American astronauts have replaced a failed computer responsible for controlling critical systems outside the International Space Station (ISS) including solar panels.
During a two-hour emergency spacewalk on Wednesday afternoon flight engineers Rick Mastracchio and Steve Swanson removed the microwave-oven-sized unit, which failed on 11 April, and installed a new one.
The broken computer, also known as Multiplexer/Demultiplexer, was used as a back-up for the main unit, guiding the tilt of solar panels to track the Sun and position a mobile base for the station’s robotic crane. Its failure has not had any effect on the safety of the ISS crew.
"I don't see any obvious damage," Mastracchio said when inspecting the broken unit, which had been in service since April 2002 when it was delivered to the station already installed in a truss structure. The replacement unit had been stored in the station’s Destiny module since delivery in 2001.
The emergency spacewalk was only a second instance when Nasa allowed its astronauts to venture out in open space. Spacewalks run by the American space agency have been suspended since last year’s incident when Italian astronaut Luca Parmitano nearly drowned as his helmet filled with water due to a blocked filter.
During the emergency spacewalk to replace the computer, Mastracchio, making his ninth spacewalk, and Swanson, on his fifth, both had snorkels and pads in their helmets in case of another water leakage.
New spacesuits are among the cargo aboard the Space Exploration Technologies' Dragon capsule, which reached the station on Sunday.
Nasa expects to resume routine spacewalks for maintenance and less-pressing repairs in July.