Image above: Mission Specialist Greg Chamitoff removes spacewalker Steve Bowen's spacesuit helmet following the first spacewalk of the STS-126 mission. Photo: NASA TV

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Astronauts perform first spacewalk

STS-126 mission specialists Heide Stefanyshyn-Piper, KD5TVR, and Steve Bowen worked outside the station Tuesday for the first of the mission's four spacewalks.

Their tasks included the replacement of a nitrogen tank assembly, assorted station assembly tasks, and the start of cleaning and lubrication of the starboard solar alpha rotary joint.

Inside the station, STS-126 mission specialist Don Pettit, KD5MDT and Expedition 18 flight engineer Sandra Magnus, KE5FYE operated the station's robotic arm, and mission specialist Shane Kimbrough, KE5HOD served as the intravehicular officer, or spacewalk coordinator.

The spacewalk began at 1:09 p.m. EST and ended at 8:01 p.m.