Flight controllers fired thrusters on the space station Tuesday morning. That moved the orbiting lab and its crew of six safely away from a chunk of an old NASA research satellite.
The debris originally was projected to come within one-tenth of a mile of the space station. The latest estimate put the close approach at a half-mile. Because of the uncertainty, NASA elected to move the space station.
In a statement, NASA said that there had been a "green" probability of a collision, meaning the debris would have posed no threat. The agency noted that six previous tracking readings had consistently showed a "red" probability and so the astronauts decided o proceed with the maneuver and the burn was executed.
Increasingly, space is being filled up with space junk. NASA estimates there are more than 500,000 pieces of debris in orbit around the Earth, traveling at speeds up to 17,500 mph.
NASA says the space station relocation will have no significant impact on next Monday's launch of the space shuttle Discovery. Discovery launched the atmospheric research satellite in 1991.