SpaceShipOne: one flight down and one to go. Credit: © Scaled composites

SpaceShipOne powered into space from the California desert early on Wednesday morning, completing the first half of designer Burt Rutan's bid to win the coveted Ansari X prize.

To scoop the $10-million trophy for commercial spaceflight, the rocket must repeat the flight, again carrying a pilot and the weight of two passengers above 100km, within two weeks. The second launch is scheduled for Monday 4 October.

SpaceShipOne, which is bankrolled by Microsoft co-founder and billionaire Paul Allen, first rocketed into the record books on 21 June, when it became the first privately funded, piloted craft to reach space. All other manned craft have been part of government space programmes.

On that trip, a hitch in the steering controls meant that the spacecraft barely scraped over the official 100-kilometre boundary between the Earth's atmosphere and space. Rutan's team says that it has since repaired the fault and tweaked the engine.

Reports from Wednesday?s flight said that the craft had rolled unexpectedly during its ascent, but flight controllers said that it had reached its target height.

Virgin territory

Supporters of the X prize hope that the competition will spur the development of a private space-tourism industry. That prospect edged closer to reality on 27 September, when entrepreneur Richard Branson announced that his Virgin group, which runs Virgin Atlantic airlines, had agreed to license the SpaceShipOne technology.

Branson revealed ambitions to build a fleet of spacecraft modelled on SpaceShipOne and, with tickets priced at more than US$200,000, to send up the first passengers as early as 2007. Spurring this type of commercial interest "is exactly what the X prize was intended to do" says Jim Benson, who heads the Californian company SpaceDev, which developed SpaceShipOne's rocket engine.

Other experts remain dubious that today's flight will open space to the paying public quite so fast. "It's not gonna happen next week," says John Logsdon, director of the Space Policy Institute at George Washington University in Washington DC.

For one thing, SpaceShipOne's trips into suborbital space allow passengers only a few minutes of weightlessness. In order to spend any longer there, a spacecraft must enter orbit some 300 kilometres or more above Earth. That requires an enormous leap in speed and power.

Some experts also question whether there are enough people willing to pay the steep prices necessary to keep a space company afloat. "There are a limited number of people who have a discretionary $200,000," Logsdon points out. Supporters of space tourism argue that the ticket price will drop with time.

Those who are tracking the X prize generally agree that SpaceShipOne is the only one of the 26 registered contenders with a serious shot at winning. But Benson says he is holding his breath for the second flight, because only then will the trophy be secure. "That's the one that'll win the prize and make history," he says.