Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/STSKITS/STS_50.KIT

Text File | 1992-06-23 | 110KB | 2,474 lines

STS-50 PRESS KIT






                             STS-50 PRESS KIT

                           SPACE SHUTTLE COLUMBIA

                              USML-1 MISSION

                               JUNE, 1992





                                      i


                                  CONTENTS

General Release                                           1
STS-49 Quick Look Facts                                   2
STS-50 Vehicle And Payload Weights                        3
STS-50 Trajectory Sequence Of Events                      4
Space Shuttle Abort Modes                                 5
The U.S.  Microgravity Laboratory-1 Mission               6
Materials Science                                        10
Crystal Growth Furnace Experiments                       10
Zeolite Crystal Growth                                   15
Fluid Physics  Experiments                               18
Astroculture (TM)                                        22
Surface Tension Driven Convection Experiment (Stdce)     26
Combustion Science Experiment                            27
    Solid Surface Combustion Experiment (SSCE)           27
Protein Crystal Growth (PCG)                             28
Biotechnology Experiments                                31
    Generic Bioprocessing Apparatus                      31
Glovebox (GBX)                                           33
Space Acceleration Measurement Systems (Sams)            42
Extended Duration Orbiter Medical Project (Edomp)        42
Investigations Into Polymer Membrane Processing (IPMP)   45
Orbital Acceleration Research Experiment (OARE)          46
Shuttle Amateur Radio Experiment                         46
Sts-50 Prelaunch Processing                              48
STS-50 Crew Biographies                                  49
Sts-50 Mission Management                                41




48th SHUTTLE MISSION TO BE LONGEST, FOCUS ON WEIGHTLESSNESS


Release:  92-81

     The longest flight ever for a Space Shuttle and around-
the-clock investigations of the effects of weightlessness on
plants, humans and materials will highlight Shuttle mission
STS-50.

     The 48th flight of a Space Shuttle and the 12th flight of
Columbia, STS-50, carrying the U.S. Microgravity Laboratory-1
(USML-1), is planned for launching at 12:05 p.m. EDT on late
June.  The mission is scheduled to last 12 days, 20 hours and
28 minutes, with landing planned at Edwards Air Force Base,
Calif.

     Richard N. Richards, 45, Capt., USN, will command STS-50,
his third space flight.  The pilot will be Kenneth D. Bowersox,
36, Lt. Cmdr., USN, making his first space flight.  Mission
specialists include Bonnie Dunbar, 43, who also will be Payload
Commander and making her third flight; Ellen Baker, 39, making
her second flight; and Carl Meade, 41, Col., USAF, making his
second flight.  Payload specialists include Lawrence J.
DeLucas, 41, from the Center for Macromolecular Crystallography
at the University of Alabama, making his first flight, and
Eugene H. Trinh, 41, a research physicist on the Space Station
Freedom experiments planning group, making his first flight.

     USML-1 includes 31 experiments ranging from manufacturing
crystals for possible semiconductor use to the behavior of
weightless fluids.  In addition, STS-50 will carry the
Investigations into Polymer Membrane Processing experiment, an
experiment in manufacturing polymers, used as filters in many
terrestrial industries, and the Space Shuttle Amateur Radio
Experiment-II, an experiment that allows crew members to
contact ham radio operators worldwide and conduct question-and-
answer sessions with various schools.

     Columbia is currently the only Shuttle capable of a 13-day
flight and will carry the necessary additional hydrogen and
oxygen supplies on a pallet in the cargo bay. New systems for
removing carbon dioxide from the crew cabin, for containing
waste and for increased stowage of food and crew equipment also
have been added.

     The crew will perform several ongoing medical
investigations during the flight as well, research that aims at
counteracting the effects of prolonged exposure to
weightlessness on the human physique.

                   - end of general release -

STS-49 QUICK LOOK FACTS


Orbiter:                Columbia (OV-102)

Launch Date and Time:   Late June 1992

Launch Window:          3 hours, 8 min. (12:05 - 3:13 p.m. EDT)

Launch Site:            Kennedy Space Center, Fla., Pad 39-A

Altitude/Inclination:   160 n.m. x 160 n.m./28.5 degrees

Mission Duration:       12/20:28:00 MET

Primary Landing Site:   Edwards Air Force Base, Calif.

Abort Landing Sites:    Return to Launch Site - Kennedy Space
                        Center, Fla.
                        Transoceanic Abort Landing -
                        Banjul, The Gambia
                        Alternates - Ben Guerir, Morocco;
                        Rota, Spain
                        Abort Once Around - Edwards Air Force
                        Base, Calif.

Crew:                   Dick Richards, Commander
                        Ken Bowersox, Pilot
                        Bonnie Dunbar, Mission Specialist 1,
                        Payload Commander
                        Ellen Baker, Mission Specialist 2
                        Carl Meade, Mission Specialist 3
                        Larry DeLucas, Payload Specialist 1
                        Gene Trinh, Payload Specialist 2

Cargo Bay Payloads:     U.S. Microgravity Laboratory-1 (USML-1)
                        Crystal Growth Furnace (4 experiments)
                        Drop Physics Module (3 experiments)
                        Surface Tension Driven Convection
                        Experiment
                        Solid Surface Combustion Experiment
                        Glovebox (16 experiments)
                        Space Acceleration Measurement
                        System(SAMS)

Middeck Payloads:       Astroculture-1 (ASC-1)
                        Generic Bioprocessing Apparatus (GBA)
                        Commercial Protein Crystal Growth
                        (CPCG)
                        Zeolite Crystal Growth (ZCG)

Secondary Payloads:     Extended Duration Orbiter Medical
                        Project (EDOMP)
                        Investigations into Polymer Membrane
                        Processing (IPMP)
                        Orbital Acceleration Research
                        Experiment (OARE)
                        Shuttle Amateur Radio Experiment-II
                        (SAREX-II)
                        Ultraviolet Plume Instrument (UVPI)

STS-50 Vehicle and Payload Weights


                                                         Pounds

Orbiter (Columbia) empty, and 3 Space Shuttle
  Main Engines                                          181,344

U. S. Microgravity Laboratory                            22,199

Protein Crystal Growth                                      229

Investigation of Polymer Membrane Processing                 36

Shuttle Amateur Radio Experiment                             52

Zeolite Crystal Growth                                      126

Generic Bioprocessing Apparatus                              69

Detailed Supplementary Objectives                           248

Detailed Test Objectives                                    122

Extended Duration Orbiter Pallet                          3,597

Total Vehicle at Solid Rocket Booster Ignition        4,523,834

Orbiter Landing Weight                                  228,866



STS-50 TRAJECTORY SEQUENCE OF EVENTS

                                   RELATIVE
                       MET         VELOCITY   ALTITUDE
EVENT                (d:h:m:s)       (fps)      MACH     (ft)


Launch              00/00:00:00

Begin Roll Maneuver 00/00:00:10         189      .17      800

End Roll Maneuver   00/00:00:14         301      .27    1,968

SSME Throttle
Down to 67%         00/00:00:35        842      .77    12,795

Maximum Dyn.
Pressure (Max Q)    00/00:00:51      1,178     1.13    27,314

SSME Throttle Up
to 104%             00/00:01:02      1,464     1.49    39,895

SRB Separation      00/00:02:04      4,167     3.95    55,799

Main Engine
Cutoff (MECO)       00/00:08:31     24,572    22.73    63,636

Zero Thrust         00/00:08:37     24,509     N/A     62,770

External Tank
Separation          00/00:08:50

Orbital Maneuvering
System-2 Burn       00/00:34:55

Landing             12/20:28:00


Apogee, Perigee at MECO:     156 x 35 nautical miles

Apogee, Perigee post-OMS 2:  162 x 160 nautical miles


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 the Earth before
landing at either Edwards Air Force Base, Calif., White Sands
Space Harbor, N.M., or the Shuttle Landing Facility (SLF) at
the Kennedy Space Center, Fla.

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

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

      STS-50 contingency landing sites are Edwards Air Force
Base, the Kennedy Space Center, White Sands Space Harbor,
Banjul, Ben Guerir and Rota.

THE U.S. Microgravity Laboratory-1 MISSION


      The U. S. Microgravity Laboratory (USML) -1 and
subsequent missions will bring together representatives from
academia, industry and the government to study basic scientific
questions and gain new knowledge in materials science,
biotechnology, combustion science, the physics of fluids and
the way energy and mass are transported within them.  The U.S.
Microgravity Laboratory series will help the United States
maintain world leadership in microgravity research and
development.

      As Space Station Freedom development proceeds, the USML
missions will continue development and testing of experimental
flight equipment and will be laying the scientific foundation
for microgravity research conducted over extended time periods.
In addition, USML experiments will be conducted on nutrient and
water transport for growing food in space, on the behavior of
fire in low-gravity and on the effects of long-term space
travel on humans.

      In June 1992, the USML-1 Spacelab mission -- designated
STS-50 -- will be launched into a 160-nautical-mile orbit
aboard the Space Shuttle Columbia.  It will be a 13-day mission
to perform scientific investigations using some of the latest
high-technology research equipment.  Because of the great
number of experiments planned for the mission and to fully
utilize the time in microgravity, the crew will be split into
two teams.  Each team will work a 12-hour shift to maintain
around-the-clock operations.


The Laboratory

      Spacelab is a modular research laboratory flown within
the Shuttle orbiter's cargo bay.  It includes interchangeable
elements, including open U-shaped platforms, called pallets
(for equipment such as telescopes that require direct exposure
to space), and short and long laboratory modules.  The
laboratory modules are pressurized so researchers can work in a
laboratory environment in their shirt sleeves rather than bulky
spacesuits.  These elements are arranged in the Shuttle cargo
bay to meet the unique needs of each mission.

      For USML-1, the long pressurized module will be used.
This 23-foot-long laboratory workshop will contain a series of
standard racks that will hold furnaces for growing crystals,
facilities for studying the behavior of fluids and doing
combustion research, computers and other equipment needed for
the various experiments.

      During USML-1, as with all NASA Spacelab missions, flight
controllers and experiment scientists direct science activities
from the Spacelab Mission Operations Control Center in
Huntsville, Ala.  They have a direct voice communication link
with the orbiting Spacelab crew, and on-board video cameras
make it possible for them to view crew and experiment
activities.  Scientists and controllers on the ground can
receive information from Spacelab experiments and send commands
via computer links.  With this communications access,
scientists on the ground and in orbit can work together,
sharing information about experiments, monitoring data, solving
problems and revising experiment plans.


Extended Mission

      Shuttle missions usually have been less than 10 days.  At
13 days, USML-1 will be the longest Shuttle mission to date.
This will be made possible by the first use of the new Extended
Duration Orbiter kit, which includes equipment and fuel for
extra energy production, additional nitrogen tanks for cabin
air and a regeneration system to remove carbon dioxide.  The
kit eventually may permit Shuttle missions up to 30 days long.


What Is Microgravity?

