Nasa Hubble Space Telescope Reference Guide

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(NASA-CR-193386) TELESCOPE. MEDIA (Lockheed 57 p

Missiles

HUMBLE REFERENCE and

SPACE GUIDE

Space

N93-7269q

Co.) Ue_las

Z9/89

Hubble

Space

0[79_93

Telescope

Reference

Published

National

Aeronautics

For:

& Space

Published

-__

Media Guide

Administration

By:

Missi#es& SpaceCompany,#no. Sunnyvale,

California

CONTENTS

Section 1

Page

1.1

1.2

V

1-1

INTRODUCTION Hubble

Space

1.1.1

Support

Systems

1.1.2

Optical

Telescope

1.1.3

The

1.1.4

Solar

1.1.5

Computers

The

Configuration

1-2

Module

1-2

Telescope

Scientific

Hubble

1-4

Assembly

1-4

Instruments

1-7

Arrays

1-7

Space

Telescope

1-7

Program

1-8

1.2.1

Development

1.2.2

Launch-and-Deployment

1.2.3

Verification

Phase

1-9

1.2.4

Operational

Phase

1-10

1.2.5

Maintenance

THE

HUBBLE

2.1

The 2.1.1

2.1.2

2.1.3

2.1.4

SPACE

Support

Phase

1-11

Phase TELESCOPE

Systems

Structural

1-9

Phase

2-1

SYSTEMS

2-2

Module

and

Mechanisms

2-3

Subsystems

2-3

2.1.1.1

Aperture

2.1.1.2

Light

2.1.1.3

Forward

2.1.1.4

Equipment

Section

2-5

2.1.1.5

Aft

and

2-7

2.1.1.6

Mechanisms

Door

2-4

Shield

Shroud

Instrumentation

2-4

Shell

and

Bulkhead

2-7 Communications

2.1.2.1

High-Gain

Antennas

2.1.2.2

Low-Gain

Antennas

Data

Management

2-8

(HGA)

2-8

(LGA)

2-9

Subsystem

2.1.3.1

DF-224

2.1.3.2

Data

Management

2.1.3.3

Data

Interface

2.1.3.4

Engineering/Science

2.1.3.5

Oscillator

Pointing

2-8

Subsystem

Control

2-9

Computer

2-10

Unit

2-10

Unit Tape

2-11

Recorders

2-11 2-11

Subsystem

2.1.4.1

Sensors

2-11

2.1.4.2

PCS

2-13

Computer

iii

PII_6_D_NG

PAGE

BLANK

NOT

FILMED

Section

Page

2.1.5

2.1.4.3

Actuators

2-13

2.1.4.4

PCS

2-14

Electrical

Power Solar

2.1.5.2

Batteries

Thermal

2.1.7

Sating

2.2.1

2.3

2.4

2.5

2.6

Primary

Distribution

Controllers

2-14

Units

2-15

2.2.1.1

Primary

2.2.1.2

Main

2.2.1.3

Reaction

2.2.1.4

Baffles

Plane

2.2.4

OTA

Equipment

2-16

RMGA

2-18

Assembly

2-19

Assembly

2-20

Mirror

2-20

Ring

2-21 Plate

2-22 2-23

Mirror

Guidance

System

and

Mirror

Focal

Assembly

Structure

2-23

Assembly

2-25

Section

2-26

Sensors

2.3.1

FGS

2.3.2

Wavefront

2-26

Composition

and

Function

2-27

Sensor

2-28

Arrays

2-29

2.4.1

Configuration

2.4.2

Solar

2.4.3

Operation

Scientific

2.5.2

and

Current

2-16

Telescope

2.2.3

2.5.1

Charge

Control

PSEA

Secondary

Solar

and

(Contingency)

2.2.2

Fine

2-14

Control

2.1.7.1 Optical

2-14

Arrays

Power

2.1.6

The

Subsystem

2.1.5.1

2.1.5.3

2.2

Operation

2-29

Array

Subsystems

2-29 2-30

Instrument SI C&DH

Control

and

Data

Handling

Unit

Components

2-30 2-31

2.5.1.1

NASA

Computer

2.5.1.2

STINT

Unit

2.5.1.3

Control

2.5.1.4

Power

2.5.1.5

Remote

2.5.1.6

Communications

2-31 2-31

Unit/Science Control

Data

Unit

Module

Units Buses

Operation

Formatter

2-31 2-32 2-32 2-32 2-32

2.5.2.1

System

2.5.2.2

Command

2.5.2.3

Science

Space

Support

Equipment

2.6.1

Flight

Support

Monitoring Processing Data

Processing

2-32 2-32 2-32 2-33

Structure

2-34

iv

Section

Page

THE 3.1

2.6.2

Orbital

Replaceable

Unit

2.6.3

Orbital

Replaceable

Units

2.6.4

Crew

3.1.1

3.2

Physical

3-1

Camera

3-1

Description

3-2

3.1.1.1

Optical

3.1.2.2 3.1.1.3

The Photon Detector FOC Electronics

3.1.3

Faint

3.1.4

Observations

System

Object

3-5

System

3-6 3-6

Camera

3-7

Specifications

3-7

3.1.4.1

Stellar

3.1.4.2

Measuring

3.1.4.3

Globular

3.1.4.4

Examining

Object

3-2

Modes

Evolution

3-7

Distances Clusters

3-8 and

Solar

Galaxies

System

3-9 3-10

Objects

Spectrograph

Physical

3-10

Description

3-11

3.2.1.1

Optical

System

3-11

3.2.1.2

Digicon

Detectors

3-12

3.2.1.3

Electronics,

3.2.2

Operational

3.2.3

Faint

3.2.4

Observations

The

2-35

Object

Observation

Faint

2-35

INSTRUMENTS

3.1.2

3.2.1

3.3

Faint

2-34

Aids

SCIENTIFIC The

Carrier

Power,

Object

3-13

Spectrograph

3.2.4.2

Supernovae

3.2.4.3

The

Evolution

3.2.4.4

The

Composition

High

Comparison

3.3.2

Physical

Specifications

3-13 3-13

Explosive

3.3.1

3-12

Modes

3.2.4.1

Goddard

Communications

Galaxies and

3-14 Distance

3-14

of Stars

3-15

of Interstellar

Matter

3-16

Resolution

Spectrograph

3-16

with

Object

3-16

Faint

Spectrograph

Description

3-16

3.3.2.1

Apertures

3-17

3.3.2.2

Carrousel

3-17

3.3.2.3

Cross-Dispersers

3-18

3.3.2.4

Digicon

3-19

3.3.2.5

GHRS

3.3.3

Operational

3.3.4

Goddard

3.3.5

Observations

Detectors Software

3-20

Modes High

Resolution

3-20 Spectrograph

Specifications

3-21 3-21

Section

Page

3.4

High

3.6

3.3.5.2

Content

3.3.5.3

Star

3.3.5.4

Quasars

Composition

of the

Extragalactic

Optical

3.4.1.2

General

Observations

Detector HSP

High

Photometer

3.4.4

Observations Measuring

3.4.4.2

Search

3.4.4.3

Occultation

3-25

Operation

Specifications

Stellar for

Magnitudes

Pulsars

Camera

3.5.1

Comparison

of WF/PC

3.5.2

Physical

3-28

and

3-30

FOC

3-31

Description

3.5.2.1

Optics

3.5.2.2

Charge-Coupled

3.5.2.3

Processing

Wide

3.5.5

Observations

Detectors

3-33

Modes Camera

3.5.5.2

Planets

3.5.5.3

Martian

3.5.5.4

When

(Fine

Operational

3.6.3

FGS

3.6.4

Astrometric

Specifications

3-33 3-34

Photographing

3.6.2

3-32 3-33

System

3.5.5.1

Fine

3-31

System

Field/Planetary

3.6.1

3-28

3-29

Field/Planetary

3.5.4

3-28

3-28

Observations

Wide

Operational

3-24

3-28

3.4.4.1

Dust

Hole

Systems

Storms

Galaxies

Collide

3-35

Specifications

for Astrometry

and

4.1.2

Predeployment

4.1.3

Contingencies

3-36

3-37

MISSION

DESCRIPTION

4-1 4-2

Deployment

Launch

3-36

3-37

Observations

4.1.1

3-34

3-34

Wheel

TELESCOPE

3-34

3-34

Sensors)

Sensor Modes

Filter

a Black

in Other

Guidance

Guidance

and

Subsystem

3-27

3.4.3

3.5.3

3-22

3-23

Modes

Speed

3-22 3-22

Binaries

Description

Operational

Launch

Medium

3-21

3-23

3.4.1.1

SPACE

Dispersion

Photometer

Physical

Astrometry

and

and

and

Interstellar

Formation

3.4.2

HUBBLE 4.1

Atmospheric

Speed

3.4.1

3.5

3.3.5.1

4-2

Predeployment

4-2

Checkout for

Launch

and

Predeployment

4-3

4.1.3.1

Launch

4-3

4.1.3.2

Predeployment

4-3

vi

Page

Section 4.1.4

4.2

Mission 4.2.1

4.4

4.1.4.2

Deployment

4.1.4.3

Release

4.1.4.4

Deployment

4.1.4.5

Return

4-3

in Space

into

of Appendages

4-4

Orbit

4-5

Contingencies

4-5 4-7

to Earth

4-8

Operations

4-8

Verification

4.2.1.1

Orbital

Verification

4.2.1.2

Scientific

4-8

(OV)

4-10

Verification

4-11

4.2.2.1

Space

Telescope

Science

4.2.2.2

Space

Telescope

Operations

Operational

Control

Orbital

4.2.3.2

Maneuver

4.2.3.3

Communication

Maintenance

4.3.2

Reboosting

4.4.2

HUBBLE

4-16

Characteristics

4-19

Characteristics Characteristics

the

Space

4-24

Telescope

4-24

Observation

4-25

Procedure

4.4.1.1

Acquisition

4.4.1.2

Data

Observation

and

Observation

4-27

Examples

4.4.2.1

Vela

Pulsar

4.4.2.2

Supernova

4-25 4-26

Analysis

4-27

Observation

4-28

TELESCOPE

PROGRAM

MANAGEMENT

5-1 5-1

Responsibilities 5.1.1

4-20

4-22

Scenario

Observations

SPACE

4-14

4-21

4.3.1

Mission

Center

4-16

Characteristics

4.2.3.1

4-12

Institute

Maintenance

4.4.1

5.1

Placement

Operations

4.2.3

"v

4.1.4.1

Mission

4.2.2

4.3

4-3

Deployment

NASA

5-1

Responsibilities

5-1

5.1.1.1

NASA

5.1.1.2

Marshall

Space

Flight

Center

5-1

5.1.1.3

Goddard

Space

Flight

Center

5-1

5.1.1.4

Johnson

5.1.1.5

Kennedy

5.1.1.6

Other

5.1.2

Space

5.1.3

Lockheed

Headquarters

Space Space NASA

Telescope Missiles

Science

Center Center Facilities Institute

& Space

vii

Company

5-1 5-2 5-2 5-2 5-3

Page

Section

5.2

5.1.4

Perkin-Elmer

5.1.5

Scientific

Contractor

5-4

Corporation Instrument

5-4

Contractors

5-5

Contributions

Appendix A

ASTRONOMICAL A.1

Energy

and

A.I.1

Measuring

A. 1.2

Resolving

A.2

Measuring

A.3

Universe

A-1

CONCEPTS

A-1

Wavelength

A-2

Wavelengths

A-2

Wavelengths

Stars

A-2

Expansion

A-3

B

ACRONYMS/ABBREVIATIONS

B-1

C

GLOSSARY

C-1

D

NASA

E

OF

TERMS

SPECIFICATIONS

D.1

Performance/Operating

D.2

Viewing/Scheduling

ORBITAL

REPLACEABLE

FOR

THE

HUBBLE

Requirements

SPACE

TELESCOPE

D-1 D-1

Requirements

D-2

UNITS

E-1

viii

ILLUSTRATIONS

Figure

V"

Page

1-1

Overall

1-2

The

1-3

Space

Telescope

Assembled

1-4

Space

Telescope

Deployment

1-5

HST

Locks

1-6

HST

Network

Collecting

1-7

HST

Berthed

in Shuttle

2-1

Hubble

Space

Telescope

Configuration

2-1

2-2

Hubble

Space

Telescope

Axes

2-2

2-3

Design

Features

of the

Support

2-4

The

2-5

HST

2-6

Aperture

2-7

SSM

Forward

2-8

SSM

Equipment

Section

2-9

SSM

Aft

and

2-10

The

2-11

DMS

2-12

DF-224

2-13

Data

2-14

Location

2-15

FHST

2-16

Reaction

2-17

Electrical

2-18

Nickel-Hydrogen

2-19

Placement

2-20

Sating

2-21

Light

2-22

Fields

of View,

2-23

OTA

Components

2-24

The

2-25

Primary

2-26

Primary Mirror

2-27

The

2-28

Secondary

HST

Configuration

1-2

Scientific

Instruments

1-5 1-9 1-10

Sequence

on Target

Structural

1-11 Data

1-12

Bay

Components

1-12

Systems

of the

Module

SSM

Door

and

Light

2-5

Shield

Shell

Shroud

High-Gain

2-5 Bays

and

Contents

Bulkhead

2-8

Block

2-9

Diagram

Computer

2-10

Management

Unit

of the

PCS

(Aft

Wheel

Shroud

Main

Door

2-13

Open)

2-13

Subsystem

2-15

Battery

2-15 Protection

on

SSM

Telescope

Ring Mirror

2-20

Instruments/Sensors

2-21 2-22

Mirror

Mirror

2-17 2-18

Progression

Main

Primary

2-12

Equipment

of Thermal System

2-10

Configuration

Assembly

Power

2-6 2-7

Antenna

Functional

Path,

2-4 2-4

Assembly

Detail

2-3

2-23

Assembly

Construction

2-23 2-24

and

Reaction

2-24

Plate

2-24

Assembly

ix

Page

Figure 2-29

Mirror

2-30

Focal

2-31

The

2-32a

FGS

2-32b

Optical

2-33

Solar

Array

2-34

Fitting

for

2-35

Solar

Array

2-36

SI C&DH

2-37

Command

2-38

Flow

of Science

2-39

FSS

Superstructure

2-40

Typical

2-41

Four

2-42

Portable

3-1

FOC

3-2

Layout,

3-3

F/96

Optical

3-4

F/48

Optics

3-5

Photon

3-6

The

3-7

Protostar

3-8

"Photographing"

3-9

The

3-10

Quasar

3-11

The

3-12

Optical

3-13

Two

3-14

Comparison

of Four

3-15

A Planetary

Nebula

3-16

GHRS

Structure

3-17

GHRS

Carrousel

3-18

Data

3-19

Cross-Dispersal

3-20

The

GHRS

3-21

Io's

Hot

Torus

3-22

Spectrum

with

3-23

Epsilon

Aurigae

3-24

Stellar

Collisions

Metering Plane OTA

Truss

2-25

Structure

2-25

Structure Equipment

2-26

Section

2-28

Cutaway Path,

2-28

FGS Wing

2-29

Detail

Solar

Array

Wing

Manual

Stowed

2-30

Deployment

Against

2-30

SSM

2-31

Components Flow,

ORU ORU

2-33

SI C&DH Data

in the

HST

2-34 2-35 2-35

Configuration

2-36

Payloads Foot

Major

2-36

Restraint

3-3

Subsystems

FOC

Optical Relay

Relay System

Relay

Nebula,

with

3-6 A Dark

Preplanetary

Gas

Galaxy

3-7

Cloud

3-8

Matter

A Secondary

3-9

Body

Messier

Hypothetically

FOS

3-5

Layout

System

Horsehead

Elliptical

3-4

Layout

System

Detection

3-3

Systems

3-9

87

Centered

In Messier

3-10

87

3-12

Components Path,

Examples

From

3-13

FOS of Exploding Galaxy

Galaxies

3-14

Types

3-15 3-16

and

Optical

3-17

System

3-18

Three

Grating

of Wavelength Digicon

3-19

Settings

3-19

Orders

3-20

Detector

3-23

Ring Absorption (right) Above

3-23

Lines and

Mystery

Quasar

3-24

Companion

Center

(lower

right)

3-25

Figure _V

Page

3-25

Overall

HSP

3-26

3-26

Optical

System

3-27

Filter/Aperture

3-28

Visible

3-29

Rings

3-30

The

3-31

Wide

3-32

WF/PC

3-6

Wide

Field/Planetary

Camera

3-33

Black

Hole

System

3-35

3-34

Two

Colliding

3-35

3-35

Time-Lapsed

4-1

Shuttle

4-2

RMS

4-3

Deployment

4-4

HST

4-5

Crew

4-6

Orbiter

4-7

Erecting

4-8

Crew

Member

4-9

Time

Allocation

4-10

HST

4-11

Space

4-12

A Portion

4-13

HST

4-14

"Continuous-Zone"

4-15

Observing

Venus

4-16

Using

Moon

4-17 4-18

HST Single-Axis Sun-Avoidance

4-19

TDRS-HST

4-20

MM

4-21

Maintenance

4-22

HST

In Position

on

4-23

HST

in Reboost

Position

4-24

Shuttle

4-25

HST

Instrument

4-26

Data

Transmission

4-27

HST

Passes

Configuration

3-26 Tube,

Rotating

Exploded

Configuration

3-29

Pulsar

Around

3-30

Neptune

Overall

WF/PC

3-31

Configuration

Field/Planetary

Camera

Optics

Design

in Binary Galaxies Star

Lifting

Specifications

4-2

Off

4-3

HST

of Solar

Released

and

Orbiter

the

4-4

Arrays

by Control

Rolling

Moves

Away

HST

Out

4-6

of Bay

4-7

Unbolting for

Telescope

4-9

HST

Ground

of the

the

4-7

Array

4-10

Its Orientation

Nominal

4-12

System

GSSS

Star

4-13

Catalog

4-17

Orbit Celestial

as an

4-19

Disk

4-20 4-20 4-20

Zones Decision

Mission

Out

Occulting

Maneuvers Maneuver

Trip

Reboosting

4-17

Viewing

4-18

Contact

Call-Up

4-5 4-6

Panel

SA Mast

Adjusts

3-33

3-36

Birth

Maneuvers

EVA

3-32 3-33

Imaging

Spiral

3-27

4-22

Process

4-23

Timeline

4-23

FSS

the

4-24 4-24

HST

4-26

Apertures Pathway

4-26

of Shadow

4-28

xi

Figure

Page

4-28

WF/PC

Image

5-1

Space

Telescope

5-2

MSFC

Space

Telescope

Organization

5-3

5-3

GSFC

Space

Telescope

Organization

5-3

5-4

JSC

5-5

KSC

5-6

STSci

5-7

LMSC

5-8

Hughes

A-1

Polarized

A-2

HST

A-3

Calculating

A-4

Angular

A-5

The

Space

5-2

Responsibilities

Telescope

Space

4-29

of a Nova

5-4

Organization

Telescope

Organization

5-5

Organization Space

5-5

Telescope

Space

Telescope

5-6

Organization

5-7

Organization

A-1

Light

Wavelength

A-2

Ranges

a Star's

Parallax

A-3

Measurement

Hubble

A-3

Law

A-4

xii

TABLES

Table

Page

1-1

HST,

1-2

Instrument

3-1

Faint

Object

Camera

3-2

Faint

Object

Spectrograph

3-3

GHRS

3-4

Goddard

3-5

High

3-7

Fine

5-1

Instrument

5-2

Space

E-1

HST

Scientific

Instrument

Specifications

Development

Grating

Speed

Teams

Guidance

Sensors

Ranges

and

3-13 Spectral

Spectrograph

Equipment

3-18 3-21 3-28

Specifications Teams

Resolutions

Specifications

Specifications

Development

Telescope

3-7

Specifications

Resolution

Photometer

1-8

Specifications

Spectral

High

1-3

3-36

(IDTs)

Responsibilities

ORUs

5-7 5-8 E-1

×iii

Section

I

INTRODUCTION When

Galileo

scope

peered

nearly

through

400 years

precedented

period

his small

ago, it resulted

tele-

in an un-

of astronomical

discovery.

When NASA_s Hubble Space Telescope (HST) is placed into orbit to begin its observations of the heavens, expected the

it will usher

in a period

to be as astounding

introduction

of the first

Ground-based because

through

the

has

always

observations

earth's

atmosphere,

which

ing starlight

and

must

turbulent, absorbs

particle-filled

severely

limits

thinnest

remnants

astronomers The

Space

will be able brightness

farther

same

brightness

out

in space that

The

25 times

fainter

from earth. astronomers 250 times

than

can

HST than

titude

of stars.

died

over

The

Hubble

partnership

discovered

time

is the product

NASA,

contractors,

distance

Bang" theory (The Hubble

the

and

Appendix

objects

seen

will provide universe

visible,

The

It is named astronomer

and

even

quasi-stellar clarity

Telescope

will view

possibly

fast

a major

it recedes

basis

of the beginning Law is discussed

A" "Astronomical

Space

Telescope

unusual objects

(or fineness

solar

phenomena (quasars),

of detail)

eled

as for

stars, systems,

such

as

with 10 times of earth

of the universe. in more detail in Concepts.")

It will detect

for

billion

(light-years) light

and

of

starlight

is calculated

to move

between

is estimated

the

telescopes.

that

occurred

rent

expansion

Astronomers stars, of

interstellar

the

on

close

quasars,

cond

apart

1Astronomtcal

visible

sky,

(an arcsecond

terms

only

one-tenth

is a slender

and concepts,

arcsewedge

such as "light

of

years",

1-1

other

black unusual

are explained

holes,

of the curBig Bang.

and for

answers

and the future interest will

exploding

A, "Astronomical

of

the effect

galaxies,

phenomena.

m Appendix

years

development

light

questions about the beginning the universe. Of particular

uni-

phenomena

the

of galaxies,

clouds

it takes The

15 to 20 billion

following

study

the composition

has trav-

time

and

first space

distance

in space.

to the beginning

phase can

that since

as the

points

to be

close

as the

repairable

years,

The HST will be able to separate stellar objects that seem indistinguishable because they are so in the

from

for the "Big

is designed

maintainable,

observatory.

making

galaxies,

other

after who

of the universe

old, so the HST will see events comets,

European

the internation-

nature

to how

became

long-term,

verse Space

of a

objects

study.

planets,

by recent will be stu-

periods.

Telescope

the expanding

will

and was the first to realize the true nature of galaxies. He derived Hubble's Law, which relates

of the

the farthest reaches of the universe, perhaps far away as 14 billion light years t, available

The

the A dis-

as Saturn

and

al community of astronomers. Edwin P. Hubble, an American

an object

currently

in

obtained

missions

between

Agency,

us. His work

detect

clarity

longer

Space

an

will

degree, up the sky).

as far away

fly-by

much

a galaxy's

by ground

Planets

satellite

is five

be seen

one

that makes

with the same

NASA

that

the dimmest

than

universe.

to detect

The Space Telescope with an observable larger

will give

to the

Telescope

times

telescopes.

window

a particular

of

Space Teleabove all but

of atmosphere,

an open

object

incom-

of

"pie"

tant galaxy, just a faint dot of light seen from the surface of the earth, will be resolved into a mul-

Space

astronomical

observations. Placing the Hubble scope in a 330-nmi (607-km) orbit, the

been

be made

and distorts

1/3600th

360-degree

be seen as

telescope.

astronomy

hampered

of discovery

and productive

angle,

Concepts."

to of be and

I.I

HUBBLE SPACE CONFIGURATION

The

major elements

TELESCOPE

of the HST are

Assembly (OTA), the (Sis), and a Support

ule (SSM)

structure

mechanical

support

Sis. Figure

that

houses

systems,

and Table

tions for the Hubble scientific instruments.

and

the telescope,

and

the

1-1 gives

Space

the Optical

five Scientific System Modelectronic

1-1 illustrates

configuration,

structures,

tems

Telescope Instruments

the

the

overall

HST

the specifica-

Telescope

and

its

The

overall

array

panels

storage The

Support

Systems

The Support Systems and the five Sis. earth-based

Module

Module encloses the OTA Like the dome of an

observatory,

the

SSM

contains

all

and

the Hubble

spacecraft

weighs 25,500 four antennas

power

Space

is 42.5

subsys-

Telescope.

ft (13 m) long and

ib (11,600 kg). On the outside are for communications, two solar that collect

energy

bays for electronic

SSM consists

for the HST, and

gear.

of the front-end

light

arrays

and

mounted

on

feet

provide

long,

light) in turn, receive

the

to charge

high-gain

forward

the spacecraft

ANTENNA

antennas

shell.

electrical

power the HST. information.

GAIN

The

The

arrays,

energy

(from

batteries antennas

APERTURE

which,

DOOR

SHIELD PRIMARY MIRROR

CONTROL

OPTICAL

SENSORS

(3)_

AFT

SCIENTIFIC INSTRUMENTS AXIAL

(4)

RADIAL SOLAR

Figure

1-1

Overall

1-2

HST

Configuration

ARRAY

(2}

40 sun-

send

MIRROR

GUIDANCE

are

(2)

SECONDARY

FINE

shield,

with an aperture door that opens to admit light. The shield connects to the forward shell. The solar

1.1.1

electronics,

to operate

and

Table

1-1

HST,

Scientific

Instrument

Specifications

HUBBLE SPACE TELESCOPE Weight

25,500 Ib (11,600 kg)

Length

42.5 ff (13 m)

Diameter

14 ft (4.2 m) at widest

OpticaJ System

Ritohey-Chretten design C,assegraJn telescope 189 ft (57.6 m) folded to 21 ft (6.4 m)

OplJcaJLength

94.5 in. (2.4 m) in diameter

Primary Mirror Secondary Mirror Field of View

12.2 in. (0.3 m) in diameter See inslruments/sensom 0.007 arcsec for 24 hr

Pointing Accuracy

5 mv to 29 mv

Magnitude Range Wavelength Range

1100 to 11,000 Angstroms 0.1 arcsec at 6328 Ang

Angular Resolution OrbR Orbit 13me

330 nmi (607 km), inclined 28.5 ° from equator 94 minutes per orbit

Mission FAINT-OBJECT

15 years

CAMERA

WIDE FIELD/PLANETARY

CAMERA

Weight Dimensions

700 Ib (318 kg) 1

Weight Dimensions

595 Ib (270 kg) 2

Principal Inves0gator Cor_actor

FD. Macchetto, Eur. Space Agny ESA (Domier, Matra Corp.)

Principal Invest_ator Contractor

JA. Westphal, CIT Jet Propulsion Laboratory

Op_cal Modes Field of View

f/96 f/46 11.2, 22 arcsec 2

Optical Modes Field of V'mw

f/12.9 0NF), f/30 (P) 160, 66 ercsec 2

Magnitude

5-28 my

Magnitude Range Wavelength Range

9-28 my 1150-11,000 Ang.

Range

Wavelength Range GODDARD

1150-6500 Ang.

HIGH-RESOLUTION

SPECTROGRAPH

FAINT-OBJECT

SPECTROGRAPH

Weight Dimensions

700 Ib (318 kg) 1

Weight Dimensions

680 Ib (309 kg) 1

Principal Invesligator Contractor

J.C. Brandt. NASA/GSFC Ball Aerospace

Principal Investk:3ator ContractoR

R.J. Harms, ARC Martin Marietta

Apertures Resolution

2 arcsec2target, 0.25 arcsec2science 20(X)-100,000

Apertures Resolution

0.1-4.3 arcsec 2 250; 1300

Magnitude Range Wavelength Range

17-11 rnv 1060-3200 Ang.

Wavelengtt_ Range

HIGH-SPEED

WKJht

Magnitude

Range

PHOTOMETER

19-26 mv 11(X)-8(XX)Ang.

FINE GUIDANCE

Dimensions

600 Ib (273 kg) 1

Principal Inves'dgator Contractor

R. Bless, U. of Wisconsin U. of Wisconsin

Apertures Resolution

0.4,1.0,10.0 arcsec 2 Filter-defined

Magnitude Range Wavekmgth Range

< 24my

SENSORS

Weight Dimensions Contractor

485 Ib (220 kg) 3 Perkin-Elmer Corp.

Astrometfic

Stationary & Moving

Modes Precision

Target, Scan 0.002 arcsec 2

Measurement

10 stars in10 min

Speed

1200-7500 Ang.

Field of V'mw

Access: 60 arcmin 2

Magnitude Range

4-18.5 mv

Wavelength Range

4670-7000 Ang.

Detect: 5 arcsec 2

1 Dimension

=

3x3x7 ft (0.gx0.gx22 m)

2 Dimension

=

Camera - 3.3xSx1.7 ft (lxl .3x0.5 m) Radiator - 2.6x7 ft (0.8x22 m)

3 Dimension

=

1.6x3.3x5.4 ft (0.5xlxl.6

m)

1-3

Next

is the

that

equipment

house

power,

section,

computer,

a ring and

of bays

communica-

tion equipment. At the rear, the aft shroud tains the scientific instruments.

con-

The

10 ft

light

shield

and

forward

shell

are

(3.1 m) in diameter; the equipment section aft shroud are 14 ft (4.3 m) in diameter.

gular

boxes

Wide

Field/Planetary

Optical

The Optical mirrors,

Telescope

support

structure.

and

The

WF/PC

and

tions

but

concentrate

objects. quarters,

Assembly

incoming

baffle

is reflected

that

travels

by the

secondary

primary

mirror,

of the primary

fine

called

the mirrors image

1.1.3

focal

1.

plane,

which

sensors

receive

the

design,

focal

length

length,

eter.

that

a

makes

aberrations

sensors

in

plane

optical

axis,

instrument mounted See

structure

can also

aligned

behind

the

and the

three

radially

Figure

consists

of

and a photom-

ence instruments by measuring precisely. Four of the instruments a focal

act as sci-

star locations are housed in with

primary guidance

(perpendicular

the

main

mirror.

One

sensors

are

to the others).

1-2 for the scientific

High-Resolution

instruments.

the

High-Speed

Object Camera Spectrograph (FOS), Spectrograph Photometer

onto

of

one of two sets

mode, mode,

other

photographic

in two modes:

which

of the

of view,

within

sensitive

operates

Planetary

will view

7.2 arc-

sky, and

which

will look

such

at narrow-

as planets

or areas

galaxies.

The CCDs information

record the incoming light, and the is transmitted to earth as electronic

signals

reformed

and

The

FOC

reflects

pathways.

The

or through

into images.

light down

light, after

devices

objects

faint

long

one

passing

of two optical through

that can block

to see background

(FOC), the the Goddard (GHRS),

(HSP)

are

and rectan-

1-4

objects,

exposure

Spectrographs about

source.

filters

out light from images,

enters

The

be built

up over

image

is trans-

total

transmitted

atomic

to earth,

the incoming

wavelengths, the

spectrographs wavelengths lengths.

can

The

data,

separate

its component tion

images

times.

lated into digital then reconstructed.

there The Faint Faint-Object

types

a detector. The detector intensifies the image, then records it much like a television camera.

of instruments

The guidance

different

func-

is

with

Instruments

two spectrographs,

similar

is aft instru-

is a Cassegrain

WF/PC

er fields

bright

first complement

have

on

of extremely

The

Wide-Field

2.

in the

plane.

two cameras,

FOC

quadrant

min 2 sections

12.2 in.

the scientific

to reduce

a

light

a hole

physical

plates.

For The

the

each

equivalent

is reflected

Ritchey-Chretien,

The Scientific

is 3.3 x

The WF/PC splits the light image into using a four-sided pyramid mirror,

focuses

mirror

mirror,

telescope's

hyperbolic

The

m) primary

Here

a smaller

plane down

light.

through

system

of two

focal

the light

guidance the

into

variation, the

to the

means

"folded"

(2.4

mirror

The optical

which

travels

Then

mirror.

and

light.

light

to a secondary

(0.3 m) in diameter.

consists the

stray

(WF/PC)

of four sensors. The sensors are charge-coupled detectors (CCDs) and function as the electronic

and

absorbs

by a 94.5-in.

then

ments

Assembly

trusses,

The

tubular and

Telescope

Camera

5 × 1.7 ft (1 × 1.3 × 0.5 m).

then 1.1.2

3 x 3 x 7 ft (0.9 x 0.9 x 2.2 m); the

revealing

composition

Hubble

light

Space

and

into

informaof the

Telescope's

light two

can detect a broader range of than is possible from earth because

is no atmosphere Scientists

can

composition,

temperature,

lence

of the

stellar

light,

all from

spectral

to absorb

certain

determine

the

pressure,

atmosphere data.

wave-

chemical and turbu-

producing

the

GODDARD

HIGH RESOLUTION

SPECTROGRAPH

BENCH

WIDE RELD/PLANETARY PICK-OFF __

_

CAMERA

MIRROR

DETECTOR

oPT, A.,.s ENTRANCE

ENTRANCE

APE RTURE

MIRRORS

J

PYRAMIDAL MIRROR

C4X_ING

HEAD

FAINT OBJECT CAMERA -- OPTICAL

INCOMING

LIGHT

BENCH

OPTICS

PATHWAY

-_

_LOAD

STRUCTURE

Figure

ASSEMBLY

1-2

ASSEMBLY

The Scientific

1-5

Instruments

(Page 1 of 2)

APERTURE

HIGH SPEED PHOTOMETER - ELECTRONICS BOXES DETECTOR ELECTRONICS

ASSEMBLIES

SYSTEM CONTROLLER POWER CONVERTER AND DISTRIBUTION REMOTE INTERFACE UNITS EXPANDER UNIT SIGNAL DISTRIBUTION

UNIT

SUBSYSTEM

ELECTRONICS

REGISTRATION

CONNECTOR

FITTING 'C'

BASEPLATE PANEL

FT BULKHEAD

FORWARD

INTE RIOR BULKHEADS

BULKHEAD BOX BEAM

l REGIST

_

FFFrlNG

IMAGE DISSECTOR PHOTOMULTIPLIER OPTICAL PREAMPLIFIERS DETECTOR

A' __

LIGHT ENTRANCE

HOLES

TUBES TUBE SUBSYSTEM

HIGH VOLTAGE POWER SUPPLIES OFF-AXIS ELLIPSOIDAL MIRRORS FILTER/APERTURE TUBES

FAINT OBJECT SPECTROGRAPH -- COMMUNICATIONS HIGH VOLTAGE POWER SUPPLY

F'- ANALOG SIGNAL PRCCESSOR -'_

CENTRAL CENTRAL ELECTRONICS

POWER SUPPLY --_

MICROPROCESSOR

FITFINGS-_

\

--_

/

\ \

MOOULE

/

_

r--

POWE R/SIGNAL CONNECTORS

J

-_(_.c--_---_

"_t_z_---'][-'_"_'_"_:_'_

_

/

OPTICAL BENCH LIGHT PATH _

Figure

1-2

ELECTROMECHANICAL MECHANISMS ENTRANCE PORT ENTRANCE APE RTURE POLARIZER FILTER/GRATING WHEEL

The Scientific

1-6

Instruments

(Page 2 of 2)

The FOS can detect detail in very faint objects, such as those at great distances. The GHRS can detect fine detail in the light from somewhat brighter objects. The FOS can detect light ranging from ultraviolet to red spectral bands; the GHRS detects only ultraviolet light. Both spectrographs operate in essentially the same way. The incoming light passes through a small entrance aperture, then passes through filters and diffraction gratings, which work like prisms. The filter or grating used determines what range of wavelength will be examined and in what detail. Then the spectrograph detectors record the strength of each wavelength band and send it back to earth. The fifth scientific instrument is the HSP. It measures the intensity of starlight (brightness), which will help determine astronomical distances. Its principal use will be to measure extremely-rapid variations or pulses in light from celestial objects, such as pulsating stars. The HSP will produce precise brightness readings. Light passes into one of four special signal-multiplying tubes that record the data. The HSP can measure energy fluctuations from objects that pulsate as rapidly as once every 10 microseconds. From HSP data, astronomers expect to learn much about such mysterious objects as pulsars, black holes, and quasars. The three fine guidance sensors are part of the spacecraft's pointing system. Two sensors lock onto a stellar target. The third can measure the brightness and relative position of stars. These measurements, referred to as astrometry, will increase the accuracy of celestial coordinates.

four-foot mast that supports a retractable wing of solar panels 40 ft long and 8.2 ft wide. The arrays rotate so the solar cells face the sun as much as possible. Each wing's solar cells absorb the sun's energy, and the array electronics convert that light energy into electrical energy. This energy goes to the spacecraft's electrical power subsystem for use or storage. Power is delivered by the batteries, which are charged by the solar arrays. When

during each energy. 1.1.5

1-7

the arrays

cannot

shadow collect

Computers

systems and with ground control. The Scientific Instrument Control and Data Handling (SI C&DH) unit controls the Sis, receives and formats science data, and sends it to the communications system for transmission to earth. 1.2

THE HUBBLE PROGRAM

SPACE TELESCOPE

The Hubble Space Telescope project is a multi-phase NASA program aimed at orbiting a large observatory in space for use by the international astronomical community. The program has five distinct phases: •

Development, HST.



Launch and deployment of the completed Space Telescope. Verification of the system and scientific functions of the HST.

Solar Arrays

The Space Telescope solar arrays will provide power to the spacecraft. The arrays are mounted on opposite sides of the HST, on the forward shell of the SSM. Each array stands on a

orbit,

into the earth's

There are two computers in the Hubble Space Telescope. The data management subsystem, through the DF-224 computer, handles data and command transmission between the HST

• 1.1.4

the HST moves

assembly,

and testing



Operations employing tific instruments to about the universe.



Maintenance of the spacecraft ensure and extend its scientific

of the

the HST and its scienproduce information as needed mission.

to

Coordinating

the overall

program

AL.

Marshall

Center,

is working

where

son Space

with

the HST

Center,

at George C. in Huntsville,

during

phase;

the

the

contributing Space

Telescope

conduct team

strument tractors and

the telescope's

as Mission

tractors

who

and

operation

Agency,

vital

components; Institute,

contributed

principal investigators, that created the five

will

Goddard

; and

con-

ments,

Company

many

The

Development

Hubble

subcon-

Telescope

project

over 50 years of inquiry and study bility of an orbiting observatory mers. Led by NASCis Center, astronomers worked

development

and

its scientific

Congress shall

Space

Sciences

and

Lockheed Danbury,

ment.

Hubble

Space

Hughes

built of much

Danbury

sensors

astronomers,

called

Center,

in Greenbelt,

and

and instru-

their

subcontractors

organi-

appear

instruments Office

of

Space

&

Space

Perkin-Elmer

Corporation,

prime

Telescope

Company,

contractors project

for

project

or supervised

Systems,

and

building

the

components,

developers to 1-2

in

subcontract

Inc.,

and the

ref.

Chapter

1-8

5.

separate and

equipment

subcontractors

Lockheed.

Sealed

Instrument Teams Principal Investigator

built

the

in

a sterile

Development

Team Subcontractor

E D. Macchetto European Space Agency

Domier Corporation British Aerospace Mab'a-Espace

Faint Object Spectrograph

R J. Harms, Applied Research Corp.

MartinMarietta Corporation

Goddard High Resolution Spectrograph

J. C. Brandt, Goddard Space Flight Center

Bail Aerospace

High Speed Photometer

R. C. Bless, University of Wisconsin

Space Astronomy Lab. University of Wisconsin

Wide Field/ Planetary Camera

J. A. Westphal, California Institute

JetPropulsion Lab

of Technology

is

sent the

Faint Object Camera

are

develop-

of the equipment

Optical

for

who

After

Instrument

under

contractors and

space

development

of

instruments 5-2.

Table

since

list

Telescope in Table

in 1977. Mar-

and

NASA

to Marshall

Lockheed

guidance

Space shown

equipment

Applications.

CA, and

development

] Now

the

CT, are the joint

responsible

of a large

and

Missiles

Sunnyvale, the

of

the

and sec-

investigators

the team

complete

various

Flight have

instruments

the design

Telescope

auspices

into the possifor astrono-

the program

administered

of the the

authorized

represents

Marshall Space and contractors

on the

telescope

built

to this program.

Phase

Space

and primary

led development teams scientific instruments.

