The countdown for the launch of Space Shuttle
mission STS-101 is on schedule today leading to a launch at 4:15 p.m. on Monday,
April 24. The final launch time will be adjusted slightly during the T-9 minute
built-in hold based on the exact location of the orbiting International Space
Station.
The orbiter's aft main engine compartment is
closed out for flight. Cryogenic servicing of the fuel cell storage tanks
located beneath the payload bay was finished at 9:30 p.m. Saturday night.
This afternoon the orbiter communications systems
will be turned on and checked out. Space Shuttle and launch pad closeouts are
continuing today and will be completed tonight after the retraction of the
gantry-like rotating service structure scheduled for 8 p.m. Personnel will begin
clearing the launch pad at 2 a.m. in preparation for cryogenic operations.
Filling the external tank with liquid hydrogen and liquid oxygen will begin at
approximately 7 a.m. and should be complete at about 10 a.m.
Commander Jim Halsell and Pilot Scott Horowitz
flew the Shuttle Training Aircraft early this morning and the other astronauts
are expected to fly the T-38 jet trainers today. They will also conduct a final
inspection of Space Shuttle Atlantis at Launch Pad 39-A, receive a status
briefing on the countdown and the payloads and review their flight plans.
Weather forecasters indicate a 30 percent chance of launch weather criteria
violation on launch day. The forecast calls for scattered clouds at 4,000 –
7,000 feet and broken clouds at 25,000 – 31,000 feet; visibility at 7 miles;
winds out of the south-southeast at 12 gusting to 18 knots; temperature at 77
degrees F and relative humidity at 65 percent. The primary concern is a slight
potential for thunderstorms or associated anvil clouds.
The 24-hour and 48-hour delay forecasts indicate
a 60 percent and 20 percent chance of violation respectively.
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