The rocket will seek to equal its feat of June 21 when it touched the fringes of space, 100 kilometers (60 miles) up, before making what its creator Burt Rutan admitted had been a scary return to its base in California's Mojave desert.

But Rutan's mission to bring space travel to the general public has already been boosted by a tie-up with British tycoon Richard Branson.

A specially adapted jet, White Knight, will take SpaceShipOne up into the sky at 6:00 am (1300 GMT) on Wednesday.

At 48,000 feet (15 kilometers) the vessel will be released and its pilot will start the rocket engine to take it back up to the edge of space.

If the flight is a success, Rutan's spacecraft will make a new flight one week later on October 4 to qualify for the Ansari X Prize.

The 10 million dollar prize is offered by a private US-based foundation. The winner must send the same manned vessel into space twice in two weeks. It must carry the pilot and the equivalent weight of two passengers.

The Ansari foundation launched the prize eight years ago to give the same impetus to space travel that the Orteig prize did to inspire Charles Lindbergh's first transatlantic flight in 1927.

Rutan, 61, set up his own company Scaled Composites to form the Mojave Aerospace Ventures team, build SpaceShipOne and further the cause of private enterprise in space.

There are 26 teams in contention for the Ansari prize but SpaceShipOne believes it is the leader, according to Sarah Evans, a spokeswoman for the Ansari X Prize foundation in St Louis, Missouri.

"The other teams have not given notice that they will fly," she said.

A Canadian team, Da Vinci, which has linked up with the world's biggest online gambling website, goldenpalace.com, plans to launch a manned rocket attached to a balloon at 90,000 feet (27,000 metres). The return to Earth would be with the help of a parachute.

The Canadians had planned a trial run on October 2 but postponed it.

Rutan told the Houston Chronicle newspaper in a recent interview, "the main reason we did this project was to show that a small company not working with government dollars, can actually fly a manned space flight."

He expects SpaceShipOne to attract a lot of investment to the sector and that in "a few years" people will be able to buy tickets for suborbital flights.

Branson, who founded the Virgin airline, announced Monday that he had signed a 14 million pound (25 million dollar) accord with Mojave Aerospace Ventures to set up Virgin Galactic, the first company to offer trips into space for the general public.

The project will use technology based on SpaceShipOne and Branson has predicted the first flights could take place in three years.

The Aviationweek magazine said in its latest edition that a US businessman, Robert Bigelow, has offered a 50 million dollar prize for the building of a private launcher that can take five-to-seven astronauts into space by the end of the decade.

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