Flight

principal

zations, and Table 1-2. The

1.2.1

Space

test-verified

MD, is responsible for the development in-flight testing of the instruments. The

in-

prime

of international

the

as principal

& Space

Corp.1

is

international

observers;

Missiles

A group

which which

an

including

ondary mirrors, and the fine and other optical subsystems.

Space control

Space

and

Perkin-Elmer

designed

(P-E)

organized

Lockheed

Telescope.

OTA,

operations;

developers

Space

Perkin-Elmer

verification

of astronomers

and

John-

Science

science

completed

assembled

will be launched; will operate

several

then

Space

which

European

the

SSM,

Kennedy

Control during deployment; Goddard Flight Center, which will be the ground center

entire

as the project

management center is the staff Marshall Space Flight Center,

clean room, the entire Space Telescopewas assembled, then tested under launch, liftoff, and spaceconditions.

1.2.2

Launch-and-Deployment

During

the launch-and-deployment

Kennedy

Figure 1-3 shows the assembledSpace Telescope in Lockheed's clean room prior to final pre-shipment testing.

Phase

and

Johnson

responsibility Kennedy

for the Space

will place

cargo

bay of the

launch

activities.

phase,

Space the

Centers Telescope

Space

Space

the

and

in the

run

Space

the

program.

Telescope

Shuttle

When

both

share

all pre-

Shuttle

lifts

off, Johnson Space Center's Mission Control, Houston, TX, will take over control of flight.

Johnson

astronauts

has

trained

to perform

the

in the

Shuttle

extravehicular

activities

designed specifically for the Space Telescope, such as manually turning on the spacecraft's internal power. During the Shuttle JSC Mission Control will work with crew and

the Space

trol Center Center.

Once

in orbit,

deploy the

the

by the

Space

The

manipulator

the HST in space.

STOCC

and

for a depiction 1.2.3

Figure

The

1-3

tests completed,

the Space At

Space

more date.

tests

the

to Kennedy Space

to ready

and NASA

Telescope

the spacecraft

Space

flew

Center.

underwent for its launch

Hubble systems

space.

This phase

Running

Flight developed

Telescope

moves

operational orbital ations,

and and

and

tested,

the

into the program's

phases: scientific in-orbit

launch

and

verification, maintenance.

Hubble

Space

four major deployment, science

oper-

work After the mal

1-9

will use (RMS)

After

a check-

Control,

the

Shuttle will reSee Figure 1-4

its first Orbital

by Marshall tests

Space on the

the spacecraft's

func-

30 days

in

Verification Flight

Cen-

HST

subsys-

systemic

ability

in space. verification,

Center,

through

crew

will undergo

over

is called

internal

tems will ensure

Scientific Once

Telescope

testing

and is controlled

to function

will

Phase

Space

tional

ter.

crew

of the sequence.

Verification

The

Assembled

Lockheed

Telescope

Kennedy,

Telescope

Flight

system

Mission

telescope will be released. The main nearby in case it is needed.

Con-

Space

Shuttle

Telescope.

remote

arm to position

Operations

at Goddard

the

Space

Shuttle

out

Telescope

(STOCC)

operation, the Orbiter

tests

run

by Goddard

Space

will put

all science

instruments

to ascertain

that

instruments

the

and conform to NASP_s specificatioris. verification of all scientific instruments, Hubble

Space

operational

Telescope phase.

will enter

its for-

Figure

1.2.4

Operational

1-4

Space (From

Telescope Deployment Left to Right)

Sequence

The

Phase

Space

(STScl), tific During the

the post-verification

Hubble

Space

operational

Telescope

tem will use the following

phase,

observatory

complex

Tracking and and domestic The

Space

Data Relay satellites

Telescope

The trol

network

ground

prised of the following: -- The STOCC, which

controls

operations through the ations Control Center Goddard

of

(TDRS)

system,

programs

for the

Institute

where

Space

scien-

Telescope

sys-

network:

Satellites

Science MD,

will be planned STOCC

operations. The HST spacecraft The NASA communications

Telescope

in Baltimore,

commission

Payload Oper(POCC) at

of the

The

STOCC

tions. center

primary

has

center

of ground

minute-to-minute

spacecraft

STOCC schedules, ence observations.

when plans,

two

and

required, supports

subordinate

conand

the

all sci-

organiza-

The POCC is the ground-based nerve for the HST. It sends all communication

to the spacecraft and The Science Support between

1-10

is the

It provides

the

POCC

monitors telemetry data. Center (SSC) is the link and

the

Space

Telescope

Science

Institute.

The

SSC

supports

scientific

operations, from quick checks of incoming for accuracy to processing and managing completed

data

The

is the scientific

STScI

is responsible selecting assist the

package.

for all operational

and analyzing

collected

by the

teams

an agenda

objectives. will

send

guide

at the

to the

HST DF-224

the

from

pointing

that

target

position, This

it could

on a dime

subsystem.

system

than

the

diameter

Any

of the

five

away

of the coin.

sensor

then

will

target.

That

information

or sensor

Science

to the

teams

science

ments

at and more

Maintenance

ments

percent

mentation unit.

on

the

SI C&DH during a the data

for distribution

Figure

a second that

slightly theless,

back

up each

equipment

most other

in function. There when equipment

of the

NASA

generation

could

Space

already

is con-

of scientific

replace

the

will be exchanged

instru-

original

group.

in orbit,

not on

ground.

Responsibility Marshall, but nance

for this phase currently Goddard will oversee

lies with mainte-

eventually.

During

a

Shuttle

will

Space

bring

Telescope's

the Shuttle stow HST

1-6).

maintenance

and

of the scientific because

instru-

or identical

part, Figure

mission,

up

the

equipment,

orbit,

and

Space

match

grab

the

the

HST with

RMS arm. After ground commands antennas and solar arrays, the arm

place

the

horseshoe-shaped

on the HST has a backup

For example,

ments

lifetime

will be sent

Phase

of the

the

For example,

sidering

bay. The Ninety

to extend

Telescope.

will 1.2.5

and

will be replaced

1-5.

or a fine

to the

Institute (see

fine

the

then sent to the STOCC transmission. From there

will go to the

on Target

years. Maintenance missions will to replace equipment or instru-

Instruments

data

Locks

after several be scheduled

not waver

collect

HST

prostars,

Figure

1-5

the HST batteries

of light squarely

instruments

specified

instrument

HST

Figure one example,

telescope

See

guidance

computer, scheduled

data

is so precise

and

scientific

catalog

computer

The

hold a beam

600 miles

star

the

/

Space

the guide

point

it

satelof two

using

will lock onto

itself.

that

spacecraft,

and

a target,

points.

The

will

targets

selects

coordinates

sensors

by the

STScI

celestial

STScI

by STScI's

by the

guidance

stable

Telescope.

designated

will maneuver

the

the

data

via the TDRS communication HST will use the coordinates

as reference

and,

It

and for

astronomical

working

targeting

stars,

vided

center.

science

Space

of specific

When

Telescope lites. The

the

Hubble

astronomy

have

operations

observers. Teams of astronomers Institute staff in planning, selecting,

observing,

The

data the

platform

Space

latched

HST

Telescope

down

onto

a

special,

in the Shuttle and

in a carrier,

the are

cargo

replacement depicted

in

1-7.

instru-

they overlap

may be times, nonewill need repair. As

1-11

All support equipment and ments are located on the HST a space-suited

astronaut.

The

scientific instrufor easy access by bays

have

hand

STARLIGHT

TRACKING AND DATA RELAY SATELLITE SYSTEM (TDRSS)

DOMSAT

SPACE SHUTrLE

S

....

TDRSS GROUND STATION

Figure 1--6

HST Network

Collecting

Data

and footholds for the crew, and doors opening onto most equipment and instrument compartments. The crew will make repairs while the HST stands in the cargo bay. Then the Shuttle will release the Space Telescope to orbit again.

The Shuttle also can move the HST to a higher orbit, called reboosting. This may be required due to the atmospheric drag on the HST, which is slight but enough to cause the spacecraft orbit to decay and eventually bring the spacecraft back to earth.

Figure 1-7

HST Berthed

in Shuttle

Bay

Eventually, maintenance missions may be performed on Space Station Freedom using an Orbital Maneuvering Vehicle that brings the HST to the station.

,)

Section THE HUBBLE The

Hubble

and

observes

by the

Telescope

specific

Space

spacecraft



Space

three

The Support structure

provides services tion, and control. •

The Optical which collects ing light scientific



placed

(SSM), other

plane

instruments,

along

plane

Peripheral

the

all

and

four

maintenance

by the

controlled

by

the

in an

and

one

of

the

circumference

Data

Handling

fine

guidance

craft;

two

sensors solar

and

ground

four

unit

Scientific

2-1 Space

The Space

tory,

point

re-energize

antennas

operation the spacethe

send the

Three HST's

and

Space

receive

Telescope

control.

Hubble

shows

the

configuration

of

the

Telescope.

Telescope

performs

observatory

reflecting

the

Telescope.

precisely

arrays between

Figure

ground

supports

of the Space

communications

(OTA), incom-

housed

equipment

and

batteries;

communica-

use

and

(SI C&DH).

an outer

structure

Control

The

systems

for

SYSTEMS

Instrument

and

focal

spacecraft,

Institute.

such as power,

in the focal instruments.

section

earth

systems:

Module the

TELESCOPE

selected

Telescope Assembly and concentrates the

Five scientific aft

Science

houses

the

targets

interacting

System

that

orbits

celestial

Telescope

has

SPACE

2

with

telescope.

powers,

The

points,

a

SSM,

and

very much

like a

medium-sized like an observa-

communicates

with

MAGNETIC HIGH

GAIN

ANTENNA

SSM S" LL SECONDARY MIRROR

SS

MIRROR FINE

GUIDANCE

& MAIN

CONTROLSENSOR(3) OTA

FOCAL

RING

OPTICAL

EQU

BAF;LE

_ _

NG

_.._,_"_

TRUSS

_

RADIAL

Sl

I

_

.,.,,..,,(_Sz::_y._---_

MAIN

It J

_/I

I

_/_"_

BAFFLE

I

sOTATEIo QUIPMENT

SSM

AFT

SHROUD

FIXED RATE

HEAD GYRO

STAR

TRACKER

&

ASSEMBLY

Figure

2-1

Hubble

U

_'t

MODOLE(,

__

U"'

J"

STRUC','URE •

-,

_

t_((II\_

__ _ { ..-"_

\

(4)

_{_

"_----__/

X

TORQUER

_

_ L

X

PLANE

BAFFLE

METER

CENTRAL_

_-_'_"-_

(2)

Space

2-1

Telescope

Configuration

,_

SOLAR

ARRAY

(2)

the telescope Light

assembly

from

the observed

the telescope tific for

and

target

is recorded.

the

then

light

to on-board

either

via the spacecraft

computers

is stored

or sent

communication

to

system,

Space

while

Telescope

The primary telescope,

parallel gain

will make

the earth.

97 minutes.

tain its orbital the

The

Support

position end

to end. array

masts

The

masts

(V3)

(see

HST will point and maneuver rotating around two of the axes.

one

or-

will main-

three

axis, V1, runs through

the solar

antenna

spacecraft

along

MODULE

It also

Module

provides

the

that houses the Optical Teleand the scientific instruments.

contains

the electrical

thermal

control,

for the entire include:

power,

data

man-

and communications

Space

Telescope.

Design

its observations

It will complete

The

SYSTEMS

Systems

external structure scope Assembly

systems features

orbiting

bit every

THE SUPPORT

agement,

for analysis.

The

2.1

through

where goes

processing,

passes

of the scien-

information

earth,

an observation.

into one or more

instruments,

This

to ready



axial planes. the center

other

(V2)



of

two axes

and

Figure

the high 2-2).

outer

structure

Rotating

reaction

torquers

to orient

SOLAR

ARRAY_

V2

wheels and



A ring of equipment-section tain electronic components,



Computers and handle



Reflective



Outer

ies, and

doors,

of

Figure

2-3.

these

The major are the:

and

component

designed

in-orbit

are

subsystems

systems

protection

rails

during

features

Structural and Instrumentation

bays that consuch as batter-

for thermal

use

HST

power

the spacecraft

latches, to

magnetic the

equipment

to operate data surfaces

Some

• •

to provide antennas

communications

shells

and

stabilize

Two solar arrays Communications

astronauts nance

+Vl

of interlocking

• •

The

to new targets by three spacecraft

An

for

mainte-

illustrated

of the

in

SSM

mechanisms subsystem and communications

sub-

system + V2

Vl

V3

Figure

References

2-2

Hubble Axes

to these

pointing

instruments

position in orbit.

the solar

Space

axes

are

Telescope

used

by the

to aim at a target arrays,

or change

HST

in space,

orientation



Data



Pointing



Electrical



Thermal



Sating

A

team

control

subsystem subsystem

power

subsystem

control

subsystem

(contingency)

of

designed structure. Chapter

2-2

management

and The 5.

contractors

subsystem

and

subcontractors

built the components for the full list of team members is in

bAIN ANTENNA EQL HANDRAILS

DIGITAL INTERFACE

DOOR

LIGHT

SHIELD

REACTION WHEEL

ASSY '_NETIC TORQUERS

COMMUNICATION

SYSTEM

COMPUTER

LOW

SOLAR

ARRAY

GAIN

ANTENNA

UMBILICAL

LATCH

IF

PIN

SUN LIIPMENT

SENSOR(3)

SECTION

3ATTERIES AFT

AND

SH ROUD

CONTROLLER

ACCESS

Figure 2.1.1

Structural

2-3

Design

DOOR

Features

of the Support

and Mechanisms

painted

The outer structure of the SSM is composed of stacked cylinders, with the aperture door on top the aft bulkhead

er are the light SSM equipment bulkhead. &

Figure

2.1.1.1

are made

Company

2-4. Figure

Telescope

on bottom.

Fitting

togeth-

shield, the forward shell, the section, and the aft shroud/

They

Space

by Lockheed

and

are

2-5 shows

Missiles

identified

the Hubble

in Space

Aperture

material,

black

Door.

The

aperture

door, covers

the opening to the telescope's light shield. The door is made from honeycombed aluminum sheets. The outside is covered with

2-3

to absorb

and stray

opens

to a maximum

from

closed

position.

the

the

inside

is

light. of 105 degrees

The

telescope

aper-

ture allows for a 50-degree field tered on the V1 axis. Sun-avoidance

of view censensors on

the

to close

door

provide

before

scope's

optics.

The

the sun is within finishes closing

Space

ter

(STOCC) within

door

This

Telescope

door-closing

damage begins

can

takes

the

the

closing

no

Operations

telewhen

20-degree

for

more

Control

override

mechanism the

warning can

35 degrees of the V1 axis and by the time the sun reaches

of V1.

The

fall

ample

sunlight

20 degrees 60 seconds.

10 ft (3 m) in diameter,

Module

The door

door

assembled.

approximately

Systems

solar-reflecting

Subsystems

and

CHARGE

the

than

Cen-

protective

observations

limit.

An

example

that is

LIGHT APERTURE

MAGNETIC TORQUER

HIGH

SSM

GAIN

(4)

ANTENNA,

FORWARD

SHELL

! SSM

EQUIPMENT

SECTION

SSM

AFT

SHROUD

Figure

2-4

The Structural of the SSM

observing

a bright

or edge,

of the moon

2.1.1.2

Light

object,

Components

using

the

to partially

Shield.

The

dark

block

HST

limb,

the light.

light

shield

blocks out stray light. It connects ture door and to the forward shell.

to the aperOn the outer

skin on opposite

to secure

solar

arrays

sides

and

they are stowed. plates,

large

around The Space The

and

plates

diameter

and

there

magnesium,

with

covered

waveguide, are

foot

with

by a thermal

has ten light baffles,

rails

restraint

on the

HST.

from

painted

to suppress

2-5

stray

aperture

door

2.1.1.3

Forward

central

corrugated-skin blanket.

Figure

and

HST

Assembly

light.

Figure

light

shield.

2-6

shows

the

an internal

It is machined

a stiffened,

bay.

low-gain Hand

operating

10 ft (3 m).

the

cargo

forward

is 13 ft (4 m) long, of

the shield

Shuttle

the

communications

for astronauts

extend

will secure

magnetometers.

the shield,

shield

the

are scuff

that

of the spacecraft.

trunnions

within

I;::_BII

the when

latches

on struts

supports its

antenna

the surface and

three

supports

barrel

the array

shield

the

encircle

The

Near

metal

Telescope

antenna and

high-gain

plates

light

latches

the

30 in. from scuff

are

telescope

Internally flat black

2-4

mirror.

section

Shell. of the

assembly The

solar

The forward structure

main

baffle

arrays

and and and

shell is the houses

the

secondary high-gain

2.1.1.4 bays

APERTURE

Equipment encircling

electronic

DOOR 7

vehicular in-orbit

APERTURE HINGE

SUPPORT,-_

/---APERTURE

I\

INTEGRALLY

INTERNAL BAFFLE

_HINGE

_

_ J,."_

t

and

section

/-.!_

_

__1 __"---'-MAGNESIUM I=

MONOCOQUE

_J,_

__

SKIN

ATTACH

//

RING _

_

M

_"

_

pins

the

L--HGA

LATCHES

and

when

SUPPORT

Aperture Door Light Shield

the forward

stowed,

and

are latched

flat against

shell and the light shield.

Four

outer

skin has two grapple

the high-gain

antenna

remote manipulator SSM. The forward used

drives,

fixtures, where

hand

and

The

forward

foot

shell

(3 m) in diameter. num plating, internal outside assembled

holds

(see

cargo

Figure

is 13 ft (4 m) long It is machined reinforcing

stiffened panels. The to assure clearance Thermal

rings for

blankets

Going

position,

aft

control

Bay 9

--

Reaction

wheel

Bay 10

--

Scientific

Instrument and

support

Data

management

Communications

Bay 6

--

Reaction

Bay 7

--

Mechanism

the

contents

shows

the

of each

Handling bay

Bay 4 -- Power trunnion support

--

2-8

assembly

Data

Bay 5

contain:

subsystem

trunnion --

clockwise

the bays

unit equipment bay

wheel

assembly

control

location

unit

of the

bays

and

bay.

/--

next to

system can attach to the shell also has a trunnion,

with external

inside.

scuff plates.

apart shell.

the Orbiter

to lock the HST into the Shuttle

and

to support

mag-

netic torquers are placed 90 degrees around the circumference of the forward The

two bays

Pointing

Figure antennas,

the forward contains 10

--

Bay 2 through Unnumbered

RING

2--6

performing

is a dough-

Bay 8

Bay 1

& SA

LATCH

Figure

and

+ V3 (top)

Unnumbered

_

_-SA

crews

extra-

repair. (SSM-ES)

Control Unit

__

spacecraft.

during

barrel that fits between aft shroud. The section

b] LSAIFS

the

of the

DOOR

from

LATCHES-'-_

by Orbiter

bays for equipment

//--APERTURE

trunnion

STIFFENEDsKIN__HGA _

run

serviced

activities

of storage 90%

DOOR

/HINGE

I \

to

equipment

equipment

A ring

contains

maintenance

nut-shaped shell and

DOOR

SSM

components

This includes

The

Section.

the

FORWARD

SHELL

REINFORCtNGRINGS

_

/

/

7

_

;_

STOWED

_

_R(_L_ETR_

bay,

2-7).

and

from

STOWEO

10 ft alumi-

rings

and

SOLAR ES/FS INTERFACE RING _'INTEG

are on the the OTA cover

the

exterior.

2-5

SKIN

Figure

2-7

RALLY

STIFFEN

ED

PANELS

SSM

Forward

Shell

ARRAYS

-It_

PJ° "L

-----------,,_

1,11

_t

O

4

_n

/"

__

_t

-,-_. ]L IL

--I

_T

oo

L c_

+¢ t,,.

i.o +

2-6

Each

bay

is shaped

outer

diameter

diameter,

like

(the door)

panels

attached

barrel.

Eight

bays

minum

doors

mounted

9 have

to an

have

thermal

covering

hold

m). The

flat

inner

2.1.1.5

Aft

shroud

houses

ing

the

axial

panel

section. doors

crew

are

ference nate

Bays doors

rails

located

The

plane

The

structure instruments.

used

during

honeycombed

radial

aluminum

The

shroud

gas purge

and system

of the scientific vents

used

3REW

equipment

and instruments

foot the

restraints length

Interior

for

and

lights

containing

contains the

HST

low-gain It is made

aluminum support bulkhead instruments

to expel

the gases

prior

PIN SUPPORT

FLIGHT

SUPPORT

2-9

BEAM SYSTEM

SSM Aft Bulkhead

ft (3.5 m)

con-

Orbiter,

and

in-orbit

2.1.1.6

Mechanisms.

ture are functions.

mechanisms used The mechanisms



Latches



Hinge

to hold drives

erect

PINS

Shroud

and

the

SSM



Gimbals dishes



Motors

There

and three

four door.

a

high-gain

contamination to launch.

are light-tight;

There

All i.e.,

2-7

hinges actuator.

latches:

latch

a rotary-drive support

and

door

and

and

antenna

and

latches

and

antennas

four

and

and are driven

arrays

high-gain

the hinges

arrays,

various

solar

aperture

the

arrays

nine the

and

struc-

antennas

move

the

to perform include:

the

and

to power

They

linkage

to open

to

are for

Along

antennas

the arrays

to rotate

antenna atof two-inch

structurally

FSS

circum-

beams.

used to prevent

LAMINATE PANELS

the

the

panels

ANTENNA )MB

Figure

can illumi-

umbilical

and

_AIN

AIDS

STIFFENED

UMBILICALS

VENTS

the scientific

the

IRALLY PANELS

SKIN

the can

The rear bulkhead.

thick

ES/AFT SH ROUD INTERFACE RING

ELECTRICAL

outside of astronauts

and

the

launch/deployment

maintenance. taches to the

SI DOORS

REINFORCING RINGS

The

a stiffened skin, internal panels and rings, and 16 external and internal

between

focal

SI DOORS

contain-

bars for support. It is 11.5 14 ft (4.3 m) in diameter.

nections

OTA

aft

On the so Shuttle

along

bulkhead

the

2-9).

A for-

and

the compartments

aft

in

those

pro-

instruments during maintenance or removal of an instrument. The shroud is made of alumi-

longeron long and

Figure

with

+ V3

6

aft shroud

of the shroud.

num, with reinforcing

to interfere

concentrated

(see

AXIAL

enclose the of the bulk-

Bulkhead.

between

and change Hand

enter

RADIAL

sensors and the Wide Field/ are housed radially near the

equipment shroud are easily.

plane

alu-

wheels.

scientific

point

remove

and

the focal

connecting

can

in place.

Shroud

three fine guidance Planetary Camera

light

aluminum

with equipment. stiffened

OTA

four

no stray wavelengths

bays

honeycombed

for the reaction

the

the

than the inner

ward frame panel and aft bulkhead section. Six mounts on the inside head

with

and 5 ft (1.5 m) long. The and stiffened aluminum

frame

viding

greater

3.6 ft (1 m) to 2.6 ft (0.78

are 4 ft (1.2 m) wide section has machined

and

a trapezoid,

for

one

the

for

release

the

using

by a stepper

antennas, aperture a four-bar

motor

called

actuator.

are

three antenna,

also

hinge and

operate

drives: one using

one

for the a

for

each

door.

The

rotary-drive

Both hinges and latches have hex wrench fittings so an astronautcan manually operate the mechanism to deploy the door, antenna, or array if a motor fails. 2.1.2

Instrumentation

and

antennas from honeycomb aluminum and graphite-epoxy face sheets.Figure 2-10 shows the antenna dish.

Communications

Subsystem

HIGH

GAIN

ANTENNA

The

instrumentation

and

communications

sub-

system between

provides the communications loop the HST and the TDRS satellites,

sending

and

receiving

messages,

and

data

through

the

high and

nas

and

passing

the

information

management refer

subsystem.

High

to the effectiveness

commands,

low gain

anten-

to the

data

TWIN

gain and low gain

of the antenna,

AXiS

J

GIMBALS

I

higher

J

being

more

have

The

effective.

larger

The

signal-collecting

communications

ple-channel systems

sages.

The

and

transmitting

science

and

data

data

and

mes-

can

send

data

on

either

Figure

data

under

Each

or taped

antenna

high-gain

antennas

nications

links

Antennas are

to

(HGA).

the

relay

The

primary

science

two

two

frequencies:

MHz

(plus

low-gain

97-minute are not used.

Each

during

the high-gain

the

low-gain

each

antennas

antennas

antenna

antenna gimbal the

mechanism

antenna

General

is a parabolic

mounted

on

and

100 degrees

Electric

a

ple-channel

designed

electronics and

system.

aft bulkhead

MHz

or

10 MHz).

(LGA).

ground

The

commands

data using

the multi-

They are on the light of the

spacecraft,

set

a

2300

MHz.

The

to

tured

by Lockheed,

direc-

made

2255.5

receive

engineering

stability transmit

apart. Each antenna is a spiral frequency ranges from 2100 to

with

in either

and

HST

antennas

Antennas

access

Anten-

180 degrees cone, with

reflector

mast,

with

is not as

position. the

The

or minus

antennas

and transmit

are

of sight.

Low-Gain

shield

two-axis tion.

When

extended,

high-gain

(dish) rotate

orbit.

maximum

line

affect

over

2.1.2.2

minutes

will not

the

using

position

Accuracy

of a given

to

about

90

Antenna

to a fixed error.

commu-

data

operation,

0.01 arcsec

thus,

the

normal

pointing

and,

single-channel access system. When in sight of TDRS satellites, the antennas can transmit

during

can point

na movement

2287.5

ground

The High-Gain

crucial for communications as for pointing the telescope, where the OTA must point accurately to within

High-Gain

2-10

a one-degree

contingen-

cy conditions.

2.1.2.1



or

Single-access

as it is gathered,

engineering

A

(broad-

system

simultaneously.

science

f

multi-

access

engineering

channels

transmits

provides

single-channel

for

antennas

areas.

multiple-access

commands

gain

subsystem

and

cast)

both

high

the

2-8

is placed when

in orbit

the high-gain

low-gain

antennas,

can be used while or retrieved, antennas

manufacthe HST

or in emergencies cannot

be used.

2.1.3

Data

The

Management

data

receives

Subsystem

management

subsystem

communications,

commands from the tions Control Center, systems

and

the

scientific

stores, The



DF-224

computer

• •

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• •

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except OTA.

and

sends

the

subsystem

located

3.

Scientific

from

4.

System

2.1.3.1

unit

and

sends

sent

to the

HST

signals

subsystem

Computer.

by Rockwell

types

tions

into

functional

solar

arrays

Autonetics,

The

of

cessing

systems

(MU),

units

the power stored

to handle

these

central

two as backup; (IOU),

the

It has

is three

with up to 48,000

input/output

orient

monitor

written

(CPU),

for onboard

antennas.

configuration

units

used

sun,

the

specifically

DF-224

is a gener-

(telemetry),

the

point

com-

The computer must format data calcula-

signals

toward

and

The DF-224

computer

radio

programs functions.

in the

four

the

digital

system,

section,

stored

SI C&DH

as clock

engineering computations. execute stored commands,

recorders

equipment

such

is

DF-224 built

units

Commands

2-11

al-purpose

interface

receives

outputs,

the

as

are:

unit units tape

data

or system

diagram.

signals: 1.

such as commands

Figure

it

information

components

in the

data

This subsystem

Then

Received data, status data

puter,

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are

and

Space Telescope and data from

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(DMS)

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section

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Figure

1 of the SSM

.

2-12).

TH COMPRESSION °

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powers

HST timing decodes each

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unit (DMU), made the DF-224. It encodes

messages units,

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HST

units

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all incoming

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commands,

command

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then

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to be executed. MATRIX I CONNECTOR-

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data

management

printed-circuit a backplate

and

unit

is an assembly

boards, interconnected external connectors.

of

through The unit

weighs 83 lb (37.7 kg), measures 26 x 30 x 7 inches, (60 x 70 x 17 cm) and is attached to the door Figure The

of equipment 2-13). DMU

C&DH. come

science

data

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data,

readings

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from

each

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can be stoi'ed

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the

Figure

SI

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engineering/

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Data

interface

units

between other

the

receive

Computer

2-10

from

DIU other

units

are

section.

a subsystem

The

four

and built

and

data

link

interface

and units

management

required, and pass back to the DMU.

to the DMU. in bays

data

subsystem data

the data

unit is in the OTA

for-

evaluation.

management

Each

equipment

only when

also engineered

perform the operations or status information

the DF-224

when

The

the For

diagnostic

Unit.

unit, data

connects

selects

is used

a command

subsystems.

instructions

interface 2-12

(DIU),

via

required.

immediate

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data

also

and

transmission

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format format

provide

HST

unit

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if direct

operational, needs

by LMSC,

Figure

Data Management Configuration

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example, PCU

POWER SUPPLY

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section;

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As a safeguard,

each

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is

two complete dle the unit's "X...__4

units in one; either functions. Each data

part can haninterface unit

is 15 x 16 x 7 in. (38 x 41 x 18 cm)

and

weighs

35 ib (16 kg). Engineering/Science

The

management

tape

recorders

data

that

used

or science to the

ground

can hold up to one Two recorders are

operations;

the third

operations.

weighing

ment

20 lb (9 kg), are

section

2.1.3.5

bays

Oscillator.

highly-stable the

1, 3, and The

central

HST.

It has

provides

pulse,

kg).

backup are mounted ment section.

The

a

required

by

housing

4 in.

and 9 in. (23 cm) long

3 lb (1.4

the

assembly

and

2.1.4.1

sensing

Pointing

oscillator

and

and

a

in bay 2 of the SSM equip-

The

pointing

tains

Space

aligns

the

locked

Control

The four

coarse

on

control

subsystem

Telescope

positional

subsystem

any

is accurate

main-

stability to and

target.

to within

located send

position

a beam

The 0.01

and

remain pointing

arcsec

and

of light on a dime the

maintains

locating

two

HST

to keep

these

stars.

guide

beam

When

realigning

system

selects

new

moves

telescope's

stars

it in the

require and

the

and

same

straying

different

the Space

position

maneuvering position

specific the

sun sensors, and

used

the mag-

assembly,

the

fine

the

guidance

the

reference Telescope

and

devices,

aft shroud,

safemode

that

electron-

8 of the SSM equipment sun sensors measure the

sun.

when

They

also

position

for

to begin

sensors

calculate the

closing

position

sun-orientation

The

the

HST

the

the

modes

magnetic

sensing

magnetometers,

both

light

shield,

that

units

sending

the data

The

system

and

aperture

HST

during

in contingency

rate

the

pointing

pointing

the

line

connected the HST's

assembly

control

to electronic computer.

relative

consists

send unit

relative

of sight

of the

orien-

magnetic

field.

of

information inside

the spacecraft's

system

of two

end

three

underneath the SSM equipnext to the fixed-head star

units

senses

and position

requests guide

until

to

assembly

front

to the earth's

units and

These

consists

the

to the DF-224

measures

gyro

electronic

system on

are

with respect

rate-sensing ment section

by

relative

target

spacecraft,

are sensing

shield

in bay coarse

Sun

trackers. PCS

light

deployment

determine

The

The

of sensors

the rate gyro

sun sensors

of the

initial

Angeles,

hold

gyro assembly,

contingency system. details on these

to the pointing

ics assembly section. The

tation

it could

electronics

mode

trackers,

on the signals

can hold the telescope to that position with 0.007 arcsec stability. If the HST were in Los in San Francisco, without from the coin's diameter.

safemode

It also

operations. (PCS)

to point

specific

five

2-14).

The five types

system, star

special

Subsystem

spacecraft

Figure

pointing

fixed-head sensors.

door. 2.1.4

(see

the retrieval

Sensors.

includes

the DMS computer, called actuators, to

8.

a cylindrical

cm) in diameter

weighing

in equip-

oscillator

timing

spacecraft

includes

netic

recorders,

stored

the

subsystem

of sensors, of devices,

by the PCS are the coarse

is a backup

The

control

types types

both used in the spacecraft See section 2.1.7 for assemblies.

three

12 x 9 x 7 in. (30 x 23 x 18 cm) in dimension

and

(10

engineering

The recorders of information.

or for contingency

Recorders.

includes

be transmitted

in normal

each

Tape

subsystem

to store

cannot

immediately. billion bits

pointing

different and two move

2.1.3.4 data

The

can

to the

bay rate

10.

to the

orbital

plane

control

the

orientation

of the

Space

The

of motion so the of

Telescope.

stars

it is in the

position.

2-11

A fixed-head

star

detector

locates

that

tracker and

is an electro-optical tracks

a specific

star

SUN

SENSORS

MAGNETOMETER

FINE

GUIDANCE

SENSOR

RATE

I

(3)

GYRO

ASSEMBLY

(3) TORQUERS

(4)

COARSE SUN SENSORS

(2)

REACTION

"_

WHEELS

(4)

COMPUTER

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EQUIPMENT SECTION

FIXED STAR

HEAD TRACKERS

(3)

SCIENTIFIC INSTRUMENTS

BAY BAY

7 --

MECHANISM

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8 ----

+ V3

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CONTROL

RETRIEVAL POINTING

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6 --

REACTION

WHEEL

REACTION

WHEEL

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1 FWD

NO.

2 AFT

AND

--

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(RWA)

(2) 9

INSTR ASSY

WHEEL

(2)

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3 FWO

NO.

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10 --

SI CONTROL AND

DATA

HANDLING --

RGA ELECTRONIC CONTROL (ECU)

_- V2

BAY1

--

DATA

MANAGEMENT

COMPUTER

2 - V3

Figure

2-14

Location

2-12

LOOKING

FORWARD

of the PCS Equipment

UNIT

(PSEA)

within

its field

of view.

The three

trackers

are

position

updates. operations

that

computer

offsets

instrument when vers into its initial

the Space orientation.

momentum with magnetic torque. The DF-224 also smooths HST movement to minimize the

calculate

information

position positioning lock onto

teract

with

rate

gyros,

the

before

and

after

to help the fine guidance guide stars. The trackers in-

fine

guidance

at a command

sensors

from

and

STOCC,

vide a reference for targeting. for detail on the star trackers.

See

the

to pro-

Figure

2-15

effects

commands

translates

wheel

coarse sensors

targeting

DF-224

The

Telescope maneuThe trackers also

ground

The

located below the focal plane structure, on the -V3 axis, next to the rate sensor units. The STOCC uses a star tracker as a calibration

of vibration

2.1.4.3 netic

The

torquers,

which

reaction to move

wheels

maintain

also

to

has

two

assemblies

move

the

types and

of

mag-

spacecraft

the

into

and

to move

are oriented

with

only three

assemblies

the

wheels,

section.

transfer

The

HST

wheel

can operate

if required.

in diameter

flywheel

it to

two each

equipment

23 in. (59 cm)

a large

the

The

in a stable

spacecraft.

so that

spin

into position.

braking

are paired,

SSM

use

spacecraft

by rotating

rpm

axes

assemblies

the HST

They work 3000

momentum

of the

optics.

PCS

wheel

momentum

up

wheel

positions.

four

position.

reaction

on telescope

wheel

reaction

the spacecraft.

the

reaction

commanded

The

maneuver

Actuators.

actuators,

into

The

wheel

in bays 6 and 9 Each

and

wheel

weighs

is

about

100 lb (45 kg). See Figure 2-16 for the configuration of the reaction wheel assemblies.

Figure

2-15

FHST Door

three

fine

guidance

The more

detail

later,

of a star. pointing

make

adjustments,

the

guidance

pointing, tional

while

Chapter

the the

angular

accurate sensors

the

third of

This

discussed

most

function

is

Two

Figure2-16

for posi-

stars,

called

PCS

data

Computer.

uses

management

the

The

DF-224 subsystem

Reaction

discussed

in

The

magnetic

the

reaction-wheel

against reaction

_L J_

LI_ :

Wheel

Assembly

pointing computer to

control in the calculate

2-13

tum.

torquers

create speed.

torque

The

to change

torquers

react

the earth's magnetic field. The torque occurs in the direction that reduces the

reaction-wheel subsystem

El ..£2 _'_

a frac-

3.

2.1.4.2

1 ..£2

guide-star

is available specific

El J2

_.f

fine

the target.

perform

in

position

delicate

to within

to pinpoint

measurement

astrometry.

(Aft Shroud

sensors,

measure

They

tion of an arcsecond, of

Detail Open)

The

perpendicular lines.

speed

torquers to

by balancing

provide the

torque

earth's

the momenin directions magnetic

field

The torquers also act as a backup the HST stabilizes its initial orbital during

a system

externally

on

8.3 ft (2.5 ence,

failure.

the

m)

and

Each

forward

long,

weighs

system, when attitude, and

torquer,

shell

except

bays

SSM,

is

around

Before the

in circumfer-

HST. PCS Operation.

pointing

control

To point

subsystem

precisely,

combines

tions of the gyros, reaction wheels star trackers, and fine guidance fine guidance

sensors

provide

from which the Space sitioning.

The STOCC

wheels

to spin,

motion

fine

If needed,

load

the

the

As the HST nears

spacecraft area

has

about

sensors

of the

guide

stars

60 arcmin

take

over

the gyros and cise pointing, HST

the

region

2, the

pointing

0.01

arcsec

which

stand

of the

the

a target guidance with

target.

The

pointing control system can maintain this position, wavering no mgre than 0.007 arcsec, for up to 24 hours

to guarantee

tion exposure hours.

2.1.5

instruments subsystem. solar

array

2.1.5.1

totaling

observa-

10

power

Power

cumulative

The wings

Subsystem

for the

comes

HST

from

major and

the

and

components their

the

electrical are

electronics,

into orbit,

the on-board power

arrays

HST

to deploy

are

and power

from

Solar

discussed

this

the

extended

and

distribution

subsystem

Arrays.

more

the

The

thoroughly

major

wing

source

later

units.

(see

Figure

array

panels,

the HST

Each array wing has assembly. This consists unit,

in this chapter, power.

cell blanket

The electricity

charges

electronics

solar

of electrical

has a solar

energy.

cells

the

drive

to assimilate by the

batteries.

an electronics control of a solar array drive

which

motors

Each

produced

transmits

commands to the wing assembly, ment control electronics unit, extending

positioning and a deploywhich controls

and

retracting

the

wings. 2.1.5.2

Batteries

trollers.

The

and

Charge

six nickel-hydrogen

Current

Con-

batteries

pro-

vide backup power when the HST is within the earth shadow and the solar arrays are eclipsed. When

fully powered,

a maximum power

Electrical

Electrical

a faint-object

time

enough solar

control

power

can un-

reaction wheels to adjust the prethe guidance sensors point the

to within

their

the sun's

Working

is placed

later

The array electronics, the SSM, the OTA, the SI C&DH, and all scientific instruments receive

array

track-

fine

and

the

the power

maneu-

the star

within

duties.

section.

Telescope

Shuttle, provide

updates

sky. Once

two

in the

begin converting solar radiation into electricity. This is stored in the batteries and distributed by

solar

stars,

located

as

speed.

guide

are

the equipment

Then

are

torquers

area,

arrays

2-17).

reaction

spacecraft

the target

in that

attitude

magnetic

preselected

out brightly

the

or decelerating

and

reaction-wheel

ers locate

point

can begin repo-

short-term

pointing

vers.

ac-

the HST toward a new target. sense the HST's vehicular

and provide

to assist

the

and torquers, sensors. The

commands

accelerating

required to rotate The rate gyros

the

a reference

Telescope

solar

the Space

Space

batteries,

100 lb (45 kg).

2.1.4.4

the

located

of the

3 in. (8 cm)

All

each

battery

of 68 amp-hours.

to supply

can produce

This

is enough

the HST

and

its major

3.5 hours

after

switching

for greater

than

tery power

before

as a power

source.

the solar

arrays

systems

must

to batbe used

scientific power

The solar

the two

processed

six bat-

one

teries, six charge current controllers, one power control unit, and four power distribution units.

2-14

arrays

recharge

through

per battery.

the batteries.

a charge Each

charge

current current

also provides

a voltage-temperature

the

battery.

charging

Power

is

controller, controller control

for

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CMDS

PWR CTRL UNIT

CMDS

P

SSM SA Sis OTA

PWR=i

1

SI

TLM --D,,-ORBITER PWR (PRE-DEPLOYM ENT)

Figure The

batteries

teries

and

minum

are

casing.

doors

520 lb (236

consist The

batteries

of three

2.1.5.3

Power

Units.

