Image above: Mission Specialist Rick Mastracchio participates in the first spacewalk of the STS-118 mission. Image: NASA TV

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Spacewalkers add S5 truss to space station

Mission Specialist Rick Mastracchio, KC5ZTE, and Dave Williams wrapped up STS-118’s first spacewalk at 6:45 p.m.

During the 6-hour and 17-minute excursion, they successfully installed the Starboard 5 (S5) truss segment onto the International Space Station and continued preparations to relocate the Port 6 (P6) truss.

With Mastracchio and Williams assisting, Pilot Charles Hobaugh used the station’s robotic arm to attach the S5 at about 1:35 p.m. The spacewalker then went to work to permanently bolt the S5 in place on the end of the Starboard 4 truss segment and then performed some scheduled and get-ahead tasks to prepare the S5 for the arrival of the Starboard 6 truss next year.

The final major objective of the spacewalk was the retraction of a radiator on the Port 6 (P6) truss. After the radiator was folded, Mastracchio and Williams secured it. The P6 will be relocated from atop the station to the end of the Port 5 truss during a future shuttle mission.

The spacewalk began at 12:28 p.m. and was the first conducted for Williams and Mastracchio. STS-118 Mission Specialist Tracy Caldwell coordinated spacewalk activities, and Expedition 15 Flight Engineer Clay Anderson, KD5PLA, assisted Hobaugh at the controls of the station’s Canadian-built robotic arm. Two more spacewalks are currently scheduled for STS-118.

The Station-to-Shuttle Power Transfer System, which was activated after Friday’s docking, was shut down as a precaution during the spacewalk. It will be brought back online later today. The transfer system may allow Space Shuttle Endeavour and the STS-118 crew to stay at the station longer.

A decision on a possible mission extension to 14 days is expected to be made Sunday.