ISS crew to return to US sector: no ammonia detected

Early this morning, a potential ammonia leak on the International Space Station forced a trio of astronauts to move from the US segment of the ISS into the Russian segment, sealing off the US segment in the process until further data could be collected. An alarm had been triggered that could have indicated an ammonia leak, and in addition the ISS's protection software proceeded to shut down one of a pair of redundant cooling loops. Fortunately, all has ended well.

The incident took place around 3AM central time this morning, and now appears to be resolved, with NASA saying in a statement that the astronauts have been told they can return the US segment tonight. An ammonia leak was never detected despite the alarm indicating it was a possibility.

The space agency stresses none of the crew were ever in danger, and that they're all in "good condition". Flight controllers had spent the day studying the data produced by the ISS's various systems, and it is ultimately suspected a transient error message is the cause of the alarm.

A relay box was turned off and then back on to clear the error message, and all is well again. Still, the crew will be returning to the US segment while wearing protective gear they put on before entering the Russian side. They will perform some tests to further ensure there is no ammonia present before removing the gear and getting back to regular business.