CAPE CANAVERAL, Fla. — Two astronauts worked on a leaky radiator system outside the International Space Station on Thursday, hours after dodging orbiting junk.

NASA ordered the space station to change position Wednesday to avoid a fragment from a communication satellite. Space station commander Sunita Williams and Japanese astronaut Akihiko Hoshide rerouted ammonia coolant lines and bypassed a radiator thought to be leaking.