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.

The 58-foot robot arm had both of its aging mechanical hands replaced on previous spacewalks. Friday's work involves bringing one of those old hands inside so it can be returned to Earth for a tuneup, and moving the other gripper to a long-term storage location outside.

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.