      Microgravity literally means a state of very small or
minute gravity.  Earth's gravitational field extends far into
space.  It is the Shuttle's balance between that gravity, which
pulls it down, and centrifugal force, created as the Shuttle
flies along a circular path, that causes space travelers and
anything in the Shuttle that is not  secured to "float" in
space as they fall free in Earth's gravitational field.  Though
microgravity is a relatively new term, it could become a
household word in the next century as the potential benefits of
space-based research are realized.


USML-1 Experiments

      Equipment used and data obtained during earlier Shuttle
missions provide a basis on which many of the USML-1
investigations will build.  During the USML-1 mission, 31
experiments will be conducted in four broad areas -- materials
science, fluid physics, combustion science and biotechnology --
in addition to the study of accelerations in the Shuttle and
the complementary glovebox experiments.

      Laboratory hardware includes new equipment, such as the
Crystal Growth Furnace, and some equipment that has flown
previously, such as the Solid Surface Combustion Experiment.








MATERIALS SCIENCE

      While in space, materials can be formed in ways not
possible on Earth.  Research performed in the microgravity
environment of Spacelab has greatly reduced gravitational
effects, such as settling and separation of components and
convection.

      The Crystal Growth Furnace is new equipment developed
specifically to study directional solidification of materials
(primarily semi-conductors), which form the basis of electronic
devices.  Over the past few decades, semiconductor technology
has revolutionized our lifestyle through consumer goods such as
smaller, faster computers, more precise timepieces and a wide
variety of audio/video and other communication equipment that
just a few years ago were found only in science fiction.

      The Crystal Growth Furnace is one of the first U.S.
furnaces developed for spaceflight that processes samples at
temperatures above 2,300 degrees Fahrenheit (approximately
1,300 degrees Centigrade).  This reusable equipment will help
scientists investigate the different factors affecting crystal
growth and explore the best methods to produce better crystals.

      Four experiments to be conducted in the Crystal Growth
Furnace will result in crystals grown from different materials:
cadmium telluride, mercury zinc telluride, gallium arsenide and
mercury cadmium telluride.  These crystals are used in infrared
detectors found in certain medical equipment, night-vision
goggles and sensors used in some telescopes.

      In the orbiter crew cabin mid-deck area, zeolite crystals
will be grown.  Zeolite crystals act as sponges or filters.
They are called molecular sieves because they strain out
specific molecules from a compound.  High-quality zeolites may
one day allow gasoline, oil and other petroleum products to be
refined less expensively.

      Protein crystal growth experiments -- also conducted in
the mid-deck -- will study the growth of crystals in a low-
gravity environment.  Proteins are large, complex compounds
made of a very specific arrangement of amino acids present in
all life forms.  Like the minerals named above, proteins also
can have a crystalline structure.

      The function of a certain type of protein is determined
by its molecular arrangement.  By understanding how a protein
is structured, scientists may be better able to develop foods
that have improved nutritional value.  Also, medicines that act
in a specific way with fewer side effects or new medicines to
treat diseases may be designed.


STS-50 Mission Experiments

Crystal Growth Furnace Experiments

      On USML-1, four principal investigators (PIs) will use
the Crystal Growth Furnace (CGF) to study the effect of gravity
on the growth of a variety of materials having electronic and
electro-optical properties.  Gravity contributes to the
formation of defects during the production of crystals of these
materials through convection, sedimentation and buoyancy
effects.  These gravity-induced complications result in
problems ranging from structural imperfections to chemical
inhomogeneity.  By conducting crystal growth research in
microgravity, scientists can investigate the different factors
affecting crystal growth and determine the best methods to
produce various types of crystals.





      The CGF is the first space furnace capable of processing
multiple large samples at temperatures up to 1800!F (1350!C).
The CGF consists of three major subsystems:  the Integrated
Furnace Experiment Assembly (IFEA), the Avionics Subsystem and
the Environmental Control System (ECS).  The IFEA houses a
Reconfigurable Furnace Module (RFM) -- a modified Bridgman-
Stockbarger furnace with five controlled heating zones -- a
Sample Exchange Mechanism capable of holding and positioning up
to six samples for processing and a Furnace Translation System
which moves the furnace over each sample.  Sample material is
contained in quartz ampoules mounted in containment cartridges.
Thermocouples mounted in each cartridge provide temperature
data.  The Avionics Subsystem monitors and controls the CGF
experiments and provides the interface with the Spacelab data
system.  The ECS maintains and controls the argon processing
atmosphere inside the IFEA and provides cooling to the outer
shell of the furnace through connections to Spacelab Mission
Peculiar Equipment (MPE) fluid loop.

      Once on orbit, a crew member will open the IFEA and load
six experiment samples into the Sample Exchange Mechanism.  The
samples are processed under computer control.  PIs can change
experiment parameters via command uplinking.  A flexible
glovebox is used to provide crew access to the interior of the
IFEA should an ampoule/cartridge fail on orbit.


Orbital Processing of High-Quality CdTe Compound Semiconductors

Principal Investigator:

Dr. David J. Larson, Jr.
Grumman Corporation Research Center

      Cadmium Zinc Telluride (CdZnTe) crystals are used as
lattice-matched substrates in a variety of mercury cadmium
telluride (HgCdTe) infrared detectors.  Reducing defects in the
CdZnTe substrate minimizes the propagation of defects into the
active HgCdTe layer during its growth. The purpose of the
experiment is to quantitatively evaluate the influences of
gravitationally-dependent phenomena (convection and hydrostatic
pressure) on the chemical homogeneity and defect density of
CdZnTe.

      Processing the CdZnTe crystals in microgravity could
significantly improve the chemical homogeneity of the
substrates, minimizing interface strain and reducing the
defects that result from gravitationally dependent phenomena.
This improvement in substrate quality should enhance the
quality and performance of the HgCdTe active detector.  An
improved understanding of gravitationally-dependent
thermosolutal convection on the structural and chemical quality
of alloyed compound semiconductors may help improve modeling of
the semiconductor growth process which, in turn, would result
in improving the chemical homogeneity and defect densities of
the material, as well as increasing the primary yield of high
quality material for infrared applications.

      The sample on USML-1 (Cd0.96Zn0.04Te) will be processed
using the seeded Bridgman-Stockbarger method of crystal growth.
Bridgman-Stockbarger crystal growth is accomplished by
establishing isothermal hot-zone and cold-zone temperatures
with a uniform temperature gradient between.  The thermal
gradient spans the melting point of the material (1,095!C).
After sample insertion, the furnace's hot and cold zones are
ramped to temperature (1,175!C and 980!C respectively)
establishing a thermal gradient of 25!C/cm and melting the bulk
of the sample.  The furnace is then programmed to move farther
back on the sample, causing the bulk melt to come into contact
with the high-quality seed crystal, thus "seeding" the melt.
The seed crystal prescribes the growth orientation of the
crystal grown.  Having seeded the melt, the furnace translation
is reversed and the sample is directionally solidified at a
uniform velocity of 1.6 mm/h by moving the furnace and the
thermal gradient over the stationary sample.

      The USML-1 sample will be examined post-flight using
infrared and optical microscopy, microchemical analysis, X-ray
precision lattice parameter mapping and synchrotron topography,
infrared transmission, optical reflectance, photoconductance
and photoluminescence spectroscopy.  These characterization
techniques will quantitatively map the chemical, physical,
mechanical and electrical properties of the CGF flight crystal
for comparison with identically processed CGF ground samples.
These results will be compared quantitatively with the best
results accomplished terrestrially using the same growth
method.  Thermal, compositional and stress models will be
quantitatively compared to the experimental 1-g and
microgravity results.


Crystal Growth of Selected II-VI Semiconducting Alloys by
Directional Solidification

Principal Investigator:

Dr. Sandor L. Lehoczky
NASA Marshall Space Flight Center
Huntsville, Ala.

      The purpose of the experiment is to determine how the
structural, electrical and optical properties of selected II-VI
semiconducting crystals are affected by growth in a low-gravity
environment.  On USML-1, the PI will investigate mercury zinc
telluride (HgZnTe), with particular emphasis on compositions
appropriate for infrared radiation detection and imaging in the
8- to 12-micrometer wavelength region.  Infrared detection and
imaging systems at those wavelengths have the potential for use
in applications ranging from resource detection and management
on Earth to deep-space imaging systems.  On Earth, gravity-
induced fluid flows and compositional segregation make it
nearly impossible to produce homogeneous, high-quality bulk
crystals of the alloy.

      The PI will attempt to evaluate the effect of
gravitationally driven fluid flows on crystal composition and
microstructure and determine the potential role of irregular
fluid flows and hydrostatic pressure effects in causing crystal
defects.  The flight experiment should produce a sufficient
quantity of crystal to allow the PI to perform bulk property
characterizations and fabricate detectors to establish ultimate
material performance limits.

      The sample on USML-1 (Hg0.84Zn0.16Te) will be processed
using the directional solidification crystal growth method.
The hot zone of the CGF furnace will be 800!C for melting, and
the cold zone will be 350!C.  A portion of the sample will be
melted in the hot zone, and crystal growth will occur in the
resulting temperature gradient.  The furnace and thus, the
temperature gradient, will be moved slowly across the sample at
a rate of approximately 3.5 mm per 24 hrs.  The slow rate is
required to prevent constitutional supercooling ahead of the
solidification interface.

      The sample produced on USML-1 will be examined after the
mission for chemical homogeneity and microstructural perfection
by using a wide array of characterization techniques, including
optical and electron microscopy, X-ray diffraction, X-ray
topography and X-ray energy dispersion, infrared transmission
spectroscopy and galvanomagnetic measurements as a function of
temperature and magnetic field.  Selected slices from the
crystal will be used to fabricate device structures (detectors)
for further evaluation.


Study of Dopant Segregation Behavior During Growth of GaAs in
Microgravity

Principal Investigator:

Dr. David H. Matthiesen
GTE Laboratories Incorporated

      Typically, semiconductors have a very small amount of
impurity added to them to precisely engineer their material
properties.  These impurities, called dopants, are usually
added at a level of 10 parts per million.  Because of
convection in the melt on Earth, it is very difficult to
precisely control dopant distribution.  Inhomogeneity in dopant
distribution leads to widely varying material properties
throughout the crystal.  This experiment investigates
techniques for obtaining complete axial and radial dopant
uniformity during crystal growth of selenium-doped gallium
arsenide (GaAs).  GaAs is a technologically important
semiconductor used in a variety of applications, such as high-
speed digital integrated circuits, optoelectronic integrated
circuits and solid-state lasers.

      This experiment will use GaAs doped with selenium to
investigate the potential of the microgravity environment to
achieve uniform dispersal of the dopant during crystal growth.
The hot zone (1,260!C) and the cold zone (1,230!C) temperatures
are chosen to locate the 1,238!C melting point of GaAs in the
center of the gradient zone.

      The PI will analyze the USML-1 sample post-flight using a
variety of techniques, including electrical measurements by
Hall effect and capacitance-voltage techniques, chemical
measurements by glow discharge mass spectroscopy and optical
measurements by advanced quantitative infrared microscopy and
Fourier transform infrared spectroscopy.  These data will be
compared to current analytical and computer model based
theories.


