Space Station Leak Repaired in Emergency Spacewalk

Astronauts had to undertake a rapidly planned emergency spacewalk this Saturday to fix a serious ammonia leak at the International Space Station that was discovered just two days earlier. NASA announced that the repair was apparently successful, but only the next few weeks will show if there is no new leakage. Authorities also said the space station's six-member crew was not in danger from the leak.

"I will tell you that we're happy. We're very happy," Joel Montalbano, NASA's deputy space station program manager, said Saturday. "We didn't see any obvious signs of a leak, but it's going to take some time ... for us to look at the system, evaluate the system and make sure we did, indeed, stop the leak."

Expedition 35 Flight Engineers Chris Cassidy and Tom Marshburn completed a 5-hour, 30-minute spacewalk at 2:14 p.m. EDT Saturday to inspect and replace a pump controller box on the International Space Station’s far port truss (P6) leaking ammonia coolant.

A little more than 2 1/2 hours into the spacewalk, Cassidy and Marshburn removed the 120 kilogram pump controller box from the P6 truss and replaced it with a spare that had been stowed nearby on the port-side truss, or backbone of the station. Mission Control ran the new pump while the spacewalkers watched for any ammonia snowflakes, but so far there have been no new signs of a leak.

The P6 truss was launched to the station as the oldest component of the station’s backbone aboard the shuttle Endeavour on the STS-97 mission in November 2000. This weekend's repair spacewalk was already the 168th in support of the assembly and maintenance of the space station and the third for both Cassidy and Marshburn.

The spacewalk was also hurried because the experienced astronaut Marshburn will descend back to Earth on Monday, which will officially mark the end of Expedition 35 and the start of Expedition 36. The undocking of the Soyuz TMA-07M spacecraft is set for 7:08 p.m. EDT Monday, carrying Chris Hadfield, Marshburn and Flight Engineer Roman Romanenko back to Earth, with a scheduled landing 3 hours later in southern Kazakhstan, wrapping up 146 days in space for the trio.

In preparation of their departure, Expedition 35 Commander Chris Hadfield ceremonially handed command of the station over to Expedition 36 Commander Pavel Vinogradov on Sunday.