International Space Station: Inside the Moments After Astronauts Evacuated

PHOTO: The International Space Station is seen in this April 20, 2014 file photo made from a frame grabbed from NASA-TV.PlayNASA-TV/AP Photo
WATCH Mission Control to ISS Astronaut: 'Enjoy Your Impromptu Day Off'

Moments after an alarm sounded in the American section of the International Space Station, signaling a possible gas leak, the astronauts showed remarkable calm as they evacuated to the Russian area of the station.

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Speaking to ground control, Commander Butch Wilmore said the team had powered down non-essential equipment and was working to find out what prompted the early morning alarm.

Astronauts first feared there had been an ammonia leak, however NASA said in a briefing this morning that it was a false alarm, likely triggered by a sensor.

Overnight, Mission Control at NASA's Johnson Space Center in Houston saw an increase in cabin pressure, which in a worst-case scenario, can be indicative of an ammonia leak, according to NASA.

Samantha Cristoforetti, an Italian astronaut who is on her first mission at the International Space Station, tweeted that the group was doing well and spending the day in the Russian segment.

It's not immediately known how long the astronauts will have to bunk in the Russian segment of the station, however Astronaut James Kelly at Mission Control gave them one piece of advice:

"Enjoy your impromptu day off."