The World of Computer Software/World_Of_Computer_Software-02-385-Vol-1of3.iso/s/sts-54.zip/STS54.TXT

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SHUTTLE MISSION STS-54



NASA PRESS KIT

JANUARY 1993


DIFFUSE X-RAY SPECTROMETER

TRACKING AND DATA RELAY SATELLITE


PUBLIC AFFAIRS CONTACTS

NASA Headquarters

Office of Space Flight/Office of Space Systems Development
Mark Hess/Jim Cast/Ed Campion
(Phone:  [phone])

Office of Space Science and Applications
Paula Cleggett-Haleim/Mike Braukus/Brian Dunbar
(Phone:  [phone])

Office of Space Communications / Office of Safety & Mission Quality
Dwayne Brown
(Phone:  [phone])

Office of Advanced Concepts and Technology
Barbara Selby
(Phone:  [phone])

Office of Aeronautics
Drucella Andersen/Les Dorr
(Phone:  [phone])

Ames Research Center                            Langley Research Center
Jane Hutchison                                  Jean Drummond Clough
(Phone:  [phone])                          (Phone:  [phone])

Dryden Flight Research Facility                 Lewis Research Center
Nancy Lovato                                    Mary Ann Peto
(Phone:  [phone])                          (Phone:  [phone])

Goddard Space Flight Center                     Marshall Space Flight Center
Dolores Beasley                                 June Malone
(Phone:  [phone])                          (Phone:  [phone])

Jet Propulsion Laboratory                       Stennis Space Center
James Wilson                                    Myron Webb
(Phone:  [phone])                          (Phone:  [phone])

Johnson Space Center                            Wallops Flight Center
James Hartsfield                                Keith Koehler
(Phone:  [phone])                          (Phone:  [phone])

Kennedy Space Center
George Diller
(Phone:  [phone])



CONTENTS

GENERAL BACKGROUND
     Media Services
Information............................................................. 01
     Quick-Look
Facts...........................................................
     Summary
Timeling...........................................................
     Payload and Vehicle
Weights................................................................  04
     STS-54 Orbital Events
Summary................................................................  04
     Space Shuttle Abort
Modes................................................................... 05
     Prelaunch
Processing.......................................................

CARGO BAY PAYLOADS & ACTIVITIES
     Tracking Data Relay Satellite-F (TDRS-F)........................... 06
     Inertial Upper Stage (IUS)......................................... 14
     Diffuse X-ray Spectrometer (DXS)................................... 19
     Extravehicular Activities for STS-54............................... 23

MIDDECK PAYLOADS
     Chromosomes Experiment (CHROMEX)................................... 23
     Commercial Generic Bioprocessing Apparatus......................... 25
     Physiological & Anatomical Rodent Experiment (PARE)................ 32
     Solid Surface Combustion Experiment (SSCE)......................... 34
     Application Specific Preprogrammed Experiment Culture
          System Physics of Toys (ASPEC)................................ 36

CREW BIOGRAPHIES & MISSION MANAGEMENT
     STS-54 Crew Biographies............................................
     Mission Management for STS-54......................................    39
     Previous Shuttle Flights...........................................






MEDIA SERVICES INFORMATION


NASA Select Television Transmission

        NASA Select television is available on Satcom F-2R,
Transponder 13, located at 72 degrees west longitude, frequency 3960.0
MHz, audio 6.8 MHz.

        The schedule for television transmissions from the orbiter and
mission briefings will be available during the mission at Kennedy Space
Center, Fla; Marshall Space Flight Center, Huntsville, Ala.; Ames-
Dryden Flight Research Facility, Edwards, Calif.; Johnson Space Center,
Houston, and NASA Headquarters, Washington, D.C.  The television
schedule will be updated to reflect changes dictated by mission
operations.

        Television schedules also may be obtained by calling COMSTOR
713/483-5817.  COMSTOR is a computer data-base service requiring the
use of a telephone modem.  A voice update of the television schedule is
updated daily at noon Eastern time.

Status Reports

        Status reports on countdown and mission progress, on-orbit
activities and landing operations will be produced by the appropriate
NASA newscenter.

Briefings

        A mission press briefing schedule will be issued prior to
launch.  During the mission, status briefings by a flight director or
mission operations representative and when appropriate, the science
team will occur at least once per day.  The updated NASA Select
television schedule will indicate when mission briefings are planned.


STS-54 QUICK LOOK


Launch Date/Site:       Jan. 13, 1993/Kennedy Space Center, Fla. -- Pad 39B
Launch Time:            8:52 a.m. EST
Orbiter:                Endeavour (OV-105) - 3rd Flight
Orbit/Inclination:      160 nm/28.45 degrees
Mission Duration:       5 days, 0 hours, 23 minutes, 32 seconds
Landing Time/Date:      8:34 a.m. EST, Jan. 19, 1993
Primary Landing Site:   Kennedy Space Center, Fla.
Abort Landing Sites     Return To Launch Site Abort:  KSC, Fla
                        TransAtlantic Abort Landing:   Banjul, The Gambia
                        Ben Guerir, Morroco
                        Moron, Spain
Abort-Once-Around:      Edwards AFB, Calif.
                        KSC/White Sands

Crew:                   John Casper - Commander
                        Don McMonagle - Pilot
                        Mario Runco, Jr. - MS1 (EV2)
                        Greg Harbaugh - MS2 (EV1)
                        Susan Helms - MS3

Cargo Bay Payloads:     Tracking and Data Relay Satellite-F
                        Diffuse X-ray Spectrometer

Middeck Payloads:       Commercial Generic Bioprocessing Apparatus
                        Chromosome and Plant Cell Division in Space Experiment
                        Physiological and Anatomical Rodent Experiment
                        Space Acceleration Measurement System
                        Solid Surface Combustion Experiment


STS-54 SUMMARY TIMELINE

Flight Day One

Launch/post insertion
TDRS-F deploy (nominal deploy is 6 hours, 13 minutes MET)
Separation burn (178 n.m. x 162 n.m. orbit)
DXS activation

Flight Day Two

DXS operations
Circularization burn (162 n.m. x 162 n.m. orbit)
CGBA operations
Medical DSOs

Flight Day Three

DXS operations
CGBA operations
SSCE operations
CHROMEX/PARE operations

Flight Day Four

DXS operations
CGBA operations
Medical DSOs
CHROMEX/PARE operations

Flight Day Five

DXS operations
EVA

Flight Day Six

Flight Control Systems checkout
Cabin stow

Flight Day Seven

Deorbit Preparation
Deorbit Burn
Entry
Landing


STS-54 VEHICLE AND PAYLOAD WEIGHTS

Vehicle/Payload                                            Pounds

Orbiter (Endeavour) Empty and three SSMEs                 173,174
Tracking and Data Relay Satellite-F (TDRS-F)                5,586
Two-Stage Inertial Upper Stage (IUS)                       32,670
Diffuse X-ray Spectrometer (DXS)                            2,625
Medical Detailed Supplementary Objectives (DSOs)               34
Total Vehicle at Solid Rocket Booster Ignition          4,525,222
Orbiter Landing Weight                                    205,000


STS-54 ORBITAL EVENTS SUMMARY

Event           Elapsed time            Velocity change         Orbit (nm)

Launch          0:00:00:00                      N/A             N/A
OMS-2           0:00:42:00                      221 fps         163x160
TDRS deploy     0:06:13:00                      N/A             163 x 160
Sep 1           0:06:14:00                      2.2 fps         162 x 160
OMS-3           0:06:28:00                      31 fps          178 x 162
OMS-4           1:02:09:00                      28 fps          162 x 161
Deorbit         5:22:32:00                      306 fps         N/A
Landing         5:23:32:00                      N/A             N/A



SPACE SHUTTLE ABORT MODES

        Space Shuttle launch abort philosophy aims toward a safe and
intact recovery of the flight crew, orbiter and its payload.  Abort modes
include:

        * Abort-To-Orbit (ATO) -- Partial loss of main engine thrust
late enough to permit reaching a minimal 105-nautical mile orbit with
orbital maneuvering system engines.

