On July 24, 2009 astronauts C.Cassidy and T.Marshburn finished replacing batteries on the International Space Station’s oldest solar arrays during a 7-hour, 12-minute spacewalk – the fourth of five planned during space shuttle Endeavour’s STS-127 mission.
They installed four of six new batteries for the P6 Truss structure, where a pair of solar array wings collects sunlight for power generation. They stored four more of the old batteries onto a cargo carrier for return to Earth.
Inside the complex, Tim Kopra choreographed the activities. Mission specialists Koichi Wakata and Julie Payette used Canadarm2 – the station’s robotic arm – to hand the Integrated Cargo Carrier with the old batteries to the shuttle’s arm. Pilot Doug Hurley and Commander Mark Polansky then secured the carrier in Endeavour’s cargo bay for return home.
This was the fourth of five STS-127 spacewalks, the 129th in support of International Space Station assembly and maintenance. It was the 217th American spacewalk in history. It was the second for Cassidy and Marshburn.