- Associated Press - Tuesday, July 12, 2011

CAPE CANAVERAL, FLA. (AP) - Astronauts making the last spacewalk of NASA’s space shuttle era on Tuesday retrieved a broken pump from the International Space Station and installed a fill-er-up experiment for a robot.

The space station’s two-armed robot Dextre won’t tackle the $22.6 million playset _ a fancy Fisher-Price toy as one astronaut describes it _ until long after Atlantis departs and the shuttle program ends.

But perhaps more than anything else on this final journey by a shuttle, the robotic demo illustrates the possibilities ahead for NASA: satellite-refueling stations in space run by robots.

In a departure from previous shuttle visits, the spacewalking job fell to space station astronauts, Michael Fossum and Ronald Garan Jr., who teamed up for three spacewalks in 2008. The four-person Atlantis crew is the smallest in decades, and so the lone spacewalk of the mission was handed over to the full-time station residents.

It was the 160th spacewalk in the 12 1/2-year life of the orbiting outpost, and the last one planned for Americans for more than a year.

“To see that we’ve really done it, it’s just awe-inspiring,” Fossum said of the completed space station and all the spacewalks that went into it. “Ron and I are honored to be a part of it, to help close out one of the final chapters.”

Fossum and Garan completed the two major chores _ the pump removal and robotic test hookup _ inside of 3 1/2 hours. They spent the rest of the 6 1/2-hour spacewalk on a variety of small tasks.

The two paused during their spacewalk to admire the view 245 miles below _ Kennedy Space Center _ and on the next swing around the world, Houston, home to Mission Control.

“Hello Kennedy, beautiful launch,” Fossum called out. Atlantis departed Kennedy on Friday on the very last shuttle launch.

The ammonia coolant pump stopped working last July and, for more than two weeks, left the space station with only half its cooling capability. Space station residents had to perform three emergency spacewalks last summer to replace the pump and restore full cooling to all the on-board equipment.

NASA wants the pump brought back to Earth so engineers can figure out why it failed to help them keep the on-board station pumps running. The space station is intended to operate until at least 2020.

Garan gripped the pump as the space station’s robot arm maneuvered him over to Atlantis. The pump was anchored in the shuttle’s payload bay, ready for next week’s ride home. A small object ended up floating away, possibly a fabric strap from some insulation.

As they turned their attention to the robotic experiment, the spacewalkers thanked all the thousands of people who worked on the shuttle. “It is really beautiful,” Garan said.

Flight controllers choked up as Garan wrapped up work in the shuttle payload bay and noted that he was leaving it for the last time _ the last time by anyone.

“We’re technical people and we keep our heads in the game in real time,” said Mission Control’s Glenda Brown, the lead spacewalk officer, “but there wasn’t any one of us who didn’t have a little bit of a catch in our throat.”

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