CAPE CANAVERAL, Fla. ------ Spacewalking astronauts worked on the outside of Japan's shiny new science lab Thursday, installing cameras and removing covers. Dressed head to toe in white, Michael Fossum and Ronald Garan jr. looked like puffy dolls against the 37 foot long, 14 foot wide lab, which 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. " I feel like I'm on a camping trip trying to pack up a wet tent on a Sunday morning," Fossum said as he wrestled with some of the lab's insulation. He and Garan removed thermal covers from the lab's robot arm and added them to a variety of attachment points.

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 of the racks moving in, Kibo still was 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.

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 robotic arm. The two TV cameras that were set up on the lab's exterior will be instrumental in those robot arm operations.

One last spacewalk is planned to replace an empty nitrogen gas tank at the space station.