German astronaut Hans Schlegel has completed his spacewalk, apparently recovered from an undisclosed ailment that forced him out of an earlier spacewalk to attach Europe's Columbus laboratory to the International Space Station.
Hans Schlegel and American Rex Walheim replaced a depleted tank of nitrogen with a full one brought up by space shuttle Atlantis, which launched from Florida on Thursday.
‘Welcome to spacewalking,’ Rex Walheim told Hans Schlegel, who flew on a 1993 shuttle mission, but did not venture outside.
56-year-old Mr Schlegal said it was a good feeling.
He had been scheduled to participate in the first spacewalk of Atlantis' mission on Monday but sat out due to a medical condition that neither he, NASA nor the European Space Agency has disclosed.
He was cleared for yesterday's task and showed no ill effects during the nearly seven-hour spacewalk to install the 250kg tank.
Nitrogen is used to pressurise coolant lines.
Rookie astronaut Stanley Love replaced Mr Schlegel on Monday's outing in which he and Mr Walheim helped attach Columbus, also ferried up by Atlantis, to the $100 billion space station.
The gleaming, $1.9 billion module is Europe's first permanent space lab and its primary contribution to the station.
NASA decided on Wednesday to keep Atlantis in space an extra day so Mr Schlegel could do more work to set up experiments on Columbus.
The lab's activation was slowed by a problem getting computer commands from its command centre in Munich for much of Tuesday, space station flight director Sally Davis said.
The computers were reconfigured and are now working, she said.
On Friday, the third and final spacewalk planned during Atlantis' flight, astronauts Walheim and Love are scheduled to install a solar telescope and a materials science experiment on the outside of the Columbus module.
The extension of Atlantis' mission means the shuttle will stay at the station until Monday and return to Earth next Wednesday.
The next space shuttle mission, set for a 11 March launch, is scheduled to bring up the first piece of what will be the station's largest laboratory, the Japanese-built Kibo complex.
NASA is planning to fly 11 more shuttle missions to finish construction of the space station, which is 60 percent complete, before the aging shuttle fleet is retired in 2010.
