacecraft

thirteen-bit

of the spacecraft

The ATM

is a self-contained

for the digital

core memory.

Physical

(ATM)

(Figure

through

computer.

words.

The ATM

eight

twelve

tape

to provide

It has a total

This is about

is mounted

magnetic

seven

on a cold plat(

additional

storage

;linesthat

recording

capacity

of

of the com-

in the adapter

section

8-15).

Characteristics is i0 inches

x i0 inches

It has three external

connectors

x 7 inches and weigh_ for its interfaces

25.7 pounds (Figure 8-48). i with the digital computer and

! the Pilots' initial

Display

and Control

pressurization

Panel

(PCDP).

of one atmosphere,

The AT M is hermetically

gage,

at ambient

room

sealed with

temperature

and

pressure.

Internally,

the AM

electronics

for the read, write

Functional

contains

a tape transport, an_ control

a driv, motor,

and the necessary

functions

Characteristics

The functional Tape

characteristics

of the ATM are _,-_nriZed

length

as follows:

525 feet I

i Tape type

3M type m-1353 i Heavy-du_

high

resolution

i _-

Instrumentation

tape

i

Tape

Read/write

speed.

- 1.5 ips +.0.5_

Wind/re'rid !

8-18_ CONFIDENTIAL

i

!

- 8 times

r/w speed

CONFIDENTIAL SEDR300

-_

__'__

PROJECT

ACCESS HOLES FOR MOUNTING

GEMINI

SCREWS

CONNECTOR

GROUNDING

)MPUTER AND CONTROL MOUNTING

SURFACE' NNECTC_

Figure

8-48

Auxiliary

8-186 CONFIDENTIAL

Tape

Memory

HOLE

CONNECTOR

CONFIDENTIAL

SEOR 300

Channels

16 (9 data, 3 parity, 3 clock, i spare)

Storage capacity

Total 12i.5x 106 bits (15 channels) Effective 90,000 iS-bit computer words

Storage density

133 bits_inch/channel

Data transfer rate

600 bits_second

Ready tide-per max program

i0 m_nutes (verify 3 syllables)

i

7 minutes

(reprogram 2 syllables)

Total rea_ time

67 minu_es

Total wind/rewind time Voltage

i0 minu_es max. i 21 - 30 v&c

Voltage interrupts

115 milliseconds

Controls and Indicators The controls and indicators associated with the ATM are _...arized as follows: (a)

AUX TAPE OFF - ON/RESET - A toggle

,vitch on the PCDP, used to i !

apply power to the A_

(b)

AUX _

or to reset St.

mode selector - A five - position rotary switch used

i to select an operational control mode for the ATM.

The five

mo_sare- (l) _BY, (2)A_O, (B)W_m, (_)RE_D _d (5)PROG (reprogram).

(c)

Manual Data Insertion Unit (MDIU) -iUsed to select one of three ATM operational sequences stored in!the computer memory. are:

(i) reprogram, (2) verify, an_ (3) reprogram/verify.

These

8-187 CONFIDENTIAL

CONFIDENTIAL

PROJE--C'-GEM __

IN I

SEDR 300

(d)

- Display tape position

Incremental Velocity Indicator (M)

words (on the IVl LEFT/RIGHT channel) and module words (on the M

(e)

FORE/AFT channel) during the A_

AUX TAPE RUN indicator - A lamp on the PCDP which ill_im_nates whenever A_

(f)

search operation.

motor power is applied.

AUX TAPE ERROR indicator - A lamp on the PCDP which illuminates when incorrect frame parity is detected by the ATM.

SYSTEM OPERATION

9eneral The A_4 is used to store operational program modules for in-flight loading of the spacecraft digital co_puter.

It is capable of replacing the majority of the data

in syllables zero and one of the computer memory (approx 8,000 thirteen-bit wor_s) in approximately seven m_nutes.

The program data is stored in the A_

by recording it on magnetic recording tape.

Normally, this data is supplied by the Aerospace Ground Equipment (AGE) and recorded (written) on the tape prior to launch time.

It is also possible, however,

to write data onto the tape using the MDIU and digital computer.

There are two methods of load_ng the computer memory from the ATM. the auto m_le and is considered to be the primary one.

The first is

The second is the manual

mode and is provided as a hack-up metho_ for loading the computer memory.

The

•asic difference between the two is that the auto mode requires fewer manual operations.

8-188 CONFIDENTIAL

CONFIDENTIAL

PROJECT s,o.3OGEMINI

The A_

employs

a reel-to-reel

combination

read/write

drive motor

accomplishes

head having speed

the phase

of one winding

(n_._nal)

is provided

wind/rewind

operation.

which

are eight

The oscillator The frequency

transport

with

by using

by

!A tape

modes

those

for the read/write by 8:1 through

speed

of i. 5 ips High

the drive motor

speed

a binary

speed

with a fre-

used for the read/write

the frequency

The

switch to switch

of operation.

by a tic-to-de inverter

output provides

and a single-

per track.

a s_lid-state

supplying

times

assembly

two windings

to the other.

read and write

is provided

source hut it is reduced

Write

respect

is accomplished

The drive system power oscillator.

with

drive

16 tracks

reversal

for both

operation

quency and voltage

peripheral

and a fixed

speed. frequency

for high-speed

o_iginates

from this

same

chain.

Electronics

Figure

8-_9

shows the A_

(Hon-Return-to-Zero)

write

data in serial

a parity bit)

together

with

The recording

circuits

convert

four-bit

frames

electronics.

in parallet

shift

form

pulses

input

accepts

four-bit

(one his in each four-bit

and frame

the serial

NRZ format

The A_

input

synchronizing i

clock

frame

is

pulses.

into iparallel form and record

on the m_netlc

tape.

Each four-bit

the

frame

i

plus a frame

synchronizing

tape by triple width

redundant

to minimize

errors

clock

pulse

is recorded

head drivers. introduced

Each

redundantly

on the magnetic

data bit is spread across

by tape flaws

or foreign

matter

the tape

on the tape

surface.

_ead

Electronics

The play-back

(read) electronics

write electronics.

Each data

(Figure

channel

8-50)

uses the same tape head as the

is read by a play-hack

8-189 CONF|DENTIAL

amplifier/level

CONFIDENTIAL

_REOGLISTE R

F_ou'_JT 7 REGISTER

POUR .'13"_U_FEr

_ __

J

INTERFACE

:

TRIPLE

TRACK 1

REDUNDANT

TR6

_ m

Dl D1

DRIVER HEAD

TRI1

_"

DI

DRIVER

TR12



D2

TR8

_

D3

TRI5

_

P

TR5

_

P

|

SHIFT

-

j

HEAD i

REDUNDANT

DRIVER HEAD

I

__,._

I

1

0I" I

L

NRZ DATA

ERAM/ [D3D2 ' l PARITY BIT

DI l_l

--

_n

FF

j_

TRWLE

J

COMPUTER

REDUNDANT --HEAD

DATA INTERFACE

DRIVER

CLOCK

t COMPUTER J J

INTERFACE

Figure

8-49

ATM

Write

Electronics 8-190

CONFIDENTIAL

Block

Diagram

_

IR4

=

C

TR9

_

C

TR14 READ/WRITE TAPE HEAD

_

C

CONFIDENTIAL SEDR 300

._ _

l_

Po,JcT VOTER

DI

_

D2

L

DATA I

_

_

PARITY _J

TAPE HEAD READ/WRITE

D2

_

D3

_

DAITA I

VOEER DATA 3

DATA 2

GENERATOR

_

: DA=TA 3

P_ p

PARITY VOTER

--

PAilTY COA_PARATOR

SET TAPE ERROR

i

P

_

t

ERROR INHIBIT

VOTER C _

-

CLOCK'

C



C

8-50

ATM

Read

Electronics 8-191

CONFIDENTIAL

Block

=

_

= CLOCK

I

Figure

_

Diagram

CONFIDENTIAL

PROJECT

detector, voted

and each redundantly

on (2 out of 3 majority

outputs

recorded vote)

data bit (DI, D2, D 3, P, C) is majority

by the A_

(DI, D 2, and ])3) and clock voters

amplifiers supplied

and,

subsequently,

to the computer).

generator.

The output

Each

bit read from the tape.

generated

parity

bit, the A_

the AUX TAPE ERROR

lamp on the PCI_.

those developed

computer output

generator

an A_

logic.

error

to output

is also

from the voted

bit is not

supplied

to a parity

wlth

parity bit differs discrete

by comparing

data bits

voted

interface

(the parity

which

A check for tape errors

of operation

Three

is then compared

If the recorded

issues

the wind and rewind modes

bits with

data voter

of the parity

voting

are supplied

to the digital

on parity

during

GEMINI

the votedfrom the

will ill-m4nate

is also performed

the recorded

parity

during playback.

Im_RFAC_S The A_I_ interfaces DIGITAL

CO_F_

|H,

with the digital

IN_FACES

co_uter

part of this

and the PCDP

section.

8-192 CONFIDENTIAL

are described

in the

CONFIDENTIAL

PROWl

___

YS_

VELOCIT_ INDICATOR

i i

SYS_

SEDR 300

IESCRIPTION

Purpose The primary

purpose

after referred velocity

of the Incremental

to as the IVI,

Velocity

is to provide

Indicator i

visual

(Figure

indications

8-51),

herein-

of incremental

!

for the longitudinal(forward-aft),laterall(left-rlght), and vertical l

(up-down)

axes

of the spacecraft.

sent the amount and direction achieve

correct

by means

_

mation

of additional

concerning part

velocities

to the existing

repre-

necessary

spacecraft

to

velocities

thrusters.

Tape Memory

the tape position

during

this usage can be found

of this

incremental

velocity !or thrust

use of the IVI is to display

from the Auxiliary

OPERATION

indicated

and thus are added

of the maneuver

An additional words

orbit,

These

words

its oper@tion.

and module

Additional

infor-

in the AI/_ [LIARY TAPE MEMORY

SYS_

section.

Performance A three-diglt

decimal

used to display

display

incremental

device

velocity

Both the lamps and the display

iiI

indication

for each of the ithree i

1.mps are

spacecraft

axes.

devices

switches

on the IVI or automatically

maneuver

thrusters

correct

and two direction

can be set up ieither manually by rotary J by inputs from the computer. Then, as the

the spacecraft

velocities i pulses

are received

from

i

the computer

which

drive the display

devices

toward

Zero.

If a display

device

is

! driven

beyond

zero, indicating

an overcorrection

of the spacecraft

velocity

for

i the respective

axis, the opposite

direction

indication

lamp lights

and the display

i

device

indication

increases

in magnitude

to show a velocity

direction.

8-193 CONFIDENTIAL

i

error

in the opposite

CONFIDENTIAL SEDR300

..___

_,--lrT'_t __

LEGEND

,_M

NO_NCLA_"

(_ Q

FWD_FORWARD_ DI_CTIO. ,NO,CATION L--P _O.ARO-APT O.F_AY.V'CE

Q

LEFT-RIGHT

Q

R (RIGHT) DIRECTION

(_

UP-DOWN

Q

UP DIRECTION

DISPLAY DEVtCE INDICATION

LAMP

DISPLAY DEVICE

INDICATION

LAMP

L-R ROTARY SWITCH

(_)

AFT-FWD ROTARY SWITCH

(_

AFT DIRECTION

(_) _

CONNECTOR IDENTIFICATIONJI

iNDICATION

O

O

LAMP

_0,

CONTRACT

'_/

PLATE

j_

_

,)

Figure

8-51

Incremental 8-194 CONFIDENTIAL

Velocity

Indicator

CONFIDENTIAL

PROJECII

Physics1

Description

The IVI is 3.25 inches B.25 pounds. summarized

Controls

The major

;.0_ inches wide,

external

in the accompanying

and 5.99 inches

characteristics

are

deep.

;hown in Figure

It weighs $-51 and

legend.

and Indicators

The controls

and indicators

The accompanying their

C

high,

legend

located

identifies

on the IVI are illustrated i the

controls

on Figure

i and indicators,

8-52.

and describes

purposes.

SYSTEM

OPERATION

Power The _Dower required Supply whenever

During

for operation

the computer

of the IVI is supplied

is turned

(a)

+27.2 vde and return

(b)

+5 vdc and return

the first BO seconds

(or less)

on.

by the IGS Power

The powerl inputs

following

are as follows :

the application

of power,

the

i

incremental

velocity

Thereafter,

the IVI is capable

Basic

counters

on the

IVI are automatihally

of normal

driven

to zero.

operation.

Operation

The IVI pulses display

includes

three

identical

channels,

for one of the spacecraft device

error pulses

axes

and its two associated

are either

received

each

of

and processes direction

which

accepts

them

indication

from the computer

velocity

error

for use by a decimal lamps.

o4 i generated

The velocity

within

the M,

i l

as determined With

by the position

the spring-loaded

of the rotary

switches

in their

switch aslsociated with 1

neutral

8-195 CONFIDENTIAL

center positions,

each the M

channel.

CONFIDENTIAL SEDR 300

"FWD"" J 1

I

[0oo1 [olc)lol [oool

LEGEND ITEM

(_

NOMENCLATURE

FWD (FORWARD) DIRECTION FORWARD-AFT

INDkCATION

UP-DOWN

LAMP

LAMP

LAMP

DISPLAY DEVICE

DN (DOWN)

DIRECTION

THAT PLUS X AXIS VELOCITY

INDICATES

INDICATES

OF INSUFFICIENT

OF INSUFFICIENT

THAT PLUS Y AXIS VELOCITY

INDICATES PLUS OR MINUS AMOUNT Z AXIS. OF INSUFFICIENT

LAMP

INDICATION

IS INSUFFICIENT. VELOCITy

FOR PLUS

THAT MINUS Y AXIS VELOCLFY IS INSUFFICIENT.

OR MLNUS YAMOUNT AXIS. INDICATES

iNDICATION

UP DIRECTION iNDICATiON

INDICATES

INDICATES OR MINUS XAMOUNT AXIS.

DISPLAY DEVICE

R (RIGHT) DIRECTION Q

INDICATION

DISPLAY DEVICE

L (LEFT) DIRECTION

LEFT-RIGHT

PURPOSE

VELOCITY

FOR PLUS

iS INSUFFICIENT. VELOCITY

FOR

INDICATES THAT MINUS Z AXIS VELOCITY IS INSUFFICIENT, LAMP

THAT PLUS Z AXiS VELOCITY

IS INSUFFICIENT.

Q

DN-UP

(_

L-R ROTARY SWITCH

VELOaEY ERROR ON PROVIDES MEANS FC_ LEFT-RIGHT MANUALLY DISPLAY SETTING DEVICE. UP Y AXIS

AFT-FWD ROTARY SWITCH

VELOCITY ERROR ON DISPLAYUP DEVICE. PROVIDES MEANS FOREC_WARD-AFT MANUALLY SETTING X AXIS

@

ROTARY SWITCH

INDICATES

VELOCITY ERROR ON DEVICE PROVIDES MEANS FORUP-DOWN MANUALLY DISPLAY SETTING UP Z AXIS

AFT DIRECTION INDICATION

Figure

8-52

LAMP

INDICATES THAT MINUS X AXIS VELOCITY IS INSUFFICIENT.

Incremental

Velocity 8-196

CONFIDENTIAL

Indicator

Front

Panel

CONFIDENTIAL

__

SEDR300

processes

only the pulses

switches

in either

replaces

them with pulses

pulses

beyond

direction

are generated

of rotation

until

generated

the rate reaches

fixed oscillator.

and replaces

oscillator

per second.

removes

them with

Rotation

the pulses

pulses

These

of the switches

generated

generated

and

13.5 degrees

by the

by an internal

at a rate

of the switches

beyond

the 50 pulses

per second position

of 50 pulses

per second.

is limited

by

stops.

pulse received causes

Simultaneously,

this

same pulse

lamps to light right,

on any channel,

the appropriate

the pulse;

count depending

or up direction

Each additional

A pulse having

a count

depending

of one.

direction

on a positive

is indicated,

pulse between pulse

the same

a pulse having

to display

or one of the

input

on which

indi-

line,

a

channel

and if the pulse was ireceived on a negative i

on the relationship

conversely,

received

is indicated,

and the sign of the added

is received.

device

the computer

one of the two associated

If the pulse _as

input line, an aft, left, the pulse.

from either

display

causes

or down direction

(X, Y, or Z) received

count;

variable

per second for every

I0 pulses

of the

from the computer

are generated

oscillators,

counters

rotation

pulses

The first

received

received

by an internal

position

However,

These

mechanical

forward,

the pulses

at a rate of one pulse

oscillator

Rotation

from the computer.

removes

the i0 pulse per second

variable

cation

received

either

depending

increases i

on which

or decreases

the sign Of the existing

as determine(

the

value

on the

by the line on which

sign as the existing

the opposite

channel

error

increases

sign ofi the existing

error

it the

decreases

i

the count.

A series

of pulses

having

the opposite

sign indicates

a corrective

i

thrusting causing direction

and eventually still more

reduces

pulses,

indication

causes

the indicated the count

error

to zero.

to increase

lamp lit.

8-197 CONt_IDIENTIAL

again

An overcorrection, but with

the opposite

CONFIDENTIAL SIDR 300

X CHANNEL

ROTARY -X DELTA VELOCITY

_ Z

SWITCH

fXDELTAVELOCJTY

_:

AFT

COUNTER

FWD

' J

_i ' ]

_ PULSE

_g_NR

MOTOR

[

I SET ZERO CONTROL

X ZERO INDICATION

I I I

D,S_Y Iololol

I

DEVICE

I OSCILLATOR

÷27.2v

J I I

X SET ZERO

I

DRIVERS

- l

J

=

I

DRIVER

FIXED

t

l

I

[

il

li I

I 1 I

EORWARD-AE, "

X ZERO IND.

l

_+27.2V

FWD

VARIABLE OSCILLATOR

|

LAMP DRIVER "l-SV

-"

_

J

SELECTOR

AFT

i "_

_ LAMp

_'

kAMP DRIVER _

+SV

IO'4:_OM Y AND Z CHANNELS

NOTE Y AND Z CHANNELS ARE SAME AS X CHANNEL, EXCEPT Y CHANNEL CONTROLS AND INDICATORS ARE LEFT-RIGHT AND Z CHANNEL CONTROLS AND INDICATORS ARE UP-DOWN.

Figure

8-53

Incremental

Velocity 8-198

CONFIDENTIAL

Indicator

Data

Flow

-_

CONFIDENTIAL

....

PRMINI Zero

SEDR 300

Indication 8-53, three

As shown on Figure forward-aft however,

display

device.

series-connected (The same thing

since the three channels

When the display

device

+27.2 vdc signal

is then applied

the X zero indication indicates

indicates

signal

is true

are operated

for the Y an_

are identical,

only the X channel

000, all three

switches

to the X zero indication

that is supplied

that the respective

switches

counter

by

the

Z channels; is shown. )

are closed.

A

driver

develops

to the computer.

which

This signal

is at zero.

• coun,t Velocity

error

pulses

via the AFT-FWD pulses

rotary

are received

-X delta velocity are received previously

switch.

operate

of the error,

the fixed

to be driven

the same. which

and the motor 90 degrees

The motor drives

the

velocity

is not in the!center

depends

The lamp selector be lit.

lamp driver.

counter drivers

operate

for each pulse is determined

error

count

the display

position,

these

line and the the pulses

oscillator.

As

position

the lamp selector determines,

and

by means

is then supplied

Meanwhile,

drivers.

that causes

is counted.

by the relationship

the

The direction between

the sign

and the sign of the added

velocity

device

by a count

8-199 CONFIDENTIAL

to

the same pulses

to the motor

in a manner

that

counter

on the exact

Power

and supplied

pulse

position,

or the variable

that is used

lamp should

by the pulse

velocity

and

of the source of the pulses,

in which the motor is driven of the existing

selector

on the +X delta

oscillator

lamp via the associated

The pulse counter

lamp

If the switch is in the center

If the switch

Regardless

are being processed

the

from the computer

line.

counter

the selected

pulse.

to

explained 3 the oscillator

of the sign

motor

applied

from either

of the switch. the pulse

are

so that it changes

error of one

CONFIDENTIAL

for each 90 degrees of motor rotatlon.

_hus the display device maintains an

up-to-date count of the size of the veloci_

error for the assocleted axis

(in this case_ the X axis), and the direction indication lamps maintain an up-to-date Zero

indication

of _

direction

of the

error.

C_=and

The IVI counters can be individual_V driven to zero by means of set zero signals (X set zero, on Fi6ure 8-53) supplied by the discrete output logic of the computer.

The set zero signal is supplied to the set zero control circuit which

gates the 50 pps output from the fixed oscillator into the pulse counter, provided the display device counter is not already at zero.

The pulses from

the fixed oscillator then drive the motor in the normal manner until the counter is zeroed.

The pulses are applied in such a manner that the count always

decreases, regardless of the initial value.

Interfaces The IVI interfaces, which are made with the computer and the IGS Power Supply, are described under the Interfaces heading in the DIGITAL COMPUTER SYSTEM OPERATION part of this section.

8-200 CONFIDENTIAL

CONFIDENTIAL

HORIZON

SENSOR SYSTEM

TABLE OF CONTENTS TITLE

PAGE

SYSTEM DESCRIPTION ........... SENSOR HEAD ......... ELECTRONICS PACI_AGE_ ........ SYSTEM OPERATION . . • • • • • F

8-203 8-203 8-205 • • • 8-205 8-207 INFRARED OPTICS'o'I INFRARED DETECT N .......... • • • • • .... 8-211

SERVO LOOPS. HORIZON SENSOI_ I_0 W EI_ •..... • • • .

8-212 •• •• •• 8-228

SYSTEM UNITS...... . . . . , . . . 8-229 SENSOR HEAD .... , o o ° o o . o o 8-229 ELECTRONICS PACKAGE° ..... • • • 8-232

8-201 CONFIDENTIAL

CGNFIDENTIAL

PROJECT

DETAIL A

_(_i_)_

GEMINi

OFF DETAIL C

SEC DETAIL B

SEE

RIGHT SWITCH/CIRCUiT

\

BREAKER PANEL_

SEE DETAIL R

TRONIC PACKAGES

FT EQUIPMENT ' HORIZON -PRIMARY

HORIZON

Figure8-54 Horizon Sensor System 8-202 CONFIDENTIAL

SENSOR HEA0

SENSOR HEAD

IN SENSOR PAIRING

BAY

CONFIDENTIAL

PROJE

HORIZON

SYST_4

I

SENSOR

SYSTEM

DESCRIPTION

The Horizon

Sensor

System

(Figure

8-5_)

consists

of a isensor head,

an electronics

i

I package

and their associated

establish error

a spacecraft

signals

controls

attitude

proportional

horizontal

attitude.

spacecraft

or the inertial

and indicators.

reference

to earth

to the difference

Attitude

error

The system

local vertical

is used to and generates

between

signals

spacecraft attitude and a I can be u_ed to align either the

i platform

to earth

local

vertical.

The system

has a

i

null accuracy

of O.1 degree

nautical

miles.

altitude

range, measurable

spacecraft

When

attitude

and is capable

the system

errors

of operating

is operating

spacecraft

of 50 to 900

in the 50 to 550 nautical

attitude

are between

at altitudes

error

_s + 14 degrees.

i_ and 20 degrees,

the sensor

mile When

output

i becomes

non-linear

but the direction

slope of the attitude

error.

When

of its slope

always corresponds with the i attitud_ errors exceed 20 degrees,

spacecraft

i the system may lose track. The second

system

TWo complete

is provided

systems

as a backup

are _ustalled i

on the

in case of! primary

spacecraft.

system malfunction.

SENSOR HEAD The sensor head track

the

(Figure

infrared

8-55)

gradient

contains

between

equipment

earth

and

requlred

space,

_t

to scan,

the

detect

horizon.

The

and sensor

i

heads are mounted

on the left side of the spacecraft

_d

canted

I_ degrees

for-

the azl_,th

axis

!

ward

f

of the spacecraft

by a yoke assembly assembly).

Scanning

and about the elevation

Infrared

servo loop which

pitch axis.

detection

positions

is provided

the Positor

is provided

about

axis by a _sitor by a bolometer

mirror.

8-203 CONFIDENTIAL

(mlrror

positioning

and tracking

by a

CONFIDENTIAL

_

PROJECT

PYROTECHNIC

GEMINi

ELECTRICAL CONNECTOR

/

)

J5 POSITOR

_

PRE-AMPLIFIER AND POSITION I

VIEW A-A

Figure 8-55 Horizon Sensor Scanner Head 8-204 CONFIDENTIAL

DETECTOR

CONFIDENTIAL

PROJEC'T

EI_CTRONICS

vide azimuth

sensor used

head,

Electrical

levels

a_d optical

for the Positor.

the azimuth

yoke

from the constantly

error

signals

from the

direction,

Signals

from limit

to pro-

and attitude

systems.

radiation signals

required

are also

to l_m_t.

changing

Positor

during

pre-launch

are

Attitude

position

signal

is tracking.

OPERATION

initiation staging

Horizon

Sensor

radiation.

to acquire

and lock-on

system

Operation tracking horizon.

PRI-OFF-SEC

the JETT FAIR

switch,

acquisition

the horizon) lO seconds.

an_ retrograde

80 m_11 _secomds

is energized

and S_

Initial

time is approximately staging

System

of the SCAN HTR

the pilot presses

infrared

the

drive

are derived

system

The primary

plus

drive

the circuitry

to the sensor head

control

infrared

elevation

contains

signals

and platform

to constantly

the

8-56)

drive

representing

to generate

SYSTEM

(Figure

and elevation

error signals

_

package

to spacecraft

generated

when

I

PACKAGE

The electronics

signals

GEMI

section

time

switches.

exposing

Immediately

the sensor heads

(the t_me required

is approximately The system

by pilot

120

seconds;

after to

for the sensor reacqulsitlon

can be used any time between

separation.

the sensor heads

At retrograde section separation i i are automatically Jettisoned, rendering

imoperative.

of the Horizon the

infrared

Sensor

radiation

To accomplish

System

depends

gradient

the above,

on receiving, i

between

the system

earth

and

employ_

detecting space,

infrared

at

and

the

optics,

infrared

i •

detection

and three closely

of the Horizon Sensor System

related is

servo

provided

loops. in

Figure

A functional 8"-57.

CONFIDENTIAL i i

block

diagram

CONFIDENTIAL

I

PROJECT

/

GEMINI

_AUTOMATIC

RELIEF VALVE

TEST RECEPTACLE

SENSOR HEAD RECEPTACLE

Figure

8-56 Horizon

Sensor 8-206

CONFIDENTIAL

Electronic

Package

_

CONFIDENTIAL

SEDR300

I_FRAP_

OPTICS

Infrared

optics

(Figure

and an azimuth head.

8-58)

&rive yoke.

The Positor

consists

All of these

has a movable

field of view about

of a Positor,

mirror

the horizon.

components which

Radiation

a telescope-filter a#e located I

in the sensor

I

is used Ito position t

is reflected i

assembly

the system

by the Positor

mirror

I

into the telescope-filter assembly,

directs

assembly

infrared

conta$us

radiation,

microns the

of undesired (80,000

infrared

radiation

i

lens!, an infrared

The

reflected

objective

lens

by the mirrors,

The infrared

frequencies.

to 220,000

mirror,

objective

bolometer.

_,,,ersion lens of the bolometer. radiation

_n the telescope-filter i into the telescope. The telescope-filter i

meniscus

thermistor

all the _n_rared

A fixed

radiation

a germanium

a gerry+_ium-immersed direct

assembly.

filter

is used

on an immersed

and

to

on the germanium

is used to eliminate

The filter has a! band pass

angstroms).

filter

The germaniu_

immersion

of 8 to 22 lens focuses

thermistor. i

The horizon

sensor

field

of view

is deflected

throug_

160 degrees

(+_80) in

i i

azimuth

and 70 degrees

(12 up and 58 down)

in elevat_ on by rotating

the Positor

I

mirror.

The Positor

an axis which

is rotated

runs through

in azimuth

the center

by a driv

; 1

of the infrarec

yoke.

Rotation

ray bundle

is about

on the surface

! i

of the Positor circuitry

mirror.

The yoke is driven at a one dycle per second rate by +I

in the electronics

package.

The center

of ithe azimuth

scan is i_

i

degrees

forward

of the

spacecraft

pitch

axis.

This

Is due to the mounting

of

I

the

scanner

tilts

heads.

the Positor

Elevation mirror

deflection

as required

is provided

to search

iby the Positor which i for o_ track the horizon.

8-207 CONFIDENTIAL !

The

CONFIDENTIAL

j :__

I __,_-

PROJECT

SEDR 300

__r_l

GEMINI

I

r- ........

AZIMUTH

DRIVE AMPLITUDE

1

SWITCH

I J

.....O_EERS_OOT t

1

II

ROLL 8YNC SWITCH

I

--_ ,

,'

EXCITATION

J

I AZ'MUT" I

J .....

l

,=.,.....l._

I I •

( _

_

EXC'TAT'°N_*C P,ED CO,L

I

5KC EXCITATION

POSITOR DRIVE SIGNAL

_

POSITOR DRIVE)

/

I =i

_"

, ,

I

SWITCH

SWiTCN ,,, t

I

_5KC

OVERSHOOI

CLOCKWISE DRIVE

I

ROLL SYNC

AZIMUTH

.....

J I

AZIMUTH

POSiTiON PHASE

POSITION ;

POSITOR

_._"

POS,T,ON DETECTOR MIRROR I_S,TOR SIGNAL I

J

AMPLIFIER

PHASE SH,ETED POSITOR

FIELD COlt

(5KCSIGNAL FROM

THERMISTO

ASSEMBLY

PASS FILTER

I

J J

D_ FIXED

_j_

TELESCOPE-FILTER ACTIVIRoN _ 8-22 __, MICRON _IL_-BOLOMETER

M IRROR

_"

J

I

-

Figure

8-57

Horizon

PRE-AMPLIFIER

I

G ERMAN' U_v_ ER-_" MENISCUS LENS z._ THERMISTOR PASSIVE

- "-_°'_°

Sensor

RADIATION

System

Functional 8-208

CONFIDENTIAL

-

Block

- I

+28V DC SPACECRAFT POWER

Diagram

(Sheet

t

1 of 2)

J

CONFIDENTIAL SEDR 300

:-.

____"

PROJECT

GEMINI

I

I AZIMUTH CONTROL CIRCUIT

AZIMUTH DRIVE CIRCUIT

I

AZIMUTH MULTIVIBRATOR

I J

PII

PHASE PITCH DETECTOR

J

J

AZIMUTH

I f--.

SI(

FILTER AND PITCH OUTPUT AMPLIFIER

--

Z O

SYNC SIGNAL

I t_;'a_URRENT I

o

PITCH AMPLIFIER ERROR

J

J

TRACK

POSITOR POSITRON SIGNAL TRACK CHECK

CHECK CIRCUIT

_IGNAL

i

J

ROLL

o_I

ERROR

AMPLIFIER

J

SEARCH GENERATOR

_( Z O

AND

I

INTERLOCK

SIGNAL AMPLIFIER

_

PHASE DETECTOR

_

PHASE DETECTOR

DRIVE AMPLIFIER

O_]

FILTER AND AMPLIFIER

EARTH-SPACE

_

LOCK-OUT m R_ g

FREQUENCY DOUBLER

_

ROLL MULTI-

DITHER OSCILLATOR

I

_.

(30CPS) ROLL SYNC SIGNAL

E u

ELECTRONICS PACKAGE

TO SCANNER LIGHT, ACME AND IMU

/

Figure

8-57

Horizon

Sensor

System

Fur_ctional 8-209

CONFIDENTIAL

Block

Diagram

TO ACME AND

(Sheet

2 of 2)

IMU

CONFIDENTIAL SEDR300

t_!_

PROJECT

/

GEMINI

\

/

\

/

\\

/

\

i F-/ b /,

.j

F ,_t

L

-x.,

z

_

_

HOEIZON

AXIS OF ROTATION

J"_ I

" "'_ "-

AZIMUT.

(REF)

""%..%._%

i

<

t.._

ii

_

i

FO_.OE

\\, \...

t ......... "! I

POSITOR

{

I

AXIS OF

"\.

!

ROTAT,ON

:

i

MIRROR

i

I

'

FILTER

i_i::Ni::i_ >"

)LOMETER INFRARED

I

RADIATION (REF)

/

i ! i

t

I FIXED

MIRROR

_

THERMISTOR

i

!

