S115-E-05781 (13 Sept. 2006) --- Astronauts Daniel C. Burbank (left) and Steven G. MacLean, representing the Canadian Space Agency, participate in the second of three scheduled space walks for the Space Shuttle Atlantis and International Space Station crewmembers as construction resumes on the space station. The two STS-115 mission specialists are working at part of the integrated truss system. MacLean is flanked by two breadbox-sized equipment bags.