STS-68 PRESS KIT


PUBLIC AFFAIRS CONTACTS

For Information on the Space Shuttle

Ed CampionPolicy/Management
Headquarters, Wash., D.C.

James Hartsfield
Mission Operations/Astronauts
Johnson Space Center, Houston

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

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

Don Haley DFRC Landing Information
Dryden Flight Research Center,
Edwards, Calif.

For Information on NASA-Sponsored STS-68 Experiments

Brian Dunbar SRL-2
Headquarters, Wash., D.C.

Mike Braukus BRIC, CHROMEX
Headquarters, Wash., D.C.

Debra Rahn International Cooperation
Headquarters, Wash., D.C.

Charles Redmond CPCG
Headquarters, Wash., D.C.

Tammy Jones GAS Experiments
Goddard Space Flight Center,
Greenbelt, Md.

For Information on DOD-Sponsored STS-68 Experiments

Dave Hess
CREAM, MAST
Johnson Space Center, Houston

CONTENTS

GENERAL BACKGROUND
General Release. . . . . . . . . . . . . . . . . . . . . . . . .3
Media Services Information . . . . . . . . . . . . . . . . . . .6
Quick-Look Facts . . . . . . . . . . . . . . . . . . . . . . . .7
Shuttle Abort Modes. . . . . . . . . . . . . . . . . . . . . . .9
Summary Timeline . . . . . . . . . . . . . . . . . . . . . . . 10
Payload and Vehicle Weights. . . . . . . . . . . . . . . . . . 11
Orbital Events Summary . . . . . . . . . . . . . . . . . . . . 11
Crew Responsibilities. . . . . . . . . . . . . . . . . . . . . 12

CARGO BAY PAYLOADS & ACTIVITIES
Space Radar Laboratory-2 (SRL-2) . . . . . . . . . . . . . . . 13
Get Away Special (GAS) Experiments . . . . . . . . . . . . . . 27

IN-CABIN PAYLOADS
Commercial Protein Crystal Growth (CPCG) . . . . . . . . . . . 31
Biological Research in Canisters (BRIC). . . . . . . . . . . . 32
Chromosomes and Plant Cell Division in Space Experiment
(CHROMEX). . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Cosmic Radiation Effects and Activation Monitor (CREAM). . . . 33
Military Applications of Ship Tracks (MAST). . . . . . . . . . 33

STS-68 CREW BIOGRAPHIES
Michael Baker, Commander (CDR) . . . . . . . . . . . . . . . . 34
Terrence Wilcutt, Pilot (PLT). . . . . . . . . . . . . . . . . 34
Thomas Jones, Payload Commander (MS4). . . . . . . . . . . . . 34
Steven Smith, Mission Specialist 1 (MS1) . . . . . . . . . . . 35
Daniel Bursch, Mission Specialist 2 (MS2). . . . . . . . . . . 35
Jeff Wisoff, Mission Specialist 3 (MS3). . . . . . . . . . . . 36


RELEASE: 94-114


SPACE RADAR LABORATORY MAKES SECOND FLIGHT

In August 1994, scientists around the world will again be
provided a unique vantage point for studying how the Earth's
global environment is changing when Endeavour begins the STS-68
Space Shuttle mission. During the 10 day mission, the Space
Radar Laboratory (SRL) payload in Endeavour's cargo bay will make
its second flight. The SRL payload, which first flew during STS-
59 in April 1994, will again give scientists highly detailed
information that will help them distinguish between human-induced
environmental changes and other natural forms of change. NASA
will distribute the data to the international scientific
community so that this essential research is available worldwide
to assist people in making informed decisions about protecting
the environment.

Leading the STS-68 crew will be Mission Commander Michael A.
Baker, who will be making his third flight. Pilot for the
mission is Terrence W. Wilcutt, who is making his first flight.
The four mission specialists aboard Endeavour are Thomas D.
Jones, the Payload Commander, who will be making his second
flight; Steven L. Smith who will be making his first flight;
Daniel W. Bursch, who will be making his second flight; and Peter
J.K. Wisoff, who will be making his second flight.

Launch of Endeavour currently is scheduled for no earlier than
August 18, 1994, at 6:54 a.m. EDT. The planned mission duration

is 10 days, 4 hours, 40 minutes. With an on-time launch on
August 18, Endeavour's landing would take place at 11:34 a.m. EDT
on August 28 at the Kennedy Space Center's Shuttle Landing
Facility.

The SRL payload is comprised of the Spaceborne Imaging Radar-
C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR), and the
Measurement of Air Pollution from Satellite (MAPS). The German
Space Agency (DARA) and the Italian Space Agency (ASI) are
providing the X-SAR instrument.

The imaging radar of the SIR-C/X-SAR instruments has the
ability to make measurements over virtually any region at any
time, regardless of weather or sunlight conditions. The radar
waves can penetrate clouds, and under certain conditions, also
can "see" through vegetation, ice and extremely dry sand. In
many cases, radar is the only way scientists can explore
inaccessible regions of the Earth's surface.

The SIR-C/X-SAR radar data provide information about how many
of Earth's complex systems_those processes that control the
movement of land, water, air and life_work together to make this
a livable planet. The science team particularly wants to study
the amount of vegetation coverage, the extent of snow packs,
wetlands areas, geologic features such as rock types and their
distribution, volcanic activity, ocean wave heights and wind
speed. STS-68 will fly over the same sites that STS-59 observed
so that scientists will be able to study seasonal changes that
may have occurred in those areas between the missions.

An international team of 49 science investigators and three
associates will conduct the SIR-C/X-SAR experiments. Thirteen
nations are represented: Australia, Austria, Brazil, Canada,
China, the United Kingdom, France, Germany, Italy, Japan, Mexico,
Saudi Arabia and the United States.

The MAPS experiment will measure the global distribution of
carbon monoxide in the troposphere, or lower atmosphere.
Measurements of carbon monoxide, an important element in several
chemical cycles, provide scientists with indications of how well
the atmosphere can cleanse itself of "greenhouse gases,"
chemicals that can increase the atmosphere's temperature.

STS-68 will see the continuation of NASA's Get Away Special
(GAS) experiments program. The project gives a person or
organization a chance to perform experiments in space on a
Shuttle mission. Two universities, North Carolina A&T State
University and University of Alabama in Huntsville, and the
Swedish Space Corp., Soina, Sweden, will have small self-
contained payloads flying during the STS-68 mission. Other GAS
hardware in Endeavour's payload bay will carry 500,000
commemorative stamps for the U.S. Postal Service in recognition
of the 25th anniversary of the Apollo 11 Moon landing.

Other payloads aboard Endeavour include the Biological
Research in Canister (BRIC) which will fly for the first time,
and the Military Applications of Ship Tracks (MAST) which will be
making its second flight. BRIC experiments, sponsored by NASA's
Office of Life and Microgravity Sciences and Applications, are
designed to examine the effects of microgravity on a wide range
of physiological processes in higher order plants and arthropod
animals (e.g., insects, spiders, centipedes, crustaceans). MAST
is an experiment sponsored by the Office of Naval Research (ONR)
and is part of a five-year research program developed by ONR to
examine the effects of ships on the marine environment.

The Commercial Protein Crystal Growth (CPCG) experiment, the
Chromosome and Plant Cell Division in Space Experiment (CHROMEX)
and the Cosmic Radiation Effects and Activation Monitor (CREAM)
experiment also will be carried aboard Endeavour.

Shuttle Mission STS-68 will be the 7th flight of Endeavour and
the 64th flight of the Space Shuttle System.


- end -
MEDIA SERVICES INFORMATION


NASA Television Transmission

NASA Television is available through Spacenet-2, Transponder
5, located at 69 degrees west longitude with horizontal
polarization. Frequency is 3880.0 MHz, audio is 6.8 MHz.

