MacLean and Williams work at the Robotic Arm in the U.S. Laboratory during STS-115 EVA

View of Astronauts Steve MacLean, Canadian Space Agency (CSA), Mission Specialist (MS), and Jeffrey N. Williams, Expedition 13 Flight Engineer (FE) and NASA Space Station Science Officer working at the Space Stations Robotic Arm to slowly move the 17 and a half ton P3/P4 truss to the port side of the Integrated Truss System. They will align it using a television camera and then mate it to the P1. Photo was taken in the U.S. Laboratory/Destiny during Expedition 13 / STS-115 joint operations.