A pair of spacewalking astronauts floated back outside Saturday night to hook up plumbing on the newest room of the International Space Station and bring it alive with power. Robert Behnken and Nicholas Patrick had to route extra-long hoses that were fashioned right before space shuttle Endeavour's trip to the space station. The original ammonia coolant lines failed tests, and so engineers had to put together replacement hoses from shorter spares that were welded together. The hoses are 14 feet (4.3 meters) to 18 feet (5.5 meters) long and, along with a protective blanket, cumbersome to work with. Once ammonia coolant is flowing through the hoses, Tranquility will begin surging with power. Its systems cannot be turned on unless there is a way to get rid of the heat generated by the equipment inside. Endeavour is now scheduled to return to Earth on Feb. 21.
