Category : Science and Education
Archive   : STS-37.ZIP
Filename : WATCH.TXT

STS-37 Mission Watch


STS-37 Gamma Ray Observatory

The second of NASA's Great Observatories, the Gamma Ray
Observatory or GRO, will be deployed into space by the crew of
the Space Shuttle Atlantis on the STS-37 mission this spring.
The first of these observatories was the Hubble Space Telescope
that was launched in 1990. At 15,655 kilograms, the GRO will
be the heaviest payload ever deployed by the Shuttle's remote
manipulator system arm (RMS). On flight day three, the GRO
will be lifted out of Atlantis's payload bay with the orbiter's
remote manipulator system arm. Following the unfolding of the
spacecraft's solar arrays and high-gain antenna and the
charging of its batteries, the GRO will be released. Atlantis
will then move slowly away by firing its reaction control
system engines. In addition to deploying the spacecraft, the
STS-37 crew, during its five-day mission, will be conducting a
variety of middeck scientific experiments and the first
extravehicular activity (EVA) in five and a half years.

Gamma Ray Observatory

Astronomers around the world are eager for the launch of the
GRO because the spacecraft will help them to fill in missing
pieces in our view of the universe about us. Outer space is
filled with electromagnetic radiation that tells the story of
the birth and death of stars and galaxies. Only a small
portion of that radiation is visible to our eyes. The rest can
be detected only with special instruments. Gamma rays are one
form of invisible radiation. In a chart of the electromagnetic
spectrum, gamma rays fall at the far right end after visible
light, ultraviolet light, and X rays. Gamma rays have very
short wavelengths and are extremely energetic, but most of them
do not penetrate Earth's atmosphere. The only way for
astronomers to view these waves is to send instruments into
space.

The GRO is a complex spacecraft fitted with four different
gamma ray detectors, each of which concentrates on different
but overlapping energy ranges. The instruments are the largest
of their kind that have ever flown in space. This is important
because gamma rays can only be detected when they interact with
matter. The bigger the masses of the detectors, the greater
the number of gamma rays they can detect. The process for
gamma ray detection is similar to the way fluorescent paints
convert ultraviolet light to visible light. When gamma rays
interact with crystals, liquids, and other materials, they
produce flashes of light that are recorded by electronic
sensors. Astronomers can determine how energetic a particular
ray is from the intensity of the flash. The brighter the flash
of light from the interaction, the higher the energy of the
ray.

The four different kinds of gamma ray detectors on the GRO are
the Burst and Transient Source Experiment (BATSE), Oriented
Scintillation Spectrometer Experiment (OSSE), Imaging Compton
Telescope (COMPTEL), and the Energetic Gamma Ray Experiment
Telescope (EGRET). The BATSE experiment consists of eight
detectors placed on the corners of the spacecraft. The other
experiments consist of single devices.

Astronomers will compare the intensities and directions of
gamma ray interactions with the GRO's detectors to learn about
the most powerful celestial bodies and events in the universe.
The GRO will help astronomers address fundamental questions
about the process of energy transfer in the universe and
provide a new understanding of the processes at work in
supernovas, neutron stars, pulsars, and quasars.

EVA

Extravehicular activity, or spacewalking, has been an essential
element of many NASA manned space missions. EVA has been used
for exploration of the Moon's surface, repair of the Skylab
space station, and satellite retrieval and repair. EVAs are
planned for the assembly and operation of Space Station
Freedom. In preparation for future EVAs, two of the STS-37 crew
members will don Shuttle space suits and exit Atlantis's
airlock into the payload bay on flight day four. They will be
experimenting with new apparatus and techniques for moving
equipment and themselves about and for doing work in space.


The EDFE (EVA Development Flight Experiment) consists of three
elements: (1) flight-testing various methods of getting around
large space structures; (2) learning how much force an EVA
astronaut can exert to rotate a bolt or move a piece of
equipment; and (3) finding the most efficient ways to use the
Shuttle's RMS to aid an EVA astronaut in moving to work sites
and installing equipment. Getting around large space
structures ranges from using simple methods like pulling
hand-over-hand along a rope to complex methods involving
mechanical or electrical devices. Once in the payload bay, the
EVA crew will assemble a 15-meter-long track. Various carts
will be tested on the track. One cart operates somewhat like a
railroad hand-car and transforms astronaut movements of a push
bar to mechanical thrust. A second cart is propelled by an
electric motor that gets electricity from a generator powered
by hand cranks. Additional translation experiments will
involve using a rope reel device and hand rails for
translation.

Secondary Experiments

Built into the STS-37 schedule around GRO deployment and
extravehicular activities are a variety of materials and
systems experiments. The Protein Crystal Growth II (PCG II)
experiment is a continuation of an earlier experiment flown on
the Space Shuttle. Researchers are hoping the microgravity
environment of the Space Shuttle will permit the experiment to
grow large protein crystals with few, if any, of the
distortions that occur in the one-gravity environment on Earth.
When returned to Earth, the atomic structures of the crystals
will be examined to help scientists develop more effective
medicines with fewer side effects.

