Robot arm handshake on hold

NASA information about the space station

For a second day, a computer "glitch" on the International Space Station delayed NASA's attempts to operate the newly installed robot arm.

NASA engineers and astronauts Thursday were able to restore one of the three command and control computers on the space station. All three computers went down on Wednesday. As of Thursday, however, NASA was unsure what the problem was.

Although the crew was able to get one of the three systems working again, NASA officials decided to postpone the test of the robot arm in an effort to get at least one of the back-up systems running. "We want to get a second computer running so we have some redundancy before we do those activities," said NASA spokesman Greg Lange at the Johnson Space Center in Houston.

The crews are seeking to conduct a "handshake" — a test where the space station's 58-foot robot arm will hand its 3,000-pound packing crate to the shuttle's robot arm.

The trade originally was scheduled for Wednesday, but was delayed because a computer server on the space station went down, disrupting communications onboard.

The troubled server feeds a main computer and two laptops aboard the station, which are then used to send commands to the robot arm, according to NASA.

The problem disrupted communications from the command computers on the station. All other systems were running properly, NASA officials said, and Mission Control in Houston remained in contact with the crew through space shuttle Endeavour, which is docked at the station.