NASA: leak no danger to crew at International Space Station

The International Space Station has sprung a leak.

Ammonia - which is used to cool its power system - is seeping out.

The station's commander said that the situation is serious - but NASA insists there is no danger to the crew.

Space expert Doctor Andrew Coates explains what may be behind it:

"A meteor impact could cause a whole," said space expert Doctor Andrew Coates.

"The other possibility is that the space station like all other things in low earth orbit go round the earth once every 90 minutes so it goes from day to light during that time and so the thermal stresses are huge on any components like pipes and so on."