Vapor Transport Crystal Growth of HgCdTe in Microgravity

Principal Investigator:

Dr. Heribert Wiedemeier
Rensselaer Polytechnic Institute, N.Y.

      This experiment will investigate the relationship between
convective flow, mass flux and morphology in mercury cadmium
telluride (HgCdTe) crystals.  HgCdTe crystals are useful as
infrared detectors for a variety of defense, space medical and
industrial applications.  Crystals free of large structural
defects and with a more even dispersion of the constituent
elements may improve detector performance.  To better
understand the factors that influence HgCdTe crystal growth,
this experiment will examine phenomena ranging from temperature
profiles to how the aspect ratio (shape) of the sample ampoule
affects mass transport and crystal growth.

      The USML-1 sample (Hg0.8Cd0.2Te) will be processed using
the vapor transport crystal growth technique.  The sample
material, sealed in one end of a quartz ampoule will be heated
to 625!C.  The vapors driven off will deposit as a crystal in
the cold zone (455!C).

      After the mission, the flight crystal will be examined
using X-ray diffraction, optical microscopy, scanning electron
microscope/wavelength dispersive spectroscopy, chemical
etching, Hall measurement and other techniques for evaluation
of morphology, structural perfection and properties of the
crystals.  The flight crystal may be used to fabricate an
infrared detector for further examination of its device
performance.  The PI will evaluate the temperature profile and
the geometry of the condensation region of the flight sample to
determine how these factors affect mass fluxes and crystal
morphology.  In addition, the PI will study how the aspect
ratio of the ampoule affects mass transport and crystal growth
properties.


ZEOLITE CRYSTAL GROWTH

Principal Investigator:

Dr. Albert Sacco
Worcester Polytechnic Institute

      NASA's Office of Commercial Programs (OCP) is sponsoring
the Zeolite Crystal Growth payload, developed by the Battelle
Advanced Materials Center, a NASA Center for the Commercial
Development of Space (CCDS) based in Columbus, Ohio, and the
Clarkson Center for Commercial Crystal Growth in Space, a CCDS
based in Potsdam, N.Y.

      The ZCG payload is designed to process multiple samples
of zeolite crystals, providing scientists with data on the most
efficient procedures and equipment for producing high-quality
zeolite crystals in space.

      Zeolite crystals are complex arrangements of silica and
alumina which occur both naturally and synthetically.  An open,
three-dimensional, crystalline structure enables the crystals
to selectively absorb elements or compounds.  As a result, the
crystals are often used as molecular sieves, making the
crystals highly useful as catalysts, filters, absorbents and
ion exchange materials.

      Zeolite crystals produced in space are expected to be
larger and more perfect than their ground-produced
counterparts, providing tremendous industrial potential for
space-produced crystals.  Ground-produced crystals are small in
size, causing severe disadvantages in absorption/separation and
ion exchange processes.  Knowledge gained through space-based
processing of large zeolites will provide a better
understanding of how zeolites act as catalysts, which could
result in the development of new ground-based catalysts.

      Current technology produces zeolite crystals using
chemical additives, however, if large zeolite crystals can be
produced without the need for additives, then the crystals
could be used effectively in membrane technology.  Such
membranes could result in major advantages over current
separation techniques and have potential for numerous
commercial applications.  In an attempt to grow such crystals
and to investigate optimal growth conditions, the ZCG
experiments on this mission will be processed in the middeck
and the Glovebox Module, an enclosed compartment that minimizes
risks to the experiments and the Spacelab environment.

      The ZCG experiment will be contained in a cylindrical ZCG
furnace assembly which fits into the space of two middeck
lockers and uses another locker for storage.  The furnace
consists of 19 heater tubes surrounded by insulation and an
outer shell.  Multiple samples will be processed in the furnace
using three independently-controlled temperature zones of 175
degrees C, 105 degrees C and 95 degrees C.

      The nucleus of the experiment will consist of 38
individually-controlled, metal autoclaves, each containing two
chambers and a screw assembly.  To activate the experiment, a
crew member will turn the screw assembly with a powered
screwdriver, pressurizing the solution in one chamber and
forcing it into the other.  Turning the screw assembly in the
opposite direction will pull the fluid back into the emptied
chamber.  By repeating this process several times, proper
mixing of the two solutions can be obtained (several different
mixing aids and nozzle designs are to be used on this mission).

      Other experiments conducted in the Glovebox Module will
use clear autoclaves to determine the proper number of times
the fluids should be worked to ensure proper mixing for each
design.  Once all of the autoclaves are activated and loaded
into the furnace assembly, a cover will be secured over the
front of the assembly and the furnace activated.  Once the
experiment is complete, the autoclaves will be removed and
stored for landing.  After the mission, scientists will examine
the crystals to determine which growth conditions were optimum.





FLUID PHYSICS EXPERIMENTS


Drop Physics Module (DPM)

NASA Jet Propulsion Laboratory
Pasadena, Calif.

      The DPM is a major microgravity instrument supporting
various experiments on the dynamics of fluids freed from the
influences of gravity and the walls of a container.

      Three Earth-based investigators will conduct experiments
using this system in USML-1:  Dr. Robert Apfel, Yale
University; Dr. Taylor Wang, Vanderbilt University and Dr.
Michael Weinberg, University of Arizona.  Serving as Payload
Specialist in USML-1 and co-investigator to the three
university scientists, Dr. Eugene Trinh will be the principal
operator of the DPM.

      The scientists will conduct pure-science studies to
investigate the internal and surface properties of liquids,
seeking to verify certain fluid-dynamics theories.  To get the
best match with theory, the scientists need to minimize the
influence of gravity which distorts the liquid's surfaces and
separates the material into layers of different density.

      Container walls also will distort the surfaces, whether
the liquid wets them or not, and introduce chemical
contamination.  The DPM uses computer-controlled sound waves in
a carefully-designed chamber, allowing the investigator to
position fluid drops free of the chamber walls, moving them,
spinning them and making them separate and flow together while
their dynamic properties are observed and recorded on videotape
and film.

      Scientific objectives of the DPM investigations include
testing and verifying theories describing the behavior of
vibrating drops stimulated by sound waves, measuring physical
properties of drop surfaces and studying the shapes of rotating
drops and their behavior as they split into double drops.
Other objectives involve understanding the dynamics of
coalescence, when two free drops merge.  Compound drops -- with
a drop of one type of liquid inside the main drop of another --
and air-filled liquid shells also will be studied for multiple
surface-tension effects and for spin dynamics.


Science and Technology of Surface-Controlled Phenomena

Principal Investigator:

Dr. Robert E. Apfel
Yale University

      Surface active materials (surfactants) play an important
role in industrial processes, from the production of cosmetics
to the dissolution of proteins in synthetic drug production to
enhanced oil recovery.  The PI will use the DPM to conduct two
sets of experiments to understand the effect of surfactants on
fluid behavior.

      The first experiment will investigate the surface
properties of single liquid drops in the presence of
surfactants.  Water drops will be positioned stably by the
acoustic field of the





Drop Physics Module.  The drop will be squeezed acoustically
and then released, exciting it so that it oscillates in a
quadruple shape.  The frequency and damping of the resulting
free oscillations will be measured.  The process will be
repeated both for varying surfactant concentrations and for
different surfactants.  These results will be analyzed to
determine the static and dynamic rheological properties of the
surface of liquid drops (e.g., surface viscosity, elasticity).
This set of experiments, coupled with the current theoretical
work of the science team, should give a better understanding of
the molecular-level forces acting in the surface layer of
simple water drops.

      In the second group of experiments, two water drops
containing varying concentrations of surfactants first will be
positioned stably at separate nodes of the Drop Physics Module
acoustic field.  They then will be brought slowly into contact
by carefully mixing acoustic modes to force the drops toward
each other.  If the drops do not coalesce spontaneously (which
will be the case as surfactant concentrations increase), a
combination of static squeezing and then forced oscillation
will be applied to the contacting drops with increasing
strength, inducing them to combine.  Both the parameters of the
induction techniques and the interface between the drops will
be measured during this process in an attempt to characterize
critical parameters that force the drops to rupture and
coalesce.  The PI will use the dual-drop coalescence experiment
to gain insight into the role of surfactants as "barriers" to
coalescence.  These experiments also may yield practical
knowledge by determining an energy-efficient approach to
enhancing drop coalescence.


Drop Dynamics Investigation

Principal Investigator:

Dr. Taylor G. Wang
Vanderbilt University

      Preliminary experiments using acoustic levitation to
suspend liquid drops were first completed in the Drop Dynamics
Module flown on the Spacelab-3 mission in 1985.  These
experiments not only confirmed some theories about drop
behavior but also provided unexpected results.  For example,
the bifurcation point -- when a spinning drop takes a dog-bone
shape to hold itself together -- came earlier than predicted
under certain circumstances.  On USML-1, the PI team will
attempt to resolve the differences between experiment and
theory using the more advanced capabilities of the Drop Physics
Module.  The PI also will use the DPM to study large-amplitude
oscillations in drop shape and the process of drop fission.

      Liquid drops (water, glycerin and silicone oil) between
0.5 to 2.7 cm in diameter will be deployed individually or in
groups in the experiment chamber at ambient temperatures and
pressures.  Sound waves directed at the drops will be varied in
frequency and intensity as drops are rotated, fused and made to
oscillate.  The equilibrium shapes of both charged and
uncharged liquids undergoing solid body and differential
rotation will be experimentally determined.  To determine the
equilibrium shapes of rotating drops, the relative phase
between the orthogonal acoustic waves used to position each
drop will be shifted by 90 degrees.  This phase shift will
create an acoustic rotational torque on the drop.

      The shape oscillation spectra of drops also will be
experimentally studied.  To determine the shape oscillation
frequency of both simple and compound drops, the acoustic field
will undergo carrier modulation to stimulate drop shape
oscillation.  The amplitude of the oscillation as a function of
the modulation frequency will be studied to determine the non-
linear behavior of the drop.  These data will allow the
equilibrium shapes and frequency spectrum of both simple and
compound liquid drops, undergoing different types of rotation
and oscillation, to be determined.

      Finally, the PI will use the DPM to conduct encapsulation
studies using sodium alginate and calcium chloride to determine
methods for centering one component of a compound drop.  In
this experiment, sodium alginate droplets will be injected into
a calcium chloride drop.  The resulting compound drop will be
subjected to various acoustic conditions to try to determine an
optimal method of forming uniform concentric spherical
membranes.


Measurement of Liquid-Liquid Interfacial Tension and the Role
of Gravity  in Phase Separation Kinetics of Fluid Glassmelts

Principal Investigator:

Dr. Michael C. Weinberg
University of Arizona

      The experiment explores a unique method for measuring an
important surface parameter -- the tension between interfaces
of drops and other materials.

      There are many liquid solutions that tend to separate
into several liquid phases when held in an appropriate
temperature range.  This same process occurs in many glass
systems, where it is referred to as glass-in-glass or liquid-
liquid phase separation, or amorphous immiscibility.  In both
liquids and glasses, the rates at which these phase separation
processes occur depend upon several factors, such as the
temperature and the characteristics of the surface at the
boundary between phases.  The measurement of the liquid-liquid
interfacial tension will provide one of the key quantities that
governs the rate of such a process.

