The U.S. section of the International Space Station had to be evacuated this week after a possible ammonia leak prompted alarms to sound.
Florida Today reported that the alarm sounded around 4 a.m. Wednesday. It's sometimes indicative of an ammonia leak, leading the crew to put on masks and to conceal themselves in the Russian segment of the space station. But it could also be the result of a faulty sensor, officials said.
"Flight controllers in Mission Control at NASA's Johnson Space Center in Houston saw an increase in pressure in the station's water loop for thermal control system B then later saw a cabin pressure increase that could be indicative of an ammonia leak in the worst case scenario,"
NASA said in a statement at 7:48 a.m. Wednesday.
"Spacecraft communicator James Kelly said flight controllers were analyzing their data but said it is not yet known if the alarm was actually triggered by a leak or whether the situation was caused by a faulty sensor or by a problem in a computer relay box that sends data and commands to various systems on the station," NASA's statement continued.
At 8:55 a.m., NASA received a second update from the ISS crew.
"The crew received an update from spacecraft communicator James Kelly that it's starting to look like a false indication, either a faulty sensor or computer relay," the NASA blog stated. "Flight controllers are continuing to analyze the situation but for now, there is still no direct evidence that ammonia was leaked into the station atmosphere."
The crew, though, remained isolated in the Russian segment of the International Space Station in the meantime.
The Verge.com reported that Canadian astronaut and former ISS crew member Chris Hadfield posted on Twitter that a leaking coolant system is just one of the emergencies astronauts are trained for.