The

and

switches

solar

arrays,

trollers.

The

main

power

units.

The

section

(see

Figure

Control

power

control

batteries, power

an alu-

are attached

to the

bays

2 and

unit

interconnects between

and charge

current

control

3, in

Distribution

unit provides

line to the four power power

unit

the conthe

distribution weighs

about

120 lb (55 kg), measures

43 x 12 x 8 in. (109 x 30

x 20 cm), and is located ment section.

in bay 4 of the equip-

The

four

the inside er lines,

power

distribution

of the door switches,

units,

to bay 4, contain

fuses,

Subsystem

2-18).

flowing

control

Power

bat-

inside

and

electricity

Electrical

kg) for three

of 23 cell plates

of equipment

groups

2-17

and monitoring

located

L

on

the powdevices

2-15

Figure

2-18

Nickel-Hydrogen

Battery

C&DH

leading

to the

dedicated and

rest

SI C&DH;

bution 12.5

OTA,

x 45 cm) and Thermal

overall

Each

25 lb (11

plan

controls, covering

15 layers

electric The insulation

of aluminized

ing exteriors. the

cold

passive

tape

with

These

of space

and

builds

reflect

include

paints

protect

and

solar



Radiation and MI,I

venting



Over

200

where

or

to monitor heater

2-19

temperatures nents

within

mounted

and structures The

each

limits

interfacing

even

ronmental earth

set

subsystem

on the SSM

subsystem

peratures

control

orbit,

equipment

will maintain

and heat

section and Sis.

component

for "worstcase" to "hot"

compo-

with the OTA

fluctuations,

shadow

maintains

for the

events

passage solar

tem-

from from

2.1.7

Sating

guard

(AL)

aperture-door

less,

Specific

patterns

of FOSR

and

the

bulkheads

to

maintain

and

pro-

indicating

the

System

a contingent,

pointing well

redundant

and

on

It

and

called

assembly.

the spacecraft

the

Telescope's

The

sating

occurred the

HST,

to cut

is

atti-

to get maximum

sun

power

by

system

can

with no communications

link to ground control for up to 72 hours. that time, it is assumed, the STOCC the

as

system

electrical

drains.

for

of

the pointing This

the Space arrays

conserve

power

exists

many

components,

hardware

the solar

to safeNonethe-

system uses

and data-management

move

includes

in orbit.

3' or sating

as dedicated

exposure,

SSM

design equipment

operations.

during

analyze

any

Within would

problem

off communications,

that

and

cor-

problem.

the

sun

MLI blankets

thermal

inter-

of thermal

any breakdown

to maintain

of

tape

facing

location

Telescope

tude,

on the exteriors of the equipment section bay doors, with internal MLI blankets on the between

and

emergency

rect FOSR

and

used.

designed

for the light shield

surface

the

Space

against

recontact

Aluminum

placed

components

(Contingency)

Hubble

operate

MLI thermal blankets forward shell

sensors externally

individual

"cold"

equipment

features

scientific

on the SSM, with symbols of protection

minimizing

thermal-protection

the

operations

electronics

operation.

Specific include:

protect

SSM,

safemode

like envi-

exposure

generated

to

shows

type

The

thermal

on the aft shroud

temperature

control

sec-

heat

up.

SSM

dissipating

inside the aft shroud doors, on the aft bulkhead and

the

overlapping The

heat-

FOSR tape exteriors

shields blankets

nally,

Figure

require-

Other

reflective

areas

placing

shroud interiors instruments

tection

against

heat.

using

as

and use of

temperature

on the side of the equipment in orbit shadow

Silverized (AG) and aft bulkhead

an

of the remain-

coverings

techniques

absorptive

most

such

throughout

Optior sil-

of equipment

match



blankets

Kapton,

covers

to

to

equipment tion most

en-

heaters,

placement

space

ments,

kg).

uses passive,

Efficient bay

distri-

outer layer of aluminized Teflon Flexible cal Solar Reflector (FOSR). Aluminized FOSR



such as multi-layer 80% of the HST exte-

temperatures.

verized

are

10 x 5 x 18 in. (25 x

supplemental

maintain have

weighs

units

instruments,

the SSM.

about

HST thermal

and

Two

Control

ergy-conserving insulation (MLI) rior,

HST.

scientific

two supply

unit measures

2.1.6

The

of the

to the

balance

bays

The sating system automatically monitors the HST on-board functions in Monitor Mode, which the STOCC can turn on and off or override.

The

indicate tioning.

2-16

system all Space If

the

sends

"keep-alive"

Telescope sating

signals

systems

system

alerts

are

that func-

ground

_--

AL FOSR

z- _PS"g °"_

_SM, /

_LHAECM_LAZE__/'_.,.|

I,,L_os_l ,_o_

l;°s;

+VI--F---=_-_

I I

....

__

BLACK--'7,_

VF°S_

_--

IJ

lli-- I

-=},___

_1

_JIII

I

))

._

I

II

//

\\

!..r_ _,j j,,,lllj,,, .._ML'_.... u1_.J'-'II _

ML, #

M_,_

] L

Figure 2-19 control

to a problem,

special

failure

the problem control.

The

Placement

the STOCC

investigation while

the

investigation

sating

team

as a data

or flight

produced

inconsistencies

will classify

expected

performance,

as a flight

The

data

how

If possible,

the

to correct STOCC

be classified investigation

Telescope from the lem. If the situation STOCC may nance mission.

the problem. will

adjust

the

an

unplanned

the

Space

the

progression

of

sating contingency

depending

upon

Telescope.

If a malfunction

threaten initially

the

system

Sun Point

arrays

point

solar

power.

the situation

HST's

will move

into

operating aboard occurs

survival,

follow

the

Software

a

modes the Space

and does sating Inertial

system

will

not

system

operating

90o ML,

complete

2-17

pointing the HST

the

power

control subsyswill enter Soft-

Mode.

the

The

telescope

sating

and

solar

constant

will remain

anticipating The STOCC

sys-

so the

the sun to generate

temperatures

above

within survival

a return to normal must intercede to

the malfunction before any science operor normal functions can be resumed. the sating

through

computer

worsen,

the system

system

under

Problems

that

of the

will be operating

software. will turn

safemode

(PSEA), any

electrical

HST equipment

temperatures, operations.

conditions

control

electronics

Hardware could

If over

assembly

Sun

provoke

to the

Point

Mode.

this action

include

following:



A computer



Batteries

Hold

Mode. The system will hold the HST in the last position commanded. If a maneuver is in

a marginal

Vehicle

toward

To this point,

mainte-

will

detects

will maneuver

pointing Meanwhile,

sating

problem, or an internal tem safety check fails,

repair ations

ground to solve the probcontinues or worsens, the

consider

___

on SSM

progress,

tem

team then will indicate the probable cause, list the subsystems and components involved, and recommend

Protection

ware

Ira flight system deviated from

failure

-M_.,

If the system

this would

this would

problem.

maintains

If spacecraft

Jh,._ M,,'_=_:_

maneuver, then hold the HST in that position. It will suspend all science operations until the malfunction is corrected.

the problem

or errors,

be classified as a data problem. such as an electrical unit

in a

to evaluate

system

problem.

of Thermal

will call

team

I""_' .;

FOSnJ

malfunction losing

more

than

50%

of

their

charge •

T¢¢o of the three



The

data

rate

management

gyro

assemblies

subsystem

failing failing

If these stop

conditions

sending

Sun Point

will

equipment components computer

the

solar coarse

arrays sun

reversed

quickly,

tion

is a

from

lengthy

the

and

com-

turn

if not

will turn

equipment

process

from

Space

Telescope

tion for over

can

72 hours

NORMAL

[

I I I I I I__

HST the

listed

above,

Gravity

the HST

the

PSEA

spacecraft

Gradient

computer

Shuttle

uses

This

by

to earth

orbit-

can retrieve

the

to maneuver

only

in Figure

enters

Mode.

in a gravitationally-stable

until the Space

brought

retrieval

mode

into a survival

magnetic

for major

repair.

2-20 for a diagram

orbit,

torquers. whether and

maintain

The

the misthe HST

See the chart

of the sating

system

any contact

2.1.7.1

PSEA

mode

electronics

and

RMGA.

The

assembly

pointing

safe-

consists

of

of

from

internal

assembly

failure.

It weighs

86

OPERATIONS

!

_cOFTWARE

HARDWARE%

Ii

GYRO

I

ONTROL



INITIATE SAFING



INITIATE

SI PAYLOAD SEQUENCE ST LOAD

SHEDDING

i •

REASONABLENESS CHECK

ORIENT

SEQUENCE SA TO +

V3 AXIS

I 1

J

STOCC COMMAND

CAUSES

LOSS OF KEEP ALIVES • BATTERY DCHG. >50%

FAIL

• TWO

• SPC LIST EXHAUSTED

GYROS

FAIL

CHECK



NO COMMANDS



MEMORY TESTS FAIL (PARITY ERROR INTERRUPT AND WRITE



FOR

PROTECT

CPU AND FAIL

100 HOURS

I

HARDWARE SUN POINT

I t

+ V3 AXIS TO THE SUN)

r SUN

CHECKS

(ENABLE/DISABLE BY STOCC)

STOCC COMMAND

GRADIENT GRAVITY

INERTIAL HOLD •

MAGNETIC

TORQUER

DUTY CYCLE CHECK EXCEEDED

SOFTWARE SUN

• WHEELSPEED EXCEEDED •

BATTERY DISCHARGE >50%

ANGLE

TO SOLAR ARRAY PERPENDICULARITY CHECK EXCEEDED

VIOLATION)

TIMING

POINT (+ V3 AXIS ORIENT SA TO + V3 AXIS

Figure

TO THE

SUN)

_]

2-20

Sating

2-18

40

electronic printed-board circuits with redundant electronics to run the HST even in the case

this condi-

FOLLOWING

• TESTS

it.

progression.

STOCC

"1 MONITOR

if more continue

this situa-

involving

without

time, cannot

STOCC again must evaluate sion should be discontinued

analysis. The

a reasonable

adjusted

begins

are

beyond

gyro assembly

the

repair

fail, or if the PSEA

The

not required

Recovery

and

systems

al attitude

by the is not

assembly

if contact

delayed

keeps

already

to face

But

Contingency

unit. A payload

and,

STOCC.

operations

off

contin-

the sun, guided If the situation

survival.

will

conserve power. could include the

the safemode

power

PSEA

if the emergency

Telescope

toward sensors.

for the HST's

HST

will begin,

Space

removing

the

the SI C&DH

sequence

done,

to

and,

ues for two hours, sating

the

system

signals.

Mode

command

selected Shut-down DF-224

the sating

the "keep-alive"

In Hardware puter

occur,

System

Progression

INITIATE SEQUENCE FOR RESCUE j

BY STS

ib

(39 kg) and is installed in equipment section bay 8. The retrieval mode gyro assembly, also in bay 8, consists of three gyroscopes that are less precise than the rate gyros. 2.2

THE OPTICAL ASSEMBLY

TELESCOPE

The Optical Telescope Assembly (OTA) was designed and built by the Perkin-Elmer Corporation. Modest in size by ground- based observatory standards, and of a straightforward optical design, the accuracy with which the telescope assembly has been built, coupled with its place above the earth's atmosphere, render its performance superior. As is common practice in the design of large telescopes, the OTA uses a "folded" design, which enables a long focal length of 189 ft (57.6 m) to be packaged into a small telescope length of 21 ft (6.4 m). (Several smaller mirrors in the scientific instruments also use this design to lengthen the light path within the particular scientific instrument.) This form of telescope is called a Cassegrain, and its compactness is an essential ingredient of an observatory designed to fit inside the Space Shuttle payload bay. Conventional in optical design, the OTA is unconventional in every other respect. Large telescopes at ground-based sites are limited in their performance by the resolution attainable by operating under the earth's atmosphere. But the Space Telescope will orbit high above the atmosphere and provide an unobstructed view of the universe. This is why the OTA was designed and built with exacting tolerances to provide near-perfect image quality over the broadest possible region of the spectrum.

The OTA is a variant of the Cassegrain, known as a Ritchey Chretien, in which both the mirrors are hyperboloidal 1 in shape. This form is completely corrected for coma 2 and spherical aberrations to provide what is known as an aplanatic 3 system. The only residual aberrations are field curvature and astigmatism. Both of these are zero exactly in the center of the field and increase toward the edge of the field. These aberrations are easily corrected within the instrument optics. For example, in the Faint Object Camera there is a small telescope designed to remove the image astigmatism. Figure 2-21 shows the path of a light ray from a distant star as it travels through the telescope to the focus. Light travels down the tube, past baffles which attenuate reflected light from unwanted bright sources, to the 94.5-in. (2.4 m) primary mirror. Reflecting off the front surface of the concave mirror, the light bounces back up the tube to the 12-in. (0.3 m) diameter convex secondary mirror. The light is now reflected and converged through the 23.5-in. (60 cm) hole in the primary mirror, to the telescope focus, 3.3 ft (1.5 m) behind the primary mirror. The focal plane is shared between five scientific instruments and three fine guidance sensors by a system of mirrors. In the very center of the field of view is a small "folding" mirror which directs light into the Wide Field/Planetary Camera. The remaining "science" field is divided between four axial scientific instruments, each receiving a quadrant of the circular field of view. Around the outside portion of the "science" field, the "guidance" field is divided among the three fine guidance sensors by their own "folding" mirrors. Each FGS receives 60 square arcmin of field in a 90-degree sector. See

1 "Hyperboloidal" refers mathematically to the shape of the mirror. A hyperboloidal slightly deeper curvature than a parabolic mirror. 2 "Coma"

are aberrations in the image that give it a "tail".

3 Corrected everywhere

in the field of view.

2-19

mirror has a

Figure view.

The

2-22

for the

fields

Optical

Telescope

Assembly

instruments

in that

is a "host"

and fine guidance

it maintains

the

structural

ponents

of

assembly,

the

OTA

the

plane

secondary

and

the

the mirror

Systems

The

assembly

by

Perkin-Elmer;

section

(see



The



Main

• •

Reaction plate and actuators Main and central baffles

mirror the

the

OTA

systems

are

LMSC

Figure

2-23).

These

primary

assembly

also

parts

2.2.1.1 blank

Primary

Mirror

Assembly

mirror

mirror which

itself is the

scope,

and

assembly

supported structural the

main

provides

rest of the spacecraft, attachment

assembly

chosen

cient,

brackets

up of the

inside the main backbone of the and

central

through linking

baffles. coupling

ring, teleThis

of Corning its very

assures

to temperature facesheets

of glass

are

mirror

The

ring to the

SECONDARY

mirror

ground

coeffi-

The

in which

mirror

two light-

by a core,

or

ribs in a rectangular

weighing

blank,

to shape

MIRROR

8000

results of a sol-

lb.

8 ft. (2.4 m) in diameter, by Perkin-Elmer

/

2-20

Path, Main

Telescope

was

in P-E's

(3) --3 AXIAL

SCIENTIFIC

I

L_

Light

(P-E),

INSTRUMENT

MIRROR

MODULE

2-21

It

minimum

This construction mirror instead

[

Figure

that

glass.

expansion

telescope

separated

PRIMARY

DOOR

Works

changes.

honeycomb

mirror

(ULE)

construction

FINE GUIDANCE SENSOR

APERTURE

primary Glass

low

the

grid (see Figure 2-25). in an 1800-1b (818-kg) id-glass

The

2-24.

to the

a set of kinematic the main

Mirror.

for

which

filling,

in Figure

as ultra-low-expansion

is a "sandwich"

is made

the structural

pictured

is a product

weight primary

are

Primary

is known was

mirror

ring structure

sensitivity 2.2.1 The

Module.

to

these com-

assembly, and

All

built

equipment

for The

primary

assembly,

section.

designed

are

structure

equipment built

Support

sen-

support

and optical-image stability required instruments to fulfill their functions.

focal

of

provides support to the primary mirror and the OTA baffles. It has the following major parts:

the scientific sors

instrument/sensor

(4)

I

(IMAGE RADIAL SCIENTIFIC INSTRUMENT

FORMED

HERE)

+ V3

HIGH

AXIS

GUIDANCE

SENSORS

(3)

RESOLUTION FGS #2

SPECTROGRAPH

"_

SPEED PHOTOMETER OPTICAL

CONTROL

SENSORS

(3)

+V2 AXIS

CAMERA

FAINT

OBJECT

SPECTROGRAPH 2 DETECTORS, SEPARATE APERTURES WIDE

FIELD/PLANETARY INCOMING

(VIEW

Figure large

optics

fabrication

close

to its final

transferred ishing its final

Here

surface

facility.

hyperboloidal

to P-E's

facility.

2-22

Fields

quality.

The

AXIS

INTO

of View,

FORWARD PAGE)

InstrumentsSensors

Once

it was

tance

shape,

it was

known of the

computer-controlled the mirror

IMAGE

LOOKING

+V1

CAMERA

pol-

was polished largest

to

deviation

at the

Figure

the

The primary

States, would

mirror

was

the

size

of the

United

the highest mountain or deepest valley deviate less than two inches from the

surface.

being

ground

num ride,

and only

a protective 0.1

and polished,

with a reflective and

layer 0.025

respectively. The fluoride minum from oxidation

the glass layer

sur-

back

85%

mirror

right

mirror

through

the

and

also

by three

of the

glass

for lateral

spec-

visible

light.

mirror.

is mounted

to the

line

ultraviolet for

the primary

a set of kinematic

penetrate

face was coated

in the

over

shows

attach

straint, After

2-26

through ages

and

emission

The reflective quality than 70% at 1216 ang-

(Lyman-Alpha), range,

from perfection anywhere on the surface of the mirror is less than half a millionth of an inch. If primary

hydrogen

as Lyman-Alpha. mirror is better

stroms tral

important

to the main ring

linkages.

The

link-

by three

rods

that

glass, pads

for axial bonded

conto the

support.

of alumi-

of magnesium

fluo-

micrometers

thick,

layer protects and enhances

the alureflec-

2-21

2.2.1.2

Main

Ring.

The

main

ring

structure

encircles the primary mirror, the main baffle

mirror; supports and central baffle,

the

integrates

metering

truss;

and

the and

the elements

--

SECONDARY MIRROR ASSEMBLY GRAPHITE METERING

EPOXY TRUSS

BAFFLE

SUPPORT

SYSTEMS

MODULE

SENSOR

(3)

PLANE STRUCTURE

ALUMINUM MAIN BAFFLE

SCIENTIFIC INSTRUMENT

ELECTRONIC

BOXES

PRIMARY

MIRROR

MAIN

RING

ED

HEAD

STARTRACKER

RADIAL

Figure of the telescope made of titanium, an

outside

Figure

2-27).

a kinematic

2-23

OTA

to the spacecraft. The ring, is a hollow box beam 15 in.

weighs

1200 Ib (545.5

diameter

of

It is suspended

9.8

ft

kg), and has (2.9

inside

m)

(see

the SSM by

support.

head

Reaction is a wheel

ter.

behind

It radiates

supports

the main

ring,

reaction forming

spanning

plate a bulk-

its diame-

2-22

out

the central

is to carry

an array

warmth

to the back

taining

its temperature

beryllium Plate. The of I-beams

(1)

Components

also 2.2.1.3 structure

(3)

SCIENTIFIC

INSTRUMENT

(38 cm) thick,

(4)

tors

from baffle.

attached

ring,

Its primary

of heaters, of the primary

radiate

mirror,

and stiffness,

the

primary

main-

Made

of

the plate

a set of 24 figure-control to

which

function

which

at 70 degrees.

of light weight

supports

a central

mirror

actuaand

arranged around the reaction plate in two concentric circles. These can be commanded from

the ground, if necessary,to make small corrections to the shapeof the mirror. 2.2.1.4

Baffles.

vent

stray

sun,

moon,

light

The from

and

baffles bright

earth,

of the objects,

from

OTA such

reflecting

MIRROR CONSTRUCTION

pre-

FRONT FACESHEET

as the

down

the

telescope tube to the focal plane. The primary mirror assembles includes two of the three OTA baffles. INNER EDGEBAND

Attached outer,

to the front main

baffle

is an aluminum

(2.7 m) in diameter equipped stray

face of the main

and

light.

The central

in shape,

and

the

cylinder,

9 ft

15.7 ft (4.8 m) long.

with fins internally

conical

ring,

to help

baffle

,LIGHTWEIGHT CORE

It is

attenuate

is 10 ft (3 m) long,

attached

to the

,OUTER EDGEBAND

reaction

plate through a hole in the center of the primary mirror. It extends down the centerline of the telescope

tube.

painted with reflection. 2.2.2 The

The

flat black

Secondary secondary

the front

face

secondary

baffle paint

Mirror mirror

interiors

were

to minimize

light

Assembly

assembly

cantilevers

of the main ring and

mirror

REAR

at exactly

supports

the correct

I

off (THE

the

MIRROR

MIRROR

,,_,_,_-

MAIN

_-PRIMARY

_'ACTUATOR

_

7971

GLASS)

T _//_/_[O_YY

The

(see

secondary

mirror. within

of an inch

This position a tenth of

whenever

The

assembly

subassembly,

a light

graphite-epoxy

structure

/

CODE

Primary Mirror Construction

is operating.

of the mirror outer

J

2-25

one-thousandth

MIRROR

scope

BAFFLE

CONNING

in front of the primary must be accurate

BAFFLE

_zdl//l/I/lll/i./l/I/I/l_

CENTRAL

OF

EXPANSION--SILICA

ASSEMBLY

"_

k

MADE

position Figure

PRIMARY

IS

ULE--ULTRA-LOW

mirror

truss

and an support

2-28).

subassembly

contains

the

_..,,_

mirror,

which

is mounted

on

three

alignment actuators controlling and orientation of the mirror. All Figure

tele-

is composed baffle,

metering

Figure

the

2-24

The Primary Assembly

Mirror

within

the central

truss support.

2-23

hub

the are

at the forward

pairs

of

position enclosed end of the

BASE

PLATE

- ACTUATOR

PAIR

SECONDARY

MIRROR

)NDARY MIRROR BAFFLE

/ I ACTUATOR PAIR

CLAI FLEXURE

Figure The

2-26

secondary

10.4X,

mirror

converting

ing rays prime

from

focus

the center through

Pn'mary

f/02.35

to a focal

of the primary central itself

coated

is a convex

with

is even

ratio where

to the

aluminum

right position The

greater

than

picked

point.

sensors

its

The

mand

can be adjusted

to align

the

secondary

principal

ondary

T CENTRAL

INTERCOSTAL RIB (48)

\ N

BAFFLE

/-\

J

mirror

__¢__

--

rings

and a central

com-

BRACKETS

(5)

RAO_LI-B_M (_s) _ROL

ACTUATOR

FLEXURE

_i_..._._/_:_

_

_"_-_

--_

ft

mirror. (2.7

chosen

m)

for

to nearly ary mirror

zero. must

attached

tiny

stiffness,

stay perfectly accurate when

truss,

a

for the seca

and

graphite

Graphite

light

was

weight,

and

expansiveness

This is vital because

mirror,

sec-

to three

is

structure.

the structure's

(2.5 micrometers)

the

16 ft (4.8 m) long

diameter,

its high

the primary

(24)

in

of

structure

truss,

epoxy

it reduces

the second-

placed

relative

to

to within

0.0001

in.

the telescope

operates.

at one end to the front

face

of the main ring of the primary mirror assembly. The other end has a central hub which houses

--

the secondary

_

tion (MLI) 2-27

data

sensors.

is the metering struts

support

The

fiber-reinforced

cal axis. Figure

system's

guidance element

48 latticed

The truss is attached AXIAL

control

fine

assembly

primary

in just the

FIGURE

quality.

from

structural

with

because CENTRAL raNG--N

image

calculated

optical

in the

cage

by ground mirror

by the

Assembly

perfect

are

located

ondary

actuators

to provide

surface

9 The

up

Mirror

12 in.

magnesium the

Secondary

adjustments

it passes

from Zerodur and

2-28

system

focal

and

convex

Figure

toward

hyperboloid,

and is made

of

converg-

it back

mirror,

baffle

It is steeply

accuracy mirror.

a magnification

the primary-mirror

(0.3 m) in diameter, fluoride.

Mirror

of f/24 and sending

the

The mirror glass

has

J

The Main Ring and Reaction Plate

temperature Farenheit

2-24

mirror

Aluminized material

and mylar

baffle

along

the opti-

multi-layer

insula-

in the truss compensates

for

variations of up to 30 degrees when the HST is in earth shadow so

the

primary

aligned.

See

support The

and

secondary

Figure

2-29

mirrors

for detail

from

remain

on the truss

baffle

secondary

extends

reduces sources

mirror

almost

subassembly

to the primary

the stray bright-object outside the HST field

2.2.3

Focal

trackers

2-30).

structure.

conical

star

the sun in space,

Plane

Structure

light

mirror.

light from of view.

and

plane

structure

(FPS)

rate

replacement mal isolation

the

sensing

It also provides

units

bright

The

structure

(3.04

m) long

is 7 ft (2.1

m)

and

over

weighs

square

is a large optical

extreme

locations,

thermal

because

stability

and

and

strong.

The

FPS

supports

for

orbital

guidance

units

The

-V3 side

of the

structure,

10 ft (545.5

the Sis away

used

during

The focal

plane

face of the points ment

structure adjust

the

has

light-

metallic

replaceable

cantilevers

attached to

The structure

for

stiff,

have

maintenance.

main ring,

that

distortions.

it must be

and

FGSs.

by

1200-1b

mounts

and

ther-

kg). It is made from graphite-epoxy, augmented with mechanical fasteners and metallic joints at

Assembly

supports

Figure

for in-orbit

It

weight,

and physically

(see

the facilities

bench which aligns the image focal plane of the HST with the scientific instruments and fine sensors

fixed-head

of any of the instruments and between each instrument.

strength-critical The focal

supports

fine

and latches location so

exchange

scientific

equipment

easily

flexible

eliminate provides

guidance

guide-rails mounting

off the aft

at eight

thermal a fixed align-

sensors.

at each Orbiter

It

has

instrument crews can

instruments

and

other

in orbit.

PRIMARY MrRROR RING

MAIN

-\'_

--

,



"_'_"'_

/ffA

FOCAL

PLANE

STRUCTURE

/Sl

N_

CONNECTOR

" __EM

/

_',_,,/_

HANDLES--" FIXED-HEAD STAR

TRACKER

,,..-"r"

1 _- SI (3)

LATCHING MECHANISM

Figure

2-29

Mirror Metering Structure

Truss

Figure

2-25

2-30

Focal

Plane

Structure

V2

2.2.40TA

Equipment

Section

bilization.

There

sembly The

equipment

scope

section

Assembly

is a large

compartments on

the

mounted

forward

2-31).

control

guidance

electronics,

ics, optical section

storage,

unit.

bays;

(see

Figure the

are

fourth

doors for easy access, for the electronics, and for thermal control.

electrical

power/thermal

control

cabling heaters

electron-

distributes

power

from

the

SSM

electric

power

subsystem

to the

OTA

sys-

tems.

The

controllers

temperatures. from also

system

to regulate

This

prevents

cold space temperatures. collects thermal sensor

mission

the

mirror

unit

electronics and

telemetry

interface

its response

to the unit.

to the

commands electronics

go through

com-

from

the

the

data

The

optical

control

trols

the

white

light

electronics

optical

control

(OCE) sensors.

interferometers

quality

ground

which

of the OTA

for analysis.

each FGS, OCE.

but

unit con-

and are

are the

send

There

all OCSs

These measure the data

is one

OCS

controlled

to for

by the

uses mirror

The data interface

distortion

The EP/TCE data for trans-

units

interface between

and

the

unit (DIU) is an electronic the other OTA electronics

HST

command

and

telemetry

system.

to the ground.

three

fine guidance

provides

power,

each

guidance

fine

performs faces

monitors

Positioning

2.3 The

control

and

mand.

the

system

thermostat

(ACE)

sensor.

have

ics (EP/TCE)

temperature-control

as-

to the 24 actuators attached to the primary mirror and six actuators attached to the secondary mirror. The ACE selects which actuator to

optical The

guidance

the command

ground interface

for equip-

All bays

actuator

move,

equipment

used

support.

fine

electronthe

OTA

The

provides

power/

and

The

of

spacecraft

control

seven

for

set

system,

for each

electronics

Tele-

electrical

electronics,

two

outward-opening and connectors and insulation

OTA actuator

interface

has nine

ment

the

SSM

electronics

control

data

Optical

semicircular

of the

the

thermal

the

outside

shell

It contains

DMS

for

is a guidance

electronics

commands, sensor.

computations telescope

The

electronics

pointing

line-of-sight

pointing

to unit

and inter-

system

for efand sta-

The

LOOK,,G_ORWARD

cumference

Figure

__

2-31

guidance

of

between

Figure

long,

3.3

the

2-30). ft (1

sensors

intervals

enclosure

and

sensor

wide,

kg). Perkin-Elmer FGS

plane

frame

Each m)

the

are

the

cir-

structure, main

ring

is 5.4 ft (1.5 m)

and

made --

(FGSs)

around

focal

the structure

(see

used

_/__//

-7

SENSORS

weighs

485

lb

called

a

the sensors.

sometimes

radial -- actually guidanceare sensor sensors bay and aremodule a elements wavefront of sensor. the houses OCS, The awhich wavefront

-w

ON

fine

at 90-degree

Each

V ---_-v2

{3OORS

three

located

(220

MLI

GUIDANCE

units

telemetry

for the sensor

with the spacecraft

fective

(FGE)

and

FINE

to align

and

optimize

the optical

system

of

the telescope. _

]

i

_

;

\

,_'_--"'-

The ability of the HST to remain pointing distant target to within 0.007 arcsec for

FG;_{_mm_mm_GE

The

OTA

Equipment

Section

periods

2-26

of time

is due

largely

to the accuracy

at a long of

the

FGSs.

The

and measure

guidance

sensors

any apparent

cy of 0.0028

arcsec.

lock

motion

That

on a star

to an accura-

is equivalent

from New York City the light on an aircraft flying

direction the

galactic

two sensors

motion of a landing over San Francisco.

lock on a target,

the third can

the star.

in Chapter

3.

FGS

The

fine

Composition

can be anywhere

guidance

structure

housing

servos

the image,

beam

tubes.

The

adjustment alignment

has

a large

for

and

field of view point

the

lenses,

to fine-track

splitters,

and four

photomulti-

with

track

of mirrors, prisms

entire

(60

of a large

the image,

required

cise

consist

a collection

to locate

plier

sensors

to move

the

a target

star.

armin

2) field

stars, used

mechanism

and

makes

the

HST into preEach

of view

sensor

to search

a 5.0 arcsec-squared

by the detector

prisms

to pin-

in pairs

to aim

star.

The

FGS

within

fine

guidance

the Space System,

work

The

Guide

Telescope. developed

alogs

and

tion

target

First

one

charts sensor

ignated

guide

stars

and

star.

The

located,

each

to find

will search

Selection

Institute,

near

it easier

the first sensor sensor locates

guide

Star

by the Science

to make

star. After the second target

sensors

cat-

observathe

target.

for a target

guide

locks on a guide star, and locks on another

guidance keep

observation target in the lected scientific instrument.

stars, the

once

image

aperture

of

of the the

"science"

of view has the ture distortions. view was finding

chosen

field.

se-

This region

secthe

of the field

greatest astigmatic and curvaThe size of the FGS field of to heighten

an appropriate

guide

can

move FOV

tectors

ters

the probability star,

even

of in the

2-27

within

to keep

position

the

the star

its line using

field

signals

of

so the to find

FGS

has to

to the HST image

of sight

a pair

60

star

this field,

the star, error

has

guide

in that

per-

anywhere

of star

selector

of as an optical in a North-South

other moves FOV (5 arcsec

to any

Encoders the exact

FOV

The

Each may be thought -- one servo moves

East-West. They 2) of the FGS de-

in the

whole

FGS

within each servo system coordinates of the detector

field.

send back field cen-

at any point. there

is often

some

uncertainty

about

the

exact location of the guide star in question, the star selector servos can also cause the detector to execute a search most probable guide a spiral

pattern,

of the region around the star position. It searches in

starting

at the center

ing out until the detector seeks.

Then

"finds"

the detectors

into "fine-track"

mode

about

the

The

position

and

detectors

ometers

of the

control

hold

themselves

called

to go

the star

image

to the spacecraft

are a pair

Koesters' tubes.

wavefront

the interferometers edge

star it

of view, while the send information

star

prisms, Each

in one axis, so two are needed.

one

the guide

system.

photomultiplier incoming

and spiral-

are commanded

exactly centered in the field star selector servo encoders pointing

Each fine guidance sensor uses a 90-degree tor of the telescope's field of view outside central

des-

to move

direction; the steer the small

Since The

found

it and send

its large

servos. gimbal

FGS

anywhere

Having onto

telling how fectly still.

and Function

Each available.

will "look"

"lock" FGS

of view.

arcminutes

the

2.3.1

-- near

poles.

field

square interest

is discussed

population

An FGS "pick-off" mirror intercepts the incoming stellar image and projects it into the sensor's

measure the angular position of a star, a process called astrometry. The astrometric function of sensors

star

to seeing

large When

of the lowest

of the

from telescope

detector

on the

guide

the wave entrance

to

operates

Operating

the distant

compare

of interfercoupled

star,

phase aperture

at

with

the phase

phases

are

at the opposite

equal,

Any phase which must

the

star

edge.

When

is exactly

difference shows be corrected.

the

the

centered.

a pointing

FGS

shown

turn,

or "fold,"

thing

inside

the

The

the

the telescope's All optical

FGS

in order

enclosure,

wavefront

astigmatism

elements

are

ature-controlled

and

bench.

Figure

2-32

Figure

2-32b

OTA.

ror, ror.

field curvature.

mounted

diagrams

on a temper-

used

composite

cutaway the

pickoff

are, like the These,

The

mirror

FGS

to compute

detec-

however,

imperfections

the alignment

contain

are

in the through informa-

of the secondary

and the optical quality The data is telemetered

system. actuator re-orient is a simplified

sensors

interferometers.

tion about

to correct

graphite/epoxy

optical

the

to fit everyand

to the

designed to measure small imperfections stellar wavefront result from its transit

from telescope to detecoptical elements which

beam

close 2-32a.

error

tors, Along the optical path tor, there are additional

enclosure

in Figure

mir-

of the primary to the ground

any corrections

to the

mirand

optical

These corrections are converted into commands and sent up to the HST to the OTA.

of the FGS;

optical

path. The wavefront sensors are very precise optical instruments and are mounted to a machined

2.3.2

Wavefront

Sensor

be-ryllium optical ture-controlled, to

The optical control system is a system of three wavefront sensors and control actuators which

the

FGS

the

wavefront

enable

once

the

ground

alignment

controllers of the

to correct

telescope.

and adjust

They

which

that is temperastability. Unlike

will be used

sensors

the OTA

month

fit inside

sensors,

bench maintain

will be used

has been

aligned

constantly, infrequently

during

the first

in space.

ENCLOSURE r--

ASPHERIt MIRROR

COLLIMATING

FGS

ST

"-"

/

F

COLLIMATOR _FIRST STAR SELECTOR

./

PINHOLE/LENS ASSEMBLY (4)-

/

OTA_

/

/

/

// I'

/

REFRACTIVE GROUP F SECOND STAR

/SELECTOR

-_

LI

LI /

- STAR SELECTOR

- J'I

i M"F'O'S

DOUBLET LE N S (4)

r /

I\11 _ CORRECTOR

I

FIELD LENS AND

f"

KOESTE_

"--

DEVIATION PRISM

OPTICAL

v _k

DOUBLET_ _ FIELD STOP "-'__"_'_)w_.,¢_

PHOTOTUBE _.

II .,_

PRISMS

, ,

DES_._...M ERS IS _

WPUPIL

_)1_ ROTATED 90 °

I

L

BENCH

FILTERS(5), PICKOFF

MIRROR

Figure

-J

2-32a

FGS

Figure

Cutaway

2-28

2-32b

Optical

Path,

FGS

2.4

SOLAR

ARRAYS

The two solar Space

arrays,

Agency

designed

and

built

by the European

by British

serve as the main source Hubble Space Telescope. operate

the

arrays,

maneuvering

the

of power for The STOCC

extending

the

spacecraft

sunlight on the arrays. to energy and stored

Aerospace, the will

panels

to focus

SOLAR

and

maximum

PRIMARY

/

arrays solar

two-stem sette

are two rectangular cell blankets fixed

frame.

in the

CASSETTE/

The blanket

middle

of the

The

wings

are

on

arms

wings between

unfurls

wing.

at each end of the wing stretches and maintains tension.

that

of a

from

a cas-

A spreader

bar

length

of the

(4.8 m) (see

Each

wing wing,

small

that

attached

connect

mesh

tightly

panels,

roll

out made

wiring

layer

500

weighs

ten

are

arm,

to a drive

up

of Kapton.

is 15.7 ft

m) long

on each

the

kg)

are and,

and

cells with

is covered

blankets

by

are

less

so they

can roll

stowed.

Each

BAR

Solar

Array

2-33

The

primary

solar

array

deployment

is

wing.

Each

mast when

and supports erect.

mary and secondary the drive mechanism,

the side

mechanism

An astronaut

of the

raises

the

SSM

to a

to the teleone for each

has motors to hold

can raise

if the drive on

the

the

to raise mast

power

the array

fails.

Using

deployment

hand-cranks latches.

mast

the

in place

mast

manually,

a wrench

drive,

the

Once

the

solar

deployment

Subsystems

are

Wing Detail

mechanism

from

MECHANFSM

the

after

fitting

astronaut

releasing

the

wing

at full extension,

arrays

BAR

up

8.2 ft (2.5 m) wide.

for the solar

Solar Array

mast

Each

array

is raised,

mechanism

unfurls

wing

the pri-

the cassette

cushion

to protect

deployment mechanisms, and the electronic control

assembly.

ket, stretch, wing pletely

2-29

drum

the blanket,

applies

tension

and

transfers

or part

The

data

and

blanket

blan-

mechanism and

as-

panels,

motors

a

and

rolls out the blan-

evenly

way. The

secondary wing

to hold solar

The assembly

assembly.

the the

has a secondary

sembly:

subassemblies. The subsystems

SPREADER

standing position perpendicular scope. There are two mechanisms,

kets. 2.4.2

PULLEY

CASSETTE STEM

of The

solar

surface,

that

The

half

cassette.

of 2,438

thick

wings

17 lb (7.7

40 ft (12.1

five

underneath

the

drive

fiber/Kapton

micrometers

when

and

from

SPREADER

Figure

2-33).

to a glass

another than

has

panels

silver

cassette, Figure

BISTEM

out the blanket

assembly on the SSM forward shell at one end and to the cassette on the other end. The total

the

//,/_

Configuration

The solar retractable

DRIVE

The sunlight is converted in batteries until needed.

DEPLOYMENT

2.4.1

ARRAY

so

the

power can

secondary

blankets along

roll

out

the com-

deployment

mechanismalso has a manual override (see Figure 2-34).

The

electronic

monitors

control

all solar

assembly

array

system

controls

and

functions.

It con-

trols the primary and secondary deployment mechanisms and the solar array drive. FITTING

FOR

MANUAL

2.4.3

DEPLOYMENT

WING

MAST

SECONDARY

Figure

2-34

DRIVE

Fitting for Solar Array Manual Deployment

Operation

When

the

Hubble

cargo

bay

of the

stowed

against

against

the

In this

26 in.

(65

Figure

2-35). the

into

orbital

unfurls The solar array drive rotates the deployed toward the sun, turning in either direction. drive Each

array The

and

a brake

to keep

the

array

the

in a

possible

position

drive

has a clamp

mechanism ber

if opened.

to jettison

necessary

arrays

the by

light just (see

Telescope extends

ground

and

command.

and

solar

latched and

extend

Space

power

are

surface

STOCC

unfurled

absorbing

electrical

shell

SSM

facing

energy

the

and pass-

subsystem.