      The experiment consists of measuring the liquid-liquid
surface tension of a compound drop consisting of two liquids
that do not mix.  A drop containing tracer particles is
deployed and then injected with an inner drop.  This compound
drop will be rotated in the Drop Physics Module at specified
angular velocities, and the shapes of both the inner and outer
drops will be distorted.  After equilibration of drop shape and
rotation rate, film images will be taken from two orthogonal
views to record the drops' new geometries.   Eight drop sets
will be examined (four liquid pairs, two drop radii ratios
each).  The photographs will be analyzed to determine the drop
distortions and will use theoretical models to calculate the
liquid-liquid surface tension between the substances that make
up each drop.


Astroculture(TM)

Principal Investigator:

Dr. Theodore W. Tibbitts
Wisconsin Center for the Commercial
Development of Space, Madison

      NASA's Office of Commercial Programs is sponsoring the
Astroculture(TM) payload, developed by the Wisconsin Center for
Space Automation and Robotics (WCSAR), a NASA Center for the
Commercial Development of Space (CCDS) based at the University
of Wisconsin in Madison.

      Currently, no satisfactory plant growth unit is available
for support of long-term plant growth in space.  Increases in
the duration of Space Shuttle missions have made it necessary
to develop plant growth technology that minimizes the costs of
life support while in space.  Plants can reduce the costs of
providing food, oxygen and pure water and also lower the costs
of removing carbon dioxide in human space habitats.

      Before plants can be grown in the Astroculture(TM) unit,
however, a series of experiments will have to be conducted on
the Space Shuttle to evaluate the critical subsystems (water
and nutrient delivery, lighting and humidity control) needed to
construct a reliable plant growth unit.  Water and nutrient
delivery will be tested and evaluated on STS-50, with
additional experiments added to future missions for evaluation
of the other two subsystems.

      The flight hardware for the STS-50 mission is self-
contained in a middeck locker and weighs approximately 70
pounds.  The Astroculture(TM) unit consists of a covered cavity
with two growth chambers containing inert material (having
particle size of 20 to 40 mesh) that serve as the root matrix;
a water supply system consisting of a porous stainless steel
tube embedded into the matrix, a water reservoir, a pump, and
appropriate valves for controlling the pressure flow of water
through the stainless steel tube; a water recovery system
consisting of the same components as the water supply system;
and a microprocessor system for control and data acquisition
functions.

      In orbit, the water supply and recovery systems will be
activated to initiate circulation of a nutrient solution
through the porous tubes.  Subsequently, the solution will move
through the wall of each porous tube into the matrix by
capillary forces.  In the matrix, the small pores will be
filled with the solution and the large pores with air, thereby
providing a non-saturated state.  The recovery system will
operate at several pressure levels to determine the rate at
which the solution will move through the matrix and the
capacity of the supply system to provide the solution to the
matrix.

      A computer system will monitor the amount of solution
pumped from the supply reservoir to the recovery reservoir.
Data collected by the computer will indicate the supply
system's overall capacity for replacing water and nutrients
removed by plants growing in microgravity.


SURFACE TENSION DRIVEN CONVECTION EXPERIMENT (STDCE)

Principal Investigator:

Dr. Simon Ostrach
Case Western Reserve University, Ohio

      On Earth, buoyancy-driven flows and convection impede
attempts to grow better crystals and solidify new metals and
alloys.  Ground-based and preliminary space experiments have
shown that variations in surface tension, caused by temperature
differences along a liquid's free surface, generate
thermocapillary fluid flows.  Although thermocapillary flows
exist on Earth, they are masked by stronger buoyancy-driven
flows.  In low-gravity, buoyancy-driven flows are reduced,
making it easier to examine thermocapillary flows.  Earth's
gravity also alters the liquid free surface shape and damping
characteristics of any fluid.  The microgravity environment
allows researchers to study the impact of a variety of curved
free surface geometries on thermocapillary fluid flows.

      The USML-1 Surface Tension Driven Convection Experiment
(STDCE) will  obtain quantitative data on thermocapillary flows
over a wide range of parameters in experiments that vary the
imposed surface temperature distributions (thermal signatures)
and the configuration of the liquid's free surface.  For USML-
1, both steady flows (those that do not change over time) and
transient flows (those that do change over time) will be
studied.  A variety of conditions and experiment configurations
will be used, and an attempt will be made to identify the
conditions for the onset of oscillations.
      The experiments will be conducted in the Surface Tension
Driven Convection Experiment Apparatus, which consists of an
experiment package and an electronics package located in a
double Spacelab rack.  The experiments are carried out in a
cylindrical container (10 cm in diameter and 5 cm high).  A
lightweight  silicone oil is used as the test fluid because it
is not susceptible to surface contamination, which can ruin
surface tension experiments.  The experiment package contains
the test chamber, made of copper to assure good thermal
conductivity along the walls, and the silicone oil system,
consisting of a storage reservoir and a fluid management system
for filling and emptying the test chamber.
      Two heating systems, which provide the different thermal
signatures, are part of the test chamber.  A submerged
cartridge heater system will be used to study thermocapillary
flows over a range of imposed temperature differences.  A
surface heating system will be used to investigate fluid flows
generated by various heat fluxes distributed across the surface
of the liquid.  This heating system consists of a CO\s\do2(2)
laser and optical elements that direct the laser beam to the
test chamber and vary the imposed heat flux and its
distribution.
      To visualize the fluid flows in the test chamber, a laser
diode and associated optical elements will illuminate aluminum
oxide particles suspended in the silicone oil, and a video
camera, attached to a chamber view port, will record the
particle motion.  A scanning infrared imaging system records
oil surface temperature.  Thermistors inside the test chamber
measure bulk oil temperatures.  The crew can use a Spacelab
camera mounted to the front of the chamber to monitor oil
filling and draining, submerged heater positions and oil
surface shapes and motions.  These data will be downlinked to
the Spacelab Payload Operations Control Center at the Marshall
Space Flight Center.  Based on the analysis of the data, a new
set of test parameters for the next series of experiments will
be uplinked to the experiment computer in the Spacelab.  From
the data obtained, the PI will correlate velocity and
temperature distributions with imposed thermal conditions to
complete mathematical models of thermocapillary flow.



COMBUSTION SCIENCE EXPERIMENT

SOLID SURFACE COMBUSTION EXPERIMENT (SSCE)

Principal Investigator:

Robert A. Altenkirch
Mississippi State University

      The Solid Surface Combustion Experiment (SSCE) is a major
study of how flames spread in microgravity.  Comparing data on
how flames spread in microgravity with knowledge of how flames
spread on Earth may contribute to improvements in all types of
fire safety and control equipment.  This will be the fifth time
SSCE has flown aboard the Shuttle.  Ultimately, plans call for
SSCE to fly a total of eight times, testing the combustion of
different materials under different atmospheric conditions.

      In the SSCE planned for USML-1, scientists will test how
flames spread along a sample of Plexiglas in an artificial
atmosphere containing oxygen mixed with nitrogen.

      During the other four missions on which this experiment
was flown, samples of a special filter paper were burned in
atmospheres with different levels of oxygen and pressure.  The
special filter paper and Plexiglas were chosen as test
materials because extensive databases already exist on the
combustion of these materials in Earth's gravity.  Thus,
combustion processed on Earth and in space can be readily
compared.

      Scientists will use computer image enhancement techniques
to analyze the film record of the Solid Surface Combustion
Experiment.  They then will compare the enhanced images and
recorded temperature and pressure data with a computer
simulation of the flame spreading process.  Reconciling the two
sets of data is expected to provide new insights into the basic
process of combustion.


BIOTECHNOLOGY EXPERIMENTS


PROTEIN CRYSTAL GROWTH  (PCG)

Principal Investigator:

Dr. Charles E. Bugg
University of Alabama at Birmingham

      NASA's Office of Commercial Programs (OCP) is sponsoring
the Protein Crystal Growth (PCG) payload, developed by the
Center for Macromolecular Crystallography (CMC), a NASA Center
for the Commercial Development of Space (CCDS) based at the
University of Alabama at Birmingham.

      The objective of the PCG experiments is to produce large,
well-ordered crystals of various proteins.  These crystals will
be used in ground-based studies to determine the three-
dimensional structures of the proteins and to investigate the
kinetics of crystal growth and the impact of fluid disturbances
on crystal growth.

      Since proteins play an important role in everyday life --
from providing nourishment to fighting disease -- research in
this area is quickly becoming a viable commercial industry.
Scientists need large, well-ordered crystals to study the
structure of a protein and to learn how a protein's structure
determines its functions.

      The technique most-widely used to determine a protein's
three-dimensional structure is X-ray crystallography, which
requires large, well-ordered crystals for analysis.  Crystals
produced on Earth often are large enough to study, but usually
they have numerous gravity-induced flaws.  However, space-
produced crystals tend to be purer and have more highly-ordered
structures which significantly facilitates X-ray diffraction
studies of the crystallized proteins.

      Studies of such crystals not only can provide information
on basic biological processes, but they could lead to the
development of food with higher protein content, highly
resistant crops and more effective drugs.  By studying the
growth rates of crystals under different conditions, scientists
can find ways to improve crystal growth in microgravity, thus
providing higher-quality crystals for study and the ability to
produce large crystals made of hard-to-grow proteins.  For
these reasons, PCG activities have been conducted on 14 Shuttle
missions counting STS-49.

      On STS-50, the flight hardware will include two
Refrigerator/Incubator Module (R/IM) thermal enclosures and one
newly-designed thermal enclosure, called the Commercial R/IM
(CRIM).  The CRIM allows for a pre-programmed temperature
profile and a feedback loop that monitors CRIM temperatures
during flight.

      To optimize protein crystal growth conditions, some of
the PCG experiments will be conducted in the Glovebox Module,
an enclosed compartment that minimizes risk to the experiments
and the Spacelab environment.  Prior to being activated, the
experiments will be stowed in a R/IM set at 22 degrees C.  The
experiments will be conducted using modular crystal growth
hardware and will include as many as 21 different proteins.
Experiment parameters will be altered in response to crew
observation of the crystal growth process.  New experiments
will be initiated throughout the mission to take advantage of
lessons learned from early experiment runs.  As the PCG
activities in the Glovebox are completed, the experiments will
be returned to the 22-degree R/IM.

      Other PCG experiments will be stowed in the other R/IM,
also set at 22 degrees C, and the CRIM, set at 4 degrees C.
Each will contain three vapor diffusion apparatus (VDA) trays
with 20 individual growth chambers.  One side of each tray
holds 20 double-barreled syringes, while the other side holds
plugs that cap the tips of the syringes.  Protein solution will
be stored in one barrel of each syringe, and the other will
house precipitant solution.  A reservoir of concentrated
precipitant solution surrounds each syringe inside the crystal
growth chamber.

