CAPE CANAVERAL — A pair of space station astronauts had to hammer loose a stuck connector during an urgent space walk to restore a crucial cooling system Saturday, then an ammonia leak erupted and hampered the entire repair effort.
Despite making one of the longest space walks ever, Douglas Wheelock and Tracy Caldwell Dyson had to give up trying to remove a broken ammonia pump and retreat inside.
Disappointed managers said two more space walks now will be needed to replace the pump and get the International Space Station's cooling system operating normally again. The original plan called for two space walks.
Another space walk won't be attempted until Wednesday at the earliest. Engineers huddled following Saturday's eight-hour, three-minute effort — the sixth-longest space walk ever — to consider their options.
"We will get through this problem," said space station program manager Mike Suffredini. "The challenge is to get through this problem before the next problem hits the other cooling system."
The pump failure knocked out half of the space station's cooling system last weekend, leaving the orbiting lab with only one good cooling loop. Another breakdown could leave the station in a precarious situation.