STS-51 PRESS KIT




NATIONAL AERONAUTICS AND SPACE ADMINISTRATION





SPACE

SHUTTLE

MISSION

STS-51

PRESS KIT

JULY 1993








ACTS/ORFEUS-SPAS

Advanced Communications Technology Satellite
Orbiting and Retrievable Far and Extreme Ultraviolet Spectrometer- 
Shuttle Pallet Satellite








PUBLIC AFFAIRS CONTACTS

For Information on the Space Shuttle

Ed Campion                  Policy/Management   
  Headquarters, Wash., D.C.

James Hartsfield             Mission Operations/EVA
  Johnson Space Center, 	Astronauts
  Houston

Bruce Buckingham             Launch Processing
  Kennedy Space Center, Fla.	KSC Landing Information

June Malone                   External Tank/SRBs/SSMEs
  Marshall Space Flight
  Center, Huntsville, Ala.

Nancy Lovato                  DFRF Landing Information
  Dryden Flight Research 
  Facility, Edwards, Calif.


For Information on NASA-Sponsored STS-51 Experiments

Michael Braukus                  ORFEUS-SPAS 
  Headquarters, Wash., D.C.      ACTS hardware

Charles Redmond                  ACTS experiments
  Headquarters, Wash., D.C.


CONTENTS

GENERAL BACKGROUND
General Release	1
Media Services Information	3
Quick-Look Facts	4
Payload and Vehicle Weights	5
STS-51 Summary Timeline	6
Space Shuttle Abort Modes	7
Crew Responsibilities	8

CARGO BAY PAYLOADS & ACTIVITIES
Advanced Communication Technology Satellite/Transfer Orbit 
Stage (ACTS) Hardware	10
	ACTS Overall Description	12
	Transfer Orbit Stage Hardware & Operations	17
	ACTS Experiments	21
Orbiting Retrievable Far and Extreme Ultraviolet Spectrometer -
Shuttle Pallet Satellite (ORFEUS-SPAS)	42
STS-51 ORPHEUS/SPAS Rendezvous Operations	50
Limited Duration Space Environment Candidate Materials Exposure 
(LDCE)	51

CABIN PAYLOADS
Chromosome and Plant Cell Division in Space (CHROMEX-4)	51
STS-51 EVA Activities	53
Radiation Monitoring Equipment-III (RME-III)	54
Air Force Maui Optical Site (AMOS)	54
Auroral Photography Experiment-B (APE-B)	54
Commercial Protein Crystal Growth (CPCG)	54
High Resolution Shuttle Glow Spectroscopy-A (HRSGS-A)	55
IMAX	55
Investigations into Polymer Membrane Processing (IPMP)	55

CREW BIOGRAPHIES & MISSION MANAGEMENT
STS-51 Crew Biographies	56
STS-51 Mission Management	58







RELEASE:  93-121

ACTS DEPLOYMENT HIGHLIGHTS STS-51 MISSION

     The deployment of a satellite which will serve as a testbed for 
technology leading to a new generation of communication satellites 
and the deployment and retrieval of a U.S./German free-flying 
scientific observation satellite highlight NASA's Shuttle Mission 
STS-51.

     The mission, which is scheduled for mid-July, 1993, also will 
see Space Shuttle Discovery and her five-person crew conduct a 
variety of experiments on the effects of microgravity on various 
plants and materials along with other payloads which will perform 
photographic observations during the mission.

     The Advanced Communications Technology Satellite (ACTS) program 
provides for the development and flight test of high-risk, advanced 
communications satellite technology.  Using sophisticated antenna 
beams and advanced on-board switching and processing systems, ACTS 
will pioneer new initiatives in communications satellite technology.

     The Orbiting and Retrievable Far and Extreme Ultraviolet 
Spectrometer - Shuttle Pallet Satellite (ORFEUS-SPAS) mission is the 
first of a series of missions using the German built ASTRO-SPAS 
science satellite.  ASTRO-SPAS is a spacecraft designed for launch, 
deployment and retrieval by the Space Shuttle.

     Once deployed from the Shuttle by its Remote Manipulation 
System (RMS), ASTRO-SPAS operates quasi-autonomously for several 
days in the Shuttle vicinity.  After completion of the free flight 
phase, the satellite is retrieved by the RMS and returned to Earth.  
ORFEUS-SPAS is an astrophysics mission, designed to investigate very 
hot and very cold matter in the universe. 

     On the fifth day of the mission, two STS-51 crew members will 
perform a 6-hour extravehicular activity (EVA), or spacewalk, as 
part of a continuing series of test spacewalks NASA is conducting to 
increase experience with spacewalks and refine spacewalk training 
methods.

     In addition to performing tasks that investigate a 
spacewalker's mobility in general, the astronauts will evaluate 
several tools that may be used during the servicing of the Hubble 
Space Telescope (HST) later this year on mission STS-61, including a 
power socket wrench, a torque wrench, foot restraint, safety tethers 
and tool holder. 

     Leading the  STS-51 crew will be Mission Commander Frank 
Culbertson who will be making his second space flight.  The pilot 
for the mission is William Readdy, making his second flight.  The 
three mission specialists for this flight are Daniel Bursch (MS-1), 
James Newman (MS-2) and Carl Walz (MS-3), all three of whom will be 
making their first flight.

     The mission duration for STS-51 is planned for 9 days with a 
scheduled landing at the Kennedy Space Center, Fla.

     This will be the 17th flight of Space Shuttle Discovery and the 
57th flight of the Space Shuttle system.


(end general release - background information follows)




   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 
for 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, 
representatives from the science team, will occur at least once per 
day.  The updated NASA Select television schedule will indicate when 
mission briefings are planned.



   STS-51 QUICK-LOOK

Launch Date/Site:	        July 1993, Kennedy Space Center - Pad 39B

Launch Time:			TBD

Orbiter:			Discovery (OV-103) - 17th Flight

Orbit/Inclination:		160 nautical miles/28.45 degrees

Mission Duration:		8 days, 21 hours, 59 minutes 

Landing Time/Date:		TBD

Primary Landing Site:		Kennedy Space Center, Fla.

Abort Landing Sites:	   Return to Launch Site - KSC, Fla.
			   Transatlantic Abort landing:	   Banjul, The Gambia;
			   Ben Guerir, Morocco; Moron, Spain
			   Abort Once Around: Edwards AFB, Calif.

Crew: 			   Frank Culbertson, Commander (CDR)
			   William Readdy, Pilot (PLT)
			   Jim Newman, Mission Specialist 1 (MS1)
			   Dan Bursch, Mission Specialist 2 (MS2)
			   Carl Walz, Mission Specialist 3 (MS3)


Cargo Bay Payloads & Activities
     Advanced Communication Technology Satellite/Transfer Orbit
      Stage (ACTS/TOS)
     Orbiting Retrievable Far and Extreme Ultraviolet Spectrometer-
       Shuttle 
     Pallet Satellite (ORFEUS-SPAS)
     Limited Duration Space Environment Candidate Materials
      Exposure (LDCE)

In-Cabin Payloads
     Air Force Maui Optical Site (AMOS)
     Auroral Photography Experiment-B (APE-B)
     Commercial Protein Crystal Growth (CPCG)
     Chromosome and Plant Cell Division in Space (CHROMEX)
     High Resolution Shuttle Glow Spectroscopy-A (HRSGS-A)
     IMAX
     Investigations into Polymer Membrane Processing (IPMP)
     Radiation Monitoring Equipment-III (RME-III)




   STS- 51 PAYLOAD AND VEHICLE WEIGHTS

Vehicle/Payload	Pounds
Orbiter (Discovery) empty and 3 SSMEs	 173,117
Advanced Communications Satellite/Transfer Orbit Stage	  26,756
ACTS Support Equipment	   6,394
ORFEUS/SPAS	 7,070
LDCE/GAS can	 770
APE	   41
CHROMEX	  69
CPCG	 70
HRSGS	 91
IMAX Camera System	   320
IPMP	  20
RME	  7
DSOs/DTOs	162
Total Vehicle at SRB Ignition	  4,525,219
Orbiter Landing Weight	   203,639




   STS-51 SUMMARY TIMELINE


Flight Day One	
Ascent	
OMS-2 (160 n.m. x 161 n.m.)	
Remote Manipulator System checkout	
CHROMEX check	
CPCG activation	
RME activation	
ACTS/TOS deploy	
RCS, OMS Separation burns 	
(161 n.m. x 173 n.m.)

Flight Day Two	
OMS, RCS burns (158 n.m. x 159 n.m.)	
ORFEUS/SPAS checkout	
ORFEUS/SPAS release	
RCS Separation burns (158 n.m. x 159 n.m.)	
CHROMEX check	
Cabin depress to 10.2 psi	

Flight Day Three	
Stationkeeping burns (158 n.m. x 159 n.m.)	
IPMP activation	
CHROMEX check	
	
Flight Day Four	
EMU checkout	
Stationkeeping burns (158 n.m. x 159 n.m.)	
RME check	
	
Flight Day Five	
Extravehicular activity preparations	
Extravehicular activity (six hours)	
Stationkeeping burns (158 n.m. x 159 n.m.)	
CHROMEX check	

Flight Day Six
Stationkeeping burns (158 n.m. x 159 n.m.)
APE setup
HRSGS setup
CHROMEX check
LDCE operations

Flight Day Seven
Stationkeeping burns
(158 n.m. x 159 n.m.)
LDCE operations
APE operations
HRSGS operations
HRSGS stow
CHROMEX check
RME check

Flight Day Eight
ORFEUS/SPAS rendezvous
ORFEUS/SPAS berth
CHROMEX check
DTO 412: Fuel Cell shutdown

Flight Day Nine
Cabin repress to 14.7 psi
Flight Control Systems checkout
Reaction Control System hot-fire
AMOS
CHROMEX check
Cabin stow
DTO 412: Fuel Cell restart

Flight Day Ten
Deorbit preparations
Deorbit burn
Entry
Landing






SPACE SHUTTLE ABORT MODES

     Space Shuttle launch abort philosophy aims toward 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 Edwards 
Air Force Base, Calif.

     * Transatlantic 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, and 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-51 contingency landing sites are the Kennedy Space Center, 
Edwards Air Force Base, Banjul, Ben Guerir and Moron.




   STS-51 CREW RESPONSIBILITIES

TASK/PAYLOAD          PRIMARY          BACKUP

ACTS/TOS               Walz            Bursch
ORFEUS/SPAS           Newman           Newman

Middeck experiments:
APE                    Walz            Newman
CHROMEX               Newman           Readdy
CPCG                  Bursch           Culbertson
IMAX                  Readdy           Walz
IPMP                  Newman           Bursch
HRSGS                 Newman           Walz
AMOS                  Readdy           Bursch
RME                   Walz  

DTO's/DSO's:
EVA                   Walz (EV1)       Newman (EV2), Readdy (IV)
ET Photo              Walz             Newman
Fuel Cell             Readdy           Culbertson
PGSC                  Newman           Walz
Thermal Print (TIPS)  Newman           Walz
ALBRT                 Culbertson       Bursch
Laser Range (hand)    Readdy           Bursch
Laser Range (cargo bay)  Bursch        Readdy
GPS                   Walz             Newman
PCMMU                 Newman           Walz
VRCS                  Readdy           Newman
Exercise              Culbertson       All
Entry ortho tolerance Newman           Walz
Visual vestibular     Newman          
Posture               Readdy           Walz
Skeletal/muscle       Readdy           All
Gastro function       Bursch           Newman
Blood IV              Readdy           Bursch
ENH stand             Culbertson       Newman, Walz

Other Responsibilities:
Photography/TV        Readdy           Walz, Culbertson
Earth observations    Readdy           Culbertson
In-flight Maintenance Walz             Readdy
Medic                 Readdy           Bursch



ADVANCED COMMUNICATIONS TECHNOLOGY 
SATELLITE (ACTS) HARDWARE

	The Advanced Communications Technology Satellite (ACTS) provides 
for the development and flight test of high-risk, advanced 
communications satellite technology.  Using advanced antenna beams 
and advanced on-board switching and processing systems, ACTS will 
pioneer new initiatives in communications satellite technology.

	ACTS provides new communications satellite technology for:
      * Operating in the Ka-band (30/20 GHz) where there is 2.5 GHz of
        spectrum available (five times that available at lower frequency
        bands)

      * Very high-gain, multiple hopping beam antenna systems which 
        permit smaller aperture Earth stations

      * On-board baseband switching which permits interconnectivity
        between users at an individual circuit level

      * A microwave switch matrix which enables gigabit per second 
        communication between users.

	These technologies provide for up to three times the 
communications capacity for the same weight as today's satellites 
(more cost effective), much higher rate communications between users 
(20 times that offered by conventional satellites), greater 
networking flexibility and on-demand digital services not currently 
available from communications systems today.  The development and 
flight validation of this advanced space communications technology by 
NASA's ACTS will allow industry to adapt this technology to their 
individual commercial requirements at minimal risk.  It also will aid 
the U.S. industry in competing with European and Asian companies 
which have, in the last decade, developed significant capabilities 
for producing communications satellites and associated ground 
equipment.

	ACTS technologies, which are applicable for a variety of frequency 
bands, will potentially lower the cost or technical threshold so that 
such new services as remote medical image diagnostics, global 
personal communications, real-time TV transmissions to airliners, 
direct transmission of reconnaissance image data to battlefield 
commanders and interconnection of supercomputers will be feasible.  
Technology spin-off is already occurring.

