The second STS-115 spacewalk is now in the history books. STS-115 Mission Specialists Dan Burbank and Steve MacLean concluded the spacewalk at 12:16 p.m. EDT after continued efforts to prepare the International Space Station’s P3/P4 truss for operation.
The 17.5-ton, 45-foot truss, which contains a set of solar arrays, was attached to the station Tuesday. The P3/P4 will provide power, data and communication services for the station. The arrays will be unfurled to a full length of 240 feet Thursday and will eventually double the station’s power capabilities.
Burbank and MacLean began their excursion at 5:05 a.m. and proceeded to move through the scheduled activities, which included the removal of launch locks and launch restraints on the Solar Alpha Rotary Joint (SARJ). Once activated, the rotary joint will allow the arrays to track the sun.
About 7:10 a.m. EDT, MacLean reported that one of the four bolts on the cover of the SARJ launch lock 8 was missing. The bolt had been there when he removed the cover to access the lock. MacLean reported he did not see the bolt in the SARJ mechanism. The cover is secure with three of the four bolts in place.
Later, the socket being used by MacLean to loosen a stubborn bolt on launch restraint 6B broke. MacLean retrieved a cheater bar from the tool box on the Z1 Truss. He broke the torque, but ultimately it took both he and Burbank to remove the bolt and launch restraint.
During the remainder of the spacewalk, the astronauts were instructed to perform get-ahead tasks. They prepared the P3 truss for use by the Mobile Transporter – a platform that allows the station’s robotic arm, Canadarm2, to move along the Integrated Truss Structure.
Mission Specialist Joe Tanner served as spacewalk coordinator. Mission Specialist Heidemarie Stefanyshyn-Piper assisted Tanner and operated Canadarm2. Tanner and Piper conducted the first spacewalk and will perform the third Friday.
Explore further: Spacewalkers Preparing New Truss for Operation