US astronaut Michael Fincke and Russian cosmonaut Gennady Padalka opened the hatch at 1:19 am Moscow time (2119 GMT Wednesday) and stepped out of the station, a spokesman for TsUP mission control told AFP.

Fincke and Padalka had briefly left the orbiting station on Friday but had to come back in after a few minutes because of a defect in Fincke's space suit.

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 the 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.

SPACE.WIRE