	Motorola currently is adapting the ACTS Ka-band and on-board 
switching technologies for their $3 billion Iridium satellite system, 
which will provide global voice/data communications services.  Norris 
Communications also is proceeding with a Ka spot-beam communications 
satellite.


ACTS Overall Description

     ACTS is comprised of a spacecraft bus with basic housekeeping 
functions and a payload, known as the multibeam communications 
package (MCP). 

     At launch, ACTS weighs 6,108 pounds including the propellants 
and the spacecraft adapter and clamp band which remain with the 
Transfer Orbit Stage (TOS) upon separation.  When in the stowed 
configuration in the Shuttle payload bay, ACTS' overall height is 
15.9 feet (5 m) from the spacecraft separation plane to the tip of 
the highest antenna.

     During the transfer orbit phase, the spacecraft is spin 
stabilized, and the antenna reflectors and solar array panels are 
retracted and stowed to provide better load support for these 
appendages.  During the on-orbit mission phase, the spacecraft is 
three-axis stabilized with the large antenna reflectors facing the 
Earth and the solar array panels rotating once per day to track the 
Sun.  On-orbit, ACTS measures 47.1 feet (14 m) from tip to tip of the 
solar arrays and 29.9 feet (9 m) across the main receiving and 
transmitting antenna reflectors.

Spacecraft Bus 

     The spacecraft bus structure is a rectangular box with a 
cylindrical center structure that houses the apogee kick motor (AKM).  
The multibeam antenna subsystem is mounted to the Earth facing panel 
of the spacecraft bus.  The North and South sides are each divided 
into three panels.  These panels are used to mount most of the 
spacecraft bus and MCP electronics equipment.  The spacecraft bus 
provides support functions for the MCP such as electrical and 
mechanical mounting surfaces, attitude control, electrical power, 
thermal control, command reception, telemetry transmission and 
ranging and propulsion for station keeping maneuvers.

Multibeam Communications Package

     The multibeam communications package performs receiving, 
switching, momentary storage, selectable coding and decoding, 
amplifying and transmitting functions for Ka-band time division 
multiple access (TDMA) communications signals.  The multibeam antenna 
(MBA) has fixed beams and hopping spot beams that can be used to 
service traffic needs on a dynamic basis.  (A hopping spot beam is an 
antenna beam on the spacecraft that points at one location on the 
ground for a fraction of a millisecond.  It sends/receives voice or 
data information and then the beam electronically "hops" to a second 
location, then a third and so on.  At the beginning of the second 
millisecond the beam again points at the first location.)

     In addition, the receiving antenna provides signals to the 
autotrack receiver which generates input error signals to the 
attitude control system for spacecraft pointing operations.  Beam 
forming networks (BFN) utilize hopping beams to provide independent 
coverage of the East and West scan sectors, plus coverage for 
isolated locations outside of either sector.  The MBA also has three 
fixed spot beams.  A steerable beam antenna has been incorporated 
into ACTS to provide antenna coverage of the entire disk of the Earth 
as seen from l00 degrees west longitude and to any aircraft or low 
Earth orbit spacecraft, including the Space Shuttle, within view of 
the ACTS.  

ACTS Deployment Sequence

     ACTS will be deployed from Discovery's cargo bay approximately 8 
hours after launch on orbit six.  The TOS burn which will inject ACTS 
into a geosynchronous transfer orbit.  The spacecraft apogee kick 
motor will inject ACTS into a drift orbit.  Finally, ACTS will be 
placed in a geostationary orbit at 100 degrees west longitude over 
the equator, approximately in line with the center of the United 
States.  A geostationary orbit is one where a satellite takes 24 
hours to complete one revolution, thus appearing to remain motionless 
above a single place on the Earth.

     About 2 hours before deployment from the orbiter, the astronauts 
perform a sequence of events beginning with preliminary TOS checks, 
unlatching the TOS cradle and elevating the ACTS/TOS flight element 
to a 42 degree angle for deployment.  The crew will fire the 
"Super*Zip" separation system, and six springs on the TOS aft cradle 
will push the flight element out of the cargo bay.

     The TOS motor firing is controlled by an on-board timer and 
occurs 45 minutes following deployment from the orbiter or about 8 
hours and 45 minutes after STS-51 launch.  The approximately two-
minute burn will place ACTS in a geotransfer orbit.  The apogee kick 
motor burn to inject ACTS into drift orbit will take place 42 1/2 
hours after deployment, approximately 50 1/2 hours into the mission.  
The 7-day drift will allow ACTS to move toward its final station 
location of 100 degrees west longitude.  Firing of the spacecraft's 
thrusters will bring the perigee and apogee radii increasingly closer 
to the geostationary orbit.

     Upon reaching geostationary orbit, ACTS will transition from a 
spinning to a three-axis stabilized spacecraft configuration and 
deploy its solar arrays and antennas.  

     ACTS experiments will begin 12 weeks after launch following the 
placement of the spacecraft on-station and spacecraft checkout.  ACTS 
is designed to have a minimum life of 2 years but will have enough 
station keeping fuel for a 4-year-plus mission.

ACTS Ground Systems and Support

     The facilities and support to be used for the ACTS mission 
phases include the Guam and Carpentersville, N.J.,  C-band telemetry, 
tracking and command stations and the ACTS ground segment.

Tracking, Telemetry and Command

     The ACTS mission telemetry, tracking and command (TT&C) control 
and monitor functions are distributed between two geographically 
separate locations: Lewis Research Center, Cleveland and the Martin 
Marietta Satellite Operations Center (SOC), East Windsor, N.J.  The 
SOC is used to control the ACTS housekeeping functions during both 
the transfer orbit and the on-station phases.

  During the transfer orbit phases, the SOC controls the ACTS through 
the C-band ground stations.  During the on-station phase, command 
parameters generated at the SOC are routed via landlines to Lewis to 
be uplinked to the ACTS via Ka-band.  Status information is displayed 
at the Lewis ACTS master ground station for both the transfer orbit 
and on-station phases.

ACTS Ground Segment

     The ACTS ground segment is comprised of the ACTS master ground 
station, the satellite operations center and the experimenter 
terminals.

ACTS Master Ground Station

     The ACTS master ground station is located at the NASA Lewis 
Research Center.  It includes:

*	The NASA ground station (NGS), which consists of a Ka-band 
radio frequency terminal, two traffic terminals and a reference 
terminal.  It up-converts signals for the baseband processor 
mode of perations to 30 GHz for transmission to ACTS and 
amplifies and down-converts the 20 GHz baseband processor 
modulated signals received from ACTS.  Modulation and 
demodulation of the baseband communications signals are 
performed in the NASA ground station.  It also transmits and 
receives signals in support of the command, ranging and 
telemetry functions for ACTS.

*	The master control station provides network control for the 
spacecraft baseband processor and backup to the satellite 
operations center for configuring the multibeam communications 
package.  The master control station also enables experiment 
execution and telemetry collection.

*	The microwave switch matrix-link evaluation terminal provides 
the capability for the on-orbit testing of the microwave switch 
matrix and the multibeam antenna.  It also will conduct 
wideband communications experiments.

*	The command, ranging and telemetry equipment interfaces with 
theNASA ground station at intermediate frequency and exchanges 
command, ranging and telemetry information to and from the 
master control station, the G.E. SOC and the microwave switch 
matrix-link evaluation terminal.

     The SOC has primary responsibility for generating flight system 
commands and for analyzing, processing and displaying flight system 
telemetry data.  Orbital maneuver planning and execution also are 
handled by the SOC.  The primary housekeeping function is performed 
at the SOC which is linked via land line to the Ka-band command, 
ranging and telemetry equipment at the ACTS master control station.

     The Ka-band experimenter network consists of a variety of ground 
stations to be operated by industry, universities and government 
organizations.  These ground stations have varying communication 
services ranging from High Data Rate (HDR) at 1 gigabit per second, 
to Very Small Aperture Terminal (VSAT) at 1.5 megabits per second, 
aeronautical and ground mobile voice and data at 500 kilabits per 
second and Ultra Small Aperture Terminal (USAT) data at 4800 bits per 
second.


TRANSFER ORBIT STAGE FOR THE STS-51 MISSION

     The Transfer Orbit Stage (TOS) will boost NASA's Advanced 
Communications Technology Satellite from low-Earth orbit into 
geosynchronous transfer orbit with a maximum altitude of 21,519 
nautical miles (34,624 km).  This will be the second mission of the 
Transfer Orbit Stage and the first time it has flown on a Space 
Shuttle mission.

     The Transfer Orbit Stage was first used in September 1992 as the 
upper stage booster for NASA's Mars Observer mission.  Following 
launch on an expendable rocket, the TOS successfully propelled the 
spacecraft on a trajectory from Earth orbit to the red planet.

     The Space Systems Projects Office at NASA's Marshall Space 
Flight Center, Huntsville, Ala., manages the TOS program for NASA.  
That role involves ensuring TOS compliance with over all mission 
requirements, including those for integration with the launch vehicle 
and satellite and flight safety requirements.

Transfer Orbit Stage Description

     The Transfer Orbit Stage, built by Martin Marietta Astronautics 
Group in Denver,  for Orbital Sciences Corp., Dulles, Va., is a 
single-stage, solid-propellant rocket system.  It is the latest 
addition to NASA's upper stage fleet, which includes a range of 
vehicles to boost satellites or spacecraft in the second step of 
their journey to geostationary orbit or toward interplanetary 
destinations.

     TOS, constructed primarily of high-strength aluminum alloy, 
weighs 20,780 pounds (9,426 kg) including solid propellant fuel.  It 
is almost 11 feet (3.3 m) long and about 7.5 feet (2.3 m) in 
diameter.  The satellite, weighing 6,108 pounds (2,771 kg), is 
mounted on top of the Transfer Orbit Stage.  Portions of both the 
satellite and TOS are covered with gold foil multi-layered insulation 
for thermal protection from the Sun.

     Major elements of the TOS system are a solid rocket main 
propulsion system, a navigation and guidance system, a reaction 
control system which is used to adjust TOS attitude or local pointing 
and an airborne support equipment cradle that holds the satellite and 
upper stage in the Shuttle cargo bay and facilitates deployment from 
the orbiter.

     The ORBUS-21 solid rocket motor main propulsion system, 
manufactured by United Technologies Chemical Systems Division, San 
Jose, Calif., will give the primary thrust for the 110 seconds of 
powered flight.  To provide the 59,000 pounds of thrust (262,445 
newtons) to inject the satellite into its transfer orbit, the motor 
will use 18,013 pounds (8,171 kg) of the solid rocket propellant 
HTPB (hydroxyl terminated polybutadiene).

     Pitch (maneuvering upward or downward) and yaw (turning to the 
left or right) will be controlled during the burn by gimballing the 
nozzle of the solid rocket motor with two thrust vector control 
actuators.  Roll control is provided by the reaction control system 
during motor burn.

     TOS guidance and control avionics are based on a laser inertial 
navigation system manufactured by Honeywell, Inc., Clearwater, Fla.  
It acts as the brains of the vehicle, computing location and 
providing signals to the propulsion system to maintain the proper 
trajectory.  All TOS operations are performed autonomously with no 
ground commanding required.  The guidance system uses laser 
gyroscopes with no moving parts, thus reducing chances for 
malfunctions in space.  A telemetry and encoder unit records 
performance data from all on-board electronics and sends it to 
ground control at KSC. 

     The reaction control system thruster assembly, manufactured by 
UTC/Hamilton Standard Division, Windsor Locks, Conn., correctly 
positions the TOS and its payload, based on information from the 
laser inertial navigation system.  The three-axis control system 
uses 12 small maneuvering rockets, which rely on decomposed 
hydrazine as their propellant, to fine-tune the orientation of the 
vehicle and its payload before solid rocket motor ignition.

     The reaction control system also slowly turns the satellite-TOS 
for thermal control to avoid overheating from the sun.  The reaction 
control system makes final attitude adjustments before TOS 
separation from the satellite.

     The equipment needed to adapt the satellite-TOS to the Space 
Shuttle is called the airborne support equipment.  This equipment is 
manufactured by Martin Marietta.  Prior to deployment, the TOS rests 
in the aft cradle and is clamped firmly in the Shuttle's cargo bay 
by the forward cradle.

ACTS/TOS deployment scenario

     During the STS-51 mission, Discovery crew members will initiate 
a predeployment checkout to ensure that all critical TOS systems are 
healthy and ready to deploy.  The upper forward cradle, similar to a 
clamp, will then be unlatched and rotated open.  The satellite-
booster will be elevated 45 degrees out of the cargo bay.  If any 
problems are detected in the combined payload up to this point, it 
can be lowered, relatched and returned to Earth at the end of the 
mission.  If no anomalies are detected, a pyrotechnic system will 
release the satellite-TOS and springs on the cradle will gently 
nudge it out of the orbiter.  The satellite-TOS will coast for 45 
minutes while the Shuttle maneuvers to a safe distance, 11.7 miles 
(18.8 km) away, to avoid a possible collision or damage from the TOS 
solid rocket exhaust plume.

     Once the Transfer Orbit Stage has positioned the satellite in 
the proper attitude, the TOS solid rocket motor will fire for 110 
seconds, accelerating to the 22,800-mph velocity (36,685 km/hr) 
necessary to boost the satellite into its geosynchronous transfer 
orbit.  Then the Transfer Orbit Stage will make final attitude 
adjustments as the satellite speeds toward apogee, the point 
farthest from the Earth in its orbit.

