Chris Hadfield: ISS ammonia leak 'a very steady stream'
10 May 2013 Last updated at 12:14 BST
International Space Station Commander Chris Hadfield has described a "very steady stream" of ammonia flakes leaking from the platform's cooling system.
The seepage is coming from the port side, at the far end of the structure that holds one of the laboratory's huge sets of solar arrays.
Nasa says the crew is in no danger. A spacewalk might be needed to inspect and fix the site of the leak.
Liquid ammonia is used to extract the heat that builds up in electronic systems, dumping that excess energy to space through an array of radiators.