, GERMANIUM MENISCUS LENS

Figure

8-58

Infrared 8-210

CONFIDENTIAL

LENS

Optics

THERMISTOR

CONFIDENTIAL

PROJECT GEMI, I

rate at which tion

the Positor

(track or search).

cps search rate moves

the mirror

In search mode,

plus a 30 cps dither

spacecraft

DETECTION

Infrared

radiation

The bolometer

is detected

contains

radiation

circuit.

and unbalances

an output voltage

which

If only one thermistor caused

by conduction

reference)

moves

at a two

on the direction

thermistor

l_.stor,

a given

The

ensltive

bolometer.

resistors)

which

(active) is exposed to i second thermistor (passive) is located

but it is separated

the bridge

circuit.

is proportional

f_om

used,

infrared

t_ermlstor

the bridge

which

The unbalanced

to the intensity would

to prevent

a_so

this,

radiation. changes

bridge

produces

of the infrared

radiation.

sense temperature

changes

a passive

(temperature

is used.

changes

ambient

thermistor

thermistor

resistance

temperature

is not exposed

the same amount i change,

keeping i

to infrared

as the active

the

ra_ation

bridge

ther-

balanced.

and allows

the

l

bridge

to

become

of

One of the thermistors

or convection;

The passive

The passive

(temperature

is sensed by the active

were

thermistor

for

rate depends

by the germanium-lmmezsed

from the horizon.

from the horizon

resistance

mirror

of opera-

In track imode, the Positormlrror i if there is any!attltude error, a one or

two thermistors

near the first thermistor

Radiation

of the mode

error.

are part of a bridge infrared

the Positor

The one or two cps track

attitude

INFRARED

is a function

rate.

at a 30 cps dither rate, plus,

two cps track rate.

very

tilts

unl_.lm_ced

when

the

active

ther_J.stdr

is

from the horizon.

8-211 CONFIDENTIAL

i !

struck

by

radiation

CONFIDENTIAL

PROJECT

_VO

LOOPS

The three

servo loops used

the azimuth is used

Track

with

by the Horizon

Sensor

drive loop and the signal processing

by more

than one servo loop and provides

System

are:

the track

loop,

loop.

Some of the circuitry

synchronization.

Loo_

The track loop respect

are used the

GEMINI

(Figure

8-59) is used to locate

to the elevation

in the track loop.

axis.

track mode

is located

of operation

(search

and track)

is selected

automatically

and used until

the horizon

is located.

and the signal built

is automatically

the earth horizon

The search mode

system is first energized

the horizon

Two modes

and track

up to the required

level,

when After the _.-_

selected.

Search Mode The search mode

is automatically

selected

by the system

any time

is not in the field of view.

The purpose

of the search mode

system line of sight through

its elevation

scan range until

located. positor signal

mirror. )

When the

drive amplifier. junction.

causing

is initially

which

is applied

(The dither voltages

This drive

the horizon

to a summing

to oscillate

Junction

mirror. about

is

The dither

its elevation 8-212

position a two

in the Positor to the

any time the system

to the drive

CONFIDENTIAL

produces

is also applied

are summed and amplified is applied

the Positor

The generator

signal is present

signal

it to tilt the Positor

causes the mirror

energized,

A second signal (30 cps dither)

The search and dither signal.

system

to turn on a search generator.

cps ac search voltage

drive

is to move the

(The system llne of sight is moved by changing the angle of the

is used

summing

the horizon

is energized. )

to create a Positor coils

portion

of the Fosltor

of the signal

axis at a 30 cps rate and

CONFIDENTIAL SEDR300

_-_._

PGSITOR DRIVE SIGNAL

i

5KC RIEPERENCE .___

POSITOR SIGNAL

i

PHASEI SHIFTED

POSITION PHASE DETECTOR

POSITION AMPLIF]ER

EXCITATION

]

TRACK CHECK

GENERATOR AND INTERLOCK

TRACK CHECK

EARTH SPACE

t

SEARCH

POSITOR MIRROR

LOCK'.OUT

POSITOR POSITION )AMPING

LOOP)

' F

TEUESCOPE/ I FILTER

I

FIXED

I

MIRROR

J

BOLOMETER

I

l

_r

LEVEL

PRE-AMP

AMPLIFIER

-_

PHASE DETECTOR

60CPS

DRIVE AMPLIFIER

T

30CPS

SIGNAL REFEiENCE

DOUBLER

Figure

8-59 Track

Loop Block Diagram 8-213

CONFIDENTIAL

DITHER

OSCILLATOR

CONFIDENTIAL

PROJECT

GEMINI

through an angle which represents approximately four degrees change in the line of sight.

The search portion of the signal will drive the Positor mirror

up to an angle which represents a llne of sight 12 degrees above the spacecraft azimuth plane.

During the up scan (earth to space) a lock-out signal is

applied to the servo loop to prevent the system from locking on to false horizon indications.

When the positive limit of the search voltage (12 degrees up) is

reached, the voltage changes phase and the system begins to scan from 12 degrees up to 58 degrees down.

During the down scan (space to earth), the lock-out

signal is not used and the system is free to select track mode if the horizon comes within the field of view.

The bolometer output (indication of infrared radiation) is used to determine when the horizon comes within view and to initiate the track mode of operation. As the system line of sight crosses the horizon (from space to earth), a sharp increase in infrared radiation is detected by the bolometer. bridge output now produces a 30 cps ac signal.

The bolometer

(The 30 cps is caused by the

dither signal driving the line of sight back and forth across the horizon.) The bolometer bridge output is amplified and applied to the track check circuit.

When the 30 cps signal reaches the track check circuit, it causes a

tracking relay to be energized indicating that the horizon is in the field of view.

Contacts of the relay apply a bias to the search generator, turning it

off and removing the search voltage from the Posltor drive signal. the system in the track mode of operation.

8-21. CONFIDENTIAL

Thls places

CO_:ID_NTJAL

PROJECT

GEMINI

Track Mode The bolometer output signal is used to determine the direction of the horizon from the center of the system line of sight.

A Positor drive voltage of the

proper phase is then generated to move the system line of sight until the horizon is centered in the field of view.

The bolometer output signal is

phase detected with respect to a 60 cps reference signal.

The 60 cps signal

is obtained by doubling the frequency output of the dither oscillator.

Since

both signals (30 cps dither and 60 cps reference) come from the same source, the phase relationship

should be a constant.

However, when the horizon is not

in the center of the field of view, the bolometer output is not symmetrical. The time required for one complete cycle is the same as for dither but the zero crossover is not equally spaced, in time, from the beginning and end of each cycle.

The direction the zero crossover is shifted from center depends

on whether the horizon is above or below the center of the field of view. phase detector determines

The

the direction of shift (if any) and produces dc pulses

of the appropriate polarity.

The output of the signal phase detector is applied

to the Positor drive amplifier where it is S_,mmed with the dither signal.

The

composite signal is then amplified and used to drive the Positor mirror in the direction required to place the horizon in the center of the field of view.

A pickup coil, wound on the permanent magnet portion of the Positor drive mechanism,

produces an output signal which is proportional

tude) to the position of the Positor mirror.

(in phase and ampli-

This Posltor position signal is

phase detected to determine the actual position of the mirror.

The detector

output is then amplified and used for two purposes in the track loop:

8-215 CONFIDENTIAL

to activate

CONFIDENTIAL

PROJ

EC---'T--G'EM I N I

_____

the

SEDR300

search generator

d_mp_ng

feedback

energized,

Azimuth

when

to the Positor

it biases

Drive

the tracking

the

search

drive

control

synchronization

a 160 degree

loop (Figure

required

drive

coils and an azimuth

Azimuth

Overshoot

detector,

azimuth

detector

scan overshoot.

generator.

Two iron slugs, mounted

control

drive loop

circuit,

consists

azimuth

the yoke

signal

on the azimuth

reaches

passes

multivibrator,

signal

pulse occurs

to the azimuth

control

circuit.

8-216 CONFIDENTIAL

drive yoke

pickup,

drive yoke,

reaches

located

near

pass very near

The slugs

are posi-

each end of the scan.

pickup,

to be modulated

at a two pps rate.

detect the

from the field current

the scan limit.

near the magnetic

excitation

implies,

is a magnetic

scan rate is one cps and the modulation

is applied

overshoot

llne of sight through

the azimuth

apart on the yoke to represent

one of the iron slugs the 5 kc

detects when

and excited by a 5 kc

pickup when

160 degrees

the overshoot

system

The azimuth

The detector

drive yoke

azimuth

the

does not, as the name

It instead

end of its scan limit.

and causes

is

drive yoke.

the azimuth

tioned

relay

Detector

overshoot

the magnetic

(When the tracking

the drive voltage,

to move

scan angle at a one cps rate.

azimuth

either

and as a rate

to cutoff. )

8-60) provides

overshoot

azimuth

amplifier.

generator

of an azimuth

The azimuth

is de-energized

Loop

The azimuth and

drive

relay

occurs Output

it changes with

When

the inductance

a pulse.

Since the

at each end of the scan, of the overshoot

detector

CONFIDENTIAL SEDR 300

_. r

_

I

t_!_

_'_,-

i

PROJECT

,,_._.___,_

GEMINI

_

__j_,..i

CCW AZIMUTH DRIVE AMPL[FIER

,_

CW AMPLITUDE

_dl

CONTROL

i

AZIMUTH MULTIVIBRATOR (I CPS)

AZIMUTH CONTROL

,f-_. SYNC SIGNAL

/ CLOCKWISE

DRIVE

/ AZIMUTH SYNC SWITCH

COUNTERCLOCKWISE DRIVE

/

/

:

_.

/ / / / F

/

//

__ RL°_ AMPLITUDE

OVERSHOOT _IG._L /i

SWITCH

,

/

/

Z_

_/ Figure

8-60

Azimuth

Drive

i :

Loop Block

CONFIDENTIAL

i !

_

AZIMUTH OVERSHOOT DETECTOR

Diagram

8-217

// ,KC <

EXCITATION

CONFIDENTIAL

PROJE

GEMINI

Azimuth Control Circuit The azimuth control circuit generates two types of azimuth control voltages (coarse and fine) based on the azimuth overshoot signal. shoot detector develop adc

output is rectified,

filtered, peak detected and integrated to

control voltage proportional

overshoot pulse.

The azimuth over-

to the amplitude and width of the

This control voltage serves two purposes:

to provide con-

tlnuous, fine control of the azimuth drive pulse and, when the control voltage reaches a hlgh enough level (indicating a large overshoot), provide a coarse (step) control of the reference voltage on the azimuth drive coils.

The fine

control is obtained by applying the control voltage, as a bias, to the azimuth drive amplifier.

The coarse control is obtained by energizing a relay, which

switches the reference voltage on the azimuth drive coils when the control voltage reaches a high enough level.

The level at which the relay energizes is

determined by a zener diode which breaks down and biases a relay driver into conduction.

The relay driver then energizes a relay which switches the _c

voltage on the reference winding of the azimuth drive coils.

Azimuth

Multlvibrator

The azimuth multlvibrator

provides the direction control signal for the az_,th

drive.

is synchronized

The multivlbrator

by pulses from the azimuth sync switch.

The sync switch is located next to the azimuth drive yoke and is closed each t_me the yoke passes through the center of its 160 degree scan.

The switch

produces a two pps output which is used to switch the state of the multlvlbrator.

The multivihrator

then produces a one cps square wave signal which is

8-218 CONIFIDIENTIAL

CO_Fi_DENTIAL

PROJEC Ni SEDR 300

symchronized with the motion of the azimuth drive yoke.

The positive half of

the square wave controls the azimuth drive in one direction and the negative half controls the drive in the other direction. applied to the azimuth

Azimuth

Output of the multlvibrator is

drive amplifier.

Drive Amplifier

The azimuth drive amplifier

adjusts the width

to control the azimuth drive yoke.

of multivibrator

The output pulse width, from the drive

amplifier# depends on the amount of control voltage azimuth control circuit.

output pulses

(bias) provided by the

When the amount of azimuth yoke overshoot

the control voltage is high and the output pulse width is narrow. _-_

is large, As the

amount of overshoot decreases, the control bias decreases and the output pulse width increases. and consequently

Azimuth

This provides a continuous, fine control over the drive pulse the amount of azimuth drive yoke travel.

Drive Coils

The azimuth drive coils convert drive signals into a magnetic

force.

The

coils are mounted next to, and their magnetic force exerted on, the azimuth drive yoke.

The direction of magnetic force is determined by which drive coil

is energized.

Azimuth Drive Yoke The azimuth drive yoke is a means of mechanically moving the system llne of sight through a scan angle.

(The Positor is mounted inside the azimuth drive yoke and

the rotation is around the center line of the infrared ray bundle on the Positor mirror.)

The azimuth drive yoke is spring loaded to its center position and

the mass adjusted to give it a natural frequency of one cps.

8-219 CONFIDENTIAL

Mounted on the yoke

CONFIDENTIAL

PROJECT

are two iron slugs and a permanent with

the azimuth

activate

overshoot

sync switches

mechanical

motion

the

signal

Signal

processing

Processin_

servo

(Attitude

Control

signals,

Control

command

attitude

comes within

c_ds. llm_ts, thrust

error signals.

loop is obtained and Maneuver

generated

The switches

synchronize

signals.

The function

of the azimuth

paragraph,

in the phase

thruster

The function

detectors

as indicated

by error

paragraph

is automatically

applied

System

and generate

to produce

of

attitude

spacecraft

_hen the

8-220 CONFIDENTIAL

System).

scan mode)

Attitude

to select

in the desired

the ACME

The fire direction.

direction,

spacecraft

in pitch

the

attitude

and + 5 degrees

stops generating

remains within

the error.

systems

a fire command.

If the attitude

to correct

local vertical. )

are used by the Attitude

thrust

(0 to -i0 degrees

scan in-

can be used to align

in the appropriate

in amplitude.

freely.

and azimuth

and the Propulsion

signal amplitude,

to drift

two other

Sensor

attitude,

As long as the spacecraft it is allowed

signals

(ACME) (in the horizon

System

limits

tracking

System to the earth

by utilizing

(or thrusters)

decrease

preselected

(The error

Guidance

by the Horizon

spacecraft

signals

converts

Electronics

Electronics

changes

error

be described

is used to

yoke.

multivlbrator

(Figure 8-61)

causes the Propulsion

As the thrust

roll),

loop

and Maneuver

the appropriate

will

and/or the Inertial

A complete

error

electrical

The magnet

Loo_

into attitude

the spacecraft

previously.

in conjunction

loop.

The signal processing formation

mentioned

in the azimuth

sync switches

The iron slugs are used

next to the drive

of the yoke with

sync switch was described the two roll

magnet.

detector

located

GEMINI

fire

the preselected

exceeds

in

the l_m_ts,

of

CONFIDENTIAL ...-'-_ _

SEDR 300

/

HORIZON

INFRARED RAY BUNDLE

J

_F.ARTH SYNC

/

-

(_?B

\_.___-

,AZ,MDT,I

SPACECRAFT CHANGE ATTITUDE

I

TRACK CHECK

_'

POSITION MODU LATE{} SIGNAL POSITOR

ERROR AMP LIFIER ROLL

ROLL SYNC SIGNAL

AZIMUTH SIGNAL

SYNC

ERROR AMPLIFIER

LOSS OF TRACK SIGNAL

PITCH

I

l,o.H,o,H-..,q,..i

PROPULSION SYSTEM

PHASE DETECTOR

MULTIVIBRATOR (2 CPS)

MULTIVIBRATOR (] CPS)

PHASE DETECTOR

I

XE_?_OR_ENT SIGNAL ROLL ERROR SIGNAL

FIRE

COMMAND

,_........... I

Figure

8-61

Signal

Processing

Loop

!_ C ERRORI I

..

l

;

i Block

CONFIDENTIAL i

I

LO SS-OF-I"RACK

Diagram

8-221

I

,._

._,--iTl-,

AND MANEUVER ELECTRONICS :

L

r

_

SIGNAL

CONFIDENTIAL SEDR 300

PROJEEMINI

An indirect

method

controlling

the

horizon

8 through

12)

(Inertial

Guidance).

inertial

with

of

vertical. platform method

torque

unit. gyros

The platform

in

sensor

error

fire

attitude

in all three

The inertial

platform

can also be aligned

loop.

manually sensor

attitude

horizontal

spacecraft

attitude with

are then used

to torque

platform

are then used

by the horizon a closed

fine align

the

are now used to to the local

by the ACME System.

(in the

Using

this

+ i.i degrees

sensor without

servo loop,

of

to the earth gyros

when

Attitude

and have no direct

must

(The horizon

the spacecraft

surface.)

using

the pilot

as near null as possible.

are most accurate

respect

to

them

is held to within

without

attitude

error signals

system

signals

ali_-_

6 and

axes.

To align the platform

maintain

error

platform,

the spacecraft

5,

spacecraft

for the Propulsion

the platform

a servo

spacecraft

it is desire_

attitude

signals

c_ds

(on

a third

can be used when

the inertial

attitude

control,

attitude

involves

Horizon

mode) to generate

of attitude

sensor

This method

measurement

continuously

spaceera_

is in a error

effect

signals

on spacecraft

attitude.

The Horizon AC_E

Sensor

and Inertial

or platform

degrees

also provides

Guidance

from aligning

used to illuminate the system

System

System.

The signal

to a false horizon.

the SCANNER

is not tracking.

of the horizontal

a loss of track

light

indication

is used to prevent The loss of track

on the pedestal s informing

(Spacecraft

attitude

the ACME signal

is also

the pilot

must be held within

for the system to track. )

8-222 CONFIDENTIAL

to both the

+ 20

that

....

CONFIDENTIAL SEDR 300



"_L i

AZIMUTH SCAN

4_AZIMUTH LIMIT 0°

SCAN

ii

1

SPACECRAFT ROLL

.....

--

AXIS EXTENSION

204*

AZIMUTH LIMIT 284=

SCAN

I I 270 °

AX,SEXTENS,O,.,O_ON S.SO__T_. J VIEW A-A

AHxis EXTENSION

f

-t

A

A

/ /

\

SCANNER

/ INSTANTANEOUS

x

/

LINE OF SIOHI_/

\

X i_J

\

/

;

S,'_ECRAET ','A',,' AXIS EXTENSION

\

/

)... I /_z.__

1

I/

/I //

J

II I

DITheR _

HORIZON OF EARTH

AZIMUTH fLOCA I- VER'TICAL

Figure

8-62 Horizon

Sensor 8-223

CONFIDENTIAL

Tracking

Ge[ ,merry

CONFIDENTIAL

PROJECT

GEMINI

Tracking Geometry Horizon sensor tracking geometry (Figure 8-62)

is composed of the elevation

angles (e) generated by the track loop and the azimuth angles (_) generated by the azimuth drive loop.

Angles are compared in time and phase to generate

an error signal proportional to the elevation angle change with respect to the azimuth

scan angle.

As explained in the track loop paragraph, the system will lock on in elevation and track the earth horizon.

A dither signal causes the Posltor to move

the system llne of sight about the horizon at a 30 cps rate.

The track loop

will move the Posltor mirror such that the horizon is always in the center of the dither pattern.

It was also explained, in the azimuth drive loop para-

graph, that the system line of sight is continuously moved through a 160 degree azimuth scan angle at a one cps rate.

When the spacecraft is in a horizontal attitude, the azimuth scan has no effect on the elevation angle of the Positor as it tracks the horizon.

If the space-

craft is in a pitch up attitude, the elevation angle (0) will decrease as the azimuth angle (_) approaches 80 degrees forward and increase as angle _ approaches 80 degrees aft.

If the spacecraft is in a pitch down attitude, the elevation

angle will increase as the azimuth angle approaches 80 degrees forward and decrease as the azimuth angle approaches 80 degrees aft.

This produces a one

cps pitch error signal which is superimposed on the SO eps Positor dither.

If the spacecraft has a roll right attitude, the elevation angle will increase as the azimuth angle approaches either limit and decrease as the azlm_th angle approaches zero from either llm_t.

If the spacecraft is In a roll left attitude

CONFIDENTIAL

CONFIDENTIAL

.._____

SEDR300

the elevation angle will decrease as the azimuth angle approaches either l_m_t and increase as the azimuth angle approaches zero from either limit.

This pro-

duces a two cps error signal which is superimposed on _he 30 cps Positor dither. Position Phase Detector The Positor position phase detector compares the PositOr pickoff signal with a 5 kc reference to determine the angle of the Positor mirror. will be chang_

(The mirror angle

at a 30 cps dither rate, plus, if there is any spacecraft atti-

tude error3 a one and/or two cps error signal rate.)

he phase detector output is

then amplified and applied to the track check circuit.

Track Check _

The track check circuit determines when the horizon is in the field of view. the horizon is in the field of view,

the

track

check

circuit

energizes

If

a relay.

Contacts of this relay connect the Positor position signal to the pitch and roll error amplifiers°

A second

relay

in the

track

check circuit,

energized

when the

i

system is not tracking, provides a loss of track indication to the inertial measurement unit and the ACME.

The loss of track signal is 28 volts dc obtained

through the ATT IND CNTL-LDG circuit breaker and switched by the track check circuit.

Error Amplifiers In order to obtain individual pitch and roll attitude error outputs, error signal i separation must be accomplished. fiers.

This function is performed by two error ampli-

The Positor position signal input to the error amplifiers is a composite

30 cps dither, one cps pitch error and two cps roll error signal.

The pitch error

amplifier is tuned to one cps and selects the pitch error signal only for 8-225 CONFIDENTIAL

CONFIDENTIAL

PROJECT

amplification.

The roll error amplifier is tuned to two cps and selects the roll

error signal only for amplification. their respective

GEMINI

Each amplifier

signals, producing two outputs each.

then amplifies

and inverts

The outputs are 180 degrees

out of phase and of the same frequency as their input circuits were tuned. of each error amplifier

is coupled to its respective

Output

phase detector.

Phase Detectors Phase detectors compare the phase of pitch and roll error signals with one and two cps multivibrator

reference

The multivibrators sync switches.

signals to determine the direction of attitude

are synchronized

error.

with motion of the azimuth drive yoke by three

Two sync switches, located at 57 degrees on either side of the cen-

ter position of the yoke_ synchronize the roll multivibrator with the motion of the yoke and set its frequency at two cps. passes, in either direction,

The sync switches close each time the yoke

producing four pulses for each cycle of the yoke.

Each time a pulse is produced it changes the state of the multivibrator in a two cps output.

The azimuth multivibrator

resulting

operates in the same manner except

that it only has one sync switch, located at the center of the drive yoke scan, resulting

in a one cps output frequency.

The azimuth multivibrator

a phase lock signal to the roll multivibrator ronization but correct phasing as well.

also provides

to assure not only frequency synch-

The phase detectors themselves

are act-

ually reed relays, two for each detector, which are energized alternately by their respective multivibrator

output signals.

Contacts of these relays combine the two

input signals in such a manner that two full wave rectified output signals are produced.

The polarity of these pulsating dc outputs indicates the direction and

the amplitude indicates the amount of attitude error about the horizon sensor pitch and roll axes.

Since the sensor head was mounted at a l_ degree angle with 8-226 CON FI DENTIAL

--

s_

-_

SEDR 300

400 CPS ACME POWER (FROM SCANNER

Jl

SWITCH)

1

POWER TRANSFORMER

RECTIFIER

31V DC

_. "

20V AC

30V AC

BRIDGE RECTIFIER_ FILTER

FILTER

WAVE RECTIFIER_ FILTER

J -20V

DC

FULL

+20V DC

BRIDGE RECTIFIERFILTER

:

+30V DC

-27VDC

REGULATOR

REGULATOR

_1_

-27V DC REGULATED ÷25V OC REGULATED II_ +15V OC REGULATED Ib -15VDC REGULATED IP'

_20V DC

I_

-20V DC

m +31V DC

Figure

8-63

Horizon

Sensor

Power 8-227

CONFIDENTIAL

Supply

Block

Diagram

CONFIDENTIAL

PROJEC---'T--'G-EMINI ___

$EDR300

respect to the spacecraft, the mounting error must be compensated for. rotation of the horizon sensor axes, to correspond with spacecraft

Electrical

axes, is accom-

plished by cross coupl_ng a portion of the pitch and roll error signals.

Output Amplifier

and Filter

The output amplifier-filter rectified

removes most of the two and four cps ripple from the

attitude error signals and amplifies

the signals to the required level.

The identical pitch and roll operational amplifiers,

used as output stages for the

Horizon Sensor System, are highly stable and have a low frequency response.

The

output signal amplitude is four tenths of a volt for each degree of spacecraft attitude error

The signals are supplied to the A(_E for spacecraft alignment and

to the inertial measurement

HORIZON

unit for platform ali6_ent.

SENSOR POWER

Horizon sensor power (Figure

8-6B)is obtained from the 28 volt dc spacecraft bus

and the 26 volt ac, 400 cps ACME power.

The 28 volt dc power, supplied through the

SCAN HTR switch_ is used to maintain temperature in the sensor head and as power for She SCANNER lamp.

Sensor head heaters are thermostatically

operate any time the SCAN RTR switch is on.

controlled and

The 26 volt ac, 400 cps ACME po_er is

provided by either the IGS or ACME inverter, depending on the position of the ac POWER selector.

The 26 volt ac is used to produce seven different levels of dc

voltage used in the horizon sensor.

One of the voltages (31 volts dc) is obtained

by rectifying and filtering the 26 volt ac input. obtained by transforming

The remaining six levels are

the 26 volts to the desired level, then rectifying,

tering and regulating it as required.

fil-

The minus 27 volts dc output is used to

excite one side of the bolometer bridge.

The other side of the bridge is excited

8-228 CONFIDENTIAL

CONFIDENTIAL SEDR300

i

by plus 25 volts dc.

Plus 25 volts dc is also used for transistor power in the ! The 31 volt dc unregulated output is Used as excitation for the

error amplifiers. azimuth drive yoke.

The remaining four voltages (+15, -15, +20, -20) are all used

for transistor

in

power

the

various

electronic

modules.

SYST_UNITS The Horizon Sensor System (Figure 8-54) consists of two major units and five minor units.

The minor units are:

three switches, an indicator light and a fiberglass

i fairing.

The three switches are mounted on the control ipanels for pilot actuation.

The indicator light is mounted on the pedestal and, whe_ Illuminated, loss of track. _

The fiberglass fairing is dust proof an_ designed to protect the i

sensor heads, which it covers, from accidental ground _age ing launch.

indicates a

The two major units are:

the sensor head

or thermal _mage

dur-

_nd the electronics package.

SENSOR _D The sensor head (Figure 8-55) is constructed a Positor,

a telescope-filter

assembly,

from a mag_eslum casting and contains i a signal preampZ.ifier, a position detector,

an active filter and an azimuth drive yoke. positioning mirror

assembly designed to position

The Positor (Figure 8-64)

a mlrrorabou_

is a mlrror

its elevation axis.

is polished beryllium and is pivoted on ball bearings by a magnetic i

The

drive.

The Posltor also includes a position pickoff coll for determining the angle of the Positormirror.

The telescope-filter assembly (see Figure 8-58) contains a f_xedmirror, nium meniscus lens, an infrared filter and a germanium _mersed eter.

a germa-

thermistor l_l_m-

The fixed mlrror is set at a _5 degree angle to _eflect radiatiom from the

8-z29 CONFIDENTIAL

CONFIDENTIAL

PROJECT

GEMINI

J

_

AC POSITION

COIL

_,cKoPP co,L_ POSITION PtCKOFF COIL 11hl/

ELECTRICAL CONNECTION TO R

PERMANENT MAGNET

SINGLE-AXIS

Figure

8-64

Horizon

POSITOR

Sensor 8-230

CONFIDENTIAL

Single-Axis

Positor

CONFIDENTIAL

__

SEDR300

Positor mirror into the telescope.

The germanium meniscus objective lens of the

telescope is designed to focus incoming infrared radiation on the bolometer. ;

The

infrared filter, located immediately behind the objective lens, Is designed to pass infrared radiation in the 8 to 22 micron range. bolometer

contains a culminating

directs all incoming radiation

The germanium _ersed

lens and two thermistors.

on one of the thermistors.

thermistor

The culminating

The two thermistors are

bonded to the rear of, and effectively i_,ersed in, the culminating lens. thermistors

are identical; however, one of the thermistors

the focal point of the culminating lens. to one side of the focal point.

lens

Both

(active) is located at

The other thermistor

(passive) is located

The passive thermistor is used as an ambient

temperature reference and does not react to direct infrared radiation.

Signal Preamplifier The signal preamplifier is a low noise, high gain, four stage, direct coupled transistor

amplifier.

The preamplifier

is made in modular form and potted

in

epox_ for thermal conductivity and protection from shock and vibration.

Position

Detector

The position detector is a five kc phase detector designed to determine position of the Posltor mirror.

The circuit produces a voltage which

proportional to the angle of the Positor mirror. adc

the

is

Output of the detector is

voltage which varies at the same rate as th_ Positor mirror moves.

The

detector is made in modular form and potted in epoxy for thermal conductivity and protection from shock and vibration.

8-231 CONFIDENTIAL

CONFIDENTIAL

PROJECT

GEMINI

Azimuth Drive Yoke The azimuth drive yoke provides a means of moving the Positor mirror about its azimuth axis.

The yoke is magnetically

driven and pivots on ball bearings.

The Positor is mounted inside the azimuth drive yoke and is rotated through an azimuth scan angle of 160 (+80) degrees by the yoke.

The azimuth axis of

rotation is through the center line of the infrared ray bundle on the surface of the Positor mirror.

Drive coils, located directly in front of the yoke,

supply magnetic impulses to drive the yoke.

Mounted on the edge of the yoke

(see Figure 8-60) are two iron slugs and a permanent magnet.

The iron slugs

are used to induce an overshoot signal in the azimuth overshoot detector. The permanent magnet is used to synchronously

close contacts on three sync switches,

mounted around the periphery of the yoke.

_T._,CTRC_ICS PACKAGE The electronics package (Figure 8-56) contains the circuitry necessary to control the azimuth yoke and Positor in the sensor head, as well as process attitude error signals.

The package also contains adc

five kc field current generator.

power supply and a

The solid-state circuitry is made in modular

form an_ potted in epoxy for thermal conductivity and protection from shock and vibration.

8-2_. CONFIDENTIAL

CONFIDENTIAL

RENDEZVOUS RADAR SYSTEM

TABLE OF CONTENTS TITLE

_"

PAGE

SYSTEM DESCRIPTION . . . . . . . . . SYSTEM OPERATION OIIIOeOIIO. RADAR . , . . . ........... TRANSPONDER ......... INTEGRATED OPERATION_ . o . o . COMMANDLINK OPERATION_ . . . =. . SYSTEM UNITS • i RADAR MODULATOR AND TRANSM{TTER : TRANSPONDER ANTENNA . SUFFICIENT AMPLITUDE DETECTOR i" • _ TRANSPONDER CIRCULATOR... o .... RECEIVER. , . TRANSPONDER HODUZATOR AND " =" " TRANSMITTER oeoooooo.oo RADAR RECEIVING ANTENNA SYSTEM. . GATE GENERATOR, . . . , , , • • • ELEVATION TWO-MICROSECOND MULTIVIBRATOR FUNCTIONS. . i. . DITHER BISTABLE MULTIVIBRATOR FUNCTION .eeooooe.:,,o SPIRAL ANTENNA IN ANGULAR MEASUREMENT...... . .... DITHER SWITCHES ......... RANGE AND RANGE RATE (R/R HETEiR).. RANGE SWEEP CIRCUIT ..... . . DIGITAL RANGE COUNTER ........ RADAR POWER SUPPLY...... i, • TRANSPONDER POWER SUPPLY... !...

8-233 CONFIDENTIAL

.

8-235 8-238 8-238 8-239 _ 8-239 . 8-241 : :

8"243 8-243 8-245 8-247 8-247 8-247

" . •

8-254 8"255 8-257

.

