Astronaut Doug Wheelock, STS-120 mission specialist, participated in the third scheduled session of extravehicular activity (EVA) as construction continued on the International Space Station (ISS). During a 7-hour and 8-minute space walk, Wheelock and mission specialist Scott Parazynski (out of frame), installed the P6 truss segment with its set of solar arrays to its permanent home, installed a spare main bus switching unit on a stowage platform, and performed a few get-ahead tasks.