STS-93 Day 4 Highlights
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- On Sunday, July 25, 1999, 7:00 p.m. CDT, STS-93 MCC Status Report # 7
- The five astronauts aboard the Space Shuttle Columbia began their
fourth flight day at 4:31 p.m. CDT, preparing to make additional
celestial observations through the shuttle's windows and continue work
with a variety of experiments.
- The day started off with a wake-up call sent up in honor of Pilot
Jeff Ashby. It was a song called "Some Day Soon," written
by Judy Collins and performed by Suzy Boguss.
- The first job for Ashby and Mission Specialists Steve Hawley and
Michel Tognini was to set up an exercise treadmill and the Treadmill
Vibration Information System (TVIS) which will measure vibrations and
changes in microgravity levels caused by on-orbit workouts. These
workouts are needed to maintain astronauts' cardiovascular fitness and
muscle tone, which can suffer in the absence of gravity. Each
crewmember was scheduled to take a turn on the treadmill before it is
put away at the end of the day.
- Astronomer Hawley once again is scheduled to make observations of
Jupiter, Venus and the Moon with the Southwest Ultraviolet Imaging
System (SWUIS) as Commander Eileen Collins and Ashby put the shuttle
in the proper orientation for his observations.
- Tognini and Mission Specialist Cady Coleman will check on the
bioprocessing experiments, and harvest mouse-ear cress plants as part
of the Plant Growth Investigations in Microgravity experiment. These
genetically engineered plants are expected to yield clues to the
sensitive mechanisms the plants use to monitor their environment and
help scientists develop plants that respond better to the stresses of
- Collins and Ashby will fire the shuttle's engines so that the
sophisticated sensors of the Midcourse Space Experiment (MSX)
satellite will be able to collect ultraviolet, infrared and visible
light data on the firing. The satellite was launched from Vandenberg
Air Force Base in California in 1996. The commander and pilot also
will practice landings on a laptop computer, simulation software and
joystick combination called the Portable In-Flight Landing Operations
- Meanwhile, Mission Operations' Wayne Hale reported that engineers on
the ground continue to evaluate the short in one of the shuttle^Òs
electrical systems, which occurred shortly after launch as well as the
slightly reduced performance of the main engines. Neither problem
poses any risk to the remainder of the mission, Hale said.
- Hale said the crew's discovery that a circuit breaker had popped
during the climb to orbit provides reassurance that the problem has
been isolated and will not affect any of the shuttle's other
electrical systems used for reentry and landing. He also said that the
right engine's reduced performance may have been due to a small
hydrogen leak in tubes that help cool the nozzle. While it won't be
confirmed until the shuttle returns to Earth, Hale said the evidence
pointing to the leak includes a slightly higher than normal
temperature in that engine, and launch photos showing a white streak
that could be escaping hydrogen.
- At this point, Columbia is flying smoothly, orbiting the Earth every
90 minutes at an altitude of 182 statute miles.
- On Sunday, July 26, 1999, 6:00 a.m. CDT, STS-93 MCC Status Report # 8
- Columbia's astronauts entered the homestretch of their mission
this morning, conducting additional experiments in the Shuttle's
middeck area as they began preparations for their scheduled return to
Earth late Tuesday night.
- Commander Eileen Collins, Pilot Jeff Ashby and Mission Specialists
Cady Coleman, Steve Hawley and Michel Tognini completed work with the
Southwest Ultraviolet Imaging System, a telescopic instrument mounted
on the side hatch window in the middeck which has collected
ultraviolet data on the moon, Jupiter and Venus. Additional work was
conducted with several experiments studying the reaction of biological
samples and plant growth to the absence of gravity.
- Collins and Ashby fired Columbia's orbital maneuvering system
engines and its reaction control system jets several times to provide
more data for a pair of experiments examining how engine exhaust
disturbs the molecules in the ionosphere in low Earth orbit.
- Ashby, Hawley and Tognini took turns on a special treadmill set up
in the middeck which was equipped with accelerometers and sensors to
measure how well the device can offset vibrations induced by crew
exercise. Engineering data from the treadmill may be used by
technicians in the development of exercise equipment for the
International Space Station designed to minimize disturbances to
delicate microgravity experiments.
- Tognini and Collins took time out to field questions from French
Space Agency officials and students in Toulouse, France near the end
of the crew's work day and Collins was joined by Ashby to discuss
the progress of the mission with U.S. television networks and local
television affiliates in upstate New York.
- With all of Columbia's systems functioning in excellent shape,
NASA managers will be discussing landing opportunities and weather
forecasts for Florida in advance of the astronauts' final full day
- Current forecasts call for mostly clear skies and a possibility of
thundershowers near the 3-mile long landing strip at the Kennedy Space
Center for Columbia's planned touchdown tomorrow night at 10:20
p.m. Central time. A backup landing opportunity is available at the
Florida spaceport 90 minutes later.
- The five crew members will begin an eight-hour sleep period at 7:31
a.m. Central time this morning and will be awakened at 3:31 p.m. to
begin their fifth day in space. Collins and Ashby will check out
Columbia's flight control surfaces and fire the ship's reaction
control system jets tonight in the routine pre-landing checkouts
conducted the day before every shuttle landing, insuring that the
orbiter is in good shape to support the vehicle's high-speed return
- Columbia is orbiting at an altitude of 182 statute miles with all of
its systems in excellent condition.
- The next STS-93 status report will be issued late this afternoon
following crew wake up, or as developments warrant.
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