The first Virgin vehicle will be called VSS-Enterprise

There are already 13,500 potential passengers for the �100,000 ($190,000) "Virgin Galactic spaceliner" trip, Sir Richard told the BBC.

The entrepreneur is having five "spaceliners" built in the US by the team which launched the SpaceShipOne rocket plane last year.

Sir Richard said he himself, his children and his parents all plan to be on the first flight.

The Virgin Atlantic airline boss told the BBC's Breakfast with Frost the space travel plan "is an extremely exciting project".

He signed a �14m agreement last September with Mojave Ventures, the company set up by Microsoft co-founder Paul Allen and aviation pioneer Burton Rutan.

They can experience weightlessness, they will check out that the Earth is round and enjoy space Sir Richard Branson

Mojave Ventures plans to use the technology developed for SpaceShipOne - the first privately-developed carrier to go above 100km last June.

Virgin Galactic passengers will have three to four days' training in Virgin's "space camp" in the Mojave Desert in the south-western US, Sir Richard said. He said passengers will go up in the mother ship 'Eve' which will launch the space craft at three times the speed of sound.

He described the unique things passengers would experience during a three-and-half-hour trip.

"They can experience weightlessness, they will check out that the Earth is round and enjoy space," he said.

THE VIRGIN SPACESHIP The vehicle will have room for at least five passengers A week's pre-flight training will be required Three-hour trip; several minutes of weightlessness Flights to leave from Mojave Desert, initially Tickets to cost about $200,000, perhaps less

"Then the spacecraft turns into a giant shuttlecock which makes the entry safe and then once it comes back into the Earth's atmosphere it turns back into a space craft which glides down".

Sir Richard said it was this change in the shape of the aircraft that greatly increased safety.

"The big difference between our space ship and a Nasa space ship is that Nasa has to contend with the massive heat build-up as it enters the Earth's atmosphere."

He said the Galactic flight would not face this heat build-up, and this made it "many times safer" than a Nasa space ship.

However, he added: "We are pioneering and there are obviously risks attached if you are pioneering anything new".

Sir Richard, well-known for his speedboat and ballooning adventures, said that he planned to be on the first flight himself.

He said his children Holly and Sam and his parents were also interested in being on it. But, he added, his wife Joan was not keen on the idea of going into space.