(CNN) -- Discovery astronauts Steve Bowen and Alvin Drew are scheduled for a six-hour spacewalk outside the international space station Monday.
The team prepared by holding a 14-hour "campout" in the station's Quest airlock.
"The airlock's atmospheric pressure will be lowered to help purge nitrogen from Bowen and Drew's bloodstreams, protecting them from 'the bends' when they leave the airlock for the vacuum of space," a statement on NASA's website said.
They will install a power extension cable, move a failed ammonia pump and perform other operations outside the shuttle during the spacewalk.
Discovery started its 39th and final flight with a launch late Thursday afternoon from Kennedy Space Center in Florida. CNN