INSTRUMENT AND DATA HANDLING

This allows solar

Scientific

Instruments

Control

Handling unit (SI C&DH) ic instruments. It:

ring that acts as a release

the entire

by the

are

arrays

for maintenance. The

Each

the

arrays

SCIENTIFIC CONTROL UNIT

2.5

fixed position if the HST moves around in orbit. The drive can move and lock the solar array into any

solar panels

ing it to the

the the

places

position,

sun, they begin

is at the base of each solar-array mast. drive has a motor that rotates the mast on

command,

Orbiter

the

When

forward

position from

is in the

solar

with the masts

of the

cm)

Telescope the

the SSM

sides

shield.

Once

Space Orbiter,

controls

and

Data

the scientif-

a crew mem-

array



if deemed

Watches keep

STOCC.

all scientific

them

instrument

synchronized

and

systems

working

GRAPPLE FIXTURE RECE PTACLE --7 /

/-" SDM STOWAGE /HANDLE

/ =_' ./--

/

/' .-. ...... I_tlr

....

_--_--':'-

DIODE BOX SDM MANUAL

,,rr

\

A

I

-

Figure

--_

::

2-35

:

Solar Array

....

_-'-I

Wing

2-30

_'_;_1

Stowed

....

Against

[-----,t----Lc.l,_ir....l_

SSM

26.05 In. MAX.

to

Works with process,

the

data

management

unit

and

communicate

all

format,

to EVA

sci-

'-'HANDLE

ence and instruments

engineering

data

created

by the

Al18_ Al16_,,\

AlO, 2 CPMS

It was built

by Fairchild

Corp.

IBM.

and

2.5.1

SI C&DH

Camera

ponents tray

is a collection

and Instrument

of electronic

com-

replaceable

unit

to an orbital

mounted

on the door

equipment

section.

of bay

Small

ments.

The

make

C&DH

are the NASA model

face

I (NSSC-I);

(STINT)

puter;

two control

two

memory, lines

data

and

SI C&DH

so the system

failure.

See

C&DH

components.

Figure

the

formatter unit

unit

(PCU);

(RIU);

and

various

communications

by bus

coupler

units

are

dupli-

components

can recover

from

2-36 for the

layout

NASA

Figure

any single

spacecraft cessing

computer

model

unit module each holding

embedded

software

and operation for individual of

the

of the SI

programs ment data.

monitor

and analyze

standard

a central

and eight

8,192

18-bit

program

(the

It moves

data,

programs scientific

processing

I has

(CPM)

modules,

runs the computer.

The NASA

pro-

memory

words.

One

"executive") commands,

(called "applications") instruments in and out unit.

and control

The

application

a specific

and manipulate

2-36

SI C&DH

TRAY

Components

The memory stores operational execution when the HST is not

commands in contact

the ground system. Each memory five areas reserved for commands unique

to each

scientific

The computer

instru-

the collected

for

around

failed

2.5.1.2

for with

unit also has and programs

instrument.

is the

the computer formatter.

science

requests

from

or

for

the

working

equipment. Unit.

The

standard

communications

SI C&DH

data formatter.

between

unit/science

Unit/Science

of the

interface

bridge

and the control

Control

heart

be reprogrammed

future

STINT

board

Data is the

It formats

data

Formatter.

control

unit/

and sends

to

the right source all commands and data passing between the ground command, the data management unit, the NSSC-I computer, the SSM, and the scientific instruments. The unit has one microprocessor matting The data and ples

2-31

can

ground

2.5.1.3

Computer.

UNIT

BCU--'

The 2.5.1.1

REPLACEABLE

_

com-

processor

command

The

SI

com-

control

units

connected

the

INTer-

for data

central

a power

interface

(buses),

(BCU). cated

two

(CPMs);

remote

units

unit/science

units;

up

spacecraft

two STandard

circuit-board

(CU/SCF) modules

that standard

,-_. _

mod-

system, are conscientific instru-

components

JT._

A240

10 in the

remote

ules, also part of the SI C&DH nected to each of the individual

puter,

._

Components

attached

and

SSM

/

A221

_;I

The SI C&DH

J

each

for the

control

and for-

functions.

control

unit

requests, system

science

signals

of system

receives and

signals

ground and

engineering

information. are

commands,

"time

data,

Two examtags",

clock

signals

that

synchronize

the

and "processor interface munications codes.

The

unit

transmits

after

formatting

entire

tables"

(PITs),

commands

them

isolates

spacecraft, or com-

and

so the specific

requests

destination

mands

use

lates mat.

16-bit

signal words

words.

The

should

fail. The

orbital

replaceable

2.5.2

Operation

The SI C&DH

unit can read the signal. For example, ground commands and SSM commands are transmitted with different electronic commands use 27-bit

tem

command 2.5.2.1

formatter

tells

trans-

each command signal into a common forThe control unit also reformats and sends Analysis

of this

handles

System systems

trol

Power

Control

unit distributes

The

and switches

the components

of the SI C&DH

lates

as required

the

power

computer ously

memory

need

power

conamong

unit. It modu-

by each

boards,

+ 5 volts (V),

power

unit.

for example, -5 V, and

The

2.5.1.5 ule

Module

units transmit

Units.

commands,

Remote clock

mod-

and other

modules

do not send

science

Command the flow

C&DH.

Commands

data.

the drawing) face (ground unit (SSM

There

storage.

Each

2.5.1.6

and power units in contains a remote

Communications

expander Buses.

units. The

SI

C&DH contains data bus lines that pass signals and data between the SI C&DH and the Sis. Each

bus is multiplexed:

messages, requests transmits

commands, to the

and

module

requested

one

line sends

all monitoring

inter-

to every

40

devices

it to the NSSC-I

The

computers

pro-

Any failure

indi-

tests could provoke a (see section 2.1.7,

system

engineering

data

units,

and a reply

information

and

Processing. of commands enter

data

the

Figure 2-37 within the SI SI C&DH

formatter

(bottom

conright in

through the command data intercommands) or the data interface commands).

The

line

"Time-tagged"

the computer's

one dedicated the SI C&DH.

unit and up to two

scans

information.

2.5.2.2 illustrates

also

interface

msec

above).

are six remote modules in the Space Telescope: five attached to the scientific instruments, and to the control Each module

At regular

500

constant situation

instru-

control

unit checks

and reformats the commands which then go either to the remote modules or to the NSSC-I for

system signals, and engineering data between the scientific instruments and the SI C&DH. The

cated by these "sating hold"

data

whether

every

computer.

the

etc.),

Engineering

data and passes

trol unit/science

are kept straight.

Remote

or store

sys-

checks,

vari-

+ 12 V; the

control unit, on the other hand, requires + 28 V. The power control unit makes certain that voltage requirements

cess

instrument

system

are functioning.

for engineering

Unit.

scientific

computer

sec, the SI C&DH

unit is on the

tray.

Monitoring.

from

unit

and data processing.

monitoring

vals, varying

interface

coupler

(timing,

or to the SSM 2.5.1.4

unit

processing,

the

ment

if the remote

SI C&DH

monitoring

formats. Ground and SSM com-

engineering and science data. data is an NSSC-I function.

the module

follow

(top

right

in

of drawing)

is interpreted

as "real

time",

as

SI C&DH just received it. Many comactually are stored commands activated

by certain HST tion

memory

stored

this process.

command

if the mands

commands

situations.

is positioned using

Object

program

is activated.

The

systems

to

required

perform

when

SI C&DH such

the

observa-

Spectrograph,

whatever

by a command, to maneuver

example,

for a programmed

Faint

system

the

For

that activates

actions as the

are

pointing

the HST.

science

data back to the SI C&DH. A bus coupler attaches the bus to each remote module.

unit This

2-32

2.5.2.3 Science Data Processing. Science data can come in from all scientific instruments at



SI-UNIQUE MEMORY

COMMAND STORED MEMORY

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once.

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control

unit

transfers

CUIs;_OCESSING

2-37

order, and

switching empty.

between

Each

them

packet

Command

incoming

ence data through computer memory called packet buffers. It fills each

sci-

locations buffer in

as the buffers

of data

goes

fill

from

to the

ground.

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the computer

ting,

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stream empty

control of data,

buffers

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returns

to the control

processes unit

must

either

called

send

full

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unit

transmitbuffers

or

to maintain

SSM. Special

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and pseudo-random

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COMMANDS FROM CDI

COMMANDS FROM DIU

SI C&DH

2-38

for the

SPACE

flow

SUPPORT

of science

data in the

EQUIPMENT

One of the unique features of the Hubble Space Telescope is that it can be maintained or repaired

while

mission-life will capture

a continuous

packet

filler packets,

(Reed-Solomon

can be added

it. When

WORD

I

the

buffer to the NSSC-I for further processing, or directly to the SSM for storage or transmission after

PAR,.,

COMMAND

--

_'_ 27-BIT J %

See

2-3,3

in orbit,

considerably. and stand the

cargo bay, and any maintenance

which The HST

HST

extend

Space in the

its

Shuttle Orbiter

the Orbiter crew will perform tasks required. Maintenance

will require, at some time, exchanging scientific instruments major

will

components.

Major

replacing or and other space

support

FROM CU/SDF COMMAND PROCESSING DMU

TO CU/SDF

LOGIC

r-

TIME

[YH [yH I

CU/SDF

i

Figure equipment

used

during

Flight

The

FSS

Space

Support

during structure

beam,

platform Figure

The

reand

and

maneuvers

the

HST

that

holds

and

arm, which

the

rotates The

berthed or tilts it

FSS super-

components:

cradle

on

The

the out-

with a supporting

and

the

the

rotating HST

FSS

sits

(see

2-39).

cradle

is a two-thirds

to strengthen

in the

bay and

of the held

arm, at the end of the cradle,

oval

with supporting

the FSS. The

FSS is placed

Orbiter

perpendicular

in place

by latches.

beam spans and supports the cradle to mount flight equipment.

to the The and

latch is used

into

rotation

intermediate

toward

rotation

the

platform positions

Orbiter

platform,

to move

cargo

between

up to 140 bay.

the ends

of the

spacecraft. The platcamera embedded in

its base

HST

into the correct

tion on the platform.

The

rotation

platform

rotate

the

360*

once

it is latched

place.

The

units

to guide

The

that

platform carry

orbital

a Spacelab

to the

replaceable hold

two HST

maintenance

Replaceable

pallet to

contains

power

during

Orbital

tainers

the

telescope

equipment

orbital

Unit

with

can in

umbilical

and

support

procedures. Carrier

unit carrier

filled

posi-

(ORUC)

shelves

and

replaceable

is con-

units

(ORUs) for replacement or to be returned. The main components are the pallet, cradle, shelves, support

2-34

the

supports

cradle, holds the berthed form has a small television

2.6.2

beams Orbiter

(FSS), the orbital the ORU carrier,

major

a pivot itself,

The pivot

Structure

side horseshoe-shaped latch

the

operation.

has three

in the HST

are

in place

the servicing

Data

degrees

is a platform

Telescope

Flow of Science

maintenance

Flight Support Structure placeable units (ORU), crew tools.

2.6.1

2-38

structures,

and

latches

to

hold

the

2.6.3

Orbital

Replaceable

Space

Telescope

Units

BERTHIM3

t_TC_ES

FSS

ccrv PIVOT MECHANISM

L_III

designers

selected

modular

ST MAINTENANCE

HST components Orbital Replaceable which were critical as subsystems throughout Units, the

UMBI/ICAL

HST that ability analysis, designers might determined, degrade duringthrough the HST's reli-

I[_"_

STDEPLOY/RETURN

mission

UMB'L_AL

units -- usually a self-contained box with simple fasteners and connectors -could be might need replacing, they werethat designed as

LATCH aEAM _ll/Jt__..

lifetime.

replaced ---C_DLE

easily

replaceable

/ .....

Because

There

in

units

these

one

components

piece.

A

is in Appendix

are 70 ORUs,

list

of

the

E.

comprising

some

26 differ-

/ /

ent components

/

from

the

-- some

small

phone-booth-sized ORUs

are

arranged

tion options -.........

for the

duplicated

-- ranging

fuse

plugs

to

the

tele-

Faint

Object

Camera.

The

into

a series

of configura-

ORU

carrier,

and

servicing

j/

requirements

at the time

will determine

which

ORU option -- and which units in that option -- will be included on a maintenance mission. A Figure equipment has

2-39

within

the

closed-door

crew

aids

FSS

Superstructure

carrier.

The

compartments,

that

can be used

maintenance

(see

Figure

by the

carrier

also

likely which

tethers,

and

configurations

crew

during

2-40).

first candidate have a short

2.6.4

Crew

The

KEEL

LATCH--

k

\

bay, and and

SMALL

\

oRu

the

HST

CRADLE

_ _,_._.,_

FGS _

_

LOADISOLAT,ONJ_.. SYSTEM FLIGHT

and

override

standardized

Space

not HST

Station,

and

Orbiter

drives.

Tools

and

other

only

and

Vehicle. For example, share common features

move

the

for

the the

the

Space Orbital

grappling to promote

uniformity.

STRUCTURE -/ ../'\/'_.,,_ SUPPORT SIPE j / Nv2"_,._ 0 '_,,,.//_ ____,,_

Figure

the

them

equipment,

connectors,

the

extra-

to help

FGE

V\\"_

S,PE

manual

between

Maneuvering receptacles

2-41.

perform

tools

and

bolts,

were

but

many

Telescope

operate

Shuttle, SHELF

Space

equipment

hardware

_I._._

__

will

using

instruments

around

in Figure

astronauts

activity

replace

/SUPPORT /--KEEL LATCH

shown

Aids

Orbiter

vehicular C&DH-_

are

will be the HST batteries, lifespan. Four typical ORU

-J_>

BATTERIES "

\ _ _

"--SPACELAB PALLET

DIRECTION

2-40

Typical

ORU

Configuration

2-35

To get

around

the

HST,

feet

of handrails

that

For

visibility

rails

the

the

crew

encircle are

addition,

the crew can hold

trunnion aft.

bars,

will use

the

painted onto

and scuff plates

guide

225

spacecraft. yellow. rails,

that are fore

In the and

BATrERIES

-_

SINGL

RADIAL FGS MASS SIMULATOR

R FGS

SI MASS

SIMULATOR)

Figure

2-41

Four

ORU

Payloads

There are also portable handhold plates that the astronauts can install where there are not

consuming.

permanent handholds, ance sensors.

sockets

Another use

tool

is depicted

ber

will

crank

a

the antenna

er fail for the mast is

available

if

foot

restraint.

4, in section

procedures.

units have

Other

and on

a jettison the

to the HST. ratchet drives.

crew tnemto

masts,

manually

should

A power

hand-cranking

2-42

they will use suits and tie

Each

wrench

and array

4.3 on

See Figure

are working to the EVA

Its

wrench is

too

powalso time-

2-36

hand

tools

handle,

aperture

wings so the crew from the HST.

in Chapter

the astronauts to hook tools

replacement

as on the fine guid-

is the portable

HST maintenance for an illustration.

While tethers

such

lights

door

include which and

portable attaches solar

can push the equipment

to array away

Section THE

The

scientific

Space

Telescope

(FOC), the

instruments

the

are

Faint

Goddard

(GHRS), and

the

PC).

FOS,

GHRS,

a

scientific

scientific and HSP optical

axis so that

can

fit into

the

focal

parallel



to •

apertures. dimensions

are placed

and the three just

forward

of the focal

sensors

plane

in the optical

the incoming entrances.

No scientific in the

focal

plane,

instrument Space falls

make

Telescope directly

tics and

because

detection

small

of the beam.

instrument

This

ferent

filters,

entirely

devices

gratings,

separate

instrument The

astronomy

is called

or

optical

to break

filters,

gratings,

for the GHRS

team

the

can

prisms

systems light and

the

locking

in the selected

other

them instru-

target.

and positioning

and

onto

the appropriate

devices

needed

fil-

to modify

the

light.

Exposing the instrument's detector light as long as needed to make the measurement.



Processing transmission



Analyzing for further

the collected to earth.

to the desired

information

the data and using observations.

for

the information

of each astronomical

scientific targets,

up the rest of this chapter.

The

tion of the

sensors

fine

guidance

instrumake

astrometric

func-

is included.

light

The

optarget

into other

are Operated

select --

THE FAINT

OBJECT

CAMERA

the FOC,

more

than

the other

use the

optical

resolution

objects

in deep

space

fore.

observing

and

aperture

to acquire

Selecting

3.1

acquisition. The

FGSs.

a large

Physical descriptions ment, and possible

But each

so the incoming

system.

stars

of:

size of

to adjust

specified

the

Using

consists

the pick-off

calculations

the

and

of data.

of

all of the light

of the

position

onto

part

respective

or because

up only part can

their

receives

aperture

pick

to deflect

into

instrument

the instrument mirrors

path

light

mechanics

collection



struc-

ture, at right angle to the optical axis. These four radial instruments rely on pick-off mirrors positioned

using

incoming

structure

fine guidance

process guide

ters

interchangeably.

The WF/PC

the

Control

unit's computer. own small com-

instrument

process

Selecting

ment

the incoming

plane

Instrument

(SI C&DH) have their

operate

and

The operation

the FOC,

-- are located

will fall into their entrance instruments share the same

so they

sensors

--

that

monitor

astrometric

instruments

Scientific

(WF/

guidance as

puters

(HSP),



the telescope's images These

Spectrograph

role

in the

& Data Handling Other instruments

(FOS),

Camera

fine

embedded

Camera

Photometer

Field/Planetary

(FGS) have instruments.

of the

Object

Resolution

the

INSTRUMENTS

in the Hubble

Spectrograph

Speed

addition,

Four

Faint

Object

High

Wide

In

the

High

the

placed

SCIENTIFIC

3

The

FOC

of the HST

more

or

even

able

-- within

one

FOC

to detect

examine

mechanical

and

by software

Solar

3-1

the light

will study

a spectrum.

System.

locate

and

to record

than

to capture

will

ever

be-

celestial

to 28my, which is so observatories are not from

the evolution

galaxies

possibly

clearly

will be able

lights with a magnitude faint that ground-based

dif-

instruments,

faint

planets

those

images.

of star objects existing

The

formation,

like quasars, outside

our

3.1.1

Physical

Description

secondary then

The FOC

was designed

by the European

in

West Germany and British England. Its physical dimensions

Aerospace in are 3 × 3 × 7 ft

used

(0.9

size

(ESA)

and

built

× 0.9 x 2.2 m),

phone has

booth; four

structure and

roughly

it weighs

major

the

about

The

houses

bench

head

assembly

that

supports

mechanical

equipment.

assembly handling

holds the equipment

elements.

main

optical

the

The

bay

and control.

of the

photon-detection

system,

data-processing

elec-

The

major

Figure

After

supply

the HST is positioned

light,

is focused

which

channeled

consists down

image

of many

one

At the end of the the FOC detection recorded

on the FOC

is placed

and can be intensified data is transmitted

3.1.1.1

Optical

FOC

using

consists

of two

optics

systems

incoming

light

FOC

aperture

scope

that

reflected

data

system

independent

in the

travels

through

into a small

a primary

same

that

out

light obser-

a mirror

of light coming

way:

the

the field

the

same

from

on

a cali-

light and geometby the FOC can

the

of

HST

because field

allows

the

objects

only 0.01

globular

on

ratio

the

FOC

to

which

apart.

the

stars

appear

It

can in-

is a tradeoff, system

(22 arcsec)

distinguish

that ground instruments between them.

Both

in the path

f/96 optical

arcsec

produces

resolution.

There

at best

for studying cluster,

main-

of f/24 four-fold,

inserted

of view,

while

system

best angular

up to f/288.

narrow

requirement

This

focal

device

that ratio

option

resolution.

System.

Telescope's

a special

of view light

spectral

increases crease

ratios,

has a 2, but it

between This

two

is a crucial

within

a distant

so close together cannot

distinguish

selected

Cassegrain

concave

length length,

a shutter

is closed,

to visible produced

the Space and

systems, focal

to the f-stops

telescope.

focal

systems there is a zoom

optical

The 1'/96 Optics

an image

optical

operate

for

optical

physical

has

the shutter a beam

doubles

taining

store

for the larger ratios.

is like the main from

that

is

pathways.

into

are similar

except

and

In both

The

photons,

in a science

and

the

FOC's

aperture

The FOC response ric light distortions also be determined.

each photon enters and is detected. The

apertures

These

cameras

energy

The

increase the

system

When

however,

System.

two different

f/96 and f/48. earth

in

aperture.

graphics

optic

it can reflect

by a longer exposure. The to earth, where it can be

enhanced by computer of the celestial object.

the

light from

of two optical

pathway device

beams

3-2 for

bration source down the optic path to measure the light-detecting capability of the detectors.

pictured

correctly,

mirrors

increasing

vations.

3-1.

an object

the

are

wavelength

Figure

wheels

remains closed, completely blocking until the FOC is needed for astronomical

for the detectors.

subsystems

folding

Each

dataThe

is composed

power

processing. filter

and

assembly

and

and

contain

onto the

move to adjust the focus, and correct for astigmatism in the HST telescope mechanism.

optical

photon-detector tronics,

See

plane,

and finally

enhancing

critical

studies.

without

The

electronic

data-processing and system

for

pathways

to isolate

The

elements an

on a different

mirror,

kg). It

loadcarrying

contains

tube optical

specific layout.

of a tele-

the optical

photon-detector

optomechanical

System

700 lb (318

subsystems.

assembly

the

by Dornier

mirror

a folding

detector

Space

Both

Agency

convex

onto

tele-

The

The light is mirror

block

to a

f/96

unwanted

coronographic

3-2

optics

have

two

light from fingers

special

features

to

the field of view:

two

in the

aperture,

and

an

OPTICAL

BENCH

OPTICS

PATHWAY

INCOMING

LOAD CARRYING STRUCTURE

Figure apodizer

mask

optical The near

can be moved

3-1

FOC

Major has

into the f/96

fingers the

can target

block

bright

of the

FOC,

can be detected is useful

ELECTRONIC ASSEMBLY

Subsystems a faint

companion

when

objects

that

so the

targeted

with less intrusive

observing

a bright

It is near

light.

star

the edge

the smaller

that

PLANE

_//_-, _L_t0_mm/

ST A_I /

_

of being

a

B_-__

device

finger.

that blocks

but includes The

apodizer

out stray light re-

off the secondary

support creases

structures. The Cassegrain system the focal ratio to f/288. This narrows

field of view even WHEELS

f/96 FOV

flected

olution FILTER

of the

coronographic

embedded telescope.

mirror

and

ST optical inthe

MIRRoRPRIMARY

/

/-

SM_RCRO(_g ARY

suspected

The high-resolution apodizer is within another miniature Cassegrain

are

is a masking ST FOCAL

BAY

planet.

path.

object This

which

PHOTON DETECTOR ASSEMBLY

FOLDING

needed

by brighter almost

to detect

ones.

The

only

able

one

but increases faint

FOC

17 magnitudes

companion being

further,

objects

can detect

fainter arcsec

to see a dim

star

than away.

the resobscured an object its bright

This

is like

in full moonlight.

REFOCOS MECHANISM HODE CONCEPTUAL

LAYOUT

OF FOC IMAGING

Another feature in the f/96 optical path is a series of four filter wheels, which contain 48 fil-

MODES

ters, Figure

3-2

Layout, FOC Relay Systems

Optical

3-3

prisms,

and

example,

if the

send

beam

the

other

optical

astronomers through

devices.

choose,

they

a magnesium-fluoride

For can

prism to emphasizethe spectrum. optical

See

Figure

far ultraviolet

coming

end of the

3-3 for the complete

ing.

f/96

This

trum

layout.

through

The f/48 Optics

System.

This system

will allow

a

wider

field of view at (44 arcsec)

2, but the reso-

lution

will be less than

f/96 optics

sys-

thus will be reserved

for

tem.

The

f/48

system

with the

spectrographic

purposes,

target

and as a secondary

searches,

To use the f/48 may need light path

system

other

duties

such

optics

the HST orbital

The

as

of the f/48

are

two filter wheels, detector.

and

a detec-

The

also has a 20-arcsec-long

spec-

troscopic rotated

slit in its aperture. into

the

optical

A special

path

diverts

High that

AND iT OPTICAL

MIRROR

the

Faint

slit has

a limited

resolution Object

many

light

The

light years,

optics

also

include

can be used either

sources

two

filter

with the main

_- PRIMARY

MIRROR FILTER

WHEELS FOLDING

MIRROR

-_

REFOCUS

SECONDARY MIRROR

SOURCE

LIGHT

PHOTOCATHODE

Figure

3-3

F/96

as a

wheels, optics

or

with the spectrographic optics for specialized viewing. The filters can, for example, block out

light

/-

THE

spec-

such

7

CALIBRATION

and

FOC

AXIS

_1_

is

falls

Spectrograph

I

INCOMING

quality

is in measuring

across

light

register specin the 2000-A

or nebula.

f/48

which

SHUTTER

6.6 arcmm

dis-

spectral

of the diffracted

Spectrograph.

value

spread

galaxy

REMOVABLE CASSEGRAIN FOR fl288 WITH APODIZING REMOVABLE

a specThe

detector.

spectral

Resolution

trograph's

mirror the

grat-

into

into the

resolution

This

between

The f/48 system

reflects

spectral

range.

the

reflecting optics, tor like the f/96

light

light

wavelengths.

2000, which means the detectors tral lines only one angstrom apart

position

system

the

composite

spectrographic

The

relay.

to be readjusted to redirect the main into the f/48 aperture. The f/48 optics

components

breaks

a diffraction

range, depending upon the spectral order chosen. It ranges from 3600 to 5400 ,_, for the first order to 1200 to 1800 ._ for the fourth order.

system is identical in overall structure to the f/96 and shares the same calibration device. The separate

grating

of the

persed

the slit onto

f/96 OPTICAL

Optical

3-4

RELAY

OF THE

Relay

System

FAINT

OBJECT

Layout

CAMERA

certain

wavelengths

length

ranges.

optics

or select

Figure

very specific

3-4

is the

photon

wave-

detailed

burst

f/48

layout.

recorded 3.1.2.2

The

Photon

Detector

System.

light

There

minutes

A,. The

science

image verted the

reconverts tron.

in three the

An

for every

an

trates

the path

stored

enter

center in

image

the

an

original

amplified

processing

is produced

detector

signal

Figure

from

of

by the

video

science

each

to the

3-5

the point

photon

processing

data

store,

depending

object

being

store upon

extremely the

exposure

The size of the completed

illus-

the

when

light

light

pixels, burst unit q_ically

size

format with

originally is a square each

is and

ly-shaped doubled.

LIGHT

a

,-_

PHOTOCATHODE

_

THE

Figure

3--4

to

observation. magnitudes

last

up

to ten

F/48

pixel

picture selected. measuring 25

by 25

depends The

upon

standard

512

by 512

micrometers

lights, and the pixel size can be This will affect the number of photons

ANO M...OR 7

_'1

up

location,

with

may

the The

(1/10,000th of an inch) in size. Other formats can be chosen for larger, smaller, or different-

-P.,MARY M,R O

"-_oRINCOMING

each

of the

objects time

upon

or record

at

the length distant

ten

observed.

will count bursts

An

between

tube,

to its processing.

location the

video

hours,

position.

by a

camera

unit.

of a photon

elec-

ten

photon

to 28, hours.

pro-

at that

in a period

of the data

depending For

is intensified

and

65,535

detector

to photons,

television-type

sends

determined

Then

photons

intensified

video

it hits the

steps. output

100,000

FOC

The

source

electron

high-sensitivity which

the target

intensifier, where the photons are conto electrons. High voltage accelerates

electrons

viding

from

light

brightness

75 to 100 microns

Every time an incoming photon the diodes at the same location, the

can be produced

are two identical detectors in the FOC. They are sensitive to radiation between 1150 and 6500 photons

is a spot roughly

in diameter. bursts onto

Optics

3-5

FI48

Relay

OPTICAL

System

RELAY

Layout

PHOSPHOR--_

PHOTOCATHODE \ \

3-STAGE INTENSIFIER INCOMING

-_

_

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_

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w,,,DOW= \ HOT-BIALKAL_r_c

READING

PHOTOCATHODE

(NSSC-I), the & Data Handling

with the

FOC's

3.1.2

RELAY

I

LENS

I

A

v_

standard

spacecraft

Scientific Instrument unit computer which,

on-board

computer

as a back-

the FOC.

Observation

Modes

I

i

I,v

NASA

computer Control

up, operates

/

__

to the

4

The

I SCIENTIFIC

I'.?;_'_L''

I DATA

Faint Object

modes:

Camera

targeting,

has four observation

imaging,

occultation,

and

spectrographic. Targeting Figure

3-5

Photon

Detection

the FOC can count because transmission limits. One

advantage

light

in the

data

any time without lected.

This

study

of the

system

store

destroying

is quite

and

the data for

being

target

cated

at

light is stored

tape

recorders

until

Telescope (STOCC) ellite

it can be sent

Operations

System

and

image

by the HST

FOC

process

cludes

transmission

Data

Relay

the FOC

final step

support,

support,

body

Sat-

omers

in the

which

dataprocessing,

and is performed

tronics system. tronic functions, keep

The

is electronic

physical

uses

in-

is the

linking

the

FOC

and to

optics

elec-

protected

communications the

Space

Then

of view.

optics

system

Various

for-

change

the

to

wavelength

units

can

range.

fingers

study

the

would within

3-6

and

one

the

a bright surrounding

a galaxy

celestial mode

uses

high-resolu-

object

be occulting

so astron-

background. a quasar

visually

to see

obscured

by

brightness. mode

f/48 aperture

to diffract

composite

wavelengths.

ranges

of

Occultation

Spectrographic

to separate

Telescope,

eclipsing

object.

cross-dispersing are command

of the

of a target.

to occult

the quasar's

in space. There

field

selected

the

by another

if it exists

and

by the FOC

and

of view.

FOC

either

are

size and/or

An example

The system also services elecsuch as the thermal control to electronics

field

to place the light onto the or spectrographic slit, lo-

image

the coronographic

Electronics.

FOC

of the

filters

Occultation

Center

(TDRSS).

FOC

the

a direct and

tion apodizer 3.1.1.3

or spectrographic

to the Space

Control

via the Tracking

mode

to take tape

within

on the edge

Imaging

intermediate

light.

on magnetic

us-

col-

mats The

any observations

coronographic

the HST is repointed coronographic finger

is that the

can be viewed

useful

developing

storage

precedes

devices. A special exposure of the target, using the FOC, is processed by the SI C&DH to find the

of the detector

science

ing the FOC's

System

of data

mode

uses

prism the

for specific

light

the

long

the incoming Filters will into

study.

slit in the light

into

and

allow

astronomers

narrow

wavelength

a

3.1.3 Faint

Object

Camera

Specifications



Providing various

Table

3-1

Faint Object Specifications FAINT-OBJECT

Weight Dimensions

possible

dust referred

visible

as huge clouds

ample

of these

Magnitude Range

5-28 m v

in the

Horsehead

Wavelength Range

1150-6500 Ang.

Focal ratio can be adjusted from the ground. The most be f/96.



The

clearly

imposed

focal

The

wavelengths

band from

1200

and

maximum

range.

concentrate

to 1800

Angstroms.

ratios

depend

Object

will For

light

upon

times



be

Studying

Measuring ies and



Examining irregular

pattern

Figure

3-6.

a

exam-

to inter-

Courtesy

observation

but

indicate

will be used,

with other

on a number

Among

relating stars •

Camera

in conjunction

tions.

dark-cloud See

on the band

(clear

and exposure limits.

struments,

is the

Nebula.

ex-

for

Figure

the

Observations

The Faint

clouds

and

A good

for

Stellar 3.1.4

matter

in the heavens.

limi-

itself. maximum

usually

may

signal-to-noise

ference) ranges FOC's

studied

the

study

Specific

to as interstellar

specmicro-

ratio.

within one

except

by the optical

of the Space Telescope of view listed are the

each

ple,

discussed

as commanded frequent use will

will be resolved

light halos

tations Fields

of

NOTES:



light

are

3.1.4.1 Stellar Evolution. Astronomers ulate that stars form out of the gas and scopic

slight

observations

phenomena

explorations

ESA (Domier, Matra Corp.) f/96 f/48 11,2. 22 arcsec 2

SPECIFICATION



resolution

System

CAMERA

3x3x7 ft (0.9x0.gx2.2 m) ED. Macchetto, Eur. Space Agny

Optical Modes Fieid of View



These below.

700 Ib (318 kg)

Principal Investigator Contractor



Camera

high Solar

of important

its priorities interstellar to the

formation

and

observa-

for evidence evolution

waves

coming

explosions,

in-

are: gas clouds

of the farthest

Astronomy

scientists

clouds from

are

believe,

and from

from

the whirling

Growing

hotter

galax-

and

supernova movement

of

This violent motion onto themselves.

and heavier,

in a nuclear

shock

newly-formed

stars,

of spiral galaxies. the gas clouds

begins by

the clouds

ingly compress into a spiraling mass around a dense core. Eventually

of

Observatories.

buffeted

nearby

the arms collapses

ignites the distance

gas

internally-combusting

by itself

HST scientific

formation, the

Optical

The Horsehead Nebula, A Dark Gas Cloud

3--6

when

National

explosion

and

increasof matter the mass

become

a

protostar.

quasars globular

clusters

and normal

and

Unfortunately,

galaxies

in

3-7

development

clear

observations

is difficult

of a protostar because

of

the

surrounding

mass

"cocoon."

When

explosions

blow

gas,

leaving

ing

gaseous

clumps, develop

of

matter,

a new star away

only

often

begins

much

scattered

called

a

igniting,

of the clumps

objects

orbiting

the

astronomers into planets.

theorize,

could

these

the

process

team

obscuring

tions

a clear

planetary

matter.

and dark

clouds

star.

background

These

eventually

Certain

stars

for planets mers have

cloud

from

months,

hold

special

with prethe camera

the FOC

Figure

3-7

may

picture

starlight. angles,

the existence a planet.

capabilities

a muddy

But,

by

rendering

of the FOC of the

taking might

images be able

See Figure

of

the

of a

Observa-

because

the FOC

any faint companions.

artist's

3.1.4.2 tent of

Measuring Distances. the universe? What

between

stars?

is an art-

interest

in the

search

to

3-8 for

photographic

Protostar

ability

What is the

is the exdistance

with its high

to detect

objects

angular light

previous calculate

observations, will help direct geometric dis-

to astronomical and parallaxes

objects. By examining for clusters of stars,

along with the speed at which material is dispersed from the stars, astronomers can accu-

System. Astronoin the motion of

3-7

The FOC,

and

years beyond astronomers tances motion

Figure

the masking

different

resolution

with preplanetary

our Solar variations

perhaps

technique.

of this

protostars

using

equipment,

of a protostar it.

that suggest

fragmentation

candidate

changes.

beyond observed

as much

view of a protostar

over

dynamic

ist's conception matter circling

from Studying

and its spectrographic capture

to observe

as possible,

to, perhaps,

using

will produce

isolate

hopes

stars object,

of condens-

an The FOC

single

companion

rately

measure

with Preplanetary

3-8

distances.

Matter

central regions mayreveal the sourceof that intense radiation. Of particular interest is the center of galaxy

NGC

(Figure

3-9).

sive object sions

4486,

object,

at its center,

An important

measurement

magnitude

astronomers the

Cepheids

of

different

measure

the

in the

Large

Globular

ety of galaxy

types

precise

distance

Magellanic in more

Clusters

and

globular

clusters,

Couflesy

to

Cloud, distant

will be used to seek which

radiate

ing galaxy with

clumps

center hension?

A

answers.

Figure

the

than

from

the

the center

tre(Fig-

massed

object

sized

high-resolution

Clus-

the

f/48

program using

broad-band

Optical

Astronomy

The Elliptical Messier 87

observation center

National

Galaxy

would

the f/96 optics

filter,

and

the

Observatories.

examine

the

system,

with a

spectrographics

of

optics.

Many quesand galaxies, instruments

The

con-

together? beyond study

The cover

masking these

filled

may

have

Is the

they

and

compreof

also

will concentrate

3-9

of the

faint

galaxies.

formed

shortly

about the early of the universe.

these

luminosity

ability

their

on known

are surrounding

den by the tremendous

surround-

centers

FOC

sars to see if there

and galaxies, the

bright

3-9

sys-

and a vari-

One question

clusters

energy

Are

of stars

a massive

clusters scientific

of some

more

itself.

Galaxies.

fill the universe.

tions arise when studying and the FOC and other cerns the centers

radiating

is a single

producing

Once

galaxy called

If the center

or pulse reguAstronomers from the rela-

The

ters of stars,

colli-

The clouds known as

Cepheids.

they can measure Cepheids tems more accurately.

3.1.4.3

by stellar

that add to the grow-

indicator

Magellanic Cloud. distance indicators

Cepheid variables, which radiate larly at two distinct magnitudes. can calculate relative distances tive

created

matter

is a mas-

"Photographing "A Secondary Body

distance

will be the Large contain standard

there

be a quasar

mendous energy ure 3 - 10).

3-8

suspect

of the galaxy.

it could

elliptical as Messier 87

known

Scientists

and collapsed

ing nucleus

Figure

also

galaxies

may

composition

FOC Since after reveal and

qua-

galaxies

hid-

of the quasar. may

help

many the

dis-

quasars

Big Bang, information

development

Figure 3.1.4.4

Examining

With

the

planets, the

FOC,

Quasar

Solar

System

astronomers

moons,

Solar

3-10

can

asteroids,

System

and

more

Hypothetically Objects.

observe

other

clearly

planets.

the

bodies than

spacecraft.

But the FOC

astronomers

to examine

a planetary

in

from

years

of the brief

time

instead

ager's

"fly-by"

tions,

moreover,

FOC

cannot

light

trajectories.

interference

place

faint

from

dictated

Planetary

can take examine

will allow object

tary moons

in greater accurate

tion,

orbits,

will

study

3.2

example, of

will advance

Martian

Mars

of the

wind

formation;

movement.

Closeups

tune,

Uranus,

and

edge

of the

surface

FOC

outer

when

the of

The

of Mars, such

storm

velocities;

seasonal

polar-cap

Saturn,

will expand

composition

Faint

and satellites

will allow

asteroids

detail

than

and plane-

ever The

using

before

axis

composition. its

to

orienta-

FOC

also

spectrographic

device,

and

a variety

Spectrograph

High

Resolution

are

Each

FOS

3-10

faint

but

objects

the FOS

while

in much

they

overlap

up each

detecting

the

greater

to different

is a medium-resolution faint

The

objects,

light

to back

and

Spectrograph

sensitive

spectrum,

For objects

the range resolution

of these

brighter

of the

(FOS)

instruments.

very

is most

in mid-range

range.

that the

from

tions

captures

dynamics

companion

what The

Nep-

SPECTROGRAPH

Object

studies

detail. as

OBJECT

light

GHRS

our knowl-

and it is possible

additional

for

understanding

of Jupiter,

and

Goddard

or moon.

weather,

dust and

Pluto

planets,

may discover

and and

white-cloud

on these

scientific

geography patterns

surface

resolution

dimensions,

comets

FAINT

studies observation

angular

of the smaller

determine

(GHRS) Direct

FOC

by Voy-

because

the sun, earth,

The

87

optics, the coronographic of filters.

for

observa-

even

objects

In Messier

examination

ground-based observatories. Scientists will obtain data similar in detail to that obtained from the Voyager

Centered

porsome-

other.

instrument. a broad

with apparent

22 and 26my, the FOS of 250. This means

It

spectral

magnitudes

in

has a spectral that in the

1500-Angstrom tral

lines

range

as close

brighter

objects

1300,

it can differentiate

as six Angstroms the

separating

resolution

spectral

to 8000 duce

A,

very

objects,

in the broad

velocity

the

of celestial and

mer

can help

hot,

X-ray-emitting

stellar

discover

dust

passing

also

intensity

the

internal

clouds,

through

The

has

The

aperture,

The FOS

acquisition. various

for

Four

optical

axis.

