English: Astronauts Rick Mastracchio and Canadian Space Agency's Dave Williams (out of frame), both STS-118 mission specialists, participate in the mission's first planned session of extravehicular activity (EVA), as construction continues on the International Space Station. During the 6-hour, 17-minute spacewalk Mastracchio and Williams attached the Starboard 5 (S5) segment of the station's truss, retracted the forward heat-rejecting radiator from the station's Port 6 (P6) truss, and performed several get-ahead tasks.