Olsen was to pay 20 million dollars for the flight in April 2005 to the International Space Station (ISS) onboard a Russian Soyuz rocket under an agreement with US firm Space Adventures.

"Under the accord, Space Adventures can propose to us the candidacy of another tourist, who will begin preparing for the flight in the spring of 2005," Russian Space Agency chief Anatoly Perminov told ITAR-TASS.

"Most likely, a second Russian cosmonaut will take the vacated seat" for the mission in April next year, Perminov said, adding that this would be decided in late June.

A spokesman for the space agency, Konstantin Kreidenko, would not comment on the decision to bar Olsen but told AFP: "If he has problems with his health, his chances of making the flight have been destroyed."

Olsen, a technology millionaire, has been training in the Star City astronaut training centre outside Moscow under a contract that ends in June.

Soyuz space craft have three places, two of which must be occupied by a Russian and US astronaut.

Space Adventures also organised the first space trips for paying customers: American businessman Dennis Tito in 2001 and South African Mark Shuttleworth in 2002. They also went on Russian rockets for a 20-million-dollar price tag.

SPACE.WIRE