     Shortly after rocket burnout, the satellite will separate from 
the TOS and the TOS will make a perpendicular turn to avoid being in 
the satellite's path.  Later, thrusters and a solid rocket motor on 
the satellite itself will fire to place the satellite into its final 
geosynchronous orbit.  The actual timing of the satellite burn is 
controlled by commands from the ground.

Extra-Vehicular Activity Tools

     If a mechanical problem with the TOS airborne support equipment 
were to develop prior to or after deployment of the satellite-TOS, 
two astronauts can use one or more specially designed tools to 
correct it.  The tools were designed at Marshall Space Flight Center 
and tested under simulated weightless conditions in the center's 
Neutral Buoyancy Simulator water tank.  The actual use of these 
devices is considered unlikely since the airborne support equipment 
itself is fully redundant, with all systems having built-in back-
ups.




   ADVANCED COMMUNICATIONS TECHNOLOGY
SATELLITE (ACTS) EXPERIMENTS PROGRAM

     The Advanced Communications Technology Satellite Experiments 
Program  gives industry, academic, and government organizations an 
opportunity to investigate new ways of communicating.  In 
conjunction with industry, NASA has developed the ACTS and an 
extensive network of ground stations to test and prove pioneering 
communications concepts and technologies that will advance cheaper, 
on-demand, flexible communications.

     The Experiments Program provides access to these new 
telecommunication tools that will be widely used in the 21st 
century.  ACTS experimenters design, fund, and conduct 
investigations.  NASA contributes spacecraft time, manages 
operations, and assists investigators in developing a final 
experiment plan. This partnership brings the capabilities of this 
unique national resource to regional telecommunications users.

     The goals of the program reflect national priorities in 
advancing technology development and promoting U.S. competitiveness 
in international markets.  The program will conduct technical 
verification experiments to prove the high-risk technology and a 
balanced set of experiments which evaluate the potential 
applications of the technology.

     Experiments have been selected that meet these goals and 
challenge the ACTS system.  The results of these investigations 
could yield numerous benefits to business, health care, education, 
national defense, and emergency/disaster relief and advance the 
technology in high data rate communications.  The following 
describes ACTS's contribution to these areas and candidate 
experiments.  (The experiments listed below have been officially 
accepted into the ACTS Experiments Program at press time.)

Business Advantages

     Communications is an essential element of any community's 
infrastructure, but in business it can be the factor that promotes 
profit or inhibits growth.  Expanded communication capacities such 
as fax machines and electronic information networks have 
revolutionized the way the business is conducted around the world.  
The ACTS Experiments Program provides an opportunity for business to 
test new technologies that may lead to more efficient ways to 
operate and create new services.

     With the advent of ACTS, a new generation in communications 
technology will bring benefits to business.  ACTS-type technologies 
will increase efficiency and lower the cost of business 
communications by enabling real-time communications and the use of 
smaller satellite dishes.  It can augment fiber-optic networks to 
extend communications capacity to remote areas, creating new 
telecommunications users and enhancing the "information 
superhighway" with Earth-space linkages.


EXPERIMENTS

     The ACTS Program has developed and will validate, by flight 
testing, high risk advanced communication satellite technologies.  
The validation of these technologies is to be accomplished through 
the ACTS Experiments Program.  The ACTS flight and ground systems 
will be made available to the public and private sectors (industry, 
universities and government agencies) for evaluation, 
experimentation and demonstration of key technologies and their 
applications after launch.  A formal 2-year Experiments Program 
currently is planned, including:  

   *  demonstrate the commercial viability and market acceptability
      of new voice, data and video networks and service with ACTS

     * verify the on-orbit performances of the advanced technology
     	 components of the ACTS flight system

     *  demonstrate and evaluate the system networking aspects of the
        switching and processing technology 

     *  characterize the Ka-band transmission medium and develop
        techniques to combat signal fade and attenuation

     To date, some 60 experiments have been approved to use the ACTS 
system.  These experiments represent 86 principal investigators and 
co-investigators from over 61 different organizations.  

     The following table breaks down the application experiments 
category into a number of sub-categories and lists the number of 
experiments currently planned for each.

Application Experiments Categories

Business Networks	7
Medical	3
Integrated Services Digital Network	4
Public Switched Network	3
Education	1
Video/Teleconferencing	1
DOD Strategic/Tactical	2
Gigabit Networks	3
High Definition TV	1
Supervisory Control and Data Acquisition	1
Land Mobile	6
Aeronautical Mobile	1
Science	3
Network Protocol	1

TOTAL	37


American Express
Availability Comparison Between Ku and Ka Satellite Technologies

     American Express is interested in testing the ACTS very-small 
aperture terminal (VSAT) technology to determine if it will be a 
viable future business option for transactions.  ACTS will operate as 
a data channel between facilities in Phoenix, Ariz., and Mexico City, 
Mexico.  American Express has an existing Ku-band link between these 
sites and wants to compare the performance of the ACTS Ka-band T-1 
VSAT (capable of higher data rates, 1.544 Mbps, with a smaller 
terminal) to its current system.  Contact:  Thomas Marshall, 602/492-
4321.

Southern California Edison
Low Cost SCADA Network
Affiliated Organizations:  Weber State University, Wasatch Research

     Southern California Edison (SCE) is working with NASA Lewis 
Research Center to build and test an ultra-small aperture terminal 
(USAT) that operates at Ka-band for use in a supervisory control and 
data acquisition (SCADA) network.  Weber State University will 
conduct the tests of the terminal with both Ku- and Ka-band antennas 
and will compare performance.

     The spotbeam antenna technology of ACTS makes it possible to use 
smaller terminal apertures.  SCE is investigating the Ka-band USAT to 
determine its suitability for use with electric utilities and other 
industries.  Contact:  Dr. Roosevelt Fernandes, 818/812-7305.

Ohio University
Disaster Recovery, Backup, and Communications Augmentation Experiment 
Using ACTS
Affiliated Organizations:  Huntington Bank, SUNGARD Recovery 
Services, Inc., Unisys Corporation, Ascom Timeplex, Inc.

     Ohio University will conduct tests with ACTS to help Huntington 
Bank recover from a "simulated" natural or other disaster, thus 
protecting it against a total loss of communications.  ACTS will 
transmit financial data such as deposits, account balances and 
transfers of funds.  The experiment will determine the reliability of 
the data link and the ability to switch over to a backup 
communications system within an acceptable period of time as well as 
the economical advantages of using such a system.  Contact:  Dr. Don 
Flournoy, 614/593-4866.

COMSAT World Systems
Prototype INTELSAT Operations

Affiliated Organization:  INTELSAT

     This experiment will provide operational experience with ACTS 
technology to potential service providers, earth station owners, and 
users, emphasizing the use of Ka-band and onboard signal processing.  
The reliability and transmission quality of Ka-band will be compared 
with C- and Ku-bands to determine feasibility of future use.  
Contact:  A.M. Goldman, Jr., 202/863-6601.

Jet Propulsion Laboratory
ACTS Aeronautical Experiment
Affiliated Organizations:  Air Force Rome Labs, Boeing Defense and 
Space Group, GE Electronics Laboratory, Texas Instruments

     The Jet Propulsion Laboratory (JPL) will demonstrate a 4.8 kbps 
voice and data link between an aircraft and a fixed terminal using 
phased-array antennas.  This experiment will evaluate ACTS spotbeam 
technology, the ACTS Mobile Terminal (AMT), and phased-array antennas 
for use in aeronautical communications.  Aeronautical communications 
could be an important new growth area in the telecommunications 
industry.  Contact:  Brian Abbe, 818/354-3887.

Baseline Land-mobile Experiments

     JPL will conduct multiple mobile communications experiments 
demonstrating various applications involving voice, data, and slow-
scan video.  They will evaluate the commercial viability of system 
concepts and perform propagation measurements.  The main purpose is 
to evaluate K/Ka-band feasibility for mobile applications.  Contact:  
Mr. Tom Jedrey, 818/354-5187.

Dataflow Systems
Direct-to-Premises ACTS-based Video Services
Affiliated Organizations:  University of California-Berkeley, 
Mississippi State University

     Dataflow Systems will investigate two-way, direct-to-premises 
static and motion video services with ACTS, based on low cost, low 
power workstations.  Such services are needed to communicate images 
between offices during normal business operations or in emergency 
situations.   Some of the possible applications include:  multimedia 
conferencing between remotely located CAD/CAE design teams, doctors 
in surgery, lawyers in court, and industrial process control teams.  
Also, use of ACTS would enable on-demand and dynamic database 
browsing and copying.  Contact:  Dr. Vason P. Srini, 415/527-7183.

Public Broadcasting Service
High Definition Television and Video Demonstration

     The Public Broadcasting Service (PBS) will use ACTS to transmit 
high definition television (HDTV) and digital video signals from PBS 
to member stations.  Member stations could then distribute the 
signals via terrestrial transmitters or cable TV.  PBS will be 
experimenting with the High Data Rate terminal -- the only ground 
station available capable of transmitting HDTV signals.

     In another test, PBS would transmit via ACTS from member 
stations to a small area to demonstrate the feasibility of local 
direct broadcast satellite service (DBS) within a single city or 
market region.  Contact:  Mr. Carl Girod, 703/739-5483.



   COMSAT Laboratories
Integrated Services Digital Network (ISDN) Experiments

     In this experiment, COMSAT will demonstrate the ability of 
satellite communications to provide state-of-the-art commercial 
telecommunications services.  The experiment is designed to test the 
viability of providing a variety of services and teleservices via 
ISDN using an ACTS-type system.  COMSAT will measure the performance 
of the ACTS ISDN technology and its network capabilities.  Contact:  
Moorthy Hariharan, 301/428-7747.

University of Florida
Narrow band ISDN Applications Using ACTS

     The relationship between ISDN and satellites is complementary.  
ISDN provides satellite networks with a single access point into 
multiple ground networks.  On the other hand, satellite systems 
provide increased geographical coverage for ISDN.  ACTS's advanced 
features enhance this relationship by increasing flexibility of 
connectivity, network efficiency, and quality of service.

     The University of Florida will conduct three narrow band ISDN-
related investigations which can be implemented using ACTS:  video 
teleconferencing, performance evaluation of High-Level Data Link 
Control (HDLC) protocol over a Ka-band satellite channel (which will 
study the effect of rain fade on this protocol with respect to its 
various control functions such as addressing, frame numbering, error 
recovery, and flow control), and Local Area Network interconnection.  
Contact:  Dr. Haniph A. Latchman, 904/392-4950.

NASA Lewis Research Center
North American ISDN Users' Forum (NIUF) Demonstration
Affiliated Organizations:  A consortium of users and telephony 
industry, including: Bellcore, Regional Bell Operating Companies, 
AT&T

     This experiment will demonstrate ACTS ISDN services to NIUF 
members.  It will involve the use of a T-1 VSAT transportable link 
back to Lewis Research Center, JPL, and other ACTS ISDN transportable 
nodes.  The primary application demonstrated will be PC-based 
multimedia teleconferencing.  Contact:  Tom vonDeak, 216/433-3277.

NBC
Satellite News Vehicle (AMT) Experiment
T-1 VSAT Backhaul Experiment
Affiliated Organization:  JPL

     NBC will investigate mobile and fixed terminal capabilities for 
providing increased communications for people in the satellite news 
industry, specifically while enroute to and from news sites.  The 
experiments will determine how many "hops" can be made between points 
before image quality degrades beyond acceptable levels.

     The fixed experiment involves using several T-1 VSATs to provide 
multiple "hop" communications, transmitting the same images from 
point to point between different broadcast locations.  The mobile 
experiment will evaluate the ACTS and AMT technologies for remote 
communications purposes, e.g., from a news bureau to a satellite news 
vehicle.  Contact:  Robert Sisko, 212/664-6186.

IDB Communications Group
Satellite News Gathering Land-Mobile Experiment/Demonstration
Affiliated Organization:  JPL

     IDB Communications is interested in showcasing the ACTS and AMT 
technologies for remote broadcast purposes.  This 
experiment/demonstration will be a live transmission of IDB 
Communications' network-fed broadcast via ACTS.  It will occur at the 
National Association of Broadcaster's Convention in 1994.  Contact:  
David Anderson, 213/240-3726.

Bellcore
Experimentation with Satellite-based Personal Communications Services 
(PCS)
Affiliated Organization:  JPL

     The goal of this research effort is to demonstrate the 
capabilities of satellites for enhancement of ground-based personal 
communications voice and data services.  The experiment will 
determine the ways in which local exchange network providers can 
interface to wireless service providers and the kinds of services 
that should be offered.

     The applications being investigated include:  two-way messaging, 
delivery of personalized information services, use of satellites to 
alert nomadic end users of incoming telephone calls.  It will also 
test the combined capability of satellites plus Global Positioning 
System service to locate nomadic end users, update network databases, 
and route calls and/or messages to their current location.  Contact:  
Richard Wolff, 201/829-4537.

Florida Atlantic University
ACTS Wide Bandwidth and Video Compression Experiments

     The primary goal of this experiment is to demonstrate the use of 
ACTS for commercial video data transmission.  Florida Atlantic 
University will use video compression techniques developed by the 
University and will test the reliability and feasibility of ACTS to 
provide this commercial service.  Contact:  Dr. Henry Helmken, 
407/367-3452.

Martin Marietta Astrospace
Business Telecommunications for Potential Customers

     Martin Marietta Astrospace will be allowing potential customers 
to evaluate the Ka-band frequency for business communications.  
Martin Marietta has purchased a ground station for its facility in 
East Windsor, N.J., in order to experiment with ACTS.  It is 
identifying various areas for investigation.  Contact:  Frank 
Gargione, 609/490-2337.




