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                       
202/358-1778
  Headquarters, Wash., D.C.

James Hartsfield          Mission Operations/EVA                  
713/483-5111
  Johnson Space Center,   Astronauts
  Houston

Bruce Buckingham          Launch Processing                       
407/867-2468
  Kennedy Space Center, Fla.                                      
KSC Landing Information

June Malone               External Tank/SRBs/SSMEs                
205/544-0034
  Marshall Space Flight
  Center, Huntsville, Ala.

Nancy Lovato              DFRF Landing Information                
805/258-3448
  Dryden Flight Research 
  Facility, Edwards, Calif.


       For Information on NASA-Sponsored STS-51 Experiments

Michael Braukus           ORFEUS-SPAS                             
202/358-0872
  Headquarters, Wash., D.C.                                       
ACTS hardware

Charles Redmond           ACTS experiments                        
202/358-1757
  Headquarters, Wash., D.C.                                       














                                i
                             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

                                ii





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. 


                             - more -



     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                      Flight Day Seven
Ascent                              Stationkeeping burns
OMS-2 (160 n.m. x 161 n.m.)         (158 n.m. x 159 n.m.)
Remote Manipulator System checkout  LDCE operations
CHROMEX check                       APE operations
CPCG activation                     HRSGS operations
RME activation                      HRSGS stow
ACTS/TOS deploy                     CHROMEX check
RCS, OMS Separation burns           RME check
(161 n.m. x 173 n.m.)

Flight Day Two                      Flight Day Eight
OMS, RCS burns (158 n.m. x 159 n.m.) ORFEUS/SPAS rendezvous
ORFEUS/SPAS checkout                ORFEUS/SPAS berth
ORFEUS/SPAS release                 CHROMEX check
RCS Separation burns (158 n.m. x 159 n.m.) DTO 412: Fuel Cell 
shutdown
CHROMEX check                       
Cabin depress to 10.2 psi           
                                    

Flight Day Three                    Flight Day Nine
Stationkeeping burns (158 n.m. x 159 n.m.) Cabin repress to 14.7 
psi
IPMP activation                     Flight Control Systems 
checkout
CHROMEX check                       Reaction Control System 
hot-fire
                                    AMOS
Flight Day Four                     CHROMEX check
EMU checkout                        Cabin stow
Stationkeeping burns (158 n.m. x 159 n.m.) DTO 412: Fuel Cell 
restart
RME check                           
                                    
Flight Day Five                     Flight Day Ten
Extravehicular activity preparations Deorbit preparations
Extravehicular activity (six hours) Deorbit burn
Stationkeeping burns (158 n.m. x 159 n.m.) Entry
CHROMEX check                       Landing

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






               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
                                      
                                      
                                      
                                      
                  STS-51 CARGO CONFIG (GRAPHIC)
                                      
          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.




              ACTSON-ORBIT COPNFIGYRATION (GRAPHIC)

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.


              ACTS MISSION EVENTS SEQUENCE (GRAPHIC)
                                      

  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
   operations 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.

         TYPICAL ACTS SYSTEM OPERATING SCENARIOS (GRAPHIC)
                                      

     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 
                   TOS CONFIGURATION (GRAPHIC)
                                      

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 

                        ORPHEUS (GRAPHIC)

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.

     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