91av

AT A remote airport in California’s Mojave Desert last month, a tiny aerospace firm unveiled a spacecraft and launch vehicle it has been developing in secret for more than two years. The craft turned out to be among the most advanced of those competing to win the much vaunted $10 million X Prize for the first civilian crew to get into space. But if hype were rocket exhaust, the prize would have been won by now. While civilian space flight fans are supremely confident that someone will win the X Prize within months, the truth may not be quite as rosy.

Even a brief analysis shows that many of the two dozen contenders have little more than blueprints to show for their efforts, and even the teams who have built something will have a tough job getting their craft flight tested by the 2005 deadline, let alone into space.

And it doesn’t help that the prospects for making money from civilian space flight may have been sorely damaged by the loss of the space shuttle Columbia and its seven crew. The real reward for the winner of the X Prize will be a chance to dominate the potential $1 billion a year space tourism market. The competition is the brainchild of Peter Diamandis, an entrepreneur based in St Louis, Missouri, who recognises the role competitions have played in the development of many key technologies – including aircraft. The prize of $25,000 offered by American hotelier Raymond Orteig, for example, for the first non-stop flight between New York and Paris, inspired nine attempts and was eventually won by Charles Lindbergh in 1927. “Perhaps the X Prize can do the same for space,” Diamandis says.

The X Prize will be awarded to the first team to launch a three-person crew into space, flying up to an altitude of 100 kilometres and back down to Earth again. The feat must then be repeated within two weeks with the same craft. And the 24 groups who have entered only have until 1 January 2005 to do so.

At first sight, a sub-orbital flight might seem straightforward. After all, engineers have known how to do that for decades. In the 1960s, NASA carried out dozens of flights like this with an experimental aircraft called the X-15. Launched from beneath a B-52 at an altitude of 43,000 feet (13 kilometres) and travelling at 800 kilometres per hour, the X-15 was powered by a single rocket engine that burnt its entire payload of ammonia fuel and liquid oxygen in about 80 seconds. The X-15 could fly horizontally at Mach 6.7 – or go for altitude by flying up to a height of 100 kilometres, experiencing up to 5 minutes of weightlessness and then gliding down for a regular landing.

The plan unveiled in the desert by Scaled Composites of Mojave is uncannily similar. A high-altitude aircraft called the White Knight will carry a small rocket plane, dubbed SpaceShipOne, to 43,000 feet. This gets the rocket above the densest few kilometres of atmosphere so that it needs less fuel for its flight in space.

Designer Burt Rutan, who runs Scaled Composites, is trying a number of new technologies with these craft. SpaceShipOne’s rocket engine, for instance, relies on liquid nitrous oxide passing through a hollow cylinder of rubber. The liquid is a powerful oxidiser that combines with rubber to burn fiercely, generating thrust. The system is designed to combine the safety of a liquid rocket engine – it can be quickly switched off by closing a valve – with the simplicity of a solid rocket booster, which has few moving parts. Such hybrid engines can’t match NASA’s liquid oxygen and hydrogen motors for sheer thrust, but for sub-orbital flight, it doesn’t need to.

One problem with hybrid rockets is that nobody has used them in space before, says Frank Macklin, chief engineer at SpaceDev of Poway, California – one of two companies competing to build Rutan’s rocket engine. While simpler than many rockets, the engines pose problems. The way the nitrous oxide courses through the rubber can set up shock waves that make for unstable thrust. SpaceDev and its rival, Environmental Aerosciences of Miami, Florida, have both run 30-second burns on their rockets, but they need 65 seconds for a sub-orbital flight.

While the aerodynamics of SpaceShipOne have been extensively modelled on computer, Rutan has not carried out any wind tunnel tests. Instead, he hopes to validate the design by testing it in flight, slung beneath the White Knight. In the meantime, the would-be astronauts are expected to gain subsonic experience flying the White Knight, which has a similar flight control layout as the rocket plane.

Rutan is confident that none of the new technologies will fail. But if they become troublesome, it won’t be the first time an experimental vehicle has bitten the dust through overambition. NASA’s X-33 shuttle replacement came to a grinding halt in 2001 when it became clear that a new type of rocket engine and an exotic composite fuel tank design were just too difficult to complete, after spending $1 billion on the project (91av, 10 March 2001, p 4). Rutan, on the other hand, has under $25 million to do the job, from an anonymous backer.

Cash problems also spelled the end for the Roton launcher, a project that also required an entirely new rocket motor and an unusual landing system based on helicopter rotors (91av, 1 August 1998, p 24). The rocket was eventually mothballed in 2000 after a handful of test flights.

Rutan’s programme seems more advanced than most: White Knight has a few dozen flying hours under its belt and SpaceShipOne is largely complete but for its rocket engine. “I prefer not to speculate on which teams are the most promising,” says Diamandis. “Let’s just say that Scaled Composites has one of the most elegant entries.”

Few other teams have even built any hardware and those that do appear to be way behind Rutan’s team. Starchaser Industries in Britain, for example, is testing a liquid oxygen and kerosene rocket engine that would send a three-person crew on a sub-orbital hop and then parachute back to Earth. A liquid rocket motor, however, is a complex machine and it is not clear how well such a device could survive a parachute landing, as it must to be reusable.

And Advent Launch Services of Houston, Texas, a team of former NASA employees, has a liquid rocket spacecraft of its own that will glide back to Earth. But it has hit a major problem: the Texas Railroad Commission has refused permission to deliver the volatile liquid methane fuel it needs for its test firing in a Texas rice field. “We may have to liquefy our own fuel,” says Jim Akkerman, who leads the team. And there are other teams in Russia, Canada and Argentina at various levels of readiness – and secrecy.

What’s really driving these teams, though, is not the $10 million prize, which is likely to be a mere fraction of the cost of winning it, but a hefty chunk of the space tourism market in which adventurers will be expected to pay upwards of $80,000 for a 30-minute sub-orbital hop over the planet. While supporters of space tourism are adamant some people will be willing to pay, the deaths of Columbia’s seven astronauts – despite NASA’s billions – won’t help their business plans.

Nevertheless, this latter-day space race is hotting up. Just last week, it emerged that Jeff Bezos, the billionaire founder of Amazon.com, is bankrolling an X Prize attempt through a Seattle firm called Blue Origins. Its engineers are already said to be scouting launch sites in New Mexico. But Rutan has hinted that he could be ready to fly sooner rather than later. And that could make his remote corner of the Mojave Desert an exciting place to be this summer.