A pair of astronauts ventured out on the last spacewalk of NASA's space shuttle era Tuesday to retrieve a broken pump from the International Space Station and install 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 nearly a year.