Initially, this might simply involve introducing a delay in communications to controllers in Moscow and Houston, US. Ultimately, it could also involve removing crew members into separate modules to give them a taste of what the Mars500 participants have gone through.

BBC: Simulated Mars mission 'lands' back on Earth

In order to determine the location of the leak, the crew had been sealing off small peripheral modules of the space station while Mission Control looked for accelerated pressure drops inside the sealed-off sections.

MSN: Crew finds ��culprit�� in space station leak