        * Abort-Once-Around (AOA) -- Earlier main engine shutdown
with the capability to allow one orbit around before landing at either
Edwards Air Force Base, Calif., White Sands Space Harbor, N.M., or the
Shuttle Landing Facility (SLF) at the Kennedy Space Center, Fla.

        * Trans-Atlantic Abort Landing (TAL) -- Loss of one or more
main engines midway through powered flight would force a landing at
either Banjul, The Gambia; Ben Guerir, Morocco; or Moron, Spain.

        * Return-To-Launch-Site (RTLS) -- Early shutdown of one or
more engines, without enough energy to reach Banjul, would result in a
pitch around and thrust back toward KSC until within gliding distance
of the Shuttle Landing Facility.

        STS-54 contingency landing sites are Edwards Air Force Base,
the Kennedy Space Center, White Sands Space Harbor, Banjul, Ben Guerir
and Moron.  STS-54 PRELAUNCH PROCESSING

     Processing of Endeavour began with its landing at KSC after the
STS-47 mission.  It was deserviced from its previous flight and
prepared for the upcoming STS-54 mission.  Endeavour spent a total of
64 calendar days in the Orbiter Processing Facility.

     The Space Shuttle Endeavour was rolled out of the Vehicle
Assembly Building for Pad 39-B on Dec. 3.  The TDRS-F/IUS-13 was
installed into the orbiter's payload bay the following day.

     A standard 43-hour launch countdown is scheduled to begin 3
days prior to launch.  During the countdown, the orbiter's fuel cell
storage tanks and all orbiter systems will be prepared for flight.

     About 9 hours before launch, the external tank will be filled with
its flight load of a half million gallons of liquid oxygen and liquid
hydrogen propellants.  About 2 and one-half hours before liftoff, the
flight crew will begin taking their assigned seats in the crew cabin.

     Endeavour's end-of-mission landing is planned at Kennedy Space
Center's Shuttle Landing Facility.  Endeavour's next flight, STS-57,
targeted for May 1993, is a planned 7-day mission which will involve
the SPACEHAB-1 payload and the retrieval of the EURECA satellite.


TRACKING DATA RELAY SATELLITE-F (TDRS-F)

History

     The Tracking and Data Relay Satellite System (TDRSS) is a space-
based network that provides communications, tracking, telemetry, data
acquisition and command services essential to the Space Shuttle and
low-Earth orbital spacecraft missions.  All Shuttle missions and nearly
all NASA spacecraft in Earth orbit require TDRSS's support capabilities
for mission success.

     The TDRSS was initiated following studies in the early 1970s
which showed that a system of telecommunications satellites, operated
from a single ground station, could better meet the requirements of
NASA missions.  In addition, the system was seen as a means of halting
the spiralling costs of upgrading and operating a network of tracking
and communications ground stations located around the world.

     The TDRSS has enabled NASA to cut telecommunications costs by
as much as 60 percent while increased data acquisition and
communications with Earth-orbital spacecraft from 15 to 85 percent --
and in some cases to 100 percent -- depending on a spacecraft's orbital
position.

     In addition to the Shuttle, TDRSS customers include the Compton
Gamma Ray Observatory, Upper Atmosphere Research Satellite, Hubble
Space Telescope, Cosmic Background Explorer, Extreme Utraviolet
Explorer, TOPEX-Poseidon, both Landsat spacecrafts and other non- NASA
missions.  Among future TDRSS-dependent missions are Space Station
Freedom (SSF) and the Earth Observation System (EOS).  It is estimated
that over $70 billion in space missions through the end of this decade
are TDRSS-dependent.

     The TDRSS consists of two major elements:  A constellation of
three geosynchronous satellites -- two operational and one in ready
reserve -- and a ground terminal located at White Sands, N.M.  A second
TDRSS ground terminal is under development to eliminate a critical
single point of failure.

     To meet the growing demand for communications capabilities for
future missions, such as SSF and the EOS, increased TDRSS capacity will
be required to meet these additional mission requirements.

Current Status

     The Tracking and Data Relay Satellite (TDRS-6) is the sixth in a
series of communications spacecraft planned for the TDRSS.

     TDRS-1, has exceeded its design life of 7 years and is continuing
to provide limited services. TDRS-2 was lost in the Challenger
accident.  TDRSs 3-5 are operating, but only two are fully functional.
In the event of a malfunction of one of these fully operational TDRS,
the absence of a third fully operational satellite in ready reserve
would severely impact orbiting customers for nearly a year before an
emergency replenishment launch could be conducted.

     The successful launch and checkout of TDRS-6 will give NASA the
essential requirement of having two fully operational satellites and a
fully operational ready reserve capability. This will assure that NASA
communications, telemetry and data acquisition capabilities required by
space missions will not be jeopardized.

     Following the successful launch and checkout of TDRS-6, the
TDRSS constellation will be reconfigured.  Because of the flexible
capability of the TDRSS, one TDRS spacecraft will provide service to
the Compton Gamma Ray Observatory (GRO), including realtime
transmission of scientific data.  This is required because of a problem
with the GRO's tape recorders.  To accommodate this activity, NASA will
operate TDRS-1 thru an existing station at Tidbinbilla, Australia,
moving TDRS-1 from 171 degrees west longitude to 85 degrees east
longitude (over the Indian Ocean south of Ceylon).

     Data from GRO will be relayed to the ground terminal at White
Sands, via an Intelsat satellite.  From White Sands, the data will be
sent to the Goddard Space Flight Center, Greenbelt, Md.  Control of the
TDRS spacecraft will remain at White Sands.


TDRS SPACECRAFT LAUNCH AND OPERATIONAL STATUS

Spacecraft              Mission                    Status

TDRS-1                  STS-6 April 5, 1983        Partially functional
TDRS-2                  STS-51L January 1986
TDRS-3                  STS-26 Sept. 29, 1988      Partially functional
TDRS-4                  STS-29 March 13, 1989      Fully functional
TDRS-5                  STS-43 August 2, 1991      Fully functional


TDRS SPACECRAFT CURRENT AND RECONFIGURED POSITION


Current Position

TDRS-1   171 degrees west (East of Gilbert Islands and South of Hawaii).
TDRS-3   62 degrees west
TDRS-4   41 degrees west (over the Atlantic Ocean off Brazil)
TDRS-5   174 degrees west (East of Gilbert Islands and South of Hawaii).


Reconfigured Position after TDRS-F (6 on orbit)

TDRS-1   85 degrees east
TDRS-3   171 degrees west
TDRS-4   41 degrees west
TDRS-5   174 degrees west
TDRS-6   62 degrees west


Deployment Sequence

     TDRS-6 will be deployed from Endeavour cargo bay approximately 6
hours after launch on orbit 5 over the Pacific Ocean north of Hawaii.
Injection burn to geostationary orbit will be initiated at 77 degrees
east longitude (Indian Ocean, south of India), placing the satellite in
orbit at 178 degrees west longitude (over the Pacific near the Gilbert
Islands).

     The STS-54 crew elevates the Inertial Upper Stage/TDRS (IUS/TDRS)
to 29 degrees in the payload bay for preliminary tests and then raises
it to 58 degrees for deployment.  A spring-loaded ejection system is
used for deploying the IUS/TDRS.

     The first burn of the IUS booster will take place 1 hour after
deployment or about 7 hours after STS-54 launch.  The IUS second and
final burn, to circularize the orbit, will take place 5.5 hours after
the first burn, approximately 12.5 hours into the mission.  Separation
of the booster and satellite will occur at 13 hours after launch.

     Upon reaching geostationary orbit, the deployment of TDRS
appendages and antennas is started.  The total time required for the
deployment sequence is 8-9 hours:

        1 - Deploy solar arrays.
        2 - Deploy space-ground link boom.
        3 - Deploy C-band boom.
        4 - Separation of IUS and TDRS.
        5 - Release single access booms.
        6 - Position single access antennas.
        7 - Open single access antennas.

     During steps 5, 6 and 7, Earth acquisition is taking place
concurrently.

     TDRS is three-axis stabilized with the multiple access body, fixed
antennas pointing constantly at the Earth while the solar arrays track
the sun.