Research

Corp.,

Marietta

the

one

through cillate

are

light

the

was

paths

leadership

built

travels

a prismatic degrees

of

light

of Applied

mirror,

goes

which

from

the

through

an

and

--

all light

longer

than

6800

The

The

(blue)

See

detector

wavelengths.

of the optics;

communication

support

ics equipment.

pass through can rotate plane

so

passes

for the

optical

Figure

3-11.

electron-

systems; and

the

onto

beam

optical

axis.

wheel.

22 The

order-blocking

waves

short

structural

os-

filter This filter

passes light in the desired spectral range. For example, if that range is 4500 - 6800 A,, the fil-

objects

Digicon

reflects HST

on the filter/grating

back

consist

if they

the analyzer

light

waves

aperture

off a collimating

and

the

Light

the selected

beam

components

send

through

flects

power,

shield.

in increments

for

ics,

as galax-

for spectropo-

in a certain

and for

FOS

such

are selected

away

mounted

by Martin

in the instrument

to a red-sensitive

emitting

sky One

planes

longer (red) wavelengths, a blue-sensitive detector

leads

targets,

plane

sources emitting the other leads

one

and

of view.

to act as a light

analyzer.

and

a a qua-

target

specialized

polarized The

the

apertures

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occulting

surrounding

fields

for wide is blank

in a particular

Light

Corp.

are two optical

observe

is

apertures Two

surrounding

different

These

a magnetic

in diameter,

light

a galaxy

a polarization

ter blocks There

faint

apertures

larimetry.

infor-

to the HST

President

FOS

of

of 12 apertures.

The smaller

(e.g.,

serves

Three

X-rays.

the light

parallel

under Vice

one

down

of 22 degrees.

680 lb (309 kg), and now

Pointing

light

observations.

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ies, while

3 x 3 x 7 ft (0.9 x 0.9 x 2.2

Designed

operating.

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apertures

aperture

for-

Description

m) and

R. J. Harms,

sys-

a filter/

detectors.

4.3 arcsec

capture target

background

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can polarize

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only

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and

for target

sar).

them.

Physical

begins

the incoming

paths

through. 3.2.1

optical

mirrors,

port leading to the aperaperture port remains

the FOS

two optical

bright

cooler

reveal

processes

which

FOS

and the separate

places

apertures

between

by the

observations

about

of

and

and their

bombarded

until

the HST

(wavelength

stars

The

apertures,

is an entrance assembly. The

closed

the

FOS

capabilities.

binary

Spectropolarimetric stellar

nature

the interactions

companions

mation

The

of light)

wheel,

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measure

spectropolarimetric

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a

will pro-

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chemical

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and

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System.

special

components

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targets.

spectrophotometric of light)

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the

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to

of targeted

of the chemical

to studying

objects,

This

portraits

this spectral

of most

In addition faint

infrared.

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tem contains

as 1.2

the FOS can display A, in the ultraviolet,

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near

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3.2.1.1

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spec-

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tion

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objects

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detector

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data

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several

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one

3.2.4

Observations

The

FOS will observe

many

of the objects

being

targeted by other Sis, but for different information. Three observation plans being considered would study galaxy formation, can be used to test distance composition

and

3.2.4.1

Explosive

theorize

that

ies, and

of interstellar

Galaxies.

quasars,

the Milky

stages

quasars

Seyferts

searching

Astronomical

exploding

development.

recedes

from

galax-

The

as

FOS

galaxies

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like the

for relationships.

repeatedly expand

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may be related

and exploding

data

which

dust.

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Way galaxy

in galactic

examine

they

origin

how supernovae formulas, and the

from

expel

quasars

indicate

nebulous

rapidly

as

the

us at speeds

that

clouds

of gas,

entire

quasar

approaching

light. Extremely distant quasars are billion light years away. Astronomers

that

of

nearly 14 believe

these distant quasars may have existed since the earliest formative stages of the universe. If so, nebulous could

matter

surrounding

be the beginning

Exploding

galaxies,

the

center.

are expanding

the

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jets

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matter

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At least

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to quaoff from gas

at high velocities,

exploding Figure

development.

as Seyferts

emit

clouds

quasar-like

quasars

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that

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these

two

from

the

examples

of

galaxies. Courtesy

The

FOS

sources,

team

and

for chemical late these

the and

earlier

its whirling,

left),

and

study

clouds

physical galaxies

nebulous

tistic comparison quasar (top left), (lower

will gas

these they

energetic

eject,

relationships

Figure

that

Figure

Milky

3.2.4.2 vae

3-14 is an ar-

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Astronomy

Observatories.

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are

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right).

3-14

and

dramatic

evidence

active.

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violently

of the four types of galaxies: Seyfert (top right), elliptical the

Optical

Two Examples of Exploding Galaxies

looking

to the Milky Way, with

arms.

3-13

National

gasp the

of a dying

star

supernova

erupts,

Distance. that

the

is the such

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most

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is

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Figure

remaining leaving

matter behind

a dwarf

ever, don't know va explosion.

With

the FOS

can examine practically thereafter. magnitude, magnitude

scatters

3-14

into

star.

the exact

the

heavens,

Astronomers, details

x.__.

Galaxy

3.2.4.3

supernovae as the nova Luminosity to calculate

to measure occurs and determines the

for

A planetary

su-

de-

FOS

will

will provide different

3-15

producing

distant

eons

that

and mass

anal-

planetary

in the history

a subject yield

the

of stellar

of

3-15.

will

nearby nebulae This particular

a portrait

shell

Figure

with

light

chemical,

material study

See

astronomers

temperature,

of the

faint as 22my, and Magellanic Cloud.

magnitude measurement Law to better estimate the constant H. A conclusive

star.

of ultraviolet

yses

It grows the star's

as an expanding

the dying

provides

studies

accurate

termined by the against the Hubble value of the Hubble

supernovae

of Stars.

into space

A nebula

apparent

the distance

Evolution

gas encircling

periodically absolute to the

The

atmosphere

luminosity

with

distance

can then compare

the study of many Space Telescope.

nebula is a remnant of a supernova. large and cool until stellar forces blow

astronomers

is compared

Types

answer requires with the Hubble

how-

pernova.

Astronomers

of Four

of a superno-

spectrophotometer,

which

Comparison

light.

The

nebulae

as

in the Large comparison evolution

of the

universe.

from

Goddard

High

(GHRS). Center,

Spectrograph

Developed by Goddard Space Flight under the direction of J. C. Brandt, it

was built

by Ball Aerospace

Ultraviolet sphere

Resolution

rays rarely

but have

servatories

pierce

been

most

Ultraviolet

The

GHRS

than

the

is more

IUE,

the

examined

in space,

national

Systems. earth's

before

recently

by the

Explorer

(IUE)

sensitive

to faint

to 17my,

though

atmofrom

not

ob-

Inter-

satellite. objects

as sensitive

as the FOS. Much more importantly, the GHRS is far more accurate and has greater spectral resolution than the IUE. Palomar

Figure 3.2.4.4 ter. One

3-15

ally attached is the dust. particles

material

3.3.1

Nebula

scopes.

invisible

Astronomers in great

--

The

FOS

clouds,

netization. mation

for

of the

dust

hope

findings

about

fil-

much density

about

clues

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and

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studies

the

far fainter

star

hand,

mation

ment

designed

the

objects universe.

for ultraviolet

objects

The

differ

in and

in sensi-

GHRS

differences

objects,

down

can

between

resolution

of

to 26my.

Physical

scientific

compositional in spectral

infor-

detail.

Description

also

is aligned

axis. Sized

parallel

produces

will tell

closed

spectra,

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GHRS

support

and a structure The

computer

to the

HST

at 3 x 3 x 7 ft (0.9 × 0.9 x 2.2 m)

and 700 lb (318 kg), it contains

SI C&DH

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electronic housing unit

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handles

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functions.

and The

the vast gas clouds observation

will produce

unprecedented

3.3.2

Telescope

temperature,

and

separate

for-

that

Space

up

func-

gas clouds

The

to a spectral

other

to the

RESOLU-

from

the Hubble

the composition,

of stellar

throughout

radiation

using

they

resolution.

lines,

The GHRS

(UV)

astronomers

because

spectral extremely

thermal Ultraviolet

and

spectral

tects

polar-

process. THE GODDARD HIGH TION SPECTROGRAPH

in some

But they also serve

resolve

optical 3.3

stars

Spectro-

For a broad spectrum and a variety of star distances, the FOS stands out. The GHRS, on the

light

looking

overlap

as measuring

functions

and

Object

100,000, but only for objects 13my and brighter. The FOS is more limited in resolution but de-

magnetism.

Astronomers abundant

light

such

ultraviolet.

tivity

with Faint

spectrographs

valuable

the dust col-

becomes

ultraviolet

composition

produce

the

tele-

because

clouds

of strong measure

dust

chemical

fields

the dust

can

that

two

tions,

not gravitation-

ground-based

theorize

evidence

through

to

magnetic

through

ized

in space

Comparison graph

The

to a star -- that remains unstudied The reason for this is that the dust are

tering

Photograph.

The Composition of Interstellar Matelement of the interstellar medium --

the cloud-like

lects

A Planetary

Observatory

optical

rotating

instru-

carrousel

wavelengths,

is the

3-16

system

contains with gratings

mirrors

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two

apertures,

to separate the

light

a the

into

a

specific detector, and two Digicon light detectors, one for 1050 to 1700 A, the other for 1150 to 3200 ture

A,. See Figure

and

optical

3-16 for the GHRS

The

large

science

aperture

is used

to locate

the

target, observe galaxies, and perform spectrophotometric and spectrographic observations

struc-

system.

when

precise

spectral

The

small

light

of single

resolution

science

is not required.

aperture

objects,

captures

the

such as a star, and

full

is used

to obtain the GHRS maximum specified resolution of 100,000. This means that in the 2000/_ range

the

GHRS

separated

_y

CAMERA MIRRORS CONCAVE

DETECTOR

small

aperture

large

aperture.

Two

slits

_

CONCAVE

wavelength

_(__._

CROSSDISPERSER GRATINGS

the

ENTRANCE APERTURE

1

in the

needs

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and

starlight

blocks

the

provide

accurately

starlight,

UV

light

the

They

are

the

be meaare

called

compared

with

very accurate

wavelength

PARABOLOID

turn, will provide the composition

a crucial step in calculating of stars and the speed with

which

toward

they

move

These

UV

COLLIMATOR OFF-AXIS

2

readings.

can

wavelengths

to produce

Lamps

through

wavelengths

These

standards.

incoming

DIGICON

these

the

for comparison.

shine

precisely.

When

area

incoming

standards

features

a shutter

To measure

of

in the

spectral

angstrom.

aperture

calibrations.

calibration

/s

GHRS

wavelength

sured

f

of an

is operating,

GHRS two

DIGICON

will display

by 0.02

measurements,

or away

from

in

us.

SHUTTER FOR LARGE SLIT INC( LIGHT

"GRATING MIRROR

The incoming light reflects mirror that directs the beam

AND CAMERA CAROUSEL

TRANCE SLITS

Figure

3-16

GHRS Optical

Structure System

and

3.3.2.2

Carrousel.

wheel

with

seven

acquisition

Apertures.

tures, arcsec ence

a large across aperture

the FOV. The

The

science its field that

GHRS

two

0.25

arcsec

through

ture

the divergent

points

is astigmatic. of the light,

at right

angles

To adjust each so the

2.0 sci-

0.03

aperture incoming

each

and

coarse

and

and

select motor fine

three

specific rotate

the

positioning

The

carrousel

to position

See

Figure

The

carrousel

can

move

the right grating

in either or mirror.

3-17.

aperfocal

has two slits set lights

arcsec.

direction

across

are not on the HST op-

tical axis, so the light coming

to

steps, to direct a desired wavelength to a detector. The carrousel motion is accurate to within

aper-

aperture measuring of view, and a small

measures

apertures

has

through

is a rotating

gratings

used

An encoder

carrousel,

a collimating the carrousel.

carrousel

diffraction

mirrors,

wavelengths.

3.3.2.1

The

off onto

tings,

merge

ject.

again.

used Two

diffraction.

3-17

has

to lock settings The

three

mirrors,

the HRS reflect other

onto faint

with four

set-

the desired

ob-

objects

two settings

allow

with

no

bright

tion

increases,

electron

the

count

intensity

drops.

spectral

resolution

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longer

decreases

This means a celestial

to

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and

the

that at higher object

enough

must

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energy

to

GRATING

The

spectral

frames

G;; G

resolution

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(middle)

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from

2000

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ber of spectral between 1475 cally

of the

ranges

spectral (top)

(bottom).

The

to

num-

features measured in the range and 1480 A, increases dramati-

as the wavelength

range

shortens.

G 270M ACQUISITION

The

MIRROR

grating

carrousel

sends

mirrors, Figure

3-17

GHRS

Carrousel

up to -1my,

to be targeted.

which

The

latter

the

incoming

light

for analysis. observe

carrousel into

GHRS

the UV (20,000),

lution.

The

highest

tained

with

two

or high

overall

spectrum

example, Grating range just 29 A displays details

Figure

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along

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the detection

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by each

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For

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3-3

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GHRS Grating Spectral and Spectral Resolutions

range. The more the more intense

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wavelength

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as spectral

WAVELENGTH

SPECTRAL

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The

Digicon

range

to which

1; 2000

mation

pulses.

exposure

to

device

This information or after time.

system

can

re-align

for

the

motion

data

The

build

magnetic

shifted of

is

data

the

to

Space

the GHRS

detectors

go to the accu-

in SI C&DH

memory.

Then

passes

through

the SI C&DH

the inforformatter

and to the ground for analysis. If no communication with the STOCC is available, data are

it is sensi-

stored in recorders.

,'_ for Digicon

a photo-sensitive

from

mulators

detec-

tubes that count the pholight. Each Digicon has a

maximum 2. Each

goes

technique.

Digicon

1400

signal

Telescope.

the

Data 3.3.2.4

The

to an accumulating

immediately

a preset

deflection

event.

all diode

either

on parallel horizontal bands -- all first orders on one band, all second orders on another, and they

then

that records up over

order

it as one

window,

3-19

the

HST

on-board

science

tape

SIGNAL BOOST PREAMPLIFIER

INTERFACE WIRING _DtODE ARRAY DIGICON DIGICON WINDOW INCOMING

Figure

3.3.2.5

GHRS

tion control resides

Software.

software Control

and

The

GHRS

programs

for operational

Observation

time

Targeting

for the upcoming

• •

The

science

seven

selects

rotates and

sets

collection

--

make

the

HST

and

requests

field,

collects

that

exceed

servations

compensates

high-resolution of incoming

the

diode

data,

ob-

The

and checks

motion

for

the quality

data.

3-20

uses

onto

the

the

large

target

and

to repoint

target

into

light

targeting

relative

to a brighter in the

HST

maneuvers,

observer

also

target

acquisition

image

of

the

Planetary

Camera

aperture

to find

centers

object.

Then

aperture

the brighter

acquisition

for specific

small

measures

smaller

using

Different

and

the

the

procedure

aperture

is centered

as a guide.

under/overexposure

for vehicular lights,

stops

mode

adjustments

the

in the large

selected

and

place

The basic

small

has two baacquisition

necessary

the target target

detector

This to lock

aperture. location

target

acquisition.

aperture

ex-

a tar-

Spectrograph

modes:

Acquisition.

the

system.

controls

Modes

Resolution

data

science

observation. pinpoints

maneuver

control

High

sic operational

-- maps the field of view and sends to the STOCC if commanded.

magnetic limits,

pointing

SSM pointing

Mapping the data Data

for and

Operational

Target

setting,

Detector

but

unit (SI

includes

and aperture,

-- searches

get by sending to the

Handling

Digicon

3.3.3

phases:

to the correct

posure •

observa-

-- on command,

detector

carrousel

Data

GHRS

in the Scientific

software

set-up

the GHRS

The

GHRS

computer

C&DH).



3-20

is not in the unit itself,

in the NSSC-I

Instrument

The

LIGHT

its the by

object

mirrors

are

targets. can use two variations mode.

target

with

before the

One

first

takes

an

Wide

Field/

using the large

GHRS

target.

the

of the

Having

the

large

WF/PC

image

helps

the GHRS

target,

such as one

surrounded

similar

brightness,

which

on-board

The

target

other

GHRS

or precision

important,

the

Examples

would

than

knows centering

GHRS

can

of the target

is less

be pointed

be a repeat

object

will do.

Data

Acquisition.

lation

data

and

Accumulation

are

using

rapid

two

is the

seconds, can

minutes,

react

blocking and

Rapid

the target,

hours,

17-11 rr_

Wavelengttl Range

1050-3200 Ang.

time,

data

generally

After

each

Observations

The

GHRS

will

prove

celestial

mode.



Star



Studies

and

the

formations

as

3.3.5.1

software

and

of quasars

of

and dispersion medium

binaries and

the

other

extragalactic

has past.

a very

between time period

recorders, SI C&DH

Composition

and

Dis-

persion. The chemical composition of the atmosphere of stars, and of the surrounding matter,

earth

the observation

for

Atmospheric

short

is a question

long

GHRS

provide

may

data for atmospheric elements

in the patterns

by astronomers.

answers

cal

wavelength the GHRS.

50 msec

debated

tral

by studying

composition.

atmosphere

The specChemi-

have

unique

that can be identified

using

the indi-

cooling

the

a number

objects

can be stored

in on-board

in examining

radiation

objects:

information. this mode,

One

bypasses

useful

of ultraviolet

method

vidual block of data goes directly to the ground for analysis as the next time period begins. Data formation

resolution

Atmospheric composition Content of the interstellar

the interruption

provides

13 seconds.

2(X)O-100,000

for consistent Time can be

such

by pausing

it after

readout

observation and

or

to interruptions,

resuming

Resolution Magnitude Range

• • normal

observations interruptions.

to

accumu-

(direct)

used for gathering GHRS spectral The GHRS software accommodates lengthy sudden

ways

the GHRS:

readout

of data

monitoring quality and

2 arcsac 2 target, 0.25 arcsec 2 science

3.3.5

science mode

Apertures

with

target calibrations, or studying extended like galaxies, where any segment of the

acquire

J.C. Brandt, NASA]GSFC BallAerospace

blindly.

observation,

known objects

There

SPECTROGRAPH

Principal Investigator Contractor

a WF/PC

of the

HIGH-RESOLUTION

700 Ib (318 kg) 3x3x7 ft (0.gxO.9x2.2 m)

acquisi-

the location

Goddard High Resolution Spectrograph Specifications

Weight Dimensions

to map

This

3-4

GODDARD

the

less sky.

if the observer

target,

uses

aperture

2 field.

Spectrograph

confuse

variation

less time to process

but it covers

Goddard High Resolution Specifications

Table

the sky, up to a (10 arcsec)

Finally,

could

3.3.4

of

searches.

field of view of the large

image,

a difficult

by neighbors

target-acquisition

tion aid takes

locate

but the incomputer.

from

3-21

such red Zeta's

study giant

may star.

atmosphere

focus

on Zeta

Material

Aurigae,

is being

to an unseen

pulled

compan-

a

ion astronomers

believe

star.

will study

The

phere

GHRS

to analyze

may

be a younger,

the escaping

hot

3.3.5.3

atmos-

Star

ing binary

its chemistry.

GHRS. panion.

example

Io, orbiting canic

closer

to home,

the giant planet

eruptions

that,

Jupiter,

by

earth

they expel material Io's surface. The

breaks

and

apart

in Jupiter's

tating

magnetic

ring around ing

Io's

called

field

own

of gas,

elements, also

ring. with

This

examine

GHRS. the

volcanic

3.3.5.2 The

Content GHRS

determine

arms in spiral

can

the

study

high-pressure

Only

of high-resolution

from

For example,

Using

extended

periods,

arms

areas,

indicated

the

looking

with certain

sorption

lines,

chemical

makeup

of the absorption tures

of the

3-22 for lines.

of the galaxy in the spectrum

arms. with

dark

companion.

The

the

are among

than

their

on current

lates

that a quasar

clues

there

are

tion

and

Observa-

the most violent

spewing

out

enti-

energy

far

estimated

mass

can produce,

knowledge.

One

theory

center

massive

and

is a gigantic

specu-

black

hole

clusters, and matter nears

collisions

the

of a quasar

by

together

Extragalactic

universe,

explosions,

density

and of

gas the

nuclear

this

stellar

the extraordinary outpour3-24 is a dramatized depic-

center.

Some

quasars study

are close

ab-

can

the

quasar

center.

width

GHRS

can determine

tempera-

See

rendi-

observations

the

and

based

hole,

by the

called

arms.

to

wave-

calculate

lines will reveal

elements

a sample

absorbed

can

by a thick Epsilon

is an artistic

that is pulling stars, globular clouds into its vortex. As the

the spiral-

spectra,

astronomers

GHRS

piece

crunching produces ing of energy. Figure

spectra

of light

in the

greater

pressure,

ing gas will produce

the missing

the

intensity

through

because

the

may

Quasars

ties

for telltale

by the

hidden

possibilities.

Quasars

tions.

to

spectral

passing

missing

years GHRS

3.3.5.4

to be waves

the highest

spiral

gas. By analyzing

look

clouds

starlight

lengths

the

Medium.

interstellar

3-23

or a black

Io

would

Interstellar

the

can

is an art-

of the spectral lines (the greater the the more intense the spectral line).

In addition,

in birth,

of these

are thought

gases. over

through?

identify

galaxies

resolution

of dust and gas that still allows

tion of one

composition.

of compressed

or a protostar

shine

ring

of stars,

cloud

can

torus

not have

hole,

instrument

they

by its com-

could

Is it a pair

Figure

Epsichange

though

invisible be

two

as Epsilon or astronit. Is it translucent? A

and

3-21

eclipses. never

companion

composition have seen

spectra expelled

examine

their

is

stellar

is blocked

oxygen

Figure

of the

can

The dark

every

of almost

lines

of

com-

Epsilon

the eclipse,

light

and

gases the

or after star's

sodium, The

action.

ist's concept of what like if it were visible.

hot,

during, if the

ring of asteroids?

material

This extremely

the

a

most

spectral

same spectral omers would

to and surround-

orbiting

sulphur,

into

eclipses duration

should

star

has an invisible

companion

before,

for the

a yellow-white

also

than

Eclips-

targets

for an unusual

Aurigae's

panion.

ro-

Aurigae,

far longer

Ion

by par-

this material

ultraviolet

by

through

pulls

years,

are

Jupiter's

-- parallel

orbit.

has

observed

electrically

This

and Binaries. intriguing

magnitude,

27 years,

as far as 200 material then

magnetosphere.

Jupiter

a torus

ring

is charged

of

still has volstandards,

monumental: miles from ticles

the moon

offer

Epsilon

the third In another

Formation

stars

ejected

Figure

tion

absorption

the

from is likely

scientific

From the

to be

that

spectral

regular at what

quasar

instruments

ter simultaneously.

3-22

enough

ultraviolet

at the

observations,

the

velocity

center.

matter

This

in conjunction studying

the GHRS lines

the

is

observa-

with

other

quasar

cen-

Figure

3-21

Io's

Hot

SPECTRAL READING FOR OCCULTED LIGHT

Torus Ring

sures

ABSORPTION LINES

the

intensity

variation as short

I

and

light

from

HSP

opportunities

ultraviolet



Precisely



Test

I

of light,

to infrared.

and

any

measure

theories

This gives

the

to: the

about

for surrounding •

color

in that intensity observed over periods as 10 microseconds. It can measure

disks

Search

forvisible

mostly

by the

brightness

black

holes

by looking

of gas

pulsars, radio

of stars

until now observed

waves

emitted.

HIGHER TEMPERA'[ URE

3.4.1 Figure

3-22

Spectrum Absorption

with Liras

Physical

The High other

3.4

HIGH

SPEED

PHOTOMETER

The High tioned

Speed

parallel

Photometer to the

HST

(HSP), optical

rather HSE

also posiaxis,

mea-

3-23

Photometer,

instruments,

chanical ter,

Speed

Description

for

design example, than

is relatively and

compared

to the

simple

in me-

has no moving

is chosen

by moving

a filter

parts.

by moving wheel

A filthe

within

ST the

Figure The HSP

is the same

3-23

Epsilon

size as the other

Aurigae

(right) and Mystery

axial Sis, 3

Incoming

× 3 x 7 ft (0.9 × 0.9 x 2.2 m), but it weighs only 600 lb (273 kg). Its main structure is a box beam run-

through

ning

sembly

the length

of the

tronics, thermal, tems are mounted the

instrument

system,

instrument.

and communication on bulkheads. The is

the

optical

located

in the

forward

See

Figure

3-25

structure.

Power,

subsysheart of

detector end for

of the the

starlight

plate

isolate

coming

light.

sub-

portion

of

HSP

apertures,

overall

the

The the

aperture

ground

spectral

cal

Optical

detector

holes

Detector

system

in the forward

of four

filter/aperture

Subsystem.

consists bulkhead,

in-

directs

a

light; the medium

of

three

in diameter.

one

The

aperture

of the

back-

is most

accu-

is for locating

a tar-

The opti-

of four

entrance

directly

assemblies.

in the

much

rate; and the large aperture get (see Figure 3-27). 3.4.1.1

ranges

through

removes

as-

filters,

assembly

0.4, 1.0, or 10 arcsec

smallest

Each

13 colored

selected

beam

passes

and falls onto

assembly.

contains

certain

target

holes

filter/aperture

filter

which

configuration.

from

one of the entrance

a particular

elec-

Companion

The

in front

Four

light

assembly

light

which

passes and

through

reflects

sharpen

a

off the

the light. Then

filter/aperture

ellipsoid

mirrors,

the light enters

an

dissectors, one photomultiplier detector, and three off-axis ellipsoid relay mirrors complete

image dissector tube (IDT). Two IDTs are sensitive to light from 1600 A, to 6500 A, (ultraviolet

the optics.

through

optical

See Figure

3-26 for the layout

of the

system.

ultraviolet

3-24

visible),

and

wavelengths

two

are

from

sensitive 1200

to only

-- 3000/_.

Figure

Electrons

emitted

focused

3-24

which

Collisions

by the IDT photocathode

by a magnetic

the 12-stage

Stellar

field

amplifies

the

sky background,

section

electron

The

to

violet

filters

(3M

Polacoat),

ble

and

light

red-sensitive

measures to 7500

photomultiplier

a clear

frared

light

into the

light dissector same

The

object

HSP

ments.

tube.

PMT

tube

light

splitter

and

UV

to a certain

diverts light

light from

polarimetric electric plane).

the

3.4.1.2

an

tion

the

dissector. not

as magnetic

field

enters

from

turbulence dims

General

be

the

accessi-

fields

and

dust.

Space

should

ground

(which

be

because

causes

stars

to

is eliminated.

Operation.

involves

how many measured

HSP

the

starlight) liSP

HSP

positioning the measurements.

The

opera-

an

object,

selecting

bands of wavelengths and for how long, and Telescope

to take

those

of Once

vibrations

Light

with

than

and

of the

deciding should

measureintensity

greater

"twinkle"

in-

into

accuracy

atmospheric

simultaneously.

measures

(whose

much

(PMT)

range, close light passes

Red and blue

can make

Polarimetry

confined

a beam

can be studied

also

polarized are

filter,

material

image

interstellar

ultra-

can be measured.

light in the near infrared ,_. After the incoming

through

an

phenomena

such

through

of four

polarized

onto

can study

reflected

one

with

then

to photometry,

righO

through

overlaid

Photometric A

(lower

assembly

Polarimetry

mag-

IDT amplify electrons of the photocathode. The

for example,

Center

filter

of the IDT,

signal.

Quasar

are

into the entrance

photomultiplier

netic field lets the emitted from any area

Above

a

load

3-25

the astronomer Operations

selects Control

an object, Center

the Pay(POCC)

HIGH SPEED PHOTOMETER - ELECTRONICS

BOXES

DETECTOR ELECTRONICS SYSTEM CONTROLLER POWER CONVERTER REMOTE INTERFACE EXPANDER UNIT SIGNAL DISTRIBUTION

REGISTRATION

ASSEMBLIES

AND DISTRIBUTION UNITS

UNIT

f

SUBSYSTEM

ELECTRONICS

BASEPLATE

FITTING 'C' -_

TERIOR

BULKHEADS

REGISTRATION _,_ Fn'TING 'A' --4"I"-

LIGHT ENTRANCE

IMAGE DISSECTOR PHOTOMULTIPLIER PREAMPLIFIERS

HOLES J

TUBES TUBE

HIGH VOLTAGE POWER SUPPLIES OFF-AXIS ELLIPSOIDAL MIRRORS FILTER/APERTURE TUBES

Figure

3-25

Overall

HSP

Configuration

IDT-POLA RIMET RY ST oPTICAL

AXIS

- -- ---"-'1"--"_--

---

-- --

_/_ _3-'2"_ -_',_- - -_ - -__-_ _-_:;.z__-.._-'_Z_ ,NOOM,,_G-----_7,..,__--.'-.... __\----T "W__--t.T--_ __.,.4 ---OFF-AX,S PHoTONs /

.....

_

_, _

ENCLOSURE

_/"

y

k,_} _X'-

_'-

3-26

-

3 IDTs- PHO FOMERY

PMT-OCCULTATIONS

ELLIPSOIDS

ments "__

_

'"'"-"_/

/RECEPTACLE

cove./

light passes

through

into

the

dissector,

image

and

system,

LIGHT INCOMIN_G



0

*



o

-_o.,,9

0



0





o



0



0





O



O

0



0





O



O



O



O

10 SEC APERTURE

to the ground for later

number

each

exposure,

rate

APERTURE

which

and

amplifies

the

electronic

data

SI C&DH

or stores

depend

sends

the information

and

upon

example,

the

a very

length

of

brightness star

exposure

while

an hour

the

a bright

a one-second

measurement,

require

back-

transmission.

For

only

The

of exposures,

target.

and

HST.

the filter/aperture

to the SI C&DH.

The

star the

it, via the HSP

on tape

need

-,,,,_ o ":-'04,_E(_

passes

the data

the

o

0

0

primary moving

The

cove. _

example,

sky) without

signal

APE,TU,Ep,ATE liL__g _//._,_ __

FILTERS (IN 2

(for

ground

,TUBE

of might

for an accufaint

star

might

exposure.

COLUMNS)

0

O



3.4.2

Operational

Modes



The

High

Speed

Photometer

has

several

10 SEC APERTURE

Figure

places

3-27

the

C&DH

Filter/Aperture Tube, Exploded Configuration

software

computer

usually

when

until

the HST

general direction observation. Then mands and uses to find and lock the

commands the

into

the

Targeting depending

uses upon

make

SI

time,

mers

can

use

after another reads the com-

point

the

target,

onto

software stars.

the pointing control subsystem onto the guide stars, then onto

Once

target. light passes

through

so that the HSP of movement

can center needed

first filter/aperture the

NSSC-I.

pointing moves

The

control until

the

10-arcsec

the target.

to place

that

combination

The light

angle

the

is calculated

coordinates

are

subsystem,

and

the light falls onto

passed the

by

Star-sky,

telescope

the correct

• The

spacecraft

ments aperture

to

place

may the

combinations.

repeat light

the in

small

adjust-

different

filter/

and

filters

study

However,

have two pairs of 0.4 and 1.0 arcsec which can be used for simultaneous

most



apertures, measure-

3-27

observations

the

Astronoto help

with

the

pin-

targeting

in a crowded

field

by the correct

can observe

which

which

uses

uses several the star's

of

filter

and measure

one

to study

rapid

another

IDT

the

sky at the

Polarimetry, filter.

which

aperture/filter

apertures

on one

brightness

of the background

od of time (minimum Two-IDT, which uses (usually

light from

aperture.

is acquired

to capture

brightness

filter.

aperture, chosen, to

ways:



filter

reposition

or interact

the HSP

Single-color, combination.

to the

target-acquisition

data

earlier

target



on the

that

to find the target

it in several

aperture

a

the largest HSP the image dissector

the correct

and aperture, The

plus

calculations

in the

is pointing

of the target the software

modes,

target

appropriate

already

observing mode.

and

sky over

is 10 millisec). one IDT for star changes

with the same same

the

a peristudy

in brightness) filter

type to

time.

uses the special

polarized

3.4.3

High

Speed

Photometer

Specifications

pulsars,

and

their pulsations

thousandths Table

3-5

High Speed Specifications HIGH-SPEED

PHOTOMETER

Pnncipal Investigator Contractor

R. Bless, U. of Wisconsin U. of Wisconsin

Apertures Resolution

0.4,1 0,10.0 arcsec 2 Filter-defined

Magnitude Range

< 24 m v

Wavelength Range

1200-7500 Ang.

ture tivity

and

can disclose the High

stars requiring

inherent

theories currently

will provide light-intensity determine stellar distances pulsars

and

serve

black

starlight

spheres

holes.

filtering

through

(occultation

sensi-

photometer

HSP

than

the

sun,

a beam

HSP

may

sars

atmo-

have

been

of the HSP.

HSP's

sensitivity

capture

these

The

can apply

luminosity

of light

stars because the

information

formulas

and magnitude

coming it has

a

faint-object is known,

to determine

of the target

the

astronomers can use, along with temperature color and other data, to calculate distances those stars.

or to

3.4.4.2

20

objects than

Search

for

astronomers emitting steadily.

Pulsars. have

radio These

waves objects

a cosmic

solve

some

Recently

light-

is shown

of the

mystery

a few visible

within

the

Astronomers

pul-

magnitude

hope

to use the

faint visible

In addition,

light to

the photome-

For been

nearly

HSP

of the light pulses

physical can

properties

information

light-varying, and Seyfert

high-energy galaxies.

objects, The

spiral-armed

galaxies

can

extrapolate

variations 3.4.4.3

that

vary

the

measured Occultation

planets

on

other

like quasars latter are in brightness.

may be caused by frequent galaxy's center. Astronomers core

diameter

by the

from

time

The

HSP

HSP.

Observations.

will record starlight occulted gases surrounding comet tails, System

to help de-

of pulsars.

provide

Seyfert pulsations explosions at the

star. By

observing faint and bright stars, the High Speed Photometer can contribute magnitude data that

years

rapidly,

ter can record light pulses as frequently as every 10 microseconds. The HSP also can record the

even

scientists

of a pulsar

to UV and

can measure

this

on

times

spin

like

pulses.

from

Once

stars

rendering

located

range

HSP

instruments.

as

based

A thousand

of energy

help

and color

than

models

neutron

pulsars.

the

range

created

hotter

termine

dynamic

down

of a dying star, perhaps 20 kiloThese stars are so dense that

intensity

greater

pattern, irregular observed

are slowing

exists only as neutrons.

surrounding

also will ob-

planetary

intensity

their have have

about the origin of pulsars. One model, in favor, is the neutron star, the small

3.4.4.1 Measuring Stellar Magnitudes. Astronomers must know how intensely a star burns before they can measure its distance. The the

in

matter

The

also

observations).

the brightest

few

Photometer

information to help and to search for

The

every

few seconds.

energy.

have

house. An artist's in Figure 3-28.

the tempera-

the ultraviolet

in the HSP. The

their

collapsed core meters across.

Speed

regular

gradually

Astrophysicists

spraying

of starlight

will observe

pulsars

they dissipate

Observations

of a star,

are

to every

some, called bursters, of pulses. Astronomers

that most

600 Ib (273 kg) 3x3x7 ft (0.gxOgx2.2 m)

The color

pulsars

though patterns

Weight Dimensions

3.4.4

Most

Photometer

vary from

of a second

by atmospheric stars, and Solar

and asteroids.

discovering

in pulses

rather

Two examples

now

called

can observe

are

3-28

are starlight

appropriate filtered

here.

The

HSP

by the atmosphere

Figure of Titan,

one

wavelengths astronomers

If

through field ods

intensity

is blocking

brightness

the properties

varies the

in starlight,

of time,

Uranus.

Some

light

by the gases,

Since

variations

the

light. the

Pulsar

3.5

The

passes

within

that

WIDE

most

is the

Wide

used

It can produce

over

peri-

tometric,

nine

around

short

rings

around

rings

WF/PC

with

wider ment

Neptune,

3-29

FIELD/PLANETARY

versatile

Astronomers

photographed

upon

the Voyager

of that

light

something

observed

to discover Voyager

as

Rotating

astronomers hope to expand discovery (see Figure 3-29).

and

atmosphere.

a field of matter,

variation

Visible

by the way the light dims as it passes the

light

moons.

can calculate

atmosphere through

of Saturn's

will be absorbed

3-28

and

of the scientific

Field/Planetary images

will obtain

Camera

instruments (WF/PC).

and spectrographic,

polarimetric

and grander to date.

CAMERA

pictures scale

measurements. of the universe than

any

other

phoThe on a instru-

Figure The WF/PC camera

has two camera

(WFC),

and

This is like having on the wide

camera. field

still would

(for need

the

WFC HST;

down

100 pictures

these

investigate,

two camera among

age,

the location

the

atmospheric

modes,

many and

to

shape

patterns

but it has 2.

how

of black of

Solar

and

FOC

cameras

with

four

will broaden

the scope

data.

The

will take

WF/PC

different

of the wider

func-

HST

visual

photographs

nearby

objects,

too

bright

for the

The

FOC

distance

such

as planets,

that

are

FOC.

a capability

is the

with sharper resolution. However, maximum field of view is (22 arcsec)

may

galaxies

holes,

two

tions

graph

angular objects

the WF/PC

things,

of WF/PC

of faint objects, without as much detail as the Faint Object Camera. The PC mode can photo-

but with limited

that are apart by only 0.01 arcsec, smaller field of view at (66 arcsec)

With

Having

It uses a focal ratio of of view of (2.7 armin) 2

to 28my,

Comparison

lens

camera

angular resolution. The PC has better resolution than the WFC, separating

Neptune

3.5.1

a relatively

wide-field

about

Around

(PC).

and a zoom

exposes the

to take

Rings

wide-field

or closeup

a wide-angle

photograph the moon). f/12.9 with a large field for magnitudes

modes:

planetary

The

3-29

and

System

to the

WF/PC

FOC,

for

within

a cluster

capture

planets.

3-30

(2.7 arcmin)

example,

can

of galaxies

the entire

cluster.

2 field

concentrate while

same,

but

the FOC's 2 compared of view. on

the WF/PC

The detail can

3.5.2

Physical

Description

The Wide Field/Planetary Camera 1.7 ft (1 x 1.5 x 0.5 m) in size, with radiator

that

unit weighs

is 2.6 x 7 fl (.8 x 2.2 m). The 595 Ib (270

the California the camera tory

kg). J. A. Westphal

Institute and

built

is 3.3 x 5 x an exterior

of Technology

NAS_/s

Jet

camera

configurations,

with

system; WF/PC

and a processing and send data

system to operate the to the Scientific Instru-

ment

total

Control

3-30 for WF/PC.

and

& Data

the

a cooling

Handling

radiator

unit. See Figure

overall

configuration

System.

The

of

the

system

for

designed

Propulsion

Labora-

3.5.2.1

it.

Optics

the WF/PC

consists

in the direct

optical

of a pickoff

mirror

line of the telescope

an

entrance

PC "pickoff"

ror to split the light; and fold and relay optics place the lights onto the CCDs.

pathway, into the instrument A, and between The eight

in the

middle

of the

filters,

focal

reflects the center of the light beam camera. The spectral range of this is the widest, from 1150 A to 11,000 the resolution objects

camera

will allow

it to distinguish

only 0.1 arcsec

is composed

charge-coupled

apart.

of an optics

detectors

(CCD)

gratings,

The

pickoff

light

path

the

with shutter;

light path;

The WF/PC is perpendicular to the HST optical axis, in front of the focal plane structure. A WF/ mirror,

aperture

inserted with

a pyramid

mir-

and polarizers;

mirror

is centered

of the telescope.

central

a carrousel

section

of the

diagonally The

mirror

beam

at a 90-degree

in two

length

of

exposure,

from

approximately

PIPES HEAD :)NICS -V3

RELAY

OPTICS

LIGHT

-_

EPOXY)

APERTURE MECHANISM

! '-" FOLD

+V3

MIRRORS

FILTERS t

-V2

FILTER CAROUSEL (50 FILTERS)

Figure

3-30

The

in the deflects

angle into the entrance aperture of the WF/PC. The shutter behind the aperture controls the

system;

HEAT

OPTICAL (GRAPHITE

to

Overall

3-31

WF/PC

Configuration

SEAL

0.1 second

to over

27 hours.