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

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

Status Reports

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

Briefings

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


STS-68 Quick Look

Launch Date/Site: August 18, 1994/KSC Pad 39A
Launch Time: 6:54 a.m. EDT
Orbiter: Endeavour (OV-105) - 7th Flight
Orbit/Inclination: 120 nautical miles/57 degrees
Mission Duration: 10 days, 4 hours, 40 minutes
Landing Time/Date: 11:34 a.m. EDT Aug. 28, 1994
Primary Landing Site: Kennedy Space Center, Fla.
Abort Landing Sites: Return to Launch Site - KSC, Fla.
TransAtlantic Abort landing - Zaragoza,
Spain;
Moron, Spain; Ben Guerir, Morocco
Abort Once Around - White Sands Space Harbor,
N.M.

STS-68 Crew: Michael Baker, Commander (CDR)
Terrence Wilcutt, Pilot (PLT)
Thomas Jones, Payload Commander (MS4)
Steven Smith, Mission Specialist 1 (MS1)
Daniel Bursch, Mission Specialist 2 (MS2)
Jeff Wisoff, Mission Specialist 3 (MS3)

Red shift: Baker, Wilcutt, Wisoff
Blue shift: Bursch, Jones, Smith


Cargo Bay Payloads: Space Radar Laboratory-2 (SRL-2)
Get Away Special canisters (GAS cans)

Middeck Payloads: Commercial Protein Crystal Growth (CPCG)
Biological Research in Canisters (BRIC)
Cosmic Radiation Effects and Activation
Monitor (CREAM)
Military Applications of Ship Tracks (MAST)


Detailed Test Objectives/Detailed Supplementary Objectives:

DTO 251: Entry Aerodynamic Control Surfaces Test
DTO 254: Subsonic Aerodynamics Verification Objectives
DTO 301D: Ascent Structural Capability Evaluation
DTO 305D: Ascent Compartment Venting Evaluation
DTO 306D: Descent Compartment Venting Evaluation
DTO 307D: Entry Structural Capability Evaluation
DTO 312: External Tank Thermal Protection System
Performance
DTO 414: Auxiliary Power Unit Shutdown Test
DTO 521: Orbiter Drag Chute System Test
DTO 656: PGSC Single Event Upset Monitoring
DTO 664: Cabin Temperature Survey
DTO 700-8: Global Positioning System Flight Test
DTO 805: Crosswind Landing Performance
DSO 317: Shuttle Humidity Condensate Collection/Evaluation

DSO 326: Window Impact Observations
DSO 484: Assessment of Circadian Shifting in Astronauts by
Bright Light
DSO 487: Immunological Assessment of Crewmembers
DSO 491: Characterization of Microbial Transfer Among
Crewmembers During Spaceflight
DSO 603B: Orthostatic Function During Entry, Landing and
Egress
DSO 604: Visual-Vestibular Integration as a Function of
Adaptation
DSO 605: Postural Equilibrium Control During Landing/Egress
DSO 614: The Effect of Prolonged Spaceflight on Head and
Gaze Stability During Locomotion
DSO 621: In-Flight Use of Florinef to Improve Orthostatic
Intolerance Postflight
DSO 624: Pre and Postflight Measurement of
Cardiorespiratory Responses to Submaximal Exercise
DSO 626: Cardiovascular and Cerebrovascular Responses to
Standing Before and After Spaceflight
DSO 901: Documentary Television
DSO 902: Documentary Motion Picture Photography
DSO 903: Documentary Still Photography


SPACE SHUTTLE ABORT MODES

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

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

* Abort-Once-Around (AOA) -- Earlier main engine shutdown with
the capability to allow one orbit around before landing at White
Sands Space Harbor, N.M.

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

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

STS-68 contingency landing sites are the Kennedy Space Center,
White Sands, Zaragoza, Moron and Ben Guerir.

STS-68 Summary Timeline


Flight Day One
Ascent
OMS-2 burn (120 n.m. x 120 n.m.)
SRL-2 activation/operations

Blue Flight Days Two-Seven
SRL-2 operations
- SIR-C/X-SAR Radar Imaging
- MAPS Carbon Monoxide Survey

Red Flight Days Two-Seven
SRL-2 operations
- SIR-C/X-SAR Radar Imaging
- MAPS Carbon Monoxide Survey

Blue Flight Day Eight
SRL-2 operations
- SSIR-C/X-SAR Interferometry
- MAPS Carbon Monoxide Survey

Red Flight Day Eight
SRL-2 operations
- SIR-C/X-SAR Interferometry
- MAPS Carbon Monoxide Survey

Blue Flight Day Nine
SRL-2 operations
- SIR-C/X-SAR Interferometry
- MAPS Carbon Monoxide Survey

Red Flight Day Nine

Flight Control Systems Checkout
Reaction Control System Hot-Fire
SRL-2 deactivation
Cabin stow

Blue/Red Flight Day Ten
Deorbit
Entry
Landing
STS-68 VEHICLE AND PAYLOAD WEIGHTS

Vehicle/Payload Pounds

Orbiter (Endeavour) empty and 3 SSMEs 173,669

Space Radar Lab-2 23,796

Get-Away Special Experiments 1,464

Biological Research in Canisters 20

Commercial Protein Crystal Growth 58

Chromosome and Plant Cell Division in Space 64

Cosmic Radiation Effects and Activation Monitor 39

Detailed Supplementary/Test Objectives 156

Total Vehicle at SRB Ignition 4,511,195

Orbiter Landing Weight 223,040



STS-68 Orbital Events Summary

EVENT START TIME VELOCITY CHANGE ORBIT
(dd/hh:mm:ss) (feet per second) (n.m.)

OMS-2 00/00:33:00 164 fps 120 x 120

Deorbit 10/02:59:00 228 fps N/A

Touchdown 10/03:59:00 N/A N/A



STS-68 CREW RESPONSIBILITIES

TASK/PAYLOAD PRIMARY BACKUPS/OTHERS

Shift CDR Baker (red) Bursch (blue)

Payload CDR Jones
SRL-2 Wisoff (red) Jones (blue)
GAS Cans Baker (red) Smith (blue)

Secondary Payloads:

CPCG Smith Wilcutt
CHROMEX Smith Wilcutt
CREAM Wilcutt Bursch
BRIC Baker Wilcutt
MAST Bursch Baker

Detailed Supplementary/Test Objectives:

Medical DSOs Bursch Baker
DTO 251 Wilcutt Baker
DTO 312 Jones Smith
DTO 326 Wilcutt Baker
DTO 414 Wilcutt Bursch
DTO 521 Baker Wilcutt
DTO 656 Wisoff Jones
DTO 664 Smith Wisoff
DTO 700-8 Bursch Jones
DTO 805 Baker Wilcutt

Other:

Photography/TV Wisoff Smith
In-Flight Maintenance Wisoff Smith
EVA Wisoff (EV1) Smith (EV2), Wilcutt (IV)

Earth Observations Wisoff Wilcutt
Geography Smith Wilcutt
Oceanography Bursch Baker
Meteorology Smith Bursch
Medical Bursch Baker

SPACE RADAR LABORATORY-2 (SRL-2)

SIR-C/X-SAR

Mission Objectives

As part of NASA's Mission to Planet Earth, SIR-C/X-SAR is
studying how our global environment is changing. From the unique
vantage point of space, the radar system will observe, monitor
and assess large-scale environmental processes. The spaceborne
data, complemented by aircraft and ground studies, will give
scientists highly detailed information that will help them
distinguish natural environmental changes from those that are the
result of human activity. NASA will distribute the Mission to
Planet Earth data to the international scientific community so
that this essential research is available worldwide to people who
are trying to make informed decisions about protecting the
environment.

SIR-C/X-SAR is also a part of the continuing efforts by DARA,
the German Space Agency, and ASI, the Italian Space Agency, in
the field of Earth observations.

Why Radar?

