NASA has ordered up a series of urgent space walks to fix a broken cooling line at the International Space Station, a massive repair job that could stretch to Christmas Day.
Station managers decided Tuesday to send two American astronauts out as soon as possible to replace a pump with a bad valve. The task will require two and possibly three space walks on Saturday, Monday and next Wednesday — Christmas Day.
"The next week will be busy with space walks so not much tweeting from here," NASA astronaut Rick Mastracchio said from space via Twitter soon after the decision was announced.
Half of the space station's cooling system shut down Dec. 11, forcing the six-man crew to turn off all nonessential equipment, including some science experiments. While the astronauts are safe and comfortable, NASA wants the system back up to full strength, in case of another failure that could leave the orbiting outpost even more vulnerable than it is right now.
Flight controllers tried to fix the bad valve remotely, then came up with a plan to use another valve to regulate the temperature. Some success was reported, and for a while, engineers thought the space station could limp along with the short-term solution. But on Tuesday, managers opted for space walks.
NASA hopes to wrap up the pump swap in two space walks and not have to do a third on Christmas Day. Astronauts have ventured outside of their spaceship on Dec. 25 only once, way back in 1973 during Skylab, America's first space station.
U.S.-led space walks have been on hold since July, when an Italian astronaut almost drowned because of water that leaked into his helmet.