Watch the progress and problems experienced during a three-year collaboration between Russia and the US

Officials at the American space agency, Nasa, said the flight was scheduled to go ahead despite an earlier computer failure on board Mir which had put the mission in jeopardy.

Discovery is due to take off for Mir on Tuesday night

Discovery is scheduled to blast off on Tuesday night on Nasa's ninth and final shuttle hookup with Mir. The shuttle will bring home Andrew Thomas, the last of seven American astronauts to live on the ageing Russian outpost.

The acting director of Russia's Mir-shuttle programme, Boris Sotnikov, said: "The situation is basically under control, and there is no reason to delay."

Nasa said it would continue to monitor the station's steering system and its computer, which failed over the weekend. But space agency officials stressed they were confident with the repairs.

Frank Culbertson, director of Nasa's shuttle-Mir programme, said: "It's interesting that at the very end of the programme, after such a smooth increment for Andy, that we had this problem occur with the motion-control system.

"It's frustrating to a certain extent, but, hey, maybe it's our signature. It certainly adds some drama to it."

The computer broke down on Saturday, leaving the station adrift in orbit but in no immediate danger. It was replaced by the three-man crew on Sunday, but the new computer also shut down because of an electronic fault.

The computer controls Mir's automatic steering system, which is needed to keep the space station steady when the shuttle docks with it. Until it was fixed, Nasa had been debating whether to delay the shuttle launch.

End of an era

Cosmonauts worked round the clock

Andrew Thomas has been living on Mir for the past four months and said last week that he is "very keen" to come home.

If Discovery lifts off shortly around 2200 GMT on Tuesday as planned, it will link up with Mir on Thursday and have Thomas back on Earth on June 12.

The American mission will be the last before the space station is taken out of service at the end of June.

It will mark the end of more than three years of collaboration between Russia and the US onboard Mir.

Replacement delayed

Nasa officials say the assembly of a new space station to replace Mir will be delayed to the end of the year.

The first part of the International Space Station was to have been launched this month - but that has now been put back to November because Russia has fallen behind in building the space station's first module.

Tight financial constraints on the Russian space programme have been blamed for the delay.