Communication System

     TDRS satellites do not process customer traffic in either
direction.  Rather, they operate as "bent pipe" repeaters, relaying
signals and data between the user spacecraft and the ground terminal
and vice versa.

     Nominally, the TDRSS is intended to meet the requirements of up
to 24 customer spacecraft, including the Space Shuttle,
simultaneously.  It provides two types of service:  multiple access
which can relay data from as many as 20 low data rate (100 bits per
second to 50 kilobits per second) customer satellites simultaneously
and single access antennas which provide two high data rate channels to
300 megabits per second from both the east and west locations.

ART -- TDRS Deployment Sequence

ART -- TDRS On-orbit Configuration

ART -- Five TDRS - 1993



     The White Sands Ground Terminal (WSGT) provides a location with a
clear line-of-sight to the TDRSs and a place where rain conditions have
limited interference with the availability of the Ku-band uplink and
downlink channels. The WSGT is operated for NASA by GTE Government
Systems Corp., Needham Heights, Mass.

     Co-located at White Sands is the NASA Ground Terminal operated
by Bendix Field Engineering Corp., Columbia, Md.  This terminal
provides the interface between WSGT and other primary network elements
located at NASA's Goddard Space Flight Center, Md.

     Facilities at GSFC include the Network Control Center (NCC)
which provides system scheduling and is the focal point for NASA
communications and the WSGT and TDRSS users; the Flight Dynamics
Facility which provides the network with antenna pointing information
for user spacecraft and the TDRSs and the NASA Communications Network
(NASCOM) which provides the common carrier interface through Earth
terminals at Goddard, White Sands and the Johnson Space Center,
Houston.

     The NCC console operators monitor network performances, schedule
emergency interfaces, isolate faults in the system, account for system
use, test the system and conduct simulations.

     The user services available from the space network are provided
through NASCOM, a global system providing operational communications
support to all NASA projects.  NASCOM offers voice, data and teletype
links with the space network, the Ground Spaceflight Tracking and Data
Network and the user spacecraft control centers.

     NASA's Office of Space Communications, Washington, D.C., has
overall management responsibility of these tracking, data acquisition
and communications facilities.

TDRS Components

     TDRSs are composed of three distinct modules -- an equipment
module, a communications payload module and an antenna module.  The
modular design reduces the cost of individual design and construction
efforts that, in turn, lower the cost of each satellite.

     The equipment module housing the subsystems that operate the
satellite is located in the lower hexagon of the spacecraft.  The
attitude control subsystem stabilizes the satellite to provide accurate
antenna pointing and proper orientation of the solar panels to the
sun.  The electrical power subsystems consists of two solar panels that
provide a 10-year power supply of approximately 1,700 watts.  The
thermal control subsystem consists of surface coatings and controlled
electric heaters.

     The payload module is composed of the electronic equipment
required to provide communications between the user spacecraft and the
ground.  The receivers and transmitters for single access services are
mounted in compartments on the back of the single-access antennas.

     The antenna module is composed of seven antenna systems:  two
single-access, the multiple access array, space-to-ground link and the
S-band omni for satellite health and housekeeping.  Commercial K-band
and C-band antennas round out the complement.

     For single-access service, the TDRSs have dual-feed S-band, Ku-
band parabolic (umbrella-like) antennas.  These antennas are free to be
positioned in two axis, directing the radio beam to orbiting user
spacecraft below.  These antennas primarily relay communications to and
from user spacecraft.  The high data rates provided by these antennas
are available to users on a time-shared basis.  Each antenna is capable
of supporting two user spacecraft services simultaneously -- one at
S-band and one at Ku- band- provided both users are within the beam
width of the antenna.

     The multiple access antenna array is hard-mounted in one
position on the surface of the antenna module facing the Earth  Another
antenna, a 6.5-foot (2-meter) parabolic reflector, provides the prime
link for relaying transmissions to and from the ground terminal at
Ku-band.

Project Support

     TRW Space & Electronics Group, Redondo Beach, Calif., is the
prime spacecraft contractor.  Ground operations at the White Sands
complex are conducted by GTE Government Systems Corp., Needham Heights,
Mass., and Bendix Field Engineering Corp., Columbia, Md.

INERTIAL UPPER STAGE (IUS)

     The Inertial Upper Stage (IUS) will be used with the Space Shuttle
to transport NASA's sixth Tracking and Data Relay Satellite (TDRS-F) to
geosynchronous orbit, some 22,300 statute miles (35,880 km) from
Earth.

Background

     The IUS was originally designed as a temporary stand-in for a
reusable space tug, and the IUS was named the Interim Upper Stage.  The
word "Inertial" (signifying the guidance technique) later replaced
"Interim" when it was determined that the IUS would be needed through
the 1990's.  In addition to the TDRS missions, the IUS was utilized for
the Magellan, Galileo and Ulysses planetary missions.

     The IUS was developed and built under contract to the Air Force
Systems Command's Space Division.  The Space Division is executive
agent for all Department of Defense activities pertaining to the Space
Shuttle system and provides the IUS to NASA for Space Shuttle use.
Boeing Aerospace Company, Seattle, was selected in August 1976 to build
the IUS.


Specifications

     IUS-13, to be used on mission STS-54, is a two-stage rocket.  Each
stage has a solid rocket motor, preferred over liquid-fueled engines
for their relative simplicity, high reliability, low cost and safety.

     The IUS is 17 feet (5.18 meters) long and 9.25 feet (2.8 m) in
diameter.  It consists of an aft skirt; an aft stage solid rocket motor
containing 21,400 pounds (9,707 kg) of propellant generating
approximately 42,000 pounds (188,496 newtons) of thrust; an interstage;
a forward stage solid rocket motor with 6,000 pounds (2,722 kg) of
propellant generating approximately 18,000 pounds (80,784 newtons) of
thrust and an equipment support section.

     The equipment support section contains the avionics which
provide guidance, navigation, control, telemetry, command and data
management, reaction control and electrical power.  All
mission-critical components of the avionics system, along with thrust
vector actuators, reaction control thrusters, motor igniter and
pyrotechnic stage separation equipment are redundant to assure
reliability of better than 98 percent.

Airborne Support Equipment

     The IUS Airborne Support Equipment (ASE) is the mechanical,
avionics, and structural equipment located in the orbiter.  The ASE
supports the IUS and the TDRS-F in the orbiter payload bay and elevates
the IUS/TDRS for final checkout and deployment from the orbiter.

     The IUS ASE consists of the structure, aft tilt frame actuator,
batteries, electronics and cabling to support the IUS/TDRS
combination.  These ASE subsystems enable the deployment of the
combined vehicle; provide, distribute and/or control electrical power
to the IUS and satellite and serve as communication conduits between
the IUS and/or satellite and the orbiter.

IUS Structure

     The IUS structure is capable of supporting the loads generated
internally and also by the cantilevered spacecraft during orbiter
operations and the IUS free flight.  In addition, the structure
physically supports all the equipment and solid rocket motors within
the IUS, and provides the mechanisms for IUS stage separation.  The
major structural assemblies of the two-stage IUS are the equipment
support section, interstage and aft skirt.  It is made of aluminum
skin-stringer construction with longerons and ring frames.

Equipment Support Section

     The Equipment Support Section houses the majority of the IUS
avionics.  The top of the equipment support section contains the
spacecraft interface mounting ring and electrical interface connector
segment for mating and integrating the spacecraft with the IUS.
Thermal isolation is provided by a multilayer insulation blanket across
the interface between the IUS and TDRS.

IUS Avionics Subsystems

     The avionics subsystems consist of the telemetry, tracking and
command subsystems; guidance and navigation subsystem; data management;
thrust vector control and electrical power subsystems.  These
subsystems include all electronic and electrical hardware used to
perform all computations, signal conditioning, data processing and
formatting associated with navigation, guidance, control, data and
redundancy management.  The IUS avionics subsystems also provide the
equipment for communications with the orbiter and ground stations as
well as electrical power distribution.

     Attitude control in response to guidance commands is provided
by thrust vectoring during powered flight and by reaction control
thrusters while coasting.

