A pair of U.S. astronauts successfully completed their second spacewalk in two weeks on Thursday to perform maintenance work outside the International Space Station, including retracting a thermal radiator that is no longer in use.

"Spacewalk concludes @ 2:41pm ET (1841 GMT)," U.S. space agency NASA said via Twitter. "NASA_Astronauts completed all planned tasks + a few extra."

The spacewalk, the second for Commander Jeff Williams and flight engineer Kate Rubins in just 13 days, lasted six hours and 48 minutes.

Williams and Rubins first successfully retracted a thermal radiator that is part of the space station's cooling system. The radiator is a backup that had been deployed previously as part of an effort to fix an ammonia coolant leak.

Then, the duo installed two enhanced high definition cameras on the station's truss and tightened bolts on a joint that enables one of the station's solar arrays to rotate, NASA said.

This is the fifth spacewalk in Williams' career and the second for Rubins. They installed one international docking adapter on the station to enable the future arrival of U.S. commercial crew spacecraft during their previous spacewalk on Aug. 19.

Source : XINHUA