NASA Astronauts Wrap Up Final Spacewalk of the Atlantis Mission to the International Space Station

Two spacewalking NASA astronauts from the shuttle Atlantis fastened a bulky oxygen supply tank and a science experiment to the outside of the International Space Station on Monday, after their near six-hour outing got off to a late start.

The spacewalk by Robert Satcher and Randy Bresnik was the third and final outing assigned by NASA to the Atlantis astronauts. The shuttle fliers plan to depart the station on Wednesday, following a productive week-long work session with the five American, Russian, Canadian and European astronauts living aboard the orbiting science lab.

"Great job," Mike Foreman, the Atlantis astronaut who coordinated the excursion from inside the space station told his colleagues. "You've done everything we have asked and more."

Though Monday's spacewalk began an hour late in order to correct a problem with the drinking water bag in Satcher's space suit, the two men quickly made up for lost time as they worked their way through a list of tasks.

"I don't know how it could be going any better," Atlantis commander Charlie Hobaugh said of the flight's progress.

During their stay, the Atlantis astronauts have dropped off nearly 30,000 pounds of spare parts and other hardware intended to keep the space station operating well beyond the shuttle's scheduled retirement by mid- 2011. The station could receive a reprieve from its own scheduled retirement in 2016.

The Obama Administration is considering an extension of station activities until 2020, a move favored by NASA's 14 international partners in the project that makes the current shuttle visit all the more crucial.

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During Monday's outing, Satcher and Bresnik hoisted and fastened a bulky oxygen tank atop the station's airlock with the help of a robot arm. The tank, which was among the spare parts delivered by Atlantis, will be used to replenish the air that is lost each time spacewalking astronauts depart and re-enter the station.

Most of the spares, including a pair of gyroscopes and an assortment of thermal control system and robot arm components, were too large for delivery by other spacecraft.

The spacewalkers also installed a materials science experiment delivered by Atlantis.
The experiment holds dozens of samples of materials under consideration for use in the production of future space gear.

The samples include candidate materials for a space suit that could be worn by astronauts as they explore the moon as well as for the solar panels on NASA's Orion crew exploration vehicle. They will be monitored as they are weathered by the hard vacuum of space, drastic temperature swings, solar radiation and other corrosive forces.

The Atlantis crew plans to spend Thanksgiving in orbit preparing their spacecraft to return to Earth on Friday.

Though Atlantis began its 11-day mission with six astronauts, it will return to the Kennedy Space Center in Florida with seven fliers.

The new passenger is astronaut Nicole Stott, who is ending a three-month tour of duty aboard the space station.