However, helicopters have so far been unable to locate the spacecraft and its crew after the return module landed 30 kilometres (20 miles) away from the preset destination, officials said.

The astronauts nevertheless managed to make radio contact with the rescue teams and assure them that they were fine before communications broke off, rescue officials said, adding that the radio signal was too weak for the search party to use it to pinpoint the vessel.

Bowersox, Pettit and Budarin had been aboard the ISS since December. They were originally to have left in March, but their return to Earth was delayed because of the Columbia space shuttle disaster.

Columbia disintegrated during re-entry to the Earth's atmosphere on February 1, killing all seven crew members and leading NASA to suspend all shuttle missions, including those to the ISS.

Russian flight commander Yury Malenchenko and US flight engineer Edward Lu, who travelled aboard Soyuz to the space station are due to stay aboard the ISS for six months.

Russian spacecraft currently provide the only transportation to the space station.

SPACE.WIRE