     Attitude is compared with guidance commands to generate error
signals.  During solid motor firing, these commands gimble the IUS's
movable nozzle to provide the desired attitude pitch and yaw control.
The IUS's roll axis thrusters maintain roll control.  While coasting,
the error signals are processed in the computer to generate thruster
commands to maintain the vehicle's altitude or to maneuver the
vehicle.

     The IUS electrical power subsystem consists of avionics batteries,
IUS power distribution units, power transfer unit, utility batteries,
pyrotechnic switching unit, IUS wiring harness and umbilical, and
staging connectors.  The IUS avionics system distributes electrical
power to the IUS/TDRS interface connector for all mission phases from
prelaunch to spacecraft separation.

IUS Solid Rocket Motors

     The IUS uses a large and a small solid rocket motor employing
movable nozzles for thrust vector control.  The nozzles provide up to 4
degrees of steering on the large motor and 7 degrees on the small
motor.  The large motor is the longest thrusting duration solid rocket
motor ever developed for space, with the capability to thrust as long
as 150 seconds.  Mission requirements and constraints (such as weight)
can be met by tailoring the amount of solid propellant carried.

Reaction Control System

     The reaction control system controls the IUS/TDRS's attitude
during coasting; roll control during SRM thrustings and velocity
impulses for accurate orbit injection.

     As a minimum, the IUS includes one reaction control fuel tank
with a capacity of 120 pounds (54.4 kg) of hydrazine.  Production
options are available to add a second or third tank.  IUS-13 will carry
two tanks, each with 120 pounds (54.4 kg) of fuel.

     To avoid spacecraft contamination, the IUS has no forward facing
thrusters.  The reaction control system also provides the velocities
for spacing between several spacecraft deployments and for avoiding
collision or contamination after the spacecraft separates.

IUS-to-Spacecraft Interfaces

     The TDRS spacecraft is physically attached to the IUS at eight
attachment points, providing substantial load-carrying capability while
minimizing the transfer of heat across the connecting points.  Power,
command and data transmission between the two are provided by several
IUS interface connectors.

     In addition, the IUS provides an insulation blanket of multiple
layers of double-aluminized Kapton and polyester net spacers across the
IUS/TDRS interface.  The outer layer of the blanket, facing the TDRS
spacecraft, is a special Teflon-coated fabric called Beta cloth.  The
blankets are vented toward and into the IUS cavity, which in turn is
vented to the orbiter payload bay.  There is no gas flow between the
spacecraft and the IUS.  The thermal blankets are grounded to the IUS
structure to prevent electrostatic charge buildup.

Flight Sequence

     After the orbiter payload bay doors are opened in orbit, the
orbiter will maintain a preselected attitude to keep the payload within
thermal requirements and constraints.

     On-orbit predeployment checkout begins, followed by an IUS
command link check and spacecraft communications command check.
Orbiter trim maneuvers normally are performed at this time.

     Forward payload restraints will be released and the aft frame of
the airborne support equipment will tilt the IUS/TDRS to 29 degrees.
This will extend the TDRS into space just outside the orbiter payload
bay, allowing direct communication with Earth during systems checkout.
The orbiter will then be maneuvered to the deployment attitude.  If a
problem has developed within the spacecraft or IUS, the IUS and its
payload can be restowed.

     Prior to deployment, the spacecraft electrical power source will
be switched from orbiter power to IUS internal power by the orbiter
flight crew.  After verifying that the spacecraft is on IUS internal
power and that all IUS/TDRS predeployment operations have been
successfully completed, a GO/NO-GO decision for IUS/TDRS deployment
will be sent to the crew.

     When the orbiter flight crew is given a GO decision, they will
activate the pyrotechnics that separates the IUS/TDRS umbilical
cables.  The crew will then command the electromechanical tilt actuator
to raise the tilt table to a 58-degree deployment position.

     The orbiter's RCS thrusters will be inhibited and a pyrotechnic
separation device initiated to physically separate the IUS/spacecraft
combination from the tilt table.   Compressed springs provide the force
to jettison the IUS/TDRS from the orbiter payload bay at approximately
0.10 meters (4.2 inches) per second.  The deployment is normally
performed in the shadow of the orbiter or in Earth eclipse.

     The tilt table will be lowered to minus 6 degrees after IUS and its
spacecraft are deployed.  Approximately 19 minutes after IUS/TDRS
deployment, the orbiter's engines will be ignited to move the orbiter
away from the IUS/TDRS.

     At this point, the IUS/TDRS is controlled by the IUS onboard
computers.  Approximately 10 minutes after the IUS/TDRS is ejected from
the orbiter, the IUS onboard computer will send out signals used by the
IUS and/or TDRS to begin mission sequence events.  This signal also
will enable the reaction control system.  All subsequent operations
will be sequenced by the IUS computer, from transfer orbit injection
through spacecraft separation and IUS deactivation.

     After the RCS has been activated, the IUS will maneuver to the
required thermal attitude and perform any required spacecraft thermal
control maneuvers.

     At approximately 45 minutes after ejection from the orbiter, the
pyrotechnic inhibits for the first solid rocket motor will be removed.
The belly of the orbiter has been oriented towards the IUS/TDRS
combination to protect the orbiter windows from the IUS's plume.  The
IUS will recompute the first ignition time and maneuvers necessary to
attain the proper attitude for the first thrusting period.

     When the proper transfer orbit opportunity is reached, the IUS
computer will send the signal to ignite the first stage motor.  This is
expected at approximately 60 minutes after deployment (L+7 hours, 13
minutes).  After firing approximately 146 seconds and prior to reaching
the apogee point of its trajectory, the IUS first stage will expend its
fuel.  While coasting, the IUS will perform any maneuvers needed by
TDRS for thermal protection or communications.  When this is completed,
the IUS first stage and interstage will be separated from the IUS
second stage.

     Approximately 6 hours, 12 minutes after deployment at
approximately L+12:30, the second stage motor will be ignited,
thrusting for about 108 seconds.  After burn is complete, the IUS
stabilizes the TDRS while the solar arrays and two antennas are
deployed.  The IUS second stage will separate and perform a final
collision/contamination avoidance maneuver before deactivating.


DIFFUSE X-RAY SPECTROMETER (DXS)

     The Diffuse X-ray Spectrometer (DXS) addresses a fundamental
question of present-day astrophysics -- what is the origin and nature
of the interstellar medium, the matter that fills the space between
stars?

     The DXS will study the hottest components of the interstellar
medium, gases at temperatures at approximately 1 million degrees
Kelvin, by detecting the x-rays emitted there.  By measuring the gas
temperature and composition, the DXS will provide important clues to
the origin, evolution and physical state of this constituent of the
Milky Way galaxy.

     The hot interstellar medium is one phase in the life cycle of the
material in this galaxy.  By studying this life cycle, the DXS
scientists hope to learn more about the way the mass and energy of the
galaxy are redistributed as it evolves.  A better understanding of the
evolution of the galaxy is one of the steps toward understanding the
nature and evolution of galaxies, which contain most of the visible
matter in the Universe.

     The DXS, developed by the University of Wisconsin, Madison,
consists of two identical instruments, one mounted to each side of the
Shuttle cargo bay.  A DXS instrument consists of a detector, its
associated gas supply and electronics.  Each instrument is mounted to a
200-pound (91-kg) plate, which is attached to the side of the Shuttle
bay.

     These plates are part of the Goddard Space Flight Center's Shuttle
Payload of Opportunity Carrier (SPOC) standard hardware, which is part
of the Hitchhiker carrier system.

     The Hitchhiker system provides real-time communications
between the payload and customers in the Hitchhiker control center at
Goddard Space Flight Center, Greenbelt, Md.  The carrier system is
modular and expandable in accordance with payload requirements.
Hitchhikers were created to provide a quick reaction and low-cost
capability for flying small payloads in the Shuttle payload bay.