   HEALTH CARE ADVANTAGES

     Availability of quality health care is a primary concern to 
people everywhere.  When a patient is not able to get to health 
facilities or when specialists are not available for consultation, 
precious time is wasted.  Improved and expanded telecommunications 
can help overcome distance barriers, improve upon local facilities, 
and extend medical services to more people, while maintaining 
reasonable costs.

     The ACTS Experiments Program is working with medical personnel 
around the country to test delivery of health care services to remote 
locations and to demonstrate the use of more sophisticated mobile 
communications.  ACTS will transmit images and information to 
physicians and specialists for use in diagnoses.  High-resolution 
medical imagery from X-rays, MRIs, or CT scans can be sent to another 
location for review by a consulting physician.  The ACTS Mobile 
Terminal (AMT) will also be used to transmit patient data from 
emergency vehicles while en route to a hospital.

EXPERIMENTS

Mayo Foundation
Application of the NASA ACTS Satellite System to the Practice of 
Medicine in an Integrated Group Practice
Affiliated Organizations:  U.S. Army Medical Diagnostic Imaging 
Support

     The Mayo Foundation will be using ACTS to investigate 
communication techniques which may eventually allow large medical 
centers to provide supporting medical services to small and medium-
sized medical facilities in small towns and rural areas.  The 
objective of the experiment is to demonstrate that the provision of 
quality medical diagnostic and information services to remote 
facilities can be cost effective and timely.

     It has become essential to be able to communicate and transmit 
data from one medical facility to another to enhance the quality of 
care for individual patients and to seek consultation from experts 
who may be at a distant location.  Mayo will be investigating a 
variety of medical applications including image, data, and voice 
transmission.  They will use ACTS to transmit in real-time medical 
imagery and other patient test information for diagnosis.  The on-
demand flexibility, wide bandwidth, ISDN and high data rate 
capabilities of ACTS could solve many medical outreach problems.  
Contact:  Dr. Robert Hattery, 507/284-9425.

Georgetown University School of Medicine
Remote Radiology

     In this experiment, Georgetown University will transmit magnetic 
resonance images (MRI) and radiological images from Tripler Army Base 
in Hawaii to Washington, DC.  Tele-education will also be provided 
for radiologists and radiologists-in-training.  The experiment may be 
expanded to include transmission to South America.  Contact:  Dr. 
Seong K. Mun, 202/687-5990.


NASA Lyndon B. Johnson Space Center
Application of Small Earth Stations in Conducting Telescience and 
Telemedicine
Affiliated Organizations:  Krug Life Sciences, University of Colorado

     Johnson Space Center will use ACTS to test the utility of 
advanced satellite technology for conducting telemedicine, 
telescience, video conferencing, and high resolution image transfer.  
Specifically, the experiment will generate images of the interior of 
the eye.  The images will then be transmitted to another location via 
ACTS for analysis.  Contact:  Dr. Gerald Taylor, 713/280-0469.

EMSAT:  Advanced Technology for Emergency Medical Services
Emergency Medicine Land-Mobile Satellite Experiment (EMSAT)
Affiliated Organizations:  JPL

     EMSAT will evaluate the feasibility of mobile satellite 
communications for pre-hospital communications.  Experiment 
objectives are to demonstrate and assess the transmission and 
reception of satellite digital voice for two-way, pre-hospital 
communications, one-way transmission of patient data from field 
paramedics to the base hospital, and telemetry of patient assessment 
data to the base hospital.  Factors that affect pre-hospital 
satellite communications will be studied.  
Contact:  Bruce P. Jackson, 818/842-0207.

University of Washington
Mobile Radiology Image Transfer
Affiliated Organization:  GE Medical Systems

     This experiment will link a mobile Computed Tomography (CT) or 
Magnetic Resonance Imaging (MRI) van to the Department of Radiology 
at the University of Washington Medical Center.  The mobile van will 
transmit digital medical images (while stationary) from various 
locations in the state of Washington.  This investigation will allow 
for quality control and for diagnostic consultation and 
interpretation of the remotely obtained images at a major university 
medical center.  This use of ACTS demonstrates a practical medical 
application of teleradiology from remote locations to medical 
centers.  Contact:  Dr. Stephen J. Carter, 206/685-2693.

ACTS/AMT Telemedicine Experiment
Affiliated Organization:  JPL

     This experiment involves the transmission of CT and MRI images 
to the University of Washington via ACTS using a portable computer 
with the AMT, the fixed terminal located at NASA Lewis Research 
Center (LeRC), and a telephone line from LeRC to the University of 
Washington Medical Center.  The received images will be filmed with a 
laser camera and compared with original films.  The transmissions 
will be performed during various weather conditions and at multiple 
locations throughout rural Washington state.  Contact:  Dr. Stephen 
J. Carter, 206/685-2693.




   Lister Hill National Center for Biomedical Communications 
National Library of Medicine
National Institutes of Health
VAMA:  VSAT Access to Medical Archives
Affiliated Organization:  University of California at San Francisco, 
School of Medicine

     ACTS offers the opportunity to experiment with techniques and 
procedures suitable for a communications environment that allows 
real-time access to critical medical information.  Current access to 
medical archives at the National Library of Medicine is achievable 
through INTERNET.  However, the transmission rate is such that real-
time interaction and selection of information is not possible.  

     A set of experiments will test prototype systems for the rapid 
transfer of medical images across widely-separated geographical 
areas.  Two possible experiments:  test a prototype medical 
information system to provide remote access to a national medical 
database in real time and demonstrate a system to rapidly and 
accurately transfer a large volume of uncompressed digital x-ray 
image files.  Contact:  Mr. Rodney Long, 301/496-4496.


LONG DISTANCE EDUCATION AND TRAINING

     Education and training are key to increased knowledge and 
productivity.  In this era of changes in the economy and the 
workplace, students and workers, with increasingly limited time and 
resources, will need to have better access to educational and 
training facilities.  ACTS-type technology can provide real-time, 
more advanced communications capability to the classroom or the 
workplace.  It can also tap into information networks faster and 
transmit that information quicker than current communications 
systems.

     Some ACTS experimenters will be investigating the use of long-
distance, real-time, interactive communications to educate people 
outside of major learning institutions.  They will test the 
capability of ACTS to deliver instruction to interested students in 
different areas in the United States and in South America.  Other 
experimenters will use ACTS to provide special training.  ACTS-type 
service could create new educational networks.


EXPERIMENTS

Georgetown University
Georgetown Technical Hemispheric Intercultural Network for Knowledge 
(G-THINK)
Affiliated Organizations:  Inter-American Development Bank, IBM, 
Citibank, Martin Marietta Astrospace, Loral, Andres Bello University, 
Catholic University, Javeriana University, Latin America Institute of 
Doctrinal and Social Studies, Sophia University

     Georgetown University will investigate the viability of two-way, 
interactive distance learning, involving programs that are medical, 
scientific, or research in nature.  ACTS will be used to demonstrate 
distance education to four South American sites in Columbia, Ecuador, 
Venezuela, and Chile.

     Georgetown will also conduct distance education projects in the 
United States in the areas of medicine, business, teleradiology, 
library database access, veterinary medicine, and remote sensing.  
Contact:  Rev. Harold C. Bradley, S.J., 202/687-3455.

NASA Kennedy Space Center
Distance Learning in the Area of Hazardous Materials and 
Environmental Safety
Affiliated Organizations:  Lockheed Space Operations Company, 
University of Central Florida

     This experiment involves distance learning in the area of 
hazardous materials and environmental safety.  ACTS will link Dryden 
Flight Research Facility, Calif., and Kennedy Space Center, Fla., for 
approximately 10 hours of training to Lockheed employees.  The 
experiment consists of distance learning classes using lecture, 
graphics, and videotape.  It will test the quality of video and audio 
and effectiveness of Ka-band for distance learning.  Contact:  Darwin 
V. Brown, 407/867-7293.

Florida Agricultural and Mechanical University
Distance Learning

     ACTS will be used to link the College of Pharmacy at Florida A&M 
University (FAMU) in Tallahassee with the FAMU Clinical Training Unit 
located in Miami and allow for the instruction of students.  The 
experiment will involve two-way voice and video transmission and will 
be divided into two 16-week and one 13-week segments.  Contact:  
Johnnie L. Early, 904/599-3301.


IMPROVED NATIONAL DEFENSE AND EMERGENCY/DISASTER COMMUNICATIONS

     In the Persian Gulf war and the aftermath of Hurricane Andrew, 
the United States reaffirmed the value of advanced military and 
disaster communications.  Secure and reliable communications provided 
necessary advantages to American troops in executing quick and 
successful air and ground attacks, while minimizing casualties.  In 
severe contrast, lack of immediate and adequate communications 
capability severely hampered the relief efforts in Florida and 
Louisiana.

     Experimenters with ACTS will gain insight into improved military 
and emergency/disaster communications by testing new concepts.  The 
use of the ACTS Mobile Terminal can restore communications capability 
immediately.  ACTS T-1 VSATs can be used to restore damaged points 
within the Public Switched Network.

     Military and emergency communications can benefit from the real-
time, higher communications capacity demonstrated by the ACTS system.


EXPERIMENTS

National Communications System
Public Switched Network (PSN) Restoration
PSN Trunking
Isolated User Access
Secure Mobile Communications
Affiliated Organizations:  MITRE Corporation

     The National Communications System (NCS) experiments will 
demonstrate the capability to restore or augment communication 
networks.  It is the responsibility of the NCS to coordinate the 
planning for and provision of communications services to a set of 
National Security/Emergency Preparedness (NS/EP) users.  NCS 
initiated the Commercial SATCOM Interconnectivity (CSI) program in 
1983 in response to a Presidential directive stating that CONUS-based 
commercial satellite communication resources should be exploited to 
augment and restore Government communications capabilities during 
times of emergency.  ACTS will be used to investigate new advanced 
satellite communications technologies.

     The first three experiments examine restoration of the PSN when 
disrupted. The first restores communications at the point where loss 
of connectivity occurs or augments existing capability when needed.  
The second experiment provides point-to-point trunking via ACTS for 
NS/EP users when disruption occurs in the PSN inter-exchange carrier 
switches.  The third experiment will demonstrate ACTS's ability to 
communicate with isolated users by restoring communications between 
local carriers in the PSN and inter-exchange carrier switches.  The 
final experiment utilizes the AMT capability to restore 
communications in areas affected by disaster.  Contact:  Mr. Frank 
Dixon, 
703/692-0540.

U.S. Army Space Command
Army ACTS Experiments
Affiliated Organizations:  Combined Arms Center, Department of the 
Army/Army Space Institute, Laboratory Command/Army Space Technology 
Research Office, U.S. Army Communications Electronics Command, U.S. 
Army Information Systems Engineering Command, U.S. Army Future Battle 
Lab, U.S. Army Medical Diagnostic Imaging Support

     The Army ACTS experiments will be incorporated into the Army 
Space Demonstration Program which demonstrates space systems 
capabilities to support AirLand Battle Doctrine.  The Army will use 
ACTS to overcome various operational communications shortfalls.  A 
complete set of verification experiments will be conducted to 
evaluate ACTS technologies and interactions with ground communication 
systems.  The experiments will explore a variety of uses including 
video teleconferencing; transfer of large imagery, 
geographic/meteorological information, logistics, and medical 
databases; remote training; transmission of video, voice and data to 
the field; and testing of mobile communications.  Contact:  Pete 
Cafaro, 719/554-8717.


   U.S Army Topographic Engineering Center
Use of ACTS for Communicating Differential GPS
Affiliated Organization:  Rockwell International

     U.S. Army Topographic Engineering Center (USATEC) is conducting 
an experiment using the Global Positioning System (GPS).  GPS uses 
satellite signals to calculate a position on earth and is subject to 
several sources of error.  These errors remain relatively constant 
within a specific region, and a set of corrections can be generated 
at one location and applied to another.  USATEC via ACTS will 
transmit these corrections to users in real-time.  They will analyze 
time delay, transmission quality, bit error rate, and cost and 
convenience of terminal location and satellite acquisition.  Contact:   
Andrew Austin, 703/355-2765.

U.S. Army Research Labs
Integrated Services Digital Network (ISDN) via Satellite
Affiliated Organization:  Georgia Tech Research Institute

     This experiment evaluates ACTS' ability to provide ISDN 
connectivity among a geographically-dispersed population of end 
users.  It will provide real-time networking of ISDN users via 
satellite and multimedia desktop video teleconferencing.  The ACTS 
system will be compared to a terrestrial DoD ISDN baseline system.  
Contact:  Dr. Jay Gowens, 404/894-3137.


EXPANDING SCIENTIFIC RESEARCH NETWORKS

     Scientific research can be greatly facilitated and augmented by 
improved communications capability.  The majority of scientific 
research is conducted in remote areas that are not accessible by 
modern transportation or fiber-optic cable.  With ACTS-type 
technologies, researchers could gain access to remote databases that 
contain needed information.  Researchers would also have the ability 
to communicate in real-time with other scientists in the field to 
obtain results from experiments or to consult on a problem.  Mobile 
communications could benefit researchers by providing a transportable 
link to laboratories or universities.

     Experimenters in the ACTS Program will be investigating the use 
of new communication techniques in conducting scientific research.  
From operating remote laboratories to simply transmitting needed 
information from Arctic climates, ACTS can improve the way scientists 
operate and make it easier to distribute scientific results.