8-261 8-261

. . •

8-261 8-263 8-263 8-265 8-266 8-267 8-270

CONFIDENTIAL

PROJECT

GEMINI

RO_,C,_P I _, , RANGE/RANGE

RATE

METER

FLIGHT DIRECTOR

FLIGHT DIRECTOR

CONTROLLER'(REF)

INDICATOR I(REF)

DETAIL

A

ON _LOCK

O ON

(COMMAND IPILOT PANEL) TBY _S

RADA_ OFF DETAIL B

(PEDESTAL PANEL)

DIpOLE

(REF)

DETAILD (RIGHTWITCH/CIRCUIT BREAKERPANEL)

IREF)

DETAILC (iPILOTPANEL) REFERENCE ANTENNA

ELEVATION ANTENNA i

RDRt CMP

..... i

FLIGHT DIRECTOR INDICATOR

j

DETAIL C (REF)

ANTE_ SPfJRPAL

DETAIL D

Figure

8-65 Rendezvous 8-234 CONFIDENTIAL

Radar

System

GONFIDENTIAL SEDR 300

RENDEZVOUS

RADAR

SYSTEM

SYSTEM DESCRIPTION The Rendezvous Radar System (Figure 8-65) is incorporated in the Gemini Project to facilitate a rendezvous maneuver of the Gemini Spacecraft with the target vehicle.

The system is comprised primarily of two units, a radar located in the i

rendezvous and recovery section of the Gemini and a transponder located in the target docking adapter of the target vehicle.

The co-operative operation of the

two units enables the detection of the target vehicle by the Gemini and the determination of the range, relative velocity, and angular relationship of the two craft.

The radar transmission is also used as a carrier for the command link

intelligence; refer to the co_and

link portion of Section VIII for a description

of this system.

The Rendezvous Radar System, as described herein is applicable to the rendezvous mission of spacecraft six and those planned for spacecrafts eight through twelve. Spacecraft five utilized a rendezvous evaluation pod tO simulate the rendezvous mission.

The difference between the rendezvous mission and the rendezvous evalu-

tion mission will be discussed in the rendezvous evaluation pod portion of Section VIII.

The Rendezvous Radar System is capable of acquiring lOck-on when the target vehicle is within 180 nautical miles of the Gemini and is within 8.5 degrees of the radar boresight axis.

The angular acquisition capability increases to 25

degrees relative to the radar boresight when the range decreases to within 130 nautical miles.

The radar provides bi-level, analog, and digital outputs for

use during the catch-up and rendezvous portion of the Gemini flight (Figure 8-66). The Gemini crew is provided with visual indications of radar lock-on and Co_and

8-235 OONP'IOIENlrlAL

CONFIDENTIAL SEDR 300

,=..oJcT DIPOLE ARRAY

LOCK ( ON

R

R

AZ

ANALOGo "_

EL

OUT

, Pi2L:21 S RADAR DATA READY

_

R E NDEZVOUS RADAR INTERROGRATO8

1528 MC

RADAR TRANSPONDER

1428 MC

PRIMARY 91'_

POWER

READOUT

COMMAND R, AZ, EL_

..__j

t

PRIMARY POWER

_

_L

HOLD-OFF SIGNAL

SPIRAL

RADAR

I.

TRANSMITSA

]-USEC

2. RECEIVES THE 6-USEC AZIMUTH,AND

1528MC

PULSE ATAPRF

TRANSPONDER

ELEVATION ANGLE

TRANSPONDER

OF 250PPS.

REPLY AND

iNFORMATION

I.

EXTRACTS RANGE r FROM EACH PULSE.

3.

PROVIDES ANALOG OU'IrPUTS TO THE INDICATORS RANGEr RANGE RATE, AZiMUTH, AND ELEVATION.

4.

PROVIDES BINARY DIGITAL OUTPUTS REPRESENTING RANGE,AZIMUTH, AND ELEVATION ANGLES TO THE COMPUTER.ON COMMANO.

Figure

8-66

RECEIVES THE INTERROGATING 1528-MC I-USEC PULSES FROM THE RADAR; DELAYS 2-USEC AND TRANSMITS A 6-USEC PULSE AT A FREQUENCY OF 1428MC FOR EACH PULSE RECEIVED.

Basic

REPRESENTING

Functions

of Rendezvous

8-236 CONFIDENTIAL

Radar

System

(;ONImlDEENTIAL

PROJECT%EM, Link message acceptance.

,

Analog indications of the target vehicle range and

differential velocity are presented on the Range and Range Rate Indicator. Analog indications of the elevation and azimuth position of the target vehicle,with respect to the Gemini,are presented on the flight director indicators. indications of range, elevation, and az_,th calculating

the corrective

thrusts required

Digital

are available to the com_uter for for the rendezvous

The radar is contained within a pressurized module.

maneuver.

The module dimensions are

approximately 17 by 29 by 9 inches, the module area is l.8 cubic feet, and the weight is 72 pounds. Spacecraft

_

The radar is installed in the small end of the Gemini

on the forward face of the Rendezvous

and Recovery

Section.

The radar antenna system consists of four spiral antennas, one uncovered transmit antenna and three covered receive antennas, mounted on the radar face plate. installed

in the spacecraft, the radar is covered with the nose fairing for

thermal protection

The transponder

during the launch phase of the mission.

is contained within an unpressurized

are approximately

module.

The module dimensions

9 by 10 by 2_ inches, the module area is 1.25 cubic feet, and

the _eight is 3_ pounds. Adapter

When

The transponder

is installed in the Target Docking

of the target vehicle.

The transponder electronically

antenna system consists of one dipole and t_o spiral antennas connected by coaxial cables.

The dipole antenna

is mounted on

an extendable boom which is recessed until the extend command is given via the Digital Command System.

The spiral antennas are mounted flush with the skin of

i

the Target Docking Adapter and are mounted 180 degrees apart from each other.

8-237 CONFIDENTIAL

CONImlIDINTIAL

PROJECT

GEMINI

SEDR 300*

SYSTEM OPERATION RADAR The rendezvous

radar will,

will be covered with

the nose fairing

45 seconds the pilot will the nose fairing

During

catch up with target range

and

the initial

portion

miles

crew will

initiate

The radar

is placed

breaker, switch,

located located

to ON.

megacycles.

and twelve output

miles

After

instrument

the spacecraft w111 place

The Gemini

and closing

completing

panel

is interfaced

is allowed

six, seven,

plus

Jettisoning

will _neuver

the Gemini

to

and the

will be lagging

at a

at a rate of approximately

the catch-up

maneuver

breaker

panel,

center

console,

for warm up prior

interrogation

the Gemini

at 240 pulses

per second.

at a frequency

8-238 CONIWlOIENTIAI.

width

in spacecraft

The transmitter

Those A time

the RADAR

second for radars

those

of 1150 watts.

to STBY.

at this time.

signal has a pulse

and nine, while

circuit

to ON and the RADAR

to positioning

transmission

rate of 250 pulses per

eight,

the RADAR _

are _nergized

ON, the radar commences

The transmitted

operate

switch, thereby

in the standby mode by switching

on the main

turned

At staging

tran_mlssion.

second, a pulse repetition craft five,

orbits.

on the rig_ht switch/circuit

of 60 seconds When

phase

This mnneuver

125 nautical

radar

and the radar

radar.

circular

per m_nute.

protection.

the JETT FAIRING

vehicle.

systems with which the radar delay

the

be deenergized

for thermal

of the orbital

in co-planar,

of appro_Imatel_

1.5 nautical

depress

exposing

the target

vehicle

at the time of launch,

switch

of 1528

of i microin spaceten 2 eleven,

has a peak power

OONIFIDIENTIAL

TRANSPONDER The transponder will, at the time of launch, be deenergized dipole antenna will be retracted.

phase the transponder

is placed

and the extendable

After the target veBicle enters the orbital i

in a standby condition i and the dipole antenna

is extended via the Digital Co,_nd

System.

At this time the transponder is in

standby and is connected to the dipole antenna.

A sufficient amplitude

detector

I

is incorporated

in the transponder,

this circuit detects the initial pulses from

the interrogate radar and enables the high voltage power supply. required for the transponder

to become operational

is approximately

The period 12 interrogate

i pulses or 50 milliseconds.

When the high voltage is energized the transponder

is fully operational and will respond to the interroga;e pulses of the radar.

INTEGRATED

OPERATION

The initial pulses of the radar will energize the transponder supply.

Now energized,

the transponder

pulse repetition

frequency.

the illumination

of the LOCK ON lamp.

The rendezvous

responds to th_ radar at the interrogate

The initial reply pulses

radar determines

reply.

cause

and receipt of the reply pulse

This period of time is co_mence_ by the time zero pulse,

a pulse which occurs simultaneously mission,

From the transponder

the range to the trans x>nder by observing the

events which occur between radar transmission from the transponder.

high voltage power

with the leading edge of the radar trans-

and is terminated by the receiver video pulse!, the detected transponder The radar determines analog range by the initi stion of a ramp voltage

with the time zero pulse.

The ramp voltage continues until stopped by the

8-Z39 CONIBIOINTIAL.

CONFIDtNTIAL

PROJECT [__

leading

edge of the transponder

and the resultant are differentiated rate voltages of a voltage digital which

dc voltage

are provided divider,

occur during

reference

antenna

corresponds

provided group.

rotation,

to the flight

to indicate

and range

and are, by means

computer

clock

data is stored

position

pulses

in the shift

of the target

of the rf received

at each of the _wo angle

to nullify

the incoming

to the position used to provide shafts.

error.

required

An

needles

vehicle

antennas.

Each

difference. to achieve

this

potentlometer

intelligence,

information

of the attitude to serial binary

the latest

display and stored

to the computer.

a request

the radar data pulse,

readings

information.

which

three

are continuously

The computer

for radar information. obtains

is

is

range and angle data is stored in the shift register. of three

to

at the

induction

analog and digital

is converted

for transmission

phase

The analog angle

indicator

information

stores a series

as to indicate

pulses

The radar measures

from a zero position,

director

The Gray binary

rate meter

of 50 megacycle The digital

Succeeding

analog range

purposes.

the angular

_o each of the antenna

The radar digital register

gate.

rotate

directly

in the shift register

The radar

the phase difference

and a Gray Binary Encoder, connected

the number

to the rf received

of antenna

rate.

is peak detected

to the computer.

of the two angle antennas The amount

to the range.

for telemetry

determines

the Gemini by observing

The ramp voltage

to the range and range

the range

radar

pulse.

the range

utilized

for transmission

The rendezvous

reply

is proportional

to obtain

range by counting

register

result

GEMINI

SEDR300

complete

The radar

8-21_0 CONfflDINTIAI..

The

updated

so

sends a radar data pulse

shift register, readouts

after

receiving

and discontinues

CONFIDENTIAL

updating the information.

The radar now transmits a data ready pulse.

The com-

puter, upon detecting that the radar data is ready, transmits a series of three bursts of 500 kc pulses to shift the radar data into the computer.

The radar at

this time returns to the state of continuous data updating.

CO_4AND _

OPERATION

The radar is utilized during the rendezvous maneuver with the target vehicle as a carrier for the co.m_nd link information. system refer to the c_aand

For information concerning this

llnk portion of Section VIII.

The operation of the

radar, as a carrier, is explained herein.

The C_d

Link System, when energized, d/sables the radar pulse repetition

frequency generator and interconnects the radar and the Time Reference System. The radar now operates at a pulse repetition rate of 256 pulses per second. radar transmits data by pulse position aodulation.

The

The modulation is controlled

by a portion of the Command Dink System, the encoder.

The normal pulse repetition

time of 3900 _Icroseconds is indicative of a zero; a one is transmitted by lengthening this time to 3915.2 microseconds.

The transponder received information is provided to the sub-bit detector, a portion of the C_nd

Link System.

The sub-bit detector converts the pulse

position modulation to binary form and sends the message to the _arget vehicle progra-w,er. The proEr-ww,er verifies that an acceptable message is received and provides a message acceptance pulse to the transponder.

The message acceptance

pulse, when received by the transponder, causes the transponder transmitted pulse to lengthen from 6 to i0 microseconds and remain in this condition for three

8-241 CONFIDENTIAL

CONFIDENTIAL

PROJECT

GEMINI

i

I

256 TiMEPPS

j

TRANSMITTING SPIRAL

|

I i SY_EM 250 PPSREFERENCE ON S/C 5 THRU P rum]

I

MULTI.I

I

-

1-USEC PULSES

1150 WT , FK.

; MODUaTOR

1240PpS ONS/C to,11,_,12

TO RANGE ANALOGSTART AND INPUTS DIGITAL

_, MULTI J DELAy 2"_sEcJ

<

AZ SPIRAL

SPIRAL

SPIRAL

ELEVATION _ jv I

:>

'lt

SWITCHING ANTENNA

J'

TI

I

AZ SERVO MOTOR

:

r

I

AZ SERVO AMPLIFIER

1 ENCODER

DEMOD,

' I

'

AZGATE

_

AZ BOXCAR

J

RP

STOP

I ELSERVO I MOTOR

RCVR

I i

ENCODER

:TI

i VIDEO

--

T

L.O.

! I

DEMOD.

]

AZ INDUCTION POTENTIOMETER

I

EL SERVO AMPLIFIER

SWITCH DITHER

i

,L EL ZERO DRIVE ¥

I

REFERENCE - ! I

(

I

GEN

I

EL GATE

l

l

EL. INDUCTION POTENTIOMETER

EL BOXCAR

TARGET VERIFICATION

TO FLIGHT DIRECTOR

_

DETECTOR J AZ OFF-ZERO

SWITC H AZ PREACQ.

J AZ ZERO DRIVE

SWHC H EL PREACQ

DETECTOR EL OFF-ZERO

_ PREACQ. LOOP DISABLE

400 CPS REF.

TO R/_ METER R_ AZ_ EL TO COMPUTER

E STOP SHIFT REGISTER

DIGITAL RANGE

ANALOG RANGE

RANGE START FROM RADAR

2-USEC MULTI

TRANSPONDER

2 USEC DELAy

RECEIVER

)

ANTENNA SELECT SWITCH

. SPIRALS

I AMPLITUDE DETECTOR

I

)

l

C'RCO_TOR iTr ENABLE

Figure

MODULATOR

)

k Ill TRANSMITTER 1428 ME

8-67

Rendezvous

Radar 8-242

CONFIDENTIAL

System

Block

Diagram

>

SWITC HING

?

CONFIDENTIAL

PROJECT

GEMI

I I

tranmnissions.

The radar detects the additional pulse width and effects

the illumination of the Message Acceptance (P_qGACPT) lamp.

The previously described system operation affects onl_ the radar pulse repetition frequency.

This operation results in no alteration or inter-

ruption to the radar system.

SYSTEM UNITS RADAR MO_UIATOR AND TRANSMUTER When the RADAR switch is in the STBY position a hold Off signal is applied to i the high voltage portion of the radar power supply to iprevent it from producing ii the high voltage required by the transmitter tube.

When the pilot places the

RADAR switch to the ON position, (Figure 8-67) the hold off signal is removed, i the 1650 volts dc is produced and applied to the transmitter tube, and the radar co._ences transmitting in the search mode.

In the search mode the pulse I repetition frequency trigger multivibrator oscillates fat 250 cycles per second for radars on spacecraft five, six, seven, eight and nine, while on spacecraft ten, eleven, and twelve the trigger _Lltivibrator oscillates at 240 cycles per second, generat_-E a square wave which is used to triter

the modulator.

The mod_,latoroutput is a series of one m_crosecond positive pulses which tri_ers

the transmitter tu_e.

The tranm_tter

tube Output is a 1528 megacycle,

i microsecond_ 1150 watt pulse at a repetition rate e(_al to the output of the pulse repetition frequency trigger umltivlbrator. pulse

is

coupled

to

the

tranm_ _tting

_

spiral

to interrogate the transponder.

8-2_5 CONFIDENTIAL

Th, tranm_tter ante

_a and radiated

outlout in order

.-_

CONFIDENTIAL SEDR 300

.

,, ,__

PROJECT

/

/

/

GEMINI

/

\

X \

\

/ /

\

I

'_o

\ \

\

k \

\

/

/

ll,,//

.\

/

/

\

I / / /

\\

/

I

..//_/ !

/

x

\

/

", \\

/ I I

/

\ \ \

-;

i I

I

/ \ \ \

\

%

N

Figure

8-68

/

Transponder

Antenna

8-244 CONFIDENTIAL

/

/

/

/ /

System

Coverage

CONFIDENTIAL

PROJNI SEDR 300

TRANSPONDER

ANTENNA

The transponder

utilizes

two antenna

array and two dual spiral to the transponder located enters

the orbit phase

side of the Target the adapter

(Figure

the target

the horizontal

The

select

boom which

Adapter

(Figure

selected switch.

is retracted

of the mission.

Docking

8-68)

antenna

a dipole

system

The dipole until

The spiral antennas

and are mounted

is connected

antenna

after

antenna

array

the target are located

flush with

is

vehicle on either

the surface

of

8-65).

The dual transponder about

antennas.

by an antenna

on an extendable

systems,

antenna

vehicle.

plane.

systems

are designed

to provide

The dipole will provide

The dipole

pattern

spherical

omnidirectional

is doughnut

shaped

coverage

coverage

with

in

the dipole

i

located

in the center.

is plus

or minus 25 degrees

gain

of S.5 db.

will operate width

The

connected

In order to provide

or minus

condition

area.

The initial

amplitude mitter

operation,

strength. causes greater

radar pulses

detector.

Should

direction

has a minimum

coverage

gain of each

the spirals

The spiral beam spiral

will be with ithe internal

is 7.5 db.

circuitry

ldisconnected.

The dipole

coverage

received

The detector

turns

thereafter

it monitors

the signal

level

the transponder

spherical !

array and the spiral antennas

since this provides

The array

the dipole _attern.

and the minimum

of the transponder

in any horizontal

points.

effectively

and below

35 degrees

to the dipole

array is selected

considered

at the half power

in the space above

is plus

initial

The beam width

for the anticipated acquisition i by the transponder enables the sufficient

on the high

voltage i

required

for trans-

the received isignal to ensure

decrease

below

to switch to the opposite

strength. 8-245 CONFIDENTIAL

adequate

a s!0ecific level the detector antenna

system

in search

of

CONFIDENTIAL SEDR 300

_._-_ _

P.oJ c• o f-AND LOAD

I

J

RADARONLY

I

CIRCULATOF_

SW._ I ERGMAZ-0LANT.

I

H¥::,:_W, TCH I_ ._FRO_H_0R,OS

I

I

TRANSPONDERONLY

--J ) 1528MC TO BANDPASS FILTER

J

CIRCULATOR

J

))J

FROM XMTR, SELECT

.

_ FROM ANT.

SWITCH DRIVER

DIPOLE

FILTER

CONTROLLED ATTENUATOR

MIXER-PREAMP

OSCILLATOR

l SIG NAL DETECTOR

AMP AND DETECTOR

AMPLIFLER

VARACTOR AND SWEEP

-

VERIF, OR STOP SWEEP

I

GATE SELECTOR

AND DETECTOR

1

AMPLWtER

TGT.

I

AND GATE I-USEC

l 11 1 _i CIRCUITS

(REFERTO FIGURE 8-32)

AMP AND DETECTOR

SELECTOR

VIDEO

DELAY

T

SIGNAL

Figure

8-69 Radar/Transponder

8-246 CONFIDENTIAL

Receiver

Block

Diagram

GATE

LIMtTER

l

CONFIDENTIAL SEDR 300

PROJECT SUFFICT_T AMPLXItr_ The

signal

from

the

transponder

Ampli%m_le

Detector

(SAD).

transponder

is

stan_by_

interrogate

pulse

in

the transponder transponder decreases

below

signal

portion!of

SAD monitors

the

mode by activating

level

strength.

Should

to continually

system

pulses

mission,

when

for

the

signal

it places

the interrogate one

While

strength;

antenna

system

system

the

if it in order

signal be lost,

mtenna

the

initial

are received

the opposite

cycle from

Sufficient

th_ high voltage.

the received

it selects

the

the

antenna

When the first

the SAD monitors

circulator

(Figure

8-67) is a transmit/receive

and transmitter

provides

to the antenna

a low attenuation

and a low attenuation

The dlrectivity blocking

initial

to

the SAD

to the other

CIRCULATOR

the receiver

circulator

the

applied

re-occurs.

The transponder permits

the

During

a specific

the transponder

TRANSPC_R

is

from the radar.

is operating

until lock-on

circuit

in the transmit

to seek greater causes

Video

of the circulator

of the main

to operate

device

which

by the same antenna.

The

path for the rf from the transmitter

tube

path

from the antenna to the receiver. i provides a high attenuation and enables the

bang fr_n the receiver.

R_C_XV_R The transponder

and radar receivers

most

There are some differences,

The

respects. receiver

will he explained

input circuitry the bandpass and aut_atic

gain

to the video control

will

8-69)

first, circuits conclude

arei practically

principally

in the fo11_wing

will be discussed

filter

(Figure

way.

in the input

;The difference

then the portion output.

in

circuit. in the

of the receiver

Automatic

the discussion

8-24.7 CONFIDENTIAL

identical

frequency

of the receiver.

from

control

CONFIDENTIAL SEDR 300

PROJEEMINI Radar

Receiver

Figure

Input

8-67 shows the three receiving

the rf is connected receiving

antenna

two receiving compares

As will

system paragraph, at a time

relationships

are different. hybrid

to the receiver.

antenn-s

phase

spiral

the radar

during

while

8-69).

tor, the bandpass

filter,

The load associated

with

compares

the transponder

The signal path the voltage

compared

controlled

the radar circulator

(Refer to the discussion

attenuator

below,

its operation

load associated

with the radar hybrid

in which

in the radar

relationships Because

in phase

are combined

rf is through

attenuator

circuits in the

the circula-

and into the mixer. because

of the voltage

of the voltage

controlled

is explained. )

is explained

on

the radar

does not, the input

in both receivers switch

phese

is required

attenuator.

later

pulse.

of the combined

controlled

where

and the manner

be discussed

each return

The two rf signals being

(Figure

antennas

The

in the gate generator

discussion.

Transponder As Figure

Receiver 8-69

Input

shows, both

spirals

spiral at a time will be directed either

one will pass through

signal

is passed

controlled hybrid

attenuator

are required

was directed passed

through

toward

through

toward

the hybrid

the circulator,

to the mixer. for equal power

the radar,

the antenna

as was described

are connected

the radar,

the bandpass

select filter,

The loads associated division

switch

be received

and on to the mixer

8-248 CONFIDENTIAL

only one

switch.

on The

and the voltage-

with the transponder

in the hybrid.

for the spiral.

Since

the signal received

to the antenna

the signal would

select

to a hybrid.

If neither

spiral

on the dipole, in the same way

_

CONFIDENTIAL

PROJECT

GEMI

I

B_udpassFilters The bandpass

filters

in the transponder

the frequencies

to which

at the transmit

frequency

magacycles provide

they are tuned

are different i

of the other unit.

and the transponder

the required

and the radar iare identical;

is tuned

interference

Each

The radar

rejection

filter

is tuned

to 1528 megaclvcles. and help keep

however, is tuned

to 1428

These

filters

the transmitter

i

main

bang

out of the receiver.

Voltage-_ontrolledAttenuators

The voltagecontrolled attenuators in the radarand the transponder are identl; cal.

The purpose

holding

of the attenuator

the mixer

at far and middle power

input to a minus ranges.

is to prevent 12 _

Operation

msY4_,m.

commences

increases.

The attenuator

a _a_n

attenuation

of 2It dh.

The attenuation

automatic

gain control

The voltage-controlled the

attenuator

In the

radar,

i_pedance

input,

which is the eirovlator.

circulator

described

circulator

the sam

which

produces

mismatch

earlier, _y

varies

tends

_e

is controlled

attenuation

the

Due to the directional

it m_ters.

by a delayed

6 volts.

wave

The pa_h

mismatching.

hack

to

c_racteristic

wave will! not back

the reflected

and the

device with

by impedance

reflecti

by

is inoperative

decreases

is a! solid-state

from 0 to! minus

_o

of the m!_er

attenuator

as thei range

at the receiver

voltage

saturation

up

that thel reflected

the of the

through

the

wave takes

!

through

the circulator

_ermiuatas

wave

prevented

becoming

the

is radar

measurements

because

froa

standing

waves

in a load resistance; a standing could

wave.

upset

inaccurate.

8-249 OONWIDEIMT_I_

This

stability

thus

the reflected

precaution

is

an,_ render

the

taken angular

in

OONFIOUNTIAL

SEOn soo

The voX_e-controXled manner;

however,

effective,

attenuator standing

and the

measurements

mixer

waves is

are made in the

in the transponder are

not avoided.

pre_ented

_

functions Newer the

saturating.

transponder

the

standing

less,

Since _ves

in a s_/_r attentmtion

is

no critical produce

no

_m_avorable effects.

Automatic _reQuency Control (AFC) The automatic frequency control circuit in the transponder and radar is comprised of the local oscillator, the m_xer preamplifier, the narrow band amplifiers and detector, the amplifier limiter, the discr4m_nator _ varactor and sweep circuit (Figure 8-69).

gate, and the AFC

The varactor, a solid-state voltage-

controlled variable capacitor, is the heart of the AFC circuit.

A 0.2 cycle

per second sweep voltage is applied to the varactor when the receiver is turned on.

This voltage causes the local oscillator frequency to vary over a 1-mega-

cycle band about its operating frequency.

In the transponder, when the 1528 megacycle interrogation pulse is received, it is applied to the mixer.

Here the 1557.5 to 1558.5 megacycle output of the

local oscillator beats with it, and the 30 megacycle Intermediate Frequency (IF) is prodnced.

The IF is applied to the wide band and narrow band amplifiers.

The

signal selector gate initially selects the narrow band output since it is larger. Five pulses in 16 milliseconds produce the stop sweep pulse which ends the local osc_11-tor sweeping. crlw_-ator.

This prepares the varactor to be controlled by the dis-

The narrow band signal is amplified, limited, and discriminated.

If

the video exceeds the predetermined threshold, a I microsecond pulse is supplied which opens the discriminator gate and allows the discr_,_nator output to control

8-250 CONFIDENTIAL

CONFIDENTIAL SEDR 300

.s- _-_.

___'

PROJECT

GEMINI AFC

AZIMUTH

8ANGEL"_

//_

1 USEC

2 USEC

F

ELEVATION

2 USEC

I USEC

i

SWITCH

SWITCH

SWITCH AND STUBS

i

AND

LOAD

HYBRID

AND

RECEIVED 6 USEC PULSETIME SHARING

LOAD

FILTER

CONTROLLED ATTENUATOR

t DITHER MULTI

GATE GENERATOR

_

RANGE THRESHOLD

F

_

RECEIVER

t

AND MULTI

i /'x.

i

FROM DELAy

TOAFC VARACTOR (I USEC GATE)

SWITCH DRIVER

I USEC MULTI

2 USBC MULTI

2 USEC MULTI

H "OR" GATE

ir I I

j

-

AZ

I

RF

EL

RF

DRIVER

DRIVER

SWITCH

SWIICH

i Figure 8-70 Radar RF Switching and Return Pu kseTime Sharing 8-251 CONFIDENTIAL

J

I

CONFIDENTIAL

PROJECT

the varactor.

The dlscr_nator

it if it is high. exactly

There

increases

is no output

the frequency

from the discriminator

the 1428 megacycle

to i_58.5 megacycle 48 milliseconds the varactor

are required

gate which

Receiver

Gain gain

pulse

enables

the IF is

the discriminator

Control

pulse which

8-70)

to control

pulses

produces

in stops the

the varactor.

(AGC)

_,

a wide range

and the wide band

of input channels

are controlled

Since the signal

selector

the higher

output

to operate

at the distant

band noise feedback

the video ranges.

voltage.

band gain_ the outputs are both applied

input signals

and the decreasing

predeterm_-ed

level,

The wide band

by noise

(Figure

levels,

8-69) will

the narrow

the narrow

band

ban_

selector.

signal

noise

The AGC

As the side-_and

to the AGC

8-252 CONFIDENTIAL

input

gain than the select

circuit

band gain will be controlled

5y the signal

signal applied

automati-

8-71 shows

detector

selector

will by the

assumes

signal has also been increasing

range.

it is selecte_

gate

of the narrow band

to the AGC

The wide band

band gain.

Narrow

Figure

has 14 db higher

circuits,

When

must be adjusted

signal levels.

channel.

control.

the 1457.5 Twelve

(Figure

wide band

the narrow

it.

multivibrator

channel

nal detector

with

verification

The narrow band

of the narrow

beats

the target

and range.

control

is received,

in both the radar and the transponder

how the narrow

narrow

when

to 30 megacycles.

to acco_uodate

signals_

to produce

The I microsecond

The IF is maintained

_utcmatic

return

output from the oscillator

sweep.

discriminator

have

if it is low, decreases

30 megacycles.

In the radar, when

cally

GEMINI

control

and sig-

controls with

signal reaches

the the

selector

gate and assumes

selector

along with

the

CONFIDENTIAL

%_-

PROJECT

GEMINI

f

/

/

/

//

/ ÷o/ "_'_

1o-

/

/ I

/

/

/ / /

/

I I

o

/

/

/ ....

/

//,_/7 _

/

25-

J

40--_

'

/

_

=E

-_ I00 -

z

II/ //

%

='

//I

(

16o-

I I

\

? _z

250 --

L "%,_,..'_,,

;71

I I

, I o

RELATIVE OUTPUT SIGNAL IN DB

Figure 8-71 Receiver Operation 8-253 CONFIDENTIAL

Versus Range

CONFIDENTIAL

PRO,JECT

narrow

band noise

band noise.

detector

output

GEMINI

further

reduces

narrow

band gain

and narrow

As range continues to diminish and input signal to increase, a

greater AGO voltage is developed to hold the signal at the predetermined level. The AGC delay is overc_ne and AGC is applied to the voltage-controlled attenuator and the mixer preamplifier at near range.

AGC in these receivers is capable

of malntalnlng a constant output level with input signals weaker than -83.3 at 160 nautical miles to signals of +12 d1_nat a range of 20 feet.

MOU/LATOR AND TRAN_ The transponder

transmit_er

is

1_nk.

A hold

off

signal

is

ponder

power

supply

to

prevent

the transmitter tube.

placed

applied it

in the to

the

standby

high

mode by the

from producing

voltage the

portion high

uhf

command

of the

trans-

voltage

required

by

The initial interrogate pulses from the radar surpass

the threshold of the sufficient s_plltude detector and cause the renoval of the hold off signal.

The 15_0 volts _c is produced when the signal is removed

and the transmitter c_ences

transmitting.

In the transit

mode the inter-

rogate pulse from the radar is received at the transponder, delayed for 2 microseconds, and used to trigger the modulator.

The modulator output is a

6 microsecond positive pulse which triggers the transmitter tube.

The trans-

mitter output is a IM28 megacycle, 6 microsecond_ i150 watt pulse at the interrogate pulse repetition frequency.

The transmitter output pulse is

coupled through an rf switch to either the pair of spiral antennas or the dipole ante-_--array and radiated.

8-25_, CON

FIDENTIAL

CONFIDENTIAL

PROJECT

I_CEIV_G A_tenna

S_stem

GEMI

AI_J_NA SYST_ Description

The radar receiving antenna system consists of three dual spiral antennas 6.5

i inches in d/ameter.

The receiving antennas, along with the transmitting antenna,

form a square array spaced 0.82 wave length apart. are:

The three receiving antennas

the azimuth antenna, the elevation antenna, andlthe reference antenna.

The azimuth and elevation antennas are rotatable and @re pressurized to aid i lubrication in the space environment. They are returned to zero rotation by a preacqulsltlon loop.

The reference antenna and the itransmitting antenn- do

not rotate and are not pressurized.

The spirals are ralsed about a quarter

wave length (2-1/8 inches) above the radar face plate i and have a circumference of 2._ wave lengths (20.5 inches).

Their characteristic impedance is i

75 ohms.

The receiving antennas are operated in pair_, using the reference

ant_--a as the common element, to measure the target bearing angle. uses time sharing of the 6_nlcrosecond return pulse,

The radar

nterferometer measurement

techniques, an_ phase dither to obtain complete tracking information.

Azimuth

and Elevation

Antenna

Zeroin_

The amount that the azimuth and/or elevation antenna is rotated is the measure

of target position. When the radar is tracking a ta_eti and these antennas are following the target's changing position, lock on maylbe Inte_=_pted. When this II

happens_ it is desirable to return the antennas to zero rotation. l

A circuit

called the preacquisltion loop is provided to do this iwhen the target pulse I

is not being received.

The loop consists of the preaCquisition switch, a _00 l

cps reference voltage, output from the induction potentiemeters , a detector, the servo amplifiers, and the servo motors.