DXS Science

     A large percentage of x-rays from space do not originate from
specific objects like stars or galaxies, but from some source that
appears to be distributed over the entire sky.  Astronomers have found
that these emissions fall into two types:  high-energy or "hard" x-rays
that may be the unresolved emissions from a collection of distant
galaxies and low- energy or "soft" x-rays that are not yet well
understood.  DXS will study the latter.

       Because low energy x-rays cannot travel more than a few
hundred light years in interstellar space before they are absorbed,
most of the diffuse soft x-ray background observed must have originated
in the Milky Way galaxy from the vicinity of Earth's solar system.

ART -- DXS Detector Assembly

ART -- DXS Assembly Second View

     The DXS measures the arrival direction and wavelength of
incident low energy x-rays in the wavelength range of 42 to 84
angstroms -- an angstrom is one ten-thousandth of a millimeter.  From
this information, the DXS scientists will be able to determine the
spectrum (brightness at each wavelength) of the diffuse soft x-ray
background from each of several regions of the sky.

     By analyzing these spectral features, scientists can identify the
temperature, the ionization state and the elements which constitute
this plasma.  From these data they can tell whether the plasma is young
and heated in the last 100,000 years or old and heated millions of
years ago.

     Previous experiments were not capable of measuring the
spectrum of the diffuse soft x-ray background.  With its spectral
determination capability, the DXS will make this type of measurement
possible for the first time.

DXS Operations

     Once the Shuttle is on orbit and the payload bay doors are open,
a crew member will activate the experiment.  DXS will be operated from
Goddard's Payload Operations Control Center (POCC).  University of
Wisconsin personnel at Goddard will control and monitor the DXS, and
Goddard personnel will monitor and control the operations of the
Hitchhiker carrier support hardware.

     The DXS instruments will collect x-ray data during approximately
64 orbital nights over 4 flight days.  In the orbit day periods
throughout the mission, the DXS will perform sensor calibrations and
will periodically replenish the detectors' gas supply.  Goddard's
Flight Dynamics Facility and the Spacelab Data Processing Facility will
assist the DXS POCC operations and data processing activities.

     After the Shuttle lands, the DXS instruments will be transported
to the University of Wisconsin for post-flight testing and
calibration.

DXS History

     The DXS investigation was proposed and selected in response to a
1978 announcement of opportunity to conduct scientific investigations
aboard the Space Shuttle.  NASA selected DXS and four other
astrophysics investigations, including three ultraviolet instruments
and one x-ray telescope that flew in December 1990 on the
STS-35/Astro-1 mission.  All have scientific objectives and
requirements that can be accomplished in a 5- 10 day Shuttle mission.

     DXS was originally manifested to fly with the Broad Band X-ray
Telescope (BBXRT) on the second Shuttle High Energy Astrophysics
Laboratory flight.  In the re-manifesting that followed the Challenger
accident, BBXRT flew on Astro-1, and DXS moved to STS-54.


STS-54 EVA TEST OBJECTIVE

     On the fifth day of the STS-54 flight, Mission Specialists Greg
Harbaugh and Mario Runco, Jr., will perform the first in a series of
test spacewalks to be conducted on Shuttle missions during the years
leading up to the construction of Space Station Freedom, scheduled to
begin in early 1996.

     Harbaugh will be designated Extravehicular Crew Member 1 (EV1)
and Runco will be EV2.  Mission Specialist Susan Helms will assist with
the spacewalk from inside Endeavour's cabin as the intravehicular
activity crew member (IV), tracking the progress of Harbaugh and Runco
as they move through various tasks in the cargo bay.

     The spacewalk tests are designed to refine training methods for
future spacewalks, expand the experience of ground controllers,
instructors and astronauts and aid in better understanding the
differences between true weightlessness and the underwater facility
used to train crew members.

      During the STS-54 spacewalk, Runco and Harbaugh will evaluate
how well they adapt to spacewalking, test their abilities to move about
the cargo bay with and without carrying items, test the ability to
climb into a foot restraint without handholds and test their ability to
align a large object in weightlessness.

     The spacewalk is the lowest priority test being performed on STS-
54.  No extra cargo has been added to the flight for the test, and it
will not have any impact on the other payloads aboard Endeavour.

     To simulate carrying a large object, the astronauts will carry one
another:  to evaluate how well large tools can be used, they will work
with a tool already aboard Endeavour designed to manually raise the
tilt table for the Tracking and Data Relay Satellite's Inertial Upper
Stage booster; to simulate how well they can align an object, they will
attempt to place each other into the brackets in Endeavour's airlock
that hold the spacesuit backpacks when not in use.

     Flight controllers expect many of these tasks to be awkward for
the spacewalkers, and finding out just how difficult they will be is
one goal of the tests. Information from this spacewalk test will be
combined with information from many more that will follow to refine the
understanding of difficulties involved with spacewalk work.

DEVELOPMENTAL AND PHYSIOLOGICAL PROCESSES
INFLUENCING SEED PRODUCTION IN MICROGRAVITY (CHROMEX-4)

Principal Investigator Dr. Mary Musgrave, Louisiana State University

     CHROMEX-4 is designed to gain an understanding of the
reproductive abnormalities which apparently occur in plants exposed to
microgravity, and to determine whether changes in developmental
processes may be due to spaceflight conditions, especially
microgravity.  This experiment also will help understanding how gravity
influences fertilization and development on Earth.

     To date, only a few studies have been conducted on developing
seeds in space, and they all showed very poor seed production.  NASA
would like to use plants as a source of food and atmospheric cleansing
for astronauts staying in space for extended periods of time.  Seed
production is vital if crops like wheat and rice are to be utilized for
food.

     The effects of microgravity on the seed production of Arabidopsis
thaliana will be studied.  Arabidopsis thaliana is a small, cress-type
plant with white flowers.  Its small size, small genome and short life
cycle (45 days) make it ideal for gene mapping studies.  It was chosen
because it is small enough to fit in the flight hardware, and its rapid
life cycle and numerous flowers will ensure that a maximum number of
reproductive stages can be observed in a limited number of plants.
Arabidopsis seeds will be planted preflight so that 14-day-old plants,
capable of producing seeds, can be flown.

     These plants will be flown inside the Plant Growth Unit (PGU), a
closed system that provides day/night lighting located in the orbiter
middeck.  The PGU will hold six Plant Growth Chambers (PGC's), each of
which will contain six plants.  The PGC's provide structural and
nutritional support to the plants while on orbit.

     The PGU replaces one standard middeck locker and requires 28
volts of power from the orbiter.  This hardware provides lighting,
limited temperature control and data acquisition for post-flight
analysis.  The PGU has previously flown on STS-3, -51F, -29 and -41.

     Following the flight, the flowers and developing seeds will be
preserved and their structures will be subjected to gross morphological
and histological analysis to determine the locations and life cycle
stages of reproductive abnormality.  These structures will be examined
in detail by electron-microscopy.

     The remaining plant tissue also will be analyzed for soluble
carbohydrate, starch and chlorophyll.  Sections of roots and leaves
would examine other physiological processes that might be affected as a
result of exposure to microgravity.  All data will be compared with
data gathered from 1g ground controls conducted at a later date using
identical hardware.

     Dr. Mary Musgrave of Louisiana State University is the Principal
Investigator.  The experiment is sponsored by the Life Sciences
Division of NASA's Office of Space Science and Application.  The
experiment is managed by the Kennedy Space Center.

COMMERCIAL GENERIC BIOPROCESSING APPARATUS (CGBA)

     The Commercial Generic Bioprocessing Apparatus (CGBA) payload
is sponsored by NASA's Office of Advanced Concepts and Technology and
is developed by BioServe Space Technologies, a NASA Center for the
Commercial Development of Space (CCDS) at the University of Colorado,
Boulder.  The purpose of the CGBA is to allow a wide variety of
sophisticated biomaterials, life sciences and biotechnology
investigations to be performed in one apparatus in the microgravity
environment.

Commercial Investigations

     During the STS-54 mission, the CGBA will support 28 separate
commercial investigations, loosely classified in three application
areas:  biomedical testing and drug development, controlled ecological
life support system (CELSS) and agricultural development and
manufacture of biological- based materials.

