Shuttle Prepares for Landing; Bad Weather May Change Plans

The crew of the space shuttle Discovery packed Thursday to come home after a mission that made history with its U.S.-Russian partnership but achieved mixed results on the science front.

Bad weather threatened to disrupt NASA’s landing plans. Forecasters were calling for possible rain, low clouds and high winds at the Kennedy Space Center, any one of which could prevent the shuttle from landing there as scheduled at 9:44 a.m. PST today.

Flight directors said they would consider sending Discovery to Edwards Air Force Base in California later in the day if necessary. Another option would be to keep the shuttle up an extra day.

Discovery’s five American astronauts and cosmonaut Sergei Krikalev, the first Russian to fly on a U.S. shuttle, have been in orbit since Feb. 3. During the past week, the crew completed its chores inside Spacehab, the small commercial laboratory in the cargo bay. Only one of the 12 Spacehab experiments--a cell-separation test--encountered major trouble.

The crew also finished all four joint U.S.-Russian experiments. Researchers from both countries will share the results of the medical and radiation measurements and Earth observations.

But the crew achieved only two of three planned satellite releases. The most important, deployment of the Wake Shield Facility, failed due to problems with the satellite.

The steel, saucer-shaped Wake Shield remained aboard instead of flying free for two days as intended. Physicists wanted to avoid shuttle contamination while developing semiconductor film on the Wake Shield; the film, if pure, could have led to faster computers.

Astronaut Ronald Sega, a physicist and engineer who spent years working on Wake Shield, said the experiment at least verified that thin semiconductor film can be produced in the vacuum of space. The Wake Shield is supposed to fly again on the shuttle next year.

A German science satellite released Wednesday circled Earth, as did six metal balls ejected as part of a study on space debris.

The crew took time Thursday to chat via ham radio with students at James Bean School in Sidney, Me., and Krikalev tried, without success, to contact the three cosmonauts aboard Russia’s Mir space station.