The space flight director, Vladimir Solovyov, told the Russian news agency Interfax that Mir was now working as normal.

Cosmonauts worked round the clock

But earlier, officials at the American space agency Nasa said the computer problems aboard Mir were still not fully resolved - just a day before the American space shuttle, Discovery, was due to take off for a rendezvous with the space station.

A Nasa spokesman said the cosmonauts found that there was still a problem when they tried to reactivate other systems.

The computer broke down on Saturday, leaving the station adrift in orbit but in no immediate danger.

Although a replacement computer was installed on Sunday, Mir cosmonauts were unable to get it working properly because of a problem when downloading software.

The American shuttle cannot dock with Mir unless the station's automatic steering system is working and keeping the space station steady. Steering is controlled by the computer.

Thomas going home?

The countdown may be back on hold

The shuttle is due to take home Andrew Thomas - the last of seven American astronauts to serve on Mir.

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.

Mir replacement delayed

Meanwhile, 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.