Briton poised for space trek after colleague falls ill

As troubles on the Mir space station go from bad to worse, there is now a real possibility that the British astronaut Michael Foale (right) will be asked to embark on a hazardous repair mission into a module damaged in last month's crash with a cargo ship.

Russian officials have asked Nasa whether it will allow the 40-year-old astrophysicist to take the place on the mission of Mir's commander, Vasily Tsibliyev, who has been complaining of heart problems, tiredness, and overwork.

The switch would mean a significant change of plan; during the operation, Dr Foale was to have manned a Soyuz escape capsule, which will be ready to launch an emergency getaway. However, Nasa said that he was fully trained to stand in for the Russian cosmonaut. "If it's necessary, we can do this," said a spokesman.

The sortie, which was yesterday postponed for up to 10 days because of the Russian's ailment, requires two of the crew to enter the dark, airless, freezing and cramped Spektr module, which was punctured during the collision, the worst accident in Mir's 11-year history.

The crew has been preparing for the space trek by studying mock-ups at mission control, but their task is further complicated by uncertainty over what may be floating around inside Spektr, whose contents include laboratory equipment. There has been concern that chemicals may have escaped from their containers and may damage the cosmonauts' equipment.