      To activate the experiment, a crew member will attach a
handwheel to a ganging mechanism on the plug side of each VDA
and turn it to retract the plugs from the syringe tips.  The
handwheel then will be moved to the ganging mechanism on the
syringe side of the tray, where it will be turned to extrude
the protein and precipitant solutions to form a drop on the tip
of each syringe.  The difference in concentration of the
precipitant in the reservoir and the drop causes water
molecules to migrate from the drop through the vapor phase into
the reservoir solution.  As the concentration of protein and
precipitant increase in the drop, crystal growth will begin.

      Twenty of the growth chambers are designed to accommodate
crystal seeding.  During the second flight day, a crew member
will open a port on 10 of the seeding chambers in the VDA R/IM
and inject each protein drop with a few microliters of solution
containing Earth-grown "seed" crystals.  The operation will be
repeated on the third flight day with the remaining 10 seeding
chambers.  Inserting seed crystals into the protein droplets is
expected to initiate immediate growth of protein crystals.

      At the end of the mission, the experiments will be
deactivated.  Due to each protein's short lifetime and the
crystals' resulting instability, the PCG payload will be
retrieved from the Shuttle within 3 hours of landing and
returned to the CMC CCDS for post-flight analyses.

      Of the 34 proteins selected to fly on this mission, 60
percent have flown on previous flights.  Nine of the proteins
are OCP-sponsored and have commercial co-investigators that are
affiliates of the CMC CCDS.  Many have potential commercial
application in the pharmaceutical industry.  Structural
information gained from these experiments may provide better
understanding of the immune system, the function of individual
genes and treatment of disease, and many ultimately aid in the
design of a specific, effective and safe treatment of viral
infections.

      Dr. Lawrence J. DeLucas, Associate Director for PCG at
the CMC CCDS, is a co-investigator and a payload specialist on
the STS-50 mission, providing on-site scientific management of
the PCG experiments.





GENERIC BIOPROCESSING APPARATUS

Principal Investigator:

Dr. Michael C. Robinson
Bioserve Space Technologies
University of Colorado in Boulder

      NASA's Office of Commercial Programs is sponsoring the
Generic Bioprocessing Apparatus (GBA) payload, developed by
Bioserve Space Technologies, a NASA Center for the Commercial
Development of Space (CCDS) based at the University of Colorado
in Boulder.

      The GBA is a multi-purpose payload that supports mixing
of fluids and solids in up to 500 individual sample containment
devices, called Fluids Processing Apparatuses (FPAs), in
microgravity.  On STS-50, 23 different experiments will be
conducted in 132 FPAs.

      Some of the experiments will be stowed in a middeck
Refrigerator/Incubator Module (R/IM), while others will be
stowed in an ambient temperature stowage locker in the Spacelab
module.  Of the 23 experiments, one (called Directed
Orientation of Polymerizing Collagen Fibers) will be processed
in the Glovebox Module, an enclosed compartment that allows
sample manipulation with minimal risks to the experiments and
the Spacelab environment.

      A crew member will activate a batch of 12 FPAs by mixing
sample materials and inserting them into the GBA for
incubation.  A computer will automatically terminate incubation
after a preprogrammed duration.  A crew member then will remove
the samples from the GBA, restow them in either the R/IM or
Spacelab stowage locker and load another batch of samples for
incubation.

      For a number of samples, on-orbit video recordings will
be obtained to document sample behavior and morphology.  The
GBA will monitor and control its own temperature, and it will
monitor optical density to provide information on processing
rates and cell growth.

      The GBA will allow scientists to study an array of
biological processes, with samples ranging from molecules to
small organisms.  Some of the many commercial experiments
currently scheduled to fly in the GBA include:

     Artificial Collagen Synthesis -- the ability to
artificially synthesize collagen fibers in microgravity could
result in materials that have the strength and properties of
natural collagen.  Synthesized collagen could be used more
effectively as artificial skin, blood vessels, and other parts
of the body.

     Assembly of Liposomes and Virus Capsid (two types of
spherical structures that could be used to encapsulate
pharmaceuticals) -- the ability to properly assemble liposomes
and virus capsid in microgravity could result in using them to
navigate drugs to specific body tissues, such as tumors.
     Development of Brine Shrimp and Miniature Wasps in
Microgravity -- could shed light on the importance of gravity
in human development and aging and potential components of a
Controlled Ecological Life Support System (CELSS).

     Seed Germination and Development -- could help develop
technology for growing plants in space and provide knowledge
for use in agriculture on Earth.

      The ability to process such a large quantity of different
samples truly exemplifies the GBA as a multi-purpose facility,
helping to answer important questions about the relationship
between gravity and biology.  The GBA will be instrumental in
evaluating the commercial potential of space-based biomaterials
processes and products.



Glovebox


      The USML-1 Glovebox (GBX), provided by the European Space
Agency, is a multiuser facility supporting 16 experiments in
fluid dynamics, combustion science, crystal growth and
technology demonstration.  Some of the experiments will provide
information that other USML-1 investigations will use
immediately during the mission to refine their experiment
operations.  Others will provide data that may be used to
define future microgravity science investigations.

      The GBX has an enclosed working space that minimizes the
contamination risks to both Spacelab and experiment samples.
The GBX working volume provides two types of containment:
physical isolation from the Spacelab and negative air pressure
differential between the enclosure and the Spacelab ambient
environment.  An air-filtering system also protects the crew
from harmful experiment products.  The crew manipulates
experiment equipment through three doors:  a central port
through which experiments are placed in the working volume and
two glove doors.  When an airtight seal is required, the crew
inserts their hands into rugged gloves attached to the glove
doors.  If an experiment requires more sensitive handling, the
crew may don surgical gloves and insert their arms through a
set of adjustable cuffs.

      Most of the GBX experiment modules have magnetic bases
that hold them to the steel floor of the enclosure. Others
attach to a laboratory jack that can position the equipment at
a chosen height above the cabinet floor.  Equipment also may be
bolted to the left wall of the working volume or attached
outside the GBX with Velcro(TM).

      The GBX supports four charge-coupled device (CCD)
cameras, two of which can be operated simultaneously.  Three
black-and-white and three color camera CCD heads are available.
Operations can be viewed through three view-ports or through a
large window at the top of the working volume.  The GBX also
has a backlight panel, a 35-mm camera and a stereomicroscope
that offers high-magnification viewing of experiment samples.
Video data can be downlinked in real-time.  The GBX also
provides electrical power for experiment hardware, a time-
temperature display and cleaning supplies.





Passive Accelerometer System (PAS)

Dr. J. Iwan D. Alexander
The University of Alabama in Huntsville

      The objective of PAS is to test a simple system to
measure residual acceleration caused by atmospheric drag
effects and the gravity gradient from the spacecraftUs center
of mass.  Because many microgravity experiments and processes
are sensitive to accelerations, it is important to measure
these accelerations to improve the design of future experiments
and facilities.  A proof mass (steel ball) will be placed in a
glass tube full of water.  This tube is contained in a lexan
sleeve and will be mounted parallel to the flight direction.
An astronaut tracks its position manually every 1-2 minutes,
using a ruler and protractor, repositioning the tube if the
angular deviation of the proof mass exceeds 10!.  StokesU law
will be used to indirectly calculate the residual acceleration
from the ballUs trajectory and speed.  Each run will take
approximately 20 minutes.  This experiment will be repeated 5-
10 times during the mission, at several different locations in
middeck and the Spacelab.


Interface Configuration Experiment  (ICE)

Dr. Paul Concus
University of California at Berkeley and Lawrence Berkeley
Laboratory

      ICE will explore the behavior of liquid-vapor interfaces
that has been predicted mathematically for certain irregularly
shaped "exotic" containers in a low-gravity environment.  By
demonstrating the ability to mathematically predict the shape
and location of liquids in exotic containers, the researchers
hope to build confidence in the ability to predict fluid
configurations in containers of all shapes.

      ICE has been designed to observe:

     The location and relative stability of surface shapes in
mathematically designed containers

     The effects of container surface conditions on fluid
behavior

     The effects of fluid properties on fluid behavior


Protein Crystal Growth Glovebox (PCGG)

Dr. Lawrence J. DeLucas
The University of Alabama at Birmingham

      This experiment will be flown by the Center for
Macromolecular Crystallography, a NASA Center for the
Commercial Development of Space (CCDS) based at the University
of Alabama at Birmingham (UAB).  Individual protein crystal
growth experiments are jointly sponsored by the Office of
Commercial Programs and the Microgravity Science and
Applications Division, Office of Space Science and
Applications.

      The objectives are to identify optimal conditions for
nucleating and growing protein crystals in space and to
investigate ways of manipulating protein crystals in
microgravity.  By determining the structure of protein
crystals, scientists may be able to develop dramatically
improved medical and agricultural products.   More information
is needed about optimum mixing times, solutions concentrations
and other growth parameters for future microgravity protein
crystal growth experiments.

      The PCGG investigator, Dr. Lawrence J. DeLucas, is a
USML-1 payload specialist.  He and other crew members will
conduct 720 interactive experiments using modular crystal
growth hardware and including as many as 21 different proteins.
Sample materials will be stored in a middeck R/IM for launch.
Protein crystals will be grown by vapor diffusion and free
interface diffusion methods.  Graduated syringes with
dispensing devices will be used to extrude precise amounts of
proteins, buffers or precipitates.  Seed crystals will be
injected into equilibrated protein/precipitant solutions using
micro-manipulators.  The GBX microscope and a PCGG light table
will be used to inspect growing crystals.  Experiment
parameters will be altered in response to crew observations of
the crystal growth process.  New experiments will be initiated
throughout the mission to take advantage of lessons learned
from early experiment runs.  Crew members also will study ways
to manipulate protein crystals and mount them in capillaries.


Solid Surface Wetting Experiment  (SSW)

Dr. Eugene H. Trinh
NASA Jet Propulsion Laboratory, Pasadena, Calif.

      The objective is to determine the most reliable injector
tip geometry and coating for droplet deployment for Drop
Physics Module (DPM) experiments.  Fluids experiments in the
DPM depend on efficient and accurate deployment of droplets of
the proper volume and shape.  Different combinations of fluids
and injector nozzles will be used to deploy droplets inside the
GBX working area.  A micrometer drive will provide calibrated
volume control of the manual injection syringe.  The crew will
test three different compositions of water-glycerol mixtures,
as well as a variety of silicon oils.  A coaxial injector will
be used to inject air bubbles into some drops, so shells can be
studied.  Video data of droplet deployment will be recorded for
post flight analysis.  The crew also will measure droplet
volume and wetting angles during the tests.


Marangoni Convection in Closed Containers (MCCC)

Dr. Robert J. Naumann
The University of Alabama in Huntsville

      The objective is to determine under what conditions (if
any) surface tension driven convection can occur in closed
containers.  A liquid in space may not conform to the shape of
its container.  It may be possible for Marangoni convection to
occur along all free surfaces of a liquid.  If so, models of
Marangoni convection effects on heat transfer and fluid motion
in space must be refined.  Two glass ampoules will be tested,
one with water and one with silicone oil, both containing glass
tracer beads.  Each ampoule has a set of heaters and
thermistors.  The crew will record the onset of Marangoni
convection during heating with video and the 35mm camera.
Smoldering Combustion in Microgravity (SCM)

Dr. A. Carlos Fernandez-Pello
University of California at Berkeley

      The SCM experiment will study the smoldering
characteristics of a polyurethane foam in environments with and
without air flows.  Specifically, the experiment will:

     Measure how different air flows and ignitor geometries
affect the smolder propagation rates and the smolder
temperatures.

