November 24, 2008

Endeavor Crew Complete Fourth, Final Spacewalk

Endeavor astronauts ventured out on their fourth and final spacewalk on Monday.

Meanwhile, astronauts inside continued work on a system that converts urine to drinking water on the International Space Station.

Astronauts Stephen Bowen and Robert "Shane" Kimbrough hoped to complete work on lubricating a joint that keeps a power-generating solar wing on the space station's right side facing the sun. Once completed, the wing will be able to produce a much larger amount of energy, allowing for the orbiting outpost's crew to expand from three to six residents next year and allow more research 220 miles above Earth.

"We're going to need every watt of that power," said space station commander Michael Fincke.

The shuttle had been due to depart on Thursday, but NASA has had problems with a piece of equipment delivered to the station that is needed to prepare the orbital outpost to support an expanded, six-member crew. They also plan to lubricate a similar joint for the station's left solar wing. Other tasks include installing a video camera, spacewalk handrail and GPS antenna, as well as taking photos of equipment.

During the crew's first spacewalk last week, lead spacewalker Heide Stefanyshyn-Piper watched as a $100,000 tool kit floated out of reach. NASA said the tool kit was the largest loss reported from any mission.

That forced flight controllers to choreograph the other spacewalks with only one pair of grease guns. Endeavour commander Christopher Ferguson said Sunday that the shuttle's spacewalkers had overcome that loss with aplomb.

"We're jacking up the international space station, taking the wheels off, and we're bound to get a little dirty, a little dusty and meet a few surprise along the way," Ferguson said. "I think we've weathered this one just fine and come back with a lot of confidence."

Inside the space station, astronauts spent a fourth day Sunday trying to get a urine processor working. The processor is part of the newly delivered $154 million system that converts urine, sweat and condensation into drinking water.

Endeavour undocks from the space station on Thanksgiving Day and returns to Earth on Saturday.


Image 1: Astronaut Chris Ferguson, STS-126 commander, watches bubbles float freely on the middeck of Space Shuttle Endeavour while docked with the International Space Station. NASA

Image 2: Astronaut Steve Bowen, STS-126 mission specialist, participates in the mission's third scheduled session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the six-hour, 57-minute spacewalk, Bowen and astronaut Heidemarie Stefanyshyn-Piper (out of frame), mission specialist, focused their efforts on the continued cleaning of the station's starboard solar alpha rotary joint (SARJ) and the removal and replacement of trundle bearing assemblies (TBA). Bowen and Piper also cleaned the area around the SARJ's drive lock assemblies, which help the joint to rotate and lock into place. NASA


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