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STS-99, Mission Control Center
Status Report # 21 Monday,
February 21, 2000 - 10:30 a.m. CST
Endeavour's astronauts
finished their successful Shuttle Radar Topography Mission mapping operations
early Monday, then retracted the system's 200-foot mast into its payload
bay canister. The mast, the longest rigid structure ever deployed in
space, supported the external antenna structure during more than 222
hours of data gathering that mapped almost 100 percent of all planned
sites around the world.
The mast folded
smoothly into its nine-foot-long canister in Endeavour's payload bay
during the 18 minute retraction operation that astronauts began at 7:17
a.m. Central Time. The crew flipped the outboard antenna structure over
to its stowed position, then began retracting the mast itself. As each
of the 86 bays of the mast entered the canister, the bay's corners were
captured in spiraling grooves inside the canister, much like those in
a rifle barrel.
Completion of the
final portion of stowing the SRTM mast was delayed when the three latches
on the lid of the mast canister failed to engage as expected. Suspecting
that the cold thermal temperatures the mast experienced while deployed
were reducing the flexibility of the system, flight controllers had
the astronauts work procedures to warm up the mast canister while increasing
the torque pull of the canister motors. The efforts of Endeavour's crew
and Mission Control were rewarded at 9:50 a.m. Central time when all
three latches on the mast canister closed, securing the SRTM payload
for the ride home to Earth.
Radar data gathering
concluded at 5:54 a.m. after a final sweep across Australia. During
222 hours and 23 minutes of mapping, Endeavour's radar images filled
332 high density tapes and covered 99.98 percent of the planned mapping
area - land between 60 degrees north latitude and 56 degrees south latitude
- at least once and 94.6 percent of it twice. Only about 80,000 square
miles in scattered areas remained unimaged, most of them in North America
and most already well mapped by other methods. Enough data were gathered
to fill the equivalent of 20,000 CD's.
The EarthKAM, a
digital camera mounted at an overhead window on Endeavour's flight deck,
has been shut down for the remainder of the flight, after sending to
Earth about 2,600 digital images of the planet's surface. On four previous
shuttle flights EarthKAM sent down a total of 2,018 images.
Later today, Endeavour's
crew will turn its attention to returning home. Check out of the flight
control surfaces and orbiter thruster jets is scheduled to begin at
noon. After the orbiter systems checks are complete, the crew will begin
stowing the cabin for tomorrow's return to the Kennedy Space Center
with landing scheduled for 3:50 p.m. Central Time Tuesday.
The next status
report will be issued Monday at approximately 6:00 p.m. CST.
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