STS-90 Day 16 Highlights
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- On Saturday, May 2, 1998, 6:00 a.m. CDT, STS-90 MCC Status Report # 31
- With nearly all of their science studies complete, Columbia's
astronauts were awakened at 3:29 a.m. CDT today to begin a busy day
preparing for their return to the Kennedy Space Center.late Sunday
- Commander Rick Searfoss is scheduled to route a line from
Columbia's waste tank to a Contingency Waste Container (CWC) to
offload about 80 pounds of waste water throughout the course of the
day. This will ensure that the tank's capacity will be adequate to
support as much as two additional days in orbit in the event Columbia
cannot land as planned due to weather conditions.
- Columbia's science crew -- Mission Specialists Rick Linnehan and
Dave Williams and Payload Specialists Jim Pawelczyk and Jay Buckey --
will wrap up science activities this morning when they complete some
vestibular experiments. Crew members also will begin cabin stowage
- Commander Rick Searfoss, Pilot Scott Altman and Mission Specialist
Kay Hire will conduct a hot-fire test of the shuttle's reaction
control system to ensure Columbia's readiness for tomorrow's entry
and landing. About an hour later, they will activate one auxiliary
power unit and check out the flight control system to make sure
Columbia has full use of its flight control surfaces in anticipation
of Sunday's landing. They also will conduct landing simulations with
the Portable In-flight Landing Operations Trainer (PILOT). The
astronauts will conduct a deorbit briefing among themselves early in
- Payload commander Rick Linnehan will replenish water supplies and
carry out other routine husbandry tasks for the rodents on board and
the science crew will put away experiment hardware and partially
deactivate the Spacelab module. Columbia's KU-band communications
antenna also will be stowed just before 11 a.m. today.
- Meteorologists are forecasting favorable conditions at the Kennedy
Space Center on Sunday for a landing at 11:09 a.m. CDT.
- Columbia remains in a 150 x 131 nautical mile orbit, circling the
Earth every 90 minutes.
- On Saturday, May 2, 1998, 5:00 p.m. CDT, STS-90 MCC Status Report # 32
- With all science activities complete on board, Columbia's seven
astronauts readied their ship for a Sunday landing at Kennedy Space
- The science crew ^V Mission Specialists Rick Linnehan and Dave
Williams, and Payload Specialists Jim Pawelczyk and Jay Buckey --
wrapped up science activities this morning with final studies focusing
on how the vestibular system adapts in a changing environment.
- To prepare for tomorrow's return to Earth, the flight crew
Commander Rick Searfoss, Pilot Scott Altman and Mission Specialist Kay
Hire conducted a successful test of the shuttle's reaction control
system jets and flight control surfaces. For the check out of the
flight control surfaces, the astronauts started Auxiliary Power Unit
#3, one of three hydraulic units on board, to provide hydraulic power
to the surfaces and to verify that its cooling system was working
properly after an apparent freeze-up during Columbia's launch two
weeks ago. The FCS checkout was completed successfully, but APU 3^Rs
cooling system did not function as expected.
- The failure of the cooling system for APU 3 will not affect
Columbia's landing tomorrow and a minor modification to managing the
auxiliary power units will be implemented by entry Flight Director
John Shannon. Following standard deorbit procedures, one APU will be
started five minutes prior to the scheduled deorbit burn. At a point
13 minutes before Columbia encounters the first traces of the
atmosphere, when the remaining two APU's are normally brought on
line, only one additional APU will be started. APU 3 will be powered
on about six minutes prior to landing when Columbia's speed is about
Mach 2.5. The auxiliary power units are capable of operating for 10
to12 minutes before their cooling systems would be required.
- Commander Rick Searfoss successfully dumped about 70 pounds of waste
water into a Contingency Waste Container (CWC) this morning, This will
ensure sufficient stowage capacity in the waste tank to support as
much as two additional days in orbit in the event Columbia does not
land on Sunday.
- Payload commander Rick Linnehan replenished water supplies and
performed some routine husbandry tasks for the rodents on board and
completed a partial deactivation of the Spacelab module. Final
deactivation of Spacelab systems is set for tomorrow
morning. Columbia's Ku-band communications antenna also was stowed
about 11:30 a.m. today.
- Columbia has two opportunities to land at the Kennedy Space Center
on Sunday. The first would see a deorbit firing of the orbital
maneuvering system engines at 10:11 a.m. CDT, with landing at 11:09
a.m. In the event flight controllers elect to bypass the first
opportunity, there is a second opportunity that would see a deorbit
burn at 11:44 a.m. with a landing to follow at 12:43
p.m. CDT. Preliminary weather forecasts for Sunday show clear skies in
the vicinity of the Kennedy Space Center. with the only potential
issue the possibility of high cross winds. The current forecast
indicates the winds should stay within acceptable limits.
- By Monday, a weather front is expected to approach KSC, bringing
with it the possibility of low cloud ceilings and rain
showers. Weather at the alternate landing site at Edwards Air Force
Base in California is expected to be good through Tuesday.
- The next STS-90 status report will be issued following Columbia^Rs
landing at the Kennedy Space Center. or after a wave-off of Sunday
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