CAPE CANAVERAL, Fla. (AP) - Two of the shuttle astronauts have spent the morning outside the International Space Station, beginning the three-step process of swapping-out an ammonia tank.
Ammonia is used for the space station's cooling system. The shuttle Discovery brought up a fresh tank.
Astronaut Clayton Anderson had no problem taking apart the ammonia lines on the old tank. But he needed a pry bar to get the new one out of Discovery's payload bay. He and astronaut Rick Mastracchio put the tanks in temporary positions until they can return to the work Sunday. It will take three spacewalks to finish the job.
Besides the tank work this morning, the two astronauts collected a science experiment from the space station's Japanese lab, and replaced a failed station-positioning device.