The unique feature of imaging radar is its ability to collect
data over virtually any region at any time, regardless of weather
or sunlight conditions. Some radar waves can penetrate clouds,
and under certain conditions, can also see through vegetation,
dry snow and extremely dry sand. In many cases, radar is the
only way scientists can explore inaccessible regions of Earth's
surface.

Radar is a lowercase acronym for "radio detection and
ranging." A synthetic aperture radar transmits pulses of
microwave energy toward Earth and measures the strength and time-
delay of the energy that is scattered back to the antenna. In
the case of SIR-C/X-SAR, the motion of the Shuttle creates, or
synthesizes, an antenna opening, or aperture, that is much longer
than the actual antenna hardware. A longer antenna produces
images of finer resolution.

Conditions on the Earth's surface influence how much radar
energy is reflected back to the antenna. An area with a variety
of surface types, such as hills, trees and large rocks, will
generally reflect more energy back to the radar than a less
complex area such as a desert. The resulting radar image of the
varied terrain will be brighter overall and have higher contrasts
than the image of the simpler area. The three frequencies of
SIR-C/X-SAR will enable scientists to view three different scales
of features in the images.

Results of STS-59

Flying aboard STS-59 in April 1994, SIR-C collected 65 hours
of data during the 10-day mission, roughly corresponding to 26
million square miles (66 million square kilometers). All data
were stored onboard the Shuttle using a new generation of high
density, digital, rotary head tape recorders. The data filled
166 digital tape cartridges (similar to VCR tape cassettes). X-
SAR data filled 25 of those tapes.

The mission returned 47 terabits of data (47 x 1012 bits).
Stated another way, each of the radars generates 45 million bits
of data per second. When all the radars are operating, they
produce 225 million bits of data per second, the equivalent of 45
simultaneously operating television stations. Using JPL's
digital SAR processor and German-Italian X-SAR processors, the
ground team processed the raw data into images.

High-priority SIR-C data were downlinked, processed, and
released to the science team via the Internet within 24 hours of
collection. The payload operations team processed the SIR-C data
in survey mode and displayed it during the mission on NASA
Television.

Science

The STS-59 mission achieved 100 percent of the SIR-C/X-SAR
science objectives. The SRL-1 team completed 850 data takes, 97%
of those planned. The team acquired 99% of the "supersite"
opportunities over highest priority targets. The 94 hours of
radar imagery were obtained over 44 countries, covering 43.75
million square miles (70 million square kilometers). In addition
to taking high-resolution data at all of the planned sites, the
science team was able to adjust the mission timeline and observe
events as they were happening on the ground. SIR-C/X-SAR took
data of the severe flooding that inundated the mid-western United
States and Thringen, Germany, as well as three different views
of tropical Cyclone Odille as it formed in the Pacific Ocean.
Scientists also acquired a series of radar images over Canada
documenting the annual spring thaw of snow, ice and soil.

Scientists use SIR-C/X-SAR data to study how our global
environment is changing. The SIR-C/X-SAR radar data provides
information about how many of Earth's complex systems_those
processes that control the movement of land, water, air and
life_work together to make this a livable planet. The science
team particularly wants to study the amount of vegetation
coverage, the extent of snow packs, wetlands areas, geologic
features such as rock types and their distribution, volcanic
activity, ocean wave heights and wind speed. STS-68 will fly
over the same sites that STS-59 observed so that scientists will
be able to study seasonal changes that may have occurred in those
areas between the missions.
Data will be taken over more than 400 sites on Earth.
Nineteen of the sites are "supersites," the highest priority
targets and the focal point for many of the scientific
investigators. There are 15 backup supersites. If problems
should occur during the flight that would drastically reduce the
team's ability to collect data, the supersite data will take
precedence over other data acquisition.

During STS-59 the scientists who were working in the Payload
Operations Control Center in Houston were in daily communication
with the researchers who were part of the "ground truth" teams.
The ground teams at several of the supersites made simultaneous
measurements of vegetation, soil moisture, sea state, snow and
weather during the mission. Aircraft and ships also collected
data to ensure an accurate interpretation of the radar data taken
from space. In addition, the astronauts recorded their personal
observations of weather and environmental conditions in
coordination with SIR-C/X-SAR operations.

Supersites

The supersites represent different environments within each
scientific discipline. They are areas where intensive field work
will occur before, during and after the flight.

Ecology

Supersites: Manaus, Brazil; Raco, Mich.; Duke Forest, N.C.

Ecologists study life on Earth and how different species of
animals and plants interact with one another and their local
environment. SIR-C/X-SAR ecology investigations focus on mapping
wetlands, deforestation and flooding under forest canopies over
the tropical forests of the Amazon basin in South America and
over the temperate forests of North America and Central Europe.
Scientists also are studying wetlands and are using the data to
validate computer models to determine the type and density of
vegetation and to study seasonal thaws. The science team will
use the images to study land use, including the volume, types and
extent of vegetation and the effects of fires, floods and clear-
cutting.

Using early-release data, science team members have already
generated both tree classification and vegetation biomass maps of
the Raco, Michigan site and a freeze/thaw map over the Prince
Albert, Saskatchewan backup supersite. A map of flooding near
Manaus, Brazil also has been produced as a step toward improving
models and our understanding of flooding and wetlands under dense
forest canopies.

SIR-C/X-SAR's three radar frequencies interact with the
vegetation in different ways, providing views of different parts
of the forest. The shortest wavelength (X-band), reflects from
the leaves of trees. C-band microwaves reflect from twigs and
branches, and L-band wavelengths reflect from the trunks of
trees. These data give scientists a clearer picture of the
conditions on the ground.

The science team will study seasonal changes in the forest by
comparing data from the two SIR-C/X-SAR flights. For example,
data from two previous imaging radar missions showed a decrease
in forests along the Mississippi River between 1978 and 1981.
Deforestation threatens both temperate and tropical forests
around the world. SIR-C/X-SAR data and ground data will be used
to understand the impact of the loss of forests on local
populations of plants and animals. By studying the short-term
and long-term changes in forests, scientists can determine what
effects changing environmental conditions and land uses have on
the forests and, in turn, on global climate change.

Hydrology

Supersites: Chickasha, Oklahoma; Otztal, Austria; Bebedouro,
Brazil; Montespertoli, Italy

SIR-C/X-SAR hydrology investigations are focused on Brazil,
Austria, Italy and Oklahoma, where the radar data will be used to
determine soil moisture patterns. These studies will help
scientists develop ways to estimate soil moisture and evaporation
rates over large areas, which could ultimately be incorporated
into computer models to help predict a region's water cycle.

Another significant part of hydrology centers on snow cover.
Using data from STS-59, investigators generated a snow and ice
classification map over the Oetztal, Austria, supersite and a
snow-wetness map of the Mammoth Mountain, Calif., backup
supersite. Spring snow melt often determines the annual runoff
cycle and the resulting water supply, ground water and reservoir
replenishment rates. For many areas, long-term or ground-based
snow cover data do not exist, and radar data is the only
efficient way to collect this information.

SIR-C/X-SAR acquired snow cover data over Mammoth Lakes,
Calif., the Austrian Alps and northwest China. The shorter
wavelength X-band data are useful in determining snow type, while
the longer wavelengths of L-band and C-band help estimate snow
thickness. These data might help communities determine how much
water will be available for human and agriculture use. In
August, this investigation's emphasis will shift to the
Patagonian district in southern Chile, which contains the largest
glaciers and ice fields in South America.

Oceanography

Supersites: The Gulf Stream (mid-Atlantic region); eastern
North Atlantic Ocean; Southern Ocean

Oceanographers study how waves move through the ocean and how
the air and sea interact. The ocean is a reservoir for heat and
energy, and the air-sea interaction moves this heat and energy
around the globe regulating the Earth's climate. The Gulf Stream
off the eastern coast of North America is a major ocean current
that transports heat from the equator toward the poles.