I

8-255 CONFIDENTIAL ;

CONFIDENTIAL

PROJECT

GEMINI $EDR300

The loop

compares

reference voltase.

the

output

of the

Induction

potentiometer

with

a _00 cps

If the antenna is off zero, an error voltage is produced

in the detector output. turns the servo motor.

The error voltage drives the servo amplifier which As the rotation -n_le _ecreases, so does output of

the indlctlon potentiometer; and when the potentlometer output is zero the error voltage and the rotatio_ angle are zero.

As soo_ as lock on is estab-

lished, this loop is disabled by the target verification signal.

There is a reason why the transponder transmits a 6 microsecond pulse in reply to 1-mlcrosecond interrogation pulse.

If only range data and automatic frequency

control voltages were obtained from the pulse a eimillar I microsecond pulse would _e wide enough; _,t the azimuth and elevation angle of the target must be obtained from the s_ne pulse.

The interfer_neter technique of angular measure-

ment (which will be described later) required that two antennas in the horizontel plane receive the return signal.

The signal on the two horizontal antennas

must _e present for an interval long enough to compare their phase relationship. Next 2 two antennas in the vertical plane must receive components of the return signal lo=8 enou6h to compare their phase relationship.

In this system, the

optlmum interval for the phase comparison is 2 microseconds.

For this reason

the transponder sends hack a 6-microsecond pulse.

_Ise

D1vlslon

The return pulse must be divided into 3 parts each time it is received. 8-70).

(Figure

The first part_ one microsecond, will be used for range measurement

and aut_atlc

frequency control of the local osc_11ator and receiver inter-

8-256 CONFIDENTIAL

CONFIDENTIAL

PROJECT

mediate frequency.

GEMINI

The second part will be used for azimuth angular measurement,

and the third part will be used for elevation an_arl

measurement.

The first

interval will be made i microsecond; the second and third, 2 microseconds each. These intervals add up to 5 microseconds; the remaini_

i microsecond is not

used.

GATE GENERATOR The key circuit which controls pulse divisionj switching and time sharing is the gate generator.

Figure 8-70 illustrates how the gates which perform the

required switching are generated.

To understand the iswitchingthat is done,

the gates that are generated and used, and how the return pulse time is shared, it is necessary to know the static conditions before _he pulse is returned, i the return signal path, and the sequence in which the gates and switches operate.

Static Conditions _efore Arrival of Return While

pulse

the radar is waiting for the return pulse

from _he transponder, the i

The azimuth RF switch,!the elevation RF switch,

following conditions prevail" and the hybrid switch are open.

i

The open az_--Ithand elevation switches pre!

vent rf, which arrives on these antennas, from being iconnectedto the hybrid and receiver.

Tlr_sthis rf cannot "be mt'sred with the !referenceantenna rf I

until the proper gate voltage is applied.

The open hybrid=switch keeps the I

hybrid load dlsconnec_.edfrom the hybrid.

The dlthe_ switch is closed in one Ii

of its two positions. multtvibrator)

are

Alt

one-kick

of the multlvibrators (exCept the dither bistable i multtvibrators, and in the quiescent state. They

are waiting for the return pulse to tri_er

the_ in

8- 57 CONFIDENTIAL

uccession.

CONFIDENTIAL.

PROJEC'-G-EMINI

Return

Signal

The reference

Path antenna

is the

receive the return pulse.

only

receiving

ante_ne

initially

connected

to

Following the ar_;owsfrom the reference antenna to

the input to the gate generator on Figure 8-70, the signal flow is as follows. The 6-microsecond pulse enters the reference antenna and flows through the dither switch and selected stub, the hybrid, the circulator, the bandpass filter, the voltage-controlled atenuator, and the receiver, and enters the gate generator.

Gate and Switching Sequence When the transponder pulse arrives at the antenna system, it enters the reference antenna and follows the described path to the gate generator.

Here, it is

applied as a 6-microsecond video pulse to the range threshold and multivibrator. If the pulse amplitude is large enough, the leading edge of the video pulse triggers the multivibrator.

Range

Threshold

Then the whole process of gating and switching begins.

Multivibrator

Functions

The on-period of the range threshold multivibrator is 12 microseconds.

This

threshold multivibrator has four functions : First, the leading edge of this 12 microsecond pulse terminates the range measurement in both the digital and analog range circuits.

Second, five of these pulses are integrated by the target veri-

fication circuit to produce the target verification signal.

The target verification

signal stops the AFC sweep (Figure 8-69), and disables the preacquisition loop. Third, the leading edge of the threshold multivibrator output has no effect on the dither bistable multivibrator.

The dither multivibrator

in position throughout the return pulse.

and switch remain locked

Fourth, the one-microsecond multivibrator

is triggered by the leading edge of the threshold multivibrator output.

8-258 CONFIDENTIAL.

_ONFIDENTIAL

PROJECT _@_

GEMINI

SEDR300

One-Microsecond

Multivibrator

Functions

The l-microsecond multivibrator has three functions: criminator output into the AFC varactor (Figure 8-69).

First, it gates the disThis gate permits the

output of the discriminator to continually correct the local oscillator frequency to 1458 megacycles.

Second, the 1-microsecond gate is applied to the azimuth and

elevation boxcar detectors simultaneously.

The gate dumps the charges built up

in these detectors during the preceding sampling interval.

Third, the trailing

edge of the l-microsecond gate triggers the R-microsecond multivibrator. (Figure 8-70)

Azimuth

Two-Microsecond

The R-microsecond gate. driver.

Multivibrator

Functions

pulse generated by the azimuth multivibrator

This gate performs five functions :

First it excites the azimuth rf switch

The driver closes the azimuth rf switch.

antenna to the hybrid (Figure 8-70).

is the azimuth

The switch connects the azimuth

Second, the gate enters the hybrid or

gate and excites the hybrid switch driver.

The driver closes the hybrid

The switch connects the load during the azimuth angle measurement. flattens the line and prevents ments.

standing waves from producing

switch.

This load

erratic measure-

Third, the gate permits the video received during this interval to

develop a charge voltage in the azimuth boxcar detector (Figure 8-72). charge voltage is later demodulated azimuth servo motor. is opened. the trailing

to provide

The

the control voltage for the

Fourth, when the azimuth gate ends, the azimuth rf switch

The switch disconnects the azimuth antenna (Figure 8-70). edge of the azimuth gate triggers

multivibrator.

8-259 CONFIDENTIAL

Fifth,

the elevation R-microsecond

CONFIDENTIAL SEDR 300

._ _=__

RETURN PULSE FROM TRANSPONDER ANTENNA

A

I

X

_'\\

ANTENNA

ANTENNA O

AZIMUTH

"[ I

_'_

AND ROTARY JOINT AZ RF SWITCH

I

REFERENCE

AND [

STUBS

DITHER SWITCH

H

I I

I l

DIGITAL ENCODER

i

DRIVE MOTOR

(A & B)

± 15VDC

1

RECEIVER

]

--_

L INDUCTION POTENTIOMETER

SERVO CONTROL AMPLIFIER

VIDEO GATE AND BOX CAR DETECTOR

REGISTER

_\

DRIVE AND ± REF. GEN.

ULAIOB

//

F

ELEVATION

" IA + B

\ iiii

0 I_ L_

,.._"GET

RANGE

OFF BORESIGHT

Ist

I

I +B

,

I

PULSE

-R

I

!

ALTERNATE PULSE

TARGET ON BORESIGHT

I.)

DETECTOR OUTPUT

2.)

Figure

8-72

RECEIVER6 USEC PULSE TIME SHARING

Interferometer

Measurement 8-260

CONFIDENTIAL

3.)

of Target

Angle

OUTPUT OF HYBRID WITH DITHER (TARGET ON BORESIGHT)

CONIFIOtNTIAL

PROJECT _.

GEMINI

SEDR300

ELEVATION TWO-MICROSECOND _LTIVIBRATOR

The

FUNCTIONS

output of the multivibrator is the elevation gate i

functions: hybrid.

It performs five

First, it keeps the hybrid switch closed and the load applied to the

Second, it closes the elevation rf switch and connects the elevation

antenna to the hybrid.

Third, it permits the video received during this interval

to charge the elevation boxcar detector.

This voltage charge is later demodulated

to become the control voltage for the elevation servo motor.

Fourth, the end of

the azimuth gate opens the elevation rf switch and disconnects the elevation antenna.

Fifth, the end of the gate also ends the drive to the hybrid switch

and disconnects

the hybrid load.

DIT_I_ BISTABLE MULT_TOR

FUNCTION

The dither bistable multivibrator has one function: the double-pole double-throw dither switch.

to change the position of

The dither multivibrator is insensi-

tive to the leading edge of the 12-microsecond threshold multivibrator pulse. However, the trailing edge of this pulse will trigger lthe dither multivibrator. Hence, the dither switch and stub are changed 6 m_croSeconds after every return pulse ends.

SPIRAL _

IN AN_

Interferometer'Meas_ement

MEASUREMENT of Am_ar

Displacement

The method of measuring angular displacement employed fin the Rendezvous Radar System uses rf waves from a point source, the operating transponder antenna (Figure 8-72).

These waves are received simultaneously by two of the three

spiral receiving antennas of the Rendezvous Radar.

The length of the rf path

to the reference antenna is compared first with the length to the azimuth antenna, then with the length to the elevation antenna. 8-261

CONFiDENT'A"

The transmission

lines

CONFIDINTIAI-

from the three receiv4_n_antennas are wired so that rf voltage induced in the azimuth and elevation antennas will be 180 degrees out of phase with rf voltage induced in the reference antenua, if the transponder is on the radar boresight axis.

The sum of two co_ared

voltages will be zero.

If, however, the trans-

ponder is off the boresight axis, in azimuth for instance, the path lengths to the reference antenna and to the azimuth antenna will be different.

There-

fore, the phase difference between the RF voltage induced in the two antennas will not be 180 degrees. (or a n11_I) as before.

As a result, there will not be complete cancellation

A voltage proportional to the displacement from the

boresight axis will result.

_Iral

Rotation

This voltage is called the error voltage.

_ulls _rror Volts_e

The method used to _111 out the error volta@e constitutes the interferometer method of angular measur_nent. spiral antenna.

This method depends upon a pe_,3_arlty of the

The spiral antenna shifts the phase of the rf voltage induced

in it as it is rotated about its center.

Therefore, the 180-degree phase

difference hetweeu the azimuth and reference antennas can be obtained by rotating the az_--,thantenna. the n,,11is pr_lo_Ll

The amount of azimuth anten-a rotation required to get to the target displacelent in a_th.

If the error

voltage is used to drive a motor which rotates the azimuth antenna, then when the null is reached, the error voltage is zero, and the motor stops rotating. The antenna also stops rotating.

If a sens_n5 device is put on the azimuth

antenna which counts the -_-ular rollsof rotation or generates a voltage proportional to the rotation, a digital or analog measure of the target's angular displacement in azimuth from boreslght is provided. is what Is done.

Figure 8-72 shows that this

Displacement in elevation is measured in a s_m_lar manner.

8-Z6_

CONFIDENTIAL.

PROJECT

QEMII

SEDR 300

i

DTq'm_ _r_ Interferometer ferometer

measurement

measurement

not _n which

tells how much

direction.

and

two

are

installed

hybrid.

the

ponder

pulses

transponder changed.

of

of

the

are received

diode

the dither

position

dither

on the pilot's

switches,

dither

the is

Inter-

axis but

is added.

the long

or above

these

can detect

target

antenna

stub.

of three

the

Signals signals signal

short

Successive

of the dither

left

switches switches

and the

switches.

stub trans-

After

switches

or from below the short

the boresight

a relnforced

diode

The diode

with

stub, weskenedlby

polarized; with

stubs.

r,:ference

positions

stub.

throw

assoc:_ted

with

by the long

is associated

callq:d

on the pilot's

right

double

the positions

by the long

stubs but oppositely position

dlrecti_m,

between

switches

received,

by the short stub, weakened

target

line

from the target

sight axis are reinforced

on both

data.

is o: :f the boresight

line,

in alternate

pulse has been

from the target

target

transmission

line, the other

Signals

direction

I

two sln@le-pole,

transmission

One position

of transmission f-

contains

lengths in

does not yield

the target

To establish

circuit

different

angle

Direction

DitherSensesAn_r The phase dither

of target

each

are

the bore-

stub.

Signals

axis are reinforced

along average

the axis are equal out to zero.

in a given

Since

position

of

directions.

O

• During

the catch-up

phase,

equal to or less than feet. range

This means,

the closing

the square

for instance,

range

rate ini feet per second may be

root of the numerical that at

rate is 547 feet per second;

value

of the range

300,000 feet, the maximum

at 30,000

8-263 CONFIDENTIAL.

feet,

173.2

in

closing

feet per second;

but

CONFIDENTIAL SEDR 300

_-._'_

_

PROJECT

GEMINI

30V -

2or-

10V -

3,000 FT 6.1 USEC

1/

30,000 FT 6,[ USEC

300,000 FT 61OUSEC

RANGE IN FEET RANGE SWEEP TiME IN MICROSECONDS

Figure

8-73

Range/Range

Rate

Meter

8-264 CONFIDENTIAL

and

Operating

Curve

CONPlDENTIAL

PROJECTSEDR 300GEMINI

__

at 3,000 feet, 51;.7feet per second is maximum.

The range and range rate

scales are arranged concentrically on the R/_ meter so that the range is on a radius directly adjacent to the maximum closing rate.

!Figure 8-73) Hence, as I !

jtoward zero, the closing long as the range rate needle precedes the range needle i I rate is not excessive.

When the indicatln5 edges of the= needles coincide as the i needles move toward zero, the maximum tolerable clos_n5 irate is ind/cated. If the range needle precc_lesthe range rate needle toward

ero_ the clos_n_ rate

Is excessively high.

Vernier range rate is indicated in one foot-per-second increments from plus 5 to minus 5 feet per second on the scale located above center on the R_

meter.

The indicating needle for the vernier meter is usually _ff scale and out of sight until the spacecraft is within very near range of the target.

RANGE SW_m

CIRCUIT

Compression

and _xpansion of Meter Scales

The range and range rate meter scales are clearly nonlinear. are compressed, minimum values are expanded.

Maximum values

This is done because precision J J

indications of range and range rate become far more critical as the range to target closes.

Ra_e

Sweep Expansion and Compression

In order to ma_.e a current-operated meter indicate the irange and range rate with high accuracy, a special range sweep circuit is used (Figure 8-73)• The i rate of voltage change with time d_ring the first 6.1 microseconds of sweep is the most rapid.

Thus the range indication from 0 to 3;000 feet is the most

8-_5 OONF|DEN'riAL

....

j

_

CONFIDENTIAL

PROJECMINI __

SEDR300

expanded.

During the next .54.9microseconds of the sweep, the volta6e increased

with time at about i/gth the rate of the first 6.0 microseconds.

The range

indication from 3,000 to 30,000 feet is expanded to a reduced extent. the last _9

During

microseconds of the sweep, the voltage increases at 1/90th the

rate of the first 6.1 microseconds.

The range between 30,000 and 300,000 feet

is compressed into a small portion of the scale.

Thus the near range is 9 times

more sensitive than the middle range and 90 times more sensitive than the far range.

Range Measurement Range is measured by sampling the sweep voltage at a time coincident with the leading edge of the transponder return pulse. into adc

The sampled voltage is stretched

voltage, and applied to the range meter winding.

Range Rate Measurement R_ge

rate is a function of the difference in range voltages on successive

transponder pulses.

This voltage difference is monitored, shaped and amplified

in a circuit controlled by the same logic that changes the range sweep slope. It is applied as a dc voltage to the range rate meter coil on the far and intermediate ranges, and to the vernier range rate meter coil on the near range.

DIGITAL RANGE COUNT__ _R

Range Gated Clock Pulse Count A high-speed digital counter counts lO-megacycle clock pulses during the range gate to generate the digital range count.

(Figure 8-67 and 8-69).

The clock

pulses are produced by a I0 megacycle crystal-controlled oscillator in the

8-265 CONFIDENTIAL

CONIFIDI[NTIAL SEDR300

PROJECT GEMINI spacecraft edge

radar.

of

the

a s_m_lar leading

The

range

interrogating

edge of the transponder

range supplied

(whichever

equals

delay

The range

Oo I microsecond

to the computer

is larger)

the

leading

compensates

gate is closed

for by the

Power Requirement

Primary

power

source.

to operate

Voltage

and transients

available

Filtering

operated

power v_Its_e

Input Filter Unregulated

Accuracies

are obtained

within

of radar

range.

of four

successive

50 feet

or O.l percent

for ranges

radar

digital

up to 250 nautical

is obtained

source may vary between

by various

spacecraft

of the primary

equipment

from the source.

is reduced

is the average

the rendezvous

from this

produced

in this power.

Electrically

or 50 feet

of

miles

SUPPLY

primar_

filter

2-microsecond

after

pulse.

of the range to the target.

RADAR POWER

primary

This

2 microseconds

of Range to Clock Time

the range

_

started

the transponder,

One cycle at lO megacycles

counts

is

pulse.

delay through

Relation

Digital

gate

at a high

requires

and constant

30 volts

de,

Noise

will also be present

is essential.

in the spacecraft

The radar

22 and

equipment

power

from the spacecraft

wil_ reduce

a means

level_

the voltage

of maintaining

eVen though

its

source voltage

considerably.

and Boost Regulator primary

removes

power

is applied

to the radar

the noise and transients.

A boost

8-267 CONFIOINTIAI.

p_r

supply

regulator

input.

An input

uses a portion

of

CONFIDENTIAL SEDR 300

-_

136.5 VAC >

RECTIFIER

RADAR

>

REGULATOR

> +I20VDC

REGULATOR

_

AT 8 MA

F_ER

PRIMARY POWER 22 to 30VDC

-40VDC RECTIFIER

45. BVAC

(UNiEO)

J

]

-40VDC AT 75 MA

FILTER ) _40VDC AT 80 MA

REACTOR

RECTIFIER FILTER

REGULATOR

FILTER

BOOST REGULATOR

D_ - AC INVERT•

RECTIFIER FILTER

REGULATOR

), +20VDC AT 184 MA

RECTIFIER _6.3VDC FILTER

REGULATOR

) ¢6.3VDC

AF 1093 MA

> -6.3VDC

AT 1137 MA

30.4VAC

PROM CONTROL

--

LIMITER AND SWITCH TRANSISTORS

PANEL

TRANSFORMER

l

3_.vAc

_,

-6,3VDC H.V. INVERTER

H.V. ;('FORMER

24.9VAC "

RECTIFIER FILTER

REGULATOR

RECTIFIER FILTER

REGULATOR

RECTIFIER DOUBLER

'

_ -20VDC

b' +ISVDC

FILTER

16VAC

RECTIFIER FILTER -15VDC

t

_

AT 237 MA

360 MA FOR EACH VOLTAGE SEPARATELY BUT NOT

-15V

I

SIMULTANEOUSLY _' +1650VDC AT 0.5 MA

136,5VAC

)

RECTIFIER

REGULATOR

_ +12OVDC AT 8 MA

RECTIFIER FILTER

REGULATOR

_ -40VDC

RECTIFIER FILTER

REGULATOR

)

RECTIFIER

REGULATOR

TRANSPONDER

FILTER

SATURABLE REACTOR

45. 7VAC"

_NVERT. DC-AC

• :kl% l

BOOST

) Aj

j

POWER

, I J

24.9VAC

I

_.

J

h

FILTER

_.3 J RECPIE,ER F'LPER

HOLD-OFF SIGNAL FROM S.A, D, AND

)

AND SWITCH TRANSISTORS

ENABLE CIRCUIT

DOUBLER

_

/_

I NVERTER

8-74 Radar

and

I

)-20VDC

REGU_TOR

12.6VAC_

Pigure

+20VDC AT 106 MA

24.7VAC

9.2,vAc 2" VOC UNREG

AT 40

>_.3VOC A,_206 _

I

) _1200VDC AT3MA

X'FORMER

Transponder 8-268

CONFIDENTIAL

Power

Supply

Block

AT227MA

Diagrams

CONFIDENTIAL

PROJECT ___

GEMINI

SEDR300

the filtered pri_a_y

primary

voltage.

power

to generate

The voltage

a voltage

generated

31.7 volts dc (the boost regulator

:

depends

output)

to add in series with on the difference

and the primary

the

between

voltage.

The boost

i

regulator

generates

1.7 volts

dc and adds

it in series when

the pr/m_ry

voltage

i

is 30 volts dc.

As the primary

voltage

decreases,

the boost

regulator

output

i

increases

DC-to-AC

_--_

by an equal amount

(Figure

8-7_).

Inverter

The dc to ac inverter

changes

The saturable

which is connected

reactor

output.

The inverter

windings

provide

output

voltages

energizes

are rectified

outputs

each regulator.

are

which

high

enough

higher

voltage

voltages

from the power

these,

The remaining

of the plus

120 volts

20 volts

The plus and minus

to operate

requires.

Two of

their

ac.

stabilizes

the

secondary

Nine

6.3 volts

of the ac

the plus

seven

circuit

and minus

rectified

and

is built

into

dc, the plus

dc are each operated

regulators.

transformer

31 volts

Multiple

A short-circuit-proof

The regulators

they regulate.

the inverter

the radar

regulation.

regulated.

dc into

transformer.

and filtered.

40 volts dc, and the plus and minus voltages

31.7 volts

across

the power

all the voltages

15 volts dc, are used without filtered

the regulated

and minus by the

dc do not provide

Therefore,

are provided

a

additional

to operate

these

regulators.

High Voltage

Power

The transmitter llSO-watt

requires

pee2power

of generating

Supply plus

1650 volts

interrogator

this voltage

pulse.

is therefore

dc plate

voltage to produce the ! A high-voltage power supply capable

provided.

8-269 CONFIDENTIAL

Although

another

winding

CONFIDENTIAL

PROJ

could

EC-T GEMINI

have been added to the power transformer

needed,

transients

would be applied

transmitter was fired.

the high

common transformer

ac voltage

each time

the

Consequently, a separate de to ac inverter and high-

voltage transformer were used. high-voltage

to the

to supply

Only a 6.B volt ac switch voltage for the

inverter was taken from the common transformer.

In the standby

state, the regulated 31.7 volts dc is applied to the high-voltage inverter. The s_-Itchingvoltage is applied through the current limiters to the highvoltage inverter, but is grounded out by the switching transistors which are conducting.

The holdoff signal applied by the RADAR switch in the STBY

position to the switching transistors causes them to conduct, preventing the high-voltage inverters from operating.

When the pilot puts the radar in the

search mode, he places the RADAR switch to ON.

This action removes the hold

off voltage, and permits the 6.3 volts ac to switch the inverter on and off. As the inverter is switched, the ac voltage is generated and applied to the hlgh-voltage transformer. it to a voltage doubler.

The transformer steps up this voltage and applies The voltage doubler rectifies and doubles the ac

output of the transformer, and delivers plus 1650 volts dc to the transmitter tube plate.

TRANSPONDER

No high-voltage regulation is required.

POWER SUPPLY

Power Supply Similarities By comparing the block diagrams (Figure 8-74) of the radar and transponder power supplies, the similarities will be apparent. boost regulator, adc

Both power supplies use a

to ac inverter, a power transformer, rectifier, filters,

and regulators to provide plus 120, minus _0, plus and minus 20, and plus 6.3

8-270 CONFIDENTIAL

....

CONFiOENTIAL

volt dc outputs.

The same high-voltage circuitry is also used.

T n-pcnder P er SuppiV Di Terences Certain differences, of course, between the two power supplies do exist. i

The

i

following are the differences: minus

on

6.3, and plus

individual

and

supplies

minus

differ

The transponder doe_ not require the plus _0, I_

volt

owing

to

dc power

the

suppiles.

peculiar

ineeds i

The

of

cu/Tent

the

two

drains

units.

The transponder high-voltage power supply is turned ionwhen the sufficient amplitude detector triggers the enable delay circui_ and removes the hold off voltage. solid-state

Less

transmitter

antenna

select

power switch

is

used

in

(Figure

the

8-69).

f_

8-z71/ 2 CONFIDRNTIAL

transponder

to protect

the

COMMAND

LINK SYSTEM

TABLE OF CONTENTS TITLE

PAGE

SYSTEM DESCRIPTION .... SYSTEM OPERATION eeeeoeooeooe SYSTEM UNITS ..... SUB BIT DETECTOR COMMAND LINK ENCODER

. . . 8-275 8 " 281 • • • • • • 8-283 • • •. • • • 8-283 : . . . :.... 8-287

8-273 CONPIDRNTIAL

. . .

.

CONFIDENTIAL

ENCODER CIRCUIT

_ENCODER

CONTROLLER

Figure

_'_RIGHT

8-75

Command 8-274

CONFIDENTIAL

Link

System

SWITCH AND.CIRCUIT BREAKER PANEL (REF)

CONF|DENTIAL

PROJECT _@

GEMINI SEDR300

CO_AND

SYSTEM

DESCRIPTION

The Cow,hand Link craft link

to allow control

or off,

System

hardline

is used as a means of positioning

the target

vehicle

in the de-

monitoring.

path,

after

8-3.

Prior

to docking

radar

aboard

by the pilot,

the radar

docking,

messages

the command

of the

•target

vehicle

progrsn_f_er.

After

docking,

the command

rf transmission

Commands

onto the radar The desired

controller,

panel.

radar

_e

transmission

link messages

by which

method

the pilot

unchanged.

The

cof._and li'_k olso provides

inserts

8-275 CONFIDENTIAL.

are listed

located

message

and

with

in

is inserted,

slightly

the transponder

through

in

the rendezvous

aft of the by pulse to the

the hardline

the desired

the pilot

at the completion

allocated

is then transmitted

through

and a

of transmitting

transponder

below

on

required

to docking

presently

command

are routed

_e

_ehicle

located message

w.ubilical.

from the target

prior

link is capable

8-76).

lights

Systems

for each of the comnmnds

vehicle.

into the encoder

modulation

number

and approach

and Instrumentation

command

is locked

breaker

acquisition

lir_ may be used any time that

of the target

right switch/circuit

the

(Figure

three digit

the spacecraft

adapter

of turning

Communications

Using

128 command

Table

_11atch

Space-

Command

and a corresponding

position

into the Gemini vehicle.

and orbital

pilot

is incorporated

the target

t_bilical

a possible

8-75)

to control

and for controlling

for ground

docking

(Figure

the spacecraft

sired attitude

_

LII_K SYSTEM

the

message

remains

cap8bility

of the mission.

to

CONFIDENTIAL

._T-.._ _

SEDR 300

__


_8 ON i_'8

'

J



-_

T

_ E o2_ NZ_ Z_U

ds_

,

NZ

_

a

OO_ _

z

_ Zo

_--"

0

Z

91

i

Figure

8-76

Command

Link

8-276 CONFIDENTIAL

System

Block

Diagram

N_ _ Z

CONFIDIINTIAL

PINI ._

m

SEDR300

,

TABLE 8-3 COMMAND FUNCTION LIST AGENA TARGET VEHICLE SPACECRAFT COMMAND _R

REAL TI}_ CO_D

CO_ND

T_

001

0_i

C-Band Beacon

010

_010

S-Band Beacon On

011

0000011

Modulation Bus SelelctNormal i i i

020

0000100

Modulation Bus SelelctReverse

021

0000101

Telemetry On

030

0000110

TelemetryOff

031

O000111

Stored Data Readout

041

0001001

Record Data

050

O001010

C and S-Band Beacons Off

060

0001100

Reset Timer Reset

061

0001101

Time Word Reset

070

O001110

L-BandBeaconOff

071

O001111

L-Band Beacon On

140

_ii_0

Approach Lights Of_i

141

0011001

Approach Lights On_

151

OOllOll

160

0OlllO0

Extend Boom Antenna i Antenna Transfer, _scent

161

OOlllOl

Antenna Transfer, Orbit

200

01_

201

01_i

Agena Status Display Off i Agena Status _sp_ i On Bright

211

01_iI

Agena Status _sp_

i

8-_ CONFIDENTIAL.

On Dim

CONFIDENTIAL

PROJECT _.

GEMINI

SEDR300

TAm 8-3 (Continued) CO_a4AND FUNCTION LIST AGENA TARGET VEHICLE SPACECRAFT CO_4A_D NUMBER

REAL TD_ CO_

CO_AND

TITLE

220

0100100

Adapter

Unrigidize

221

OIOO101

Adapter

Ridlgize

240

0101000

Stored

Program

Commands

Disable

241

0101001

Stored

Program

Co_nds

Enable

250

0101010

Acquisition

Lights

Off

251

OlOlOll

Acquisition

Lights

On

260

0101100

Dipole

Select

270

0101110

Spiral

Select

271

0101111

Power Relay Reset

300

OllOOOO

Horizon

Sensor

Off

._01

0110001

Horizon

Sensor

On

310

0110010

Roll Horizon Sensor to Yaw, Inertial Reference Package On

311

0110011

Pitch Horizon Sensor to Yaw 3 Inertial Reference Package On

320

0110100

Horizon

Sensor

to Yaw Out of Phase

321

0110101

Horizon

Sensor

to Yaw in Phase

340

0111000

Velocity

341

0111001

Gyrocompass ing On

350

0111010

Geocentric

Rate Off

351

0111011

Geocentric

Pate On

Meter

8-t 8 CONFIDENTIAL

Interrogate

CONFIDENTIAL

SEDIt 300

TABLE 8-3 (Continued) C0_4AND FUNCTION LIST AGENA TARGET VEHICLE SPACECRAFT COMMAND NU_.R

REAL COMMAND

COMMAND TITLE

360

0111100

Geocentric Rate Reverse

361

0111101

Geocentric Rate Normal

370

0111110

Attitude Control S "stem Pressure Low

371

0111111

Attitude Control S "stem Pressure High

400

i000000

Attitude Control S 'stem Off

4Ol

lOO0001

Attitude Control S 'stem On

410

i000010

Pitch/Yaw Minus

411

i000011

Pitch/Yaw Plus

420

i000100

Pitch/Yaw Low Rate

421

I000101

Pitch/Yaw High Rate

4_0

iO00110

Pitch Rate Off

431

i000111

Pitch Rate On

440

I001000

Yaw Off

b2_l

i001001

Yaw On

450

I001010

Attitude Control System I_adband Narrow

451

i001011

Attitude Control S "stem Deadband Wide

460

iO01100

Attitude Control S 'stemGain Low

470

i001110

Attitude Control S "stemGain High - Undocked

471

i001111

Attitude Control S "stem Gain High - Docked

8-279 CONI:IOINTIAL.

CONFIDENTIAL

D TA_E 8-3 (Continued) C0_M_D AGE_A SPACECRAFT C0_D NUMHER

FUNCTICB LIST TARGET VEHICLE

REAL TIME C0_AND

COMMAND

TITLE

_00

i010000

Primary

Propulsion

System

Cutoff

501

i010001

Primary

Propulsion

System

Start

520

1010100

Velocity

Meter

Disable

521

i010101

Velocity

Meter

Enable

530

10lOll0

Velocity

Meter

Load

531

1010111

Velocity

Meter

Load l

540

1011000

Velocity

Meter

to Mode

IV Off

541

I011001

Velocity

Meter

to Mode

IV On

550

1011010

Secondary

Propulsion

System

551

i011011

Secondary Initiate

Propulsion

System

16 Thrust

560

lOlllO0

Secondary Initiate

Propulsion

System

200 Thrust

561

i011101

Secondary

Propulsion

System

570

1011110

Hydraulics

Gain

- Undocked

571

i011111

Hydraulics

Gain

- Docked

8-280 CONFIDENTIAL

0

Thrust

Ready

Cutoff

CONFIDENTIAL

,EOOO .

PROJECT ._-_

SYSTEM

GEMI

i

I

OPERATION

The C_and

Link System is energized by placing the ENCDR circuit breaker in

the ON position.

The ENCDR circuit breaker is locatedlon the right switch/

circuit breaker panel.

The cu_,and link may now be used for the transmission

of messages.

To initiate a c_nd

the Gemini pilot selects a co_and

Inserts the corresponding

from a list provided.

three digit number into the encoder

controller.

i

For example; Target Docking Adapter Acquisition LightsiOn command number is 251°

To transmit this message the Gemini pilot adjusts the encoder controller

to the following positions:

the outer octal dial is turned to 2, the inner

octal dial is turned to 5, and the binary switch (XMIT_ is positioned to I and held until the message effect of the co_and

cycle described in this sectionlis completed. link message transmission

changing of the radar pulse repetition

The only

on the! rendezvous radar is the

frequency.

