The ceremony was to be an out-of-this-world affair with the 41-year-old groom orbiting the Earth at a height of some 240 miles (400 kilometres) and his bride, 26, firmly earthbound in an auditorium in her home city of Houston, Texas.

Malenchenko, who will be hurtling through space at some 17,500 miles (28,000 kilometres) an hour as he ties the knot, is proceeding with the wedding despite the initial opposition of his Russian Space Agencysuperiors, who saw the union as a potential breach of security.

His American colleague aboard the International Space Station (ISS), Ed Lu, will be best man, while a family friend will stand in for the groom during the ceremony in Texas, according to US media.

Under Texas law, a marriage can go ahead if one of the parties is absent for valid reasons. US officials have accepted a space mission as one such reason.

The event has been planned well in advance, with the couple receiving a marriage licence last month from a Texas court and the wedding ring having been delivered to the space platform aboard a Progress cargo vessel that refueled the ISS in June.

A tailcoat was also delivered by the supply vessel to enable the groom to dress in style for what US reports say will be a televised ceremony.

According to a Russian source, Dmitriyeva has negotiated with a US television station for it to broadcast the ceremony live. She was expected to speak to the media at around 2:00 pm local time (1900 GMT).

The television deal would provide a handsome windfall for the couple who would not even have to pay the cost of the transmission -- between 8,000 and 10,000 dollars (7,100 to 8,800 euros) for 10 minutes -- as cosmonauts are allowed to speak with their loved ones for free while in orbit, an RSA official said.

RSA spokesman Sergei Gorbunov meanwhile said that he had no objection to the marriage.

"Marriage is a cosmonaut's own business," he told the ITAR-TASS news agency. "Actions by cosmonauts in orbit are regulated by the inter-governmental Code of Cosmonauts' Conduct on Board the ISS which contains no direct ban on marriages."

However Moscow gave its assent through clenched teeth, officials having opposing the marriage for as long as they could on that grounds that Malenchenko, as an active-duty officer in Russia's armed forces, was party to confidential information.

Gorbunov stressed that in future "space marriages will be forbidden" and said that henceforth this would be made explicit in cosmonauts' contracts.

Any contacts between Malenchenko and Dmitriyeva would have to take place "during the statutory time allocated for contacts between the crew and their relatives," he said.

On Friday Gorbunov warned that Malenchenko would face some stiff questioning from his superiors when he returned from space, although "he won't be thrown into prison for this."

A spokesman for Russia's space mission control centre in Moscow was similarly tight-lipped.

"It's got nothing to do with us," he said of the wedding on Moscow Echo radio. "We're not paying for it, I've no idea who is."

Malenchenko, who is divorced, proposed to Dmitriyeva in December before blasting off for the ISS in April. Dmitriyeva is a US citizen who emigrated from the Soviet Union with her parents when she was four.

They plan to marry in a church in Russia when Malenchenko returns to Earth in October, then spend their honeymoon in Australia.

SPACE.WIRE