The Bioserve Instrumentation Technology Associates Material
Dispersion Apparatus (BIMDA) is a commercial experiment that
will demonstrate technology for biomedical and fluid science
experiments. BIMDA has four material dispersion laboratories
that can automatically mix as many as 182 samples in 35
separate biomedical and chemical experiments developed by 22
researchers. The BIMDA apparatus fits in the space of a single
locker on Atlantis's middeck. Because of its compact size and
potential for automatic operation, the developers of the
apparatus believe it will make microgravity research more
affordable to scientists and small companies.

Other experiments include the Space Station Heat Pipe Advanced
Radiator Element II (SHARE II) middeck experiment and the
Radiation Monitoring Equipment III (RME III). The SHARE II
middeck experiment will investigate heat pipe technology for
transferring heat from one location to another. A heat pipe is
a sealed tube with a fluid inside. The pipe absorbs heat on
one end and transports it via the fluid to the other end, where
it is radiated. Heat pipes are extremely efficient
heat-transfer devices and the experiment seeks to develop
future space station versions of the pipes that will be equally
efficient in the microgravity environment in space. The RME
III experiment is a continuation of earlier Shuttle experiments
aimed at a better understanding of the nature of radiation
environment in Earth orbit.

The Air Force Maui Optical Site Calibration Test (AMOS) does
not involve any experimental apparatus on Atlantis. As Atlantis
passes within optical range of the Air Force Maui site,
Atlantis will fire some of its reaction control system engines
to initiate brief rolling motions. Instruments at the optical
site will observe Atlantis and compare its appearance from the
ground with its known orientations in space.

The Shuttle Amateur Radio Experiment II (SAREX II) is being
flown for the American Radio Relay League, the Amateur
Satellite Corporation, and NASA Headquarters' Educational
Affairs Division. In preparation for the experiment, all five
STS-37 crew members earned amateur radio licenses. When time
permits, they will use a VHF radio transmitter and receiver to
contact ham radio operators around the world with radio.
During the flight, the crew will make a special effort to use
SAREX to make contact with students in several schools across
the United States.


STS-37 Quick Facts

Crew: Steven R. Nagel - Col., USN - Commander
Kenneth D. Cameron - Lt. Col., USMC - Pilot
Jerry L. Ross - Lt. Col., USAF - Mission Specialist
Jay Apt - Ph.D. - Mission Specialist
Linda M. Godwin - Ph.D. - Mission Specialist

Vehicle: OV-104 Atlantis
Mission duration: 5 days
Orbital inclination: 28 degrees
Orbital altitude: 450 km
Primary payload: GRO - Gamma Ray Observatory
Secondary payloads EDFE- EVA Development Flight
Experiment and experiments: PCG II - Protein Crystal
Growth II RME III - Radiation Monitoring Equipment III
AMOS - Air Force Maui Optical Site Calibration Test
SAREX II - Shuttle Amateur Radio Experiment II BIMDA -
Bioserve Instrumentation Technology Associates
Materials Dispersion Apparatus SHARE II Middeck - Space
Station Heat Pipe Advanced Radiator Element II






Classroom Activities and Questions

1. The entire progress of the mission from launch to landing
can be observed on television if your school has a satellite
dish. Direct the dish to the SATCOM F2R satellite at 72
degrees west longitude. Tune into NASA Select, transponder 13,
3960 megahertz. If your school does not have a satellite dish,
but does have a cable television hookup, call your local cable
operators and request they receive NASA Select and distribute
it on one of their channels or tape it for your use. Check
local news services for updates on Atlantis's liftoff or call
the NASA Kennedy Space Center at 407-867-2525 for a recorded
message.

2. Contact the American Radio Relay League for the name of a
local amateur radio operator who might be willing to provide a
SAREX demonstration for your classroom. The league is
coordinating a number of educational activities related to the
experiment. American Radio Relay League 225 Main Street
Newington, CT 06111

3. Examine an electromagnetic spectrum diagram for the
position of gamma rays. Diagrams are found in many astronomy
and physics textbooks and encyclopedias. Research how gamma
rays are produced and detected and their significance to
astronomy.

4. Use a skateboard for classroom tests of EVA translation.
Have a student stand on the skateboard and try to move across
the room by pulling on a rope tied to opposite ends. Ask the
students to invent mechanical and electrical devices that would
aid an astronaut in moving about a space station.

5. Why are scientists interested in growing perfect crystals
in space?

6. Check astronomy magazines for articles about NASA's Great
Observatories, including the Hubble Space Telescope, the Gamma
Ray Observatory, the Advanced X-Ray Astrophysics Facility
(planned), and the Space Infrared Telescope Facility (planned).

References

NASA (1989), "Amateur Radio in Space," NASA Educational Briefs
for the classroom, EB 89-1, National Aeronautics and Space
Administration, Washington, D.C..

NASA, "Gamma-Ray Observatory: Exploring the Mysteries of Time,"
NASA Goddard Space Flight Center, Greenbelt, MD.

NASA, The Gamma-Ray Observatory, NP-124, National Aeronautics
and Space Administration, Washington, D.C.

Smith, D.H. (May 1990), "Seeking the Origins of Cosmic Rays,"
Sky and Telescope, 479-484.

Smith, B.A. (May 5, 1990), "Gamma-Ray Observatory to Study
Celestial Forces that Shaped the

Universe," Aviation Week and Space Technology, 70-73.

White, R. (1991), "SAREX: Sharing the Exploration of Our World
and Beyond," QST, 75:2,44-46.