A pair of astronauts installed a new ammonia pump on the International Space Station during a spacewalk today, in just the second Christmas Eve spacewalk in NASA's history, the AP reports. "It's like Christmas morning opening up a little present here," astronaut Rick Mastracchio said as he opened his toolkit, Later, as he pulled the 780-pound, refrigerator-sized pump from its storage shelf, he said, "Now it really feels like I'm unwrapping a present."
The spacewalk should fix the station's damaged cooling system—the old ammonia pump, which was pulled out during a Saturday walk, had developed a bad valve. The festive timing almost didn't happen; the walk was scheduled for yesterday, but astronaut Mike Hopkins accidentally hit a water switch in the airlock while coming back from Saturday's spacewalk, getting water into his suit and rendering it unusable for a week. Mission Control also considered holding the entire project off until January, but decided that the station was too vulnerable to wait.