Florida ? Russian engineers worked feverishly Thursday to restore a key computer system on the international space station but made little headway.

Among other functions, the system controls the firing of Russian-made thrusters that keep the outpost positioned. After crashing earlier this week, the computers were rebooted briefly Thursday, then shut down for more troubleshooting.

In a worst-case scenario, a continued failure could force NASA and the Russians to abandon ship, with the station crew returning to Earth in a Soyuz capsule. However, NASA downplayed the possibility as highly unlikely.

“We’ve got plenty of time to work this problem, and we’ll figure out the right way to go do this in the next couple of days,” said Bill Gerstenmaier, NASA associate administrator for space operations at Cape Canaveral.

One suspect is the new pair of solar arrays that Atlantis and its crew delivered. Space station manager Mike Suffredini said the computers started malfunctioning soon after the $367 million segment was installed earlier this week.