Astronauts Complete Overnight Spacewalk

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NASA's COLBERT Treadmill

A pair of astronauts from the space shuttle Discovery changed out a 1,300 pound holding tank from the International Space Station during a six and a half hour spacewalk that began Tuesday night and ended Wednesday morning.

Astronauts Danny Olivas and Nicole Stott removed the bulky ammonia tank from the ISS and will replace it with a new module during a follow-up spacewalk later in the week.

While Olivas and Stott worked out in space, station crewmembers were busy transferring 7.5 tons of cargo, including an exercise device named after comedian Stephen Colbert, from Discovery to the ISS.

In addition to the COLBERT treadmill, the payload from Discovery's Leonardo Multi-Purpose Logistics Module also includes two research racks, a new ISS station crew quarters, the Minus Eighty-Degree Laboratory Freezer and an Air Revitalization System Rack for the space station.

Discovery successfully docked with the ISS late Sunday, paving the way for an exchange of crew members. Stott traded places with ISS flight engineer Tim Kopra, who spent the past 44 days aboard the space station. Stott is now formally part of the ISS Expedition 20 crew, while Kopra will join the Discovery team for a ride back to Earth.

Earlier Sunday, shuttle commander Rick Sturckow steered Discovery over the ISS by performing the "rendezvous pitch maneuver," a nine-minute backflip that allows space station crews to photograph Discovery's underbelly. The digital photos were downloaded to NASA controllers so they could inspect the condition of Discovery's heat shields.

Discovery launched in the pre-dawn hours Saturday morning from the Kennedy Space Center in Florida. NASA aborted several previous attempts due to weather and mechanical issues.

STS-128, as the mission is called, is under the command of shuttle veteran Sturckow. Joining him are six other space goers, including pilot Kevin Ford and mission specialists Patrick Forester, Jose Hernandez, and John Olivas. Christer Fuglesang will represent his native Sweden on the mission.

Discovery crew members are slated to perform three space walks during the mission. The shuttle is expected to return to the Kennedy Space Center on Sept. 10.