     Biomedical Testing and Drug Development:  To collect information
on how microgravity affects biological organisms, the CGBA will include
12 biomedical test models.  Of the 12 test models, five are related to
immune disorders.

     One will investigate the process in which certain cells engulf and
destroy foreign materials (phagocytosis); another will study bone
marrow cell cultures; two others will study the ability of the immune
system to respond to infectious-type materials (lymphocyte and T-cell
induction) and one will investigate the ability of immune cells to kill
infectious cells (TNF- Mediated Cytotoxicity).

     The other seven test models -- which are related to bone and
developmental disorders, wound healing, cancer and cellular disorders
-- will investigate bone tissue formation, brine shrimp development,
pancreas and lung development, tissue regeneration, inhibition of cell
division processes, stimulation of cell division processes and the
ability of protein channels to pass materials through cell membranes.

     Test model results will provide information to better understand
diseases and disorders that affect human health, including cancer,
osteoporosis and AIDS.  In the future, these models may be used for the
development and testing of new drugs to treat these diseases.

     CELSS Development:  To gain knowledge on how microgravity affects
micro-organisms, small animal systems, algae and higher plant life.
The CGBA will include 10 ecological test systems.  Four test systems
will examine miniture wasp and fruit fly development, seed germination
and seedling processes for CELSS studies.

     Another four test systems will investigate bacterial products and
processes and bacterial colonies for waste management applications.
Two other systems (Triiodid and Zirconium Peroxide) will study new
materials to control build-up of unwanted bacteria and other
micro-organisms.

      Test system results will provide research information with many
commercial applications.  For example, evaluating higher plant growth
in microgravity could lead to new commercial opportunities in
controlled agriculture applications.  Test systems that alter
micro-organisms or animal cells to produce important pharmaceuticals
later could be returned to Earth for large-scale production.
Similarly, it may be possible to manipulate agricultural materials to
produce valuable seed stocks.

     Biomaterials Products and Processes:  The CGBA also will be used
to investigate six different biomaterials products and processes.  Two
investigations will attempt to grow large protein and RNA crystals to
yield information for use in commercial drug development.  A third
investigation will evaluate the assembly of virus shells for use in a
commercially- developed drug delivery system.

     Another investigation will attempt to form a homogenous matrix of
special light-sensitive biological molecules called bacteriorhodopsin.
Such a matrix may be used in novel electronic mass storage systems
associated with computers.  A fifth experiment will use bacteria to
form magnetosomes (tiny magnets) for potential use in advanced
electronics.  A sixth investigation will use fibrin clot materials as a
model of potentially implantable materials that could be developed
commercially as replacements for skin, tendons, blood vessels and even
cornea.

     Results from the 28 investigations will be considered in
determining subsequent steps toward commercialization.  STS-54 marks
the second of six CGBA flights.  Future flights will continue to focus
on selecting and developing investigations that show the greatest
commercial potential.

ART -- Experiment Listing

ART -- Experiment Listing (Continued)


Flight Hardware

     The CGBA consists of 192 Fluids Processing Apparatuses (FPAs)
and 24 Group Activation Packs (GAPs).  Each GAP will house eight FPAs.
The FPAs will contain biological sample materials which are mixed
on-orbit to begin and end an experiment.  Individual experiments will
use two to 12 FPAs each.

     Half of the FPAs and GAPs will be stored in the orbiter middeck in
two Commercial Refrigerator Incubator Modules (CRIM).  The other half
will be stored in a standard stowage locker.  Each CRIM holds six GAPs
and will be operated at 37 degrees Celsius (98.6 degrees F. --
mammalian body temperature) to support cell culture investigations.

     FPA:  Sample materials are contained inside a glass barrel that has
rubber stoppers to separate three chambers.  For each investigation,
the chambers will contain precursor, initiation and termination fluids,
respectively.  The loaded glass barrel will be assembled into a plastic
sheath that protects the glass from breakage and serves as a second
level of sample fluid containment.

     The FPAs are operated by a plunger mechanism that will be
depressed on-orbit, causing the chambers of precursor fluid and the
stoppers to move forward inside the glass barrel.  When a specific
stopper reaches an indentation in the glass barrel, initiation fluid
from the second chamber is injected into the first chamber, activating
the biological process.

     Once processing is complete, the plunger will again be depressed
until the termination fluid in the third chamber is injected across the
bypass in the glass barrel into the first chamber.

     GAP:  The GAP consists of a 4-inch diameter plastic cylinder and
two aluminum endcaps.  Eight FPAs will be contained around the inside
circumference of the GAP cylinder.  A crank extends into one end of the
GAP and attaches to a metal pressure plate.  By rotating the crank, the
plate will advance and depress the eight FPA plungers simultaneously.

On-orbit Operations

     Mission Specialists Susan Helms and Greg Harbaugh are the primary
and backup crew members, respectively, responsible for CGBA
operations.  Upon reaching orbit, they will initiate the various
investigations by attaching a crank handle to each GAP.

     Turning the crank will cause an internal plate to advance and push
the plungers on the contained FPAs.  This action causes the fluids in
the forward chambers of each FPA to mix.  Most of the GAPs will be
activated on either the first or second flight day.

ART - CGBA Group Activiation Pack

ART - CGBA Fluid Processing Apparatus

     The crew will terminate the investigations in a manner similar to
activation.  Attaching and turning the GAP crank will cause further
depression of the FPA plungers causing the fluid in the rear chamber to
mix with the processed biological materials.  This fluid typically will
stop the process or "fix" the sample for return to Earth in a preserved
state.  Each of the 24 GAPs will be terminated at different time points
during the mission.  In this manner, sample materials can be processed
from as little as 2 hours to nearly the entire mission duration.

     For most of the investigations, simultaneous ground controls will
be run.  Using identical hardware and sample fluids and materials,
ground personnel will activate and terminate FPAs in parallel with the
flight crew.  Synchronization will be accomplished based on indications
from the crew as to when specific GAPs are operated.  A temperature
controlled environment at NASA's Kennedy Space Center will be used to
duplicate flight conditions.

     After Endeavor has landed, the CRIMs and stowage locker will be
turned over to Bioserve personnel for deintegration.  Some sample
processing will be performed at Kennedy.  Most FPAs will be shipped or
hand- carried back to the sponsoring labs for detailed analysis.

     Dr. Marvin Luttges, Director of the Bioserve CCDS, is Program
Manager for CGBA.  Drs. Louis Stodieck and Michael Robinson, also of
Bioserve, are responsible for mission management.

PHYSIOLOGICAL AND ANATOMICAL RODENT EXPERIMENT .02

Principal Investigator Kenneth M. Baldwin, Ph.D.
Department of Physiology and Biophysics
University of California, Irvine

Co-Investigator Vincent J. Caiozzo, Ph.D.
Department of Orthopaedic Surgery, College of Medicine
University of California, Irvine

     The second Physiological and Anatomical Rodent Experiment
(PARE.02) is a secondary payload flight experiment located in a Space
Shuttle's mid- deck locker.

     The goal of PARE.02 is to determine the extent to which short-
term exposure to microgravity alters the size, strength and endurance
capacity (stamina) of skeletal muscles normally used to help support
the body against the force of gravity.

     The study, managed by NASA's Ames Research Center, Mountain View,
Calif., will use rodents because their muscles are known to respond
rapidly to altered gravity forces.

     When individuals are exposed to the microgravity of space, there
appears to be a significant loss in muscle mass.  This appears to be
because the muscle must no longer exert a sufficient level of force,
which produces a signal to the body to conserve mass.  However, the
loss of muscle mass hinders one's capability to function when returning
to Earth.  All movement patterns are difficult, and the individual may
be prone to accidents because of this instability.  Scientists need to
find the extent to which the muscle atrophies, what impact the atrophy
process has on muscle performance and how to prevent the atrophy from
occurring.

     Second, the problem of muscle atrophy is similar in part to what
is seen on Earth during the normal aging.  As one gets older, he/she
becomes less physically active and the degree of muscle disuse is
exaggerated.  This leads to the same problems as occur during exposure
to microgravity.  Thus, if the problem of atrophy in space can be
solved, scientists should have a good insight for maintaining the
muscle system in a more viable condition as humans age.