EXPERIMENTS

New Mexico State University
Real-Time, High-Bandwidth Data Links

     ACTS will provide a high-bandwidth, real-time link to gain 
access and control of an astronomy telescope located at the Apache 
Point Observatory in south-central New Mexico by a remote user within 
the continental United States.  The user will not have to be on-site 
during the observation period.  The present mode of access to the 
observatory is through commercial, land-based telephone lines.

     New Mexico State University will look to ACTS to give the user a 
"touch and feel" for remote access and control and to provide the 
high-rate capacity needed for data transmission from a new, deep-sky 
telescope which will produce continuous, digital data from an array 
of sensors.  They will also test ACTS for non-real-time data 
networking to support observatory management, database sharing, 
computer conferencing, and similar services for the science 
community.  Contact:  Dr. Stephen Horan, 505/646-5870.

National Science Foundation
Antarctic Researcher Support
Affiliated Organization:  University of California-Santa Barbara

     ACTS would provide an advanced communications link between 
Palmer Station in the Antarctica and U.S. laboratories.  It would 
also provide access to the INTERNET and high quality voice 
communications, allow rapid and relatively large transfer of data, 
and permit access to high data rate satellite information such as SAR 
sea-ice images.  It would also allow for off-station logistics and 
scientific support, database management, data analysis, and open 
Palmer to as yet untapped educational opportunities.  ACTS would 
contribute to increased researcher productivity thereby decreasing 
the number of researchers needed on-site and would provide a greatly 
needed link to the outside world from Palmer's remote location.  
Contact:  Dennis Peacock, 202/357-7894.

George Washington University
Supercomputer Networking Applications
Affiliated Organizations:  COMSAT Laboratories, Cray Research, NASA 
Goddard Space Flight Center (GSFC), Jet Propulsion Laboratory

     George Washington will use ACTS to demonstrate the ability of 
satellites to support high data rate communications such as 
distributed supercomputer applications.  JPL will be able to access 
GSFC's supercomputer facilities to enable oceanic/atmospheric 
modeling.  Also, supercomputers will be linked to accelerate weather 
forecasting.  The experiments can simulate Earth and space science 
processes, create real-time visualization of the data, and distribute 
the data through a wideband data communications network.  Contact:  
Dr. Burt Edelson, 202/994-1431.

Pacific Space Center (PacSpace) and University of Hawaii
Advanced Applications to Validate ACTS Technologies
Affiliated Organizations:  Argonne National Laboratory, Hawaii Space 
Development Authority

     The State of Hawaii faces unique communication problems caused 
by distance.  PacSpace will utilize ACTS to help solve some of these 
problems and to perform a range of experiments.  They will use the 
high capacity of an ACTS ground station to support other on-going 
programs at the University of Hawaii, involving image processing and 
management, high performance computing and communications, oceanic 
research, and integration of advanced communications networking.  
Experiments will test the practicality of remote access to large 
image databases for scientific, military and educational information.  
They also will test transfer of scientific research data to central 
facilities.  Contact:  Dr. David Yun, 808/533-1539.


ADVANCING TECHNOLOGIES AND U.S. COMPETITIVENESS

     The ACTS Program has and will continue to contribute to the 
development of advanced technologies.  Since ACTS will operate at the 
Ka-band frequency, off-the-shelf Ka-band components are now 
available.  The spotbeam and onboard switching and processing 
technologies developed for ACTS have already in part been adapted for 
use in planned communication systems.  American research efforts in 
high definition television (HDTV) and in integrated services digital 
networks are also being advanced by ACTS technology development.  
Smaller ground stations that transmit at higher data rates have been 
created for use with ACTS.  The proving ground for all of these 
technologies is the ACTS Experiments Program.  The testing and 
performance of the technology could yield important results that will 
impact future communication systems in years to come.

     ACTS technology not only advances the state-of-the-art but also 
strengthens U.S. competitiveness in the international 
telecommunications market.  Since 1982, the U.S. share of the 
communications satellite and equipment market has shrunk in the face 
of increased competition from European and Japanese companies.  NASA, 
in conjunction with industry, government and academia,  developed the 
ACTS and its associated ground system to advance the U.S. competitive 
position in technologies expected to be widely used in the 21st 
century.

EXPERIMENTS

Advanced Research Projects Agency
High Data Rate Terminal Development and Experiments

     The Advanced Research Projects Agency (ARPA), in a cooperative 
effort with NASA, has sponsored the development of the High Data Rate 
(HDR) terminal as part of a satellite research testbed network using 
ACTS and in support of the federal High Performance Computing and 
Communications (HPCC) program.

     The HPCC was developed as a multi-agency effort for the purposes 
of extending U.S. technological leadership in high performance 
computing and computer communications and of providing wide 
dissemination and application of these technologies.

     One element of the HPCC program is the development of technology 
for wide area gigabit (one billion bits per second) data networking.  
ARPA has the responsibility for coordinating the multi-agency 
research effort to achieve this capability.  Also, ARPA has strong 
interests in investigating very high speed satellite/terrestrial 
communications for defense applications.  NASA believes that 
satellites can render significant service in hastening the 
development of high data rate applications for commercial and 
government use.  

     In order to achieve mutual goals, ARPA and NASA supported the 
development of the HDR terminal and experiments to challenge network 
capabilities and promote the state-of-the-art in this area.  The HDR 
experiments are intended to demonstrate new capabilities and the 
functionality of high-speed communications.

     The ARPA HDR experiments will investigate the linking of 
satellite and fiber networks, the real-time user interaction with 
complex climate models created with supercomputer visualization, 
military applications, and the distribution of medical imagery.  
Experiment collaborations are currently being developed with:

Ohio Supercomputer Center
Public Broadcasting Service
National Center for Atmospheric Research
U.S. Army Future Battle Lab
Army High Performance Computer Research Center
Mayo Clinic
Georgetown University
University of Hawaii

Contact:  Paul Mockapetris, ARPA, 703/696-2262.

National Telecommunications and Information Administration (NTIA)
Institute for Telecommunication Sciences
Quantify ACTS End-to-End Communication System Performance

     The primary objective of NTIA's experiment is to measure and 
quantify the end-to-end digital communication system performance of 
ACTS from the end user's perspective.  The experiment will also 
provide documented knowledge of advance communication satellite 
system performance.  These measurements will be used to establish a 
baseline measure of performance of ACTS.  This quantification of the 
ACTS system will enable performance comparisons of advanced 
satellites with other telecommunications technologies, e.g., public 
data networks and conventional communication satellite systems.

     This performance data will be used by NTIA/ITS to help develop 
national and international telecommunication standards that will 
strengthen the use of advanced communication satellites in 
telecommunication networks.  Future networks may incorporate 
satellites in a hybrid network design where a satellite provides 
back-up and restoration services as well as thin-route and mobile 
communications.  Contact:  Marjorie Weibel, 303/497-3967.

Motorola, Inc.
BBP Transmit Window Characterization
High Burst Rate Modem Evaluation
Coding Gain Evaluation

     Motorola will be conducting a series of experiments to 
technically challenge the ACTS system.  In the first experiment, it 
will measure the times of data arriving at the ground station while 
varying transmit time in order to evaluate ACTS link erosion due to 
orbital variations and clock accuracies.

     The second experiment will test Motorola's modem technologies 
through the ACTS microwave switch matrix channel which is capable of 
higher data rates.  Motorola will use advanced modulation techniques 
and coding to maximize bit error rate performance.

     The last experiment will investigate the effect of coding on 
ground station transmissions.  Data will be transmitted in coded and 
uncoded modes, and bit error rates will be measured.  The data will 
be evaluated to determine the advantage realized by coding 
techniques.  Contact:  Kerry Lee, 602/732-2299.

COMSAT Laboratories
Demonstration of Advanced Networking Concepts
Affiliated Organization:  INTELSAT

     The trend toward utilizing smaller ground station antenna sizes 
and increasing the use of higher frequency bands has focused 
attention on methods for overcoming rain-induced degradation of the 
satellite signal.  One method is to integrate a number of VSATs 
through a Metropolitan Area Network (MAN) into a Wide Area Diversity 
(WAD) Network.

     The objective of this experiment is to identify whether Ka-band 
VSATs can achieve error performance and availability levels defined 
for an international ISDN connection, despite the propagation 
conditions in these bands, based on the networking method described 
above.  Successful penetration of satellite-distributed 
communications services into existing and new markets hinges on two 
factors:  economics and quality of service.  Economy can be achieved 
through use of smaller Earth stations.  Availability is achievable 
through site diversity.  COMSAT Laboratories will use ACTS to test 
this theory.  Contact:  Dr. Asoka Dissanayake, 301/428-4411.

Hopping Beam TDMA Operation Observations

     One of the most advanced features of ACTS is the combination of 
satellite baseband circuit switching, Time Division Multiple Access 
(TDMA), and spotbeam hopping.  This experiment will test the 
operation of these technologies and will evaluate receive and 
transmit acquisition performance under normal and worst case 
operational conditions.  Contact:  Robert Ridings, 301/428-4264.

Corporate Computer Systems
High Quality Audio (AMT) Experiment
Affiliated Organizations:  JPL, CBS Radio

     Two mobile satellite communications experiments are planned for 
ACTS.  The first involves interfacing the AMT with a MUSICAM 
Perceptual Coder and operating this system at coded 64 kbps to 
demonstrate high quality mono audio transmission.  The second 
experiment interfaces the equipment with the AMT and operates at 
uncoded 128 kbps.  The experiments also involve testing of an 
algorithm built into the processing capabilities of the MUSICAM 
Perceptual Coder.  The audio coder will monitor the received signal 
and vary the "amount of coding" necessary to maintain the link.  
Contact:  Dr. Larry Hinderks, 908/946-3800

MITRE Corporation
Protocol Evaluation for Advanced Space Data Interchange

     MITRE will study the suitability of standard data communication 
protocols for future generations of communications satellites.  The 
hopping spotbeam technology of ACTS, together with T-1 VSATs 
providing direct service to experimenters, suggests that the current 
method of payload data distribution, using a "bent-pipe" combined 
with a data distribution hub on the ground (the current Tracking and 
Data Relay Satellite System method), could be replaced or augmented 
by direct data distribution to users.

     ACTS will be tested and data communication protocols evaluated 
to determine feasibility of an ACTS-type system for data 
distribution.  Contact:  Quoc Nquyen, 703/883-5674.

New Jersey Institute of Technology
Traffic Modeling, Channel Characterization, Coding, and Modulation on 
the ACTS
Affiliated Organization:  Martin Marietta Astrospace

     The New Jersey Institute of Technology will perform a group of 
technology verification experiments.  It will test various traffic 
models for video teleconferencing data.  It also will investigate the 
performance of ACTS at Ka-band and will test several coding and 
channel equalization methods.  Contact:  Dr. Y. Bar-Ness, 201/596-
3520.

University of Maryland Center for the Commercial Development of Space
Frame Relay Experiments over ACTS:  LAN Interconnection Services
     Affiliated Organizations:  Comsat Labs, National 
Telecommunications and Information Administration, National 
Information Technology Center, and University of Colorado

     The University of Maryland will demonstrate fast packet 
switching communication using the ACTS T-1 VSAT network as applied to 
interconnection of Local Area Networks (LANs).  The experiment will 
measure the bit error rate and performance of congestion control 
algorithms and confirm ACTS Frame Relay conformance to performance 
requirements.  It will also demonstrate the capability of satellites 
such as ACTS to interconnect geographically dispersed LANs.  
Applications to be tested include file transfer, electronic mail, and 
interactive visualization (X-Windows) between LANs.  Contact:  Dr. 
Anthony Ephremides, 301/405-3641.

NASA Lewis Research Center

On-orbit Spacecraft Dynamics
     This experiment will determine the spacecraft position (angular 
and range) as a function of time with respect to the Master Control 
Station at the NASA Lewis Research Center.  Contact:  Dr. Roberto 
Acosta, 216/433-6640.

Mini Terminal Test Bed (MTTB)
     The goal of this experiment is to develop and test a 
communications technology testbed. The testbed will contain state-of-
the-art Ka-band subsystems and components currently being designed by 
the NASA Lewis Research Center, Space Electronics Division.  The 
experiment will determine the performance of these components for 
possible use in future communications systems.  Contact:  Gene 
Fujikawa, 216/433-3495.

Multibeam Antenna Performance Verification
     This experiment will determine the ACTS on-orbit antenna 
performance and will validate the LeRC Structural/Thermal/RF Analysis 
Program.  Contact:  Dr. Roberto Acosta, 216-433/6640.

Networking Technical Experiment for BBP Operations
     Performance of the ACTS network control system and the adaptive 
rain fade compensation technique will be evaluated.  Contact:  Thom 
Coney, 216/433-2652.

Microwave Switch Matrix and Wideband Transponder Performance 
Evaluation
     LeRC will verify the ACTS Microwave Switch Matrix (MSM) mode of 
operation through all of ACTS transponder paths.  In addition, the 
experiment will verify that the MSM can support reliable high data 
rate communications.  Also, various rain fade compensation algorithms 
will be developed and implemented to explore improved approaches.  
Contact:  Don Hilderman, 216/433-3538.

Communications Link Performance
     This experiment will measure co-frequency interference, adjacent 
frequency interference, adjacent burst interference, and uplink bit 
error rate performance under various conditions.  It will also 
evaluate ground station performance and investigate clock accuracy on 
network performance.  Contact:  Dr. Jon Freeman, 216/433-3380.

