A pair of NASA astronauts replaced a dead backup computer on the International Space Station during a short spacewalk Wednesday (April 23) to restore a critical computer system back to full strength.
NASA astronauts Rick Mastracchio and Steve Swanson made quick work of their repair during the spacewalk, removing the faulty station computer and installing a spare less than an hour after floating outside the orbiting laboratory at 9:56 a.m. EDT (1356 GMT).
"It looks like a good day for you guys to take a walk in space," Mission Control radioed the astronauts as the spacewalk began. The spacewalk was slated to last only 2.5 hours. [See photos from today's spacewalk]
Mastracchio and Swanson replaced a computer known in NASA parlance as a Multiplexer-Demultiplexer, or MDM. The device is a backup computer for routing commands to systems supporting the space station's solar arrays, robotic arm rail car and other critical systems along the station's backbone-like main truss.
The 10-year-old MDM computer failed on April 11 during a standard test. The primary computer in the system is working fine, but NASA station flight controllers ordered today's repair spacewalk to restore redundancy in the system.
"Looks like we've got a new MDM," Mastracchio said as he finished the job.
A quick test showed the new computer was working fine.
"Oh wonderful," Mastracchio said.
There are 45 MDM computers on the International Space Station, with 21 of them located on the orbiting lab's exterior and the rest installed inside the station's habitable area. Replacing the MDM computer boxes is one of 12 core space station repair skills astronauts learn before launch, NASA officials have said.
Despite their swift work, the spacewalkers did take time to marvel at the bright blue Earth below. At one point, Mastracchio reminded Swanson to take a look down at the sunlit Earth.
"Where are we?" Mastracchio asked Mission Control later. The answer: Over South America.
"A great view," the astronaut replied.