A fire scare hit astronauts aboard the International Space Station today just as they were trying to get some sleep. Smoke alarms were triggered on the orbiting outpost, 230 miles above the Earth.

Commander Gennady Padalka spotted fumes coming from a water-processing unit in a Russian wing of the station, the Zvezda Service Module.

He immediately shut off power to the machine which recycles water for the spacemen to use and the smoke swiftly cleared.

NASA said the crew of six were not in any danger and did not need to don breathing masks or take any further protective measures. The incident would have no impact on the mission and there was alternative water-processing equipment in a US module.

The agency said alarm bells rang on the station about an hour after the crew had been due to start their scheduled sleep period, although they were still awake at the time.

NASA’s shuttle Endeavour was due to blast off from Florida later today on a mission delayed from last month that will deliver another seven astronauts to the space station. It is a mission that will carry the 500th person ever to fly in space. But shuttle commander Mark Polansky revealed via Twitter that his flight was off again. NASA said they wanted to evaluate earlier lightning strikes close to the launch pad and hope to launch tomorrow.

Picture: The International Space Station in orbit. (NASA).

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