A typical

time is expected to be 45 minutes, half an orbit around earth.

exposure

parts, along CCDs.

or roughly

The

light

reflects

up to fold The

light

which

passes

contains

ducing

through

48 filters,

undispersed

diffraction WF/PC

lights

gratings,

and

can place

one

into the light path ple,

the

measure sure.

WF/PC light

The

carrousel,

for

lenses

three

See Figure

The

cal system.

of the

filters

or several take

assembly,

the

with

the WF/PC

3.5.2.2

For exam-

a photograph

during

array

expo-

mirrors,

or PC mode

is implemented

amid

mirror

to one

The

pyramid

splits

of two the

the pyr-

45-degree

angles.

light

beam

into

down

which

As the

from

the the

four

system.

incoming CCD.

These CCD.

of the basic

Detectors. is a silicon

are position

photons

pixel

photons

Each

detectors, the

charge striking

pattern later.

then

passes 3-32

will strike

._("_._

_::A:L

,

::i!T

! L_/7_

/

/

/--

/ /

of the light The charge through

illustrates the

pixels

f,_'_

PYRAMID

/ f-RADIATION

/f'_'-

/

..........

_,,,,

p

,_/

/-PICK-OFF

l Y'_i'-'ii_ii_''"''"':::::'_-!!!!!i_)ii_

RITCHEY-CHRETIEN REPEATER

_

--_

/

/

/

,/

PLANO _ RELAY MIRROR

/" /

,' OTA

,/

OPTICAL AXIS

,/ /

,,

/

f"

t/



Ie

s*'

/

/'

/



/ / / /

Figure

3-31

Wide

FieldPlanetary

3-32

Camera

Optics

Design

800 array,

proporit. This

f- SENSOR / ELECTRONICS //PLATFORM r- EXTERNAL / RADIATOR /

opti-

chip with an

bombard

Figure

back

the pyramid

mirrors. the selected

the intensity each

electronics

set of

mirror

past

the light is reconstructed

signal

the WFC

by moving

then

each pixel records an electrical tional to the number of photons

versatile

to use either

the pyramid

detector

ofpixels,

when the decision

to a specific

Charge-Coupled

will reproduce At this point

goes

3-31 for a diagram

on a side.

its overlapping

the most

from

charge-coupled

and

same

that

mirror and onto re-imaging focus the beam, finally, onto

pro-

polarizers.

targeting,

for dual functions. can

filter

filter clear

three

intensity

capability, makes of all instruments.

a four

a path

the how of

The

CCDs

such

a wide

are

powerful

spectral

nal, especially

range

for faint noise

from

interference.

The

spectral

phor

because

each

that converts In addition,

the CCD

is toward

trum.

The

heat

and

great

natural

(8002) from each when processed.

CCD,

3.5.3

of

view

and

image

either

WF/PC's

Within the

each

beam

Ii

/

!

Wide

Y

8O0

3-32

is minimized

WF/PC in each

keeps degrees

Imaging CCD

the CCD Celsius.

because

the

temperature

at a

a special

The

sys-

unit bathes

regularly

to short

cooling

Processing

the CCDs

to increase

is per-

system

and

the the

System.

CCD

the

This

Camera use

both

spectroscopy

for

spectra. specific

The wave-

photometry,

as well

as for filter

polari-

in the 2500-

to -8000

A, spectral

range.

Wide Field/Planetary Specifications

3-6

Camera

Wide Field/Planetary Specifications

with

WF/PC

has a

camera operaSI C&DH unit.

sets shutter exposure time, filter combinations, rotates

the

to select

a specific

mode

ultraviolet filters

WIDE FIELD/PLANETARY

The

basic

light

bombard-

photometric.

to capture also

of the

that

of the

the

basic

the WF/PC

detectors,

makes

and

The Because

intensity

Field/Planetary can

photometry,

since

target.

to study

Camera

the CCD

The microprocessor selects the required mirror

is imaging,

yields

are sever-

select

include

of the

of the

also

there can

metry

Table

wavelengths.

microprocessor that controls tions and transfers data to the

pyramid

of

length

3.5.4

tem consists of pipes that conduct heat from the CCDs to a radiator on the surface of the SSM.

3.5.2.3

acquisition

operation,

mode

uses a grating camera

sensitivity

field

photopolarimetry.

an image

light-producing

light

as

of view to capture

modes

and

ing photons.

ultraviolet

a separate

astronomers

These

construction

In addition,

operates or a planetary

guidance

field

camera

target.

records

8004

-95

has

Target

the HST

that

operational

INCOMING IMAGE

nominal

Camera

Each

generous

spectroscopy,

system

coming

target.

I::::::::::::::::::1

cooling

signals

a wide-field

resolution. using

al modes

Heat

the

Modes

camera.

formed

J

Figure

out

Field/Planetary

(cioseup)

640,000

to a single

Wide

two cameras,

end of the spec-

add

Operational

The

to visible

of signals,

reads

is

sensitivity

the infrared

path, and the CCDs.

by

with a phos-

photons

number

the sig-

accepted

chip is coated

optic from

electronic

energy

the

cover

is uncluttered

ultraviolet

photons.

they

and because

objects,

background broad

because

Weight Dimensions

595 Ib (270 kg)

Principal Investk3ator Contractor

J.A. WestphaJ, CIT

Optical Modes Field of View

camera

3-33

CAMERA

Camera - 3.3x5x1.7 ft (lxl .3x0.5 m Radiator - 2.6x7 ft (0.8x2.2 m)2 Jet Propulsion Laboratory f/12.9 0NF), t/30 (P) 160, 66 amsec _

Magnitude Range

9-28 my

Wavelength Range

1150-11,000 Ang

3.5.5

Observations

light-blocking ness

The Wide Field/Planetary Camera busiest scientific instrument on Space

Telescope.

With its variety

the WF/PC can perform observing a single object. focus

on

an

will be the the Hubble

extended

galaxy

and

take

picture of the galaxy, then concenthe galaxy nucleus to measure light

intensity

and

photographic

closeups

its "sun"

wobble

can chart

this wobble

sufficient

tary

the

Martian

Mariner

tains

verse

expansion

nova, comet, tant searches planets spheric galaxy amples

and are

in other storms,

star formation. below.

"hide"

behind

tational

pull.

become

a black

diameter,

the

hole,

often

the

atmosphere and other

of the

superdense

the black

of the hole,

until,

search

black

for

holes.

rendition

See

of

swirling Figure

a blue

to

disks 3-33

for

giant-black

binary

Field/Planetary instruments The

Camera

Systems. and

other

will study stars looking

WF/PC

pyramid

mirror

The

Wide

have

disappeared

by now,

affect

Collide.

The

process

When

Galaxies being

pattern,

A prime

When

this

happens,

sweep

through

tended

lobes

gases.

WF/PC

observation

evidence

and

huge

is when

in Figure

3-34.

shock arms

waves and

compressing

If a critical

gases

resolution

from

of this col-

tremendous

of the galaxies, the

of the

of gases

spiral

and

into

conception

capa-

a three-year

of a specific

of a star being

is

nuclear

spectrographic over

ex-

density

explode

could,

of

scientif-

believe,

the gaseous

the

gravitational

example

illustrated

The

periodically

the

astronomers

collide,

winds.

by several

with

ignition

clouds.

high

studied

climaxes

and nuclear

to the

after

they

galaxies ing gas

3-34

For

the Viking

how

more

3-35 for an artist's a

evidence. near

patterns

duce

scientific

dramatic

appearing

precisely

The

for planets. has

wind-

the wind

periodic in Other

spacecrafts

can study

bility Planets

lander

from

study of Martian

more

reached, coalesced life as a star.

system. 3.5.5.2

Pictures

WF/PC

compacting

of

artistic

Object

this plane-

of exposure

two galaxies

of the WF/PC

an

Faint

of years

lapsing

of

hole

should

interstellar

star.

as evidence

the

millions

collapse

in

a swirling

at the edge

to gen-

Storms.

Intense

ic instruments,

is part of a

create

time.

star formation,

core

companion

The

years

See

Viking

the craters

3.5.5.4

also may pull gases

elements

9 and

to calculate surface.

gravi-

the hole, all light disappears because overwhelming gravitational pull. The will

lander

Black

collapses

over

example,

ex-

only a few miles

the hole

The gases disk around

star

into it. If a black hole

star system,

from

Hole.

overwhelming

a dying

gravity

pulls all matter binary

a Black their

When

Those

path.

over

plan to attack

Dust

has not produced

super-

star systems, Martian atmoand the connection between

Photographing

holes

star,

planet studies. Some imporfor evidence of black holes,

collisions and are discussed

3.5.5.1

to specific

force

storms has astronomers and geologists puzzled because the erosion predicted by these studies

for the WF/PC range distance scales and uni-

theories

the size

clearly demonstrated that Martian winds sculpt the landscape, eroding the craters and moun-

observing. Specific observations from tests of cosmic

A planet

search.

3.5.5.3

center. In addition, the WF/PC can perform measurements while other instruments are

be plotted

in its orbital

evidence.

for a different

can

gravitational

enough

WF/PC Camera

of the

background.

can exert

of the bright-

path

to make erate

a

some

so its orbital

the starry

of Jupiter

while it can

wide-field trate on

take

against

of capabilities,

several tasks For example,

spot to mute

of a star

born.

target, See

proFigure

of this birth:

approach, then collide (top), until it ignites (bottom).

two

compress-

Figure

3-33

Black

Hole

in Binary 3.6

System

ASTROMETRY SENSORS)

When

two of the

(FINE

fine

GUIDANCE

guidance

sensors

(FGSs)

are locked on guide stars to provide pointing information for the HST, the third FGS can serve as an scientific instrument to measure the position

of stars

in relation

called astrometry, determine stellar

The They

Palomat

Figure

3-34

Two Spiral Colliding

Observatory

Photograph.

are

located

at right

Space

Telescope "pick-off"

stars.

fabricated in the

angles and mirrors

by Perkin-Elmer.

focal

plane

to the optical 90

degrees

to deflect

structure, path

of the

apart.

They

the incoming

light into their apertures. (See 2.3, Chapter a more detailed description of the FGSs.)

3-35

This is

and it will help astronomers masses and distances.

were

placed have

Galaxies

sensors

to other

2 for

Figure 3.6.1

Fine Guidance Table

3-7

Sensor

3-35

Time-Lapsed

Specifications

Fine Guidance

Star Birth

3.6.2

Operational

Once

Sensors

the

sensors

Specifications

sensor FINE GUIDANCE

485 Ib (220 kg)

Dimensions Contractor

1.6x3.3x5,4 ft (05xlx1.6 Perkin-Elmer Corp.

Astrometric Modes Precision Measurement

Stationary & Moving Target. Scan 0,002 arcsec 2 10 stars in 10 min

sure

m)

lock onto guide

stars

metric

Access: 60 arcmin 2 Detect: 5 arcsec 2

Magnitude Range Wavelength Range

target-acquisition

can perform

There

Speed Field of View

for Astrometry

stars,

fine

guidance

the third

guidance

astrometric

operations

on

targets within the field of view set by the guidestar positions. The sensor should be able to mea-

SENSORS

Weight

two

Modes

as faint

are

three

modes

position

for

mode,

astrotrans-

fer-function mode, and moving-target Position mode allows the astrometric

mode. FGS to

calculate

relative

be

the

measured

keeps

3-36

operational

observations:

to the guide

4-18.5 my 4670-7000 Ang.

as 18 my.

the

angular stars.

within pointing

position

Generally,

of a star

up to 10 stars

a 20-minute stability

of

span, the

will

which

guide-star

FGSs within 0.04 arcsec.

the

required

accuracy

3.6.4

of

Astrometric

Astronomers charting The transfer-function eter

of the

analysis

er

stellar

target.

either

System

planets, than

of the

latter

a

include

stars

visually

clos-

and

targets

sur-

arcsec,

by nebulous

direct

or by scanning

double

0.1

the diam-

through

object

Examples

together

rounded

measures

target,

of a single-point

diffuse Solar

mode

Observations

measure

its location

at different

times,

The

earth's

orbit

ent)

location

the distance

to a star

on two sightings nominally changes

from

six months

apart.

the perceived

of the nearby

star, and

(appar-

the parallax

angle between the two locations can lead to a estimate of the distance to the star. Stars are so distant,

gases.

of course,

quite

small,

that

requiring

the

parallax

a precise

angle

field

ally

measurements

separated

produce

by

of binary

more

than

measurements

ing to information gravity

in the

0.1

of stellar on the

stars

visu-

arcsec

can

masses,

importance

evolution

of star

tances stars

in our

objects,

called

because mode

measures

moving target relative to other not possible to precisely lock target.

An

example

angular

position

would

of a moon

a

rapidly-

targets when it is onto the moving be

measuring

relative

Each

FGS

Filter

measurement and wheel and

of stars

to classify faint-star

increasing ferent from

and a

contrast colors,

star

or

being

observed.

13my)

colored color

between reducing

related

to

important magnitudes

astrometry;

those

of nearby

faint

regular measure

for

nova the

by relating

to apparent shines), then

magnitude calculating

to

a

nearby

more

Cepheid

astronomers

can

Cepheids

with

faint

Cepheids

vis-

Telescope. Using this informawill calculate the distance to In

Cepheids

the

neighborhood

of

will be supergiant

and

stars. Astronomers distance to these

index,

from

close

of dif-

and supergiants are bright than Cepheids, they are excellent "distance standards" for measur-

background

light

ing greater

nebulosity.

3-37

Cepheid

distances.

comparisons.

can accurately brighter objects

(chemical) stars

the

can

to a Cepheid

between

Cepheids.

fainter

is

(absolute

Astronomers

because

and

reg-

pulsations

luminosity

distance

distances

notable

or pulse,

these

Cepheid.

periods the star

compare

the

of

the distance

becomes

are

and contract,

intrinsic

of the

ible to the Space tion, astronomers

The

used

the

the

acquisition

filters

nearby

that are consuch class of

variables,

frequency

Knowing

known

brightness

for observation

two

target's

for astrometric

for guide-star

Cepheid

the pulsation (how brightly the distance.

to its parent

different

than

filter

stars;

estimating

stars

filter

(greater

neutral-density bright

the

has a clear

with

The

determine

the

Wheel

FGS also has a filter wheel

beyond

stars, however, indicators. One

they expand

ularly.

magnitude)

planet.

3.6.3

method

galaxy.

There are certain sidered distance

planetary

systems.

Moving-target

parallax

of dis-

lead-

of stellar

and

by the

is

of view to

calculate the angle. Even with the precision the FGS, astronomers cannot measure Astrometric

by

earth

Since

novae

Section HUBBLE The

Hubble

Space

SPACE

Telescope,

once

TELESCOPE

deployed

by

4 MISSION Flight

operations

the Space Shuttle, will have a mission extending at least 15 years, based on orbital maintenance.

through Telescope

The

launched

HST

program

sion phases:

has

launch

three

and

operational

deployment

mis-

operations,

supported by the Space q'i'ansportation mission operations once in orbit, which the verification vations;

testing

and

Space

first

Hubble

Space

launch

of the

scope.

Chapter

tions

responsible

gram:

Marshall

project

Company

prime

strument developed

Center,

&

Corp.

and

a team

for of in-

development teams that designed the five scientific instruments.

arm will place

the

built

Systems

internal

Support

Telescope

and

Assembly

of the

built

of mirrors

Space

and optics,

Telescope

the

and sup-

Kennedy

Space

coordinated Telescope (STOCC) specific

before

Mission

crews

for its flight

cargo

bay.

mission flight Operations

its shipment

prepared

the

Space

the Shuttle

in-space

maneuvers may

remote

Center

and

Space

Tele-

manipulating

runs Shuttle the

posi-

the deployment will release the

HST will begin

oper-

operation

spacecraft tem and

it into

of

the

the in-flight

Space

testing

Telescope.

The

will undergo up to six months of sysinstrument testing and calibration to

determine

the

to 15 years.

Once

perform

concern

HST's

ability

to function

operational,

observations

for up

the telescope

selected

and

will

supervised

by the Space Telescope Science Institute. The Payload Operations Control Center will handle commands

tus-signal the latter

processing, and with the Institute.

the Institute Support

and

and

operations,

sta-

mission scheduling, The liaison between

the POCC

will be the Science

Center'.

During its life, the Space Telescope with certain defined characteristics, much

time

it spends

orbit,

or maneuvering Telescope,

in the earth's and

will operate such as how shadow

viewing

for example,

within 50 degrees of the sun when unless the sun is behind the earth, the HST.

each

constraints. cannot

point

maneuvering as viewed by

Center

plans with the Space Control Center

and trained

vehicular activities that the Shuttle lifts off.

the

under

and loaded

Johnson

launch

the HST into orbital

and

operations

The Space

prelaunch

Telescope

Shuttle

tested

for durability

liftoff and orbit conditions, to Kennedy Space Center.

the

some

Perkin-Elmer

instruments,

completed

the

and

structure,

structures, as well as the three fine guidsensors. Then Lockheed assembled all the

components,

At

outer

Module,

equipment.

Optical port ance

the spacecraft's

for the

the Shuttle's

the STOCC Finally, the

spacecraft Lockheed

Space

required

system

and

for overall Missiles

Perkin-Elmer

responsibility;

the orbit Then

from

the Tele-

of the HST pro-

Lockheed

and

contract

Space

the organiza-

for that phase Flight

with

the

5 lists completely Space

the

Kennedy

scope.

tion as sequence.

the period

which places the Space The Space Shuttle will be

of the

concludes

carrying

from

Space Telescope, ating on its own.

development

Telescope, Shuttle

over

in orbit.

phase,

management;

Space

operations

lifetime

program

obser-

cover

deployment, into orbit.

establish

System; includes

the scientific

maintenance

Telescope's

The

and

DESCRIPTION

astronauts

for

and

extra-

be required

once

4-1

In the

maintenance

and

the Shuttle can bring up ment on a maintenance Space Telescope it back to earth

refurbishment

phase,

replacement equipmission, move the

to a higher orbit, or even for major overhaul.

bring

4.1

LAUNCH

The

launch

place

AND

through

the Hubble

checking sections

DEPLOYMENT deployment

Space

out the HST systems. discuss the launch and

the Hubble

Space

Telescope

planned contingencies could arise.

4.1.1

Launch

Prior

to launch

with the

flight

deck,

after

The following deployment of

in detail,

for

from

Hubble

switch

will

in orbit,

including

emergencies

that

and Predeployment

cargo bay, the communication dard

operation

Telescope

Kennedy

Space

Space

Telescope

Center,

in the Shuttle

Orbiter will provide power and for the HST. The Orbiter stan-

panel,

located

will control

in the

power

Orbiter

aft

to the HST

until

the spacecraft is deployed. Essential power the HST will come from the Orbiter through external connects

power line called an umbilical, to the HST aft bulkhead.

fixed-head

star tracker

prevent antennas

contamination and solar

addition, rate

the

sensing

At

launch,

330

nmi.

inclined

will be closed

to

during launch, and arrays will be stowed.

multiple-access

the

Shuttle

receivers

km),

will

Center's

the In

and

from

TX, will confirm lifting

to an

or

Mission

the Shuttle

lift

plus

at 28.5 degrees

Houston,

which The

the

unit will be powered.

(607

son Space shows

shutters

to an

orbit

minus

of

5 miles,

the equator.

John-

Control

Center,

the orbit.

Figure

off the Kennedy

Figure

4-1

launch

Predeployment

After the

establishing cargo

space. start

bay

up the

The

crew

and

expose

two

hours

later

telemetry

device

Operation

the

doors

interrogator

nication

Checkout an orbit

Roughly

payload

HST.

main hours

that

Control Orbiter

systems links

the

Center will send

the

and

(PI). The

will open HST

the

crew

the

Shuttle

to depressurize. HST thermostatic

keep

the

internal

vival

temperature

components

levels

above

as temperatures

surdrop

to will

Orbiter

For the

rest

will turn

of the

on the

Space

Telescope and

electronics

assembly,

deployment

control

the HST

4-2

interface

first

data

unit/science

to the

at least four system com-

in space.

data

power

Off

The STOCC will turn heaters so they can

HST

PI is the commu-

(STOCC)

Lifting

power buses after waiting for the HST communication

ponents on the

pad. 4.1.2

4-1

in

units, data

flight

day,

the

management tape

formatter, rate

STOCC

subsystem,

recorders,

control

pointing/safemode gyro

electronics.

assemblies, The

and

STOCC

will

monitor,

computer systems data

via

telemetry,

memory undergoing

and

testing.

go to the

PI, then

Satellite

System

Relay

the

contents

The

through (TDRSS)

to each

If necessary, could

other

telemetered and

positions of the Orbiter

and to the earth's

telemetry

solar arrays the formal HST

low-gain

directly

Contingencies Predeployment Launch.

Telescope

verification.

Placement

in Space.

If the Space

subsystems

begin

the

antenna

crew will connect the RMS to one of the grapple fixtures on the forward shell. The RMS will lift HST

neuver

and

out thoroughly

diately

before

shutters

must until

4.1.3.2

instruments to launch.

the external

the HST and the fixed-head If there

areas,

the STOCC

the

problem

to the

automatically to internal

batteries

hold

the Orbiter •tern (RMS) system

tests

would

place

power.

operation power,

Tele-

Because

the

the

3.5 hours, deploy

manipulator solar

perform

the sys-

arrays. the HST

before

contingencies with the HST.

the

the

crew

Telescope

will include lifting

space.

umbilical

immediately

conducted

day,

Space

maneuver-

be

deployfail, the

Deployment

the

RMS

the

delay

cannot

for only about

the STOCC

normally

second

into

the

ma-

above

are

Figure

On the

4-2 shows

bay and

Imme-

the Space

it by the remote

ment. If predeployment Orbiter would return

4.1.4

position

the crew can disconnect

battery

a charge

would

cargo

will

Orbiter

problems

the Orbiter

arm, and activate

Only then

Shuttle

The

umbilical

were

switches

crew would

HST, holding

HST

STOCC

the crew will check the If the umbilical is con-

but not working,

it. This

of the

it to a precalculated Figure

the

Orbiter must star tracker

If power

HST from

prior to deployment, umbilical connection. nected

out

out,

procedure.

is resolved.

Predepioyment.

applied

deployment

Space

and

be closed.

in any of these launch

Hubble

prior

the launch,

power line between be connected, and

scope

on-board

check

Tele-

scope

Orbiter.

equipment

checked

telescope

shadow.

to TDRSS.

for Launch

The

the

for orbital

ing the 4.1.3.1

extending

will be ready

4.1.4.1

the 4.1.3

and

and antennas. This will complete launch and deployment, and the

to the STOCC.

the HST forward

send

bay with the RMS,

activated

the Tracking

Transmission will depend upon the the communications satellites and relative

DF-224

the

in

switching

spacecraft

will

out

prepare space.

to This

to HST

battery

of the

Orbiter

4-3

4--2

RMS

Maneuvers

Just before placing the HST will switch over power from HST batteries. At the same the Orbiter conserve which

HST

in space, the crew the Orbiter to the time, from within

the crew will turn offHST power,

removes

then

disconnect

the Orbiter

power

heaters

to

the umbilical, connection

to

the HST.The HST nowwill beon its own power, driven by the batteriesuntil the solar arraysare deployed. 4.1.4.2

Deployment

STOCC

must

high-gain

of

extend

antennas

er-accumulating

Appendages.

the and

and

solar get

and

HST

point

within

communications

in the

extension three

hours.

deployment

systems

two

the

STOCC,

will extend

The

solar

LIFTING

HST

crucial

will be the

arrays.

For

by remote

and test the solar Orbiter visual

most

procedure

of the

hours

nas. The STOCC

6.5

ARRAY

........../ .....

pow-

I 1 ) RMS

operating

SOLAR

The

arrays

the

_--

about

command,

arrays

\ \

\

and anten-

\ ]

crew, meanwhile, will give the confirmation and film the

HIGH

GAEN

ANTENNA,

procedure. The

solar

array

1.

Positioning

deployment the HST

will involve: so that

the solar

RMS(TOWARD

array 2iPR!MARY

panels

will

delayed

face

until

the

the

sun

HST

(this

could

is in full

VIEWER)

_DEPLOYMENT.SA

be

sunlight)

(30 min). 2.

Releasing using

the array

the

SSM

forward

and

mechanism

aft latches

control

unit

(5 rain). 3.

Raising the masts ment mechanisms

4.

Unfurling

the

with the primary (8 rain).

+ V2 solar

the secondary (5 min).

array

deployment

deploy-

blanket

with

mechanism RMS

5.

At the same cal power current

6.

time,

commanding

subsystem

charge

power.

Turning

the

on

(EPS)

controllers

can receive

the electrito turn

so the

Figure

OTA

and

battery

heaters

the

-V2 SA blanket

(5 min).

4-3

aperture

the antennas ow portion

Figure solar

4-3

illustrates

the

deployment

of

the

arrays.

Deployment

simultaneously. The

Deploying

DEPLOYMENT-SA

batteries

again. 7.

3)SECONDARY

on the

be opened ating,

of Solar Arrays

This will take door

latch

are being

extended, The

until the coarse the

10 minutes.

will be released

of the orbit.

to protect

about

door

during itself

sun sensors

aperture

from

while a shadwill not

are operexcessive

sunlight. At this point control When STOCC

the STOCC

subsystem the

crew

will erect

will start

magnetic gives

visual

the high-gain

the pointing

sensing approval, antenna

system. the booms

4-4

The STOCC will begin slewing tests to make certain the solar arrays move and position properly.

Again,

the

crew

will give

visual

verifica-

tion.

The

entire

deployment

because of verification three hours.

begin

procedure,

tests,

may

take

over

early

NSSC-I door

pointing

computer

Release

into

arrays

supplying

turning

on equipment

deployment

Orbit.

power,

With

the

not

the

begins

earlier

in the

The

HST

the

RMS.

into

now will be ready The

spacecraft's

the

RMS

Figure

RMS

will will

move

will adjust and

control

position. release

to be released

arm

attitude,

the attitude

the

Orbiter

45 hours

DF-224

will

in case

remain

aperture the

Space

nearby

for

the

next

of emergency.

the

the away

the

HST

STOCC

will

system

Fifteen

to monitor

minutes

spacecraft from

from

later

and

the

HST

the (see

4-4).

the

Deployment

deployment

overrides for HST

internal

manually.

commands computer's

now

will

"keep-alive"

Figure

start

up

monitors

4-4

HST

the and

Released

4-5

The

the trunnion is

Orbiter

not turn

would

astronaut switch

receive on

go into control

vital

on

to

Figure

Moves

internal

maintain 4-5 shows

ing on the power.

and

do can

the the

panel

Away

power. the

of

manual

Telescope

deployment,

bay of the SSM equipment

manually

temperature.

crew

crew

the

Space

before

systems the

locate

and

If,

Many

will use

built into the Hubble

immediately, bay,

Contingencies.

contingencies

emergencies.

power STOCC

after

process.

its correct

activate

up. The

hours

is in orbit.

Orbiter

4.1.4.4 The

24

SI C&DH

solar

STOCC

needed

The

will power

will be opened

Telescope 4.1.4.3

procedures.

the power power cargo inside section, HST correct

the crew switch-

II I

Figure

4-5

Crew

0If temperatures

EVA

begin

by Control

dropping,

the

can change orientation to improve ture of affected instruments.

If the RMS does

Panel

not hook

onto

Orbiter

the tempera-

Figure

the SSM grapple

by remote control, nection manually.

the crew can make the conIf the RMS fails completely,

it may be possible

to unlatch

the crew Figure into

the HST

push the spacecraft 4-6

shows

the

out of the Orbiter.

Orbiter

rolling

HST

ally.

the solar A crew

wrench

arrays

or the high-gain

the crew can deploy member

into a fitting

would found

drive

mechanisms.

then

crank

each

drive

the

arrays

a crew

quickly member

primary

by hand

if needed. erecting

manu-

a ratchet

The

solar array is erect and the wing The astronauts also have power

anten-

them

insert

on the

secondary could

If it appears damage member, member drive

and

astronaut until

the

is extended. wrenches to Figure a solar

4-7 array

that

could

the

remove

mechanism

array

wing

solar

the HST

array

it.

NASA

has

Figure

wing

may

to

tions

delaying

ring on the SA hull and push

4-8

the solar

planned

maneuvers from

a clamp

on the HST

away.

unbolting

soning

shows

array

a number

prevent

any the

the

a crew

before

jetti-

of workaround unexpected

release

situa-

of the

Space

Telescope. If the HST cannot atures,

systems

maintain could

within

the

spacecraft.

mary

mirror

could

if its mounts ronment.

4-6

Orbiter Rolling Out of Bay

the HST or the Orbiter or injure a crew the array can be jettisoned. A crew

member

nas not deploy,

shows mast.

the

space.

Should

erect

and have

4-6

affected

temperseriously

example,

be permanently

contract

If there

be For

internal

in the cold

is no internal

the

pri-

damaged space power

envito run

the

heaters,

attempt

the

crew

to reconnect

and restore

the

thermal

scope.

Then

study

and

the

immediately Orbiter

power

STOCC

correct

will

umbilical

to the Space would

the

have

Tele-

time

internal

to

power

problem. •

If the HST cannot one

SA to begin

must retrieve then can

manually

or rotate

masts

slew

maneuver umbilical. Before

HST

the

batteries,

the spacecraft. extend the SA them

to face

HGAs,

redeployment,

if

also

can

grapple,

the

and

crew

umbilical

If the batteries over a limited

must"

to recharge the SA

discharge past a certain point time, they cannot recharge and for

power

vital to the operation earth

shadow

duce Failure cel the

storage.

because

the

of any of these mission. Return

workarounds

to Earth.

Should

the remote

to the

manipulator,

HST

so external

3.

The payload commands

4.

The

interrogator to the HST to the

Orbiter

4-7

it be necesthe

following

all bay

and remote-

power

can replace

will send STOCC and return status

ground.

will

maintain

control within the HST is returned to earth.

Array

can-

power.

telemetry

Unbolting

could

ly latch down the telescope via the trunnion control panel. The crew will attach the Orbiter umbilical

HST \

pro-

Crew members will stow or jettison appendages, place the HST in the cargo using

2.

are

it is in

SAs cannot

sary to return the HST to earth, procedure will be performed: 1.

They

of the HST when

power.

4.1.4.5

Crew Member

Crew masts

correctly

Crews RMS

the Orbiter

will be useless

4-8

the

SA Mast •

Figure

at least

the batteries so they do not fail before produces enough power.

i!

Erecting

deploy

improperly.

the

reconnect

4-7

charging

Shuttle members the

Figure

successfully

until

temperature the

telescope

.

Just prior will close

to re-entry, to protect

the cargo bay doors the HST, and the

STOCC

will shut down

thermal

systems.

the HST

power

and

goals.

The

Center

Space

ter will run support

MISSION

Mission

OPERATIONS

Operations

six months,

covers

designed

Telescope

systems

function,

and

and

the

the testing

to verify scientific

science

and

Once

Telescope

verification. tems and

and

the STOCC

and

Verification

OTA

subsystems

End

Scientific

their

systems

to

orbital

checking the test ments. This data by the

4.2.1

Mission

the SSM

to stretch

Item (CEI)

(SV)

simi-

testing

will

approves

the HST

will have

a high

as each

priority,

instrument

and becomes

systems.

orbit,

ready

for Orbital when

the

system

operations,

such

Space

Figure

Telescope

activities

in the

Space

Telescope

Science

coordinating astronomers

The

passes

third

its system

section

The in-

Scienwere

on deployment.

Verification

(OV). The

make

up the Support

Systems

Telescope

for science

STOCC

Assembly

the STOCC

operations.

in number

lowing

summary

focuses

pointing

control

subsystem

testing HST time as point-

intense

verification

(STScI),

in Baltimore, Md., science operations,

will face strentests will be inter-

to change.

on the

process

4-8

The

fol-

testing

of the

as an example

of the

the subsystems

the

Orbiter

releases

the

HST,

will

the

tele-

scope will be in an imprecise orientation. The HST will be under Software Sun Point Control, means

sunlight

The

that

its attitude

on the solar

pointing

control

arrays

places

maximum

for power.

subsystem

compo-nents

will be turned on. The components tested to calculate and transmit data

the efforts of many international with different and overlapping

them

undergo.

After in

and subject

subsysModule

will approve

These

operations

is charted

Institute

leaves

milestone the HST in

Orbital

and Optical

4-9.

at John Hopkins University will schedule and oversee

HST

struments perform tests required to pass tific Verification. The first two milestones

which The

set for is the

tests and completes Orbital Verification. fourth milestone will be when the scientific

tems that

ing (slew) maneuvers or on-board engineering calibrations. The planned daily time allotment for

the

Verification.

telescope

complex,

its calibration Sharing

before

linked,

increasing

fully functional.

will be many

as the

milestones first milestone

the Orbiter cargo bay. The second will be when the STOCC stabilizes

4.2.1,1

by the instruearly database

Science

passes

Missions

and

observers.

begin

ground

HST

(MOC) at Goddard, communications and

to be completed

discussed

calibrat-

specifications

guaranteed-time

the

specifi-

instruments,

data produced will form the

operations

Telescope

as the

that

two orga-

Verification

uous tests before Overall

the Space

Contractor for telescope

will occur

Verification.

Verification meet

operations These

serves

Cen-

mis-

orbit

will begin

rigorously

to Contract

limits.

used

enters

will operate

larly will test the scientific ing

of the

Scientific

(OV)

subsystems

Operations responsible control.

system

Control Flight

operations.

There are four sequential Mission Verification. The

Space

Orbital

cation

op-

This is a thorough check of all sysscientific instruments. It has two

phases: Orbital

of

Space

Lockheed

Space

instruments

remainder

on its own power,

the

engineering

erational period of the sion, at least 15 years.

the Hubble

period

that

day-to-day

comprise

system.

Operations

at Goddard

the science

nizations 4.2

Telescope

(STOCC)

will be to move

6O SCIENCE

DATA

_0

40 SCIENCE RELATED ACTIVITIES 55%

30 I---

HST ON HOLD

PRIME SI OBSERV 35%

35% 20

10

m

D

SAA** ENCOUNTE R WHILE ON HOLD 12%

_

ACQUISITION

GUIDE STAR

_

ACQUISITION 5%

PREP 9%

/--SAA'" _

ENCI_NIE 1.5%

1%

"F"

PARALLEL SI OBSERV 22%

SLEW1NG 9%

ETC.* 1.5% TARGET

R

Sl CALIB 4%

NOTES: ° INCLUDES FHST UPDATES. INITIATION OF TRACKING. OTA/SSM CALIBRATION. *' SSA IS THE SOUTH ATLANTIC ANOMALY WHERE RADIATION BOMBARDMENT IMPINGES ON SCIENTIFIC OBSERVATIONS

Figure the

Space

Telescope

for communications

into and

4-9

a better

Time

orientation

telemetry.

Allocation

ETC.

for HST

based

on

means

the high-gain

the

to transmit First

the

fixed-head

mapping

the

general

Meanwhile,

the

accumulate

data

relative

star

to the

magnetic on the earth's

gyro assemblies pointing attitude

trackers

will

begin

location

of

stars.

sensing

system

telescope's magnetic

track

rate

will assess the Space Telescope (with respect to a stable refer-

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The

of the

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data,

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position.

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HST

go

to

over ground

position will adjust

more

than

computers

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antennas status

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The STOCC then will take the Space Telescope out of Software Sun Point Control and allow the rate gyro assemblies to control ing (orientation) in orbit. The

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4-9

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on at the beginning

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ager

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instruments

Figure

the

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temperature

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ty of the light reflected through the optical tem. The STOCC will use this information mirror

\

orbit

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against

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ments.

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ple functions,

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ters or focal/optics each

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use of different

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science will be cali-

4-11

are carried system,

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which

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make Many

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by another

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ground

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photometer

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the

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instruments

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data

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expected to take longer to place the image onto the small apertures and calibrate these instru-

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measures,

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reviews, posals.

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The final director,

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R. C. Bless,

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of Wisconsin

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science

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operation telemetry

mission-control

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Relay

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ties at Goddard. many

times

the

These

before,

facilities

International Ultraviolet missions in the 1970's. The

POCC

have

including

will have

the

port.

telemetry

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science

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fect

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SSC,

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example,

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Center

will

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with of

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calibration

components.

schedule

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requires

for

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important

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the

or monitor

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aperture,

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The daily science schedule will pass through the SSC, and the STOCC will match the infor-

scope from the POCC, based on specific observation objectives. The POCC will translate those

a power

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An

compromise. Some

In the

tions

is oper-

is scheduled

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indicates

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ated by the Institute and represents the astronomer's concerns, to balance the schedule. For

or the

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that

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gyro assembly

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Einstein

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can look at preliminary from the photometer to

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beam

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from

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informa-

4-15

The Data

third

important

Capture

Facility.

part of the STOCC This

is where

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The facility will reformat data from mission format, check for any noise mission

problems,

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4.2.3.1

report.

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for science

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Orbital

Hubble

mately

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altitudes

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deployment

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relay

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placed

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falls

more

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apart,

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blocks

satellites,

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the telescope

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within

receive

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mands

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data)

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orbit

coverage.

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send

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from

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with

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communication data transmission.

eight

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limited

available

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Characteristics

Three

major

affecting

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factors

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will

its

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at

orbit

to

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orbit

orbit

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of the earth. a maximum

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from

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the object

Space

shows

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as the

spacecraft

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itself

comes

viewing will earth shadow.

nominal

orbit.

orbit will be tracked

by the

will plot the spacecraft's

times

daily

Dynamics

Facility

future

in predicting

and

send

orbit

the data

at Goddard.

orbits, orbital

shadow

is If,

though

This

some

events is

at

to the will

inaccu-

such

as exit

expected

and

of the

characteris-

The

environmental

elements

tics for the spacecraft, its maneuvering characteristics, and the communications characteris-

impact on the HST orbit and other solar activities.

tics for sending and receiving data mands. These are discussed below.

upper

and

will

enough

complete

During

from earth unavoidable.

the success

solar

operating

an object,

to re-acquire

Flight

orbit

during a "nominal" 30-day period 34.5 and 36 minutes in shadow.

the object

least

at a

so that

the telescope's

to a minimum

viewing

TDRSS,

the

incline

plane

the faint

will pass into the shadow in shadow varies from

when

and

chosen

high

scope time

racy Operational

be

from

Telescope

36 minutes

--

will

on the

will

97 minutes.

help predict

4.2.3

atmopheric

play

every

The

supple-

where

The

will not decay

Space

operat-

nmi (368 kin)

orbital

directly orbit

the minimum

The

will

200

orbit

HST

drag

level

Figure

GSTDN,

provides ment

data

that

variation between

channels.

for commercial communications purposes, as television transmission. These satellites pass along STOCC.

of

HST's

multiple-access data)

system

to either

of the

communication

satellites

access

signal

the

approxi-

from the equator because will be due east from

Center.

put the sun in the

aerodynamic

communications

The

of

spacecraft

a minimum

above

to keep

orbit

will be The

between

--

light

will

km).

of approximately

drag

The

Telescope

nmi (607

ing altitude

addition, The

Characteristics.

com-

on

4-16

the

atmosphere

and

telescope,

thus

with

greatest

will be solar storms These "thicken" the

increase

the drag

accelerating

the

force orbit

Other

EARTH SHADOW

sources

affecting

zodiacal

light

starlight.

These

and

celestial

viewing

integrated

will affect

or

will be

background

the viewing

with cer-

TARGET

tain instruments, such as the light-intensity sitive High Speed Photometer. Solar-System SUN IN ORBIT EQUATORIAL LINE HST ORBIT PATH

objects

also

tioned

for

Object

Viewing.

will be affected celestial

Telescope

also must

work

parameters

for itself

and

and

decay

rate

4-13

HST

Nominal

considerably.