ACTS Propagation Studies
     The ACTS Rain Attenuation Prediction Model will be tested to 
verify fade occurrence and duration predictions at ACTS ground 
stations.  The experiment also will demonstrate the capability of 
rain fade compensation algorithms for the NASA Ground Station in 
Cleveland.  Contact:  Dr. Roberto Acosta, 216/433-6640.

Autotrack Control Performance
     This experiment will test and verify the on-orbit antenna 
pointing stability at peak thermal cycles.  Contact:  Dr. Roberto 
Acosta, 216/433-6640.

HBR SMSK Interference Experiment (INTEX)
     LeRC will measure the bit error rate of a transmitted serial 
minimum shift-keyed modulated satellite signal in the presence of 
various types of interfering signals.  Contact:  Robert Kerczewski, 
216/433-3434.

Compressed Digital Video Transmission
     Satellite delivery of compressed digital video will be tested.  
The experiment also will demonstrate the effects of the ACTS system 
on a 25-30 Mbps broadcast quality digital television system while 
evaluating video compression hardware over a real channel.  Contact:  
Wayne Whyte, 216/433-3482.





   ACTS PROPAGATION EXPERIMENTS

     ACTS provides an opportunity to study the characteristics of 
impairments to Earth-space communications at Ka-band (30/20 GHz) 
caused by propagation phenomena and to develop techniques to counter 
them.  Rain is a major impediment to Ka-band communications because 
it causes fades in the satellite signal.  It presents quite a 
challenge to system designers because it causes more severe fades at 
this frequency than in other, lower frequency bands.

     Other phenomena also affect the satellite signal.  Clouds and 
atmospheric gases -- such as water vapor and oxygen -- can also cause 
signal fades.  Tropospheric scintillation (twinkling in the 
atmosphere) is another important factor.  Also, the advent of smaller 
user terminals with their smaller operating margins increases the 
need for propagation data. 

     The ACTS Propagation Program will determine the impairments to 
the satellite signal caused by the various physical phenomena during 
the planned experiment period.  The experiments will:

     *  provide a lasting base of 30/20 GHz propagation data for
        communications
        satellite builders,
     *  collect propagation data for a minimum of 2 years, and
     *  obtain information on the physical processes that cause
        signal impairments.

     Researchers in this field believe that it is necessary to 
conduct measurements over longer periods of time to obtain valid 
information concerning the effects of propagation phenomena on 
satellite signals.  ACTS provides a unique opportunity to measure the 
effects at Ka-band for a statistically adequate time period and in 
different climatic areas for which no measurements currently exist.

     Lewis Research Center issued a NASA Research Announcement to 
solicit experiments to expand the current base of knowledge 
concerning propagation effects on Ka-band satellite signals.  NASA 
sponsored the development and production of the ACTS Propagation 
Terminal for experimenters to use to conduct these measurements.  The 
selected experiments consist of two defined classes.

CLASS I 	In situ measurements using the propagation terminal to 
obtain radio wave propagation data at 20 and 28 GHz using 
beacons on ACTS as the signal source.  Propagation 
terminals will be located in various climate zones in North 
America to gather this data.


EXPERIMENTS

Colorado State University
Ka-band Propagation Studies Using ACTS Propagation Terminal and the 
CSU-CHILL Multiparameter, Doppler Radar
Contact:  V. N. Bringi, 303/491-5595.

University of Alaska
ACTS Propagation Measurements in Alaska
Contact:  Dr. Charles E. Mayer, 907/474-6091.

COMSAT Laboratories
ACTS Uplink Transmit Power Control Measurement Experiment
Ka-band Propagation Measurements Experiment Using the ACTS Spacecraft
Contact:  Dr. Asoka W. Dissanayake, 301/428-4411.

Stanford Telecommunications
A Proposal for ACTS Propagation Experiments
Contact:  Dr. Louis J. Ippolito, 703/438-8069.
Affiliated Organizations:  New Mexico State University, NASA HQ Code 
O

University of Oklahoma
Rain Attenuation Statistics for the ACTS Propagation Experiments for 
Central Oklahoma
Contact:  Prof. Robert E. Crane, 405/325-4419.

University of British Columbia
ACTS Ka-band Propagation Measurements in a West Coast Maritime 
Climate
Contact:  Dr. M.M.Z. Kharadly, 604/822-2816.

University of South Florida and Florida Atlantic University
Propagation Measurements Using ACTS
Contact:  Dr. Rudolph E. Henning (USF), 813/974-4782 or Dr. Henry 
Helmken (FAU), 407/367-3452.


CLASS II	Measurements using either the ACTS communications channels 
or beacon signals to investigate other aspects of radio 
wave propagation on new communication services, such as 
multipath and blockage effects on mobile communications.


EXPERIMENTS

COMSAT Laboratories
ACTS Wide Area Diversity Experiment
Contact:  Dr. Asoka Dissanayake, 301/428-4411.

John Hopkins University and University of Texas
Land-Mobile Satellite Measurements in Central Maryland and Alaska 
Using ACTS:  Passive Antenna Tracking System and Mobile Receiver 
System
Contact:  Dr. Julius Goldhirsh (JHU), 301/953-5042 or Wolfgard J. 
Vogel (UT), 512/471-8608.

Georgia Tech Research Institute
RF Propagation Effects and ACTS Satellite Channel Characterization 
for Very Small Aperture Terminals
Contact:  Daniel Howard, 404/894-3541.

In another effort Teleglobe Canada will be participating in the ACTS 
Propagation Program, using its own terminal to conduct measurements.  
The experiment effort is not funded by the NRA, but Teleglobe 
Canada's data will be included in the overall Program's propagation 
statistics.

Teleglobe Canada
Measuring Propagation Effects Utilizing ACTS
Contact:  Ara Karahisar, 514/868-8322.




   ORBITING AND RETRIEVABLE FAR AND EXTREME ULTRAVIOLET SPECTROMETER 
- SHUTTLE PALLET SATELLITE (ORFEUS-SPAS)
 
OVERVIEW
 
     The Orbiting and Retrievable Far and Extreme Ultraviolet 
Spectrometer - Shuttle Pallet Satellite (ORFEUS-SPAS) mission is the 
first in a series of missions using the German built ASTRO-SPAS 
science satellite.  The ASTRO-SPAS program is a joint German/U.S. 
endeavor, based upon a memorandum of understanding between NASA and 
the German Space Agency, DARA. 
 
     ASTRO-SPAS is a spacecraft designed for launch, deployment and 
retrieval by the Space Shuttle.  Once deployed from the Shuttle by 
its Remote Manipulation System (RMS), ASTRO-SPAS operates quasi-
autonomously for several days in the Shuttle vicinity.  After 
completion of the free flight phase, the satellite is retrieved by 
the RMS and returned to Earth.  The ASTRO-SPAS program is very cost 
efficient, owing to the versatility and the retrievability of the 
carrier. 
 
     ORFEUS-SPAS is an astrophysics mission, designed to investigate 
very hot and very cold matter in the universe.  The one-meter 
diameter ORFEUS-Telescope with the Far Ultraviolet (FUV) Spectrograph 
and the Extreme Ultraviolet (EUV) Spectrograph is the main payload.  
A secondary, but highly complementary payload is the Interstellar 
Medium Absorption Profile Spectrograph (IMAPS).  In addition to the 
astronomy payloads, ORFEUS-SPAS carries the Surface Effects Sample 
Monitor (SESAM) and the Remote IMAX Camera System (RICS).
 
SCIENTIFIC OBJECTIVES
 
     The ORFEUS-SPAS Mission is dedicated to astronomical 
observations at very short wavelengths, specifically the two spectral 
ranges Far Ultraviolet (FUV, 90-125 nm) and Extreme Ultraviolet (EUV, 
40-90 nm).  This part of the electromagnetic spectrum, which is 
obscured by the Earth's atmosphere for ground-based observations, 
bears among the highest density of spectral lines (especially from 
various states of hydrogen and oxygen), which are emitted or absorbed 
by matter of very different temperature.

     ORFEUS-SPAS will add information to the understanding of the 
life-cycle of stars by observing some of the coldest (several degrees 
above absolute zero) and the hottest (more than one million degrees) 
matter found in our galaxy.  Specific mission objectives are:

*  Investigation of physical parameters in hot stellar atmospheres
*  Investigation of cooling mechanisms of white dwarfs
*  Determination of physical parameters of stellar accretion-
   disks, e.g. mass transfer rates, orbital parameters and
   velocity
*  Shells associated with nova explosions and symbiotic stars
*  Investigation of supernova remnants
*  Investigation of the interstellar medium and potential star
   forming regions.  In particular, determination of distance,
   density and temperature
*  Studies of the intergalactic medium by observations of quasar 
   spectra
 
     Star formation is not yet completely understood.  Stars are, 
however, known to be formed in dense clouds of interstellar gas and 
dust.  Under gravitational contraction, these clouds can become dense 
enough to trigger star formation.  ORFEUS-SPAS will observe the 
ultraviolet absorption lines associated with such clouds.

     More generally, ORFEUS-SPAS will investigate absorption line 
spectra of hydrogen and other elements in a wide range of excitation 
states.  Hydrogen is the main constituent of such clouds and can get 
optically excited by background star light.  ORFEUS-SPAS data will 
allow determination of the size, distance, density and temperature of 
such clouds, which in turn, aids our understanding of the 
circumstances under which interstellar clouds collapse and new stars 
are born.
 
     Once a star is formed, its evolution is mainly ruled by just one 
parameter, its mass.  High mass stars burn energy, through nuclear 
fusion, more than 100,000 times faster than our sun.  These processes 
give rise to bright ultraviolet emission and strong winds of hot 
ionized material.  ORFEUS will study the surfaces and winds of such 
objects.
    
     Low-mass stars like Earth's sun burn their energy reserves 
relatively slowly, not emitting large amounts of ultraviolet 
radiation.  The outermost layers of their atmospheres can become very 
hot, however, due to turbulent convection which creates shock-waves.  
ORFEUS will measure ultraviolet spectra of such hot layers of 
relatively cold stars in order to contribute to an understanding of 
their physics. 
 
     Most stars end up as compact white dwarfs.  These stars take a 
very long time to cool down.  During this time, they emit most of 
their energy in the ultraviolet wavelength range.  Moreover, they are 
among the brightest EUV sources, which makes them perfect targets for 
ORFEUS-SPAS observations.  ORFEUS data will contribute to a new 
understanding of the cooling mechanisms of white dwarf stars. 

     Once their energy reserves have been depleted, larger stars 
explode as supernovae and return their mass back to the interstellar 
medium. ORFEUS-SPAS is capable of tracing supernova remnants.
 
     Under certain circumstances, the stars of binary systems can 
exchange material, forming hot accretion disks.  ORFEUS observations 
are aimed at determination of mass exchange rates, orbital parameters 
and viscosity.
 
     The physics of accretion disks is of particular interest in 
current astrophysical research, since there is good reason to believe 
that similar phenomena take place on a much larger scale in the 
centers of some galaxies, known as Active Galactic Nuclei (AGN).  
Massive black holes are believed to be surrounded by huge accretion 
disks.  This may even be the case at the center of Earth's galaxy, 
the Milky Way.  Dense dust clouds almost completely prevent direct 
observation of this region.

     AGNs are inherently very bright, but because of the large 
distance from Earth, even the nearest ones appear very faint.  
Therefore, only the brightest AGN may be accessible to ORFEUS 
observations.  Because little information is yet available on these 
exotic objects, even a single spectrum may lead to an important new 
understanding.
 
THE SCIENCE PAYLOAD
 
     The ORFEUS-SPAS science payload is provided by German and U.S. 
research institutions and funded through DARA and NASA. 
 
     The core instrument is the ORFEUS telescope with the FUV Echelle 
spectrometer and the EUV spectrometer, built into the telescope 
structure.  The one meter diameter ultraviolet telescope has a 2.426 
m focal length.  An iridium coating on the primary mirror serves as a 
reflection enhancement for ultraviolet wavelengths.  Essential 
stability against mechanical and thermal load deformations is 
provided by the carbon fibre epoxy compound tube structure. 
 
     The EUV spectrometer is directly exposed to light reflected off 
the main mirror.  It covers the spectral range 40-115 nm, offering a 
resolution of about 5000 over the whole bandwidth.  In order to 
achieve this unprecedentedly high, resolution over such a wide band-
width, a completely new design was used.  A set of four novel 
gratings are the key to producing high quality spectra.  The groove 
density of up to 6,000 lines per millimeter is not uniform, but 
varies over the gratings in a way which compensates for distortions 
introduced by their unusual location in the telescope beam.  Novel 
detectors, allowing for the resolution of single photon events, can 
locate the distance between individual photons with a precision of 
about 30 micro-meter. 

     The FUV Echelle spectrometer is operated alternatively with the 
EUV spectrometer, by flipping a mirror into the beam reflected off 
the primary mirror.  The FUV spectrometer covers the wavelength range 
90-125 nm and provides a spectral resolution on the order of 10,000.  
Two reflection gratings disperse the light into a spectrum, which is 
projected onto a two-dimensional micro channel-plate-detector.  The 
detector is optimized for high spatial resolution. 
 
