Washington -- Two NASA astronauts failed to remove a broken cooling pump from outside the International Space Station after a frustrating eight-hour effort Saturday that set the record as the longest spacewalk at the floating observatory.

The unsuccessful attempt left engineers scrambling to come up with a new repair plan for the 780-pound cooling pump that helps keep the station from overheating. It broke after a power surge a week ago, so the station is being cooled by one pump instead of two.
For now, the six-member crew is in no danger and station operations are continuing with little disruption. But if the remaining pump fails, the crew would be forced to cut power to much of the station and rely on the Russian section, which runs on a different power and cooling system, to handle critical tasks.
The plan going into Saturday's spacewalk was for astronauts Doug Wheelock and Tracy Caldwell Dyson to remove the broken pump and install a spare. But they were unable to completely disconnect the old pump because of a leak in one of the ammonia lines.
With the old pump still in place, NASA will have to change its plans to check the electrical and ammonia line connections to the new pump on a spacewalk Wednesday.
(Source: latimes.com)