Two spacewalking astronauts made repairs to a leaky radiator system outside the International Space Station Thursday, a short while after maneuvering the station to avoid a menacing piece of space debris.

In a six-hour procedure, space station commander Sunita Wiliams and Japanese astronaut Akihiko Hoshide successfully reconfigured ammonia coolant lines to bypass the suspect radiator, which may have been hit by space debris months earlier. A bank of radiators dissipate heat from the station's electronic equipment.

Engineers say the tiny leak is equivalent to a human hair in diameter, and that controllers in the coming days will measure coolant content to see if the problem has been corrected.

As preparations began Wednesday for the space walk, the station was forced to maneuver to avoid a piece of space wreckage from the 2009 collision of two satellites. Engineers fired thrusters on a docked Russian supply ship to move the orbiting laboratory out of harm's way.