The candidates are now going through medical checkups and a final list will be presented to Russian space authorities shortly, Space Adventures spokesman Sergei Kostenko told AFP.

Rosaviokosmos, the Russian space agency, had earlier said that it planned to take two more space tourists to the ISS in 2004-2005 despite some concern about the lucrative program from the United States.

Russia has tasked Space Adventures with finding the fit -- and rich -- candidates for the trips.

The asking price for a 10-day visit to the ISS is around 20 million dollars (17.2 million euros), a sum only two space tourists -- Californian businessman Dennis Tito and South Africa Internet millionaire Mark Shuttleworth -- have been able to pay so far.

Trips scheduled by US boy band star Lance Bass from 'N Sync and former NASA official Lori Garver was called off after they were unable to pay.

Russia and the United States, the ISS's major partners, have clashed over Moscow's keenness to raise money for its cash-strapped space program by selling tourist tickets to the ISS.

In February, Russia announced the temporary suspension of space tourist flights after the US shuttle Columbia disintegrated on its way back to earth from the ISS.

The tragedy forced the United States to rely completely on Russian craft to ferry crew and supplies to the ISS.

SPACE.WIRE