WASHINGTON, May 23 (Xinhua) -- A pair of NASA astronauts on Tuesday successfully replaced a failed computer relay box outside the International Space Station during a short spacewalk that lasted less than three hours, the U.S. space agency said.
"We've declared victory on the installation of this replacement," a NASA TV commentator said about two hours into the contingency spacewalk conducted by astronauts Peggy Whitson and Jack Fischer.
The relay box, known as a multiplexer-demultiplexer (MDM), failed on Saturday. It is one of two units that regulate the operation of radiators, solar arrays and cooling loops.
The cause of the MDM failure is not known, but because each MDM is capable of performing the critical station functions, the crew on the station was never in danger and station operations have not been affected, NASA said.
A similar MDM replacement spacewalk was conducted in April 2014.
Typical spacewalks last about six and a half hours, but Tuesday's spacewalk lasted just two hours and 46 minutes.
During the spacewalk, the two astronauts also installed a pair of antennas on station to enhance wireless communication for future spacewalks, the space agency said.
