Nikolai Budarin and his US crewmates Kenneth Bowersox and Donald Pettit, who had blasted off from the International Space Station on the Soyuz TMA-1 earlier Sunday, were to have landed at 6:07 am Moscow time (0207 GMT).

However, with the capsule landing some 440 kilometres (275 miles) away from the preset destination, it was more than two hours before rescue teams could locate the spacecraft and its crew, officials told AFP in the Kazakh capital.

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

A rescue airplane finally got into visual contact with the capsule at 8:21 Moscow time (0421 GMT), allowing the search teams the precise location of the crew.

Meanwhile, the astronauts had managed to open the hatch and get out of the vessel an hour and a half after the landing, officials said, adding that two helicopters were dispatched to the site to retrieve the crew.

The helicopters were expected to get to the landing spot in the Kazakh steppe, 230 kilometres southeast of the city of Aktyubinsk, by 10:20 Moscow time (0620 GMT). The crew was then to fly to the Russian cosmodrome of Baikonur in Kazakhstan and onto Moscow the same day.

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.

Anxiety was high ahead of the first landing on Earth since the Columbia accident. Bowersox and Pettit were also the first US astronauts to come back from space in a Soyuz.

The only American until then to return to Earth in a Russian spacecraft had been Dennis Tito, a US millionaire who became the world's first "space tourist" two years ago when he went to the ISS and back on a Soyuz.

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

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

SPACE.WIRE