Image above: The STS-118 and Expedition 15 crews greet each other after hatch opening. Image: NASA TV

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Power transfer system activated

The STS-118 and Expedition 15 crews are conducting joint operations aboard Space Shuttle Endeavour and the International Space Station. The crew also activated the Station-to-Shuttle Power Transfer System (SSPTS) at 5:17 p.m. EDT Friday.

These activities began within hours of STS-118’s arrival at the space station. Endeavour docked with the station at 2:02 p.m. and the STS-118 was welcomed aboard the station at 4:04 p.m.

The SSPTS is designed to reroute power from the station to a visiting shuttle. If the transfer system works as expected, mission managers could elect to extend STS-118’s mission from 11 to 14 days and increase the number of spacewalks from three to four. A decision on a possible extension could occur Sunday.

Astronaut Richard A. (Rick) Mastracchio, KC5ZTE

The two crews are preparing for STS-118's first spacewalk, which is set to begin at 12:31 p.m. Saturday. The spacewalkers will assist in the installation and activation of the Starboard 5 (S5) truss.

Friday’s preparations included transfer of spacewalk equipment and the review of procedures. Also, the two crews used the shuttle robot arm to lift the S5 out of the payload bay and hand it off to the station robotic arm.

The two spacewalkers, Mission Specialists Rick Mastracchio, KC5ZTE, and Dave Williams, will enter the station’s Quest airlock where they will spend the night. This procedure is performed to help prevent decompression sickness.