CAPE CANAVERAL, Fla. - Space station astronaut Rick Mastracchio may get his Christmas wish for a spacewalk or two because of a broken cooling system.
One of two space station cooling loops shut down Wednesday. Flight controllers suspect a bad valve inside a pump. On Friday, engineers in Houston spent the third straight day trying to solve the problem.
The cooling system uses ammonia to dispel heat generated by on-board equipment. The six astronauts have turned off non-essential equipment to reduce the heat load, including many experiments.