The relatively low altitude of the Shuttle is particularly
advantageous for oceanography investigations since the SIR-C/X-
SAR radars are more sensitive to ocean features than satellites
in higher orbits. Oceanographers are using data from SIR-C/X-SAR
to study surface and internal waves and the interactions of waves
and current. In addition, an associated experiment provided by
the Applied Physics Laboratory of the Johns Hopkins University,
Baltimore, Md., collected extensive information on wave energy
over the Southern Ocean. These data will help scientists study
how the ocean moderates Earth's climate.

Geology

Supersites: Galapagos Islands; Sahara Desert; Death Valley,
Calif.; Andes Mountains, Chile

Geologists study the present surface of the Earth. By
observing older rocks they can determine how an area came to be
and what it may have looked like in the past. Scientists are
using SIR-C/X-SAR data to map geologic structures and variations
in rock types over large areas, as well as areas of volcanic
activity and erosion.

The longer L-band radar wavelength is particularly useful for
looking beneath surfaces. SIR-C/X-SAR obtained penetration data
of the Sahara desert that show stream channels and a larger river
valley beneath an extensive sand sheet. On the ground and in
photographs, this big valley and the channels in it are entirely
covered by windblown sand. SIR-A observed some of these channels
in 1981. Scientists hypothesize that an ancient westward-flowing
river carved the large valley, tens of millions of years before
the Nile River existed. The Nile flows north about 200 miles
(300 kilometers) east of the area observed by the radar.

The existence of hidden river channels indicates that portions
of the Sahara have undergone significant climate change and have
evolved from an area of flowing streams to what is now an arid
desert. SIR-C/X-SAR also is studying other geologic features
that record past climate changes.

In areas of Death Valley, Calif., western China and the
Patagonia region of the southern Andes, the radar imaged alluvial
fans. Alluvial fans are gravel deposits that erode and wash down
from the mountains. They are found throughout the semi-arid
deserts of the world in areas where there is a significant amount
of tectonic activity and erosion. The gravel builds up at the
base of the mountains during periods of overall wetter climate.
The radar is sensitive to these rocky and rough surfaces,
allowing scientists to study an area's climatic and geologic
history and the relative age of surfaces. As an area ages, it is
exposed to weathering. This changes its roughness
characteristics. Studying past climate changes will give
scientists a base from which to monitor and predict future
climate changes.

During STS-59, SIR-C/X-SAR acquired radar images of several
volcanoes, including Mount Pinatubo in the Philippines and the
volcanoes of the Galapagos Islands. These radar images are
helping scientists identify the different types of lava flows and
their ages and assess environmental risks posed by the volcanoes.
A key objective of STS-68 will be to obtain a second image of
Mount Pinatubo during the summer monsoon season, when new
mudflows are likely to occur, and to evaluate whatever short-term
changes may have taken place.

Calibration

Supersites: Flevoland, The Netherlands; Kerang, Australia;
Oberpfaffenhofen, Germany; Western Pacific Ocean

The ground teams placed calibration devices, called corner
reflectors, and transponders in southern Germany, the
Netherlands, Australia and Death Valley, Calif., to measure the
amount of radar energy obtained on the ground during the flight.
The teams are calibrating the radar data and applying what they
learn to the image processing and scientific interpretation of
the images.

Rain Experiment

Two SIR-C/X-SAR experiments imaged rain over the Western
Pacific Ocean, an area scientists call the "rainiest place on
Earth." Rain can change conditions on the surface and thus
change the radar image. At the shorter wavelengths of X-band and
C-band, rain may reduce the strength of the radar or scatter the
signals significantly.

The rain experiments offer a unique challenge to the operation
of the radar during flight. All the other experiments can be
reasonably tied to a specific area, while the rain experiments
only require that a "deep" rainstorm be in progress. Weather

targets are transitory in both space and time and cannot be
scheduled, so finding a good target of opportunity is a gamble.
Scientists chose the western Pacific because there is a high
probability that it will be raining there when the Shuttle passes
over it.

Interferometry: A new SIR-C/X-SAR Experiment

One of the bonuses of flying SIR-C/X-SAR for a second time is
the opportunity to demonstrate a different data-gathering method
from the Shuttle platform, called interferometry. Scientists
will conduct the experiment during the last three days of the
flight using repeated passes of SIR-C/X-SAR over the same areas
on the Earth. By comparing data from two repeated passes,
investigators hope to generate digital elevation models
(topography) of the Earth's surface. Once topography is
determined, a third interferometric pass can be used to determine
what, if any, topographic change has occurred in the intervening
time between radar passes.

The focus of these experiments is to improve our understanding
of natural hazards such as flooding, subsidence, mudflows,
earthquakes and volcanic eruptions. For example, the topography
of mountain glaciers is important because it directly reflects
ice-flow dynamics and is closely linked to global climate and sea
level change. Monitoring mountain glaciers on a global, long-
term basis could give scientists important information on the
rate of global warming. In addition, the use of topographic data
may help reduce the risk of natural disasters by monitoring
volcanoes, flooding and earthquake-prone faults.

Spaceborne Imaging Radar C/X-Band Synthetic Aperture Radar
(SIR-C/X-SAR)

SIR-C/X-SAR is a sophisticated set of radars that fills nearly
all of Endeavour's cargo bay. SIR-C, built by the Jet Propulsion
Laboratory (JPL) Pasadena, Calif., and the Ball Communications
Systems Division, is a two-frequency radar including L-band (9-
inch, or 23-cm, wavelength) and C-band (2.4-inch, or 6-cm
wavelength). SIR-C is the first spaceborne radar with the
ability to transmit and receive horizontally and vertically
polarized waves at both frequencies. The multi-frequency, multi-
polarization capability creates a new and more powerful tool for
studying the world. A good way to understand this is to think of
visual images: Just as color pictures have more information
about a subject than black and white pictures, multi-frequency,
multi-polarization radar images contain more information about
the surface than single frequency, single polarization radar
images.

The SIR-C antenna is the most massive piece of flight hardware
ever built at JPL. Its mass is 16,100 pounds (7,300 kg) and it
measures 39.4 feet by 13.1 feet (12 meters by 4 meters). The
instrument comprises several subsystems: the antenna array, the
transmitter, the receivers, the data-handling subsystem and the
ground processor. The antenna consists of three leaves, and each
is divided into four subpanels.

Hundreds of small transmitters embedded in the surface of the
antenna form the radar beam. By adjusting the energy from these
transmitters, the payload operations team can point the beam
electronically, without moving the antenna. This feature,
combined with the roll and yaw maneuvers of the Shuttle, will
allow the team to acquire images from 15-to 55- degree angles of
incidence.
Advances in radar technology will allow SIR-C to acquire
simultaneous images at L-band and C-band frequencies at multiple
polarizations. Polarization describes how the radar wave travels
in space. For example, for HH-polarized data, the antenna
transmits energy in the horizontal plane and receives the
backscattered radiation in the horizontal plane. For HV
polarization, the wave is transmitted horizontally, but is
received in the vertical plane. The interaction between the
transmitted waves and the Earth's surface determines the
polarization of the waves received by the antenna.

Multi-polarization data contain more specific information
about surface conditions than single polarization data. Multi-
polarization data are particularly useful to scientists studying
vegetation because the data allow them to see different types of
crops and to measure the volume of trees contained under the
canopy of a forest. SIR-C can acquire data with HH, VV, HV, and
VH polarizations.

X-SAR was built by the Dornier and Alenia Spazio companies for
the German Space Agency, Deutsche Agentur fuer
Raumfahrtangelegenheiten (DARA), and the Italian Space Agency,
Agenzia Spaziale Italiana (ASI), with the Deutsche
Forschungsanstalt fr Luft- und Raumfarht (DLR) as a major
partner. It is a single-polarization radar operating at X-band
(1-inch, or 3-centimeter wavelength).

