Two astronauts of the US space shuttle Endeavour began Saturday the third mission spacewalk outside the orbiting International Space Station to complete repairs on one of the station's three double solar antenna arrays. Americans Heide Stefanyshyn-Piper, 45, and Steve Bowen, 44, headed out a bit early on the space walk, scheduled to last seven hours or more, the longest on the mission that began on November 15.
The space walk was scheduled to begin at 1845 GMT, but started about 45 minutes early. The two astronauts are tasked with finishing repairs to the ISS's starboard Solar Alpha Rotary Joint race ring and replacing trundle bearing assemblies. The worn-out parts will be taken to Earth for inspection.
By 1630 GMT Stefanyshyn-Piper and Bowen, both US navy captains, had finished putting on their bulky astronaut suits ahead of exiting the craft. The complex work in space is being orchestrated by Shane Kimbrough, 41, who was on a space walk along with Stefanyshyn-Piper on Thursday.
During an earlier space walk on Tuesday, Stefanyshyn-Piper let slip her tool bag and watched helplessly as it floated off into the void of space. Mission Control at the Johnson Space Center in Houston however said the work on the ISS's solar antenna rotation system would continue as planned.
Meanwhile, NASA experts continued to work on problems with a urine processor unit that is designed to process urine, perspiration and bath water into drinkable water. NASA said a centrifuge motor inside the distillation unit was running too slow and drawing too much electrical current.