US astronaut Michael Fincke and Russian cosmonaut Gennady Padalka stepped out of the ISS at 01:57 am (21:57 GMT Thursday) for a repair mission scheduled to last six hours, a spokesman for Russian Mission control, Valery Lyndin, was quoted by the ITAR-TASS news agency as saying.

However, the two men came back into the ISS after only a few minutes, due to a defect in the oxygen supply system of Owen's space suit, flight director Vladimir Solovyov told ITAR-TASS.

"The pressure in Owen's oxygen cylinder started to fall sharply, so we decided to interrupt the space walk and ordered the astronauts to return to the station," Solovyov said.

Fincke and Padalka were scheduled to repair one of four gyroscopes controlling the station's orientation as it orbits Earth, replacing a circuit breaker that failed and cut power from the gyroscope.

The space walk was originally scheduled for June 16, but it was delayed to avoid possible communication problems resulting from the launch of a satellite from Russia. No date for a new space walk has yet been specified.

SPACE.WIRE