     Millions of dollars are spent annually to treat older individuals
with injuries and disabilities resulting from the general problem of
muscle and bone weakness, particularly in the female population.

     The information derived from such a project has obvious practical
relevance to the entire health care industry.  Any insight that can be
generated to prevent body dysfunction and injury, as well as to
rehabilitate the musculoskeletal system from the effects of disuse
atrophy, are very important to the broad range population base of our
society.

     With the advent of the Space Shuttle program and Spacelab, it is
now possible to expose both humans and animals to the unique
environment of microgravity.  In this way scientists can begin to
partition out the specific effects of gravity in regulating the
structural and functional properties of the organ systems of the body.

     The Shuttle makes it possible for life to exist in a new
environment that is entirely foreign to the body, thereby enabling
scientists to understand how the force of gravity normally impacts
health and well-being.

     This is the second phase of this research experiment.  The first
studied the effects of microgravity on how the muscle cells process the
food humans eat and transform the food into the energy necessary to
enable the muscles to function.  The experiment distinguished that the
muscles isolated from animals exposed to zero gravity had a reduced
capacity to process fat substrate while retaining a normal capacity to
process carbohydrate for energy.

     This finding has important implications if it occurs in the intact
individual, because it would force a person to use his/her energy
stores of carbohydrate at a faster rate.  When this occurs the muscle
loses its stamina and the individual cannot sustain physical activity
for as long a time.

     The PARE.02 project will examine the extent to which the muscle
loses its stamina after exposure to microgravity for 6 days.

     NASA's Ames Research Center provides payload and science
management and support for PARE.02.  The project is sponsored by the
Life Sciences Division of NASA's Office of Space Science and
Applications.

SOLID SURFACE COMBUSTION EXPERIMENT (SSCE)

Principal Investigator Professor Robert A. Altenkirch
Dean of Engineering, Mississippi State University

     The purpose of the SSCE is to study the physical and chemical
mechanisms of flame propagation over solid fuels in the absence of
gravity-driven buoyant or externally-imposed airflows.  The
controlling mechanisms of flame propagation in microgravity are
different than in normal gravity.

     On Earth, gravity causes the air heated by the flame to rise.
     This air flow, called buoyant convention, feeds oxygen to the
flame and cools the fire, creating competing effects.  In microgravity,
this flow is absent.  Therefore, the fire is sustained only by the
oxygen that it consumes as it migrates along the fuel's surface.  The
results of the SSCE have a practical application in the evaluation of
spacecraft fire hazards, as well as providing a better understanding of
flame propagation in microgravity and on Earth.

     The SSCE occupies four standard lockers in the orbiter middeck.
The experiment consists of two parts -- the chamber module and the
camera module.  The chamber module consists of a sealed combustion
chamber which houses the sample and is filled with a combination of
oxygen and nitrogen.  The chamber has two perpendicular viewports --
one on the side and one on the top.

     Two 16-mm color movie cameras mounted on the camera module record
the combustion process through the viewports.  In addition,
thermocouples measure temperature data while a pressure transducer
measures changes in chamber pressure.  These data are stored in the
experiment computer for post-flight analysis.

     Ashless filter paper was tested on the first five flights with
different mixtures of oxygen and nitrogen and with varying pressures.
The final three tests will use polymethylmethacrylate (PMMA), commonly
known as Plexiglas*.  Typically, one configuration will be tested per
mission.  For this mission, the chamber will contain a 35:65 ratio by
volume of oxygen to nitrogen at a total pressure of 1.0 atmosphere.

     A crew member provides power to the experiment and by activating a
switch, the crew member ignites the fuel and data collection begins.
After approximately 75 seconds, the sample self-extinguishes and data
collection ceases.  The entire process takes approximately 25 minutes.

     This is the sixth in a series of eight experiments studying flame
propagation in space.  The experiment was flown aboard the STS-41, STS-
40, STS-43, STS-50 and STS-47 Shuttle missions in October 1990, June
1991, August 1991, June 1992 and September 1992, respectively.


ART - SSCE

     SSCE was conceived by Professor Robert A. Altenkirch, Dean of
Engineering at Mississippi State University, and was built by the NASA
Lewis Research Center, Cleveland.  The project is sponsored by the NASA
Microgravity Science and Applications Division of the Office of Space
Science and Applications.

APPLICATION SPECIFIC PREPROGRAMMED EXPERIMENT CULTURE
SYSTEM PHYSICS OF TOYS (ASPEC)

Physics of Toys

    The STS-54 mission will carry a collection of children's toys
for an educational post-flight videotape on the Physics of Toys.  A
similar opportunity took place on STS-51D in April 1985, and the
subsequent videotape of demonstrations conducted by the crew has become
one of the most popular educational resources NASA has offered to
schools.

    Toys have long been used to help teach basic and advanced
scientific principles and concepts of force, motion and energy.  Many
toys depend on these principles and concepts to function.  Although
teachers are able to anticipate what toys may do in space, free from
the gravity vector, unexpected actions may be observed.  The
possibility of discovery turns Physics of Toys from just a collection
of valuable science demonstrations into legitimate science
experiments.

    The tape to be created on STS-54 will feature new toys, toys
that have been flown before and toys that children can make
themselves.  The tape will be available to schools in the Fall of
1993.  The tape will use toys to teach some basic principles of science
and math to students using an investigative approach.  Children will be
encouraged to investigate the same toys in the normal 1-gravity
environment of Earth and then speculate on what those same toys will do
in the microgravity of space flight.

    In addition to the videotape, selected students in grades 3-5
from the crewmembers' hometowns will actively participate as
investigators and will talk with the orbiting crew.  Through telephone
and television links, these students, while in their classrooms or
other school facilities, will ask the crew questions about the Physics
of Toys experiments.  In preparation for this opportunity, NASA
traveled to each of the schools involved and conducted pre-experiments
with the toys.

    The Physics of Toys experiment is scheduled around noon EST on
flight day 3.  The experiment will begin with a brief videotape showing
highlights of the mission and a few of the coming events.  There will
be a brief introduction to the experiment and then the first crewmember
will take questions.  Only one school will be able to talk to a
crewmember at a time.  Each school will have approximately 8 minutes.
The order of the crewmembers and schools is as follows.



    o  Sacred Heart School, Bronx, N.Y., will experiment with car
and track and klacker balls.  (Mario Runco)
    o  Thomas A. Edison Elementary School, Willoughby, Ohio, will
experiment with a basketball and magnetic marbles.  (Greg Harbaugh)
    o  Shaver Elementary School, Portland, Ore., will experiment
with swimming toys and a flipping mouse.  (Susan Helms)
    o  Westwood Heights Schools, Flint, Mich., will experiment with
gravitrons and a balloon helicopter.  (Donald McMonagle)

        Any time remaining in the experiment after all schools have
asked their questions will be filled with selected demonstration of
flying toys by crew Commander John Casper.

STS-54 CREW BIOGRAPHIES

     John H. Casper, 48, Col., USAF, is Commander of Endeavour's third
space mission.  Selected to be an astronaut in 1984, Casper, from
Gainesville, Ga., is making his second Shuttle flight.

     Casper served as Pilot on Atlantis' STS-36 mission in February
1990, which carried Department of Defense payloads and a number of
secondary payloads.

     A graduate of Chamblee High School in Chamblee, Ga., in 1961,
Casper received a bachelor of science degree in engineering science
from the U.S.  Air Force Academy in 1966 and a master of science degree
in astronautics from Purdue University in 1967.  He is a 1986 graduate
of the Air Force Air War College.

     Casper received his pilot wings at Reese Air Force Base, Texas, in
1968 and has logged more than 6,000 flying hours in 50 different
aircraft.  His first Shuttle mission lasted 106 hours.

     Donald (Don) R. McMonagle, 38,  Col., USAF, is Pilot of STS-54.
Born in Flint, Mich., McMonagle was selected as a pilot astronaut in
1987 and made his first flight as a mission specialist aboard Discovery
on STS-39 in April 1991, an unclassified Department of Defense
mission.

