CAPE CANAVERAL, Fla. — A pair of space station astronauts had to hammer loose a stuck connector Saturday during an urgent spacewalk to restore a crucial cooling system, and they ran out of time before they could remove a broken pump.
Douglas Wheelock and Tracy Caldwell Dyson went into the spacewalk hoping to replace the ammonia coolant pump with a spare at the international space station. But they were forced to leave the failed pump in place.
What’s more, a fair amount of ammonia leaked out, forcing them to set aside time to get any traces of the toxic substance off their spacesuits.
NASA originally estimated two spacewalks would be needed to replace the failed pump. After the trouble Saturday, managers say three will be necessary. The next spacewalk won’t be attempted until Wednesday at the earliest. Engineers need to figure out the next step.
Halfway through their lengthy spacewalk, Wheelock and Caldwell Dyson could not get one of the four pressurized ammonia hoses to come off the disabled pump.
“Wow. That thing is not budging,” Wheelock told Mission Control.
Caldwell Dyson floated by his side, unable to offer much assistance because of the tight quarters. They were so close that their helmets kept bumping against each other.
Lagging well behind by this point, the spacewalkers managed to remove three of the four hoses. Wheelock tried once more to disconnect the balky line, banging the jammed button with a special tool. It worked.
Mission Control erupted in applause. “Awesome,” Mission Control radioed up.
But the exuberance was dampened by the escaping ammonia.
At eight hours, NASA said it was the sixth-longest spacewalk ever.
The ammonia pump shut down last weekend and knocked out half of the space station’s cooling system.
The pump is supposed to push ammonia coolant through the lines on the right side of the complex and prevent equipment from overheating. To cope with the failure, the six-person crew had to turn off all unnecessary equipment.
NASA said the breakdown is serious but has not endangered the crew, and the one functional cooling loop has kept the space station stable.
Information
Saturday’s spacewalk was the first by Americans without a shuttle present since 2008.
The space-station crew includes three Americans and three Russians.
