"The cosmonauts are now loading software into the station's computer," said a spokesperson from mission control in Moscow. "It underwent tests after being rebooted earlier and it looks like everything is working fine."

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

Cosmonauts worked round the clock

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

Nasa was worried that the problem would hamper the launch of the American shuttle craft Discovery, which is due to rendezvous with Mir on Tuesday.

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

Discovery to pick up Thomas

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

The countdown continues at Cape Canaveral

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.