X-SAR uses a finely tuned slotted waveguide antenna to produce
a pencil-thin beam of energy. The X-SAR antenna rests on a
supporting structure that is tilted mechanically to align the X-
band beam with the L-band and C-band beams. X-SAR will provide
VV polarization images.

The payload team can operate SIR-C and X-SAR independently or
together. When combined into a three-frequency, multi-
polarization instrument, SIR-C/X-SAR becomes the most powerful
civilian radar ever flown in space. The width of the ground
swath varies from 9 to 56 miles (15 to 90 kilometers), depending
on the orientation of the antenna beams. The resolution of the
radars varies from 33 to 656 feet (10 to 200 meters).

Previous Radar Missions

Since the late 1970s a variety of NASA satellite missions have
used imaging radar to study Earth and our planetary neighbors.
Perhaps the most familiar example of NASA's success using imaging
radar is the Magellan mission to Venus. Magellan's radar pierced
the dense clouds covering Venus to map the entire surface of the
planet, revealing a world hidden to humans until the late 20th
century.

SIR-C is the latest in a series of Earth observing imaging
radar missions that began in June 1978 with the launch of Seasat
SAR and continued with SIR-A in November 1981 and with SIR-B in
October 1984. Both the SIR-A and SIR-B sensors built upon the
Seasat SAR, and all three could transmit and receive horizontally
polarized radiation at L-band frequency.

The major difference between the Seasat and SIR-A sensors was
the orientation of the radar's antenna with respect to Earth's
surface. Microwave radiation transmitted by Seasat struck the
surface at a fixed angle of approximately 23 degrees from the
local zenith direction. SIR-A viewed the surface at a fixed 40-
degree angle.

SIR-B improved upon both those missions because its antenna
could be mechanically tilted. This allowed SIR-B to obtain
multiple radar images of a given target at different angles
during successive Shuttle orbits.

The X-SAR antenna is a follow-on to Germany's Microwave Remote
Sensing Experiment (MRSE), which flew aboard the first Shuttle
Spacelab mission in 1983.

These early missions had a tremendous impact on the
international remote sensing community when SIR-A discovered
ancient river beds hidden beneath the sands of the Sahara, and
SIR-B data led explorers to the Lost City of Ubar in Oman.

Data Acquisition Plans for STS-68

Portions of the SIR-C/X-SAR data will be downlinked to the
ground in near-real time through NASA's Tracking and Data Relay
Satellite System (TDRSS). However, only one channel of data can
be downlinked or played back at a time. This is not a problem
for X-SAR since it only has one channel of data. SIR-C has up to
four channels of data, and each channel must be played back
separately. The payload teams will process the data in images
using digital SAR processors in Pasadena, Calif.,
Oberpfaffenhofen, Germany, and Matera, Italy.

Historically, processing SAR data has required a great deal of
computer time on special-purpose computer systems. SIR-C/X-SAR
scientists will benefit, however, from rapid advances in computer
technology that make it possible to process the images with a
standard parallel supercomputer. Yet even with these advances,
it will still take five months to produce survey images from the
large volume of data acquired. Detailed processing will take
another nine months. Italy, Germany and the United States will
exchange data to meet the needs of the science investigators.

NASA, DARA and ASI will attempt to release some radar images
to the press during the Shuttle flight. JPL will process SIR-C
images and send them over the Internet to the Johnson Space
Center, where the image will be released on NASA Television. JPL
also will release hard-copy prints simultaneously to the wire
services. In Germany, DLR will process X-SAR imagery. In
addition, X-SAR "quick look" data will be available for release
over NASA Television.

Science Team

An international team of 49 science investigators and three
associates will conduct the SIR-C/X-SAR experiments, representing
13 nations: Australia, Austria, Brazil, Canada, China, England,
France, Germany, Italy, Japan, Mexico, Saudi Arabia and the
United States.

Dr. Diane Evans of JPL is the U.S. project scientist. Dr.
Herwig Ottl of DLR is the German project scientist and Prof.
Mario Calamia of the University of Florence is the Italian
project scientist. Dr. Miriam Baltuck of NASA's Office of
Mission to Planet Earth is the program scientist.

Management

JPL manages the SIR-C mission for NASA's Office of Mission to
Planet Earth, Washington, D.C. Michael Sander is the JPL project
manager. X-SAR is managed by the Joint Project Office (JPO)
located near Bonn, Germany. Rolf Werninghaus of DARA is the
project manager and Dr. Paolo Ammendola of ASI is the deputy
project manager. James McGuire of the Office of Life and
Microgravity Sciences and Applications, Washington, D.C., is the
SRL program manager. Richard Monson of the Office of Mission to
Planet Earth is the SIR-C program manager.

MEASUREMENT OF AIR POLLUTION FROM SATELLITES (MAPS)

The MAPS experiment measures the global distribution of carbon
monoxide_an important indicator of the atmosphere's ability to
cleanse itself of greenhouse gases and pollutants_in the lower
atmosphere (2 to 10 miles above the surface). Covering the Earth
between 57 degrees North latitude and 57 degrees South latitude,
the MAPS measurements provide the only near-global database of
lower-atmosphere carbon monoxide values available to scientists.

Preliminary results from the April 1994 MAPS flight aboard
STS-59 showed low carbon monoxide concentrations in the Southern
Hemisphere (very clean air) with a gradual increase, moving
northward, in carbon monoxide levels. The highest levels of
carbon monoxide were present north of the 40 degree latitude band
in the Northern Hemisphere. The MAPS measurements will be
correlated with ground- and aircraft-based carbon monoxide
measurements, astronaut observations and photography, and
meteorological data analyses and satellite images.

MAPS' unique measurements of carbon monoxide, a gas produced
by the burning of gasoline and other carbon-based fuels, provide
scientists with indications of how well the atmosphere can
cleanse itself of these pollutants. How far pollutants such as
carbon monoxide are transported from their source regions and the
size of the source regions are two other invaluable pieces of
information provided by the MAPS measurements.

Because MAPS is being flown twice this year, scientists will
be able to examine seasonal differences in the distribution of
carbon monoxide. This will be especially valuable to scientists
studying the transportation of industrial pollutants in the
Northern Hemisphere and biomass burning in the tropics and
Southern Hemisphere.

The STS-68 flight will occur during the Southern Hemisphere's
dry season (June-October), when the maximum amount of biomass
burning, such as clearing forests for agriculture uses, occurs.
The dry season carbon monoxide levels from this flight will be
compared to data from the wet season (April 1994) flight. The
MAPS measurements also will be compared to data from previous
dry-season MAPS flights (November 1981 and October 1984).

Why do we measure carbon monoxide?

World-wide increases in human technological and agricultural
activity are causing increasing amounts of carbon monoxide to be
released into the atmosphere. Carbon monoxide, a colorless and
odorless gas, is produced by the burning of carbon-based fuels
and by the burning of forests and grasslands.

Once released into the atmosphere, carbon monoxide can be
transported over long distances, eventually converting to carbon
dioxide by reacting with a chemical called the hydroxyl radical
(chemical symbol: OH). The OH radical is a key participant in
the destruction and removal of greenhouse gases such as methane.
Methane also is important in the chemical cycle of stratospheric
ozone.

As the amount of carbon monoxide in the atmosphere increases,
its reactions with the OH radical increase accordingly. These
reactions may leave less OH available to break down and remove
greenhouse gases, chemicals that can trap heat near the Earth's
surface, increasing atmospheric temperatures. Therefore,
increases in carbon monoxide levels may cause subsequent
decreases in OH levels, which can have long-term consequences on
stratospheric ozone and the levels of various greenhouse gases,
potentially influencing the Earth's climate.

