Spacewalking astronauts stepped out Friday to wrap up months of repair work on the International Space Station's big robot arm. NASA astronaut Mark Vande Hei and Japan's Norishige Kanai emerged from the orbiting complex as the sun rose over Peru's western coast, 250 miles below. The 58-foot robot arm had both of its aging mechanical hands replaced on spacewalks conducted in October and January. Friday's work involved bringing one of those old hands inside so it can be returned to Earth for a tuneup and then flown back up, and moving the other gripper to a long-term storage location outside. This last spacewalk in the series should have been completed by now, but was postponed because of complications with the robotic hand that was installed last month. Further delays were caused by this week's late arrival of a Russian supply ship.

Mission Control noticed his red tether seemed frayed and worn and ordered Acaba to "remain put" with his good waist tether locked to the structure as Bresnik went to get him a spare. Spacewalking astronauts always have more than one of these crucial lifelines in case one breaks. They also wear a jetpack in case all tethers fail and they need to fly back to the space station.

Spacewalking astronauts worked at giving the International Space Station's big robot arm a new hand Thursday. Commander Randy Bresnik and Mark Vande Hei tackled the job on the first of three NASA spacewalks planned over the next two weeks. It needs to be replaced before an Orbital ATK supply ship launches in November. Spacewalking astronauts worked at giving the International Space Station's big robot arm a new hand Thursday. The Deep Space Gateway will orbit Earth and the moon and will open up opportunities for future exploration of deep space, as well as a return to the moon and missions to Mars.