Discovery Astronauts Suit Up For Spacewalk Outside Station

Discovery astronauts Rick Mastracchio and Clayton Anderson are suiting up in the U.S. Quest airlock at the International Space Station, preparing to heading outside the outpost early Sunday on an excursion aimed at performing some maintenance work on its cooling system.

The shuttle astronauts woke up around 9:21 a.m. to the soothing sounds of Ella Fitzgerald's "Stairway To The Stars," a song played for mission specialist Stephanie Wilson, prime robot arm operator on the Discovery crew. She thanked her parent's for asking NASA to beam up the tune.

Mastracchio and Anderson camped out overnight in the Quest airlock, where the atmospheric pressure was reduced to rid their bodies of nitrogen gas that could cause decompression sickness in the vacuum environment in low Earth orbit. The astronauts remain on scheduled for airlock egress at 2:16 a.m. Sunday.

The second of three spacewalks planned during Discovery's stay at the station will be devoted to swapping out a spent ammonia coolant tank. It will be the 142nd spacewalk performed in the assembly and maintenance of the station, the first two building blocks of which were linked in low Earth orbit in December 1998.