Russia's Rosaviakosmos space agency is proposing together with US firm Space Adventures for couples to fly together to the International Space Station (ISS) on a Russian Soyuz space craft, said Rosaviakosmos spokesman Sergei Gorbunov.

"Under our contract with Space Adventures we have an option for sending two space tourists at once on a Soyuz. So theoretically, young married couples could make use of this possibility," he told the ITAR-TASS news agency.

The asking price for a 10-day visit to the ISS is around 20 million dollars (16 million euros), a sum only two space tourists -- Californian businessman Dennis Tito and South Africa Internet millionaire Mark Shuttleworth -- have so far been willing to pay.

Both tourists jaunts were organised by Space Adventures. The price for a couple would be twice that amount.

Candidates, who would travel on board one spaceship accompanied by a professional astronaut, would have to show they are in a good health and undergo eight to 10 months of training, the official said.

In addition, "they will have to prove they don't have bad habits, money from illegal sources and don't belong to any terrorist organisation," Gorbunov added.

The Russian space official did not specify whether sex would be permitted for the space-bound honeymooners.

Astronauts are banned from having sex in space because of the possible risks to the embryo if a female cosmonaut became pregnant.

In August this year, Russian cosmonaut Yury Malenchenko, 41, married 27-year-old Yekaterina Dmitriyeva in space, although the bride remained firmly on the earth while he was aboard the orbiting space station.

Malenchenko went ahead with the wedding despite the opposition of his superiors at Rosaviakosmos, who saw the union as a potential breach of security and stressed that in future "space marriages will be forbidden".

Space Adventues, the Arlington, Virgina-based firm, which brokered the first two tourist space flights in 2001 and 2002, has signed a contract with Rosaviakosmos to fly two more tourists to the ISS in 2004-2005.

Russia and the United States, the major partners in the 16-nation ISS project, have clashed in the past over Moscow's keenness to raise money for its cash-strapped space program by selling tourist tickets to the ISS.

Russia sends Soyuz rockets to the ISS every six months on so-called "taxi missions".

SPACE.WIRE