     McMonagle graduated from Hamady High School in Flint in 1970.  He
holds a bachelor of science degree in astronautical engineering from
the U.S. Air Force Academy and a master of science in mechanical
engineering from California State University, Fresno.

     He graduated from pilot training at Columbus Air Force Base,
Miss., in 1975 and has more than 4,200 hours of flying experience in a
variety of aircraft, primarily the T-38, F-4, F-15 and F-16.  He logged
more than 199 hours in space on his first Shuttle mission.

     Gregory (Greg) J. Harbaugh, 35, will serve as Mission Specialist
1.  Before being selected as an astronaut in 1978, Harbaugh held
engineering and technical management positions in various areas of
Space Shuttle flight operations -- particularly data processing systems
-- and supported real-time Shuttle operations from the JSC Mission
Control Center for most of the flights from STS-1 to STS-51L.

     Harbaugh, who considers Willoughby, Ohio, as his hometown,
graduated from Willoughby South High School in 1974, received a
bachelor of science degree in aeronautical and astronautical
engineering from Purdue University in 1978 and a master of science
degree in physical science from the University of Houston-Clear Lake in
1986.

     Harbaugh flew as a mission specialist on STS-39 and was
responsible for operation of the remote manipulator system robot arm
and the Infrared Background Signature Survey spacecraft.  With the
completion of the mission, he had logged 199 hours in space.

     Mario Runco Jr., 39,  Lt. Cdr., USN, will serve as Mission
Specialist 2.  From Yonkers, N.Y., Runco graduated from Cardinal Hayes
High School in the Bronx, N.Y., in 1970.

     He received a bachelor of science degree in meteorology and
physical oceanography from City College of New York in 1974 and a
master of science degree in meteorology from Rutgers University, New
Brunswick, N.J., in 1976.

     After graduating from Rutgers, Runco worked for a year as a
research hydrologist conducting ground water surveys for the U.S.
Geological Survey on Long Island, N.Y.  He worked as a New Jersey State
Trooper until entering the U.S. Navy in 1978 and being commissioned
that same year.

     He served in various Navy posts, being designated a Naval Surface
Warfare Officer and conducting hydrographic and oceanography surveys of
the Java Sea and Indian Ocean before joining NASA.

     Runco served as a mission specialist aboard Atlantis on STS-44 in
November 1991, which deployed the Defense Support Program satellite and
conducted two Military Man in Space experiments, three radiation
monitoring experiments and numerous medical tests.  Runco logged more
than 166 hours on that flight.

     Susan J. Helms, 33, Capt., USAF, will serve as Mission Specialist 3
on STS-54.  From Portland, Ore., she was selected as an astronaut in
1990.

     Helms graduated from Parkrose Senior High School in Portland in
1976, received a bachelor of science degree in aeronautical engineering
from the U.S. Air Force Academy in 1980 and a master of science degree
in aeronautics and astronautics from Stanford University in 1985.

     Helms was an F-16 weapons separation engineer at Eglin Air Force
Base, Fla., and served as an assistant professor of aeronautics at the
academy.  In 1987, she attended Air Force Test Pilot School at Edwards
Air Force Base, Calif. and worked as a flight test engineer and project
officer on the CF-18 aircraft at CFB Cold Lake, Alberta, Canada.  As a
flight test engineer, she has flown in 30 different types of U.S. and
Canadian military  aircraft.  This will be her first Space Shuttle
flight.

MISSION MANAGEMENT FOR STS-54

NASA HEADQUARTERS, WASHINGTON, D.C.

Office of Space Flight

Jeremiah W. Pearson III - Associate Administrator
Brian O'Connor - Deputy Associate Administrator
Tom Utsman - Director, Space Shuttle
Leonard Nicholson - Manager, Space Shuttle
Brewster Shaw - Deputy Manager, Space Shuttle

Office of Space Science and Applications

Dr. Lennard Fisk - Associate Administrator
Al Diaz - Deputy Associate Administrator
Dr. George Newton - Acting Director, Astrophysics Division
Robert Benson - Director, Flight Systems Division
David Jarrett - DXS Program Manager
Dr. Louis Kaluzienski - DXS Program Scientist

Office of Advanced Concepts and Technology

Gregory M. Reck - Acting Associate Administrator
Ray J. Arnold, Director - Commercial Innovation & Competitiveness
Richard H. Ott, Director - Commercial Flight Experiments
Garland C. Misener - Chief, Flight Requirements & Accommodations

Office of Space Communications

Charles Force - Associate Administrator
Jerry Fitts - Deputy Associate Administrator
Eugene Ferrick - Director, Space Network
Jimie Maley - Manager, Launch and Space Segment
Daniel Brandel - Manager, TDRSS Continuation
Raymond Newman - Manager, Ground Segment
Wilson Lundy - Manager, White Sands Space Network Complex

Office of Safety and Mission Quality

Col. Frederick Gregory - Associate Administrator
Charles Mertz - (Acting) Deputy Associate Administrator
Richard Perry - Director, Programs Assurance

KENNEDY SPACE CENTER, FLA.

Robert L. Crippen - Director
James A. "Gene" Thomas - Deputy Director
Jay F. Honeycutt - Director, Shuttle Management and Operations
Robert B. Sieck - Launch Director
John J. "Tip" Talone - Endeavour Flow Director
J. Robert Lang - Director, Vehicle Engineering
Al J. Parrish - Director of Safety Reliability and Quality Assurance
John T. Conway - Director, Payload Management and Operations
P. Thomas Breakfield - Director, Shuttle Payload Operations
Joanne H. Morgan - Director, Payload Project Management
Roelof Schuiling - STS-54 Payload Processing Manager

MARSHALL SPACE FLIGHT CENTER, HUNTSVILLE, ALA.

Thomas J. Lee - Director
Dr. J. Wayne Littles - Deputy Director
Harry G. Craft - Manager, Payload Projects Office
Alexander A. McCool - Manager, Shuttle Projects Office
Dr. George McDonough - Director, Science and Engineering
James H. Ehl - Director, Safety and Mission Assurance
Otto Goetz - Manager, Space Shuttle Main Engine Project
Victor Keith Henson - Manager, Redesigned Solid Rocket Motor
Project
Cary H. Rutland - Manager, Solid Rocket Booster Project
Parker Counts - Manager, External Tank Project

JOHNSON SPACE CENTER, HOUSTON

Aaron Cohen - Director
Paul J. Weitz - Deputy Director
Daniel Germany - Manager, Orbiter and GFE Projects
David Leestma - Director, Flight Crew Operations
Eugene F. Kranz - Director, Mission Operations
Henry O. Pohl - Director, Engineering
Charles S. Harlan - Director, Safety, Reliability and Quality
Assurance

STENNIS SPACE CENTER, BAY ST LOUIS, MISS.

Roy S. Estess - Director
Gerald Smith - Deputy Director
J. Harry Guin - Director, Propulsion Test Operations

AMES-DRYDEN FLIGHT RESEARCH FACILITY, EDWARDS, CALIF.

Kenneth J. Szalai - Director
T. G. Ayers - Deputy Director
James R. Phelps - Chief, Shuttle Support Office


AMES RESEARCH CENTER, MOUNTAIN VIEW, CALIF.

Dr. Dale L. Compton - Director
Victor L. Peterson - Deputy Director
Dr. Joseph C. Sharp - Director, Space Research

GODDARD SPACE FLIGHT CENTER, GREENBELT, MD.

Dr. John Klineberg - Center Director
Thomas E. Huber - Director, Engineering Directorate
Theodore C. Goldsmith - Project Manager, Shuttle Small Payloads
Steven C. Dunker - DXS Project Manager
Vernon J. Weyers -  Director, Flight Projects
Dale L. Fahnestock - Director, Mission Operations and Data Systems
Daniel A. Spintman - Chief, Networks Division
Vaughn E. Turner - Chief, Communications Division
Charles Vanek - Project Manager, TDRS
Thomas E. Williams - Deputy Project Manager, TDRS
Anthony B. Comberiate - TDRS Manager
Gary A. Morse - Network Director


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