Stock Photo - Astronaut Heidemarie Stefanyshyn-Piper, STS-126 mission specialist, participates in the mission's first session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the six-hour, 52-minute spacewalk, Piper and astronaut Steve Bowen (out of frame), mission specialist, worked to clean and lubricate part of the station's starboard Solar Alpha Rotary Joints (SARJ) and to remove two of SARJ's 12 trundle bearing assemblies. The spacewalkers also removed a depleted nitrogen tank from a stowage platform on the outside of the complex and moved it into Endeavour's cargo bay. They also moved a flex hose rotary coupler from the shuttle to the station stowage platform, as well as removing some insulation blankets from the common berthing mechanism on the Kibo laboratory.