STS-99 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 per cent 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 7:17am 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 their 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 afternoon.
The next status report will be issued Monday evening at approximately 6:00 p.m. CST.
