An alarm in a U.S. segment of the International Space Station prompted part of its crew to quickly lock up and move to a Russian module early Wednesday morning. The crew is not in danger, and NASA says it hasn't confirmed what prompted the alarm.
The alarm that went off around 4 a.m. EST can sometimes be indicative of an apparent ammonia leak. However, there is currently no "concrete data" that suggests an ammonia leak, NASA says.
As the team at mission control in Houston pores over the data, the agency said it seems to point to a sensor or a computer relay issue rather than a leak. NASA told Mashable that it will have a statement soon.
The Expedition 42 crew currently stationed in the U.S. segment donned masks when they moved to the Russian segment of the station, and the crew was directed to isolate themselves in the Russian station as a precaution. Power to the module is being rebooted now as flight controllers try to figure out what happened.
For now, the six-person crew is all together in the same module, where there is enough food and provisions for at least a week, according to mission control in Houston.
While it now looks unlikely, if this does turn out to be an ammonia leak, it wouldn't be the first time on board the space station. Last March astronauts discovered an ammonia leak in a coolant system attached to one of the station's solar arrays, threatening power on board the ISS. NASA and its station partners first noticed a leak in that same loop system in 2007, but the amount of ammonia releasing was so low at the time that no action was required.
The space outpost is currently manned by NASA astronauts Barry Wilmore and Terry Virts, Russians Elena Serova, Alexander Samoukutyaev and Anton Shkaplerov and European Space Agency astronaut Samantha Cristoforetti.