Data Collection and Processing

The primary goal of the MAPS experiment is to measure the
distribution of carbon monoxide in the atmosphere between the
altitudes of 2 to 10 miles (4 to 15 kilometers). The MAPS
measurements will be stored on a tape recorder aboard the
instrument and also will be transmitted to the ground in real-
time through the Space Shuttle telemetry system. The real-time
data transmissions will be processed at the Payload Operations
Control Center to produce "quick look" maps of the measured
carbon monoxide distribution. The "quick look" maps, along with
real-time observations by the astronaut crew, will be used to
determine areas of special interest, such as large areas of
biomass burning.

An infrared camera attached to the MAPS instrument will take
pictures of each region of the Earth being measured during the
first half of the flight. The astronaut crew also will keep watch
for any signs of industrial pollution (smoke stacks, gas flares
from oil fields, etc.) and for smoke and fires caused by biomass
burning. Real-time observations by the astronaut crew and the
analysis of astronaut and MAPS instrument photographs, will play
a crucial role in understanding the measurements from the MAPS
experiment.

Following the flight, the data recorded aboard the instrument
and the data transmitted to the ground in real-time will be
merged, then processed using more sophisticated techniques than
the preliminary ("quick look") MAPS data. In addition, the MAPS
measurements will be correlated with a global network of
intercalibrated ground- and aircraft-based measurements. To
ensure the accuracy of the ground and aircraft measurements, all
the ground sites will be using the same four gas cylinders to
calibrate their instruments. This ensures that all the ground
sites have the same calibration standard (that they are
'intercalibrated') and allows for the intercomparison of carbon
monoxide data measured by dozens of different instruments around
the world.

The 25 ground sites include locations in the United States,
South Africa, Russia, Germany, Bermuda, Ireland, Hong Kong,
Australia, and New Zealand. The aircraft underflights of the MAPS
instrument include the NASA DC-8, and aircraft from INPE, Brazil;
CSIRO, Australia; the University of Maryland; and the National
Oceanic and Atmospheric Administration in Boulder, Colo.

Results From Previous Flights

MAPS, the first Space Shuttle science payload, has flown three
times: in November 1981 (STS-2), October 1984 (STS-41G) and
April 1994 (STS-59). The 1981 flight proved surprising because
the greatest concentrations of tropospheric carbon monoxide were
found in the Earth's tropical regions rather than in the
industrialized Northern Hemisphere as had been expected. The
1981 flight also showed that carbon monoxide concentrations vary
greatly from region to region.

The October 1984 flight confirmed the November 1981 finding
that the burning of forests in South America and grasslands in
Africa is a significant source of global tropospheric carbon
monoxide during the Southern Hemisphere spring (dry season).

Preliminary results from the April 1994 flight show low carbon
monoxide concentrations in the Southern Hemisphere (very clean
air) and a gradual increase in carbon monoxide levels from the
Southern Hemisphere to the Northern Hemisphere. The highest
levels of carbon monoxide measured by MAPS were present north of
the 40 degree latitude band in the Northern Hemisphere.

Because the second 1994 flight of MAPS occurs during the
burning season in South America and Africa, scientists will be
able to study the source regions of carbon monoxide as well as
its transport from the source regions. Real-time data analysis
by the MAPS operations team and observations by the astronaut
crew will help the scientists on the ground evaluate the data and
determine those regions where more detailed measurements should
be made by the MAPS instrument.

Because there will be two flights in the same year, scientists
also will be able to study the changes in carbon monoxide
distributions from the Southern Hemisphere wet season (April) to
the dry season (August), when biomass burning is at a maximum.

Scientists also will be able to examine the seasonal effects
near and downwind from the industrial source regions of the
Northern Hemisphere. This ability to study global seasonal
differences in tropospheric carbon monoxide levels is available
only through the unique measurements provided by the MAPS
instrument.

Mission Information

Information on the MAPS experiment for both the SRL-1 and SRL-
2 flights is available through Internet 24 hours a day. The
information is available via DOS, MAC, and UNIX platforms. This
information will be updated weekly prior to the SRL-2 launch with
updates during the mission as time allows.

The information can be accessed through NCSA Mosaic (an
Internet information browser and World Wide Web client). For
information on obtaining Mosaic software or help using it please
send electronic mail to:

[email protected]

For those who already have Mosaic, to access the Mosaic MAPS
home page directly, click on the File button in the header at the
top of the Mosaic home page; click on Open; type in URL to open:
http://stormy.larc.nasa.gov/press.html; click on Open.

For more information on the MAPS home page please contact:

Scott Nolf: [email protected]

The MAPS Instrument

The MAPS flight hardware consists of an optical box, an
electronics box, a tape recorder and a camera, all mounted to a
single baseplate. This assembly is mounted to a Multi-Purpose
Experiment Support Structure near the forward end of the cargo
bay. The instrument is about 36 inches long, 30 inches wide, and
23 inches high. It weighs 203 pounds and consumes about 125
watts of electrical power.

The Program Manager is Louis Caudill, and Dr. Robert J. McNeal
is the Program Scientist, both at NASA Headquarters,
Washington,D.C. The MAPS Principal Investigator is Dr. Henry G.
Reichle, Jr., and the Project Manager is John Fedors, both at
NASA Langley Research Center in Hampton, Va.



GET AWAY SPECIALS

Two universities and a foreign country have small self- contained
payloads flying on this mission. These customers are taking advantage of
NASA's unique Get Away Special (GAS) program. GAS, managed by the Goddard
Space Flight Center (GSFC), Greenbelt, Md., provides an opportunity for anyone
in the world to access space.

The GAS program presents an excellent educational tool for students.
Individuals and organizations are able to send scientific research and
development experiments into space aboard the Space Shuttle. So far, more than
a hundred GAS payloads have flown on the Shuttle. Customers flying payloads on
this mission include: G-316, North Carolina A&T University; G-503, University
of Alabama in Huntsville; G- 541, Swedish Space Corp. Following is a brief
description of each.

G-316
Customer: North Carolina A&T State University,
Greensboro, NC
Customer: Dr. Stuart Ahrens
NASA Technical Manager: Charlie Knapp

This payload contains two experiments designed to take advantage of the
microgravity environment of the orbiting Shuttle. The first is a biology
experiment that will study the effects of microgravity on the survival, mating
and development of the milkweed bug. The second is a chemistry experiment that
will use the microgravity environment to improve the growth quality and size of
a crystal of rochelle salt.

The entire payload weighs 100 pounds (45.36 kilograms) and fits in an
airtight cylindrical canister which is mounted out in the payload bay of the
orbiter. The payload is entirely self-contained and automated except for two
relays that are controlled from the orbiter by the crew. Approximately half of
the payload weight is due to batteries needed to control the experiments and
keep the payload warm.

The payload was conceived, designed and fabricated entirely by students
in the university's Student Space Shuttle Program (SSSP). The SSSP owes its
beginning to the late North Carolina A&T graduate and astronaut, Dr. Ronald E.
McNair. More than 100 students representing 12 different majors have
participated in the SSSP. The SSSP has received support in excess of $500,000
from more than 25 outside organizations, including Fortune 500 corporations.
This support has been in the form of funds, consultation and payload parts.

In addition to the primary goal of conceiving, designing and
fabricating the payload, the SSSP has a number of secondary goals that are very
important. These secondary goals are: to enhance the classroom experience by
placing students in a real world project; to develop in students a strong sense
of professionalism about their work; to have students interface with the high
technology of the Space Shuttle; and to motivate students to pursue Dr.
McNair's dream.

When G-316 is launched aboard Endeavour in August, a number of tributes
to Dr. McNair also will be on board. Attached to the outside of the payload's
canister will be a large emblem in the university's colors. Included in the
emblem will be the university's name and mascot and the inscription "Dr. Ron
McNair, 1950-1986." Also in the orbiter's cabin will be two special 8x10 color
photos, one of the Challenger crew and one of Dr. McNair.

G-503
Customer: University of Alabama in Huntsville,
Huntsville, Ala.
Customer: Candance Townley
NASA Technical Manager: Charlie Knapp

This payload is sponsored by the Students for the Exploration and
Development of Space at the University of Alabama in Huntsville to promote
hands-on experience for its members.

