Glitch Forces Shuttle to Stabilize Space Station

The international space station was left unable to steer Wednesday after an unexplained problem with a ground-based computer in Moscow, but astronauts were able to use jets on the space shuttle Discovery, which was docked there, to maintain stable flight.

The cause of the problem had not been identified, but NASA said it hoped the station would resume attitude control by today.

“Clearly, until the fat lady sings, you don’t know what you’ve got,” said Mark Ferring, the space station’s lead flight director. “But based on my experience, it doesn’t seem to be a major problem.”

The Russians were updating computer software that commands large gyroscopes that hold the station stable as it circles the Earth at 5 miles per second. The operation had been planned for Discovery’s visit so the shuttle would be on hand, NASA spokesman Kyle Herring said.

Whatever the problem was, the Russians were unable to fix it before the station moved out of range of Russian ground stations.

“From all indications, what has happened is that they had some problem loading software on the ground. It’s not an on-board problem,” said Ferring, who added that Moscow’s mission control said it would have a fix during the next ground pass.

“We don’t have all the details, but it leads us to understand they already have a pretty good idea what they have to go do to recover from this,” he said.

If the problem is fixed quickly, there will be no reason to worry about the shuttle, which is using extra fuel to stabilize the complex. The shuttle and space station together have almost 400 tons of mass.

“We have enough gas for at least several days,” said John Shannon, the shuttle’s flight director. Shannon said NASA could not predict how long Discovery could stabilize the station because an exact forecast of fuel consumption was difficult.

Ferring said that if the problem was solely with ground computers, command of the gyroscopes could be switched to computers in the U.S. segment, but space officials decided to wait.

“We opted to take some time and let Moscow consider its options,” Ferring said.

A change of command from Russian skipper Yury Usachev to American Frank Culbertson was postponed because of hectic operations aboard the station. It was tentatively pushed back to Friday.

The new station crew, which actually took control of the station Monday with everything but the hand-over ceremony completed, was to spend its first night alone aboard the station Wednesday.