Astronauts Take NASA's Last Spacewalk of Shuttle Era

Astronauts making the last spacewalk of NASA's space shuttle era today retrieved a broken pump from the International Space Station and installed a fill-er-up experiment for a robot on the side of the space station. The two-armed robot Dextre won't actually begin the $22.6 million experiment until long after Atlantis departs, 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.

Dextre, a hulking metal robot with 11-foot arms, will release locks on the tools in August but won't try out the workbench until January. The designers of the experiment envision robots one day using these methods to fill the fuel tanks of satellites orbiting as high as 22,300 miles. That would keep the spacecraft operating longer, instead of becoming expensive pieces of space junk. What's more, spacecraft bound for distant worlds could fill up after launch, thereby flying more payloads because of the savings in fuel weight. (More Michael Fossum stories.)