Live coverage: Three Chinese astronauts return to Earth

Two NASA astronauts and an Italian flight engineer took shelter in the space station’s Russian segment Wednesday as mission control analyzed a possible leak of toxic ammonia coolant aboard the complex. Initial data indicated it was likely a false alarm.

Russian commander Oleg Kononenko, Canadian co-pilot David Saint-Jacques and NASA flight engineer Anne McClain closed out a 204-day mission in orbit Monday with an undocking from the International Space Station at 7:25 p.m. EDT (2325 GMT), followed by landing in Kazakhstan aboard their Soyuz MS-11 capsule at 10:47 p.m. EDT (0247 GMT Tuesday).

Kirk Shireman, NASA’s program manager for the International Space Station, is retiring from the space agency later this month to take a position in private industry.