     Measure the ignition energy required in low gravity as
compared to Earth's gravity.

     Observe the potential transition from smoldering to
flaming, the transition from smoldering to extinction and
conditions leading to the transition.

      Data gathered from the experiment will help scientists
develop computer models of smoldering combustion processes and
explore ways to control smoldering combustion in low gravity.
Ultimately, this experiment will improve methods of fire
prevention, detection and extinguishment aboard spacecraft and
possibly on Earth.


Wire Insulation Flammability Experiment (WIF)

Paul Greenberg
NASA Lewis Research Center
Cleveland, Ohio

      The WIF experiment is designed to determine the
offgassing, flammability and flame spread characteristics of
overheated wire in a low gravity environment.

      Extensive studies of the relationship between the
electrical current passed through a wire and the heating of the
wire have led to the development of building codes and
insulation materials that minimize the number and severity of
wiring-related fires.  To support the development of similar
"building codes" for future space-based structures, the WIF
will study the warming of electrical wire in microgravity.


Candle Flames in Microgravity

Dr. Howard Ross
NASA Lewis Research Center
Cleveland, Ohio

      This experiment is expected to provide new insights into
the combustion process.
Specifically, this experiment is designed to:

     Determine if candle flames can be sustained in a purely
diffusive, very still environment or in the presence of air
flows smaller than those caused by buoyancy on Earth.

     Determine how the absence of buoyant convection affects
the burning rate, flame shape and color of candle flames.

     Study the interactions between two closely spaced candles
in microgravity.

     Determine if candle flames spontaneously oscillate before
they go out in the absence of buoyancy-induced flows.

      For the first test, the crew member will remove a candle
and ignitor from the candle parts box and install them inside
the glovebox.  After making and verifying the electrical
connections, the crew member will set up video cameras at the
top and one side of the glovebox to focus on the area around
the candle tip and the displays of thermocouple data.

      After starting the camera and instruments, the crew
member will activate the ignitor which will light the candle.
Photography and temperature measurements will continue until
the flame burns out or until a fixed period of time passes.
The crew member then will turn on the glovebox fan to cool the
candle box and replenish the glovebox with air.  After about 1
minute, the next test can proceed.  There will be a total of
four tests conducted.


Fiber Pulling in Microgravity  (FPM)

Dr. Robert J. Naumann
The University of Alabama in Huntsville

      The objective is to test a variety of techniques to pull
fibers in microgravity.  On Earth, gravity drainage and
Rayleigh-Taylor instabilities cause thin columns of low-
viscosity liquids to break apart or form beads.  In space, it
should be possible to determine which of the two influences is
the limiting factor in fiber pulling and whether certain low-
viscosity materials could be more efficiently processed in
microgravity.  Simulated glass melts of different viscosities
will be extruded from syringes to simulate the drawing of a
fiber.  The time for the breakage of the fibers will be
determined.  There are six syringe sets with decreasing ratios
of viscosity to surface tension.  One video camera will observe
the apparatus, while the other camera will use a high
resolution macro lens to focus on the pulled fibers.


Nucleation of Crystals from Solutions in a Low-g
Environment (NCS)

Dr. Roger L. Kroes
NASA Marshall Space Flight Center
Huntsville, Ala.

      The objective is to test a new technique for initiating
and controlling the nucleation of crystals from solution in
reduced gravity.  Improvements in the ability to control the
location and time of the onset of nucleation of crystals in a
solution have the potential to increase the flexibility of all
space experiments involving solution crystal growth.  A mildly
supersaturated solution will be injected with a fixed amount of
warmer solution in a crystal growth test cell.  The injected
solution will be more concentrated than the host solution and
will initiate nucleation.  The nucleation process will be
recorded on the GBX video system.  Solutions of triglycine
sulfate, L-Arginine phosphate and potassium aluminium sulphate
will be tested.  At the conclusion of each test, any crystals
produced will be removed and stored for post-flight analysis.


Oscillatory Dynamics of Single Bubbles and Agglomeration in an
Ultrasonic Sound Field in Microgravity (ODBA)

Dr. Philip L. Marston
Washington State University

      The objective is to explore how large and small bubbles
behave in space in response to an ultrasound stimulus.  By
understanding how the shape and behavior of bubbles in a liquid
change in response to ultrasound, it may be possible to develop
techniques that eliminate or counteract the complications that
small bubbles cause during materials processing on earth.  A
variety of bubble configurations will be tested in a sealed
water chamber.  An ultrasonic transducer will be attached to
the chamber to establish an ultrasonic standing wave.  The wave
will drive the bubbles into shape oscillations.  Bubbles will
be brought into contact by either the ultrasonic field or
direct mechanical manipulation.  The coalescence and resulting
decay of large amplitude shape oscillations will be recorded on
video.  The response of bubbles to a surfactant solution --
sodium dodecyl sulfate -- also will be tested.


Stability of a Double Float Zone (DFZ)

Dr. Robert J. Naumann
The University of Alabama in Huntsville

      The objective is to determine if a solid cylinder can be
supported by two liquid columns and remain stable in
microgravity.  It may be possible to increase the purity and
efficiency of glass materials with a newly patented technique
that relies on a solid column of material supported by two
liquid columns of its own melt.  If this arrangement can be
maintained in microgravity, space may be a suitable laboratory
for such processing.  A variety of double float zone
configurations will be tested using lexan rods of different
sizes and with different end geometries.  A center rod will be
supported between two other rods by a float zone made of dyed
water.  The oscillations and breakup of the fluid as the two
outer rods are moved will be recorded on video.


Oscillatory Thermocapillary Flow Experiment (OTFE)

Dr. Simon Ostrach
Case Western Reserve University

      The objective is to determine the conditions for the
onset of oscillations in thermocapillary flows in silicone
oils.  Temperature variations along a free surface generate
thermocapillary flows in the bulk liquid.  On Earth, the flows
become oscillatory under certain conditions.  By determining
the conditions present when oscillations begin in microgravity
and comparing them to oscillatory onset conditions on Earth,
scientists will gain insight into the cause of the
oscillations.  Four cell/reservoir modules will be tested (two
different sizes, using two different viscosities of silicone
oil).  Micron-sized aluminium oxide tracer particles will be
mixed with the fluid in the reservoir.  The fluid will then be
transferred to the test cell.  The crew member manipulates the
cell to obtain a fluid free surface.  The fluid then is heated
by a wire heating element in the center of the test cell.
Three thermocouples measure the temperature at the wall, heater
and in the fluid.  Three video cameras will record the free
surface behavior and the thermocouple readings.


Particle Dispersion Experiment  (PDE)

Dr. John R. Marshall
NASA Ames Research Center
Mountain View, Calif.

      The PDE will determine the efficiency of air injection as
a means of dispersing fine particles in a microgravity
environment.  The experiment will serve as a simple trial run
for particle dispersion experiments in the Space Station Gas-
Grain Simulation Facility.  The dispersion particles also will
be studied for their tendency to electrostatically aggregate
into large clusters.

      Electrostatic aggregation is an important process for
cleansing planetary atmospheres after major dust storms,
volcanic eruptions and meteorite/comet impact.  Major
biological/geological events such as the extinction of the
dinosaurs have been attributed to the occlusion of sunlight by
dust in the atmosphere after a meteorite impact.  This climate
effect depends on the time the dust stays aloft, which in turn
depends upon the rate and mode of dust aggregation; hence the
importance of understanding the nature of the aggregation
process.

      The PDE consists of a pump unit for generating compressed
air and eight small experiment modules.  An experiment involves
connecting a module to the pump, pressurizing the pump by
operation of a hand crank and sudden release of the compressed
air into the module which forcefully injects a stream of small
particles into the 2 x 2 x 2 inch cubic experiment volume of
the module.  The injection force disaggregates the particles
and disperses them throughout the complete module volume.  This
process is filmed on video through one of two windows in the
module.  After this dispersion technique is tested, the
particles will be monitored as they float freely in the
experiment chamber and eventually aggregate into large
clusters.  The rapidity of aggregation and the mode of
aggregation (sphere or chain formation) are of prime interest.
This process is repeated for all modules.  The eight modules
allow for eight different tests that vary particle size and
particle mass.


Directed Polymerization Apparatus (DPA):  Directed Orientation
of  Polymerizing Collagen Fibers

Dr. Louis S. Stodieck
Center for Bioserve Space Technologies
Colorado University, Boulder

      This experiment is provided by the Center for Bioserve
Space Technologies, a NASA Center for the Commercial
Development of Space (CCDS) based at the University of
Colorado, Boulder.  The objective is to demonstrate that the
orientation of collagen fiber polymers can be directed in
microgravity in the absence of fluid mixing effects.  Collagen
fibers have potential uses as synthetic implant materials. The
orientation of collagen fiber polymers is critical to their
functions, and gravity-driven mixing on Earth interferes with
the ability to direct the orientation of these fibers.
Collagen samples will be processed using a Directed
Polymerization Apparatus.  Eight samples will be activated on
orbit in the GBX.  Four will be subjected to weak electric
currents to direct the orientation of the collagen fibers
during assembly.  Four samples will not be exposed to the
current and will act as controls.  After processing, the
samples will be stored in a Refrigerator/Incubator Module.


Zeolite Glovebox Experiment  (ZGE)

Dr. Albert Sacco
Worcester Polytechnic Institute

       The Zeolite Crystal Growth experiment will be provided
by the Battelle Advanced Materials Center, Columbus, Ohio, and
the Clarkson Center for Commercial Crystal Growth in Space,
Potsdam, New York, both of which are NASA Centers for the
Commercial Development of Space (CCDS).  The objective is to
examine and evaluate mixing procedures and nozzle designs that
will enhance the middeck Zeolite Crystal Growth experiment.
Twelve self-contained, cylindrical, Plexiglas/Teflon(TM)
autoclaves will be used to test three different mixer (nozzle)
designs and four mixing protocols.  Each autoclave is a sealed
container containing silicate and aluminium solutions in
separate volumes.  The fluids are mixed by using a screwdriver
to drive a piston into one volume, forcing the fluid through an
opening to mix with the fluid in the second volume.  Operations
with the twelve autoclaves will be recorded on video.


SPACE ACCELERATION MEASUREMENT (SAMS)

Principal Investigator:

Charles Baugher
NASA Lewis Research Center
Cleveland, Ohio

      The Space Acceleration Measurement System (SAMS) is
designed to measure and record low-level acceleration that the
Spacelab experiences during typical on-orbit activities.  The
three SAMS sensor heads are mounted on or near experiments to
measure the acceleration environment experienced by the
research package.  The signals from these sensors are
amplified, filtered and converted to digital data before being
stored on optical disks.

      For the first USML-1 mission, the main unit of the Space
Acceleration Measurement System will be mounted in the center
aisle of the Spacelab module, near the aft end of the module.
Its three remote sensor heads will be mounted on the Crystal
Growth Furnace experiment, Surface Tension Driven Convection
Experiment and the Glovebox Experiment Module.