During the message trans-

mission the radar is switched from the internal generated pulse to the more stable Time Reference

System generated

256 pulses per Second.

The encoder controller output is a seven binary digit (bit) binary word, three blnarybits XMIT switch.

indicating

each octal number and one blnarybit

The co_and

two binaryblts,

corresponding

to the

message is added to the vehicle address, consisting of

and the system address, consisting ofithree binary blts.

The

vehicle address used is the two binary numbers I l, the system address is i O i. It is therefore seen that the complete c_nd

8-281 CONFIDENTIAL

function word is as follows:

CONFIDENTIAL

PROJECT

GEMINI

VEHICLE ADDRESS

SYSTEM ADDRESS

2

ii

101

010

CO_@L_ND 5

i

010

1

The positioning of the _MIT switch to either the I or the 0 position also initiates a one time transmission

of the command.

The command llnk data transmission is accomplished in the following manner.

The

Time Reference System provides two trigger pulses to the encoder, both having a repetition rate of 256 pulses per second.

One pulse will be referred to as

occurring at Time Zero (To) and the other at time zero plus 15.2 microseconds (TO + 15.2).

At the time the ENCDR ON circuit breaker is turned ON the radar

commences being pulsed by the TO pulse from the Time Reference System. transmit co_ud,

The

initiated by the XMIT switch, causes the information bit to be

taken, one at a time commencing with the vehicle address, and further encoded into five binary sub-bits.

The encoder affects pulse position modulation

of the

radar interrogate transmission by allowing the TO or TO + 15.2 pulse to trigger the radar, indicating a 0 or a 1 respectively.

The interrogate transmission, at the repetition rate of 256 pulses per second, is received at the radar transponder. applied to the sub-blt detector.

The transponder

The sub-bit detector

receiver video signal is contains an oscillator

which is synchronized with the received interrogate 0 pulse.

The oscillator

provides two gates, one which occurs in synchronism wlth the TO pulse and another with the TO + 15.2 pulse.

The coincidence of the received pulse with one of the

above gates results in the identification of the pulse modulation.

A decoded 0

generates a 25 microsecond pulse across the message complement output and a

8 -282 CONFIDENTIAL

CONFIDENTIAL

PROJI

___ decoded pulses

I generates are provided

SEDR300

a 25 microsecond

pulse

across

the message

output.

These

to the progra_m_er.

The programmer

converts

the 60 sub-bits

back

The programmer

verifies

that the sub-bit

into the 12 information

code is correct,

bits.

that the vehicle

and

;

system

address

aforementioned tance

pulse

is correct,

message was received. If the i are met the progr_a,erwill provide a message accep-

requirements

to the transponder.

consecutive

transmissions

microsecond

pulse

width

pulse width and causes encoder

and that an acceptable

controller

The message

from the transponder to ten microseconds.

the Message

to illuminate

Accept

of the MSG ACPT light

message

received

the

XMIT

SYSTDi SUB-BIT

three

light,

located

on the

to the pilot

At this time

that an acceptable

the pilot may release

switch.

UNITS DETECTOR

The purpose

of the sub-bit

transmitted

pulse modulation

bit code. message

causes

of 2.5 seconds.

indicates

by the progrs_er.

pulse

to shif_ from the normal six i The radar detects the additional

(MSG ACPT)

for a period

The illumination has been

acceptance

The sub-bit

acceptance

Prior to lock-up standby frequency

detector

to a pulse

detector

pulse

Link

state by the incorporation driven

8-77)

is the conversion

form indicative

is also used to control

to the Gemini

of the Command

oscillator,

(Figure

of the radar

of the 0 and i subthe sending

of the

Spacecraft.

System

the sub-bit

of a pre-acquisition

detector loop.

8-28B CONFIDENTIAL

in a

The variable

at a rate of 253 cycles p_r second,

F

is held

is insensitive

CONFIDENTIAL SEDR 300

"__

PROJECT

_"_7T7-_

GEMINI

_0

W_. Figure 8-77

Decoide,r Block Diagram 8-284

CONFIDENTIAL

___

_

-_

CONFIDENTIAL

PROJECT

GEMINI i

to lesser frequencies.

The modulated radar transmission is applied to the detector l in two forms, the transponder receiver video pulse and a pulse in synchronism with the leading edge of the video.

The sync pulse iS applied to the oscillator

thereby causing the frequency to increase to 256 cycles per second and synchronizing the early and late gates to the incoming video pulse.

The early gate and late gate, initiated by the variable

frequency oscillator,

for tracking the interrogate

and detecting

mission

pulse repetition

frequency

of the pulse corresponding to the binary sub-bit 0.

each 0-75 microseconds

are

the trans-

The two gates are

in width and are so related that the trailing edge of the

early gate abuts on the leading edge of the late gate. gates is slightly more than the video pulse.

The combined width of the

The video pulse is to be centered

equally between the two gates; any deviation frsm this condition will result in an appropriate

control voltage

The radar modulation

applied to the variable frequency

is determined by observing the presence

oscillator.

of the radar trans-

mission in either the combined early and late gate or ithe one gate, a 1.5 microsecond gate occurring The continuous variable

15.2 microseconds

transmission

from the leading edge of the early gate.

of the sub-blt 0 enables the synchronization

frequency oscillator.

of the

A slow frequency control loop provides memory so

that a command message may be sent and the oscillator iwill maintain the correct 0 and i time relationship.

The sub-bit detector provides a 25 microsecond pulse over the message line to i indicate a i and a 25 microsecond pulse over the message complement line to indicate a O.

These pulses, along, with a sync pulse iwhich occurs for either

f

0 or l, are then coupled to the computer.

8-285 CONFIDENTIAL

Figure 8-78EncoderBlock 8-286 CONFIDENTIAL

Diagram

CONFIDENTIAL

PROJECT

GEMI

J

C(X4WAND LINK ENCODER The command

link

encoder

into the encoder

(Figure

controller,

via two completely

communication

the rf link using

the rendezvous

after

maneuver

The co-_and address,

link message

a system

the message, system

128 possible

The task

word

is undesirable

entered

by two octal pilots.

encoder

controller

breaker

panel.

through

a twelve

into the infobit

switches The pilot

located

word.

bits,

vehicle used

is

the link used

bits,

The initial bits

are fixed

information

is provided digit

below

bits,

switches

a particular

c_nd

shift register current

switch,

a vehicle portion

of

and the

in content.

thereby

switches,

The

allowing

number.

magnetic

each having

An octal

is selected

with a list showing

establish

c_nds.

seven

standpoint.

and slightly

bit multiaperture

of the ET

factors

and a binary

three

The encoder

of the interrogate

actuation

initially

as a carrier,

of two information

information

from a human

of the 128 possible

which represent

means

The channel

information

function

by manipulating

and the corresponding

for each

of 12 binary

up of seven

a c_nd

states,

mands

is made

to the target

umbilical

consisting

of three

entered

c...... _nds.

of entering

spacecraft

address

pilot,

channels.

and a c<mmnd

consisting

c<.-_._ndfunction

Sgacecraft

is the hardline

address,

to link the c_nds

radar transmission

is comprised

the vehicle

address

is provided

by the Gemini

separate

the docking

8-78)

The message

core sh_ft

form of coding,

for use by the the individual

is entered

aft of the right a unique

current register

word, are J as magnetization states pulse

generated

by the

routing

switch.

8-287 CONFIDENTIAL l;

into the

path

in the encoder

interrogated of magnetic encoder

com-

switch/circult

The setting iof the encoding function

binary

switches, and encoded cores by

subsequent

to

CONFIDENTIAL

PROJECT GEMINI

The twelve information bits are shifted sequentially in information bit message (1) and message complement (0) form from the information bit shift register and further encoded, pseudo-random

one at a time, into another shift register in accordance with

sub-bit code.

Each is encoded into five sub-bits which are

shifted sequentially in sub-bit message (i) and message complement (0) form at a 256 pulses per second rate to the hardline waveform coder.

The complete

message format, as a consequence of the encoding process, is a serial group of 60 sub-bits.

For the hardline link the binary coded message is presented to the

sub-bit detector,

located in the transponder,

as bipolor return-to-zero

signals.

For the rf link, the sub-bit message and message complement signals are pulse position modulated by the rf waveform coder in the encoder and are connected to the grid modulator of the radar.

The method of pulse position modulation used

will cause a normal radar pulse, indicative of the sub-bit message O, to be transmitted in the first defined time slot while a sub-bit message I will cause transmission

of the rf pulse delayed 15.2 microseconds

position.

8-288 CONFIDENTIAL

from the normal, or 0

--_

_ONFIDEN_flAL

RENDEZVOUS

EVALUATION

POD

TABLE OF CONTENTS T I TLE

PAGE

SYSTEM DESCRIPTION. . . SYSTEM OPERATION ............ SYSTEM UNITS. . . _

. ......

8-291 8-291 8-294

ANTENNA SYSTEM FLASHING LIGHT BEACONS . . . =.... SQUIB BATTERIES ....... .... RENDEZVOUS POD COVER .... i. • • •

8-289 CONFIDENTIAL i

8-294 8-295 8-296 8-298

.-

CONFIDENTIAL SEDR 300

: .

IL_,,,j_,,_

PROJECT

GEMINI

BEACON

HINO

ASSEMBLY

LIGHT

-

-._/

) BOOST REGULAIC

BATTERY

SQUIB

_

_b PIRAL ANT ENNA

BATTERY

_ I

i

/

J ANTENNA

SPIRAL ANTENNA

F LASHLNG LIGHT BEACON

TRANSPONDER

Figure

8-79 Rendezvous 8-290 CONFIDENTIAL

Evaluation

Pod

CONFIDENTIAL

PROJEC

I

3ON

__

SEDR RENDEZVOUS

EVALUATION

POD i

i SYSTEM DESCRIPTION The Rendezvous Evaluation Pod (REP) (Figure 8-79) is _n i assembly used during Gemini Spacecraft mission number five to simulate the!Agena Target Vehicle. The t

REP consists of a transponder, two antenna systems, t@o flashing light beacons, i I and two squib batteries.

The transponder is nearly i_entieal to the transponder

to be installed in the Agena.

The flashing light beacons, which emit 80 + 1

flashes per minute, are visible for approximately

twenty miles.

These beacons

are to enable the crew of the Gemini to gain tracking t experience by visually observing the REP in space.

Observations are at meas i zred distances from the i

spacecraft against both earth and sky background.

This experience is used in i

determining the placement and intensity required for the Agena acquisition lights. The REP also provides a means of studying the man/equipment interface problems i

l

which might be encountered

during an actual rendezvou_ mission with the Agena.

The REP was installed in the center of the equipment spacecraft

(Figure 8-79).

Thermal protection

provided by the rendezvous pod cover.

_dapter section of the

for the REP prior to ejection is

The REP is eje _ted into orbit by a

pyrotecbnlc charge, after the spacecraft has been ins _rted into a satisfactory orbit.

SYSteM OPERATION During the first 65 minutes after lift-offt the EEP remains stationary in the

iI

equipment adapter of the spacecraft (Figure 8-80). spacecraft near the end of the first orbit.

The REP is ejected from the

Other ac _.ivltiesrelated to the

EEP occur primarily during the second orbit.

8-291 CONFIDENTIAL

CONFIDENTIAL SEDR300

:S.,_ _

D COVER

iii::::ili!ii!'_ii::_iii!_ _!::

':

_.,":::_L_ _:_:!::.:.. "_:_ RIGHT

SWITCH

'CIRCUIT

BREAKER

PANEL

i !i!i _!

_11|

THB RENDEZVOUS POD COVER IS SHOWN IN THE MOUNTED POSITION SkIIELDING THE REP. THE COVER PROTECTS THE REP FROM THE EXTREME HEAT OF THE SUN IN SPACE.

!iii :::!:i:: :::;::

:

;:;::; ::

:

...

;::

POD COVER (OPF WHEN COMPRESSED)

REP TURN-ON REP

SWITCH

:i::i:: :! :iii

SWITCH

[]

ASSEMBLY

THE RENDEZVOUS POD COVER IS SHOWN LEAVING THE ADAPTER SECTION. EJECTION THE GUILLOTINE CUT THE CABLES SPRING HASASSEMBLY HOLDING DIE COVER AGAINST THE TUBULAR POSTS. THE VELOCITY WI',ICH THE SPRINGS IMPART TO THE COVER IS 100 FEET PER SECOND.

(REP PYROTECHNIC CHAR GE INSIDE)

RBP

EJECTION

[] lATELY AS THE REP IS EJECTED, THE MO PLUNGER TYPE SWITCHES ON THE REAR OF THE REP ARE RELEASED CAUSINg THE BEACON LIGHTS AND THE TRANSPONDER RE-

Figure

8-80

Mounting

and

Ejection

of Cover 8-292

CONFIDENTIAL

and

Rendezvous

Evaluation

Pod

CONF|DENT_AL

....

PROJECT GEM! so. 300 Nl! i

The REP has two spring-loaded, the battery

plunger-type

power to the beacon

these normally conserved.

closed

The pilot

switches will

to the first perigee.

lights

depressed

the REP

The spacecraft

(Figure

8-80) which

and the transponder.

are held

eject

switches

(ope_)

Prior

to ejection

so that power

approximately!fifteen

control

minutes

is prior

will yaw left 900 and the POD EJECT i

switch located

on the right

be depressed.

Pushing

(Figure

8-80).

the POD EJECT

One charge

the two cables

switch/circuit

drives

shown in Figure

breaker

switch

activates

a guillotine

8-80.

pan@l

type

The cables,

(Figure

8-80) will

_wo pyrotecbn_ c charges cable

cutter which

when released,

allow

severs the two

i

compressed

springs

to expand,

the rear of the spacecraft. I00 feet per second. delay, propells

thereby

propelling

The relative

The other

charge,

the rendezvous

ejection

initiated

the REP from the spacecraft

with

velocity after

pod cover

of the cover

from is

an 80 millisecond

the relative

velocity

time

of S._

i

feet per second. since the ejection the ejection

The cover will velocity

of the cover

If the retrograde

of the REP,

no tumbling

in locating

the exact

is expected.

is much

the ejection I

great@r

would

center

For successful

one revolution

the earth's

conditions.

of the REP is desirable

the mission.

between

outside

hot and cold temperature

or tumble

with

of the REP

than and is prior

to

of the REP.

Since the REP will be orbiting extreme

not interfere

to allow

Therefore, uniform

thrust were result.

operation,

per minute

applied

Since

of gravity,

atmosphere,

experience

a slow rate of rotation

hea_ing

and cooling

throughout

to the

exact

center

a very minute

error

is anticipated

a slow tumble within the rate of tumbling

and one revolution

8-293 CONFIDENTIAL

it will

of gravity

the required

limits

of the REP will

per hour.

be

CONPIOENTIAL

PROJECT GEMINI

Immediately upon ejection the compressed, sprlng-loaded, plunger-type switches are released causing the transponder receiver and the two flashing light beacons to become operational.

It is estlmated that the flashing lights on the REP at

20 nautical miles are equivalent to the intensity of a third magnitude star. Thus, a z_.nge of 30-35 nautical miles between the I_ desired to assure exceeding the visible _mlt

and the spacecraft is

Of the _EP lights.

The _

and

the spacecraft trajectories will be designed so that the crew can make visual observations of the REP up to the -_m and darkness.

observational distance in both daylight

The ejection of the REP and the maneuvering of the spacecraft is

performed over ground tracking stations to provide gro_

monitoring capability.

SYSm_M UNITS TRAWSPO_R The transponder of the _

(Figure 8-79) is nearl_videntical to the transponder

of the Agena Target Vehicle. l=_gest c_onent

of the REP.

The transponder, i0 by lO by 20 inches, is the For this reason, the transponder serves as the basic

cowponent to which all other components are attached.

For a detailed discussion

of the operation of the transponder, refer to the Rendezvous Radar System portion of this section.

AFtrA

SYS_

The REP radar antenna systems (Figure 8-79) consist of two clrcularly polarized double-spiral antennas and one dipole antenruaarray. same t_e

and size as the ante-ms

anten_

are the

used on the Agena, however, there are several

slight differences in the manner in which the anten_ ante-hAs of the I_

The _

are mounted.

The spiral

extend outward approximately two inches from the case of the

CONFIDENTIAL

CONFIDENTIAL SEDR300

_-

'_"

i

transponder.

In

comparison,

the

spiral

antennas

of

the

A_ena

are

mounted

flush

i with

the

outer

surface

of

the

Asena.

The

dipole

antenna

of

the

REP is

mounted

i

c_ the Agena

end is

of

a Wo-foot

mounted

long

fixed

on an elect_call_r

operations

of the two antenna

capability

of transmitting

in this manusl

FLAS_

boom,

whereas

old,ted,

systems

are the same. Refer

discussion

(_ipole

retractable

and receiving.

for a detailed

the

antenna

boom.

the

The electrical

All antennas

have the

to the Rendezvous

of the antenna

of

system

Radar

_stem

operation.

LIGHT _C_S

The REP has two toroid-shaped, are the same t_pe

target

of the REP so that at beast lights

The flashing each mounting

25-watt

lights as the I00 candlepower

are used on the Agena

The beacon

xenon-filled,

assist

The lights

one light

is visible

the crew in _-euvering

of the lights case.

vehicle.

Agena

is regulated

The chargin8

beacon

lights.

acquisition

are located

lights

lights which

on opposite

sides

tot he crew from any direction. the spacecraft !

by a resistor-capacitor

circuit

These

is designed

relative

circuit

So that both

to the

located

Lights

operate

i simultaneously

and ass_ne

of flash.

This rate

per minute

however

can be manuall_

the optim_

have

a life expectanc7

more

th_n sufficient

one A__nd_ one half

the flashing

of the li_t

adjusted

i i

within

having

_ range

the higher

flashes,

since the R_

rate

of 75 to 90 flashes

rate is _0 .+ I flashes

of 2_,000

time,

rate

_r minute. The lights ! or approxima_e_7 5 hours. This is

will

be used ifor approx_mtel_

hOUrS.

8-295 CONFIDENTIAL

in

CONFIDENTIAL

PROJEC---T--G

Each

beacon

light has a thermal

strap is a ¼ inch thick the heat generated plunger-type

by the light.

switches

to flash the zenon filled

the lighting

SQUIB

system

is shown

lamps.

in Figure

through

two redundant

The flashing

voltage

dissipate

circuit

to the 2500 volts

The electrical

schematic

diagram

of

8-81.

BA_r_RIES

The REP utilizes batteries

two low impedance,

24-volt,

are the same type of squib battery

8-79 shows one of the squib batteries The other battery

The squib batteries

ponder

and the two beacon

served

from a separate

During

spacecraft

lights.

mission

number

that the batteries

the lights

is the limiting

of the batteries

the internal entitled

structure

Electrical

The battery

supplying

The operating

used

attached

The

squib batteries.

in the spacecraft.

Figure

to the case of the transponder.

serve

as the power

The transponder

squib battery

a very small time, approximately necessary

silver-zinc

is on the other side of the REP and cannot be identified

the illustration.

weight

battery.

the battery

bonding

is used to help

are connected

silver-zinc

to increase

The thermal

copper which

The lights

to a 24 volt

-_

strap attached.

strap of laminated

uses a dc to dc converter required

bonding

EMINi

and operate

5 the REP will one orbit

possess factor.

be required

or 90 minutes.

an exceptionally

lights are each

of one another.

to function Therefore,

long life.

of the squib

For a detailed battery,

refer

for only

it is not

The life of

Due to the short usage period,

and operation

power

for the trans-

and the beacon independently

can be held to a minimum.

Power System

source

in

the size and discussion

of

to the section

.

to the transponder

level of the transponder

is augmented

is 28.3 volts

8-296 CONFIDENTIAL

by a boost

and the rated

regulator.

voltage

CONFIDENTIAL

,f_.: ___,__

_,_

PROJECT SEDR300GEMINI,,

o

o_

_-'_'_'-'_J

TRANSPONDER J

SPIRAL ANTENNA

J7_

R'[ 02

XBT:

I

:_

_ _ B A1

_ _ s a _ _

_0_

P7a3

J701 BT70! 24V TRANSPONDER BATTERY

A70I BOOST REGULATOR

XDS7_

_XDS702

I II I Figure

8-81 Rendezvous

Evaluation 8-297 CONFIDENTIAL

Pod

Schematic

Diagram

CONFIDENTIAL. _.

SEDR300

PROJECTGEMINI

of

the

squib

resulator is

to

be

As the

the

is

_e_riss

so

times.

squib

that

to

the

_zVOUS

PODCOVER

directly

craft.

The cover

intense

heat

has

over a

sun's the

is the

which

.00035

inch thereby

required

limits.

cover.

tuhu]A_

posts,

Two Of the pins

are

used

for

the

voltage

the

to

a_d

like

necessary of

that

the

maintain

a beost

boost it

at

regulator the

required

in

in

extend

of to

the

the

8-81

the

voltage Boost

in

regulator

transponder

for

which

past

is

at

further

all

_nformation

structure

This

to

cover

the

the

protect

is

made

I_P,

The

silvered

temperature

Of

are

8-298 CONFIDENTIAL

the

in The

of the

of

a

outer

surface

to guide

other

two

the

is space-

REP from tubular face

the metal

of

reflects

REP remains

provided

terminate cover.

which

section

stretched.

located align

plane

serves T_e

cloth

the

oval,

equipment-adapter

space.

diagonally properly

input

decreases,

a variable

voltage

an

surface. that

battery

adding

Figure

is

the

umbrella

rays

ensuring

to

8-80)

silvered

which

by

volts of

squib

employed.

fiberglass

thick

posts

28.3

are

I_P an

sun's

the

decrease

diagram I_P

the

of

The additional

(Figure

a thin

rays,

Four

guide

of

behind

of

is

it

The purpose

voltage

a constant

pod cover

located

the

sehematic

batteries

frame

and

is

on how the

The rendezvous

system.

input

battery.

there

Refer

the

therefore

level.

compensates the

2_ volts,

into

cons,,wd

regulator with

only

transponder

operating

power

series

is

incorporated

increase

28.3 volt

Boost

battery

support pins. posts

the the

within

the These terminate

cover

CONFIDENTIAL.

....

SEDR 300

in sockets

which

house the spring

by two cables which pass through The

other

and

a nut.

tension

Ejection

a pyrotechnic

end

of

This

to

the

each screw

cable,

guillotine

cable

is

and

nut

causing

the pilot

the guillotine-type

attached serves the

cables allows

to as

spring

to the cover of iOO feet

sockets,

the

a

and tubes.

to

be

Both cables

and

pod is

cover used

by to

springs

a pyrotechnic

the two cables.

to expan&,

per second.

a

assembly. screw

apply

compressed.

switch,

severs

in place

to the l_P support

rendezvous

turnbuckle

Is held

in the same m_--er as the ejection

cutter which

the two compressed

The cover

and are anchored

pushes the POD EJECT cable

assembly.

the springs,

of the cover is initiated

REID. When

velocity

Pass through

ejection

thus

The cables

after ejection.

8-299/300 CONFII)ENTIAL.

charge Cutting

imparting

of the activates the

a relative

remain with

the cover

TIME REFERENCE SYSTEM

TABLE OF CONTENTS TITLE

PAGE

SYSTEM DESCRIPTION ooooooooooo 8-303 SYSTEM OPERATION oeooeoeoooeo 8-304 ELECTRONIC TIMER oeooooomoo 8-306 TIME CORRELATION BUFFER..... 8-324 MISSION ELAPSED TIME DIGITAL : CLOCK .......... ,...... 8-326 EVENT TIMER ooooooooo4ooe 8-333 ACCUTRON CLOCK ....... • • • 8-339 MECHANICAL CLOCK .......... 8-340

8-301 CONFIDENTIAL

CONFIDENTIAL SEDR300

•_

--MISSION DIGITAL

ELAPSED TIME CLOCK

(s/c6, 8a uP) TIMER

MECHANICAL

Figure

8-82

Time

Reference

System 8-302

CONFIDENTIAL

Equipment

Locations

CLOCK

CONFIDENTIAL

PROJEC

i , i

SYBT_M DESCRIPTION ,i , ,,,, The Time Reference System (TP_) (Figure 8-82) provides _he facilities for perform-

i

ing all timing functions aboard the spacecraft.

The s_tem

is comprised of an

electronic timer, a time correlation buffer, a mission elapsed time digital clock, an event timer, an Accutron clock and a mechanical clock.

The event timert mission

elapsed time digital clock, Accutron clock and mechanic_l clock are all mounted on |J

the spacecraft instrument panels.

The electronic timeX is located in the area i

behind the center instrument panel and the time correl_tion buffer is located in back of the pilot's seat.

_..

The electronic timer provides (I) an accurate countdow_i of Time-To-Go to retrofire (TTG to TR) and Time-To-Go to equipment reset (_G tion for the P_

to TX)_ (2) time correla-

d_ta system (Instrumentation) and the bio-med tape recorders,

and (3) a record of Elapsed Time (ET) from lift-off.

The Time Correlation Buffer (TCB), conditions certain Output signals from the electronic timer, making them cempatible with bio-med_ I

voice tape recorders.

Provision is included to supply buffered signals for Del_nt

of Defense (DOD)

experiments if required.

The mission elapsed time digital clock (on spacecraft 6 thro__gh12) provides a digital indication of elapsed time from lift-off. fr_

The i_igital clock counts pulses l the electronic timer and is therefore started and istoppe_ by operation of the

electromlc

timer.

8-3o3 CONFIOWNTIAI.

CONFIDENTIAL

PROOECT

The event timer provides aboard

the spacecraft.

with a visual electronic

the facilities

for t_m_ng

It is also started

display

timer

GEMINI

of ET during

at lift-off

the ascent

should fail, the event

various

phase

timer

short-term

to provide

functions

the pilots

of the mission.

In case the

may serve as a back-up

method

of

timing out TR. The Accutron c_nd

clock provides

pilot.

of external

The clock is powered

power

The mec_n_cal date.

SYS_ Four

clock provides

method

of Greenwich

by an internal

Mean

Time (G_T)

battery

for the

and is independent

or signals.

In addition,

emergency

an indication

the pilot

it has a stopwatch

of performing

with an indication capability.

the functions

of GMT and the calendar

The stopwatch

provides

an

of the event timer.

OP_TION components

Accutron

of the Time Reference

clock and mechanical

two _ining

components

are dependent

diagram

of the Time Referemce

The electronic time-of-day spacecraft

portion mission.

elapsed

on ou.tput signals

timer, mission

System

of the mechanical The mechanical

clock clo_k

period.

The electronic

a reaote

signal from the Sequential

operate

starts

System

CONFIDENTIAL

The

conciliation

A functional

8-83.

clock, Accutron continuously,

and Accutron

timer

timer.

timer,

other.

clock and time

in Figure

time digital

event

of each

the electronic

is provided

elapsed

timer,

independently

time digital

from

the pre-launch s_rt

(electronic

clock) function

(mission

buffer)

System

clock

operating

clock during

are started

and the the during

upon receipt

at the time of lift-off.

of

CONFIDENTIAL SEDR 300

"_

I-

,MEREEE'ENCES_';;7_C_ "--I TR (EMERGENCY), ACCUTRO N CLOCK

GROSS TIME,

ELAPSED TIME (SHORT TERM)

[ J

JI '

J

• O.M.T. DISPLAY CLOCK • STOP WATCH

._MMISSION ELAPSED TiME

L

TR (BACK-UP),

CREW

ELAPSED TiME (SHORT TERM)

TR-2B,_ SEC, TR-30SEC

J

SECONDS)

J

• CALENDAR DAY I (MINUTES AND MECHANICAL

1

I I

--Z _O

E,ME O,G,TAL --

_

I_

NOTE

* GROSS TIME FROM LIFT OFF

CLOC_.._.______ b,.,.,ss,oN ELAPSED

D

I

EFFECTIVE SPACECRAFT 6, 8 AND

I

UP.

Ji

INSERTION

• DECIMAL DISPLAY _AINUTES AND SECONDS) • COUNT UPOR DOWN

--

,

--

UNIT

--

L IFT-OFF SIG NAL

SEQUENTIAL SYSTFJv_

O

gz__

J |

T R (AUTOMATIC FIRE SIGNAL) TR -256 SEC, TR -30 SEC

J

TIME-TO-GO

TO TRAND

1

I

TX UPDATE ON-BOARD



ELECTRONIC

J l

_DATA REQUEST

TIMER

TIME-TO-GO

• COUNT DOWN TO • COUNT DOWN COUNT UP ELAPSED TIME FROM LAUNCH

COMPUTER

TO TR ELAPSED TIME

|

I

INSTRb_ENTATION ELAPSED TIME AND TIME-TO-GO

TO T R

D,

SYSTEM

RECORDER TIME CORRELATION BUFFER

ELAPSED TiME l

L

I " .

1

_..I

Figure

8-83 Time

Referenee

System 8-305

CONFIDENTIAL

Punetional

Diagram

VOICE TAPE RECORDER

CONFIDENTIAL

PROJ

If the lift-off timer

can be

mission

signal is not received

started by actuation

elapsed

upon receipt

time digital

of output

During the mission, the mechanical crew.

however,

from the Sequential

of the START-UP

started

Accutron

System,

buffer

timer

timer.

The

start operating

timer.

clock

and the stopwatch

and stopped, manually,

the event

the electronic

switch on the event

from the electronic

the event timer,

At lift-off,

IN I

clock and time correlation

signals

clock can be

the Sequential

EC---'T'-GEM

portion

at the descretion

is started by a remote

of of the

signal from

System.

ELECTRONIC

General At the time elasped

of lift-off,

time and counting

zero to a maximum functions

the electronic

by insertion

station,

throu6h

Data Insertion mature update,

Unit

countdown

duration.

the tiuer will

Updating

not accept

of counting

(DCS),

of equilment

any new time-to-go

to be loaded with

8-306

CONFIDENTIAL

the

via the Manual

inadvertent,

or personnel

error

pre-

during

of less than 128 seconds

of new data of less than the inhibit

cause itself

during

either by a ground

To prevent

failure

are written T_G to T R from

at any time

or by the crew,

computer.

reset

of two hours.

may be accomplished

Co_=_and System

of TR as a result

Upon receipt

is capable

up

up from

and equipment

of time which

reset from a maximum

(MDIU) and the digital

the timer will

values

by the timer may be updated

of new data.

the Digital

certain

of counting

ET is counted

The retrofire

The timer

of 2_ days and to equipment

The TTG to T R data contained mission

2_ days.

down to zero from

into the timer prior to lift-off. a maximum

its processes

down TTG to TR and TTG to T X.

of approximately

are counted

timer begins

time mentioned

a time in excess

of two weeks.

above,

CONFIDENTIAL

__.

SEDR300

The

TTG to

operates

T X function

while

telemetry. via

the

the

range

is

is

As the

spacecraft

comes

a TTG to

of

the

done

from

If by

the

the

within

crew,

_G

using

is

operation computer

reset

certain

a ground

range, Then,

timer

of satisfactory

to over

ground

electronic

use of the digital

passing

the

the

the

serves

timer.

station,

reset.

confirmation through

TX in

ground

may be

Information

timer

spacecraft

DCS,

it

the

the

automatically

data,

of

station

spacecraft

TX reaches

station

is

the

MDIU and

and

to

insert

d_ltal

continuously

inserts, out

the

equipment the

displayed;

readout

of

time

computer.

may be made by the readout

MDIU display

with

moves

zero,

unable

which

equipped

ground

the

to

not

I station

the

as

equipment

however, of _

data

capability.

NOTE The mission pulses

elapsed

time

digital

from the electronic

no loss of pulses,

will

clock

timer

and, ass_ning

indicate

time recorded

in the electronic

digital

clock

does not, however,

elapsed

time word

counts

the elapsed timer.

The

read out the

from the electronic

timer.

Construction The electronic

timer

inches an_ weighs

(Figure

8-8_)

is approxlmately

about ten pounds.

6 inches

It has two external

x 8 3/4 inches

connectors

x 5 1/2

for interface

i i

its associated

systems.

The enclosure

for the unit

is! sealed

to keep

out moisture

I

but is not pressurized.

The timer

utilizes

a modular

Construction,

containing

I i

eight modules (I)

crystal

which

are wired

oscillator,

(2)

directly t4m_.g

into the enclosure.

assembly,

8-3o7 CONFIDENTIAL

(3)

register

The modules control

are:

assembly.

with

CONFIDENTIAL SEDR 300

EVENT TIMER

[DMISSION ELAPSEDTIME DIGITAL CLOCK

A

//

ljill

MECHANICAL CLOCK

10

oI

ACCUTRONCLOCK

NOTE [_EFFECTIVE

SPACECRAFT 6s 8 AND UP.

