Supplies arrive for space station astronauts

The space station's future is in doubt

A Russian cargo ship has arrived at the International Space Station (ISS) carrying food and fuel to the three-man crew.

The unmanned vessel was also carrying scientific equipment, medical supplies and letters for the two American astronauts and one Russian cosmonaut on board the ISS.

The crew have been on the platform since November and were due to return home in March.

But US shuttles have been grounded indefinitely following the Columbia shuttle disaster.

Vladimir Solovyov, the head of Russian ground control, said on Tuesday that the ISS crew would have to stay until at least April or mid-May, when Russia plans to launch its next manned flight.

Russian role

The Progress supply ship, which was launched from Kazakhstan on Sunday despite Saturday's disaster above Texas, would boost the crew's food and water supplies until June, officials said.

"They have completed the docking procedure. Everything has gone successfully," a Russian spokeswoman said.

With the US shuttle fleet grounded, concerns have been raised about the future of the ISS.

US shuttles usually carry long-term crews to and from the ISS, and lift aloft the large segments needed to extend the platform. Russian Soyuz capsules have tended to carry up only short-visit crews.

If necessary, the current ISS crew could come down to Earth aboard a Soyuz "lifeboat" vehicle that is attached to the platform and reserved for emergencies.

However, US and Russian space agencies are reluctant to leave the space station unmanned.