STS-75 Day 10 Highlights
Back to STS-75 Flight Day 09 Highlights:
- On Saturday, March 2, 1996, 8 a.m. CST, STS-75 MCC Status Report # 19
- While science investigations continued on the middeck --
specifically studying how fire spreads and soot develops in the
microgravity environment of space -- a procedure was performed to
remove ice from the core of Columbia's flash evaporator system which
shutdown earlier this morning.
- The FES core flush procedure was identical to one carried out on the
last Shuttle flight to melt ice and recover use of the subsystem which
is designed as a subtle method for dumping excess water overboard
without disrupting the experiments on board. The FES also cools the
freon used to keep orbiter and payload electronics at operating
- Later today, Franklin Chang-Diaz (from Costa Rica) will be
interviewed by the Spanish NewsChannel and CNN International. Joining
him for the 4:30 interview are Andy Allen, Jeff Hoffman and Claude
- At 7:30 this evening, Jeff Hoffman with other available crew members
will receive a congratulatory call from organizers of the annual
Houston Livestock Show and Rodeo.
- Columbia's systems continue to operate well, providing a platform
for USMP operations in orbit 180 miles above the Earth.
- On Friday, March 1, 1996, 6 a.m. CST, STS-75 Payload Status Report # 15
reports: (8/15:42 MET)
- The future of high-technology electronics, metal alloys and
industrial chemical processes is the main benefactor from scientific
research in progress on the third United States Microgravity
Laboratory (USMP-3). But the future of space-based operations also is
being shaped by the "telescience," or remote control, capabilities of
USMP-3 researchers working at Spacelab Mission Operations Control in
Huntsville. From their unique vantage point, the USMP team is not
only gaining insight into the subtle laws of nature, they also are
directly interacting with their experiments on orbit.
- The Advanced Automated Directional Solidification Furnace (AADSF)
early today finished processing the first of three lead-tin- telluride
samples and prepared the "seed," or solid core, of their next sample's
crystal, scheduled for solidification tonight. The AADSF team is
studying how semiconductor crystals might be improved for applications
such as infrared detectors used by the aircraft industry and in
medical technology, and for such high- tech apparatus as night vision
goggles. Semiconductor performance is based, in large part, on
uniform distribution of elements for the best electrical properties.
Crystals such as these can be grown more uniformly in space.
- Telescience was a major tool that allowed AADSF researchers to delay
the start of their experiment when the seed, around which the sample
crystallization grows, was not indicated by the data. The team took a
careful second look at the real-time information they received and
halted the furnace. From this temperature data, they could determine
when the first seed formed. Based on that information, they regulated
the temperature and position of the second sample accordingly to
ensure proper seed formation. "We think the first solidification went
well," said Principal Investigator Dr. Archie Fripp of NASA's Langley
Research Center. "When we get the samples back and look at them with
eyes sharper than mine, such as an electron microscope, we'll know
- The ability to remote command the unique MEPHISTO furnace has
allowed its science team members to use a new strategy to improve
their data on the stability of their sample's shape. The approach
involves tracking small changes in the speed of their sample's growth
during several shorter and faster cycles of the furnace's processing.
During each cycle, the MEPHISTO experiment's high- temperature furnace
melts and re-solidifies a tin-bismuth mixture that acts very much like
the metal alloys used for products such as jet engine turbine blades
and electronic materials.
- MEPHISTO team members watch real-time data displays to "visualize"
the sample as it is being processed. Based on this and additional
real-time data analysis done in Toulouse, France, and at the
University of Alabama in Huntsville, Principal Investigator Dr.
Jean-Jacques Favier carefully analyzes and modifies the furnace's
temperature and position and rate of movement over the sample to
gather the highest quality science. "We are extremely excited to be
able to modify our sample's growth conditions in response to real-time
science data," he explained.
- Another experiment that utilizes a remote site to gather and analyze
data is the Isothermal Dendritic Growth Experiment (IDGE) team from
the Rensselaer Polytechnic Institute. Real-time analysis by IDGE
teams working at the Marshall Center and at the Rensselaer Remote
Operations Control Center, in Troy, N.Y., has greatly reduced the time
needed to perform each growth cycle of tree-like structures, or
dendrites, like those that form when metals solidify.
- Early data gathered by the Orbiter Acceleration Research Experiment
indicate that changes in the speed of such growths are not caused by
the effects of Columbia's movement and position on small fluid flows
in the IDGE experiment chamber. This information will become critical
in further discussions about the effects that minor disturbances, or
accelerations, have on dendrite growth. "Time is money. In our
limited time on orbit, typical pre-programmed experiments would have
missed out on a tremendous amount of science return if we had not been
able to adjust these growth cycles," explains IDGE Project Scientist
Ed Winsa of NASA's Lewis Research Center.
- The science team of the Critical Fluid Light Scattering Experiment,
or ZENO, also points out that remote commanding significantly reduces
on-orbit crew training time. These highly specialized investigations
are performed by those who know them best. "The ZENO data displays
are alive. We monitor over 100 channels of information and maintain
close personal contact with the experiment," explains Principal
Investigator Dr. Robert Gammon, of the University of Maryland.
Informed decisions are made by those who are most knowledgeable.
- ZENO team members have been closely watching how their experiment
responds to command adjustments. As the experiment's xenon sample
approaches ever closer to its critical temperature and density, in
which liquid and gas phases coexist, changes in Space Shuttle
Columbia's position become increasingly important. The science team
is working in close cooperation with mission flight controllers to
control the effect of these changes on their investigation.
- Over the next 24 hours, microgravity telescience aboard the STS-75
mission will continue, as the MEPHISTO experiment remains in its new
"short cycle" mode. The crew, meanwhile, is continuing to perform
more combustion experiments in the Middeck Glovebox, demonstrating the
importance of crew interaction in some experiments.
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