The

Orbit

Space

reason

Telescope

will be launched into a peak of high solar activity. This could affect the launch and orbit altitudes

required

by the

Space

Telescope

to com-

plete the first five years of the mission without falling below the 247-mi limit. If "worst-case" studies

hold,

reboost

the

the

the HST

mission

than

Space into

Shuttle

may

a higher

orbit

need

to

earlier

in

expected.

is because

comets.

tion

in orbit,

which

tion

toward

nearby

Solar

System

objects

scope

will need

object

toward to

Viewing. celestial

expose

10 hours, zone

The targets

if needed.

HST and north

and

by the

pointing

direcmost

that

the tele-

"snapshot"

of the

Tracking

inaccuracies

a blurred image observations

targets.

a

up

plane

on either of that

ZONE

1 _

.--.-.--

to

of the

side of the

orbital

celestial target

plane viewing remains

_

ORBIT

PLANE

earth. EQUATORIAL

Another

factor

celestial

targets

affecting

the

will be the

available for faint-object for an observation varies

year

and

the

HST

orbit

location plane.

of the

observation

amount

time time

the

if they of dim

viewing"

to the orbit

(see Figure 4-14). Otherwise, depends upon how long unblocked

for

A "continuous

"poles"

its posi-

orientation

detectors

up to 18 degrees south

a quick

the

However,

are so bright

are more likely to cause occur with long-exposure

NORTH ORBITAL

will be pointed

as a normal

will exist, parallel

the

Astronomers

geometric formula to decide period a target will be most HST is in shadow.

I\_..

of shadow

study. Shadow with the time of target, when visible

relative will

v, ING ,,,, ,e" zoNE-'----.---.._...,r._ _-' _,,/'/" _

a

in a given while the

Figure

4-14

.._.... _

"Continuous-Zone" Celestial

4-17

/

CONr,NUOUS I ,_""S'-'_//

to

use

PLANE

%.

of

as

off by it. The

CONTINUOUS

telescope

instrument

is changing

objects.

only

such

For example,

affects

to fix its position.

VIEWING

Celestial

HST

the

with imprecise objects

center may be try to lock onto

the

men-

In addition,

orbit

planets

System

by the factors

viewing.

position of Neptune's 21 km when the sensors Figure

Solar

Space

the outer

sen-

Viewing

_-

SOUTH ORBITAL POLE

The

Space

affect

Telescope's

the

view

maneuver the

that

30-degree

image

into

of rolls limit

attitude the

roll

object

the

may

and

require

spacecraft

(for

more

example,

a spectrographic

Lunar

also a

will

approaches

than

to place

Occultation

sensors

the

slit aperture).

within

moon.

But,

protect

the

ground

with

interior

planets

the HST will place

scope

opening's

To minimize telescope to block shadow rendering Venus.

the

falls on the of

how

i.e.,

HST. See the

HST

using after Figure

part

zone.

this exposure,

objects

sun;

which

the tele-

for a

uously

observe

netic galactic

team

of the

the

could

bright

use

that

servos,

the

the moon

for an observation.

be

HST

controls

selector

The

as an moon

between its "new-moon" phase so the occulting

moon

precedes

(see

Figure

Radiation. Energetic sources will bombard as it travels

shielding

4-15

Observing

4-18

Venus

around

will block

component

SUN SETS

Figure

star

is in shadow,

Natural different

sunset

4-15

would

degrees

the

the

and edge,

illuminated

4-16).

the

the earth the

ten

fine guidance

when

overriding

object

of the

The

away"

sensor

likely would "quarter-moon"

Venus)

sun-exclusion from

will view these

and

the sun within

50-degree

the danger

(occult)

(Mercury

by

control

occulting Tracking

Viewing.

"look

of

the

particles from the HST continearth.

much particle

Geomag-

of the solar "radiation."

and

periods. Careful scheduling will minimize the effect of the SAA on the mission, but it will have

RELATIVE MOTION OF

Z?2

some

regular

Solar

flares

impact.

are strong

accompanied The

MOON HST FOV

by bursts

earth's

magnetic

pulses field

regions,

inclination,

from

most

ticles.

flares

are

The

radiation,

of energetic

magnetic

latitude

of solar

particles.

shields

the

lower

such as the HST orbit of

these

charged

monitored

par-

regularly

by

NASA, and the HST could stop an observation until the flares subsided. The greatest physical GUIDE STARS ECLIPSED TARGET

J

AFTER

Figure

the Space

South

Atlantic

Using the Moon Occulting Disk Telescope

Anomaly

magnetic

enter

the

detectors, false data.

telescope

charged

and

emitting

strike

through

the

verification,

measure

the

instrument significant, cameras

effect

in the

will move

could

at

a

the

photon-counting

probably passes by

will not through

this

the

ability

Nonetheless,

the

may

hold precise

The

stars

trates

to

the

lock

used SAA.

onto

spectrographs if the

or the rate

on are

in the

when The

occasionally

in

the

Telescope

minutes

One

danger

guide

stars.

the

photome-

guidance

sensors

gyros

can produce

sky must

tion,

can a

direct

there

portions affected

the

or

4-17

illus-

it will take a new

a few

target

This means

be

scanned

and

a larger for

guide

the

is some of

solar

radiation the

thermally.

array

concern aft

long.

out of In addi-

that

unprotected

shroud

could

Therefore,

beyond

wings

for too

SSM

will be the

there

a certain

are

range

be limits

in angle

the SAA

scope

with

Figure

with maneuvering

of moving

sun's

encounter will last up to 25 minutes. the SAA rotates with the earth, so it earth-shadow

to move

degrees/sec

and lock onto

consideration

When

will coincide

by

maneuver.

drift errors.

of the

noise

or nine consecutive orbits, with it for six or seven or-

enters

pitch

to track

region stars.

0.22

maneuvers,

will accumulate

could

will pass through

in space

It will be able of

14 minutes.

HST

to maneuvers and time.

for segments of eight then have no contact bits. Each In addition,

rate

a roll and

also and

Space

the

image.

Space

spacecraft

devices be

bombardment

be usable

guide

radiation

that the effects

The

its orientation

the spacecraft.

baseline

90 degrees

producing

will run tests to

particle

If it appears

produced

ters

of

data.

spacecraft affect

the Institute

will change

a "hole"

and

Characteristics.

rotating its reaction wheels, then slowing them; the momentum change caused by the reaction

particles

the instruments'

electrons

Maneuver

Telescope

passes (SAA),

field,

4.2.3.2

as an

When During

activity, subsided.

DETECTORS

4-16

When earth's

danger would be crew extravehicular which would be halted until the flares

HSP

HST

as the

observation

the

the HST performs 50

a pitch

sun-avoidance

will curve

away

from

ple,

if two

targets

are

just

outside

the

50-degree

follow

4-19

degree

an imaginary

the sun.

opposed

circle

to a target zone,

zone,

the

near tele-

For exam-

at 180 degrees the

of 50 degrees

HST

will

around

general

orbital

supplemented Network

Control

schedules SUN

week.

to be filled TARGET

Center

Most

schedule,

science

requests.

will prepare

15 days before

mission

(a) Vl (ROLL) MANEUVER

communication

by specific

the beginning

HST

requests

with no conflicting

The

advance of each

are expected

TDRSS

requests

1

(VIEWING AWAY FROM SUN)

(b) V2 (PITCH) MANEUVERS (MANEUVER PLANE CONTAINS SUN)

Figure

4-17

HST

Singe-Axis

50°

/

Maneuvers 50*

the

sun

Figure

until

it locates

the

second

(see

/

l

4-18).

4.2.3.3 Communication HST will communicate Tracking

and

(TDRSS). 130 degrees

Data With apart

amount of 94.5 minutes

Characteristics. with the ground Relay

two satellites in longitude, the

contact time of continuous

The via the System

TARGET2

placed maximum

Figure

Satellite

will be up communication,

with only from 2.5 to seven minutes of exclusion," out of reach of either Figure

target

PATH OF HST SLEW

/

J

(FACING SUN BUT ANGLED 50* AWAY FROM DIRECT CONTACT)

j

4-I8

Sun-Avoidance

Maneuver

to TDRS EAST long. 41 ° W

TDRS WEST long. 171 ° W

in a "zone TDRS (see

4-19).

However, orbital communications situation

variations by the satellites will affect

to widen

the zone

HST and this ideal

of exclusion

slightly. soRs WEST s.Aoow _.s,_!o

The Goddard Control Center munication.

The

Space Flight will schedule Space

Center Network all TDRSS com-

Telescope

will

have

COVERAG)EAST SHAOOW ZO_ ZONE

a

4-20

Figure

4-19

TDRS-HST

Contact

Zones

from other spacecraft,at leastin the early part of the mission.

2.

The

ing data, nas

cannot

single

GSTDN

or science transmit

contact

factor

In practical

system

tacts

would

be

existing

at least

required

between

GSTDN

to read

data

gaps

track

Each

the communication

fine-pointing

in that

antennas

coverage

multiple-access

from

a

continuunneces-

even

will provide

via

TDRSS

command

phase

operations first

can during

at least

for rate

of the

Space

is maintenance spacecraft

in orbit.

Normal

the

95%

NASA

currently

upgraded

is developing

mission

the

science

instruments

to

objectives.

The decision-making and operational responsibility for HST maintenance, when that is required,

currently

Flight

Center

Space

Flight

lies

with

(MSFC). Center

Marshall

Eventually

(GSFC)

Figure

involved in deciding a mission.

a

Shuttle

4-20

Space Goddard

will assume shows

whether

minimum

maintenance

the

that

process

or not to schedule

Telescope.

their

in orbit.

designed

will has been

would

(MMs),

five

years,

Days

is in Figure

The Space

Shuttle

Replaceable

Unit

with

for

A mission seven

days,

activity 3 and

5. The

(EVA) generic

4-21.

-- Some

will carry Carriers

replacement

exchanged

to be replaced

in orbit

for Flight

the HST is

bay.

be scheduled

the

will perform

while

extra-vehicular

timeline

recapture

crew

payload

Space

is

maintenance

of equipment

need

HST

missions

as the nickel-hydrogen

a five-year

The

every reasons:

degradation

the HST

for

mission

the

assignments

in the Orbiter the

the

with and

Then,

maintenance

berthed

MM

mission,

will rendezvous

Space

used.

Telescope

Maintenance

equipment such

providing

extend

with

scheduled approximately would occur for several .

so

if the main

is impaired.

scientific

scheduled

while

capabilities, even

second-generation

currently

the

system advances

responsibility.

MAINTENANCE

Another

redundant

the

has been

maneuvers.

The low-gain

4.3

to replace

Telescope

equipment advances in technology may justify replacing operating equipment. For

During

orbital

communication maintenance

necessary Space

if a unit's

con-

antenna

satellite,

--

of the mission,

can function

Technology

example,

recorder -- with gaps of up to transmissions.

in communication.

with

systems

unit 3.

contacts

Each high-gain antenna will maintain ous contact with one TDRS to avoid sary

most

be The

designed

will be

three

may

equipment.

longest

of this backup

terms,

filled science tape 11 hours between

The minutes.

the large gap in time with the HST.

mission

anten-

will be eight

failure

continuation

such as loss of power or capabilities, an unscheduled

engineer-

if the high-gain

to TDRSS.

time

The limiting

will receive

data

equipment

loss endangers

The backup communication link will be the Ground Spacecraft"l)'acking and Data Network (GSTDN).

Random

(called

up to two Orbital (ORUC)

units

that

changeout)

units

during

the EVA

period.

The

following

typical

example

packages would

be

with the

existing

outlines

the pro-

after

for several

years

batteries,

with

lifespan.

cedures during

4-21

for

replacement

a maintenance

of a selected mission.

ORU

HST RETURN

I NO

M R sou cE F-[ UNSCHEDULED

SYSTEM PERFORMANCE

FAILURE

DATA

EXISTS

_"_'- [

AVAILABILITY

OF H

MAINTENANCE

SAFE

HST

POSSIBLE

LOSS

• ORUs

MODE AUTONOMOUS

H

MISSION

• SSE

ESTABLISHED

• STS

_NO

NO HST

FLIGHT

__S

DELAY

YES

IMPACT ASSESSMENTS

SCHEDULED

I

OSS

OF

M&R

SCIENCE

MISSION

RESOURCES AVAILABILITY

4""o! ! I J

TO

NEXT

MAINTENANCE

NO

I I I I •

CONTINUE



• ORUs

MISSION

• SSE

WARRANTED

DEGRADATION

• STS

UNSCHEDULED

LOSS

REDUND-



ANCY

(MISSION

MISSION CRITICAL

ETC ESTABLISH

FUNCTION

MISSION

MONITORING

! I I I

i I I I

SAFE MODE POSS,BLE CONT,NUEDEGRADED

NO

NO

--

HST

TO

DELAY

NEXT

SCHEDULED

FAILURE •

PARTIAL



LOSS NON-CRITICAL

HST

DATA

MISSION

RETURN

ORBITAL

PARAMETERS

t tN°

ESTABLISH

YES

REBOOST AVAILABILITY

REQUIRED

I

SOLAR

DATA

t

HST

M&R RESOURCES • STS

REBOOST

MISSION

_

NO

SAFE DELAY

MODE TO

POSSIBLE NEXT

MISSION " SCHEDULED CONTINUE DEGRADED HST RETURN

Figure 4.3.1

Maintenance

4-20

MM

Call-Up

Scenario

Trip Decision 3.

The

Process

Orbiter

will match

minimizing will launch

The Shuttle

and

Space Telescope on the retrieve it as follows:

rendezvous

second

with the

flight

day,

and

4.

thruster A crew

propulsions. member will

manipulator ple onto

1.

The STOCC stability,

high-gain

will report

and

the HST attitude,

whether

antennas

the

are

arrays

extended

and

or

retracted. 2.

The STOCC scope and

the aperture

the Space

system the

HST

control

(RMS) forward

maneuvering

the

berth

Flight

RMS

will

Support

the

Structure

on the base

orbit,

of the HST from

The astronaut

the camera will command

to stow the antennas close

5.

the telescope

contamination

the arm

and

remote grap-

shell.

the HST with telescope (FSS),

on

the

guided

by

of the FSS platform.

Tele-

and solar arrays

door.

4-22

When the Space Telescope the crew can tilt or rotate

is latched to the FSS, the berthed HST (see

CREW ACTMTY

nicate

DAYS

with the

RMS FLIGHT

DAY 1

Launch/On-Orbit Preparation

FLIGHT

DAY 2

Rendezvous/Retrieval

FLIGHT

DAY 3

EVA #1

FLIGHT

DAY 4

HST Reboost/Crew

Rest

arm

crew

from

inside

member

for

STOCC

through

After

leaving

their

personal

cable

that

member

the Orbiter

the

EV1

safety

wrist

along

each

protects

the

FLIGHT

DAY 6

HST Checkout/

floating

Redeployment

the

De-orbit/Landing

EVA equipment to gather tethers, two tool caddies,

FLIGHT

DAY 7

cargo

while, Figure

4-21

Figure

Maintenance

4-22).

During

vertical relative each EVA the position

and

the

Mission EVA

to the Orbiter HST is tilted

latched

to the

Timeline

the

HST

restraint

will be

cargo bay. After to a 32.5-degree ORU

EV2

(MFR)

Finally

EV2

safety

left wrist handrail.

climbs

assembly

tether

covering the

containing

manipulator

installs

it into

onto

the

to a D-ring

thermal

Figure Two crew

4-22

HST

members,

from

--

Z _oo

In Position

designated

on FSS EV1

is the ORUs

a portable

foot

and

EV2,

crew member on the HST, restraint

(PFR)

that can be placed

in receptacles

throughout

HST. from

crew member manipulator

who, working foot restraint,

EV2 the

removes passing

is the RMS and

them

to six hours On Flight through them

to EV1. of EVA

ORUs The

Orbiter

the Orbiter

on

EVA

the crew

in a 24-hour

Day 3 the EVA the

into

installs

the

RMS

MFR,

attaching

on the

EVA

suit

tethered

the

System

Bay

1 to assist

Module

out,

the

(SSM)

a tether

releases

computer

on

to the DF-224,

port

replacement removes the

attaches then

oper-

the

moves

to

the

six

ORUC.

to the Sup-

equipment

section

0

will suit up for EVA. EV1 who removes and installs working

L

blanket, DF-224,

holding

EV2, ---

foot

bay, with the IV crewmember

replacement

J-hooks

x:951

to

a miniworkstation, and a PFR. Mean-

ating the RMS. EV2 moves to the DF-224, mounted on the ORUC,

x=a92.o

from

moves

and a second safety tether to the RMS Now EV2 moves to the ORU carrier

in the cargo

ORUC

cargo

members

bay. EV1

the RMS

and

attach

grapple fixture, then configures the MFR with tool boards and portable lights and handles. one

carrier.

stowage

unstows

the

to a tethering

crew

in the cargo

bay

EV2

of the Orbiter

EVA #2

off once

the IV

with

and

tethers

DAY 5

sills and

and

IV crewmember.

the airlock,

runs

the

(called

intra-vehicular),

FLIGHT

bay

maneuvering

cargo

ORUC, is limited

period.

crew prepares

airlock,

the

which bay. They

to pass will

take

commu-

4-23

EV1

DF-224

inserts

guiderail steps

EV1

PFR

below

the

in place.

EV1

releases

the door

closed,

then

which EV1

in Receptacle

into the restraint

for STOCC

approval

door

the opens

disconnects

seven

releases

the six J-hooks

er, then

pulls

the

location

and

transfers

EV2

tethers

1, then

the suit's

six J-hooks the door.

to disconnect

is communicated

27, on the

to Bay

and locks

through wing-tab

the side of the DF-224 heater connectors. EV1

EV2.

or changing

computer.

the

just

in replacing,

boots

holding EV1 waits

the DF-224, the

IV:. Then

connectors

at

and the two wing-tab tethers to the DF-224, to remove

computer the

to the

from original original

the computits mounting DF-224 DF-224

to and

transfers Then

the EV2

replacement

takes

the

DF-224

original

to

DF-224

ORUC and installs it where unit was stowed. Meanwhile,

the EV1

EV1. to the

replacement has tethered 32.5

and

positioned

Bay

1.

the

replacement

DF-224

/

O___

in

FSS

Now EV1 engages J-hooks, attaches

and torques the connectors

tight the six to the new

I

unit, and informs the IV crewmember that the DF-224 is installed. EV1 closes the Bay 1 door, re-engages stows the and

the J-hooks and tools on suit tethers,

removes

it from

tightens them, exits the PFR,

Receptacle

Figure

27.

the cargo altitude

This operation

takes

approximately

two days

pattern,

of EV

activity

stowing earth. The

the

decision

for

charging/discharging of the

of replaced

Space

can

reboost

This EVA1

the Space

return

With

the

the

4-24). alti-

tude, and upon completion of the planned maintenance activities, the crew deploys

crew the

Shuttle

reaches

Telescope

original

in the

the

same

new

manner

as

the

deployment.

to

will

MISSION

The

Hubble

OBSERVATIONS Space

specific targets the observational

Telescope

will

study

in the sky in its lifetime. work will be highly

many

Much of technical

and very specific, such as estimating the ratio of helium to hydrogen in quasi-stellar objects

degreda-

the HST, then and its comple-

spacecraft on

the

has decayed to a higher

flight

be-

the Shuttle day

orbit. between

EVA2.

the

to a higher

maintenance

altitude,

//

For this operation, the Space latched to the ORUC keel 4-23).

Figure

will move

Telescope

orbit

acceptable

is scheduled and

(see the

Space

capacity.

two-day

Telescope's

low a minimum

bay, the Orbiter

Position

units.

Reboosting

If the

to-

to replace

upon

mission, the crew will redeploy return to earth with the ORCU

4.3.2

the

units

depending

completion

ment

working

upon the status of the HST flight configFor example, the batteries may or may

of their

After

unit

on which

not be replaced, tion

this general

the units to be replaced, the replacement unit and

removed

in Reboost

orbit

4.4

final

depend uration.

follow

with the two crew members

gether, one removing the other retrieving

HST

55 minutes. When

The

4-23

I

HST

latched

Telescope latch (see to the

will be Figure

ORUC

in

4-24

,

.

__(:,.?.

Figure

4-24

..... ,.... Shuttle

4.. Reboosting

..... the HST

(quasars)

to evaluate

the age of the quasar.

general observational Telescope include:

goals

set

for

the

But Space

Both mission examples are based on studies the Hubble Space Telescope project team. 4.4.1



Measuring

the

distance

thest away from standards to use distances •

how

chemical gaseous

us, and developing better in measuring the immense

stars

of stars,

clear explosions a star's life. Searching

that

planets

the most and

that astronomers 90% of the bulk

of

Section

these

distant

early

such

of each

there

vations

Sys-

development

of the

existence of matter and invisible matter

are

in

4.4.1.1

(see

of the

aperture

there

the Space

the Hubble

it is impossible

that represents Space

Telescope

all obserwill make.

Nonetheless, the following section approach two "typical" observations.

will

with

parallel

Planetary opportunity" by the Goddard

observation

by the

Wide

Camera,

and

study

of an exploding

High

Resolution

a

of

4-25).

The

different

will make

Telescope

Each

position

precise

pointing

To

must

a

to make HST can

increase

the the

18 minutes

stars.

If the HST

fixed-head

star

over-

trackers

coarse-pointing updates use the FGS again.

probability HST

of multiple

the

plus the time the FGSs

the guide the

center

to reposition

-- an estimated

its target,

may have before the

the FGS

90 degrees,

to acquire

shoots

flight

of

a

software

guide-star

pairs

successful allows

the

to account

for

any natural contingencies guidestar acquisition --

that might affect a such as a guide star

being

preventing

a binary

star

and

a "fine

lock"

from

getting

fore,

an observer

cludes

selection

proves

and

studying

tion process takes switches to coarse tion

to acquire

the

that inpairs.

to acquire,

to the alternate has a limited

FGSs There-

a proposal of guide-star

too difficult

sors can switch each observation

the

on the target.

can submit

a multiple

one pair

quiring The two observations selected are the study the Vela pulsar by the High Speed Photometer,

Observation.

is the time it will take

to maneuver

use

observation,

observation, and data

has an entrance aperture, portions of the HST focal

sizes in which

target,

observa-

an example

observation

sometimes-lengthy procedure for the fine guidance sensors (FGSs). In addition to the small

will present

in the steps

Figure

apertures

section

variables

in the

and

scientific instrument all located in different

acquisition,

are so many

required

Acquisition

scientific process

steps

analysis.

to specific the

Procedure

process are target acquisition and data collection and transmission,

take as

discussed

major

relate

individual

to present

Solar

for clues

tion examples to demonstrate involved in an observation.

Because

as black galaxies,

in our

The

plane

mysteri-

objects

observations

This

of

think makes up as much of the universe.

3 as they

instruments.

beginning

exploding

universe, including the before galaxies formed,

Many

the

the nu-

on many

pulsars,

origin

the

universe,

the outer

Examining to the

and observing signal

in the

quasars,

and even tem. •

by examining

for information

objects

holes,

form,

Observation

far-

composition of existing stars and of nebulae, which astronomers feel are

the birthplace

ous

objects

in space.

Studying



to the

by

If

the sen-

pair. However, total time for ac-

target.

If the

acquisi-

too long, the acquisition logic track mode for that observa-

the

guide

stars.

Field/

"target-of-

There

are three

supernova

target

a star.

Spectrograph.

transmit

4-25

basic Mode

a camera

modes

that will be used

1 will point image,

the

HST,

or spectrographic

to

then or

FINE GUIDANCE HIGH

SENSORS

+v34

RESOLUTION

OPTICAL CONTROL SENSORS

(3)

PEED PHOTOME TE R

FGS #2

r.-_

II

\

I I

\ HSP

k\

c

+V2

__

14.1

AXIS

arcmin

z I I

_ s t

ii /

FAINT OBJECT CAME RA

2 DETECTORS, SE PARATE APERTURES

4.4.1.2 Data Analysis. Once observations begin, SOGS will schedule the expected data transmission from the tape recorders, usually within a few hours of collecting the data. Status information will be readied so it can accompany the data. Data will pass from the observing instrument to the SI C&DH, where the science data formatter will convert the data into trans-

pass along the data packets to the White Sands ground terminal, which will transmit the information to NASCOM. The science data will go to the Data Capture Facility (DCF) via a NAS-

X

FAINT OBJECT SPECTROGRAPH

COM

INCOMING IMAGE (VIEW LOOKING FORWARD +Vl AXIS INTO PAGE)

HST Instrument

satellite,

for processing will receive transmitted.

WIDE FIELD/PLANETARY CAMERA

Figure 4-25

to

mittable packets. From the SI C&DH the data will pass to the high-gain antennas, which will beam the data to the TDRS. The TDRS will

! FOC

Section 2.3.1 details how the FGSs operate lock onto a guide star.

then

from

the DCF

(see Figure engineering

to the STScI

4-26). The POCC data when it is

If the Space Telescope moves out of communication with the TDRS, the collected data will go onto a Space Telescope science tape recorder for later transmission.

Apertures

photometric pseudo-image, to the STOCC. Ground computers can make pointing corrections to precisely point the HST, and the coordinates will be passed up through the DF-224 computer. Mode 2 will use the on-board facilities, processing the information coming from the larger target apertures, then aiming the HST to place the light in the chosen apertures. Mode 3 will use the programmed target coordinates in the Star Catalog or updated acquisition information to re-acquire a previous target. This is called "blind pointing" and probably will be mostly for generalized pointing and for the Wide Field/Planetary Camera, which does not require such precise pointing. Mode 3 likelywill rely increasingly on the updated guide-star information from previous acquisition attempts, stored in the computer system.

4-26

Incoming data will go into SOGS, where the data base management converts the data into SOGS format before storing the updates in the Science Institute archive. The SOGS software will examine the data for duplication and missing or bad portions of data. Bad data can be DATA

II

s,

I_

/ORS

_.

STOCC

, ST SCI

Figure 4-26

Data Transmission

Pathway

retransmitted recorders. SOGS

if

will edit

it

is

the

stored

usable

on

data;

will go into

a separate

file

and salvage,

if possible.

SOGS

used

neering

can compare

data

packets

verify

engineering

observing

instrument

flooded data.

the

data

diodes

and

editing

step

example,

software

will

wavelength

measurements

stroms

remove

and

grating

Speed Photometer the HST is in

eight-hour period. Camera will make to provide region

useless

any

and

in the STScl

checked, archives

more

precise

The

Vela

writers,

and

other

output

Observation

There

are

below

are

many

data or

can

of expected operations selected observations.

that

involved

Vela

Pulsar

study

drives,

to point

toward pulsar.

the pulsations.

magnitude

of 24,,. The

pulsar

is scheduled

The Vela pulsar observation

over several

45

1), communicating The of

coarse the

general

celestial

the pulsar

is

the observacquisition

through

targeting

region

degrees

HST will begin

Because

the

TDRS

will be based

taken

earlier

The

pointing

stars

that will place

system

will search

on

by

apertures.

or

tion, and the change provides needed for the slew. It will take

film

assemblies

the

maneuver

position.

Then

while

the

FOV

to a maximum

sensors

FGSs

the

guide pul-

speed

to settle

HST

into

remains

out

angle

of rota-

the momentum a few minutes to

and the

for the

the

the Vela

The HST reaction their

spiral-scan

search

for

the light from change

from

the

of 90-arcsec

guide

stars.

finally

are

the

stable FGS as the

type

HST's

Vela

has a

of the Vela

different

the

wheel

pulsar is a subject of great interest, because astronomers theorize that a neutron star may be producing

The

such a faint object, the STOCC and er will direct the overall target

Once

the

Space The

about

equator.

sar into the correct

planned; up the

in the

Observation.

to assist

WF/PC.

is located

of the Vela

times,

4-27

guide

stars

Telescope

observe 4.4.2.1

for the

pulsar

complete

being point

pulsar

photograph

be

sources.

observations

The

the

could

Examples

two examples

study

the spectrograph has a and pointing must be

region

new 4.4.2

in the Vela

Spectrograph. to

slewing

images WF/PC.

data

tape

than

the celestial

(Mode

errors,

for future

use, or it can be sent to printers,

Object

scheduled

in target pointing, since much smaller aperture

from

that

the

of the stars

can use the camera's

satellite.

Calibrated software

The Wide Field/Planetary a parallel observation, partly

for the Faint

to ang-

coming

problems

indicate faulty transmission, instrument troubles. calibrated

spectrograph pixels

signals

movements. for

This

data into scientific signatures. For from

to observe the pulsar earth shadow, over an

a photograph

spectrograph,

the pulfor the

that

the data.

convert

noise

carrousel

be checked

stored

that the

produced

will calibrate

step will convert telemetered form and remove instrument

Once

For

a malfunction

High while

later,

engineering

observation.

since various instruments will examine sar. The scheduled observation calls

below

A final

will

engi-

astrono-

may indicate

had

blank into a

and

so the and

the

data

with data

science

the science

to

data

will edit the data

This will be done

mers

example,

unusable

data the

for all incoming

data.

tape

for troubleshooting

by filling gaps from missing "fillers." Then it will reformat format

HST

the

scientific

pulsar.

targeted,

instruments

The

ground

the can

computers

already will have taken the camera image and computed the coordinates for the center of the pulsar. the place

These

telescope the

coordinates

as small-angle

target

HST will move

will be transmitted

into very

the

slightly,

slews HSP

needed

aperture.

measured

to to The

in a few

arcsecs.Each maneuver the total

less than three

sar

onto

light

satellite

the

will take minutes

HSP

is in position,

seconds,

to lock the pul-

aperture.

If the

the photometer

out

TDRS

immedi-

ately will begin sending light-intensity camera will send its data in one burst passes

with

data. The as the HST

of the shadow.

selected

for that

munication because

of other

50 minutes

of waiting

earth

shadow

from

the

mission

(see

Vein

path

as the Figure

pulsar

already

HST passes 4-27).

will

eight and out of

Information

follow

the

trans-

described.

may

only a few days to peak, time

to prepare

consulting

image

as

(see

Institute

an

the

rendering

will

study

4-27

HST

4.4.2.2

Supernova.

expects

targets

celestial

events,

the mission. opportune

Passes

of

Science

opportunity,

to occur

The chances target

Out of Shadow

The

are good

Institute the life of

that one such

will be a recently-discovered

supernova. The

process

pected vation. different

source The

of trackingand is different

pointing from

there

charts

and

supernova bright

in Figure

the

mission a

by star

4-28).

schedule,

limits to select newly-detected

software

will search

a for

the time exposures results from the cho-

camera

information

will

to be converted sent to the HST.

Mode

will be used.

1 acquisition

probably

the HST already shot,

the target

guide

will lock

onto

supernova

will be coarsely it will slew until

star. Then the

guide

the guidance stars.

will pass into a targeting

calculations

to adjust

data

aperture.

data

will come

Data

Capture

Light

moments

sensors from

aperture

the light precisely

A few from

pointed it captures

later

the new supernova

the for

into the the

first

into the

Facility.

at an unex-

a planned

HST may be pointing

direction,

GSSS

for the camera

unscheduled

throughout

STScI

TDRSS

produce a set of coordinates into maneuvering commands

Since Figure

The

direction.

The

extremely

guide stars, then calculate required for the best data sen instrument.

The

any current will take a

is analyzed

astronomers.

appear

supernova. SHA

with the

emergency

the camera

orbital path, and instrument favorable observation of

EARTH

be

supernova agree

in the proper

will request

while

exploding

The

must

to reschedule the STOCC

the camera

STOCC

support, might

would

information.

image of the supernova sky area with Field Camera, after the HST maneu-

vers to point

the

so there

an unexpected

director

observing astronomer observations. Then

The

unavailable A supernova

targeting

make

the STScI

"finding" the Wide

be

commitments.

little

sighting, over the next of data collection

of the sky, and the com-

takes

If astronomers

This cycle will continue hours: about 40 minutes

region

satellites

obser-

in an entirely

may be no guide

stars

4-28

The

data

accumulated

into SOGS manner.

and

be

on the supernova processed

in the

will go regular

Figure

4-28

WF/PC

4-29

Image

of a Nova

Section HUBBLE Managing

the Hubble

project is a team participants. The National tute

(LMSC),

(P-E),

and

(IDIs)

and

and/or built struments.

The

Space

Missiles

instrument

the

satellite

Telescope

Administra-

Telescope

interlocking

in the

deployment,

and

Space

Telescope

Space

AL, is the project

development that

Telescope's

5.1.1

NASA

Flight

ter. MSFC

teams designed

scientific

in-

ment

deployment, scope. seeing

launch of

charted

members

the

and

Hubble

in Fig. 5-1.

charged

Space

Telescope

period

HST. MSFC

is responsible

involved

in the

5.1.1.3

Goddard

dard

will

working

many offices and centers sharing for the development, launch and and operation

of the

Space

Tele-

from overaspects of

ground

are

detailed

with

Headquarters.

the

(AD). A maintains administers

entire

for the director

The

space

science

Orbital

deploys

for meeting

the

the cost, goals of the HST elements

Space

oversee

the

very closely developed

Flight

Center.

Scientific

with

Verification,

the Science

by Goddard,

God-

Institute

the STScl,

P-E,

Johnson

Space

Center

sible

Telescope

of the

Astrophysics

project

for

Orbiter

Once with

See the

Center.

in Houston, Shuttle

The

Johnson

TX, is respon-

Orbiter

flight opera-

HST project, JSC's responsibilities all interface requirements between and the

Space

Telescope

payload.

training for specific such as maintenance

operation.

launched, the

Center

lies

Control

Division

the

Space

(JSC),

for the Space

tion. In the also include

The

program manager for the proiect, and

resources

of the spacecraft. information about

NASA

program.

Space

Space Telescope policies and goals NASA

the

after the Shuttle

JSC also oversees crew HST support maneuvers,

below.

of Space Science and Applications in Washington, D.C., plans and directs

authority

the develop-

and

project.

or contingency

the agency's

with

cen-

system.

5.1.1.4

the

Office (OSSA),

(lead)

and Lockheed. Through the Space Telescope ground system, Goddard will control the

Responsibilities

NASA

in Hunts-

management

Verification

on tests

the project to specific responsibility for a single function, such as launching the Shuttle with the HST aboard.

5.1.1.1

(MSFC),

Mar-

of the Hubble team

operation

responsibilities

Center.

schedule, and technical performance the Space Telescope. It also manages cost and schedule of the other

These responsibilities range the financial and management

NASA

Flight

has been

of the

scientist

policy.

Center

day-to-day operations Chapter 4 for more NASA has responsibility

HST program

Space

shall

development,

are

Marshall

ville,

Corporation

management

participating

5.1.1.2

The science

Com-

responsibilities

Telescope

overall

& Space

RESPONSIBILITIES

Space

program.

oversees

Insti-

subcontractors

the Space

MANAGEMENT

Science

Perkin-Elmer

the

PROGRAM

Telescope

and

Lockheed

pany

TELESCOPE

of government and private primary members are the

the Space

(STSci),

5.1

Space

Aeronautics

tion (NASA),

SPACE

5

Space

5-1

cific crew, crew Control

the

Space (STOCC) Center.

Orbiter

Orbiter

Telescope through

Control

Johnson's

Mission

JSC will be responsible flight

and interacting manipulates Center

will communicate Operations

will

operations

for spe-

involving

the

with STOCC when the the HST. The Mission perform

Orbiter

flight

NASA

HQ

I SPACE FLIGHT MARSHALL CENTER

1 MISSILES & LOCKHEED SPACE CO.

--

--

m

HST SYSTEMS ENGINEERING INTEGRATION

_

&

HST/ORBITER/CREW INTERFACE & OPERATIONS

SOLARARRAY FAINT OBJECT CAMERA

HST ASSY & VERIFICATION

SPACE FLIGHT GODDARD CENTER

ELMER PERKIN

HST LAUNCH & ORBIT VERIFICATION

--

--

SIC&DH SUBSYSTEM

FGS SYSTEM ENGINEERING

SUBCONTRACTOR MGMT

5-1

on

the deployment and reboost flights.

Space

Kennedy Center,

launch

site

responsible placing

Space at Cape

for Shuttle

--

HST MISSION OPERATIONS

p

TDRSS

Space

flight

Telescope

and

on

most

Office

Data NASA

project

Canaveral, flights.

Telescope

NASA

FL,

is the

Kennedy activities,

also

is

such as

in the Orbiter

Facilities.

The

will rely on the Tracking

Relay Satellite commercial

SUPERVISION OF SCIENCE OPERATIONS

--

SCIENCE& ENGR DATA ANALYSIS

--

ASTRONOMICAL

HST/ORBITER LAUNCH VERIFICATION

of Space these

car-

5.1.2 The

Space major

scope science

System

satellites

communication.

Tracking

and Data

Systems

operations.

(TRDSS) (NASCOM)

Space

Telescope

Institute

of the

Institute are to and coordinate

operations

ground

Science

responsibilities

Science program

Institute's Telescope

--

FINDINGS

ground-to-spacecraft

scope Other

I

SCIENCE OPERATIONS PLANNING

Kennedy

go bay.

5.1.1.6

I

SPACE CENTER

--

Responsibilities

The

Center.

for the prelaunch

the Space

KENNEDY

II |

_LAUNCH

manages 5.1.1.5

I

HST OPERATIONS CONTROL CENTER & SCIENCE OPERATIONS FACILITY

Figure operations maintenance

SCIENTIFIC INSTRUMENTS

FAB, ASSY & VERIFICATION OTA DESIGN,

OPS

I

TELESCOPE

SCIENCE INSTITUTE

I

HST IN-FLIGHT MAINTENANCE PLANNING

HST MISSION PLANNING --

SPACE SPACE JOHNSON CENTER

SSM DESIGN, FAB, ASSY & VERIFICATION

I --

I

SPACE EUROPEAN AGENCY

I

]

counterpart

with

the

in the

Space

Tele-

manage Space

the Tele-

STOCC, Space

the

Telescope

system.

and

and

The

science

for

the

HST

5-2

program observations,

involves selecting

setting the

goals

for

observa-

using SPACE FLIGHT MARSHALL CENTER

I

I

TELESCOPE PROJECT HUBBLE SPACE OFFICE

MODULE SUPPORT PROJECT SYSTEMS OFFICE

ENGINEERING SYSTEMS OFFICE

l

t t I

!

to

and

analyze

make

Institute

has

participated

in the

prepara-

tion of the scientific instruments, development of the instruments

assisting in the from an astro-

nomical tests.

of verification

basis,

and in the creation

5.1.3

Lockheed

Lockheed

PROJECT CHIEF ENGINEER

Missiles

in Sunnyvale, LMSC

I !

vised LMSC

is the

contractor

Support

co-prime

work

contract

fabrication

Company

of the

is the the

and

MAINTENANCE AND REFURBISHMENT OFFICE

• HST DEVELOPMENT

& Space

& Space

CA,

development PROGRAM PLANNING AND _ROL OFFICE

Missiles

of many includes

Company (LMSC), for

Systems

contractor

and

design,

super-

verification

PROJECTS OFFICE FLIGHT

[

OFFICE FOR HUBSLE FLIGHT TELESCOPE PROJECTS SPACE

!

• TOTAL PROJECT MANAGEMENT • OTA DEVELOPMENT

tion

SSM DEVELOPMENT HST INTEGRATION AND VERIFICATION ORBITAL VERIFICATION OPERATIONS MAINTENANCE AND REFURBISHMENT

Figure

5-2

plans

that

interweaving

MSFC Space Organization best

cohesive and interactive the science operations and processing craft's scientific

Telescope

accomplish

all the selected

PLANNING

EXPERIMENT SYSTEMS OFFICE

those

goals,

observations

into a

schedule, conducting through the STOCC,

the data produced instruments.