TIME CORRELATIONBUFFER

ELECTRONICTIMER

Figure

8-84

Time

Reference

System

8-308 CONFIDENTIAL

Components

CONFIDENTIAL

:@ (4)

memory

control

relay assembly, components

_oo

PROJECT

assembly,

and

(8)

(5)

power

GEMINI

memory

supply.

are used in all modules

assembly,

Printer

except

(6)

driver

circuit

the crystal

boards

assembly,

(7)

and solid-state

oscillator.

Operatlon The electronic counting

timer

operation

an add/subtract 8-85).

is basically

for each

program

ET or a TTG, is modified

A storage

register

is provided

controlled pulses

oscillator

provides

operations

take

pulses

It performs

the

every

i/8 seconds.

operation,

a binary

of time. words

of the three

(Refer to Figure representing

Magnetic

between

timer

for data transfer

word,

counting

funtions

between

core storage cycles.

and another

the timer

oscillator

necessary

place in very of toggle

for the timer

of the timer.

of accuracy

small fractions flip flops

standard

required

outputs

The type

of

for the timer

of a second.

whose

for developing

whose

The oscillator

provide

the actual

is timing

operation.

timer

of time is further 32 bit times,

for the operation

the high degrees

to a series

The electronic

is used as a frequency

utilizes

divided

a 32-word

into

time program.

32-word

times.

and each bit time is divided

the shortest

pulses

used in the timer

One bit time

is equal

into

operation

to 122 m4eroseeoz_s

That is, each

32

S pulses

8-_9

times.

into

S pulses

and are 3.8 microseconds

and one word time

CONFIOI=NTIAI.

I/8 second

Each word time is divided

is

and the

computer.

the t_mlng

coupled

counter.

(ETj TTG to TX, and TTG to TX) by

the binary

for each

register

binary

a new amount

or remember

for use as a buffer

A crystal

....

to represent

are used to store

digital

is repeated

of the counting

registers

provided

of its functions

which

In each repetition

an electronic

are

long.

3.9 milliseconds.

CONFIDENTIAL SEDR300

:-

___._,_

PROJECT

GEMINI

_j

TIMED EVENTS (RELAY CLOSURES)

8 0 Z

_o

k

0 Z

_

o

A

8

'_

'

u

N

_

2 1'

_ _

e 5

8_

_

8

0

Figure

8-85

Electronic

Timer

Functional

8-310 CONFIDENTIAL

Block

Diagram

-

CONFIDENTIAL.

PROJECT _.

SEDR 300

It is pulses toggle

of these

Start Circuit

Timer

operation

spacecraft System

durations,

and their multiples,

is initiated

Sequential

when a 28 vdc start

System

is transmitted

or the event

to the electronic

the event timer is generated

the unit is placed causes

when

umbilical.

pz_maturely

to the countdown

Countdown

and

The countdown

and time

operation

controlled

oscillator

(Refer to Figure

every

the output

switch

of a signal

by a clock-hold

control

the

the Sequential the one

on the face

from either Until

of

source

lift-off,

the

s: gnal from the AGE via the

that th t timer

of lift-off.

signal

either

to be applied

of the crystal

will

not be started

Actuation

of the clock-

to a gate

controlled

in the timing

oscillator

to be

flip flops.

decoding

network,

operations

is initiated, is coupled

8-86).

Twelve

and five in the register each

take place iprimarily

the 1.048576 to the first

megacycle

of a series

of the flip flops control

stage of which

two input pulses.

eight pulses

toggle

from

Time Decodin 6

When timer

dividing

by the

at liftoff;

to be ac ;uated.

is done to assure

a positive

This gate allows

coupled

module

This

relay

is received

automatically,

Receipt

and will be at zero at the time

start relay causes module.

are produced

The signal from

the UP/DN

in the UP position.

relay is held in the reset position

signal

timer.

timer,

the set side of the clock-start

spacecraft

which

in the timing module.

flip flops

Timer

from

GEMINI

The output

module.

output of

are contained

one square wave of the final

per second.

8-311 CON FI DENTIAL.

module.

of the crystal-

17 toggle flip flops in the timing

The flip flops

produces

frequency

in the timing

form a frequency output

stage

pulse

for

in the series

is

CONFIDENTIAL SEDR300

_.--_ _ "_E. • _

_,_'_

"

PROJECT

_=_-_

GEMINI

__

8 P.P.S.

16 P.P.S.

_l _l

__

F_ r_

NO.

17

NO.

16

___

_

V--1

t NO.

32,768 P.P.S, 65s 536 P.P.S.

_

C_

J I_FO

V-q

/_

GATE (TYPICAL)

TIME DECODING

5

t_F1

_l

131 _072 P.P.S.

NO.3

262t |44 P.P.S.

S

GATE INPUT

_

Z O

-

z 3

Figure8-86 Schematic Diagram,

Frequency Division & Time 8-312

CONFIDeNTIAl

Decoding

CONFIDENTIAL

PROJECT __.

GEMINI

SEDR300

Outputs of all but the first two stages of the countdown circuitry are utilized to develop the timing pulses necessary for timer operations.

Output pulses from

either the i or the 0 side of an individual flip flop may be used; however, the polarity of the pulses from one side will be 180° out of phase with those from the other side.

Pulses from the flip flop outputs are supplied, in certain

combinations, to gate circuits in the time decoding section. receives

Each gate circuit

several input pulse trains and produces

outPut pulses which are usable i for the timer circuitry (Refer to Figure 8-87e). Basi_ally, a gate will produce output pulses which will have the pulse width of the

_rrowest

input pulses and

the frequency of the input pulse train with the wides_ pulses.

If the polarity

of one input is reversed, the time at which the outpu_ pulse occurs, will chs_e F_

(Refer to Figure 8-87b).

Operational

Control

Two complete modules are required to encompass all of ithe circuitry necessary to perform the control functions

in the electronic

timeri

The register

control

module primarily controls the transfer of data into and out of the timer. memory control module

directly controls the operatiom

of the magnetic

The

storage

registers in the memory module.

The register control module supplies the control signals which are required to perform the operations directly associated with the transfer of time data. utilizes the various c_d

and clock signals from the other spacecraft systems

to produce its control signals. appropriate circuitry to: (i) process), (2)

It

The control signals are then supplied to the receive a new binary data word (as in the updating

initiate the shifting operations of the proper storage registers l

to write in or read out the desired time data (ET, TX, or TX), and (3)

8-313" CONFIDENTIAL

supply

CONFIDENTIAL

PROJECT

GEMINI

data, read out of the storage registers, to the proper timer output termlnal(s) to be transferred

to the system requesting

it.

The memory control module directly controls the operation of the magnetic storage registers

and performs

the arithmetic

computations

of the counting process.

Inputs

from the timing and register control modules are utilized to develop the shift 8nd transfer output pulses ters.

for shifting data words into and out of the storage regis-

These pulses are developed separately for each register.

Both control modules are made up of rather complex and overlapping logic circuitry. and transfer

networks of

The memory control module also employs shift current generators

switches, as output stages, to develop the required power capabili-

ties.

Storage Register Operation The magnetic storage register to ET, TX, and TX are used to store or remember binary words of time data. registers, as required, spacecraft systems. accomplished,

These data words may be shifted out of their respective

for the counting operations

and for transfer to other

The transfer of data into and out of a storage register is

serially, with the Least Significant

Bit (LSB) first.

A storage register is comprised of a series of magnetic memory cores, each of which is capable of storing one binary bit of time data.

This capability is based upon

the characteristic of a magnetic core to saturate in one of two directions when a cu_ent

pulse is applied to one of its windings

(Figure 8-88).

Saturation in

one direction represents a binary I and indicates the presence of a data bit. Saturation in the other direction represents a binary 0 and indicates the absence of data bit.

The storage registers for ET and _

8-B14 CONFIDENTIAL

to TR each contain 24 magnetic

CONFIDENTIAL SEDR300

j- _ •

____

PROJ

ECT

_-'"

G EM,

,

(a) INPUT FROM F.F.

J_

_I

GATE OUIPUT

NO.

3 ("O"

SIDE)

3 ("0"

SIDE)

SIGNAL

(b) INPUT

l

l

'

I

]

J

_

_

J

_

[-I Figure 8-87 Time

[_

Decoding

--

VI Gate Inputs

FROM F.F.

NO.

'NPUTFROMF.F.

NO.4("I"SIDE)

INPUI[ FROMF.F.

NO.

5("O"SIDE)

I- oA ou u so.A and Outputs

(Typical)

::! :!:_:!: _!_ :_:!:_: _:!_:!: :!:__:_:_:i_ :i:_:_ _:!:i_:!:!:i:!:!:!:!:i:i:i: :_:_:_: :::_:_:_ :::::::::::::::::::::_:i:i_i_!_i_!_!_:_`,._:_:_:::::::::::::::::::::::::::::::::::::::::_:_!_ :!:!:!:!:!:!:!: :!:!:::::::::::::::::::::::: ::::::::::::::::::::::::::::::::::::::::: ::_:_ :::_:_: _::_:_:: ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: _:_:::! _:!:[_:_:!:_:_:: _i:_:_:_:_:i: ::::::::::::::::::::::::: :!:: :

CURRENT PULSE _

__

Figure 8-88 Magnetic

Core Operation

8-315 CONFIDENTIAL

CONFIDENTIAL

PROJ E-E"CT"GEMINI

cores and the register ET or TR consists

for TTG to TX contains

of 211bits, while

The use of the binary which

can represent Each data bit

time.

In looking

storage

the smallest

in a binary

represent

time

data word

its 2_ individual

increment

(i/8 second)

to as the LSB in the data word.

next bit

(representing

core number

successive By adding total

i/_ of a second)

22 representing

core representing together

is stored

in core number

Core number

of the data word.

I/2 second, back

that

of time represented

ET and TR registers

have capacities

of approximately

by totaling

of the word where binary the representative

The process by

of shifting

the occurrence

control

time

of a data word

the increments

of time

ones are present.

transfer

pulses

fr_

whenever

a data word

core number

continues,

i with each

of the preceding

one.

Thus,

it is found

the that the

2_ days and the TX register, to its representative

represented

may be

by the bit positions

For the data word

shown

in Figure 8-89b

is 583 3/8 seconds.

a data word

into or out of a storage

of the shift and transfer

gate preceding

store the

by all of the cores,

can be determined.

Conversion

represents It is

The sequence

through

twice

2_.

23, then would

of

of the

The data bit which

of the register

acc_plished

of data

increment

8-89a, the 24 sections

cores.

a time increment

the increments

two hours.

the storage

one individual

time capacity

approximately

word for

of 16 bits.

permits

represents

in Figure

referred

with

for TX consists

a binary

of time as small aB i/8 second and as large as 24

at the flow diagram

register

Therefore,

system for time representation

an amount

days.

a word

16.

each register

the control

is to be written

each bit time for a duration

are supplied

in or read out.

of one word

is controlled

pulses and by the condition

and its write-in

section

register

time.

8-_.6 CONFIDENTIAL

amplifier.

The shift

to a storage These

The actual

of a

pulses

and

register occur

once

flow of data into a

CONFIDENTIAL

_

PROJECT

GEMII 'il

storage register is controlled by a logic gate precee_ing the write-in amplifier for each register (Figure 8-90).

The count enable input of the gate will have

a continuously positive voltage applie& after lift-off has occurred.

The write-

in pulse input will have a positive pulse applie_ for i7.6m!crosecon_s _uring each i

bit time (122 microseconds).

These two inputs control the gate.

The result is

;

that a positive data pulse m_y pass through the gate qnly _uring a 7.6 microsecon_ perio_ _uring each bit tl_e.

When a binary data wor_ is to Be written into a storage register, its ind/vidual bits appear at the input of core number i as a series of current pulses.

When the

first current pulse (representing I/8 second) of the _tord flows through the input winding of core number I, the core is saturate_ in the binary i direction.

It

remains in this condition until a current pulse flows ithrough the shift winding of the core.

The shift pulse causes the flux of the core to collapse an_ reform,

switching the core back to the 0 condition.

When thi_ occurs, a voltage is

1 _evelope_ across the output win_ing of the core an_ the temporary storage capacitor is

cll_rged

through

the

wind.i_

from the

_ic_le

et_l.,

_en!

the

shift

pulse

d.ecays

anc1

a groun_ potential is place& on the transfer line, the capacitor discharges through the input winding of the next core, setting it to the ibinary i condition.

Whenever

!

a bit position of the incoming data wor_ _oes not contain a pulse, core number I i

is not switche_ to I.

As a result, its shift pulse causes no change of flux; no i i voltage is _eveloped across the output and the capacitor is not charged or disi charged..

Hence,

the

next

core

is

not

set

to

the

1 condition. !

Because

the

shift

pulses are applied,to all the cores in a register, simultaneously, it is assured. that e_ch one is set to the 0 condition before the transfer pulse (also applied. to all cores, simultaneously) allows the storage capacitors to _ischarge.

8-317 CONFIDENTIAL

When

CONFIDENTIAL

__'

PROJECT

GEMINI

(a) (DATA WORD FLOW-COUNTING PROCESS) STORAGE REGISTER I

SERIAL INPUT

I

2

3

4

"O"

"O"

"O"

"O"

5 "O"

6

7

"O"

"O"

8

9

"O"

"O"

10

1]

12

13

"O"

"I"

"O"

"O"

}4 "I"

15

16

17

18

19

20

21

22

23

24 I I

"O"

"O"

"O"

"I"

"I"

"I"

"I"

"O"

"I"

"l"

NETWORK ADD (OR SUBTRACT)

j

SERIAL OUTPUT

]

(b) (DATA WORD TIMEREPRESENTATION) LEAS'/ SIGNIFICANT

k_i:/SS

BIT

I/4S

1S

_rL_J1 "I*'

2S

4S

64S

rl r!_J1 "I"

"I"

"I"

"l"

512S

rJ

n

"l"

*'I"

DATA STORED IN WORD REGISTER

Figure ::::::::::::::::::::::::::

::: ::::::::i:

8-89Time

Data

:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ::::::::::::::::::::::::::::::::::::::::: :::!::

Word

Flow & Representation

: ::: ::: :: ::::::::i::: ::::::::::::::::::::::::::

'I

::::: :

:: :

:: :

:

::: :: :

: :

: :

:

::

:: :

:

I L

_TORAGE

_. REGISTER

SHIFT CURRENT

DATA WORD -_,_r_..._, IWR,,E A_'E'ER ,N I " -_ COUNT

ENABLE

I

_]

_,.,.J._L

_"D

_

l

R23

_

E24

_]___

IDATA

!T NSEE., --i

Figure

-

8-90

Schematic

"

Diagram-Storage 8-318

CONFIDENTIAL

Register

CONFIDENTIAL SEDR300

a complete binary

word has been

i condition

Reading

written

contain

a data word

into the register,

the binary

out of a storage

the _cores which

are in the

data bits.

register

involves

basically

the same processes

aswriting onein.

The data bits the register repetition

Counting

shift from first.

of the

left to right, with

An additional

shifting

21_ leaving

the bit in core number

bit is shifted

out of the register

with

each

process.

Operatlons

The counting data word

operation

for each

out of a storage

and writing completed

of the timer

register,

cycling

it back into the register.

in one word

time representation

The read and write

time

and is repeated

of the counting

the first data bit is shifted

consists

of reading

it throug h an arithmetic

(Refer to Figure

of the word is changed

portions

functions

every

8-89a.

i/8 s_cond.

by an increment

operation

out of a register,

a binary

network,

The operation

In the process,

is the

of I/8 second.

take place

the remaining

concurrently.

bits

As

shift one core

I

to the right, place,

leaving

the bit which

throught

core number has been

the arithmetic

is shifted 24.

shifted

circuitry

is the same for each bit

number i, completing

cycles

Before

the next

out of the register

and inserted

of the word.

out of the register,

The last bit then

I vacant.

back

Thus, when

shift

is cycled,

into core number

the bast bit

the arithmetic

the counting operation.

8-S19 CONFIDENTIAL

circuitry

takes

instantaneously, i.

The process

of the original

the first bit of the new one shifts through

operation

into

and enters

word

core number core

CONFIDENTIAL.

In the arithmetic

is supplied

separate

subtract

continues

coming

has been

produces

register

changed

time of the word. just as they were

amplifier,

output

of the new word. 0 to a binary

The remaining

to

up of combinations

similar,

the main

binary

I to the first bit position_

If there

is already

The carry

a i in that

operation

The positive

to the input a binary

0

signal is then

of the storage

i is written

into

Thus, the first bit of the word

i adding

bits

is a binary

1/8 seconds

are written

back

to the repreinto the

read out.

will be negative.

0 to be written

causing

a binary

and supplied

as the first

bit of a data word,

Upon inversion

A positive

into the first

data bits are also binary

the first binary

is quite

signal.

i is read out the ET register

causes a binary

are made

read out of the ET register

the signal will be positive.

consecutive,

operation

input to the register,

from a binary

of the add circuit

negative,

amplifier

I as the first bit

When a binary

of circuits

of adding

a positive

With a negative

sentative

time

an open bit position.

of a data word

by the write-in

core number

of the elapsed

frcm the TR and TX registers

to the next bit position.

until the i reaches

register.

Their

and those

into the add circuit.

the i is carried

the add circuit

output

circuits.

for the ET consists

When the first bit

inverted

Both types

process,

in their logic programs.

of the word

bit position,

the output

circuits.

being

(the LSB)

of the counting

to an add circuit

of logic and switching

The add process

IN I

portion

register

difference

PROUEC--T-'G'-EM

signal

core.

l's, the output

by the write-in at the register

8-320 CON FIDENTIAL.

input

If the subsequent of the add circuit

l's to be %-ritten into the register.

0 in the data word from the register,

the

remains

Upon receipt

the output

of the add

of

CONFIDENTIAL

PROJ

s o.oo _.

circuit becomes positive, causing a binary i to be written back into the register for that bit position.

For example, if the first five bits of the word being read

out of the register are binary l's (representing a total of B 7/8 seconds of ET) and the next one is a binary O, then the first five bits of the new word will be binary O's; and the sixth will be a binary I. position represents and ET of four seconds.

A binary i in the sixth bit

The remaining bits of the data

word, again, are inserted back into the register Just as they were read out.

Although the circuitry of a subtract network is much the same as that of an add network, the operation is different because of the subtract logic.

If the

LSB of a word coming into a subtract network is a binary I, the output for that bit position will be negative, causing a binary O to be written back into register.

In this case, the 1/8 second has now been subtracted, and the balance

of the word will remain the same.

If the LSB of the incoming word is a binary 0

the output of the subtract network will become positive, allowing a binary i to be written into the register.

The output of the subtract circuitry will remain

positive until the first binary I enters the circuitry.

When this occurs, the

output becomes negative and causes a binary 0 to be written into the register. The rest of the word is then written back into the register Just as it came out. Data Transfer Binary words of time data are transferred into and out of the electronic timer by several different methods.

Data words received from the ground station, via

the DCS, are inserted directly into their respective storage registers in the timer.

Data from the guidance system computer, however, is transferred into the

buffer register of the timer and then shifted into the proper storage register.

8-321 CONFIDENTIAL

CONFIDENTIAL

PROJE-E-CTG

The

same process

computer:

is involved

a word

is shifted

and then transferred Instrumentation register storage

Timer

in the transfer

Data

is accomplished

to a pulse transformer. register

of data from the timer

out of its storage

to the computer.

System

EMINI

register

transfer

by shifting

The output

in the instrumentation

to the

into the buffer

from the timer

the desired

register

to the

data out of its

of the transformer

is coupled to a

System.

Interfaces

The following

is a list of the inputs and outputs

together

a brief

with

description

of the electronic

timer

of each:

INPUTS

(a)

A continuous at lift-off

(b)

28 vdc

to start the recording

A 28 volt emergency the electronic is not received crew-ground

signal from the spacecraft

start

timer

(c)

A Read,

rite co_uand

A _

to TR address

readout (e)

A _

and would

System.

timer

System

of TR _ud TX. to initiate

that the lift-off

signal

The signal would

be initiated

by actuation

be of

switch to UP. signal

the timer as to which (d)

in the event

from the Sequential

the event timer UP/DN

of ET and countdown

signal from the event

operation

co-ordinated

Sequential

from the digital

function

si_ual

computer

to direct

is to be accomplished.

from the digital

computer

to update

TTG to TR.

to T x address signal from the digital computer to enter

a TTGtoTx.

CONFIDENTIAL

or

CONFII)ENTIAL

PROJE

(f)

An elapsed time address signal from the digital computer to readout

(g)

ET.

Twenty-four clock pulses from the digital computer to accomplish data transfer.

(25 pulses for data transfer out of the electronic

timer.) (h)

Write data for update of TTG to TX, or TTG to Tx from the digital computer.

Twenty-four

data bits will be forwarded

serially,

LSB first. (1)

A TTG to TR ready signal from the DCS to command update of TTG to

(J)

A TTG to Tx ready signal from the DCS to co,and

entry of a TTG

to TX. (k)

Serial data from the DCS to update TTG to TR, or TTG to Tx. Twenty-four

data bits will be forwarded

Clocking is provided by the electronic

serially, LSB first. timer.

(1)

TTG to TR readout signals from the Instrumentation System.

(m)

An elapsed time readout signal from the Instrumentation

(n)

An AGE/count inhibit signal from ground based equipment, via the spacecraft umbilical,

to keep the elapsed time register

System.

at zero

time prior to launch. (o)

A clock hold signal from ground based equipment, via the spacecraft umbilical,

to prevent the timer from operating

prior to

launch. .

(p)

An event relay reset signal from ground based equipment, via the spacecraft

umbilical.

8- SeB CONFIDE_NTIAL

CONFIDENTIAL

PROJECT

(q)

GEMINI

An event relay check signal from ground based equipment, via the spacecraft

umbilical.

OUTPUTS (a)

A contact closure at TR for the digital computer.

(b)

A contact closure at TR (Continuous) for the Sequential System.

(c)

A contact closure at TX for the DCS.

(d)

Read data to the digital computer for ET or TTG to TR . Data bits are forwarded

serially, LSB first.

(e)

Signal power (12 +0 -1 volts) to the DCS and Instrumentation System.

(f)

Twenty-four clock pulses to the DCS to accomplish data transfer.

(g)

Twenty-four

clock pulses to the Instrumentation

System to accomp-

lish data transfer. (h)

Serial data to the Instrumentation System for readout of ET or TTG to TR.

(1)

Data bits are forwarded serially, LSB first.

A contact closure from TR-256 seconds to TR for the Sequential System.

(J)

A contact closure from TR-30 seconds to TR for the Sequential System.

(k)

An input power monitor signal to ground based equipment via the spacecraft umbilical.

TIME COPd_ELATION_UFFER

General The Time Correlation Buffer

(TCB) supplies the time correlation signals for the

blo-medical and voice tape recorder.

Serial data and data clock output from

8-324 CONFIDENTIAL

CONFIDENTIAL

PROJECT

GEMINI

the electronic timer is applied to the TCB input.

=

Serial data contains 24 elapsed

time words, and extra elapsed time word and a time-to-go to retrograde word.

The

TCB selects the extra elapsed time word end modifies the word format to make it compatible wlth the tape recorder frequency responses.

Information to the

recorder is updated once every 2.4 seconds and has the same resolution (1/8 second) as the electronic

timer.

Construction The dimensions of the TCB (Figure 8-84) are 2.77 x 3.75 x B.80 inches and the weight is approximately B.O pounds. eatable multivibrator, provides

The TCB contains magnetic shift registers, a i00 kc

a power supply and logic circuitry.

both input end output

One 19 pin connector

connections.

Operation The operation of the TCB is dependent on signals from the Instrumentation and the electronic timer. System, the electronic

System

In response to request pulses from the Instrumentation

timer provides

elapsed time and tlme-to-go

to retrograde

words to both the Instrumentation

System and the TCB.

The elapsed time word is

supplied every I00 milliseconds.

In addition, once every 2.4 seconds it provides

an extra elapsed time word and i00 milliseconds later it provides a tlme-to-go to retrograde word.

The TCB requires elapsed time information only, therefore, the tlme-to-go to retrograde word is rejected.

The tape recorders, due to their response times,

are not capable of recording time data every I00 milliseconds end for this reason only the extra elapsed time word is accepted by the TCB.

The remaining

24 elapsed time words and the time-to-go to retrograde word are rejected by logic

8-_ CONF|OENTIAL

CONFIDENTIAL

_oo

PROJECT

circuitry in the TCB.

GEMINI

Rejection of unused words is based on their time relation-

ship to other words.

The TCB contains three 8-bit magnetic shift registers in which the 24-bit extra elapsed time word is loaded once every 2.4 seconds. at the rate of one every i00 milliseconds. pulses from the electronic timer.

The TCB then shifts out bits

The shift rate is based on data clock

The first data clock pulse in a word causes the

TCB to shift out one blt of the data and the other 23 data clock pulses are disregarded.

Each bit that is shifted out of the shift register is stretched in time and coded to make it compatible wlth tape recorder response times.

The output to the bio-

medical recorder is one positive pulse for a binary O and two positive pulses for a binary i.

The most significant bit has two additional pulses to distinguish

it from the other 23 bits in the word.

Data is shifted out of the TCB in a least

significant bit first and most significant or marker bit last.

The output to the voice tape recorder is the same basic format as for the biomedical recorders.

However,

response characteristics into two pulses, doubling

to make it compatible wlth the higher frequency

of the voice tape recorder, each output pulse is chopped the frequency.

All input and output signals are coupled through complete

isolation

transformers

providing

DC isolation.

MISSION ELAPSED TIME DIGITAL CLOCK The mission elapsed time digital clock (used on spacecraft 6 through 12) is capable of counting time up to a maximum of 999 hours, 59 minutes and 59 seconds.

8-3 CONFIDENTIAL

The time

CONFiDENTiAL

PROJECT

GEMI

I

is displayed on a decimal display indicator on the face of the unit.

The seconds

tumbler of the display is further graduated in 0.2 second increments. may be started or stopped manually.

Counting

Prior to initiating a counting operation,

the indicator should be electrically present to the desired starting time which i normally starts from zero at llft-off and counts mission elapsed time in real time.

Construction The dimensions of the digital clock are approximately 2 inches by 4 inches by 6 inches and its weight is approximately 2 pounds.

Onithe face of the clock

there are two controls and a decimal displaywlndow.

The unit contains four

electronic modules, a relay and a step servo motor.

Aigear train connects the

servo motor with the decimal display tumblers.

An electrical connector is

provided at the rear of the unit for power and signal inputs.

Operation Operation of the digital clock is dependent on timing pulses from the electronic timer.

The time base used for normal counting operations in the digital clock

is derive_ from the 8 pps t_m_ng pulse output of the electronic timer.

The

8 pps signal is buffered and used to establish the repetition rate of a step servo motor. tumblers.

The step servo motor is coupled through a gear train to display

Additional counting rates are selectable fo_! the purpose of setting

the clock to a desired starting point.

Start/Stop Operation _

Remote starting of the digital clock is accomplished h_ providing the 8 pps timing pulses from the electronic timer.

Before remote starting can be accom-

plished, the START/STOP switch must be in the START positlon and the DEC_/INCR

8- 7 CONFIDENTIAL

CONFIDENTIAL

__oo

PROJEMINI

switch must be in the 0 position. accomplished

(if timing

pulses

in the START position. latching

relay.

circuitry, removing

the

the time base

in the STOP position,

Counting

starting

are available)

This energizes

The relay

allowing

Manual

applies

counting

control

operation

voltage

clock

can be

the START/STOP

switch

side of the start/stop

and operating to begin.

(8 pps) from the clock removing

of the digital

by placing

the start

....

voltages

Counting

or by placing

and disabling

the

magnetic

to the

counting

may be stopped

the START/STOP

by

switch

circuitry.

Operations

When the start/stop

relays

are actuated

and operating

applied to the servo motor,

a plus 12 volt

count

the counting

gate.

This

and 8 pps t4mlng

initiates

signal which

dc enable

sequence.

is buffered

voltage signal

The

and supplied

of plus 28 volts

is applied

electronic

dc

to the normal

timer

provides

to the sequential

logic

section.

Sequential

logic

section

necessary

sequences

direction

of the other

consists

of output

of four set-reset

signals

(set output

pulse,

flop switches

remains

sequence resetting third

with

the preceding

one subsequently

condition

reset.

alternate one. reset,

and the sequence

timing

After

leaving pulses

the fourth

the first

is started

Then,

when

only

over again.

8-328

the

three of

and one is

of the first timing The first one also another

timing

switched

pulse

one set.

one flip flop,

flip flop has been

one is again

CONFIDENTIAL.

begins,

the second

setting

provide

to step in one

positive)

With receipt

to the set condition.

the first flip flop resets,

continues

process

(reset output

positive).

set, but the other two remain

is received,

As the counting

condition

in the set condition the next flip

to cause the servomotor

(Figure 8-91 ).

the flip flops are in the reset

flip flops which

The

then

set and the

to the set

In order to have the logic

CONFIDENTIAL

sEoR 300 _ -_'_

PROJECT

.,

-_T--_--_

GEMiNi

BUFFER

--

I

__

CONTROL SECTION I

CLOCK

FUNCTION

l

I

]

o

OSCILLATOR

Z U

OPERATING VOLTAGES

CONTROL

CONIROL

PANEL

UPDATE "FWD"

"FORWARD"

CONTROL

CONTROL l

Z

0

CONTROL

SEQUENTIAL LOGIC SECTION

l

_

0 Z$

I

CONVERSION AND DRIVER SECTION 2J I 8PPS

B

J •

2 REMOTE STOP (TEST USE ONLY)

E I

÷28V DC

D

8PPS RETURN

C

"



+28V

I

r--o--

POWERGND CHASSIS GND

F H

_

__ --1,,,,

+12V

_

---

__ o ? C_

I

I •

-

O

_

+28V

J I

i

Figure

8-91

Mission

Elapsed

Time

Digital

8-329 CONFIDENTIAL

Clock

Functional

Diagram

CONFIDENTIAL

PROJECT

GEMINI

section function properly, either a forward or reverse control signal must be received from the start/stop relay.

These are used as steering signals for the

t_mlng pulses which set and reset the flip flops.

For counting up, the control

signals cause the flip flop operating sequence to be in one direction.

When

counting down, they cause the sequence to reverse;

flip flop number _ is set

first, then number 3, etc., back through number 1.

The output of the sequential

logic circuit is applied to the power converison and driver section.

The power conversion

and driver section converts the voltage-pulse

outputs of the

logic section to current pulses which are used to drive the servomotor. driver section provides four separate channels, one for each input. has a logic gate and a power driver.

The

Each channel

The logic gate permits the logic section

output to be sensed at ten selected times each second.

The gate senses only the

occurence of a positive signal which will allow the power driver to conduct and send a pulse of current through one of the four se_vomotor stator windings.

The sequence of pulses from the driver section causes the servomotor to step eight times each second and 45° each step.

Figure 8-92 illustrates the step

positions relative to the sequence of operating pulses from the driver section. If pulses were applied to each of the four servomotor windings, without overlap, the unit would step 90° each repetition.

It is this overlapping of signal

applications which causes it to step 45° at a time.

The display indicator is a rotating

counter with wheels to display seconds, tens

of seconds, minutes, and tens of minutes, hours, tens of hours and hundreds of hours'

It is coupled to the servomotor through a gear train with a reduction

ratio, from the servomotor, of I0:i.

Therefore, as the servomotor rotates 360°

8-33o CONFIDENTIAL

-

CONFiDENTiAL SEDR 300

,j+,--.

