Spacewalking Repairmen Star in Juggling Act at Space Station

Two spacewalkers took on a quick computer repair job at the International Space Station on Wednesday, one of the crew's busiest days in orbit.

NASA astronauts Rick Mastracchio and Steve Swanson began the spacewalk at 9:56 a.m. ET, heading out to replace a backup computer box that failed less than two weeks ago. Japan's Koichi Wakata is playing a supporting role inside the station.

It has come to our attention that the browser you are using is either not running javascript or out of date. Please enable javascript and/or update your browser if possible.

Meanwhile, their Russian crewmates Mikhail Tyurin, Alexander Skvortsov and Oleg Artemyev helped out with a previously planned test of an automated rendezvous system installed on a robotic Progress cargo ship. The Progress was undocked early Wednesday morning and took up a position about 300 miles (500 kilometers) from the station to begin two days of tests.

All this is going on while a freshly arrived SpaceX Dragon cargo ship is docked to a different port on the station.

NASA flight director Brian Smith said it's unusual to schedule an extravehicular activity, or EVA, amid so many other tasks.

"This isn't a long EVA," Smith told reporters during a pre-spacewalk briefing. "There are certainly EVAs that are more complicated than this one. However, the real trick has been to figure out how to put this EVA in the same week that we're doing the Dragon mission and we're doing the 53P Progress operations."

The spacewalk was choreographed quickly because NASA doesn't want to go without a backup for this particular computer box any longer than necessary. The box, known as a multiplexer-demultiplexer, plays a role in controlling critical systems on the space station, including the solar arrays, a robotic rail car and the external cooling system.

Flight Engineers Rick Mastracchio and Steve Swanson (partially obscured) install a new circuit board inside a spare multiplexer-demultiplexer aboard the International Space Station.

The primary computer box is working fine, and the crew is in no danger. But Smith said he and other mission planners were concerned about the "next worst-case failure" that is, the loss of the primary computer while the backup is out of commission.

Read the rest here:
Spacewalking Repairmen Star in Juggling Act at Space Station