The primary objective of this payload is to successfully complete the
following experiment: diatom (microscopic algae) growth and survivability in a
cosmic radiation and microgravity environment; the mixing and curing of
concrete; a study of microgravity influenced root growth; and a study of
corrosive pitting in stainless steel. The secondary objective of these
experiments is to provide students with a hands-on education of what is
necessary to conduct scientific research in the space environment (funding,
design, paperwork, manufacturing, testing, etc.).

Experiment #1: The Microgravity and Cosmic Radiation Effects on Diatoms
(MCRED) is the first test of a concept for a bioregenerative (ability for
organisms to regenerate) life support system to be used on space station and
Lunar/Mars expeditions. The experiment is designed to grow a series of diatom
cultures in an ambient environment in low-Earth orbit. The microgravity and
cosmic radiation effects will be evaluated based on recorded cell populations.
The data will generate growth curves for study and interpretation. An
additional study of physical changes in the cell wall structure (silicon
dioxide) will be performed that will provide information about changes in cell
metabolism. The results will be compared against ground experiments operating
simultaneously to determine the cause of any observed changes.

Experiment #2: The Concrete Curing In Microgravity (ConCIM) experiment
is designed to give scientists and engineers valuable data about the
feasibility of mixing and curing concrete in a microgravity environment. This
data would be extremely valuable for future moon base applications. The
concrete, cured for at least seven days in microgravity, will develop most of
its ultimate chemical and physical properties. Once the experiment has been
recovered, testing and material analysis will be performed to determine the
chemical composition, the pore structure and strength of the space concrete.
Test results will be compared to data obtained from a ground-based control
sample of concrete, mixed and cured under similar conditions to determine the
effect of the gravitational differences.

Experiment #3: The Root Growth In Space (RGIS) experiment will study
effects of microgravity on the early stages of germination of several seed
types. The specific effects to be examined include production of gases during
germination and the development and distribution of chemicals and hormones as
they are affected by gravity.

Experiment #4: The Microgravity Corrosion Experiment (COMET) is
designed to examine the effects of microgravity on the mutation and growth of
pitting in metals. Pitting is an extremely localized corrosion phenomenon
which initiates on exposed surfaces and results in holes in the metal. It is
one of the most destructive and insidious forms of corrosion and usually occurs
in metal systems that exhibit a passive layer. Its effects are particularly
vicious because it is a localized and intense form of corrosion, and failures
often occur with extreme suddenness. Also, unlike many types of corrosion,
pitting is difficult to predict.

COMET will attempt to induce pitting in a stainless steel sample in
order to study it in the absence of gravity and determine what forces drive
this type of corrosion. This experiment has applications on Earth as well as
in space for preventing pitting in corrosive material piping systems.

The first three experiments are from students at the University of
Alabama in Huntsville while the fourth experiment is from students at the
University of Alabama in Birmingham.

G-541
Customer: Swedish Space Corp., Solna, Sweden
Customer: Kjell Anflo
NASA Technical Manager: Barbara Milner

The purpose of this experiment is to study the breakdown of a planar
solid/liquid interface during crystal growth. A sample of Germanium treated
with Gallium will be processed during the flight.

The experiment is performed in a gradient furnace. In this furnace,
which was developed for the previous G-330 flight, the growth rate can be
controlled along the length of the crystal. The furnace is designed with
electro-dynamic control of the temperature with a gradient moving along the
sample.

First the sample is heated up, melted and a controlled temperature
gradient of 20 degrees Celsius is established. It is important to keep a short
part of the sample solid because this part acts as a monocrystal seed.
Subsequently the absolute temperature is decreased but the temperature gradient
is maintained. The rate of the solidification front is kept constant at
approximately 1 mm/sec. The dopant (an impurity added to a pure substance to
produce a deliberate change) concentration along the sample is higher in the
hot end. The interface will become unstable and will break down when the
solidification front reaches the part of the sample where the dopant
concentration increases.

The interface demarcations are expected to reveal the development of
the size of the disturbances and the wavelengths during interface breakdown.
The thermo-couples and spreading resistance measurements will give accurate
data of temperature gradients and dopant concentration, respectively.

The payload consists of the following subsystems:

* Multi Zone furnace, ceramic tube with five heating elements and a
cooler
* Sample cooling system, low pressure internal cooling system
* Mechanical structure
* Microprocessor-based system for control of the experiment, data
handling and housekeeping
* Accelerometers
* Energy system, sealed lead batteries (1375 Wh)

Other GAS hardware

GAS hardware also is being used by the U.S. Postal Service to fly
500,000 commemorative stamps in recognition of the 25th anniversary of the
Apollo 11 Moon Landing. The stamp that is being flown is a $9.95 Express Mail
stamp. Artwork for the stamp was created by the father and son team of Paul
and Chris Calle, experienced stamp designers and participants in the NASA Art
Program.

The new stamp shows two astronauts on the moon's surface with the
Apollo landing module. The Express Mail stamp will be sold individually and in
panes of 20 stamps.

SECONDARY PAYLOADS


COMMERCIAL PROTEIN CRYSTAL GROWTH (CPCG)

The Commercial Protein Crystal Growth (CPCG) experiment has several
objectives. One objective is to grow and retrieve highly structured protein
crystals of sufficient size and quality to analyze the molecular structures of
various proteins. Another objective is to obtain information on the dynamics
of protein crystallization, allowing scientists to determine the parameters
necessary to optimize scientific methods for producing large, high quality,
well- ordered crystals.

The CPCG experiment will be flown in what is known as a Block I
configuration for STS-68. This configuration includes the utilization of one
Commercial Refrigerator/Incubator Module (CRIM) to maintain a specific profile
for three Vapor Diffusion Apparatus (VDA) trays. Each VDA tray contains 20
double-barrel syringes which empty into individually sealed sample chambers.
Each syringe contains a protein solution in one barrel and a precipitant
solution in the other barrel.

The 20 syringes are ganged together on each of the VDA trays so that
all the syringes on one VDA tray are deployed by one crew operation. The
liquids in the syringes are deployed and retracted several times to adequately
mix the protein and precipitant solutions. The final liquid deployment from
the syringes leaves the fluid drop hanging on the end of the syringe tip. This
configuration mimics a typical "hanging drop" configuration that is widely used
for ground-based crystallization processes driven by vapor diffusion.

The growth chamber surrounding the syringe tip contains a reservoir
with a highly concentrated solution of precipitating agent. The
crystallization process is driven by the difference in the vapor pressures of
the hanging drop and the reservoir solution. Water vapor is transported from
the hanging droplet of protein/precipitant solution to the reservoir solution
of precipitating agent. Protein crystallization is initiated when the
protein/precipitant concentrations within the hanging drop are altered by this
vapor transport. When a unique protein/precipitant concentration for a
particular sample is obtained in each of the growth chambers, crystallization
occurs.

Biological Research in Canisters P BRIC-01

STS-68 will fly the first in a new series of life sciences experiments
titled, "Biological Research in Canisters (BRIC)." BRIC experiments, sponsored
by NASA's Office of Life and Microgravity Sciences and Applications, are
designed to examine the effects of microgravity on a wide range of
physiological processes in higher order plants and arthropod animals (e.g.,
insects, spiders, centipedes, crustaceans). BRIC hardware consists of a small,
self-contained, two- chambered aluminum container that requires no power. The
first BRIC experiment (BRIC-01) will fly gypsy moth eggs to determine how
microgravity affects the developing moth's diapause cycle. The diapause cycle
is the period of time when the moth is in a dormant state and undergoing
development. Previous spaceflights of gypsy moths have indicated that
microgravity may shorten the diapause cycle which leads to the emergence of
sterile gypsy moth larvae. Since the gypsy moth is among the most damaging
insect pests of hardwood trees in the eastern United States, extensive
ground-based research has been conducted to modify the gypsy moth's life cycle
to create sterile moths. Results from NASA's BRIC-01 experiment could greatly
enhance these research efforts. The investigator for this experiment, Dr. Dora
K. Hayes, is a scientist with the U.S. Department of Agriculture in Beltsville,
Md., in the Livestock Insects Laboratory.

