Russians fail to fix space station computers

An image from NASA TV shows the starboard solar array on the Port 6 (P6) truss that International Space Station crewmembers are working to retract June 14, 2007.

KOROLYOV, Russia (Reuters) - Russian engineers failed on Friday to fix malfunctioning navigational computers on the orbiting International Space Station but said they did not foresee having to evacuate the three crew.

The computers, some of which control thrusters that help keep the $100 billion station in a stable orbit, broke down on Wednesday shortly after the crew of the visiting U.S. space Shuttle Atlantis installed a new solar array for power.

"We have not so far managed to fully restore the computers," Nikolai Sevastyanov, chief constructor at Russian space company RKK Energiya, told a news conference at mission control in the town of Korolyov near Moscow.

"Tomorrow we'll try turning on secondary power sources using a new method. If that does not work we will not try again."

Space officials said it was so-called secondary power sources that had failed, rather than the German-built computers themselves or the Russian software that they run on.

If Saturday's attempts fail again, the Russian space program may launch a Progress supply ship from its cosmodrome in Baikonur in Kazakhstan on July 23, two weeks earlier than planned, with new power supplies on board, Sevastyanov said.

The malfunctioning units could be sent to Earth on the shuttle for further analysis. Russian officials said the station had 90 days of oxygen and could remain in orbit even with the malfunctioning computers.

The direct cause of the computer failure was a surge in static electricity when the new solar array was unfurled. It had been delivered by the visiting space Shuttle Atlantis.

"We don't believe that this is a case that will need evacuation," said Sergei Krikalyov, a former cosmonaut who has been on the space station three times and is a vice-president at Energiya.

NASA had said that a failure to fix the computers could force a temporary evacuation of the space station, a 16-nation project which has been continuously manned since November 2, 2000.

That unlikely worst-case-scenario would entail the three space station astronauts leaving in the escape ship, a Russian Soyuz capsule. The Atlantis crew would return to Earth on the shuttle.

Russian officials were careful not to point the finger of blame at the U.S.-led installation of the solar array.

"Maybe it was simply a fact of nature that can cause something like this," Krikalyov said. "I wouldn't like to find fault with anyone."

The six computers were restarted on Thursday and worked for three hours before breaking down again, Russian media reported.

The station mainly relies on big gyroscopes to maintain its proper orientation in space but also uses control jets and navigation systems run by the computers in its Russian section.