]

GROUND SYSTEMS AND OPERATIONS OFRICE

t I I

SYSTEMS ENGINEERING OFFICE

RESOURCES MANAGEMENT OFF_ED

by the spaceGSFC RESPONSIBILITIES

Time

management

Institute,

because

vation

requests

teams

that

all

have

handle

will

be

it already than

produced guaranteed

this management

important

to

has far more

obser-

it can fill. In addition, the

scientific

the

• • • • •

SCIENCE INSTRUMENTS DEVELOPMENT GROUND OPERATIONS SYSTEMS DEVELOPMENT SCIENCE VERIFICATION OPERATIONS HST OPERATIONS M&R PLANNING SUPPORT

instruments

observation problem,

the

time. the

STScI

To is

5-3

Figure

5-3

GSFC Space Organization

The

development,

and

SPACE FLIGHT CENTER

LEAD CENTER

the

Module.

subcontractors.

assembly,

MSFC RESPONSIBILITIES

• • • •

all

amenable

PROJECT SCIENTIST

OFFICE OPERATIONS

l

software factors

compromises. The

ASSEMBLY oPTICAL TELESCOPE PROJECT OFFICE

sophisticated

time-management

Telescope

of

JOHNSON SPACE CENTER

NATIONAL SPACE TRANSPORTATION SYSTEMS PROGRAM OFFICE

SPACE OPERATIONS OFFICE

I

I

STS INTEGRATION AND OPE RATIONS OFFICE

FLIGHT CREW SYSTEMS OFF ICE

1 SYSTEMS INTEGRATION OFFICE

OFFICE ASTRONAUT

i

MISSION INTEGRATION OFFICE

JSC RESPONSIBILITIES: • HST TO SHUTTLE INTERFACES - SHUTTLE SYSTEMS INTEGRATION - SHUTTLE MISSION INTEGRATION • SHUTTLE

ORBITER MISSION OPERATIONS

• HSTTO SHUTTLE CREW INTERFACES - HST DEPLOYMENT - HST M&R PLANNING SUPPORT

Figure the SSM; integration

5-4

JSC

of all Hubble

Space

Space Tele-

scope components; integration testing of the HST once assembled; and support for NASA during ground, flight, and orbital operations. Lockheed will also serve as the HST Missions Operations Space control from

Contractor

Flight and

(STOCC)

(MOC) Lockheed

communicate

the missions

Telescope

5.1.4

Center.

Operations

Hughes ble

for the

testing

the

telescope

was acquired

is now

Systems,

design with

room

contractor, and

Optical

controllers

will

Organization

er coprime

at the Goddard

with

operations

Telescope

Optical

and

called

Inc. The

Telescope

and delivery other

developed

the

Hughes

company

development

the

fine

Danbury

Assembly,

from

verification for integration

components.

guidance

by

is responsi-

through

to Lockheed

HST

recently

They

also

sensors.

in the Space

Control

Center

5.1.5

Scientific

Instrument

NASA

contracted

Contractors

at Goddard. Perkin-Elmer

Perkin-Elmer Connecticut,

Corporation

Corporation the Space

(P-E),

Telescope

tigators of Danbury, project's

oth-

5-4

build

and each

investigator

with specific

subcontractors

scientific in each

instrument. case

principal to

inves-

develop The

is responsible

and

principal for the

Each KENNEDY SPACE CENTER

subcontractor

investigator team the

I

to develop design.

tractor

CARGO MANAGEMENT AND OPERATIONS

part

is the

University

OFFICE

High

VERTICAL PROCESSING DIVISION

same

that

can

sion

goals.

The

instrument

PI and

from subcon-

organization. Robert

An

Bless

responsible

Space the

fulfill

principal

development

In all cases,

teams

the

to assure

ments

the

instruments the

of Dr.

Photometer.

and

Institute

I

of the team

development

NASA

STS CARGO OPERATIONS OFFICE

cases,

of Wisconsin,

Speed

ment

I

with

final working

In some

are

example

works

as an instrument

worked

closely

development

development

for

the

the instru-

Telescope

the Space

at the

with

Science of instru-

Telescope

teams

mis-

are listed

in

Table 5-1. KSC RESPONSIBILITIES • CARGO (HST) OPERATIONS • LAUNCH OPERATIONS

Figure design

KSC Space Organization

and operation

In return, mary

5-5

the Space

time

Many

investigator during

Telescope's

instrument. receives

the first

operational

CONTRACTOR

CONTRIBUTIONS

Telescope

of the specific

the principal

observing

5.2

pri-

months

contractors

uted to the Telescope.

of

and

and their contribution in Table 5-2.

life. DIRECTORS

subcontractors

contrib-

development of the Hubble Space The contractors, subcontractors, to the project

are

listed

OFFICE

R. GIACCONI, DIR P. STOCKMAN, DEP DIR R. MILKEY, ASSOC DIR FOR PM E. SCHREIER, ASSOC DIR FOR OPS

I

_m

EDUCATIONAL & PUBLIC AFFAIRS

SCIENCE PROGRAM SELECTION

E. CHAISSON

N. WALBOM, DEP

PROGRAM MANAGEMENT R. MILKEY

] OPERATIONS

J. CROCKER P. PARKER, DEP JANUARY

]

SCIENCE & ENGINEERING SYSTEMS

SCIENCE COMPUTING & RESEARCH SUPPORT

R. DOXSEY TBD, DEP

R. ALLEN M. SHARA, DEP

M. BREDESON,

1

[

SCIENCE

PROGRAMS

ACADEMIC AFFAIRS

D. MACCHETrO

C. NORMAN S. STEVENS-RAYBURN

B. WHITMORE,

DEP

199O

Figure

5--6

STSci

5-5

DEP

Organization

DEP, AA OPERATIONS

ADMINISTRATION

H. FEINSTEIN G. CURRAN, DEP

SCIENTIFIC SPACE PROGRAMS DIRECTOR B. R. BULKIN

PROGRAM MANAGE R J. C. CARLOCK

APM.-CONTROi.S R. CROZIER MANAGER

MAINTENANCE AND REFURBISHMENT

SYSTEMS ENGINEERING D. J. TENERELLI MANAGER

R. E. GOLDMAN MANAGER

Figure

5-7

LMSC

Space

5-6

Telescope

ENGINEERING AND INTEGRATION A. J. BESONIS MANAGER

Organization

ASSEMBLY AND VERIFICATION C. J. GARDNER MANAGER

Table Instrument] Team

5-1

Faint Object Camera

Instrument

Faint Object Spectrograph

Development

Teams

Goddard High Resolution Spectrograph

(IDTs)

High Speed Photometer

Wide Field/ Planetary Camera

Principal Investigator

E D. Macchetto, European Space Agency

R. J. Harms, Applied Research Corp.

J. C. Brandt, Goddard Space Flight Center

R. C. Bless, University of Wisconsin

J. A. Westphal, California Institute of Technology

Subcontractor

Dornier Corporation British Aerospace Matra- Espace

Martin Marietta Corporation

Ball Aerospace

Space Astronomy Lab, University of Wisconsin

Jet Propulsion Lab

HUGHES DANBURY OPTICAL SYSTEMS HUBBLE SPACE TELESCOPE, OPTICAL TELESCOPE ASSEMBLY PROGRAM MANAGEMENT

VICE PRESIDENT OPERATIONS MANAGER J. D. Rehnperg

I DIRECTOR OTA PROGRAM W S. Ralford

HUNTSVILLE FIELD OFFICE COORDINATOR

CHIEFO_SCIENTIST TA.

H. J. Moeller

I

I

PERFORMANCE MANAGEMENT BUSINESS MGR.

I

SYSTEMS ENGINEERING MANAGER

AND SUPPORT MANAGER ORU MAINTENANCE r D.G. Winehell

L. J. Fad(as

R. J. Esposito

Figure

5--8

Hughes

Facey

Space

5-7

Telescope

Organization

PRODUCT ASSURANCE MANAGER E A, Mirra

Table

5-2

Space

Telescope

Aft Latch. Solar Array

P-E LMSC

Antenna Pointing System

Sperry

Battery

Eagle Picher/GE

Charge Current Controller Circulator Switch Coarse Sun Sensor

LMSC

Computer Data Interface Unit Data Management Unit Deployment Control Electronics Dish and Feed for HGA

Electromagnetic LMSC Rockwell Autonetics LMSC LMSC ESA GE

Responsibilities

Off Load Device

ESA

Optcal Telescope Assembly Optical Control Electronics Oscillator

P-E P-E

Photomu_plier Tube Etectroncs Pointing Sefemode Electronk3s Assembly Power Control Unit Power Distribution Unit

P-E

PrimaryDeployment Mechanism PrimaryMirrorAssembly

P-E

FHST Ught Shade Faint Object Camera Faint Object Spectrograph Fine Guidance Electronics Fine Guk:lance Sensor Fixed Head Star Tracker Focal Plane Assembly

Bendix Domier MMC Harris P-E Ball/Bendix P-E

Forward Latch, Solar Array

LMSC

Goddard High Resolution Spectrograph High Speed Photometer Hinge, Aperture Door Hinge, High Gain Antenna

Ball Aerospace Univ. Of Wis. LMSC LMSC

Image Dissector Camera Assembly Instrument Control Unit Interconnect Cables

P-E LMSC LMSC/P-E et al.

Latch, Aperture Door Latch, High Gain Antenna Low Gain Antenna

LMSC LMSC

MA Transponder Magnetlo Torquer

Motorola Ithaco/Bandix Schoenstadt/Bendix LMSC

MagneOc Sensing System Mechanism Control Unit Metal Matrix Mast Mull_layerInsulation

LMSC

DWA/LMSC LMSC/P-E

Frequency Elect.

Bendix LMSC LMSC ESA P-E Wavecom

RF Multiplexer RF Switch RF Transfer Switch

Elac. Power/Thermal Control Elect.

Contractor

Equipment

Contractor

Equipment Actuator Control Electronics

Equipment

Rate Gym Assembly Reaction Wheel Assembly Retrieval Mode Assembly Rotary Drive

Transco Transco Bendix Sperry Northrop/Bandix Schaeffer ESA Fairchild/IBM Cubic

SAD Adapter SI C&DH SSA Transmitter Secondary Deployment Mechanism Secondary Mirror Assembly Sensor EleCtTOnicsAssembly Solar Array Blanket Solar Array Drive Solar Array DriveElectronics Star Selector Servo

OdelJcs ESA P-E P-E ESA ESA ESA BEI

Temperature Sensor Thermostat/Heater

LMSC/P-E LMSC/P-E

Umbilical Drive Unit

Sperry

Waveguide Wide Field/Planetary Camera

LMSC JPL

SciencelEngineenng

Tape Recorder

Appendix

A

ASTRONOMICAL The

following

presents

astro-

radiating

that

relate

to specific

discus-

is. The

of the Hubble and observations.

Space

Telescope

instru-

lengths,

called

gamma

lengths,

called

radio

nomical

discussion

concepts

sions ments

briefly

CONCEPTS

lengths A.I

ENERGY

AND

WAVELENGTH

energy

are

holes.

objects

Light

energy

is one

released

matter.

The

hydrogen.

sun, The

energy

radiated

Energy

has

stream

They

rate. netic

Photons energy,

energy

portion

of electromagnetic

for

both

example, the

by that

object.

a dual

existence: called

black

For

mostly

the

more

exist together,

and

it is a

yet each

is sepa-

are discrete units of electromagmeasured by counting electrons

operate

this way,

channeling

chemically-coated released electrons.

windows

respect

waves

The

visible

from

short

violet

rays of energy.

Kelvin

degree

that will

waverays

to

to

energy burns

the

is emitted. at

a cooler,

(K) will appear

K star

wave-

A star will

corresponding the peak

a star

degree

12,000

wave-

reddish.

A

appear

blue.

Both

an even

more

ener-

stars

may still be producing

getic rays,

component of emissions, that are invisible.

such

as gamma

it is a constant

photons,

by the photons when The light detectors

3000

shortest

rays, to the longest

color at which

example,

the

waves.

visible

the

and how hot the star

from

the colors

wavelength

up its

burns

object,

released materials.

In some

except

as it burns

hotter

of particles

wave.

radiate

by an object

goes

red, the longest appear

All celestial

in the star

spectrum

and

of electromagnetic

have

plays

an important

part

study field

the universe. components

As the electric and magnetic of light propagate, they

vibration

through

counting

wavelengths

another

property

that

in the way astronomers

vibrate randomly in planes perpendicular to the direction of motion. Figure A-1 illustrates the

they strike certain used in the HST photons

Light

the

of

these

components

of

polarized

light.

ener-

gy are like waves in water. The wave's length is measured from the peak, or crest, of one wave

AGATION DIRECTION

to the

peak

of the

next

wave.

The

length

of a

_- ELECTRIC

FIELD

wave depends upon the temperature of its source. The hotter the source, the shorter the wavelength. at

Different

different

unique

elements

temperatures,

wavelength

radiate and

pattern.

energy

each

A star

has

a

will produce

INTENSITY

different wavelengths depending upon the star's temperature and on what elements exist within the

star

to become

heated

and

radiate

Figure

stars

radiate

a broad

length

spectrum.

trum

of energy

from

the

distinct

contain

many

elements,

range

of energy,

called

Astronomers coming patterns,

study

from

stars

what

Polarized

Light

energy. In

Because

A-1

stars a wave-

the

spec-

to discover, chemicals

are

A-1

certain

through

situations,

however,

magnetized

alignment according trical

and

light

waves.

of the

dust cloud

to the spatial magnetic An

light

clouds

particles

where scatters

orientation field

observer

the light

of the elec-

components looking

passes

of the

in a specific

direction

detects

path

can lead

netic

fields

this polarized

light.

to the discovery

Tracing

of gigantic

its

A.1.2

Resolving

magSpectral

in space.

resolution

closely-spaced detected. A.I.I

Measuring

features

measuring

Wavelengths

are measured in units called There are 10 billion angstrom

angunits

Wavelength

sizes

for the most

energetic

of thousands

of angstroms

Visible

light

4000-7000

range

covers

from

a few angstroms

gamma

rays to hundreds

for long radio

the

spectral

range

peaks

then

dividing

For

example,

to the

human

lengths

are

earth's

eye.

Some

blocked

by dust

atmosphere.

So

detected on earth entire spectrum object.

Figure

wave-

gases

visible

Telescope,

above the wavelengths

earth

A-2

and

the

Space

will be orbiting detect even the ments measure the ultraviolet,

visible

in the starlight

telescopes.

The

wavelengths to 11,000 _,

for a graphic

because

atmosphere, invisible HST

it

can to the instru-

from 1100 ,'_, in in the infrared. See

distance

into the wavelength.

spectral

resolution

features conditions

yield

1000

leO llllllIIIHHII I

2000

I

•,,.-_-.._W

5000

: "'" lO_m

eft lHiilllllflillll

I

3000

| 7000

of

information

2000

concerning

at the astronomical

MEASURING basic

unit

in one

year,

miles.

target.

STARS

measuring

Distance

"apparent"

star's

angular

in reality

Astronomers

the angle objects.

stellar

parallax.

calculated

Parallax

from

simple

caused

of the object.

two positions more

and

"motion"

distant

that angle

A star's

using

of an object,

the star's

against

One-half

by is the

movement

between

in position

ground

can travel

is calculated

in position

view stars

or change

stars

a

six trillion

displacement

change

from

light

parallax.

the observer's

the perceived

distance

is approximately

to nearby

the

calculate

the

the distance

which

measuring

Parallax OTA

llillllllOlll

distinguished,

distance

can

geometry

back-

is called

the

then

(Figure

be

A-3).

illustration.

--ANGSTROMS: I

the two closest be

a

physical

when

is just a small portion of the of energy radiated by that

The Hubble

strongest

are invisible

of the

can

by

that

spectral

The

wavelengths

can be

is calculated

from

Angstroms.

electromagnetic

well

spectrum

between

that

star is the light year:

Most

how

you can see separate wavelengths at 2001 ,_, 2002/_, and so on. These

A.2

waves.

in the

resolution

the distance

means 2000/_,

in one meter. (Another measurement is the nanometer; there are 10 A per nanometer.)

determines

Spectral

wavelength Wavelensths stroms (A).

Wavelengths

t 10,000

| 12,000

stars

measurements

can

relatively

near

(650

light years).

be made

us, generally

only

within

for 200

• • I t

parsecs

I

30,000

the

parallax

Other

F/PC _

tures and distance.

FOC

angle

methods

For greater

is too

exist,

intensity

small

distances, to

measure.

including

using

tempera-

of

to

light,

extrapolate

FOS -,,-HRS -_

Another

HSP----_

tial

type

resolution,

instrument FGS

Figure

A-2

HST

Wavelength

Ranges

A-2

of measurement, determines

forms

an image.

the fineness

of detail

the

angular

resolution,

can

appear

and

angular how

clearly

an

It is a measure

of

in the image. the

or spa-

closer

still be distinguished.

The

greater

two

objects Angular

is how

bright

the

star

would

appear

if it were

viewed placed at a standard distance (10 parsecs). Hence, absolute magnitudes compare the FROM _

POSITION

PHOTO

A

intrinsic

luminosities

dilution

of brightness

Magnitude

TAKEN

ures

objects.

inverted: FROM

TAKEN POSITION

(low

B

by

measurement

large

the

distance.

from

minus

fig-

to plus figures

for

magnitude

positive

brightness)

increasing

objects

The

removing

goes

for the brightest

faint PHOTO

of objects,

scale,

numbers

thus,

indicate

is

faint

objects.

EA RTH' ORBIT

For example, "1 AU

=

DISTANCE

FROM

EARTH

TO

nitude,

SUN

but if you viewed

standard

A-3

Calculating

a Star's

be

visible

is measured

in terms

barely

ible to the unaided nitude Palomar

of the

compo-

of a circle: 360 degrees, 60 arcminutes up one degree, and 60 seconds of arc

make

up one

at 28my

the

angular

times

earth-based mers measure

resolution

better

than

and arcminutes.

stability

of the

in arcseconds.

See

The

(magnitude)

COMPLETE

of

tion. how

the with

Magnitude

ent and

absolute.

bright

tion made

6 apparent

mag-

_360 _'_

IN ONE

CIRCLE

_.._

°

(/(_u-

_

DEGREE

the

telescope

Figure

/_-_ _J0.002"

Further,

the

Figure A-4

Angular

UNIVERSE

EXPANSION

A.3 One

a star

of a celestial

is measured

of the

by

a

two ways: visual

appears

without Absolute

magnitude any

explosion P. Hubble,

appar-

named, is

correc-

expansion distance Law.

magnitude

A-3

key

issues

Telescope

Currently

instrumenta-

Apparent

for its distance.

object

measured

appropriate

MEASURES RESOLUTION BETWEEN STARS

ANGULAR DISTANCE

Measurement

is calculated

A-4.

parameters the

--

largest astronofield of

Space brightness one

eye is about

of

by Mv; star vis-

between

telescopes. In addition, the scientific instruments'

view in arcseconds

telescope,

at a magnitude

or fainter.

stars is measured in arcseconds by the Sis. The finest spatial resolution obtainable with the HST is about one-hundredth of one second of

is

the

to to

IN ONE

pointing

(the

arcminute.

To illustrate,

ten

10 parsecs magnitude)

Parallax

nents make

arc,

mag-

(my); the Hale Telescope on Mount detects stars at 23my; the HST will see

360 DEGREES

resolution

it from

for absolute

visual

+ 4.85. Absolute magnitude is signified apparent magnitude by my. The faintest

stars Figure

apparent

distance

sun would Note that the foreground star in Position B appears to have shifled position with respect to the 'fixed" background stars by an angular displacement of 2p. The parallax of this star is "p", measured in seconds of arc; it is the angle opposite to and bounded at the star by the baseline distance 1 au.

the sun is-26

the

is the

future

universe

astronomers for equals

of the

is expanding

by the universe. from

call the Big Bang.

whom

calculated from

for investigation

the that

a constant

us. Figure

Space the

Edwin

Telescope

velocity (H) times

A-5 charts

the

of

is that

a galaxy's the Hubble

Astronomers 150,000

expanding,

>I-O

._ loo,ooo >_

STARS

that

but possibly

the

more

after

the

Big Bang.

If it slows

verse

may eventually

fall back

Crunch."

"_

calculate

One

indication

universe slowly

is still

than

enough,

right

the uni-

on itself

of a slowing

in a "Big rate

of ex-

pansion would be a decrease in the Hubble constant. To confirm this, however, astronomers o

, ,

50,000

VIEWER

..--

500

1000

1500

DISTANCE

(MEGAPARSECS)

must

measure

requires galactic

The Hubble

velocities

accurately,

which

distances (called

redshifts)

and

in

turn

receding accurately.

Only then can astronomers compare distances and redshifts, through studying galactic move-

2000

ment, Figure A-5

H

measuring

rate

Law

to see whether of expansion.

Hubble

A-4

Space

the universe This

Telescope.

is a major

is slowing goal

its

for the

Appendix

B

ACRONYMS/ABBREVIATIONS

A AB

Angstrom Aft Bulkhead

ACE

Actuator

Control

Electronics

ACS

Actuator

Control

Subsystem

AD

Door

Al

Aperture Aluminum

AS

Aft

BCU

Bus Coupler

C

Celsius

CCC

Charge

CCD CDI

Charge-Coupled Command Data

CEI

Contract

CIT CMD

California Command

cm

Centimeter

CPC CPM

Computer Program Command Central Processor Module

CPU

Central

Processing

CRT

Cathode Coarse

Ray Tube Sun Sensor

CSS

Shroud

Unit

Current

Controller

End

Device Interface

Item

Institute

of Technology

Unit

CU

Control

Unit

CU/SDF

Control

Unit/Science

DCE

Deployment

DCF DIU

Data Data

DMA

Direct

DMS

Data

Management

Subsystem

DMU

Data

Management

Unit

EBA

Electronics Bay Assembly Electron Bombarded Silicon

EBS ECA

Control

Capture Interface

Electronics Electronics

EOR

End

EPS EPTCE

Electrical Electrical

ES

Equipment

ESA EVA

European

Formatter

Electronics

Facility Unit

Memory

ECU

Data

Access

Control Control

Assembly Unit

of Record

Extravehicular

Power Power

Subsystem Thermal Control

Section Space

Agency Activity

B-1

Electronics

F

Fahrenheit

FCA FGE

Figure Control Fine Guidance

Actuator Electronics

FGS

Fine

Sensor

FHST

Fixed

Head

FOC

Faint

Object

Camera

FOS

Faint

Object

Spectrograph

FOSR FOV

Flexible Optical Field of View

FPS

Focal

FPSA

Focal Plane Structure Forward Shell

FS FSS ft G/E

Guidance Star

Plane

Flight Feet

Solar

Support

GGM

Gravity

GSFC

Goddard

GSTDN

Ground

HGA

High

Gain

HRS

High

Resolution

HSP

High

Speed

HST

Hubble

Hz

Hertz

I&C

Instrumentation

IBM

International

IDT

Image Inches

Gradient Space

Mode Flight

Spaceflight

(Maryland) and

Data

Network

Spectrograph

Photometer

Space

Telescope

(Cycles

per Second) and

Communications

Business

Dissector

Input Output Infrared

JPL

Jet

JSC

Johnson

k

Kilo (1000)

kbytes

Kilobytes

kg km

Kilogram Kilometer

KSC

Kennedy

lb LGA

Pound

Propulsion

Gain

Center

Tracking

Antenna

IR

Low

Assembly

Structure

Graphite-Epoxy General Electric

IOU

Reflector

Structure

GE

in

Tracker

Space

Space

Machines

Tube/Instrument Unit

Laboratory Center

Center

Antenna

B-2

(Subsystem) Corporation Development

Team

LMSC L

LOS

Lockheed Missiles Line of Sight

LS

Light

m

Meter

MA

Multiple

MAT M&R

Multiple Access Transponder Maintenance and Refurbishment

MCU

Mechanisms

Control

MDB

Multiplexed

Data

MgF 2 MHz

Magnesium

Fluoride

mi MLI

& Space

Company,

Shield

Access

Unit

Bus

Megahertz Miles

mm

Multilayer Millimeter

MM

Maintenance

MMC MP

Martin Marietta Corporation Maintenance Platform

MR

Main

Ring

MRA

Main

Ring

MSFC

Marshall

MSS

Magnetic

Sensing

MTA

Metering

Truss

Assembly

MTS

Metering

Truss

Structure

MU

Memory

Unit

Mv

Absolute

Visual

Magnitude

mv

Apparent

Visual

Magnitude

NASA NCC

National Aeronautics and Space NASA Communications Network Network Control Center

nm

Nanometers

nm NSSC-I

nautical

miles

NASA

Standard

Spacecraft

OCE

Optical

Control

Electronics

OCS

Optical

Control

Subsystem

ORU

Orbital

Replaceable

OTA

Optical

Telescope

P-E

Perkin-Elmer

PC

Planetary

PCEA

Pointing

Control

Electronics

PCS

Pointing

Control

Subsystem

PCU

Power Photon

NASCOM

PDA

Inc.

Insulation Mission

Assembly Space

Flight

Center

System

Administration

Computer,

Model-I

Unit Assembly

Corporation

Camera

Control Unit; Power Detector Assembly

Assembly Convertor

B-3

Unit

(module

of DF-224)

PDM PDU PI

Primary Deployment Power Distribution

Mechanism Unit

PIT

Principal Processor

PM

Primary

Mirror

PMA

Primary

Mirror

PMT PN

Photomultiplier Pseudo-Random

POCC

Payload

PSEA PWR

Pointing/Safemode Power

RAM

Random-Access

RBM

Radial

RGA RIU

Rate Gyro Assembly Remote Interface Unit

RM

Remote

Module

RMGA

Retrieval

Mode

RMS

Remote

ROM

Read-Only Memory Reed-Solomon

RS RSU

Investigator; Payload Interface Table Assembly Tube Noise

Operations

Control

Center

Electronics

Assembly

Memory

Bay Module

Gyro

Manipulator

Assembly System

RWA

Rate Sensing Unit Reaction Wheel Assembly

S&M

Structures

S/N

Signal-to-Noise

SA SAT

Solar

and

Mechanical

(Subsystem)

Ratio

Array

SAA

Single South

SAD

Solar

Array

Drive

SADE

Solar

Array

Drive

Electronics

SADM

Solar

Array

Drive

Mechanism

SBA

Secondary Baffle Stored Command

SCP

Interrogator

Access Atlantic

Transponder Anomaly

Assembly Processor

SD SDF

Science

Data

Science

Data

SDM SI

Secondary Scientific

SI C&DH

SI Control

SiO2 SIPE

Silicon Scientific

Instrument

SM

Secondary

Mirror

SMA

Secondary

Mirror

SPC

Stored

SSC

Science

SSE

Space

Formatter

Deployment Instrument and

Data

Mechanism Handling

(Subsystem)

Dioxide

Program Support Support

Payload

Enclosure

Assembly Command Center

Equipment

B-4

SSM SSM-ES SSP SS STDN STINT STOCC STS STScl TCE TCS TDRS TDRSS TiO2 TLM TRW TYP UCSD ULE m UV

Support

Systems

Module

SSM-Equipment Standard Switch

Section Panel

Safing

System

Space (flight) Tracking Standard Interface

and

Data

Space Space

Telescope Operations Transportation System

Space

Telescope

Science

Network

Control

Center

Institute

Thermal

Control

Electronics

Thermal

Control

Subsystem

Tracking

and

Data

Relay

Satellite

Tracking Titanium

and Data Dioxide

Relay

Satellite

System

Telemetry Thompson

Ramo

Woolridge,

Inc.

Typical University

of California,

Ultra Low Micrometer, Ultraviolet

Expansion one millionth

V V1,V2,V3

Volt

W WFC WF/PC

Watt

HST

Wide

San

of a meter

Axes

Field

Camera

WT

Wide Field/Planetary Weight

ZOE

Zone

Diego

Camera

of Exclusion

B-5

Appendix GLOSSARY

C

OF TERMS

-A-

Acquisition,

target

Adjusting the HST ment's aperture.

position

to place

incoming

target

light

in an instru-

Aft

The

Altitude

Height

Aplanatic

Image

Aperture

Opening

Arcsec

A wedge of angle, makes up the sky.

1/3600th of one degree, in the 360-degree "pie" that An arcminute is 60 seconds; a degree is 60 minutes.

Apodizer

A masking

that

Astigmatism

A defect

Astrometry

Measurement

Astrophysicist

Scientist

Attitude

Orientation

rear

of the

spacecraft.

in space. corrected that

everywhere allows

device that

who

in the field

light

to fall onto

blocks

prevents

sharp

of star

positions

studies of the

the

stray

of view.

an instrument's

optics.

light

focusing. in relation

physics

spacecraft's

To other

stars

of astronomy. axes

relative

to the

earth.

-BBaffle

Material

that

extracts

stray

light

from

the

incoming

image.

-CCassegrain

A type of telescope longer focal length

that reflects or "folds" the incoming in a short physical length.

Changeout

Exchanging

Collimate

To straighten

Coma

Image

Concave

A mirror

surface

that

bends

outward

to expand

Convex

A mirror

surface

that

bends

inward

to concentrate

Coronographic

A device

that

a unit

light

to have

on the satellite.

or make

abberations

parallel

that

allows

two light

paths.

give it a "tail".

viewing

a light

object's

an image. an image.

corona.

-DDiffraction Drag,

grating

atmospheric

Split Effect

light

into

a spectrum

of atmosphere

of the

that slows

(3-1

component

a spacecraft

wavelengths and forces

its orbit

to decay.

a

-E-

Electron

A small

Ellipsoid Extravehicular

A surface Outside

particle

of electricity.

with

only circular

the spacecraft;

planes.

activity

in space

conducted

by suited

astronauts.

-F-

Focal plane

The axis or geometric telescope.

Hyperboloidal

A slightly deeper primary mirror.

plane

curve,

where

the

mathematically,

incoming

light

is focused

than

a parabola;

by the

shape

of the

that

is not a

-l-

Interstellar

Between celestial objects; often star, such as clouds of dust and

refers gas.

to the matter

in space

-LLight

year

The distance

Luminosity

The

traveled

intensity

by light in one year,

of a star's

approximately

six trillion

miles.

brightness.

-M-

Magnitude,

absolute

How

bright

Magnitude,

apparent

How bright distance.

a star

appears

the star

would

without appear

any correction if it were

viewed

made

for its distance.

placed

at a standard

-N-

Nebula

A mass of luminous lar nova.

Nova

The

explosion

interstellar

dust and gas, often

of a star. -O-

Occultation

Eclipsing

Orientation

Position

one

body

in space

with

another.

relative

to the

(;-2

earth.

produced

after

a stel-

-pParallax

The "apparent" angular movementof an object, causedin reality by the observer's movement, not the object.

Photon Pixel

A unit of electromagnetic energy.

Polarity

A single element of a detection device. Light magnetizedto movealong certainplanes;polarimetric observation studiesthe light moving along a given plane.

Prism

A device that breaks light into its composite wavelengthspectrum. -Q-

Quasar

A quasi-stellar

object

of unknown

origin

or composition.

-R-

Radial

Perpendicular to a plane; i.e., instruments from the optical axis of the HST.

Reboost

To boost decayed

the

satellite

because

back

into

placed

its original

of atmopspheric

at a 90-degree

orbit

after

orbit

has

drag.

Resolution, spectral

Determines how well closely-spaced can be detected.

Resolution, angular

Determines

Ritchey-Chretien

A type of Cassegrain (folded) telescope where both primary mirrors are hyperboloidal to correct for image aberrations.

how clearly

the

angle

features

an instrument

forms

in the wavelength

spectrum

an image. and seconary

-S-

Spectral devices

A spectrograph is an instrument that photographs the spectrum of light within a wavelength range. A spectrometer measures the position of spectral lines. A spectrophotometer determines energy distribution in a spectrum.

Spectrum

The

wavelength

range

of light

in an image.

-T-

Telemetry

Data

and

commands

sent

from

the

spacecraft

-U-V-W-

Wavelength

The

spectral

range

of light

0-3

in an image.

to the

ground

stations.

Appendix NASA

The

Contract

proposed scope

SPECIFICATIONS

End

Item

by NASA and

demands

the are

ce/operating

requirements,

duling

and

In addition,

accumulates, new ments will arise.

D.1

18

HST

Position.

The

project

outside

require-

going

within

analyses,

most

listed

trade

important

below,

the consideration

studies,

of

and evaluations.

system

requirements

Door. the

The door

modes tem and

are

coarse

object

and

tracking,

The

fine

PCS

door

scanning,

will remain

slew

to within

even

if the

sun is normal

open,

70R

or to within

Management

5000

bytes

operating

bytes

(Mb)

solar-sys-

engineering

pointing,

will close

of the V1 axis. During

limb of the earth moon.

Data

System.

opening,

but

of the

the

bright

15R of the bright

are

by system.

Control

will be no direct

roll on the V1 axis.

reprogrammable, Pointing

positions

into the aperture

20 degrees

PCS will not

on the V3

of the sun -- with

a five-degree

operation,

mission

for

position

plane

Viewing

50 degrees

Aperture

REQUIREMENTS

The

more

spacecraft

the sun in the V1-V3

sunlight with

reflect

minutes

normal

side of the spacecraft.

this

two

settling.

as the mission

about

HST will slew 90 degrees

with

will place

mission-derived

requirements

the

minutes,

viewing/sche-

PERFORMANCE/OPERATING

These

TELESCOPE

The

performan-

and

knowledge

in

Tele-

instruments.

SPACE

For maneuvering,

of the sub-

in two categories:

requirements.

progresses

Space

on each

scientific

requirements

THE HUBBLE

Specifications

for the Hubble

put exacting

systems

(CEI)

FOR

D

maneuvering,

OTA,

Subsystem. with

(words) data.

data,

is of

125 million

and

It will receive

engineering

DMS

capability

for commands,

for science

and SSM

The

a storage

12.5

Mb for

and merge

SI,

data.

contingency. Instrumentation

In Coarse

Pointing

the PCS will point 99%

of the

time.

PCS will place aperture

to within In Fine

a target

of the more

Object minimum

0.007

Tracking

30 arcsec

of a target

Pointing

Mode

of 0.01 arcsec The arcsec.

Mode,

of three

with an angular second.

the

the

arcmin

velocity

FGS), the

in any SI entrance

observation.

than

(without

star

with an accuracy

length move

Mode

Subsystem.

for the

image

cannot

In Solar

System

PCS will provide tracking

a

mission orbit.

square

for an aperture

at a speed sized

scan

fields

up to 1

of up to 40 arcsec/sec,

from

The

minimum

time is 20 minutes

Electrical

the HST should

(I & C) will

use

the

possible

of scientific

transdata per

per

of 2800 arcmin

subsystem

single-access channel. The system should be able to transmit science and engineering data

Power

can provide For scanning,

Communication

I&C

multiple-access channel for commands, tracking, and real-time engineering telemetry. High data-rate scientific data will transmit via the

simultaneously.

for objects

of up to 0.21 arcsec

and The

0.1 to 10 arcsec.

than

D-1

a maximum

W during

Sis for two years, battery

charge 20%,

Subsystem.

even

average

each even

drain

orbit if one

over

with

The

solar power

output

for the OTA

and

battery

The

24 hours one

arrays

battery

fails.

will be less out.

The

battery

charger

can

recharge

batteries

com-

completely

within

the

orbital

Control

Subsystem.

tem

is passive,

protecting

the

OTA,

and

shroud

Sis, power

thermal

all SSM

SI C&DH.

can accommodate

sipating

The

loads

sys-

equipment,

The

heat of 300

SSM

radiated

aft

by dis-

to 500 W.

Arrays.

in any

The

of

temperature.

face

period

will do

together

is an

power,

operational

thermal,

OTA. The energy

and

OTA

from

sec radius,

scientific

instruments

used based

data-management

can capture

a star held

decision

70%

(starlight)

on

within

for up to 24 hours.

a 0.01 arcThe

optical

image will be at least 38% at 1216 A and 55% at 6328 A; higher spectral ranges make up the rest to 70%. single

The

OTA

object)

nal-to-noise

can

of (S/N)

integration

time.

laxies,

surface

the

25 mv/arcsec

at

resolve least

ratio

point 27my

brightness

2, resolved

with a S/N ratio time.

sources with

of 10 after

For extended

(a

a sig-

four

hours

objects

like

can

be

at least

0.25

arcmin

to at least

of 10 for 10 hours

the

sun within

ga-

integration

basic

viewing

ing

system

using

certain

objects,

such

as the

moon

with

and

stray

earth,

light

can

opening,

and

or when

lunar-eclipse The

South

of weak

Atlantic

terrestrial

FGS

will

detect

guide

charged

of

14my

target

can stars

calculate

the

in the

FOV

angular

position

within

10 minutes.

are within be as

impacting calculated

(SAA)

is a region

particles

to reach

noise the

low alti-

by these

spacecraft other noise.

allows

WFPC and FOC and FGS opera-

generated

by formula.

which

goes

par-

beyond

Loss of FGS pointSis normally

oblivi-

or

brighter. The time from search to detection, for a 30-arcsec radius, is 150 s. In addition, each FGS

ticles

when

and earth

field

ing could also impact ous to this radiation stars

telescope

observation.

magnetic

limit

The

the

an

Anomaly

degrees

earth.

or light-reflect-

observations.

the

of the sunlit

sun flood

aperture. Exceptions may authorization, such

tions,

70 degrees

to avoid above cervia the

guidelines.

ruin

the moon

15 degrees of the given special

energetic

and

are

Requirements are to avoid observations when the sun is within 50 degrees of the aperture

Stray light at the focal plane will be less intense than a 23Mv star when the HST points within 50 of the moon,

sur-

5-5/8 degrees solar array

requirements

could preclude and calibrations,

15 degrees

cell

degrees.

less than during

tudes. This observations

of the sun,

assumes

five

bright objects, curtail observations tain noise levels, and communicate

Bright

of the incident

4000

REQUIREMENTS

TDRS

needs.

will provide

VIEWING/SCHEDULING

The number

arrays

Positioning maneuvers cannot be performed

of 750 W for

10-minute

The solar

This

faces

D.2

three seconds no harm.

limits.

designed

with

power

is within

two years in orbit, even loss factors, at the

operation.

A peak

of

W or more at 34 V after with diode and other

Sis, SI C&DH. Scientific instrument power will be less than 150 W for 28V, or 530 W when used the SI C&DH.

average

average

of 803 W as long as

five orbits. Solar

Thermal

with an orbital

665 W for 27V, with a peak

pletely every orbit during normal conditions. After an abnormal roll maneuver, battery energy will replenish

The OTA will operate

of 10

TDRSS

"limb"

D-2

scheduling

with the STOCC, also can affect can block

impacts

any communication

and atmospheric communications. transmission

interference The earth

if the HGA

beam

a

is intercepted affect

by the

limb.

communications

antennas.

Solar

static

for the TDRS

No transmission

TDRS

is in earth

within

radio-frequency

is possible

shadow,

or when

also can or ground when

the

HST

the is

interference.

O-3

STScI

administration

needs

will dictate

requirements.

or individual other

viewing

observation or scheduling

Appendix ORBITAL Table

E-1

lists

component

each

considered

Hubble

Space

a replaceable

Description

E

REPLACEABLE

Telescope unit,

the

"lhble

E-1

UNITS

number of each and its location

HST

No

Location: (1, SSM

Battery

6

(2,3,

FGE

3

(D,F,G,

SI C&DH

1

(10,

RWA

4

(6,9,

SSM

RSU

3

SSM

Shelf

RGE/ECU

3

(10),

SSM

Computer

carried

ORUs

1

DF-224

component on-board.

(Bay)

or Other

ES)

SSM

ES)

OTA

SSM

ES)

ES) ES)

Shelf

12

(4), SSM

Shelf

Box

2

Fwd face

of SSM

SA (Stowed)

2

Along V1, +V2

RBM

3

In FPSA,

+ V2,

(FOS/WFS)

V3 Radial

Bay

WF/PC

In FPSA,

-V3

Radial

Bay

HRS

In FPSA,

Axial

Bay

1 (+V2,

FOS

In FPSA,

Axial

Bay 2 ( + V2, -V3)

FOC

In FPSA,

Axial

Bay 3 (-V2,

-V3)

Axial

Bay 4 (-V2,

+ V3)

Fuse

Plug

Diode

HSP

1

In FPSA,

DMU

1

(1, SSM

ES)

MAT

2

(5, SSM

ES)

SADE

2

(7, SSM

ES)

TR

3

(5, 8, SSMES)

EP/TCE

1

(H),

OTA

ES

DIU

4

(B), OTA

ES

OCE

1

(C),

ES

MCU

1

(7, SSM

ES)

SAT

2

(5, SSM

ES)

E-1

OTA

ES

& +

+V3)

on the HST,

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