Astronauts Plan Fix for Serious Space Station Leak

Critical cooling system leaks ammonia

Astronauts aboard the international space station are preparing for a possible spacewalk Saturday to try to repair a leak in a critical cooling system. It's clearly a serious problem for the crew going around the Earth 16 times a day, but the astronauts hardly sound panicked.

"Good Morning, Earth! Big change in plans, spacewalk tomorrow, Chris Cassidy and Tom Marshburn are getting suits and airlock ready. Cool!" Cmdr. Chris Hadfield (@Cmdr_Hadfield) of the Canadian Space Agency tweeted Friday morning.

"The whole team is ticking like clockwork, readying for tomorrow. I am so proud to be Commander of this crew. Such great, capable, fun people," he added.

Thursday was supposed to be a rare "light-duty day" for the space station crew — a chance for the Russians on board to mark a national holiday, Victory Day, and also allow three astronauts, including Hadfield, to pack their personal items in anticipation of a return to Earth on Monday. But the astronauts saw small, white flakes drifting away from the station — "a very steady stream of flakes, or bits," Hadfield told mission controllers in Houston.