      SAMS flight hardware was designed and developed in-house
by the NASA Lewis Research Center.



EXTENDED DURATION ORBITER MEDICAL PROJECT (EDOMP)

Project Manager:

J. Travis Brown
NASA Johnson Space Center, Houston

       A series of medical investigations are included in the
STS-50 flight plan to assist in the continuing development of
countermeasures to combat adverse effects of space flight.

       The upward shift of body fluids and slight muscle
atrophy that occurs in space causes no problems while
astronauts are in space.  Researchers are concerned, however,
that the readaptative processes occurring immediately upon
return to Earth's gravity could hinder the crew in an emergency
escape situation.

       The Extended Duration Orbiter Medical Project, sponsored
by the Johnson Space Center's Medical Science Division, will
validate countermeasures for longer duration flights.  EDOMP
will have middeck investigations and pre- and post-flight
investigations to assess the medical status of the crew
following 13 days of exposure to microgravity.  Three
experiments selected for Spacelab use will involve Lower Body
Negative Pressure, Variability of Heart Rate and Blood Pressure
and a Microbial Air Sampler.


Lower Body Negative Pressure (LBNP)

       During early phases of a mission, observers notice that
crew members' faces become puffy due to fluid shifting from the
lower body toward the head and chest in the absence of gravity.
While it is not a problem on orbit, the fluid shift and
resultant fluid loss, although appropriate for microgravity,
can pose potential problems upon return to Earth.  Crew members
may experience reduced blood flow to the brain when standing
up.  This could lead to fainting or dizziness.  The
investigators hypothesize that redistributing body fluids
through exposure to Lower Body Negative Pressure in conjunction
with fluid loading and salt tablets will improve this situation
and help prevent fainting.  The benefit is believed to remain
in the body for 24 hours after the last treatment.

       The LBNP experiment uses an inflatable cylinder which
seals around the waist.  The device is tethered to the floor of
the Spacelab and stands 4 feet tall.  A vent to the Spacelab
vacuum is used to apply negative pressure to the device after
the crew member is inside.  The pressure is gradually
decreased, drawing fluids to the lower body and somewhat
offsetting the upward fluid shift that occurs upon entry to
microgravity.  A controller is used to automatically reduce and
increase the pressure according to a preset protocol.
Measurements of heart dimensions and function, heart rate and
blood pressure will be recorded.  Leg volume measurements will
be performed before and after each protocol using the LBNP
device.  The data collected will be analyzed to determine the
physiological changes in the crew members and the effectiveness
of the treatment.  The result of the procedure is expected to
be an increased tolerance of orthostasis -- or standing upright
-- upon return to Earth's gravity.

       LBNP has been used a number of times in the U. S. space
program, first during the Skylab missions.  STS-50 will be the
fourth flight of the current collapsible unit.  Researchers are
refining the LBNP protocol which will be used operationally on
future 13- through 16-day missions.


Variable Heart Rate and Blood Pressure

       On Earth, many factors affect our heart rate and blood
pressure.  These include job stress, specific activity and
diet.  There are changes between our sleeping and waking
states, known as diurnal variation.  While emotions and normal
body cycles cause a majority of these fluctuations, gravity
plays a role.  This study will determine if blood pressure and
heart rate exhibit more or less variability in microgravity
than on Earth.  The study also will determine whether a change,
if any, correlates with the reduction in sensitivity of
baroreceptors in the carotid artery located in the neck.
Baroreceptors are one of the body's blood pressure sensors used
to regulate blood pressure and heart rate.

       Crew members will wear portable equipment including an
Automatic Blood Pressure Monitor and a Holter Recorder system
that continuously records ECG while periodically monitoring
blood pressure in the arm.  The data collected are analyzed
after the mission.


Microbial Air Sample

       Although all materials that go into the Shuttle are as
clean as possible, bacteria and fungi growth have been detected
in missions of 6-10 days duration.  The growths were minimal
and posed no health risk to the crew.

       The microbial air sampler is a small device that will be
placed in several areas of the Spacelab for air sampling.  Agar
strips will be inserted into the device for collection of
microbes.  Postflight analysis of the agar strips will quantify
the fungal and bacterial growth from this 13-day mission.


Isolated/Stabilized Exercise Platform

       One of the major challenges faced in the STS-50/USML
mission is the incompatibility of astronauts who need to
perform vigorous exercise to maintain their health while at the
same time sensitive microgravity experiments which need to be
in an environment free from disturbances.  The solution to this
problem is a device called the Isolated/Stabilized Exercise
Platform (ISEM) which supports the use of exercise equipment
yet cancels out the inherent vibrations.

       Lockheed designed the first ISEP for use with an
ergometer, a stationary-cycle device built by the European
Space Agency.  Future designs will accommodate a treadmill and
a rowing machine.

       The ISEP consists of four rectangular stabilizers
attached vertically to
a frame, which rests on shock absorbers called isolators.  The
ergometer attaches to the frame.  The stabilizers hold each
corner of the frame stationary.  A motor inside each stabilizer
uses inertial stabilization to counteract the disturbances
caused by exercise.

       Without stabilizers, a crew member peddling a stationary
bike can produce as much as 100 pounds of force, which far
exceeds the allowable microgravity disturbance limits set by
NASA.  With the ISEP system, the exercise is expected to cause
less than 1 pound of disturbance force on the Shuttle middeck.


Investigations into Polymer Membrane Processing

Principal Investigator:

Dr. Vince McGinness
Battelle Advanced Materials Center, Columbus, Ohio

      The Investigations into Polymer Membrane Processing
(IPMP), a middeck payload, will make its seventh Space Shuttle
flight for the Columbus, Ohio-based Battelle Advanced Materials
Center, a NASA Center for the Commercial Development of Space,
sponsored in part by the Office of Commercial Programs.

      The objective of IPMP is to investigate the physical and
chemical processes that occur during the formation of polymer
membranes in microgravity such that the improved knowledge base
can be applied to commercial membrane processing techniques.
Supporting the overall program objective, the STS-50 mission
will provide additional data on the polymer precipitation
process.

      Polymer membranes have been used by industry in
separation processes for many years.  Typical applications
include enriching the oxygen content of air, desalination of
water and kidney dialysis.

      Polymer membranes frequently are made using a two-step
process.  A sample mixture of polymer and solvents is applied
to a casting surface.  The first step involves the evaporation
of solvents from the mixture.  In the second step, the
remaining sample is immersed in a fluid (typically water) bath
to precipitate the membrane, form the solution and complete the
process.

      On STS-50, a crew member will activate the IPMP
experiment by sliding the stowage tray which contains two IPMP
units to the edge of the locker.  By turning each unit's valve
to an initial position, the evaporation process is initiated.
The evaporation process will last 5 minutes for one unit and 1
hour for the other.  Subsequently, the units' valves will be
turned to a second position, initiating a 15-minute
precipitation process which includes quenching the membrane
with water.  Once the precipitation process is complete, the
stowage tray will be slid back into the locker for the flight's
duration.

      Following the flight, the samples will be retrieved and
returned to Battelle for testing.  Portions of the samples will
be sent to the CCDS's industry partners for quantitative
evaluation consisting of comparisons of the membranes'
permeability and selectivity characteristics with those of
laboratory-produced membranes.


ORBITAL ACCELERATION RESEARCH EXPERIMENT (OARE)

Principal Investigator:

Robert C. Blanchard
NASA Langley Research Center, Hampton, Va.

       The Orbital Acceleration Research Experiment (OARE)
provides measurements of orbiter aerodynamic data within the
thin atmosphere of extreme altitudes.  Aerodynamic data is
acquired on-orbit and during the high-altitude portion of
atmospheric entry.  The OARE instrument comprises a three-axis
set of extremely sensitive linear accelerometers, which measure
the vehicle's response to aerodynamic forces.  These
accelerometers are capable of measuring acceleration levels as
small as one part per billion of Earth's gravity.

       Because of their extreme measurement sensitivity, the
OARE sensors cannot be adequately calibrated on the ground, in
the presence of Earth's gravity.  Consequently, the sensors are
mounted on a rotary calibration table which enables an accurate
instrument calibration to be performed on-orbit.

       The OARE instrument is installed for flight at the
bottom of the orbiter's payload bay on a special carrier plate
attached to the orbiter's keel.  OARE data are recorded both on
the mission payload recorder and within the OARE's own solid-
state memory for analysis after the flight.



Shuttle Amateur Radio Experiment


       The Shuttle Amateur Radio Experiment (SAREX) is designed
to demonstrate the feasibility of amateur shortwave radio
contacts between the Space Shuttle and ground amateur radio
operators, often called ham radio operators. SAREX also serves
as an educational opportunity for schools around the world to
learn about space first hand by speaking directly to astronauts
aboard the Shuttle via ham radio. Contacts with certain schools
are included in planning the mission.

       Ham operators may communicate with the Shuttle using VHF
FM voice transmissions, slow scan television and digital
packet. Several selected ground stations also will be able to
send standard television to the crew via SAREX. The television
uplink will be used to send video of the crew's families and of
the launch.

       The primary voice frequencies to be used during STS-50
are 145.55 MHz for transmissions from the spacecraft to the
ground and 144.95 MHz for transmissions from the ground to the
spacecraft. Digital packet and slow scan television will
operate on the same frequencies, while the television uplink
will be limited to the UHF ham band at 450 MHz.

       Equipment aboard Columbia will include a low-power,
hand-held FM transceiver, spare batteries, headset, an antenna
custom designed by NASA to fit in an orbiter window, interface
module and an equipment cabinet.


       SAREX has flown previously on Shuttle missions STS-9,
STS-51F, STS-35, STS-37 and STS-45.  SAREX is a joint effort by
NASA, the American Radio Relay League (ARRL), the Amateur Radio
Satellite Corp. and the Johnson Space Center Amateur Radio
Club. Information about orbital elements, contact times,
frequencies and crew operating times will be available from
these groups during the mission and from amateur radio clubs at
other NASA centers.

       Ham operators from the JSC club will be operating on HF
frequencies and the AARL (W1AW) will include SAREX information
in its regular HF voice and teletype bulletins.  The Goddard
Space Flight Center Amateur Radio Club, Greenbelt, Md., will
operate 24 hours a day during the mission, providing
information on SAREX and retransmitting live Shuttle air-to-
ground communications.  In addition, the NASA Public Affairs
Office at the Johnson Space Center will have a SAREX
information desk during the mission.


STS-45 SAREX Operating Frequencies

Location         Shuttle Transmission        Shuttle Reception

U.S., Africa     145.55 MHz                  144.95 MHz
South America    145.55                      144.97
and Asia         145.55                      144.91

Europe           145.55 MHz                  144.95 MHz
                 145.55                      144.75
                 145.55                      144.70

               Goddard Amateur Radio Club Operations
          (SAREX information and Shuttle audio broadcasts)

                  3.860 MHz                   7.185 MHz
                 14.295 MHz                  21.395 MHz
                 28.395 MHz

SAREX information also may be obtained from the Johnson Space
Center computer bulletin board (JSC BBS), 8 N 1 1200 baud, at
713/483-2500 and then type 62511.  The same information may be
obtained from NASA Spacelink, 8 N 1 300-9600 baud at 205/895-0028
or 128.158.13.250 via Internet.



