Walheim during EVA 2

S122-E-008149 (13 Feb. 2008) --- Anchored to a foot restraint on the station's robotic Canadarm2, astronaut Rex Walheim, STS-122 mission specialist, transfers a large nitrogen tank assembly -- used for pressurizing the station's ammonia cooling system -- during the second scheduled session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station.