US astronauts in last space walk of shuttle era

CAPE CANAVERAL: Two US astronauts stepped out on the last spacewalk of the shuttle era Tuesday at the International Space Station, where Atlantis is docked on the final mission of the 30-year US program.

Americans Ron Garan and Mike Fossum floated out of the airlock at 9:22 am (1322 GMT) for the six and a half hour spacewalk, aimed at retrieving a failed ammonia pump from the orbiting lab and moving it to the shuttle's payload bay for return to Earth.

The duo, who were already aboard the ISS when Atlantis arrived on Sunday as part of the six-member international Expedition 28 crew, will also attach a Robotic Refueling Module experiment to the lab.

The joint US-Canadian project aims to test technologies for repairing and refueling satellites in space.

Atlantis's crew of four American astronauts will help support the spacewalk. (AFP)