By Paul Rincon
BBC News Online science staff
The news that Sir Richard Branson has signed a deal to take paying passengers into space suggests the Ansari X-Prize has achieved its goal of bringing space tourism closer to the masses.
The first space vehicle will be called VSS-Enterprise
One of the aims behind the $10m (£5.7m) challenge was to galvanise enthusiasm for private manned spaceflight, thereby bringing "out of this world" tourism within reach of ordinary people.
In the past, space travel has been open only to the privileged few; either government-back astronauts or millionaires with enough spare cash to book a flight on a Russian Soyuz rocket to the International Space Station.
If and when the Virgin venture - dubbed Virgin Galactic - begins offering its first spaceflights, the tickets will still be expensive. A sub-orbital flight is expected initially to cost about £100,000.
But Sir Richard says prices will eventually come down to a level where "masses of people" will get to enjoy the space experience.
Five Virgin Galactic SpaceShips are to be built. They will carry five passengers in luxury seats. Anyone who buys a ticket will require about a week's worth of flight training for what will be just a three-hour trip.
Virgin Galactic's fleet will be based on the technology developed by aviation legend Burt Rutan for SpaceShipOne, the Ansari X-Prize contender which made history in June as the first private manned craft to travel 100km (62 miles) above Earth - the official boundary of space.
THE ANSARI X-PRIZE
Rewards the first team to send a three-person craft over 100km (62 miles)
Contenders must then repeat the feat in the same carrier inside two weeks
A total of 24 teams are vying for the prize
The prize is worth $10m (£5.7m)
The teams must be privately-backed and not linked to government organisations
That flight proved to the world that there was nothing fanciful or far-fetched about private individuals making their own space vehicles.
"[The Ansari X-Prize] has succeeded in doing what it set out to do. The original idea was to break the mould of thinking - to break [the US space agency's] monopoly on space policy," David Ashford, director of Bristol Spaceplanes Limited - a British rival to SpaceShipOne for the X-Prize - told BBC News Online.
"Space tourism should have happened years ago."
Short but sweet
Jeffrey Lenorovitz, a spokesperson for the Orbital Recovery Group, which aims to build a so-called "space tug" to rescue malfunctioning satellites commented: "The idea is to crush the mindset that government has to be involved, because industry and entrepreneurs have and will respond."
Sir Richard says research suggests there are about 3,000 people around the world who would be willing to sign up to the initial wave of flights with Virgin Galactic.
THE VIRGIN SPACESHIP
The vehicle will have room for five passengers
A week's pre-flight training will be required
Three-hour trip; three minutes of weightlessness
Flights to leave from Mojave Desert, initially
Tickets to cost about £100,000, perhaps less
"It will enable people to go into space, to become astronauts, to see the Earth, to enjoy weightlessness," Sir Richard told the BBC.
"Eventually, we want to get prices down to levels where masses of people can enjoy space."
The Virgin SpaceShips will be sub-orbital vehicles, like SpaceShipOne. Sub-orbital flights break through the atmosphere before falling back to Earth. They give passengers only a few minutes of time in true space.
These vehicles do not have the velocity to enter into orbit around our planet. So, although SpaceShipOne has proven that getting into space is easy, staying there may prove to be harder.
Konrad Dannenberg, an original member of the German rocket team that kickstarted America's space programme after WWII told BBC News Online recently: "[Burt Rutan] eventually wants to take well-paying passengers into space and to let them see from up there what it looks like down here.
"But he is not in Earth orbit. To get into Earth orbit is still a pretty large, pretty major step. I have heard Rutan has plans to do that eventually. I am really looking forward to hearing what he wants to do."
Some believe that space tourism will only enter into its own when orbital flights are offered.
"The real market, the big market, is going into orbit. SpaceShipOne goes sub-orbital - it goes up and comes down; you get three minutes of weightlessness," says David Ashford.
"That's great but what you really want is to go into orbit so you can spend a few days in space. I think Rutan's success has triggered a race for orbital spaceflight - and we can still win that race.
"You don't need new technologies to go to orbit. To make a prototype, to make it economic and practical to carry people - that's where the development has to go."
Orbital craft are also needed if Sir Richard's future plans for a space hotel are to be realised.
Jeffrey Lenorovitz formerly worked for MirCorp which several years ago worked up a proposal for a private-access space station. However, the idea did not receive the necessary backing from international space agencies and investors.
"I still believe that for an orbital space station with private access, there will be a capability. Just imagine if there was a space station that had a regular means to get up there," Mr Lenorovitz told BBC News Online.
"I know scientists who have spent 10 years developing a payload and have waited 15 years to get it up into space. There's something wrong with that formula if indeed space is going to be used to its best capability."
Of course, there are inevitable safety issues involved; space travel - as history has shown - can be a dangerous business. But many feel that, if regulated properly, the inherent risk involved in flying into space need not be much greater than that involved in flying on commercial aircraft.
"Airlines need to follow regulations and standards, and there is no reason why this should not be applied to space travel as well," says Mr Lenorovitz.
"For me, [this venture] is the next logical step to get the engineers, the diners and the dreamers together with someone who knows how to market transportation for various classes of people.
"It's a step towards taking access to space out of the hands of the chosen few."