Space station computer replaced in short spacewalk

CAPE CANAVERAL, Fla. – Spacewalking astronauts easily replaced a dead computer outside the International Space Station on Wednesday and got their orbiting home back up to full strength.

The two Americans on board, Rick Mastracchio and Steven Swanson, hustled through the urgent repair job, swapping out the computers well within an hour. The new one tested fine.

The removed computer, a critical backup, failed nearly two weeks ago. The prime computer has been working perfectly, but NASA wanted to install a fresh spare as soon as possible.

Mission Control waited until after a capsule of fresh supplies arrived Sunday.

Replacing the computer – a compact 50-pound box – involved just three bolts, hardly anything for a spacewalking chore.

Engineers do not know why the original failed. Mission Control asked the spacewalkers to keep an eye out for any damage that might explain the breakdown. Nothing jumped out.

Flight controllers were trying to load software into the spare computer April 11, but it did not activate. That led to a frenzy of ground meetings and tests to fix the problem.

NASA feared that if the primary computer went down as well, the entire space station would be in jeopardy. The two computers – the primary and backup – control the pointing of the solar wings and radiators, as well as the movement of the robot-arm rail cart.

Mission Control kept the spacewalk short and straight-to-the-point; it lasted a mere one hour and 36 minutes. All routine spacewalks by U.S. station crew have been on hold since last summer’s near-drowning by a spacewalking astronaut.