The Sky's The Limit

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Standing at the woomera rocket-launch site in outback South Australia last month, Allan Paull and his team of scientists and engineers were about to stage a flight they hoped would herald a new age of air and space travel. They believed their jet engine could succeed, and had worked and scrounged for years to prove it. Now their meager budget was gone: after this final test flight, they'd be left with a stack of unpaid bills and a ute that had clocked 30,000 km ferrying them around the country. Waiting for the launch of the rocket that would carry their revolutionary HyShot engine 300 km into the sky, says Paull, "I thought that we couldn't do any better than we had-and if it wasn't good enough, well, it wasn't good enough."

As it turns out, it was definitely good enough. After two weeks of analyzing the flight data, Paull and his team last week announced they had pipped the global competition to achieve the first successful aerial test of a supersonic-combustion ramjet, or scramjet, engine. Scramjets burn their hydrogen fuel using oxygen from the air that is compressed-rammed-into the engine at supersonic speed. The jets have achieved ignition in ground tests, but never before in flight. "We believe we have done it," says an elated Paull.

Scramjet technology-which is predicted to slash the cost of space flight-is touted as the next great advance in air and space transport. "It would be a total change in the way we get access to space," says Glen Nagle of NASA's Deep Space Communication Complex at Tidbinbilla in the Australian Capital Territory. "Cheap access to space is the holy grail at the moment."

Scientists around the world have been trying since the 1950s to build a viable scramjet. The University of Queensland team-who knocked back offers to work abroad because they wanted their world-first to happen at home-beat rival projects on vast budgets with an 111-kg, 1.4-m-long scramjet that achieved combustion while traveling over Woomera at 2.4 km/sec., more than seven times the speed of sound. "We were the unproven, so there was this air of doubt that we could actually do it," says Paull. "And we were trying to do something everyone else wanted to do."

Scramjets' ability to grab oxygen as they move would eliminate up to half the weight of ordinary rocket engines, which must carry both fuel and the liquid oxygen to burn it. This means they have the potential to travel at high altitude and hypersonic speed, which is faster than Mach 5, five times the speed of sound; Paull says the goal is Mach 14. The aerospace community believes that could transform commercial air travel-predictions are already being made of two-hour Sydney-London flights. But the more immediate hope is for a revolution in space transport: the scramjet's lighter weight promises to slash the cost of putting small payloads, such as communication satellites, into orbit.

Given its potential, the global race for a breakthrough has been fierce. Paull's team of eight remained in Australia because, Paull says, "we wanted young Australians to be encouraged by our exploits. Something to aspire to other than sport-that's probably our biggest contribution to this country." But that meant surviving on a tiny budget provided by international and Australian supporters-while NASA's scramjet project has funding of around $180 million, Paull's team had to make do with $2 million. "It was a struggle," says team member Susan Anderson. "We weren't extravagant by any means." They were spared the huge expense of flight testing by an offer from U.S. company Astrotech of free piggybacks on two of its rocket launches at Woomera. They couldn't afford plane travel; instead they drove the two-day journey between the university in Brisbane and testing facilities in Adelaide, often camping along the way with the scramjet in the back of the ute. There was no money to pay an electrical technician to do the wiring, so Paull's father, who had wired cinemas in Queensland, came out of retirement. And Paull adapted a second-hand car-tire balance to fit the launch rocket's precious payload: "It was very much an Australian approach of, 'What do we have here that can get the job done?'"

But somehow, he says, "we always stayed one step ahead." The team had one of the world's best wind-tunnel testing facilities at the university and, Paull says, the lack of money kept them focused. "When you're driving together, camping together and in Woomera, living together, you start to create a bond," he says, "and when times were tough, that helped us get through." And got them back to Woomera nine months after their first test flight ended in rocket problems. But this time, on Jul. 30, in the final seconds of its 10-min. ride in the Orion rocket, the scramjet fired up and made history.

The next feat will be to perfect a free-flying scramjet that detaches from its rocket when the right speed is reached-something Paull says could be five years off. At least funding should no longer be a problem: a $50 million research program is being negotiated by Australian and international private and government investors. It might be a decade before a prototype is launched into space, and no one is even sure how fast scramjets will eventually fly. What does seem certain is that the HyShot engine's trip, from the back of a ute to those few seconds of combustion over the desert, is a forerunner of faster, higher journeys to come.