From: Johnson Space Center
Posted: Friday, July 24, 2009
Mission Control Center, Houston, Texas
HOUSTON - Mission specialists Chris Cassidy and Tom Marshburn finished replacing batteries on the International Space Station's oldest solar arrays during a seven-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. That completed the work with all 12 new and old batteries, which was begun on the mission's third spacewalk by Cassidy and Mission Specialist Dave Wolf. Higher than expected carbon dioxide levels in Cassidy's suit limited that spacewalk's duration, so the remaining battery tasks were deferred until today.
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 at 5:52 p.m. for return home.
This was the fourth of five STS-127 spacewalks, the 129th in support of International Space Station assembly and maintenance, totaling 805 hours, 42 minutes. It was the 101st spacewalk conducted out of space station airlocks and the 217th American spacewalk in history. It was the second for Cassidy and Marshburn.
The mission's final planned spacewalk is Monday, performed by Marshburn and Cassidy together again to work on various tasks around the outside of the station.
The station crew is scheduled to begin its sleep period about 7 p.m., followed 30 minutes by the shuttle crew. Mission Control's musical wake up is scheduled for 3:33 a.m. Saturday.
The next mission status report will be issued after crew wake, or earlier if warranted.
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