Landing Forecast No-Go; Station Computers Fail

Endeavour's astronauts face a daunting weather forecast for a planned landing at Kennedy Space Center tonight and their colleagues on the International Space Station are struggling with command-and-control computer crashes that caused a loss of communications with NASA's Mission Control Center in Houston.

The shuttle and its six astronauts remain scheduled to land at KSC at 10:20 p.m. tonight and would have a second opportunity at 11:55 p.m. NASA is staffing a back-up site at Edwards Air Force Base in California and there are two opportunities to land at the Mojave desert military base: 1:25 a.m. EST and 3 a.m. EST.

The weather at both landing sites, however, is forecast "no-go."

While the weather around KSC is excellent right now, the Spaceflight Meteorology Group at Johnson Space Center in Houston expects low cloud decks to sweep into the area by the scheduled landing times tonight. There also is a chance of rain showers within 30 miles of the landing strip. Those conditions would violate NASA flight rules.

Low-cloud decks and rain also are forecast at Edwards Air Force Base tonight.

The weather on Monday at KSC is expected to be worse. But conditions are expected to clear Monday at Edwards.

The astronauts nonetheless will begin deorbit preparations around 5:14 p.m. The shuttle's payload bay doors are scheduled to be closed at 6:30 p.m. and the crew is slated to perform a deorbit burn around 9:10 p.m.

Colleagues on the International Space Station, meanwhile, have been dealing with command-and-control computer failures since about 9 a.m.

The U.S. side of the station is equipped with three command-and-control computers that run all systems and provide for communications with the ground. One is primary, a second is back-up and the third remains on standby. The primary computer failed this morning, causing a loss of communications with Mission Control for about an hour. A series of failures followed, but all three computers since have been recovered.

Ground controllers are unsure what caused the failures. They might be related to new software that was beamed up to provide for operations in the new U.S. Tranquility Module. Troubleshooting is continuing and for the time being, Mission Control is being "selective" about sending up any commands to the station.