     IMAPS, the Interstellar Medium Absorption Profile Spectrograph 
is a separate instrument, attached to the ASTRO-SPAS framework.  
IMAPS was successfully flown on several sounding rocket missions.  
IMAPS will be operated for about 1 day during the ORFEUS-SPAS mission 
and during that time will observe the brightest galactic objects.  
IMAPS operates independently of the ORFEUS telescope.  It covers the 
95-115 nm band and provides a resolution of about 240,000, which is 
by far the highest spectral resolution ever achieved by a space 
telescope.  This resolution allows study of fine structure in 
interstellar gas lines.  The individual motions of interstellar gas 
clouds can be determined to an accuracy of 1.6 km per second. 
 
     Another science payload is the Surface Effects Sample Monitor 
(SESAM), a passive carrier for state of the art optical surfaces and 
potential future detector materials.  SESAM will investigate the 
impact of the space environment on materials and surfaces in 
different phases of a Space Shuttle mission, from launch, orbit phase 
to re-entry into the Earth's atmosphere.  Among the SESAM samples are 
also witness samples to the telescope mirror, allowing for accurate 
calibration measurements after landing.  Sample spaces are available 
to scientific and industrial users.  Since SESAM is very efficient 
with respect to volume, weight and resources, it is envisaged for 
future ASTRO-SPAS missions as well.
 
     The Remote IMAX Camera System (RICS) aboard ORFEUS-SPAS will 
take footage of the Shuttle during deployment and retrieval, to 
contribute to a motion picture.  At the same time, RMS operations and 
the ORFEUS-SPAS satellite will be filmed by another IMAX camera 
aboard the shuttle.
 
The ASTRO-SPAS Carrier
 
     ASTRO-SPAS is designed for up to 10 days of autonomous operation 
in the Shuttles vicinity, commanded by the mobile German SPAS Payload 
Operations Center (SPOC).  To keep up with the extended mission 
capability of the Shuttle fleet, increasing the length of the ASTRO-
SPAS operational phase is currently under investigation.

     ASTRO-SPAS provides standardized equipment support panels, 
extensive onboard facilities and resources to scientific payloads.  
Energy is provided by a new powerful Li-SO2 battery pack, which was 
space qualified for ASTRO-SPAS.  Precise attitude-control is achieved 
by a 3-axis stabilized cold gas system in combination with a star 
tracker and a specially developed space borne GPS receiver.  The 
versatility of ASTRO-SPAS permits it to support experiments ranging 
from ultraviolet astronomy to infrared sensing of the Earth's 
atmosphere.  Refurbishment between missions is achieved in less than 
a year. 




   SCIENCE PAYLOAD
 
Instrument           Team Leader                Features
 
Far Ultraviolet      M. Grewing, G. Kraemer     Coverage of the 90-125 
Spectrograph (FUV)   Astronomisches Institut    nm wavelength 
                     Universitaet Tuebingen     range; spectral
                     I. Appenzeller             resolution of 10,000;
                     Landessternwarte           Micro-channel Plate 
                     Heidelberg                 Detector with
                                                optimized spatial 
                                                resolution
 
Extreme Ultraviolet     S. Bowyer, M. Hurwitz    Coverage of the 40-115 
Spectrograph (EUV)      University of California nm wavelength 
                        Berkeley, Calif.         range; spectral 
                                                 resolution of 5,000; 
                                                 detection of individual 
                                                 photons

Interstellar Medium     E. Jenkins               Coverage of 95-115 nm 
Absorption Profile      Princeton University     wavelength range; 
Spectrograph (IMAPS)    Princeton, N.J.          spectral resolution of 
                                                 about 240,000;
                                                 sub-Doppler 
                                                 spectroscopy of 
                                                 interstellar gas lines
 

Surface Effects Sample	D.-R. Schmitt            Carrier for optical 
Monitor (SESAM)	Deutsche Forschungs-     samples to investigate 
                        anstalt fuer Luft- und   degradation of 
                        Raumfahrt (DLR)          surfaces and 
                        Braunschweig             materials in space
                                                 environment; 40 
                                                 places for user
                                                 provided samples




   KEY SPACECRAFT CHARACTERISTICS
 
Total Weight		3,154 kg (1,905 kg available to science
			payload)
 
Dimensions 		4.50 m (payload envelope), 
			2.50 m (front to rear)
 
Design Concept		carbon fibre framework, modular equipment
			support panels support for a 1.2 m telescope
 
Power System		new modular Li-SO2 battery pack with 10 kwh
			each, total of 40 kwh available to payload
 
Attitude Control	3-axis-stabilized cold gas system
 
Thrusters		12 nozzles of 100 mN thrust each
 
Attitude Verification	precision star tracker and Global
			Positioning System (GPS) Receiver
 
Pointing Accuracy	better than 5 arc seconds
 
Telemetry/		S-band link to Shuttle, utilizing NASA standard 

Telecommand		Near Earth Transponder
 
Data Storage		onboard tape recorder, 60 Gbit
 
Mission Control		mobile Micro VAX based SPAS Payload 	
			Operations Center (SPOC) set up at KSC




   Mission Control
 
     ASTRO-SPAS mission control is provided by the SPOC ground 
station at KSC.  The Shuttle is used as a relay station for the 
command and telemetry link.  Real time telemetry data analysis and 
commanding is provided by the micro-VAX-based ground station.  
Science data are stored by an onboard tape recorder.  Downlink of 
quick-look data is available.
 
Future Astro-Spas Missions
 
     The DARA/NASA ASTRO-SPAS program makes provisions for at least 
three more joint missions.  The second mission, named CRISTA-SPAS 
(Cryogenic Infrared Spectrometers and Telescope for the Atmosphere), 
will be launched in 1994.  A better understanding of the photo-
chemistry and small scale dynamics of the Earth's-atmosphere are the 
main objectives of the CRISTA-SPAS mission. 

     A reflight of ORFEUS-SPAS is planned as the third ASTRO-SPAS 
mission.  Increased mission duration and possibly improved instrument 
performance may allow for an extended extra-galactic observation 
program.
 
     CRISTA-SPAS is planned to be reflown as the fourth ASTRO-SPAS 
mission.  In addition, an Automated Rendezvous and Capture (ARC) 
mission, utilizing the ASTRO-SPAS carrier, may be flown later this 
decade as a joint project between the European Space Agency (ESA) and 
NASA.  The ARC mission is designed to demonstrate automated 
rendezvous and capture technologies in support of the space station.




   STS-51 ORFEUS/SPAS RENDEZVOUS OPERATIONS

     The ORFEUS/SPAS will be released by Mission Specialist Dan 
Bursch using Discovery's mechanical arm on the second day of the 
mission.

     While Bursch works with the arm to release the satellite, fellow 
crew member Jim Newman will oversee the mechanical operations of the 
ORFEUS instrument and the SPAS.  The majority of commands to ORFEUS, 
however, will come from ground controllers.

     Once Bursch has released the satellite, Commander Frank 
Culbertson will fire Discovery's small steering jets twice to 
separate from the vicinity of ORFEUS/SPAS, moving at least 13 
nautical miles ahead of the satellite.

     For ORFEUS/SPAS operations, science ground controllers require 
at least 1 1/2 hours of communications with ORFEUS/SPAS out of every 
4 1/2 hours (three orbits).  For these transmissions, Discovery must 
act as a relay station -- ground communications will reach 
ORFEUS/SPAS via Discovery and vice versa.

     ORFEUS/SPAS will fly free of Discovery for almost 6 days.  
Discovery will move from being ahead of the satellite to trailing it 
the day before it is recaptured.  The actual maneuvers to recapture 
the satellite will begin about 5 1/2 hours before ORFEUS/SPAS is 
captured, with Discovery trailing 30 n.m. behind the satellite.  
Discovery then will perform an engine firing to begin closing in on 
to a point 8 n.m. behind the satellite at a rate of about 11 n.m. per 
orbit.  After two orbits and one fine-tuning burn once the 
ORFEUS/SPAS is in sight of the electronic star trackers on the 
Shuttle's nose, Discovery will reach the 8 n.m. point.

     From 8 n.m., the final rendezvous sequence begins with the 
Terminal Intercept (TI) burn.  The TI burn, occurring less than 2 
hours before capture, will send Discovery on a final approach to 
ORFEUS/SPAS.  As Discovery closes in, four mid-course correction 
firings will be done, if needed, with the Shuttle's small steering 
jets.  The dish-shaped Ku-band antenna on the Shuttle will obtain a 
radar lock on the satellite.

     About 1 hour, 10 minutes before capture, when Discovery is 
passing about 1 statute mile below ORFEUS/SPAS, Culbertson will take 
manual control of the rendezvous.  Around that time, two laser 
ranging devices that measure distance and closing rate by bouncing a 
laser beam off of the satellite, will be used for navigation as well.  
One laser ranging unit is hand-held and will be pointed by Pilot Bill 
Readdy through the Shuttle cockpit window at ORFEUS/SPAS.  A second 
laser ranging unit, being flown for the first time, mounted in the 
cargo bay of Discovery, will be remotely operated.  These two units 
will supplement onboard radar information.

     Culbertson will brake Discovery, flying with the control stick 
on the flight deck as it moves toward ORFEUS/SPAS, finally reaching a 
point a few hundred feet in front of the satellite.  While Discovery 
is closing in, Bursch will extend the mechanical arm.  With 
Culbertson moving Discovery to within 35 feet of ORFEUS/SPAS and 
holding position, Bursch will grapple the satellite and reberth it in 
the cargo bay for the trip back to Earth.



   LIMITED DURATION SPACE ENVIRONMENT CANDIDATE MATERIALS EXPOSURE 
(LDCE)

     The primary objective of the Limited Duration Space Environment 
Candidate Material Exposure (LDCE) is to introduce development 
composite materials to a flux atomic oxygen atoms in low-Earth orbit.  
The candidate materials-polymeric, coated polymeric, and light 
metallic composites will have undergone extensive ground based 
material performance testing prior to being attached to reusable test 
fixtures designed for multi-mission Space Shuttle use.

     The LDCE, configuration C, consists of two standard 5-cubic-foot 
GAS cans with Motorized Door Assemblies (MDA's).  A crewmember uses 
the Autonomous Payload Control System to control the payload from the 
aft flight deck.  The LDCE is a simple exposure experiment that 
utilizes an MDA on each can but does not contain any batteries or 
fluids.


CHROMOSOMES AND PLANT CELL DIVISION IN SPACE  
(CHROMEX-4)

Principal investigators:  
Dr. Abraham Krikorian, State University of New York at Stony Brook
Dr. Mary Musgrave, Louisiana State University
Dr. Norman Lewis, Washington State University

     The upcoming flight of the CHROMEX-4 experiment is the fourth in 
a series of Life Sciences middeck experiments dealing with the growth 
of plants in microgravity.

     The CHROMEX-4 payload consists of three scientific experiments.  
They are plant reproduction studies which are a reflight of the 
CHROMEX-3 experiment;  plant cell developmental studies which carry 
the studies of CHROMEX-1 and CHROMEX-2 to another plant species;  and 
cell wall formation and gene expression studies.  The CHROMEX-4 
payload also will provide the opportunity to evaluate a new nutrient 
support system developed at Washington State University.

     The anticipated science benefits may lead to new strategies to 
manipulate and exploit the effect of gravity in plant growth, 
development, biochemistry and biotechnology.  Such understandings 
will directly benefit the agriculture, horticulture and forestry 
industries which depend upon plant growth for their products.

     The plants being studied on CHROMEX-4 are mouse-ear cress 
(Arabidopsis thaliana) and a strain of wheat (Triticum aestivum).

     Arabidopsis is a small, fast-growing plant widely studied by 
plant scientists.  It is found in the wild and cultivated for 
research.  This plant will self pollinate during the 9-day mission 
and begin producing seeds.  Dr. Musgrave will investigate the effects 
of the microgravity environment on seed production and seed forming 
structures of the plants.

     Triticum is a superdwarf variety of wheat and has been widely 
studied among plant researchers.  Root and shoot development, cell 
wall formation and gene expression studies are being conducted on 
these specimens by Drs. Krikorian and Lewis.

     These plant specimens and their nutrient support systems are 
integrated with the Plant Growth Chambers (PGC) approximately 1 day 
before launch.  The PCGs are loaded into the Plant Growth Unit (PGU).  
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 payload crew is required to perform nominal experiment activities 
consisting of a daily status check to monitor the PGU's systems' 
function.

     Following the flight of these plants, the investigators will 
perform complete dissections of the entire plant structure and 
preserve the tissues by chemical fixation or flash freezing.

     The PGU was developed by NASA.  The experiment is sponsored by 
NASA's Office of Life and Microgravity Sciences and Applications.




   STS-51 EXTRAVEHICULAR ACTIVITY

     STS-51 crewmembers Carl Walz and Jim Newman will perform a 6-
hour extravehicular activity (EVA), or spacewalk, on the fifth day of 
the mission as a continuation of a series of test spacewalks NASA is 
conducting to increase experience with spacewalks and refine 
spacewalk training methods.

     Walz will be designated extravehicular crew member 1 (EV1) and 
Newman will be EV2.  Pilot Bill Readdy will serve as the 
intravehicular (IV) crew member inside Discovery, supervising the 
coordination of spacewalk activities in the Shuttle's cargo bay.

     In addition to performing tasks that investigate a spacewalker's 
mobility in general, Walz and Newman will evaluate several tools that 
may be used during the servicing of the Hubble Space Telescope (HST) 
later this year on mission STS-61, including a power socket wrench, a 
torque wrench, foot restraint, safety tethers and tool holder. 

