CAPE CANAVERAL — Spacewalking astronauts worked on the outside of Japan's new science lab Thursday, installing cameras and removing covers.
Michael Fossum and Ronald Garan Jr. removed thermal covers from the lab's robot arm and added them to a variety of attachment points. The 37-foot-long, 14-foot-wide lab is now the biggest room at the international space station.
It was their second spacewalk in three days at the shuttle-station complex, orbiting 210 miles above Earth.
As the spacewalkers toiled outside, their eight colleagues hauled more experiment racks into the billion-dollar lab, called Kibo, Japanese for hope, and flight controllers near Tokyo monitored the power systems.
Even with all the racks moving in, Kibo was still noticeably bigger than the eight other rooms at the space station.
Space shuttle Discovery's astronauts delivered and installed Kibo earlier in the week. There are now three labs at the orbiting complex, supplied by NASA, the European Space Agency and, now, the Japanese Space Agency.
Today, the astronauts will attach a storage shed to Kibo that was dropped off by another shuttle crew in March. And on Saturday, they will test drive Kibo's 33-foot robot arm.
One last spacewalk is planned for Sunday, to replace an empty nitrogen-gas tank at the space station. Fossum and Garan got a head start on that work Thursday.
Some of their chores ended up being downright strenuous. As the spacewalk hit the five-hour mark, the two joked that they would skip the workout at the gym and eat whatever they wanted for dinner.