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May 2014 magazine cover

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Outback Scramjet

A University of Queensland lab has supersonic success.

The promise of such data prompted researchers on the other side of the world to pay close attention to Paull’s HyShot program—so much so that NASA even became one of its sponsors. “We’re very hungry for flight data,” says Lawrence Huebner, manager of the Hyper-X scramjet propulsion program at NASA’s Langley Research Center in Virginia.

So what crucial decisions did Paull and company make to eventually achieve what Paull himself called their “beautiful” second launch? To start, Paull hired Hans Alesi, a German-Australian aerospace engineer who had read about HyShot and called to offer his services. Together the two men scrutinized potential engine designs, “trying to figure out how they could go wrong,” Paull recalls. “It’s like going out on a first date. There are a lot of ‘what ifs.’ ” They needed something that could withstand high temperatures, conduct heat well and did not bust their budget. They settled on an alloy of silver and copper, then commissioned university technicians to build it. The final result: a scramjet about half the size necessary to generate enough thrust to propel a craft, but large enough for their experiment.

Next they had to design and build the scramjet’s instrumentation module, which would control the flight and collect and transmit data. Several unexpected and time-consuming problems surfaced. Developing and testing a sophisticated attitude control device took a year and proved “a bigger challenge than the scramjet,” Alesi says in a lilting German accent. Paull and Alesi also had to design some of their payload test tools, such as a three-axis gimbal to simulate how the payload might rotate at the height of its trajectory.

The hitch-a-ride-on-a-sounding-rocket strategy was cheap, but was it cheap enough? As the HyShot timetable doubled and then tripled, Paull began to wonder if the team would run out of funds.

The University of Queensland, the Australian government, and QinetiQ (the privatized arm of Britain’s military research agency) had provided seed money for the project. Paull eventually secured additional funding from NASA,  the German and Japanese space agencies, Korea’s Seoul National University, and several Australian companies. Part of the appeal for the sponsors was Paull’s “clever and cheap way of getting this data,” says Terry Cain, a research fellow at QinetiQ, which is testing its own scramjet engine at one of the university shock tunnels.

Then, to stretch their modest budget, the team members got even more resourceful. Paull assigned students scramjet-related projects and in myriad other ways convinced people “to do things for free,” he laughs.

Some expenses were unavoidable: Wind tunnel tests (conducted an average of twice a day) cost about $500 per shot. To run them and also help out with other testing, Paull eventually hired one of his former graduate students, Myles Frost.

Lacking the resources to hire an expert for each task, he and his team members each wore many hats; Alesi sometimes found himself standing at a mill or a lathe, manufacturing some component for the payload. But they all say their big-picture perspectives encouraged them to come up with innovative solutions. Paull offers one such example: Forced to devise something that “weighed a kilo but could hold a ton” to keep the payload in place on the launch pad, Alesi designed a retractable lug that a private company has since expressed interest in buying.

Paull’s other big challenge was what he describes as an “amazing legal nightmare.” Like some B-grade horror movie plague, it ate up half his time, even after he hired another former graduate student, Susan Anderson, to help keep it at bay. The team had to secure authorizations from various state government agencies, coordinate with aviation bodies and insurance companies in both Australia and the United States (because of the involvement of U.S. funding), perform environmental assessments, and ensure their launch debris would steer clear of land claimed by Aboriginal tribes. They even had to visit area ranchers in person to allay their concerns. To complicate matters, the Australian government then grew jittery about anything taking place so close to a highly controversial refugee detention center. All told, the preparations took three and a half years. There were moments during that time when Paull wondered if transferring to a better funded program somewhere else might be the only way to fly a scramjet.

But surprisingly, at least to him, Paull had become something of a celebrity. In an isolated country accustomed to being a bit player on the world stage, his cutting-edge work was drawing considerable attention. Australian media coverage fired public enthusiasm to the point where new acquaintances congratulated Paull whenever he mentioned his work. HyShot was sometimes cast as a David versus Goliath affair, appealing to Australians’ affection for “battlers” persevering against all odds. “The strong effort we put in was appreciated,” Paull says. With that kind of moral support, “I couldn’t turn around and defect [to a program overseas] just to get the job done.”

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