     Unlike Shuttle mission STS-57, the astronauts will not use the 
50-foot long robot arm during the spacewalk, since it will be 
important for use several days after the spacewalk to retrieve the 
ORFEUS-SPAS satellite.  Walz and Newman will spend part of their time 
outside Discovery testing various types of rigid and semi-rigid 
tethers as well as moving up and down the bay carrying each other, 
evaluating how well spacewalking astronauts can maneuver in 
weightlessness with a large object.

     Other tests include an evaluation of how well an astronaut must 
be restrained in weightlessness to apply a large amount of tightening 
to a bolt using the tools provided. In addition, the spacewalkers 
will use a large tool onboard Discovery for use in case of a problem 
with the ACTS/TOS satellite's deployment to evaluate methods of using 
bulky tools.

     As is the rule with the test spacewalks, the STS-51 EVA will be 
one of the lowest priorities of the flight, subject to cancellation 
if needed due to a problem with one of the primary payloads.  It is 
planned with a minimum of extra equipment flown on Discovery, making 
optimum use of materials already aboard for other purposes.

     The planned spacewalk will be the third such test spacewalk this 
year.  Previous spacewalk tests were conducted on STS-54 in January 
and STS-57 in June.  NASA plans to continue adding spacewalks to 
Shuttle flights when they can be performed without interference to 
the primary activities onboard.  The STS-51 spacewalk is the final 
test EVA planned for 1993.  The spacewalks planned for STS-61 in 
December will be performed to service the HST and not for test 
purposes.




STS-51 RADIATION MONITORING EQUIPMENT-III  (RME-III)

     The Radiation Monitoring Equipment-III (RME-III) measures 
ionizing radiation exposure to the crew within the orbiter cabin.  
RME-III measures gamma ray, electron, neutron and proton radiation 
and calculates in real time exposure in RADS-tissue equivalent.  The 
information is stored in a memory module for post-flight analysis.

     The hand-held instrument is stored in a middeck locker during 
flight except for when the crew activates it and replaces the memory 
module every two days.  RME-III will be activated by the crew as soon 
as possible after they achieve orbit and it will operate throughout 
the mission.  A crew member will enter the correct mission elapsed 
time upon activation.  ME-III is sponsored by the Department of 
Defense in cooperation with NASA.


AIR FORCE OPTICAL SITE  (AMOS)

     This geophysical environmental study will test ground based 
optical sensors.  The experiment will also examine 
contamination/exhaust plume phenomena using the Space Shuttle as a 
calibration target.


AURORA PHOTOGRAPHY EXPERIMENT-B  (APE-B)

     The mission objectives of the Aurora Photography Experiment-B 
(APE-B) are to photograph the airglow aurora, auroral optical 
effects, the Shuttle glow phenomenon and thruster emissions in the 
imaging mode of photography as well as in the Fabry-Perot and 
spectrometer modes of photography. 


COMMERCIAL PROTEIN CRYSTAL GROWTH (CPCG)

     The Commercial Protein Crystal Growth (CPCG) payload is designed 
to conduct experiments which supply information on the scientific 
methods and commercial potential for growing large high-quality 
protein crystals in microgravity.  The CPCG payload consists of 
Commercial Refrigerator/Incubator Modules (CR/IM's) and their 
contents.

     There are two possible configurations for this experiment, Block 
I and Block II.  This experiment is configured in Block II 
configuration for the STS-51 mission, in which the CR/IM contents 
consist of four cylinder containers of the same diameter but 
different volumes.  The four cylinders are 500 mm, 200 mm, 100 mm and 
20 mm.  Depending on the specific protein being flown, the 
temperature is either lowered or raised in up to a five-step process 
over Flight Day 1 and 2.

     One CR/IM occupies the space of one middeck stowage locker.  
Orbiter 28V dc power is provided to the CPCG CR/IM via single power 
cables from a standard middeck outlet.  The CPCG experiment is 
installed at the pad within launch minus 24 hours.



HIGH RESOLUTION SHUTTLE GLOW SPECTROSCOPY
(HRSGS-A)

     The High Resolution Shuttle Glow Spectroscopy-A (HRSGS-A) is an 
experimental payload designed to obtain high resolution spectra in 
the visible and near visible wavelength range (4000 angstroms to 8000 
angstroms) of the Shuttle surface glow as observed on the orbiter 
surfaces which face the velocity vector while in low Earth-orbit.  
The spectral resolution of the spectrograph is 2 angstroms and it is 
hoped this will help identify the cause of the Shuttle glow.  The 
HRSGS-A will look at the vertical tail, Orbital Maneuvering System 
Pod or a suitable alternative. 


IMAX

     The IMAX payload is a 70mm motion picture camera system for 
filming general orbiter scenes.  The system consists of a camera, 
lenses, rolls of film, two magazines with film, an emergency speed 
control, a Sony recorder and associated equipment, two photographic 
lights, supporting hardware in the form of mounting brackets to 
accommodate the mode of use, two cables and various supplemental 
equipment.

     The IMAX and supporting equipment are stowed in the middeck for 
in-cabin use.  The IMAX uses two film magazines which can be 
interchanged as part of the operation.  Each magazine runs for 
approximately 3 minutes.  When both magazines are consumed, reloading 
of the magazines from the stowed supply of film is required.  Lenses 
are interchanged based on scene requirements.  The IMAX will be 
installed in the orbiter middeck approximately 7 days prior to 
launch.


INVESTIGATION INTO POLYMER MEMBRANES PROCESSING (IPMP)

     The research objectives of the IPMP is to flash evaporate mixed 
solvent systems in the absence of convection to control the porosity 
of a polymer membrane.  Two experimental units will be flown.  Each 
unit will consist of two 304L stainless steel sample cylinders 
connected to each other by a stainless steel packless valve with an 
aluminum cap.  Before launch, the two larger canisters are evacuated 
and sealed with threaded stainless steel plugs using a Teflon(  tape 
threading compound.

     In the smaller units, a thin film polymer membrane is swollen in 
a solvent compound.  The film is rolled up and inserted into the 
canisters.  The small canisters are sealed at ambient pressure 
(approximately 14.7 psia).  The valves are secured with Teflon(  
tape.

     The locker containing the IPMP payload will be installed in the 
orbiter during the period from L-6 to L-3 days.




STS-51 CREW  BIOGRAPHIES

     Frank L. Culbertson, Jr., 44, Capt., USN, will command STS-51.  
Selected as an astronaut in 1984, Culbertson will be making his 
second space flight and considers Holly Hill, S.C., his hometown.

     Culbertson graduated from Holly Hill High School in 1967 and 
received a bachelor of science in aerospace engineering from the 
Naval Academy in 1971.

     After serving aboard the USS Fox in the Vietnam War, Culbertson 
was designated a Naval aviator in 1973 and, from 1974-1976, he served 
as an F-4 Phantom pilot aboard the USS Midway.  Subsequently, he was 
assigned as an exchange pilot with the Air Force, serving as a 
weapons and tactics instructor at Luke Air Force Base, Ariz., until 
1978.  His next assignment was as the catapult and arresting gear 
officer aboard the USS John F. Kennedy.  In 1982, he graduated with 
distinction from the Naval Test Pilot School and, subsequently, 
served as a test pilot in the Carrier Systems Branch.  He was engaged 
in fleet replacement training in the F-14A Tomcat in 1984 until his 
selection by NASA.

     Culbertson's first shuttle flight was as pilot of STS-38, a 
Department of Defense-dedicated mission in November 1990.  He has 
logged more than 117 hours in space, more than 4,500 hours flying 
time in 40 different types of aircraft and 450 carrier landings.

     William F. Readdy, 41, will serve as pilot. Selected as an 
astronaut in 1987, Readdy will be making his second space flight and 
considers McLean, Va., his hometown.

     Readdy graduated from McLean High School in 1970 and received a 
bachelor of science in aeronautical engineering from the U. S. Naval 
Academy in 1974.

     Readdy was designated a Naval aviator in 1975. From 1976-1980, 
he served as an A-6 pilot aboard the USS Forrestal. He graduated from 
the Naval Test Pilot School in 1981.  His Navy assignments included 
the Strike Aircraft Test Directorate, instructor duty at the Naval 
Test Pilot School and strike operations officer aboard the USS Coral 
Sea.

     In 1986, Readdy accepted a reserve commission from the Navy to 
join NASA as a research pilot and aerospace engineer at JSC.  Prior 
to his selection as an astronaut, he served as program manager for 
the Shuttle Carrier Aircraft. 

     Readdy's first flight was on STS-42, the first flight of the 
International Microgravity Lab (IML), in January 1992.  Readdy has 
logged more than 193 hours in space and more than 5,500 hours flying 
time in 50 types of aircraft, including more than 550 carrier 
landings.

     James H. Newman, 36, will be Mission Specialist 1 (MS1).  
Selected as an astronaut in 1990, Newman will be making his first 
space flight and considers San Diego, Calif., his hometown.

     Newman graduated from La Jolla High School, San Diego, in 1974; 
received a bachelor of arts in physics from Dartmouth College in 
1978; and received a master's and doctorate in physics from Rice 
University in 1982 and 1984, respectively.

     Newman performed post-doctoral work at Rice in atomic and 
molecular physics and was appointed an adjunct assistant professor in 
the Department of Space Physics in 1985.  He later joined NASA, 
serving as a simulation supervisor for astronaut training at the time 
of his selection 

     Daniel W. Bursch,  Commander, USN, will be Mission Specialist 2 
(MS2).  Selected as an astronaut in January 1990, Bursch will be 
making his first space flight and considers Vestal, N.Y., his 
hometown.

     Bursch graduated from Vestal Senior High School in 1975; 
received a bachelor of science in physics from the Naval Academy in 
1979; and received a master's in engineering science from the Naval 
Postgraduate School in 1991.

     Bursch was designated a Naval flight officer in 1979 and was 
assigned to Attack Squadron 34 as a bombardier/navigator in the A-6E 
Intruder.  He graduated from the Naval Test Pilot School in 1984 and 
later returned to the school as a flight instructor.  Later, he was 
assigned as strike operations officer for Commander, Cruiser 
Destroyer Group One.  He had just completed work at the Naval 
Postgraduate School at the time of his selection by NASA.

     He has logged more than 1,800 flying hours in 35 types of 
aircraft. 

     Carl E. Walz, 37, Major, USAF, will be Mission Specialist 3 
(MS3). Selected as an astronaut in January 1990, Walz will be making 
his first space flight and was born in Cleveland.

     Walz graduated from Charles F. Bush High School, Lyndhurst, 
Ohio., in 1973; received a bachelor of science in physics from Kent 
State University in 1977; and received a master's in solid state 
physics from John Carroll University in 1979.

     Commissioned in the Air Force, from 1979-1982, Walz was assigned 
as radiochemical project officer with the 1155th Technical Operations 
Squadron at McClellan Air Force Base, Calif.  He graduated as a 
flight test engineer from the Air Force Test Pilot School in 1983.  
From 1983-1987, Walz was assigned to the F-16 Combined Test Force, 
and in 1987 he was assigned as a flight test program manager at Det. 
3, Air Force Flight Test Center, where he served at the time of his 
selection by NASA.




STS-51 MISSION MANAGEMENT

NASA HEADQUARTERS, WASHINGTON, D.C.

Office of Space Flight

Jeremiah W. Pearson III - Associate Administrator
Bryan O'Connor - Deputy Associate Administrator
Tom Utsman - Space Shuttle Program Director
Brewster Shaw - Director, Space Shuttle Operations (JSC)
Loren Shriver - Technical Assistant to the Director of Space Shuttle 
Operations (KSC)


Office of Advanced Concepts and Technology

Gregory M. Reck - Acting Associate Administrator
Jack Levine - Acting Director, Flight Projects Division
Andrew B. Dougherty - Spacehab Utilization Program Manager
Richard H. Ott - ActingDirector, Space Processing Division
Ana M. Villamil - Acting Deputy Director, Space Processing Division
Dan Bland - Commercial Middeck Augmentation Module Project Manager 
(JSC)

Office of Safety and Mission Assurance

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

Office of Life and Microgravity Sciences and Applications
Gary Martin - SAMS Program Manager


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
David King - Discovery 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
Joann H. Morgan - Director, Payload Ground Operations
Mike Kinnan - STS-51 Payload Manager




   MARSHALL SPACE FLIGHT CENTER, HUNTSVILLE, ALA.

Thomas J. Lee - Director
Dr. J. Wayne Littles - Deputy Director
Alexander A. McCool - Manager, Shuttle Projects Office
Harry G. Craft, Jr. - Manager, Payload Projects Office
Sid Saucier - Manager, Space Systems Projects Office
Alvin E. Hughes - Manager, Upper Stage Projects
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 AFB, CALIF.

Kenneth J. Szalai - Director
Robert R. Meyers, Jr. - Assistant 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 - Director
Thomas E. Huber - Director, Engineering Directorate
Robert Weaver - Chief, Special Payloads Division
David Shrewsberry - Associate Chief, Special Payloads Division


GERMAN SPACE AGENCY (DARA), BONN, GERMANY

Heinz Stoewer - Managing Director Space Utilization
Gernot Hartmann - Head of Space Science Division
Roland Wattenbach - ASTRO-SPAS Program/Project Manager,
Klaus Steinberg - ORFEUS-SPAS Project Manager
Rolf Densing - ASTRO-SPAS System Scientist
Wolfgang Frings - ASTRO-SPAS representative at NASA-JSC
Franz-Peter Spaunhorst - Head of Public Affairs Office
Rudolf Teuwsen - ASTRO-SPAS Public Affairs Manager
