Expedition Five's Peggy Whitson and Atlantis' Sandy Magnus used the station's Canadarm2 robotic arm to grapple the 45-foot-long, 14-ton S1 structure, remove it from Atlantis' cargo bay and move it to the starboard end of S0. Motorized bolts locked the two truss segments together at 8:36 a.m. CDT.
Wolf and Sellers ventured outside the station's Quest airlock at 10:21 a.m. Their first task was to connect power, data and fluid lines between the S0 and the S1 trusses. As Wolf worked to accomplish this task, Sellers, on his first spacewalk, released the locks on three folded-up radiators mounted to the S1, allowing S1's radiators to be oriented for optimal cooling
Wolf and Sellers then worked together to install a new S-band antenna assembly. Wolf, attached to the end of the station robotic arm, moved the antenna into position. He then tightened stanchion bolts to lock the antenna into place near the end of the S1 Truss where it connects to the S0 as Sellers held it in place. The new component will increase the S-band data and voice communications capability from the space station to ground controllers.
The duo then went to work releasing restraints that had held the Crew and Equipment Translation Aid (CETA) cart to the S1 for launch and configure its brakes. The CETA cart, a handcar that rides along rails on the station's truss, can be used to move spacewalkers and equipment.
Installation of the S1's outboard nadir external camera was the final major task of the spacewalk. The camera, launched on Atlantis' middeck, is the first of two that will be installed on S1. They will be used as situational awareness tools for spacewalkers and robotic arm operators.
Throughout the spacewalk, Pilot Pam Melroy was inside, offering guidance and advice to the spacewalkers and keeping them on schedule. She had help with arm operations and spacewalk guidance from controllers in the International Space Station Flight Control Room because the spacewalk originated out of the station's Quest airlock. Shuttle Commander Jeff Ashby operated the shuttle robotic arm, providing camera views for documentation.
Following an inventory of the tools they used during the spacewalk and cleanup activities, Wolf and Sellers re-entered Quest. Airlock repressurization began at 5:22 p.m., signaling the end of the spacewalk.