Micro Gravity Research Program Infopage

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MICROGRAVITY RESEARCH PROGRAM

NASA Glovebox Program Science in a Box W h e n you p u t science in a box, all k i n d s of things are possible. O f course, this box is a good deal more than just an ordinary cube. Astronauts can place their hands inside it, add and remove experiment components, and manipulate experiments within it all while the box remains sealed. It's not magic, but it is a powerful research tool. This device, called a glovebox, offers an enclosed work space for investigations that may be affected by — or m a y adversely affect — a spacecraft's crew or the spacecraft environment.

Astronaut Shannon Lucid, Cosmonaut Yuri Usachev, and Cosmonaut Onufrienhp, with the NASA glovebox on Russian Space Station Mir.

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T h e glovebox has been ideal for microgravity experiments that do not require very large or specialized equipment. It has also served well as a way to test science concepts and hardware before investments a r e m a d e in t h e d e v e l o p m e n t of costly equipment. T h e basic glovebox design includes a central port w i t h a n airlock for e q u i p m e n t installation a n d r e m o v a l . E x p e r i m e n t s can be m o u n t e d to t h e floor or walls of t h e glovebox, elevated by jacks, or held d o w n by magnetic bases or strips. Two specially sealed openings equipped with rugged gloves allow an astronaut conducting an experiment to p u t his or her hands inside the sealed chamber. T h e heavy gloves can be exchanged for surgical ones to accommodate more delicate procedures. A large w i n d o w on top of the box allows activity inside the chamber to be viewed by the astronaut and recorded by cameras. Air pressure levels inside the chamber are m a i n tained at lower levels than outside air pressure so that if an accidental leak of gases occurs, air will be suctioned into the chamber rather than leaked out of it. A special air filtering system provides b a c k u p in case of a major failure. T h e s e precautions are necessary because some glovebox experiments involve hazardous substances. T h e first glovebox was designed by the E u r o p e a n Space Agency (ESA) in an agreement with N A S A that allowed E S A to use the facility o n the space shuttle with n o exchange of funds between the t w o agencies. T h e success of the glovebox p r o g r a m is largely linked to the adaptability of the facility. T h e design has allowed the glovebox concept to be adapted to both the shuttle's Spacelab m o d u l e a n d m i d d e c k area, w h e r e gloveboxes facilitated microgravity investigations

on 7 missions, a n d t h e Priroda m o d u l e of Russian Space Station Mir, where one glovebox logged over 21 m o n t h s of operation.

Support for Better Science T h e ability of the glovebox to offer c o n t a i n m e n t , the opportunity to manipulate experiment components on orbit, shorter development time for experiments that can m a k e use of its multiuser resources, and the chance to test the operation of h a r d w a r e prior to m a k i n g costly investments has proven valuable over the years.

C o n t a i n n n e n t — Special care is required w h e n scientists wish to study certain kinds of substances. In one such investigation, researchers wanted to use a microgravity envir o n m e n t to combine t w o materials, ceramic particles and a liquid metal, to form one n e w material that would have n e w properties. T h e samples u n d e r investigation required the glovebox's unique containment capabilities for t w o reasons: to ensure that any leaks of liquid materials could be contained, a n d to prevent potentially harmful materials from affecting the crew or the spacecraft. While most liquid metals that microgravity scientists study are not toxic, the metal in this investigation, biphenyl, is. W h e n toxic substances are in use, three levels of containment are required to ensure safety. T h e experimenter provides the first level of containm e n t — in this case, the ampoule containing the t w o materials. T h e glovebox provides t w o levels of containment — its sealed chamber and airlock system. W i t h these barriers in place, the glovebox offers an extra m a r g i n of safety in studies of liquids as well as materials that may be toxic if touched, ingested, or aspirated. solidification front

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As liquid metal solidified, particles dispersed in the liquid were either pushed ahead of or engulfed by the solid material. Investigations of liquids and toxic materials require three levels of containment for safety.

M a n i p u l a t i o n — A n investigation of the effects of low gravity o n thermocapillary flow in fluids was aided by t h e ability of the astronaut conducting the experiment to place his hands inside the glovebox and m a k e fine adjustments to the e q u i p m e n t for the experiment so that a variety of factors could be examined to determine their influence on experiment results. E x p e r i m e n t variables included such changes as the addition of heat a n d the altering of the acoustic forces that

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Proof of C o n c e p t — Conducting complex science often requires developing tools that can function very precisely. Researchers have used the glovebox to test systems that will allow t h e m to study the effect gravity has on b u r n i n g fuel droplets. To conduct droplet combustion experiments, researchers had to develop a system to dispense a droplet of fuel of a specific size, hold it in position so that its burning could be recorded by cameras, and develop instruments capable of measuring the size of the flame that was produced, the fuel's b u r n rate, and total b u r n i n g time. Glovebox studies on fiber-supported fuel droplets proved the feasibility of burning a single droplet and returning data on the results. This research in turn m a d e it possible to pursue a m u c h m o r e complicated p r o b l e m — burning unsupported droplets — by providing proof that the i n s t r u m e n t s w o r k e d repeatedly and reliably. Research on b u r n i n g fuel droplets in m i c r o gravity may lead to ways to decrease pollutant p r o d u c t i o n from combustion engines, which provide the majority of the world's power.

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were used to position the liquid for study. Instead of only being able to study one variable per flight, the ability to make adjustments to the experiment on orbit increased the amount of data that was gathered, thereby m a k i n g the most of the available crew time. By studying thermocapillary flow in a low-gravity environment, researchers are discovering ways to control the mixing of liquid materials for a variety of applications on Earth.

M u l t i u s e r R e s o u r c e s — Glovebox designers were t h i n k i n g about the needs of a broad range of experiments d u r i n g its development. Built-in resources such as power, lighting, ventilation, a n d i n s t r u m e n t s for data a n d video collection and downlinking mean that researchers don't need to be concerned about devising and developing these tools for their individual experiments, thereby cutting down on the time it takes to prepare an experiment for flight. Experiments in protein crystal growth have made use of the available data and video interface drawers and power supply for imaging the growing protein crystals and providing the proper temperature and humidity conditions for optimal g r o w t h . Research on protein crystals in microgravity often yields larger and more uniform crystals than can be g r o w n on Earth. Space-grown crystals are helping researchers gain a better understanding of the relationship between protein structure and function in the h u m a n body.

Needles (top left) dispensed a drop of methanol onto a silicon carbide fiber. Once the drop reached a predetermined size, it was ignited, and its burning rate and extinction diameter were measured. Glovebox investigations helped researchers perfect the tools for dispensing and positioning a drop of fuel in low gravity.

Plans for the ISS NASA's success in partnering with E S A on previous gloveboxes has lead to the design and development of a n e w facility, called the Microgravity Science Glovebox (MSG), for investigations on the International Space Station (ISS). Experience gained by operating successful glovebox prog r a m s on the space shuttle and Mir is proving to be valuable for d e t e r m i n i n g the science requirements for the M S G . T h e ' n e w facility will have a larger w o r k volume, larger ports, increased power and lighting for investigations, and enhancements to its data and video collection, uplinking and d o w n l i n k i n g , and remote c o m m a n d systems.

For More Information http://microgravity, nasa.gov/Glov, html

Aided by the ability to optimize growth conditions inside the glovebox, crystals of horse serum albumin grew large enough for structural analysis by X-ray diffraction. Serum albumin regulates blood pressure and transports ions, metabolites, and drugs.

Microgravity Research Program Office G e o r g e C . IVIarshall S p a c e F l i g h t C e n t e r Huntsville, A l a b a m a FS-1999-03-36-MSFC