A grapefruit-sized space debris orbiting at 21,000 miles per hour missed hitting the International Space Station (ISS) Wednesday and aborted an evacuation by its three astronauts, the U.S. space agency said.

The object measuring five inches in diameter is part of an old rocket motor of a U.S. Navy global positioning system satellite and was detected by the space junk-tracking U.S. Strategic Command (STATCOM) late Wednesday.

STRATCOM warned NASA that the object, which has been orbiting since 1993, might collide with the ISS at 12:39 EDT. There was no time to maneuver the ISS to a safe position so NASA told astronauts Mike Fincke and Sandra Magnus, and cosmonaut Yury Lonchakov at 11:40 a.m. to board a Russian spacecraft attached to the space station so they can escape in case of a collision.

The three stayed inside the Soyuz spacecraft for 11 minutes before they were cleared to return to the station.

STRATCOM failed to detect how close the object passed the ISS because of its small size, NASA spokesman Kelly Humphries said, according to Washingtonpost.com.