Space station computers partially back on line

By Irene Klotz

CAPE CANAVERAL, Florida (Reuters) - Russian flight controllers successfully restored two of the International Space Station's main computers on Friday, as spacewalking U.S. astronauts fixed insulation damage on the visiting space shuttle Atlantis.

A third system remained shut down and the cause of the failure remained a mystery. Friday's progress was the most encouraging since the computers crashed on Wednesday.

The computers control the station's positioning in space so that it can draw power from the sun, maintain proper temperatures and position antennas for communicating with ground controllers.

The German-built computers also command critical life-support equipment, such as the oxygen generators and scrubbers that remove deadly carbon dioxide. Those machines can be manually controlled as well.

Russian engineers have determined that one or two of the systems' backup power supplies have failed, prompting flight controllers to move up by two weeks the launch of a resupply ship with spare parts, said NASA space station program manager Mike Suffredini.

The computer crash was not considered life-threatening to either the station or shuttle crews.

The most pressing problem, Suffredini said, is to recover some ability to steer the station, which is vulnerable to bumps and vibrations from departing and arriving spaceships.

The shuttle is scheduled to leave the outpost on Tuesday, but NASA is considering leaving it for another day or two to help with recovery efforts.