/

PROJECT

GEMINI

P8 o

P7 •

"

P1

PERMANENT _2BV

S;

P6"

ROTG2R

(

i

PER_

P2

_NT/"

1

P

Ti P'CAL) 3

NoTE (I)

PI-P8 ARE ROTOR POSITIONS $4

$6

OPERATION

RESULT

GROUNDSI, GROUNDS6 OPEN $I GROUND $3 OPEN $6 GROUND $4 OPEN$3 GROUND SI OPEN $4 GROUNDS6 OPEN $6 GROUND $4 OPEN SI GROUND $3 OPEN $4 GROUND $6 OPEN $3 GROUND $I

ROTOR INDEXES TO ARBITRARy REF. POSITION ROTORSTEPS 45° C.W. (P2) ROTOR STEPS 45 ° C.W. (P3) ROTOR STEPS 45 ° C.W. (P4) ROTOR STEPS 45 ° C.W. (PS) ROTORSTEPS 45° C.W. (P6) ROTOR STEPS 45 ° C.W. (P7) ROTOR STEPS 45 ° C.W. (PS) ROTORRETURNSTO REF. POSITION (PI) ROTOR STEPS 45 ° C.C.W. (PE) ROTOR STEPS 45 = C.C.W. (P7) ROTOR STEPS 45 ° C.C.W. (P6) ROTOR STEPS 45 ° C.C.W. (FS) ROTOR STEPS 45 ° C.C,W, (P4) ROTOR STEPS 45 ° C.C.W. (P3) ROTOR STEPS 45 ° C.C.W, (P2) ROTOR RETURNS TO REF. POSITION (PI)

Figure 8-92 Step Servomotor Operation 8-331 CONFIDENTIAL

(PI)

CONFIDENTIAL SEDR300

PROJ EC--C"T-'GEMINI (in one second), the indicator shaft turns 36° or 1/8 of a rotation.

Since the

seconds wheel is directly coupled to the shaft and is calibrated from zero to nine, a new decimal is displayed each second.

As the seconds wheel moves from

nine to zero, the tens-of-seconds wheel moves to the one position.

The operations

of the other wheels are similar.

Updating The display may be returned to zero or updated to some other readout with the use of the DECR-INCR rotary switch on the face of the timer.

The rotary switch must

be in the 0 position in order to have the timer operate at a normal rate; with the switch in one of the other position, it counts at a different rate.

There are

three rate selections, each for the INCR and DECR (count-up and count-down) Ulxlating modes.

The positions on each side that are farthest from the 0 position are

utilized to make the timer count at 25 times its normal rate.

The next closer

positions are utilized to count at three times the normal rate.

The positions

nearest the 0 position are used to count at a rate 0.B times the normal one. This position

serves to more accurately

place the indicator at a desired readout.

Operationally, positioning the rotary switch in some position other than 0 causes the time base frequency from the electronic timer to be replaced in the circuitry by an update oscillator.

The frequency of the oscillator

is established by the

position of the rotary switch.

In the 25X positions, the frequency is 400 cycles

per second; in the 3Xposition,

it is 48 cps; and in the 0.3Xpositions,

approximately not critical

4.8 cycles per second. since the oscillator

it is

The accuracy of the oscillator output is

functions

only for updating

8-332 CONFIDENTIAL

purposes.

_

CONFIDENTIAL

PROJE

__.

SEDR 300

:

Operation of rotary switch supplies a stop co_-nd

____

to the electronic circuitry,

and stsrt switch must be operated to resume normal count. EVENT TIMER

General The event timer is capable of counting time, either up or down, to a ,_xlmum of 59 minutes and 59 seconds.

The time is capable of counting time down

to zero

from any preselected time, up to the maximum listed above.

NOTE When the event timer is counting down_ it will continue through zero if not manually stopped. After counting

through

zero,

the

timer will be1 gln counting down from 59 minutes and 59 seconds.

The time is displayed on a decimal display indicator Qn the face of the unit. The seconds tumbler of the display indicator Is further graduated in 0.2 second increments.

Counting, In either direction, may be started or stopped either

remotely or manually.

Prior to starting a counting operation, the indicator must I ;

be manually preset to the time from which it is deslr_d to start counting. Construction The dimensions of the event time are approximately 2 X 4 x 6 inches and the weight about two pounds.

On the face of the timer, there are two toggle switches, one i rotary switch, and a decimal display window. (Refer to Figure 8-84) In addition

to the panel-mounted controls, the unit contains four ielectronlcmodules, two relays, a tuning fork resonator, and a step servo motor. i

8-3S3 CONFIDENTIAL

A gear train connects

CONFIDENTIAL $EDR 300

the servo motor connector

with the decimal

display

tumblers.

There

is one electrical

on the back of the unit.

O e tion The operation to Figure

of the event timer

8-93)

It provides

tion of the decimal operation

display

is developed

when

a series of toggle-type

to the display

to rapidly

reset

Start/Stop

Operations

mechanism. the output

tumblers.

the same manner.

signals.

to zero or to some other

The difference

In order to initiate

counting

sary to first have the STOP-STBY off position.

counting

(Refer to Figure

switch

the repi-

through

rates may be selected desired

a gear in order

indication.

are accomplished

in almost

by either

in either

method,

it is neces-

the STHY or the center

8-8_)

NOTE When

starting

switch

- STBY

before

Manual

starting

with

in the center position,

incurred. STOP

is accomplished

To prevent

any

starting

inaccuracy

inaccuracies,

is the

in the STBY position

the timer.

may then be accomplished

either the UP or the DN position.

the STOP - STBY

a small

starting

switch is placed

by placing

This energizes

8-B CONFIDENTIAL

to

in the source of the control

operations

toggle

the opera-

is connected

is coupled,

of the timer is only

(Refer

counting

signal establishes

The servo motor

functions

for normal

for, resonator

The resulting

Additional

The remote and _manual start/stop exactly

of a tuning

timer.

is used to control

The time base used

servo motor.

the timer

of the electronic

its own time base which

flip flops.

tion rate of a stop-type train,

is independent

the UP-DN

toggle

switch

in

one of the two coils of the

CONFIDENTIAL

PROJECT j

FREQUENCY

GEMINI

STANDARD

COUNTDOWN

STAGES

SECTION

STAGES

:

I

I

L__

J

TUN,NGFO I UP KI ATE ' EVERS S OU

RESONATOR i

OSCILLATOR

OPERATINGVOLTAGE. _

RATECONTROL

"FORWARD"

SECTION

]

J

UPDATE"REV" CONTROL

=

I

I

iPDAT_"_D" CONTROL

CONTROL PANEL

POWERCONT. AND DRIVERSECTION I

j

COUNTDOWN HOLD

_oP

LMANUAL FORWARD MANUAL REVERSE

F

I

2jL

--

REMOTESTOP+28V

j_

45"

o j J

O

REMOTEFORWARD+28V REMOTEREVERSE +28V

I_1

L

___

I

+28v

I I

__

.

Figure

I 36=,/SEC'

_

8-93

Event

Timer

Functional

8-335 CONFIDENTIAL

_

Diagram

MIN.

SEC.

CONFIDENTIAL

PROJ

EC=r ' GEMINI

forward/reverse relay, also causing the start coil of the start/stop relay to be energized.

When these events take place, control and operating voltages are supplied

to the counting circuitry, thus allowing the operation to begin. to be accomplished

When starting is

remotely, either a remote forward or a remote reverse signal Is

transmitted from the ground station to energize the forward/reverse relay.

The

counting process may be stopped upon receipt of a remote stop signal or by placing the STOP-STBY

switch in the STOP position.

Either

of these functions energizes

the stop side of the start/stop relay, removing critical operating voltages from the counting

Countin_

circuitry.

Onerations

Normal counting operations begin with the actuation of the forward/reverse relay in either direction and the start/stop relay in the start direction.

When the forward/

reverse and the start/stop relays are actuated, an operating voltage of +28 vdc is applied to the servo motor and a ground level inhibit signal is removed from the toggle flip flops.

Also, a +12 vdc control signal, denoting either a forward or

reverse counting process, is transmitted to the logic circuitry preceding the servo motor.

The remainder of the timer circuitry has operating voltages applied when

the STOP/STBY switch is placed in STBY.

With the application of operating voltages, the tuning fork resonator emits and ac signal of 1280 cycles per second.

The signal is passed through a buffer to condl _

tion it for use by the series of seven toggle flip flops in the frequency standard countdown section.

Since the output frequency of each fllp flop is half that of Its

input, the final one in the series generates a signal of ten pulses per second.

The

outputs of the countdown section are connected to the sequential logic section and the power conversion

and d_iver section.

8-SS6 CONFIDENTIAL

CONFIDENTIAL.

PROJECT

Sequential

logic

necessary

section

sequences

tion or the other

consists

of output

(set output

flip flop switches other two remain fllp

alternate After

timing

leaving pulses

the fourth flip

first one Is again _-_

switched

In order to have

reverse

control

signals

The power logic driver

When

conversion

section

to current

section

section

of a positive

send a pulse

of current

four

is received, sequence

resetting

the next

set, but the the first

continues

with

the preceding

one.

down,

which

separate

function

properly,

pulses which

either

operating

the sequence

3, etc., back through

converts

are used

a forward

relay.

s_t and reset

the flip flop

they cause

section

one subsequently reset, the i and the sequence is started over

These

are

the flip

flops.

sequence

to be

to reverse: number

the voltage-pulse

or

flip

1.

outputs

to drive the servo motor.

of the The

one for each input. Each channel i has a logic gate and a power driver. The logic gate permits the logic section ! output to be sensed at ten selected times each second, i The gate senses only the occurrence

provides

pulses

pulse,

remains

from the forwmrd/reverse

cause

then number

and driver

and one is in the set

set and the third

signals

counting

The

flip flop, then

for the timing

_ is set first,

one set.

to the set condition

the logic

up, the control

in one direction. flop number

one

signal must be received

as steering

For counting

setting

flop has been

again.

used

only the second

pulse

the

three of the flip

of the first timing

timing

provide

to step in one direc-

procelss begins,

The first on_ also

when another

which

the servo motor

With receipt

to the set condition. Then,

flip flops

(reset output positive)

positive).

reset.

flop resets,

to cause

As the counting

flops are in the reset condition condition

of four set-reset

signals

(Figure 8-93).

GEMI

signal which through

channels,

will

allow

the power

one of the four servo

8- 337 CONFIDENTIAL

motor

driver

to conduct

stator windings.

and

CONFIDENTIAL

PROdGEMINI

The

sequence

of

pulses

from

the

_river

times each second and 45° each step.

section

causes

the

servomotor

to

step

ten

Figure 8-92 illustrates the step positions

relative to the sequence of operating pulses from the driver section.

If pulses

were applied to each of the four servomotor windings, without overlap, the unit would step 90° each repetition.

It is this overlapping of signal applications

which causes it to step 45° at a time.

The display indicator is a rotating counter with wheels to display seconds, tens of seconds, minutes, and tens of minutes.

It is coupled to the servomotor through

a gear train with a reduction ratio, from the servomotor, of 12.5:1.

Therefore,

as the servomotor rotates _50° (in one seconds), the indicator shaft turns 36° or i/i0 of a rotation.

Since the seconds wheel is directly coupled to the shaft

and is calibrated from zero to nine, a new decimal is displayed each second.

As

the seconds wheel from nine to zero, the tens-of-seconds wheel moves to the one position.

The operations of the other wheels are similar.

U_datin_ The display may he returned to zero or updated to some other readout with the use of the DECR-INCR rotary switch on the face of the timer.

The rotary switch must

he in the 0 position in order to have the timer operate at a normal rate; with the switch in one of the other positions, it counts at a different rate.

There

are three rate selections, each, for the INCR and DECR (count-up and countdown) updating modes.

The positions on each side that are farthest from the 0

position are utilized to make the timer count at 25 times its normal rate. The next closer positions are utilized to count at four times the normal rate. The position near_%

"'he0 position are used to count at a rate 0._ t_mes the

8-338 CONFIDENTIAL

_i

CONFIDENTIAL

the normal

one.

at a desired

This

position

serves to more accurately

place

the indicator

readout.

Operationally,

positioning

the rotary

switch

in some position

other

than

0

i

causes the tuning replaced

fork resonator

in the circuitry

osc_11Rtor

is established

positions,

the frequency

and the first

by an update

cycles

6_0 cps; and in the 0.4X positions, The accuracy tions

ACCUTRON

The clock

with

The frequency

of the rotary per second;

to be

of the

switch.

In the 25X

in the 4X position,

it is approximately

output

flip flops

64 cycles per

is not critical since

it is

second.

the oscillator

func-

purposes.

clock (Figure

is approximately

has a 24 hour

dial with

and a sweep second

of day.

toggle

CLOCK

The Accutron

hand

of the oscillator

only for updating

oscillator.

by the position is 4,000

three

The unit

major

divisions

on the co_,and

square

is capable

The

An hour hand,

indication

panel. clock minute

of the time

and has no electrical

of operating

mercury

control

and on e inch thick.

for a precise

self contained

on the internal

pilot's

on the half hour.

hand are provided

The clock

one year

located

2 3/8 inches

is completely

the spacecraft.

approximately

8-84),

continuously

interface for

battery.

Operation The Accutron

clock is provided

set and start the timer From

the depressed

clock will

with

as desired.

position,

start automatically

one control

knob.

The knob

To stop the timer,

the clock

is used

the control

can be set to the desired

when the control

8-339 CONFIDENTIAL

knob

is released.

to stop,

is depressed.

time.

The

CONFIDENTIAL

PROJEC--T-"GEMINI

The Accutron clock is a highly accurate device with an error of less than + 3 seconds per day.

This high degree of accuracy is made possible by using a tuning

fork as the time standard, instead of the conventional balance wheel and hair spring.

The tuning fork is magnetically driven at a natural frequency of 360 cps.

The tuning fork frequency is adjustable, ma_ing precise calibration of the clock possible.

The vibrational motion of the tuning fork is converted to rotational

motion to provide outputs of:

one revolution per day, one revolution per hour

and one revolution per _luute, for the clock hands.

_CHANXCAL

CLOCK

Construction The mechanical clock is shown in Figure 8-84. x 2 _4

x 3 _4

The unlt is approximately 2 1/4

inches and weighs about one pound.

increments of 0-24 and 0-60.

The dial face is calibrated in

The clock has two hands for the time of day portion

and two for the stopwatch portion.

The controls for operating both portions of

the clock are located on the face of the unit.

O_eration The clock is a mechanical device which is self-powered and required no outside inputs. minutes.

The hand and dial-face clock displays Greenwich Mean Time in hours and A control on the face provides for winding and setting the unit.

With

the passing of each 24-hour period, the calendar date indicator advances to the next consecutive number.

The stopwatch portion of the clock can be started,

stopped, and returned to zero at any time.

Two settable markers are provided on

the minute dial to provide a time memory, permitting the clock to serve as a --\

short-term back-up timer.

CONFIDENTIAL

CONF|DENTIAL.

PROPULSION

SYSTEMS

TABLE OF CONTENTS TITLE

_

PAGE

GENERAL INFORMATION ........ ORBIT ATTITUDE AND HANEUVERING SYSTEM,el. ...e.eee. SYSTEH DESCRIPTION: . ...... SYSTEM OPERATION..... ..... SYSTEM UNITS. . ...... RE-ENTRY CONTROL SYSTEM........ SYSTEM DESCRIPTION.... .... SYSTEM OPERATION ..ooeooQeeO SYSTEM UNITS eQeoeeeeeeeee

8-341 GONFIDENTIAL

. .

. . . . • , . i

.

8-343 8-343 8-343 8-349 8"352 8-369 8-369 8-374

8 376

CONFIDENTIAL

_,- "

PROJECT

GEMINI

SEDR3OO

._T _

___S

__

RI_E'_USUL_R_OR

°E__j

ORBIT ATT,TUDE MANUEVER,NG

_.¢KA_E

!QQ P',_=-' UP

e®'T 'DO N II

"A"PACKAOE

I Q Q ROLL CLOCKWISE I

"D" PACKAGE

O

"B" PACKAGE

vO_v_ZER S"UOF

SYSTEM km

Q

YAWLEFT

_@ _OLL¢OUNTE_¢LO I LEJ_) _ANS_TEAFT _NS_TE PORWARD ®® I

/_

,C°ONL ® TRANS ITEDOW OXIDIZER

TANK

(S/C 6, 8 & UP) OXIDIZER

TANK

(S/C 50NLY)_

(s/c 8&uP) FUEL TANK (S/C 8 & UP)

CUTTER/' SEALERS OXIDIZER

TANK

(s/c 6,8&9) FUEL TANK

, I (S/i0

t

8, UP)_

(s/c6, 8&uP) {S/C 5 ONLY) (2 REQ'D)

I

EQUIPMENT SECTION

_

.CABIN

RETRO SECTION

Figure

8-94

Orbit

Attitude

SEETI

Maneuvering 8-842 CONFIDENTIAL

System

and

".

'I'CA

Location

OONPIOMNTIAL

___

SEDR300

,

PROPULSIONSYSTEM @_RAL

INF0_ATION

The Gemini

Sl_cecraft

capability. spacecraft

is provided

(Figure mission,

8-94).

systems, Control

System

the time phase

of launch

vehicle

the re-entry

cal c_u_ands automatic

ORBIT ATTIT_ SY_

control

attitude

separation

during

separation

is accomplished

System

(OA_)

phase

and provides

until

The RCS provides

the entire

until

the re-

by two rocket

engine

and the l_-entry

Control

maneuver

the initiation

attitude

of the mission.

from the Attitude

mode

vehicle

and Maneuvering

the spacecraft

of the mission.

during

is used

control

(RCS).

The OAMS controls f-

and maneuvering

capability

of launch

Spacecraft

the Orbit Attitude

an attitude

This control

from the time

entry phase is completed.

with

control

capability

of the retrograde for the re-entry

The 0AMS and RCS respond

Maneuvering

or from the crew in the manual

from

Electronics

module

to electri-

(ACME)

in the

is a fixed

thrust,

mode.

AND __

DESCRXPTXON

The Orbit Attitude

Maneuvering

cold gas pressurized, propulsion

system_

System

storable

which

is

liquid,

capable

of

(OAMS)

(Figure

hypergolic operating

8-94)

hi-propellant, in

the

environment

self cont_Line_ outside

the

i

earth's

ataosphere.

chamber

assemblies

Maneuvering (TCA) singly

capability

is obtained

or in groups.

by firing

The thrust

chamber

thrust assemblies

!

are mounted modes

at various

of rotational

points

about

or translation

the adapter acceleration

8 -343 OONFIDMN'rlAI.

in locations required.

consistent

with

the

j

CONFIDENTIAL SEDR 300

:_.

COMMAND PILOT INSTRUMENT PANEL

PEDESTAL INSTRUMENT

INSTRUMENT

'_'z/

PANEL

PANEL

CENTER CONSOLE

FUEL TANK

PACKAGE t

"D"

FUEL SUPPLY SHUT OFF/ON _

VALVE

FUEL TANK S/C8&UP

THRUST CHAMBER (TYP 16 pLACES)

RESERVE

"_

HEATER

,_F ,, S/C 8 & UP "

S/C 5 & 6

OXIDIZER SUPPLY

PRESSURE---"

'RESSU_NT S_O_GB

"A" PACKAGE

_-

SHUT

"E .... I-h B" '_" o:,ON PACKAGE CKAGE PAC_GE

--

OVERHE.a SW & CIRCUIT BREAKER PANEL

T-TEMPERATURE SENSOR P-PRESSURETRANSDUCER M'_MOTOR V-PYROTECHNIC

OVERHEAD SW & CIRCUIT BREAKER PANEL

OXIDIZER NK

VALVE LEGEND INSTRUMENT

PANEL

-\

CENTER CONSOLE

Figure

8-95

j

OAMS

Control

& Indicator

8-344 CONFIDENTIAL

Schematic

CONFIOIENTIAL

SEDR300

The

OAMS provides

a means

control

axes

(roll,

(right,

left,

up,

translational

pitch, down,

space

vehicle

The primary

purpose

used, after

firing

during

the

yaw)

and

forward

and

aft).

creates in

the

charges,

launch

During

spacecraft

(except with

are mounted

The

on a structural

several

functioning

of

three

in

cumbina%ion

feed

of forged

lines

in retro

of

attitude

six

directions

attitude

rendezvous

and

in orbit.

and docking

with

(module

tubing

late

Spacecraft

(RCS).

adapter.

in _he equipment

All

from the

control

OAMS control

Each

in

cutter/sealer

are separated

"packages"

and filters.

occur

from the equipment

concept)

and welded

from the launch

may

sequence,

section)

System

The OAMS is also

the Spacecraft

of the adapter.

Control

frame

components

control

of retrograde

section

by the Re-entry

units consist

control

to separate

six TCA's located

control

its

or in case of an abort which

initiation

the equipment

are then assumed

translation

of OAMS is spacecraft

a normal

about

capability

sever and seal the propellant

of the OAMS

spacecraft

orbit.

of shaped

the launch phase. devices

rotating

and

maneuvering

another

vehicle

of

functions

_,nlts and tan_ section.

package

consists

The of

The OAMS iControl and Indicator i i

Schematic

(Figure

controls which are provided delivery

8-95) is a simplified

are directly

by the Attitude

of pressurant,

tubing

manifold

system.

group,

fuel/oxidizer

related

schematic

of the indicators

to the Propulsion

Control

and Maneuvering

fuel and oxidizer The OAMS system

group and Thrust

System. Electronics

is accomplished is divided

Chamber

and manual

Additional

(ACME) System

by a uniquely

into three

controls

groups;

brazed pressurant

Assambly i (TCA) group.

Pre.srarant Group f

The pressurantgroup (Figure 8-96) consists of a pressuranttank, "A" package,

CON_IDINTIAL

The

j

CONFIDENTIAL SEDR300

_..

PROJECT

GEMINI

PURGE

TESTVALVE

CHARGING

VALVE FUEL TANK

_,

_(ONE TANK ON TWO TANKS Orl S/C 6, 8 & 9. THREETANKS _ ON S/C 10 aUP.)

HIGHPRESSURE HIGHPRESSURE _

_

_,_ i'_

_ (S/C 8 & UP)

_

_

_ _h'_:

_

I l I I

"F" PACKAGE

RESERVE FUEL TANK

LEGEND .'.'.'.'.'.'.'.'."

PRESSURANT

k'_'_'k'_k'k_k_

FUEL

(S/C 8 & UP)

I

.'-'.'-'.'.'-.'-.'.'.•• .'-" OXIDIZER NORMALLY

CLOSED

PYROTECHNIC VALVE



JlBId

SOURCE _ _" PRESSURE

PACKAGE

FUEL TANK VENT VALVE

PRESSURE TRANSDUCER

'

BURST

REGULATED PRESSURE TRANSDUCER

DIAPHRAGM RELIEF CHECK VALVE

NORMALLY OPEN PYROTECHNIC VALVE

FILTERS "E" PACKAGE

FILTER CHECK VALVE

MANUAL BYPASS VALVE

BURST DIAPHRAGB

FILTERS

TWO WAY SOLENOID

CHECK

VALVE

VALVE

VALVE

I

OVERBOARD RELIER VALVE TEST PORTS

NORMALLY CLOSED PYROTECHNIC VALVE

OXIDIZER VENT VALVE SWITCH VALVE

TEST

JLATOR

E

OUT TEST

_GASUTR_i_

.......................

NORMALLY CLOSED PYROTECHNIC VALVE

;_

NOTE [_

Figure

8-96

Orbit

Attitude

ADDITIONAL

Maneuvering 8-346 CONFIDENTIAL

TANKS ARE CONNECTED

System

Schematic

PURGE FTORT

_..............................................,.. IN PARALLEL.

(Sheet

1 of 2)

i

CONFIDENTIAL SEDR 300

: _.

___¢_)'

PROJECT

GEMINI

__

"D" PACKAGE FUEL CHARGINGF_

_-

PY'ROEECHNIC VALVE

I LX

FUEL TEST VALVE

RX

VALVE _]ENO,_L_CLOSE D; P_F_/D

PROPELLANT FUEL SUPPLY SHUTOFF VALVE

LINE CUTTER/ SEALER

__.;.;__.___._._._.___._`_`___._._._._`_.___._.__:._._._._._._.___._._.:`:__.___._._`_'_._._`_ :.:.:.:.:

Figure 8-96 Orbit Attitude

Maneuvering 8-347 CONFIDENTIAL

System

Schematic

(Sheet 2 of 2)

CONFIDENTIAL

"E" tseks_e, package.

"F" package Inlet

valves,

on Spacecraft ports

and test

8 thru ports

12, are

pressure

permit servicing, venting, purging and testing.

provided

regulator, at

and "B"

accessible

points

to

Filters are provided throughout

the system to prevent cQntam4nation of the system.

The pressurant is isolated

in the storage ta-_ dur_nS pro-launch periods by a normally closed pyrotechnic actuated valve, located in the "A" package.

On Spacecraft 8 thru 12, the pressurant

is isolated from the reserve fuel tank by the "F" package.

l_el/Oxidizer Group The fuel/oxidizer (propellant) group (Figure 8-96)

consists of expulsion bladder

storage tanks, "C" and "D" packages and two propellant shut off valves.

Charging

valves and ports and test valves and ports are provided at accessible points to permit servicing, venting, purging and testing.

The propellants are isolated in

the storage tanks by normally closed, pyrotechnic actuated valves ("C" and "D" packages).

Filters are provided in the "C" and "D" packages, down stream of the

isolation valves, to guard against contamination of the thrust chamber assemblies. The propellants used are: OXIDIZER - nitrogen tetroxide (N20_ conforming to specification MIL - P - 26539 A FUEL

- monomethyl hydrazine (N2H3CH3) conforming to specification MIL - P - 27_O_

Thrust Chamber Assembl_ (TCA) Group The TCA group consists of thrust chambers and electrical solenoid valves. teen TCA's are used per spacecraft (Figure 8-9_).

Eight twenty-five pound thrust

capacity TCA's are used for attitude control, (roll, pitch and yaw).

8-3_8 CONFIDENTIAl.

Six-

Six one-

f_

CONFIDENTIAL

hundred pound and two eight-five pound thrust capacity TCA's are used for translational maneuvering.

SYST_

OPERATION

Pressurant

Group

The pressurant tank contains high pressure helium (He)istored at 3000 PSI. (Figure 8-96).

The tank is serviced through the "A" p_ckage high pressure gas

charging port.

Pressure frcm the pressurant tan_ is isolated from the remainder

of the system by a normally closed pyrotechnic actuated isolation valve located in the "A" package.

Upon command, the system isolation valve is opened and

pressurized helium flows through the "E" package, to the pressure regulator, "B" i i

f_

package and propellant tanks.

Normally, pressurant is!controlled through system

pressure regulator, and regulated pressure flows to the "B" package.

The "B"

package serves to deliver pressurant at regulated pressure to the fuel and oxidizer i

tanks, imposing pressure on the propellant tank bladder exteriors.

Relief valves

in the "B" package prevent over pressurization of the System downstream of the regulator.

Burst diaphragms are provided in series with the relief valves, in

the "B" package, to provide a positive leak tight seal between i

system pressure

and the relief valve.

The "E" package provides a secondary mode of pressure regulation in the event of regulator failure.

In the event of regulator over-preSsure failure, resulting in

excess pressure passage through the regulator, a pressure switch ("E" package) intervenes and automatically closes the normally open qartridge valve. I _

pressure

is

then

controlled

manually

by the

crew by momentary

OONPIOBNllAI.

placing

Regulated the

OAMS-

CONFIDENTIAL

PMINI SEDR 300

R_G

switch in the _

is obtained

position.

from the "B" package

and 6, the "F" package regulator

switch to S_. normally

This

open valve,

is then regulated mation

obtained

selection

ulated

a division

(Figure

In the event of regulator the required

flow of propellant affords

a safety

tank bladders.

through

sure returns

On spacecraft package. placing

vapors

transducer pressure

in the system.

into the pressurant for prevention

would

first rupture

the relief valves.

The relief

The reg-

a signal to the

of the regulator, to manually prevent

The "B" package

hack

also

on the fuel and oxidizer

downstream

diaphragms,

valves will

The "B"

tanks.

check valves

of over pressure

infor-

on spacecraft

8 thru 12.

the reading

system.

Pressure

pressure

transducer

downstream

Three

the burst

and closes the

and provides

the crew utilizes

Should

completely.

control

on spacecraft

Should the system be over pressureized

of the regulator

then he vented

reset

when

over-

system pres-

to normal.

8 thru 12, the pressurant

The normally the 0AMS RESV

pressurant

pressure

5

select the OAMS-REG

flow to the propellant

8-95) indicating

pressure

feature

the over pressure hoard

transducer

12.

closed valve

the regulator

regulated

of pressurant

failure,

8 thru

by the crew with

is sensed by the pressure

_ahin • instrument,

maintain

the normally

information

on spacecraft

the crew can manually

(OAMS-PULSE)

pressure

pressure

transducer

on spacecraft

by-passes

from the "B" package

provides pressure

opens

thus pressurant

5 and 6, the "F" package package

occur,

Control

pressure

transducer

failure

manually

8-95).

re_ulated

pressure

under-pressure

(Figure

flows

closed pyrotechnic switch

(Figure

to flow to the reserve

8-95)

from the "B" package

valve

in the "F" package

in the SQUIB

fuel tank .....

8-350 CONFIDENTIAL

to the "F" is opened by

position, allowing

r.

CONFIDENTIAL

PROJECT

GEMI141

Fuel/Oxidizer Group Fuel and oxidizer are stored in their respective tank: and are isolated from the remainder of the system by normally closed pyrotechni_ valves in the "C" (oxidizer) and "D" (fuel) packages.

Upon command, the "A" (presSurant), "C" and "D" package

isolation valves are opened.

The pressurant imposes

)ressure on the propellant

tank bladders and fuel and oxidizer are distributed through their separate tubing manifold systems to the _,let of the thrust chamber solenoid valves.

Upon c_and

on spacecraft 8 thru 12, the normally closed pyrotechnic valve in the "F" package is opened to allow pressurant to impose pressure on the reserve fuel tank bladder to distribute reserve fuel to the thrust chamber solenoid valve. i

Two electrically

operated motor control valves (Figure 8-95) are located in the propellant feed !_nes, upstream of the TCS's.

In the event of fuel or oxicizer leakage through

the TCA solenoid valves, the motor operated valves can be closed by the crew to prevent loss of propellants.

The valves can again be iactuated open by the crew,

when required, to deliver propellants to TCA solenoids.

Th_rust

Chamber Assembly

(TCA) Group

Upon co_and

from the autQmatic or manual controls, signals are transmitted ! through the Attitude Control Maneuvering Electronics (ACME) to selected TCA's to i

open simultaneously the normally closed, quick-acting ifuel and oxidizer solenoid

i valves mounted on each TCA. rected through _11

In response to these commands, propellants are di-

injector Jets into the combustio_ chamber.

The controlled

l fuel and oxidizer impinge on one another, where they ignite hypergollcally to burn and create thrust.

Heaters are connected to each TCA oxidizer solenoid valve i

to prevent freeze-up and are activated by an OAMS RTRS switch (Figure 8-95).

8-351

CONIIIDENTIAL

CONFIDENTIAL

PROJECT

GEMINI

SEDR 300

S1rS_ UNZTS

Pressurant

Stor86e

The helium

pressurant

is

16.20

inches

The helium

Tank is

outside

stored

in

diameter

welded,

and

has

actuated

valve.

spherical

an internal

gas is stored at 3000 psi rand held

closed pyrotechnic

volume

therein

The pressurized

fuel and oxidizer

from their respective

to the pressurant

tank and outlet

ment and

titanium

tanks.

of

Tank

1696.0

helium

dJJaen_ion

cubic

by the "A" package

inches.

norm_11y

is used to expel

Temperature

line to provide

tar_.

sensors

readings

the

are affixed

for the cabin instru-

telemetry.

"A" Package The "a" package valve,

8-97) consists

two high pressure

pressure

transducer

the propellant normally

activate valves

the system

_nd test

in the cabin isolation

are provided,

"F" Package

(Spacecraft

The "F" package

(Figure

pressure

to the open position

one on each side of the isolation purging

contamination

and venting

downstream

during testing

signal to

System.

Two dual seal, high pressure

isolation

The source

an electric

is used to isolate

is actuated

valve is used to test

system

valves and filters.

and transmits

valve

The valve

for operation.

transducer,

and to the Instrumentation

valve is used for servicing,

prevent

of a source pressure

tank pressure

of the system.

the downstream

filters

monitors

indicator

and ports

upstream

gas charging

closed pyrotechnic

the remainder

while

(Figure

The from to

gas charging valve.

the pressurant

components.

The tank,

The valve

and servicing.