STS-50 PRELAUNCH PROCESSING


      Columbia arrived at KSC on Feb. 9, after a 6-month
modification period at Rockwell International in Palmdale,
Calif.  Some of the major changes incorporated into the
flagship orbiter will allow for extended duration missions up
to 16 days.

       Changes made to equip the orbiter for extended flights
include adding an extended duration orbiter (EDO) pallet to
meet additional power and water requirements, increasing the
capacity of the waste collection system, installing the
regenerative carbon dioxide removal system for removing carbon
dioxide from the crew cabin atmosphere, installing two
additional nitrogen tanks for the crew cabin atmosphere and
augmenting the stowage space with extra middeck lockers.

       Other systems on board Columbia now feature design
changes or updates as part of continued improvements to the
Space Shuttle.  The upgrades include several improved or
redesigned avionics systems, the drag chute and new beefed-up
main gear tires that use a synthetic rubber tread instead of
the natural rubber previously used.

       While in the Orbiter Processing Facility (OPF), flight
technicians installed the three main engines.  Engine 2019 is
in the No. 1 position, engine 2031 is in the No. 2 position and
engine 2011 is in the No. 3 position.

       After being readied for its 12th flight, Columbia was
transferred out of the OPF on May 29th and towed several
hundred yards to the Vehicle Assembly Building (VAB) and
connected to its external tank and solid rocket boosters on the
same day.

       In the VAB technicians connected the 100-ton space plane
to its already stacked solid rocket boosters and external tank.
Columbia was scheduled to be transferred to pad 39-A the week
of June 1.

       The primary STS-50 payload, the U.S. Microgravity
Laboratory-1, was installed in the OPF on April 13.  An
interface verification test between the orbiter and laboratory
was completed.

       In addition to the routine operations at the launch pad,
a test is scheduled in which the orbiter's fuel cell storage
tanks and extended duration orbiter pallet tanks will be loaded
with liquid oxygen and liquid hydrogen reactants.  This test
will validate procedures and establish timelines to tank and
detank the EDO pallet.

       Also planned is the Terminal Countdown Demonstration
Test with the STS-50 flight crew during the week of June 8.

       A standard 43-hour launch countdown is scheduled to
begin 3 days prior to launch.  During the countdown, the
orbiter's fuel cell storage tanks and extended duration orbiter
pallet tanks will be loaded with fuel and oxidizer and all
orbiter systems will be prepared for flight.  The hold time
will be extended to allow extra time for loading the EDO pallet
with cryogenic propellants.

       About 9 hours before launch, the external tank will be
filled with its flight load of a half million gallons of liquid
oxygen and liquid hydrogen propellants.  About 2 1/2 hours
before liftoff, the flight crew will begin taking their
assigned seats in the crew cabin.

       Columbia's end-of-mission landing is planned for Edwards
Air Force Base, Calif.  Columbia's landing will feature the
drag chute.  KSC's landing and recovery teams will be on hand
to prepare the vehicle for the cross-country ferry flight back
to Florida.  Columbia's next flight, STS-52, is planned this
fall with the LAGEOS II payload.



STS-50 Crew Biographies


Richard N. Richards, 45, Capt., USN, will serve as Commander of
STS-50.  Selected as an astronaut in May 1980, Richards
considers St. Louis, Mo., his hometown and will be making his
third space flight.

       Richards graduated from Riverview Gardens High School,
St. Louis, in 1964; received a bachelor's in chemical
engineering from the University of Missouri in 1969; and
received a master's in aeronautical systems from the University
of West Florida in 1970.

       Richards first flew as pilot of Shuttle mission STS-28,
a Department of Defense-dedicated mission in August 1989.  His
next flight was as commander of STS-41, a mission that deployed
the Ulysses solar probe in October 1990.  He has logged more
than 219 hours in space.


Kenneth D. Bowersox, 36, Lt. Cmdr, USN, will serve as pilot.
Selected as an astronaut in June 1987, Bowersox considers
Bedford, Ind., to be his hometown and will be making his first
space flight.

       Bowersox graduated from Bedford High School, Bedford,
Ind.; received a bachelor's in aerospace engineering from the
Naval Academy in 1978; and received a master's in mechanical
engineering from Columbia University in 1979.

       He was designated a naval aviator in 1981 and was
assigned aboard the USS Enterprise, where he completed more
than 300 carrier landings.  In 1985, he graduated from the Air
Force Test Pilot School and was assigned as the A-7E and F/A-18
test pilot at the Naval Weapon Center when selected by NASA.
Bowersox has logged more than 2,000 hours flying time.


Bonnie J. Dunbar, 43, will serve as mission specialist 1 (MS1)
and as payload commander.  Selected as an astronaut in August
1981, she considers Sunnyside, Wash., to be her hometown and
will be making her third space flight.

       Dunbar graduated from Sunnyside High School, Sunnyside,
Wash.; received a bachelor's and a master's in ceramic
engineering from the University of Washington; and received a
doctorate in biomedical engineering from the University of
Houston.

       Dunbar first flew on STS-61A, the Spacelab D-1 mission,
in November 1985.  Her next flight was on STS-32, the mission
to retrieve the Long Duration Exposure Facility in January
1990.  She has logged 430 hours in space.


Ellen Baker, 39, will serve as mission specialist 2 (MS2).
Selected as an astronaut in May 1984, Baker considers New York,
N.Y., to be her hometown and will be making her second space
flight.

       Baker graduated from Bayside High School in New York
City; received a bachelor's degree in geology from the State
University of New York; and received a doctorate of medicine
from Cornell University.

       Baker first flew on STS-34, a mission that deployed the
Galileo probe to Jupiter in October 1989.  She joined NASA in
1981 and served as a physician in the Flight Medicine Clinic
until her selection as an astronaut.  Baker has logged more
than 119 hours in space.


Carl J. Meade, 41, Col., USAF, will serve as mission specialist
3 (MS3). Selected as an astronaut in June 1985, Meade considers
Universal City, Texas., his hometown and will be making his
second space flight.

       Meade graduated from Randolph High School, Randolph Air
Force Base, Texas.; received a bachelor's in electronics
engineering from the University of Texas; and received a
master's in electronics engineering from the California
Institute of Technology.

       Meade first flew on STS-38 in November 1990, a
Department of Defense-dedicated Shuttle mission.  He has logged
more than 117 hours in space.


Lawrence J. DeLucas, 41, will serve as payload specialist 1
(PS1).  DeLucas was born in Syracuse, N.Y., and will be making
his first space flight.

       DeLucas received a bachelor's and master's in chemistry
from the University of Alabama at Birmingham; received a
bachelor's in physiological optics from the University of
Alabama at Birmingham; and received doctorates of optometry and
biochemistry from the University of Alabama at Birmingham.

       He has served as associate director of the Center for
Macromolecular Crystallography at the University of Alabama
since 1986; has been a member of the NASA Science Advisory
Committee for Advanced Protein Crystal Growth since 1987; and
is a professor in the University of Alabama's Department of
Optometry.  He also is a member of the graduate faculty at the
University of Alabama.


Eugene H. Trinh, 41, will serve as payload specialist 2 (PS2).
Trinh is a resident of Culver City, Calif., and will be making
his first space flight. Trinh was born in Saigon, Vietnam, and
was raised in Paris, France, since age 2.  He has lived in the
United States since 1968.

       Trinh graduated from Lycee Michelet, Paris, with a
baccalaureate degree; received a bachelor's in mechanical
engineering-applied physics from Columbia University in 1972;
received a master's in applied physics from Yale University;
and received a doctorate in applied physics from Yale.

       Trinh's research work has focused on physical acoustics,
fluid dynamics and containerless materials processing.  He
served as an alternate payload specialist for NASA for the
Spacelab 3 mission in May 1985 and has developed several
Shuttle flight experiments.  He also is a member of the NASA
Space Station Freedom Experiments planning group for
Microgravity Science.



STS-50 MISSION MANAGEMENT

NASA HEADQUARTERS, Washington,  D. C.

Office of Space Flight

Jeremiah Pearson               Associate Administrator
Thomas E. Utsman               Deputy Associate Administrator
Bryan O'Connor                 Deputy Associate Administrator
                                 (Programs)
Leonard Nicholson              Director, Space Shuttle

Office of Space Science and Applications

Dr. Lennard A. Fisk            Associate Administrator
Alphonso V. Diaz               Deputy Associate Administrator
Robert C. Rhome                Director, Microgravity Science
                                 and Applications Division
Dr. Roger Crouch               USML-1 Program Scientist
Robert H. Benson               Director, Flight Systems
                                 Division
James McGuire                  USML-1 Program Manager

Office of Commercial Programs

John G. Mannix                 Assistant Administrator
Richard H. Ott                 Director, Commercial Development
                                 Division
Garland C. Misener             Chief, Flight Requirements
                                 and Accommodations


Ames Research Center, Mountain View, Calif.

Dr. Dale L. Compton            Director
Victor L. Peterson             Deputy Director
Dr. Steven A. Hawley           Associate Director
Dr. Joseph C. Sharp            Director, Space Research


AMES-DRYDEN FLIGHT RESEARCH FACILITY, EDWARDS, CALIF.

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


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
Bascom W. Murrah                Columbia Flow Director
J. Robert Lang                  Director, Vehicle Engineering
Al J. Parrish                   Director of Safety Reliability
                                  and Quality Assurance
John T. Conway                  Director, Payload Management
                                  and Operations
P. Thomas Breakfield            Director, Shuttle Payload
                                  Operations
Joanne H. Morgan                Director, Payload Project
                                  Management
Russell D. Lunnen               STS-50 Payload Processing
                                  Manager


Marshall Space Flight Center, Huntsville, Ala.

Thomas J. Lee                    Director
Dr. J. Wayne Littles             Deputy Director
Harry G. Craft                   Manager, Payload Projects
                                   Office
Charles E. Sprinkle              USML Mission Manager
Dr. Donald O. Frazier            USML Mission Scientist
Alexander A. McCool              Manager, Shuttle Projects
                                   Office
Dr. George McDonough             Director, Science and
                                   Engineering
James H Ehl                      Director, Safety and Mission
                                   Assurance
Otto Goetz                       Manager, Space Shuttle Main
                                   Engine Project
Victor Keith Henson              Manager, Redesigned Solid
                                   Rocket Motor Project
Cary H. Rutland                  Manager, Solid Rocket Booster
                                   Project
Gerald C. Ladner                 Manager, External Tank Project



JOHNSON SPACE CENTER, HOUSTON

Paul J. Weitz                     Director (Acting)
Paul J. Weitz                     Deputy Director
Daniel Germany                    Manager, Orbiter and GFE
Projects
Donald R. Puddy                   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 Estes                          Director
Gerald Smith                       Deputy Director
J. Harry Guin                      Director, Propulsion Test
                                     Operations




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