November 21, 2008
Second Spacewalk Comes To An End
As astronauts aboard the International Space Station prepared for a half-day off from work on Friday, they re-fired the shuttle's thrusters and began installation of a contraption that will recycle urine into drinking water.
Endeavour's seven astronauts and the three space station crew members have been working without a break since the space shuttle launched from Florida a week ago. They will get a half-day off in space after holding a news conference.
The extra thrust given on Friday will put the space station in prime location to receive a Russian Progress spaceship scheduled to deliver cargo to the orbiting outpost three days after Endeavour starts heading back to Earth on Thanksgiving.
A caution alarm complicated plans to test a batch of urine through the recycling contraption. Flight controllers believe it was a false alarm because they didn't notice smoke or a combustible odor.
"These are the growing pains we expect to see," said flight director Ginger Kerrick. "These are very complicated pieces of equipment with very complicated software to control them."
Samples from the contraption will have to be analyzed on Earth before station crew members can use the machine sometime next year.
Just as the alarm on the urine recycling system went off inside the space station Thursday evening, Heidemarie Stefanyshyn-Piper and Shane Kimbrough completed their second of four spacewalks with two minor complications. Kimbrough had trouble communicating with Mission Control and also had elevated levels of carbon dioxide in his spacesuit. Neither problem put the astronaut in danger.
"The (carbon dioxide) level never got to a level that we would have been concerned that it would cause him any problems," said John Ray, lead spacewalk officer. "We were just managing it to make sure we got him inside before it got to that level, and we did."
During the first spacewalk on Tuesday, Stefanyshyn-Piper's tool bag drifted out of reach while she was trying to clean grease leaked from a gun used to lubricate a jammed solar wing joint outside the space station.
Image Caption: Space Shuttle Endeavour (STS-126) and the International Space Station's robotic Canadarm2 (foreground) are featured in this view while Endeavour is docked with the station. A blue and white Earth and the blackness of space provide the backdrop for the scene. (NASA)
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