Officials at the American space agency, NASA, say final preparations are under way for the launch of the space shuttle Discovery for a rendezvous with the Russian space station, Mir.

The flight is scheduled to go ahead later today despite an earlier computer failure on board Mir which had put the mission in jeopardy.

The faulty computer, which controls Mir's automatic steering system, was replaced by the three-man crew on Sunday.

But the new computer also shut down because of an electronic fault.

It will be the shuttle's final mission to Mir before the space station is taken out of service.