8 thru 12 Only) 8-97) consists

of a source pressure

8-352 CONFIDENTIAL

transducer,

isolation

__

CONFIDENTIAL

I_

PROJECT GEMI I

MANUAL

CHARGE

VALVE

MANUAL

_

CARTRIDGE

,N_._I

TEST

VALVE

_

l

OC]-_LET PRESSURE TRANSDUCER

NOTE "F" PACKAGE ON $/C 8 & UP ONLY

Figure

8-97

OAMS

and

RCS

"A"

Package

8-353 CONFIDENTIAL

and

OAMS

"F"

Package

CH,P_R

CONFIDENTIAL

PROJECT

GEMINI

valve, two high pressure gas charging and test valves and filters.

The source

pressure transducer monitors the regulated pressure and transmits an electrical signal to the cabin indicator and Instrumentation System,indicating the amount of regulated pressure for the OAMS system.

The normally closed pyrotechnic valve

is used to isolate the pressurant from the rese_ve fuel tank.

The valve is

actuated to the open position to activate the reserve fuel system for operation. Two dual seal, high pressure gas charging valves and ports are provided, one on each side of the isolation valve.

The valve filters prevent system contamination

during testing and servicing.

"E" Package The "E" package (Figure 8-98) consists of a filter, one normally open pyrotechnic actuated valve, one normally closed pyrotechnic actuated valve, a normally closed two way solenoid valve, a pressure sensing switch, and a manual by-pass valve. The input filter prevents an_ contaminants from the "A" package from entering the "E" package.

The two pyrotechnic actuated valves are activated (open to closed

and closed to open) as required to maintain regulated system pressure, in the event of system regulator malfunction.

The two way (open-close) solenoid valve

is normally closed and functions upon crew co_and

to maintain regulated system

pressure in the event of a system regulator malfunction. senses regulated pressure from the system regulator.

The pressure switch

Upon sensing over pressure,

the pressure switch intervenes and causes the normally open valve to actuate to the closed position, closing the inlet to the pressure regulator.

The solenoid

valve, when opened, allows pressurant flow through the package after the normally opened open)

valve test

is valve

actuated is

used

to

the

to

divert

closed

position.

pressure

to the

8-3 CONP'IDlSNTIAL

The manual solenoid

by-pass v_ve,

(normal_ during

system

_

CONFIDENTIAL

__

_

PROJECT GEMINI SEDR 300

_ ._..

__

INLET

CARI_RIDGE VALVE

NORMALLY-OPEN MANUAL

VALVE

NORMALLY-CLOSED CARTRIDGE VALVE

1

L_ INLEI_FROM

REGULATOR

J

REGULATOR OUTLET-TO

J J

OUTLET

Figure

8-98

OAMS

"E"

8-355 CONFIDENTIAL

Package

I_!iI

PRESSURE

OONFIOEENTIAL

test.

In the

normal mode of operation,

nic valve

gas flows

to the system regulator.

through

the

noz_al_

open pyrotech-

In the event system regulator over pressure

malfunction_ the pressure switch Lntervenes and causes the nol_ally opened pyrotechnic

valve

to

actuate

to

normally

closed

solenoid

valve.

(pulsed)

by the

crew to

maintain

regulator

(under

pressure)

system velve

can be actuated

ouitry_ vents is

the by-pass

provided

Pressure

nor_lly of the

to the

and pressure

is

closed

position,

The solenoid regulated

open

open valve solenoid

the

diverting

valve system

is manually pressure.

malfunction

3 the

position.

Simultaneously

is

activated

valve.

In this

regulated

by the

to

pressure

the

mode,

normally

closed

to

the

controlled

In the closed

event

of

pyroteohn_c

insured

by the

cir-

position.

This

pre-

a regulator

by-pass

circuit

crew.

Regulator

The pressure re_Alator (Figure 8-99) is a conventional, mechsnlcal-pneumatic type.

The regulator functions to reduce the source pressure to regulated system

pressure.

An inlet filter is provided to reduce any contaminants in the gas to

an acceptable level.

An outlet llne is provided from the regulated pressure

chamber to the pressure switch ("E" package) and activates the switch in the event of an over pressure malfunction.

"B" Pack e The "B" package (Figure 8-100) consists of filters, regulated pressure transducer, three check valves, two burst diaphra-m,, two relief valves, regulator out test port, fuel tank vent valve, Inter-check valve test port, oxidizer tank vent valve, and two relief valve test ports.

The inlet filter reduces any eonta_._nantsin

8-3 CONFIDIENTIAI.

CONFIDENTIAL

a,'_

PROJECT

GEMINI

__

AREA MULT I PLYI NG

OUTLET

(ROTAr ED FOR

-METERING VALVE

VALVE

Figure

8-99

OAMS

and

RCS

8-357 CONFIDENTIAL

Pressure

Regulator

CONFIDENTIAL i_.

SEDR300

L_y-

--

RELIEFVALVE

INLET

RELIEF VALVE GROUND

TEST

OUTLET TO FUEL TANK

OUTLET TO OXIDIZER TANK

Figure

8-100OAMS

and

RCS

8-358 CONFIDENTIAL

"B"

Package

CONFIDENTIAL

PROJECT

the gas to an acceptable taminants

from entering

the regulated

craft

5 and 6.

gas system.

devices

two relief

valves

pressure.

In the event of burst

Manual

Fuel

pressure

and ports

signa_

diaphragm

thereby,

reseats

prevents

are safety

the design

are provided

into the back-

(over pressure)

failure

pressure,

bladders.

valve

to the closed position

to vent, purge

on space-

type with preset

the relief

venting

indicator

side to prevent

on the propellant

rupture,

monitors

pressure

of fuel vapors

diaphragms

imposed

tr8nsducer

of regulated

reaches

any con-

to the cabin

mecb_nlcal-pneumatic

The valve

level is reached,

valves

from being

prevent

pressure

backflow

pressure

are conventional,

overboard.

filters

on the oxidizer

The burst

regulated

excessive

pressure

the entire

The

opening

opens

venting

when a safe

gas source.

and test the regulated

system.

Tank

The fuel storage contain

bladder surant

surant

(Figure

bladder

8-101)

is imposed

layered

Teflon,

on the exterior

to the thrust

chamber

and vent the fuel t-nk. line, fuel tank exterior

cabin indicator

is welded,

and purge

and has a fluid volume

is a triple

"D" package purge

tank

an internal

in diameter,

J_

when

prevents

are provided

preventing

pressure

the amount

check valve

into the system.

that rupture

excess

an electric

System, indicating

Two check valves

inlet

The regulated

and transmits

A single

flow of oxidizer

Test valve

the system.

pressure

and Instrumentation

level.

GEMINI

port.

The tank

spherical

_imension

capacity

of 5355.0! cubic

positive

expulsion itype.

of the bladder solenoid

Temperature and output

and Instrumentation

titanium

to expel

valves. sensors

Purge

System.

8-359 CONFIDENTIAL

is 21.13

inches.

inches

The tank

The helium

pres-

the fuel through ports

arei affixed

line to provide

tank which

the

are provided to the iaput

readings

for the

to pres-

CONFIDENTIAL

__

PROJECT

GEMINI

PRESSUREANT

¢

¢ PROPELLANT

Figure

8-101 OAMS

Propellant

8-360 CONFIDENTIAL

Tank

CONFIDENTIAL

Ii_

PROJECT

GEMINI

5.10

_=i'I

Do _%. .....

,,_

ROPELLANT

PRESSUREANT

Figure

8-102

RCS

Propellant

8-361 CONFIDENTIAL

Tanks

|

CONFIDENTIAL

PROJECT _.

GEMINI

_SEDR

Reserve

Fuel

_,_

The reserve contains

fuel an

diameter,

tank

inter-=1

30.7

cubic

inches.

expel

fuel

Oxidizer

"C" and

the

on_y)

8-102)

is

a welded

and purge end

port.

has

a

is

"D" package

8-101)

and purge port.

capacity

to

ti_n_m

The i_uid

the

cylindrica_

tank

is

5.10

tnn_

inches

capacity

of

_.0

on the

exterior

of

the

thrust

chamber

solenoid

which

outside

volume

imposed

is a welded

The tank

expulsion

type.

The helium

to expel the oxidizer

are affixed

line to provide

inches

The _nk

pressurant

through

Purge ports are provided

titanium

is 21.12

of 5355.0 cubin inches.

bladder

to

valves.

bladder

and vent the oxidizer

for the cabin

Teflon, of the

cb_ber

tanks.

oxidizer

indicator

layered

on the exterior

to the thrust

line,

contain

and has a fluid

is double

is imposed

to the i_put pressurant

readings

te_k which

in diameter,

the "C" package

to purge

spherical

solenoid

Tempera-

tank exterior

and Instrumentation

and

System.

"D" Packs_es and "D" (fuel) packages

tion and are located consists

test valve.

to isolate

downstream

of a filter,

The filter

from entering

waiting

12

pressurant

(Figure

The "C" (oxidizer)

package

8 thru

length

helium

t_nk

t_re sensors output

in

___

Tank

positive

valves.

inches

through

a bladder

bladder

(Figure bladder

The

The oxidizer

volume

(Spacecraft

3O0

propellants

period.

of the tanks

isolation

is located

the downstream

8-103) are identical

of their

valve,

The normally

from the remainder isolation

respective

propell_nt

at the outlet port

system.

The pyrotechnic

(Figure

cb_ging

8- 362 CONFIDENTIAL

valve

is actuated

Each and

contaminants

isolation

of the system during valve

system.

to prevent

closed

in func-

valve

is used

the pre-launch

to the open position

CONFIDENTIAL SEDR 300

.,._

___

s

__¢_,_-'

PROJECT

GEMINI

i!

_ .

CARTRIDGE VALVE

v_AL CHAROE

"......".+

_

{i_

-

MANUAL

:_

OUTLET

8-103

OAMS

and

RCS 8-363

CONFIDENTIAL

"C" and

!i::::i_ i

t__J....

INLET

Figure

VALWE

"ii:::!J: i:_:_:!: _'__

__._

CHARGE

"D"

Package

CONFIDENTIAL

PROJECT

for

system operation.

isolation

_/_e

and is

The propellant used for

GEMINI

chA.rglng

sez_rlci_

valve

and venting

is

located

the

upstream

system.

of the

The test

valve is located downstream of the isolation valve and is used to test the downstream

system.

Propellant Supply Shutoff Valves Propellant supply shutoff valves (Figure 8-i04) are provided for both the oxidizer and fuel system and are located downstream of the "C" and "D" packages. The motor driven shutoff valves are electrically operated and ._n-Ally controlled. The propellant valves serve as safeguards in the event of TCA leakage.

The

valves are normally in the open position, and are closed at the option of the crew to prevent loss of propellants.

The valve is thereafter reopened only when

it is necessary to actuate the TCA's for the purpose of the spacecraft control.

Thrust Chamber Assembl_ (TCA) Group Each TCA (Figure 8-i0_, 8-106 and 8-IO7) consists of two prope11_nt

solenoid valves,

an electric heater, injection system, calibrated orifices, combustion chamber and an expansion nozzle.

The propellant solenoid valves are quick acting,

normally closed valves, which open simultaneously upon application of an electric signal.

This action permits fuel and oxidizer flow to the injector system.

The

injectors utilize precise Jets to impinge fuel and oxidizer streams on one another for controlled ._img

and combustion.

used to control propellant flow. c_.ber.

The calibrated orifices are fixed devices

Hypergolic ignition occurs in the combustion

The combustion chamber and expansion nozzle are lined with ablative

materials and insulation to absorb and dissipate heat, and control wall temperature.

8-36 CONFIDENTIAL

CONFIDENTIAL

PROJECT

GEM

,I _-\\_'_'_'I

iNLET FILI_R

_tPPLE

_

I_\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\_\\\\\\\\\\\\

!

f-.

Figure

8-104

OAMS

and

RCS

Propellant

8-365 CONFIDENTIAL

Shutoff

Valve

CONFIDENTIAL

SEO,

PROJECT

GEMINI

NOTE LONG LIFETCA'SAREUSEDON MISSIONS REQUIRING EXTENSIVEMANEUVERINGOR EVA (EXTRAVEHICULARACTIVITY).

,N_E_OR

,CON,_L,_

,

i_

//

,,

(

I_ _

LONG LiFE

6° ORIENTED._r ABLATIVE

L--'CERAMIC LINER (I PIECE,)

MOUNTING

SHORT LIFE

PARALLEL WRAP (STRUCTURAL)

ABLATIVE

Figure

8-105OAMS

25 Lb. TCA

8-366 CONFIDENTIAL

_

CONFIDENTIAL

(STRUCTURAL) INJECTOR ABLATIVE WRAP f_

i

NOTE " INSERT CAN

LINER 6° ORIENTED" ABLATIVE

(1 PIECE)

LONG LIFE

CAN 90° OpJENTED -_ ABLATIVE

(SEGMENTED)

f--

SHORT LIFE Figure

8-106 OAMS 8-367 CONFIDENTIAL

85 Lb. TCA

LONG

LIFE TCA'S ARE USED ON MISSIONS

Ec_IENSIVE A TIVITY) , MANEUVERING

REQUIRING

OR EVA (EXTRA VEHICULAR

CONFIDENTIAL

PROJECT

GEMINI

NOTE LONG LIFE TCA'S ARE USED ON MISSIONS REQUIRING EXTENSIVEMANEUVERINGOR EVA (EXTRAVEHICULARACTIVITY).

(STRUCTURAL) MOUNTING CAN

F

GLASSWRAP ASBESTOS WRAP

PARALLEL WRAP ABLATIVE

PROPELLANT VALVES

.::=:__

LONG LIFE

-

I1 -

.,

CERAMICLINER-(I PIECE)

ABLATIVE

MOUNTING

(STRUCTURAL)

PROPELLANT

ABLATIVE

WRAP

!

_._

SHORT LIFE

INJECTOR' 90° ORIENTED ABLATIVE CERAMICLINER' (SEGMENTED)

'PARALLEL WRAP ABLATIVE

Figure 8-i07 OAMS

I00 Lb. TCA

8-368 CONFIDENTIAL

CONFIDENTIAL

PROJECT _.

GEMINI SEDR300

_'s with

_-e installed the

suitable

outer for

are installed

within

mo_line

the adapter

and located

the attitude on the _A

_d

with

at various

._neuveri_

oxidizer

the nozzle points

_Llves

control

exits about

required.

to prevent

tez_t-_ti_

flush

the adapter

section

Electric

the oxidizer

heaters

from freezing.

Tubing Cutter/Sealer The tubing cutter/sealer is a pyrotechnic actuated device and serves to positively seal and cut the propel!_t

feed lines.

Two such devices are provided

for each feed llne and are located downstream of the prope_A-t

supply o_off

valve, one each in the retrograde and equipment section of the adapter. retrofire, the equipment section is Jettisoned.

Prior to

The devices are actuated to

permit separation of the feed lines crossing the parting line, and to contain the propellants upon separation.

RE-EmTRY CORTROL ,Sysn_m_ , ,, ,

SYSTEM _SCRIPTION The Re-entry Control System (RCS) (Figure 8-108) is a fixed thrust, cold gas pressurized, storable liquid, hypergolic hi-propellant, self contained propulsion system used to provide attitude control of the spacecraft during re-entry.

The RCS consists of two and independent systems.

identical but entirely separate The systems i._y be operated

individual/_ or simultaneously.

One system will be des-

cribed, all data is applicable to either system.

The RCS is capable of operating outside of the earth's atmosphere.

8-369 CONFIDENTIAL

CONFIDENTIAL

I-

. -.

___,r-:,,_:_ ,

PROJECT

SEDR 300

_

GEMINI

...

RCS THRUST CHAMBER ATTITUDE CONTROL

@ ,_

@ ©© _ ©Q

_,Tc. 0o',,. Y..'.,,O.T

FUE_SOL,.O,D GQ RO,L,,G.T T.,0STC._,_,E,_,RA.GE_E.T QG RO,_LE,T

DETAIL A

"3" SYSTEM FUEL SrCUTOFF/ON VALVE "B" SYSTEM FUEL 'A"

OXIDIZER

TANK

SYSTEM

FUEL SrlUTOFF/¸ON %" SYSTEM

_COMPOix,

ENT PACKAGE "D"

OX_DIZ ER SHUTOFF/ 'A" S'fSTEM

-- "A"SYSEEM

FUEL

_

COMPONENI PACKAGE "C"_

OXIDIZER

SHUTOFF/ON

'dALVE

_. PRESSURANT TANK

"A"SYSTEM OXID

_

(REF/

#. .k VENT _TYP2

_

PRESSURANT

tJ I

4PONENT PACKAGE 'B'

PACKAGE

"A"

_IC©MPONEht

sI

Z 173 97_%_ •

/ it

COMPONEN[ PACKAGE "C"

COMPONENT PACKAGE

"9

js

-Tt_RLST ChAt45ER IEYP I_ PLACLSJ

COMPONENT

PACKAGE

"A'

_ COMPONENT

PACKAGE

"C

BY LSEE

Figure

8-108

Re- entry

DETAIL "A" (TYP 16 PLACERI

Control

"A" and "B" Systems

8-370 CONFIDENTIAL

Z

_1 97

ASSE_2LY

CONFIDENTIAL

/

.

SEDR300

Attitude control (roll, pitch and yaw) is obtained by firing the TCA's in groups.

The TCA's are mounted at various points about the RCS section of the

spacecraft consistent with the modes of rotational control required.

The entire

RCS, (ta_ks and control packages), with the exception of instrumentation, is located in the RCS section of the spacecraft.

Each package consists of several

functioning components and filters.

The delivery of pressura_ts and prope_1--ts i is accomplished by a uniquely brazed tubing manifold _ystem. The HCS is divided into three groups; pressurant group, the oxidizer/fuel (propellant) group and the Thrust Chamber Assembly (TCA) group.

Pressurant

Group

The pressurant group (Figure 8-109) consists of a pressurant tank, "A" package, pressure regulator _nd "B" package.

Valves and test _orts are provided at

accessible points to permit servicing, venting, purging and testing. provided throughout the system to prevent system cont_nation.

Filters are

The pressurant

is stored and isolated from the remainder of the system during pre-launch periods by a normally closed pyrotechnic actuated valve, located in the "A" package.

Fuel/Oxidizer Group The fuel/oxidizer (propellazr_)group (Figure 8-109) consists of expulsion bladder storage tanks, "C" (oxidizer) and "D" (fuel) packages i

Valves, ports and test

ports are provided at accessible areas to permlt servicing, venting, purgi_ testing.

Filters

The propellants by normally are

provided

are are

closed on the

provided

isolated

throughout in the

pyrotechnic "C" package

the

storage

actuated

system

tanks

valves

to maintain

the

8-371 CONFIDENTIAL

to prevent !

from the

in the"C" oxidizer

and

conta_nation.

reminder

of the

and "D" packages. at an operating

system Heaters

temperature

CONFIDENTIAL SEDR300

.--_,.

__;.,.

PROJECT

GEMINI

--.

(i OX'D'ZE " I....... U

I..........=_ E_O_LPRESS j MANUAL VALVE

HIGH PRESSURE

TEST

VALVE

NRFUELTANK ","PACKAOE

VENT VALVE j

OOR_ DIAPHRAGM

FILTER

Ig

''1_ F,LTER I HEATER

........... _ .............. _...__.o? ...........

--

)J

REL,EE

I PACKAGE

"O"RACKAGEL _ I|

VALVE

OVERBOARD ZJ_VE NT

NORMALLY CLOSED PYROTECHNIC VALVE

Z[_ RELIEF VALVE IEST PORT PRESSURE REGULATOR 'J

I TEST

' __:_' INTERCHECK VALVE TES

CLOSED

PRESSURE

MANUAL

FILTER

r_ II BURST

j _. N2OXIDIZER TANK VENT

NORMALLY

................... i"_"""f"" ........ T"-,T_NK I

VALVES ,

HIGH

_

8TEST PORT RELIEF VALVE

FILTER

DIAPHRAGM

_1_ SOURCESENSOR _ALTES_ T T_."_EB --

J--

--TEMP

RELIEF

VALVE

MAIN NORMALLY CLOSED PYROTECHNIC VALVE

VALVE

r

_] OXIDIZER

PURGE

VALVE

Figure

8-109

,_c,, PACKAGE

J

,_,............................................. ff.--..-.::.,__ :i:.:.:.,:.ii__i:i)2_.!.;....... i.............

j......._.....l

TANK

_

RCS

(Single

System)

8-372 CONFIDENTIAL

(Sheet

1 of 2)

CONFIDENTIAL SEDR300

j-_

.,.

PROJECT

GEMINI

EDRSTAL PANEL

25R

,_

--FUEL

SUPPLY

OFF/ON

OXIDIZER OFF/ON

25 #

VALVE

SUPPLY VALVE

2.5R

25t, 'ALVE (8 TYP.) )XIDIZER

J

VALVE HEATER

(8 TYP)

IL_ RIGHT SWITCH AND

CLRCUIT B,EA_,E_ PANEL

FigureS-109

RCS

(Single

System)

8-373 CONFIDENTIAL

(Sheet

2 of 2)

CONIFIDtNTIAL

PRMINI _.

SEDR300

The propel

1-_ts

used

are:

Oxidizer

- Nitrogen

Tetroxide

Specification Fuel

_

(N20_)

conforming

to

- P - 26539A

- Monomethyl _7drazine (_H3CH3)

conforming

to specification MIL - P - 27_04

,,,,T_st Chamber Assemhl_r(TCA) Gmm*_ The TCA group (Figure 8-108) consists of eight twenty-five pound TCA's used for attitude (roll, pitch and yaw) control of the re-entry module. equipped with thrust c_.ber

Each TCA is

and electric controlled solenoid valves.

are provided on the oxidizer solenoid valves to ._ntaln

Heaters

the oxidizer at an

operating temperature.

SYS_

OPERATION

Press urant Group (Figure 8-105) High pressure nitrogen (N2) (pressurant), is stored at 3000 psi in the pressurant tank. gas charging port.

The tank is serviced through the "A" package high pressure

Pressure _

the pressurant tank is isolated from the re-

,_Inder of the system, until ready for operation, by a normal/_ closed pyrotechnic actuated valve located in the "A" package.

Stored nitrogen pressure is monitored

and transmitted to the cabin indicator --4 Instrumentation System by the source pressure transducer located in the "A" package.

Upon co,_-nd, the "A" package

p_Totechnic actuated valve is opened (simultaneously with propellant "C" and "D" package pyrotechnic actuated valves) and nitrogen flows to the pressure regulator and "B" package.

The "B" package provides a division of flow to the

8-37 CONIFIDRNTIAI..

CONFIDENTIAL

PROJECT __

GEMI

SEDR300

propellaut

tanks.

transducer

("B package)

indicating

pressure

flow

The regulated

and provides

downstream

of propellant

pressure

vapors

sensed

a signal

of the

into

is

the

to

by the

the

regulator.

regulated

Instrumentation

The check

pressurant

pressure

system.

valves

System, prevent

The "B" packa6e

back-

also

pro-

i vides

a safety

bladders. over

feature

Should

pressure

thro-_h

the

Fuel

relief

prevent

system first

over

be over

rupture

pressure

of thej i fuel

and oxidizer

tank

pressurized

the

burst

downs_reem of the regulator the i diaphra_s_ then be vented overboard

valves.

Group

and oxidizer

se_v£ced

the

would

Fuel/Oxidizer

to

(propellants)

through

the

high

are

pressure

stored charging

in their ports

respective tanks, and are i in the "c" and "D" packages.

The propellants are isolated from the remainder of theisystem, until ready for I operation, by the normslly closed pyrotechnic valves i_ the "C" and "D" packages. Upon command the "A" (pressurant), "C" (oxidizer) and i"D" (fUel) package pyrotechnic actuated valves are opened and propellants areidistributed through their

! separate tubing -_nifold system to the thrust chamber _nlet solenoid valves.

Two motor

driven

shutoff

upstream

of the

TCA's.

solenoid

valves,

the

loss

the

In the motor

of propell--ts.

quired,

to

output

s,ltch

deliver lines

valves

are event

operated

The valves propellants of the

"C" and

located of fuel valves

can again to

in the

the

or oxidizer

!

feed

leakage

lines, through

the

TCA

can be closedI by the crew to prevent ! be actuate_ open by the crew, when re-

TCA solenoids.

"D" packages

8-io9).

Thrust Chamber Assemb_

propellant

,,(TCA)Grou_

8-3T5 CONFIOINllAL

and are

Heaters

!

activated

are

connected

by the

to

RCS HTR

CONFIDENTIAL SEDR 300

PROJECT GEMINI Upon crm_nd through

from the

the

Attitude

Control

open siemltaneously, valves

mounted

through oxidizer

into

freeze-up

and are

Electronics

closed,

the

are

quick

acting

_o the

they

connected

to

by the

are transmitted

(ACre)

to

fuel

signals,

combustion

where

activated

signals

controls,

In response

on one another_ Heaters

_CA's

and oxidizer

propellants

chamber.

ignite

selected

solenoid

are

dirocted

The controlled

hypergolically

each

TCA oxidizer

RCS H_

switch

to

fuel

_n_

burn and

solenoid

(Fi@ure

to

valve

to

pre-

8-10_).

UNITS

Pressurant

Stora6e

The nitrogen tank is

T=-_

(N2) pressurant

7.2_ inches

inches.

Nitrogen

pyrotecBn4c oxidizer surant

normally

Jets

thrust.

SYS_

Maneuvers

TCA.

injector

impinge

create vent

the

on each

small

or m,,_

autcmstic

from outlet

outside

gas is

valve.

This

their line

is

diameter

stored

in a welded,

and held

under pressure,

tanks.

provide

tit_nttt_

and has an inter_l

at SO00 _si

nitrogen,

respective to

stored

is

Temperature the

volume of therein used

sensors

readings

for

cabin

consists

of a source

_-k.

spherical

185.0

by the to are

instrument

The

cubic

"A" package

expel

the

affixed

fuel to

and

the

pres-

and telemetry.

"A" pachage,, The "A" package valve,

filters

transducer cabin isolation

(Figure

and two high

monitors

indicator valve

8-9?)

the

stored

indicating is

used

pressure

the to

gas

charging

pressure valves.

transducer, The source

pressure

and transmits

an electric

pressure

of the

stored

gas.

pressure

from

isolate

the

system.

the

isolation pressure

signal

The normally remainder

to

the

closed

of the _

8-$76 CON

FIDIWNTIA

/

GONFIDENTIAL

__.

SEDR300

i

The valve is pyrotechnically actuated to the open position to activate the i

system for operation.

Two dual seal, high pressure _s i

are provided, one on each side of the isolation val_.

chargim_ valves and ports The upstream valve is

I

used for servicing, venting and purging the pressuraut tank, while the downstream valve is used to test downstream components.

Filter_ are provided to prevent con-

taminants from entering the system.

Pressure,, Re_l_, tor The pressure regulator (Figure 8.99) is a conventional , mechanical-pneumatic type. i The regulator functions to reduce the source pressure to re_ated system pressure. An inlet filter is provided to reduce any contaminants in the gas to an acceptable _

level.

"B" Package The "B" package (Figure 8-100) consists of filters, regulated pressure transducer, three check valves, two burst diaphragms, two relief ivalves, regulator output i test port, fuel tank vent valve, oxidizer tank vent valve, inter-check valve test port and two relief valve test ports.

The inlet fil_r

reduces any contaminants

I

in the gas to an acceptable level. entering the system.

Valve inlet filt(_rsprevent contaminants from

The pressure transducer monito .sthe regulated pressure and l i

transmits an electrical signal to the spacecraft Ins_;rumentationSystem. i check valve prevents hackflow of fuel vapors into th_ gas system.

A single

Two check valves

are provided on the oxidizer side to prevent backflo_ of oxidizer vapor into the gas system.

The Burst diap_s

are safety devices that rupture when the reg-

ulated pressure reaches the design failure pressure, sure from being

impose_

on the

propel!e_nt

bladders.

8-3Ti" CONIIIIDIN'FIAL.

)reventing excessive pres-

CONFIDENTIAL

PROJECT

GEMINI

•he tWO relief valves are convention_! mechanical-pne--_tic type with preset opening pressure.

In the event of burst diaphragm rupture, the relief valve

opens, venting excess pressure overboard.

The valve reseats to the closed posi-

tion when a safe level is reached, preventing the entire gas source from bei_ vented overboard.

M_n,_LIvalves and ports are provided to vent, purge and test

the regulated system.

Fuel Tank The fuel tank (Figure 8-102) is a welded, titanium cylindrical tank which contains an internal bl_dder and purge port.

The tank is 5.10 inches outside diameter,

30.7 inches in length and has a fluid volume capacity of _6.0

on the exterior of the bladder to expel fuel

The nitrogen pressv_c_utis i_osed

through the "D" package to the TCA solenoid valves. to purge

and vent

the

fuel

tank

cubic inches.

bladder.

T_erature

The purge port is provided sensors

are

affixed

to the

nitrogen input line and fUel output line to transmit signals to Instrumentation System.

Oxidizer

Tank

The oxidizer tank (Figure 8-102) is a welded, titanium cylindrical ta-_ which contains a bladder and purge port.

The ta_k is 5.10 inches outside diameter,

25.2 inches in length and has a fluid volume capacity of 439.0 cubic inches. The bladder is a double layered Teflon, positive expulsion type. pressurant is i_sed

The nitrogen

on the exterior of the bladder to expel the oxidizer

through the "C" package to the TCA solenoid valve.

The purge port is provided

for purging and venting the oxidizer tank bladder.

Te_erature

sensors are

affixed to the nitrogen input line and oxidizer output line to transmit signals to Instrumentation System.

8-3 CONFIDENTIAL

GONFIDEINITIAL. SEDR 300

_ "C" and

"D" Packages

The

and

,,,

"C"

downstream

"D" packages of

filters,

the

(Figure

tanks

an isolation

of

at outlet

valve

and port

filters

mall_

closed

of the system actuated valve

venting

the pro-launch

for system

valve

P_opellant

Sup pl_ Shuto_

Valves

pr_llaut

supply

valves

system.

controlled. option when

shutoff

and are located

The motor

driven

The valves

shutoff

of the crew to prevent

the TCA's are needed

TCA (Figure

calibrated

_-ii0)

orifices,

function

valve

of The

level.

the system.

The isolation

The

The nor-

from the remainder valve

is pyro_echnlc

The prope_Rnt

and is used

downstream

located

consists

tO an acceptable

c_e_tion.

are

and test valve.

propellants

v_ive

and

package

from entering

is located

char_Ing

for servicing

and

of the isolation

valve

system.

(Figure

8-104)

downstream valves

are normally

are provided

for both

the oxidizer

of the "C" and "D" packages

are electrically

operated,

in the open position,

loss of propellants.

for spacecraft

semb Each

period.

of the isolation

The test

in Each

contaminants

contaminants

and is used to test the downstream

and fuel system,

cb_rgiDg

valve is used to isolate

upstream

the system.

identical system.

propellant

portj reduces

to the open position

is located

are

respective

prevent

isolation during

their

valve_

filter, located

8-103)

-]

in the

and w_nual_y

and are closed

The valves

at the

are reopened

onl_

control.

Qrou

consists

combustion

of two propellant chsmber

valves,

and expansion

in_ection

nozzle.

system,

The fuel and

i

oxidizer _

solenoid

simultaneously

valves

are quick acting,

upon application

normall_

of an electric

8-379 CONFIOla'NTIAL

closed

signal.

valves,

The action

which

open

permits

fUel --d

CONFIDENTIAL SEDR 300

4IF (STRUCTURAL) MOUNTING

INJECTOR PARALLEL (SEGMENTED) 90° ORIENTED' ABLATIVE

Figure

8-110

-_'_

RCS 8-380

CONFIDENTIAL

25 Lb.

TCA

CONFIDENTIAL m._mmwmmmmm_

PROJECT ______

oxidizer fuel

_.ov into

and oxidizer

The oaltbz_ted 1_ergolio

GEMINI

SEDR 300

the

injector

streams orifices

ignition

system.

on one e_other

are fixed

occurs

in the

devices

The lnJeetorm for

controlled

used to

combnstton

use precise Lt_

control

chember,

Jets

to impinge

and o_ustion.

propellant

The c_stion

flow. c_m_er

and expansion nozzle is lined with ablative materials and insulation to absorb and dissipate heat and control external wall temperature.

TCA's are installed

within the RCS section mold line, with the nozzles terminating flush with the outer mold line.

TCA's are located at fixed points in the RCS section in a

location suitable for attitude control.

Electric heaters , located on the oxidi-

zer valve, are used to prevent the oxidizer frcm freezing.

8-381/382 CONFIDENTIAL

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