International Space Station crew evacuates US section due to 'leak'

http://www.theguardian.com/science/2015/jan/14/iss-space-crew-evacuate-leak

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The crew on board the International Space Station have been forced to evacuate and seal off the US part of the station after an alarm sounded for a potentially hazardous chemical leak.

Two Americans and an Italian astronaut have taken refuge with three cosmonauts in the Russian section of the station after a sensor detected a possible ammonia leak from a cooling system.

The Russian space agency, Roscosmos, said all six of the international crew had evacuated to the Russian part of the station in line with emergency procedures after the alarm sounded about 9am GMT on Wednesday.

On hearing the alarm, the crew donned masks and moved to the Russian section as a precautionary measure. Nasa emphasised that a faulty sensor or computer system may well have triggered a false alarm.

“There is no hard data to suggest there was a real ammonia leak,” a Nasa spokesman said. “The crew members are safe and in good shape inside the Russian segment of the International Space Station.

As analysts pored over data coming back from the International Space Station, the alarm looked ever more likely to have been caused by a faulty sensor. “It’s becoming a stronger case this is a false indication,” the spokesman added.

The cooling system on the space station uses two loops that are filled with ammonia. The ammonia collects heat from electronic equipment on board and is then pumped outside the station where it dumps the heat into space through giant radiators.

The alarm sounded after a sensor detected a change in pressure in part of an associated water cooling system and a buildup in the station’s cabin pressure, which can be a sign of an ammonia leak. As the astronauts sealed off the US section of the station and made for cover, Nasa controllers switched off non-essential equipment and began an investigation.

The crew is expected to remain in the Russian segment for the rest of the day until analysts are sure that the US segment is safe to open again. In a discussion with the US astronauts, Nasa’s capcom in Houston, Jim Kelly, told the isolated crew: “There’s nothing for you to do now. Enjoy your impromptu day off.”

Maxim Matyushin, head of the Russian mission control centre in Moscow, said in a Roscosmos statement: “The crew’s safety has been achieved through the coordinated and expedient actions of the cosmonauts and astronauts, as well as the mission control teams in Moscow and in Houston.”