CHROMEX-05

STS-68 marks the fifth flight in the series of CHROMEX experiments
designed to examine the effects of microgravity on a wide range of
physiological processes in plants. CHROMEX experiments are flown in the Plant
Growth Unit (PGU), an automated system that provides lighting, limited
temperature control, and nutrients to support plant growth in the Shuttle
middeck. Previous CHROMEX experiments (CHROMEX- 03 and 04) indicate that
plants grown in space may not produce seed embryos. The primary objective of
CHROMEX-05 is to determine if plants grown in space are infertile due to
microgravity or some other environmental factor. For this experiment, 13-day
old Mouse-ear Cress (Arabidopsis thaliana) seedlings will be grown in space and
will be compared to plants grown under similar conditions on the Earth. Results
from this experiment will advance the field of space biology and will benefit
the development of planned plant-based life support systems for future long
duration space crews. Results may also benefit the nation's horticulture
industry which produces plants under artificial conditions (e.g., aquaculture).
The principal investigator for the primary experiment is Dr. Mary Musgrave, an
associate professor in the department of Plant Pathology and Crop Physiology in
the Louisiana Agricultural Experiments Station of the Louisiana State
University Agricultural Center. The CHROMEX experiments are sponsored by NASA's
Office of Life and Microgravity Sciences and Applications.

COSMIC RADIATION EFFECTS AND ACTIVATION MONITOR (CREAM)

The Cosmic Radiation Effects and Activation Monitor (CREAM) experiment
on STS-68 is designed to collect data on cosmic ray energy loss spectra,
neutron fluxes and induced radioareater brightness than the surrounding clouds.
The STS-68 crew will photograph ship tracks using handheld cameras. These
high-resolution photographs will provide insight into the processes of ship
track production on a global scale. MAST will help in understanding the
effects of man-made aerosols on clouds and the resulting impact on the climate
system. MAST is a Department of Defense payload and is being flown under the
direction of the DoD Space Test Program.





STS-68 CREW BIOGRAPHIES

Michael (Mike) A. Baker, 40, Capt., USN, will be Commander
(CDR) of STS-68. Selected as an astronaut in 1985, Baker
considers Lemoore, Calif., his hometown and will be making his
third Shuttle flight.

Baker graduated from Lemoore Union High School in 1971 and
received a bachelor's degree in aerospace engineering from the
University of Texas in 1975.

Baker's first Shuttle flight was as pilot aboard Atlantis'
STS-43 mission in August 1991, a mission that deployed the fifth
NASA Tracking and Data Relay Satellite. His second flight was as
pilot of STS-52 in October 1992, a mission that deployed the
Italian Laser Geodynamic Satellite and operated the first United
States Microgravity Payload.

Baker has logged more than 450 hours in space and more than
4,300 hours of flying time in 50 different types of aircraft.

Terrence (Terry) W. Wilcutt, 44, Major, USMC, will be Pilot
(PLT) of STS-68. Selected as an astronaut in 1990, Wilcutt
considers Russellville, Ky., his hometown and will be making his
first Shuttle flight.

Wilcutt graduated from Southern High School, Louisville, Ky.,
in 1967 and received a bachelor's degree in math from Western
Kentucky University in 1974.

After graduating from college, Wilcutt taught high school math
for two years before joining the Marine Corps. Wilcutt earned
his wings in 1978 and had initial training in the F-4 Phantom
aircraft. He later attended the Naval Fighter Weapons School
(Top Gun) and made two overseas deployments to Japan, Korea and
the Philippines. In 1986 he attended the Naval Test Pilot School
and graduated with distinction. He then served as a test pilot
and project officer for the Strike Aircraft Test Directorate,
Patuxent River, Md., until his selection by NASA.

Wilcutt has over 3,000 flight hours in more than 30 different
types of aircraft.

Thomas (Tom) D. Jones, 39, Ph.D., will be Payload Commander
and Mission Specialist 4 (MS4) on STS-68. Selected as an
astronaut in 1990, Jones was born in Baltimore, Md., and will be
making his second space flight.

Jones graduated from Kenwood Senior High School, Essex, Md.,
in 1973; received a bachelor's degree in basic sciences from the
Air Force Academy in 1977; and received a doctorate in planetary
science from the University of Arizona in Tucson in 1988.

Jones served as an Air Force officer for six years, flying
strategic bombers at Carswell AFB, Texas, and accumulating more
than 2,000 hours of jet experience. He resigned his commission
in 1983 and began work on his doctorate as a graduate research
assistant. Following graduation in 1988, he served as a program
management engineer in the CIA's Office of Development and
Engineering. In 1990, he joined Science Applications
International Corp., as a senior scientist, working on advanced
program planning for the Solar System Exploration Division at
NASA Headquarters, Washington, D.C.

Jones' first flight was as a mission specialist on STS-59 in
April 1994, the first flight of the Space Radar Lab. He has
logged more than 269 hours in space.

Steven (Steve) L. Smith, 35, will be Mission Specialist 1
(MS1). Selected as an astronaut in 1992, he considers San Jose,
Calif., his hometown and will be making his first space flight.

Smith graduated from Leland High School in San Jose in 1977;
received a bachelor's degree in electrical engineering from
Stanford University in 1981; received a master's degree in
electrical engineering in 1982 from Stanford; and received a
master's degree in business administration in 1987 from Stanford.


Smith worked for IBM in the Large Scale Integration Technology
Group in San Jose from 1982-1985, working on the development of
electron beam chemical and lithographic processes for
semiconductors. After a leave to pursue graduate studies, Smith
returned to IBM's Hardware and Systems Management Group in Santa
Clara, Calif., as a product manager for voice and telephony
products.

Smith joined NASA in 1989, serving in the Payload Operations
Branch, Mission Operations Directorate, at the Johnson Space
Center. He supported STS-37, STS-48, and STS-49 as a Payload
Officer in Mission Control before his selection as an astronaut.


Daniel (Dan) W. Bursch, 37, CDR., USN, will be Mission
Specialist 2 (MS2). Selected as an astronaut in 1990, Bursch
considers Vestal, N.Y., his hometown and will be making his
second space flight.

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

Bursch's first Shuttle flight was as a mission specialist on
STS-51 in September 1993, a mission that deployed the Advanced
Communications Technology Satellite and the Orbiting Retrievable
Far and Extreme Ultraviolet Spectrometer/Shuttle Pallet
Satellite.

Bursch has logged more than 236 hours in space and more than
2,100 hours flying time in over 35 different ircraft.

Peter (Jeff) J.K. Wisoff, 36, Ph.D., will be Mission
Specialist 3 (MS3). Selected as an astronaut in 1990, Wisoff
considers Norfolk, Va., his hometown and will be making his
second space flight.

Wisoff graduated from Norfolk Academy in 1976; received a
bachelor's degree in physics from the University of Virginia in
1980; received a master's degree in applied physics from Stanford
University in 1982; and received a doctorate in applied physics
from Stanford in 1986.

After completing his doctorate, Wisoff joined the Rice
University faculty in the Electrical and Computer Engineering
Department, researching the development of new vacuum ultraviolet
and high intensity laser sources and the medical application of
lasers to the reconstruction of damaged nerves.

His recent work includes collaboration with researchers at
Rice University on developing new techniques for growing and
evaluating semiconductor materials using lasers.

Wisoff's first flight was as a mission specialist on STS-57, a
mission that retrieved the European Retrievable Carrier satellite
and was the first flight of Spacehab. He has logged more than
239 hours in space.