The three astronauts took refuge for 11 minutes Thursday in a Russian escape capsule before returning inside. Officials were worried that the space station might get hit with a piece of space junk.

NASA says the debris was a small piece of an old spacecraft motor and it was passing within three miles of the station.

The piece measured less than an inch but tiny pieces of debris could cause a fatal loss of air pressure in the station. NASA says it isn't the first time they've sent the station crew into the capsule for safety.

There are two Americans and one Russian aboard the space station.
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