Astronauts on the International Space Station (ISS) had to move from the station’s American section to the Russian section on Wednesday after a suspected ammonia leak, NASA and the Russian Federal Space Agency said.
Flight controllers saw an increase in pressure in the station’s water loop, followed by a cabin pressure increase “that could be indicative of an ammonia leak in the worst case scenario,” NASA said in a statement.
US astronauts Barry Wilmore and Terry Virts were directed to the Russian segment while the situation was being evaluated.
NASA said that it is not yet known if the alarm was actually triggered by a leak. It could have also been a faulty sensor or a problem in a computer relay box, it said.
Russia’s Federal Space Agency said that the US astronauts will remain in the Russian segment until Thursday. “There is enough oxygen and food,” the agency’s Oleg Ostapenko said according to Russian news agencies.
Currently the ISS is staffed with three Russians, two Americans and one female Italian astronaut.
Ammonia is used as a coolant on the station. A leak of the highly toxic substance is seen as a common risk situation and the crew train for this as a standard safety measure, German astronaut Alexander Gerst told dpa. Gerst spent six months on the ISS in 2014.