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Whatsapp An artist's illustration of NASA's X43a2 Scramjet

Australian scientists and engineers are at the forefront of a push to revolutionise the way we fly. The hypersonic scramjet engines they're developing have the potential to dramatically reduce international travel times. And as Antony Funnell reports, they could also have an impact on the way we launch satellites into space.

If all goes to plan, the western Queensland town of Roma will soon play a small, but important part in the future development of an Australian space industry.

Come December, a team of engineers from the University of Queensland's Centre for Hypersonics will descend on the region to begin flight tests as part of a three-stage space project dubbed SPARTAN.

Making something fly at those speeds is not actually that easy. As soon as you go outside the atmosphere there's a challenge because there's no air, there's no cooling.

The aim of SPARTAN is to construct a reusable satellite launching system using hypersonic technology; the testing at Roma will involve trials of a new type of rocket booster equipped with wings and a motor—adaptations that will allow the booster, called an Austral Launch Vehicle (ALV), to return gently to Earth after its fuel has been expended. The booster is being developed in conjunction with Australian company Heliaq Advanced Engineering.

Hypersonics is the science of very fast flight and the University of Queensland is a world leader in the development of what are called scramjets: special air-driven engines that contain no turbine and can reach speeds in excess of Mach 5—just over 6,000 kilometres an hour.

Crucially, scramjets only work when they've first reached hypersonic speed, hence the need for a first-stage rocket booster like the AVL. But once they're propelled to Mach 5 they then begin to power themselves.

The centre's director, Michael Smart, says SPARTAN is designed to capitalise on what he sees as a clear gap in the satellite launch market. Modern electronics, he says, have seen the size and weight of satellites decrease significantly. Many now weigh only around 100 kilograms. But there is no quick, cost effective way of putting them into orbit.

Professor Smart believes his reusable scramjet launcher could be the answer, significantly reducing satellite launch costs and improving launch date flexibility.

'At the moment there's a lot of activity in the small satellite area,' says Smart. 'Currently, there are about 1,265 satellites orbiting in space, but the cost to launch a single satellite is astronomical. Our project's aim is to reduce this cost and make it more economically viable for smaller nations and organisations to launch their own satellites and monitor their own space activity through the development of a reusable space launch system.

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Whatsapp HIFiRE launches an experimental hypersonic scramjet vehicle from the Pacific Missile Range Facility in Hawaii during a 2012 research flight.

According to Smart, anyone hoping to deploy a small-to medium-sized satellite is currently hamstrung by the launch schedules of the main rocket suppliers and by economics of scale.

'What they have to do at the moment is to tag along with a bigger launch. They either have to tag along with a Russian launch or perhaps a SpaceX launch, and that may sound okay, but the problem is that those larger launches are there to service their main customer. If you are just tagging along, you essentially just have to go along for the ride. You may be put into an orbit that is not optimal for what you are trying to do. You may not be able to launch when you want to, and it's a real restriction for this burgeoning area of technology.'

Smart describes the SPARTAN program as a once-in-a-generation opportunity for Australia's hypersonic industry to join the space community. But SPARTAN isn't the Centre for Hypersonics' only focus. In recent years Smart and his colleagues have also been collaborating on an international project called HiFIRE.

HiFIRE, which stands for Hypersonic International Flight Research Experimentation, is a research partnership with the United States Air Force, the US aeronautics company Boeing and the DSTG—the Australian military's Defence Science and Technology Group.

The partnership's most recent experimental field-test, HiFIRE 7, was conducted earlier this year at a rocket launching facility in Norway. During that trial a scramjet engine designed and constructed at the University of Queensland reached a speed of Mach 8—nearly 10,000 kilometres an hour.

The eventual aim of the project is to develop aircraft so fast that they can travel huge distances in very short time frames—between London and Sydney in around two hours, say. By contrast, the super-sonic Concorde took 17 hours to cover the same distance, flying at Mach 2.

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Whatsapp The NASA X-43A hypersonic research vehicle and its Pegasus booster rocket mounted beneath the wing of a B-52 bomber in April, 2001.

The commercial and military potential of such a development are immense, but despite the success of testing so far, no one involved in HiFIRE downplays the difficulty of perfecting hypersonic flight.

'Basically it's hard,' says Allan Paull, the DSTG's research leader for Applied Hypersonics.

'To do anything in hypersonics you've got to have either good wind tunnels or very good computational facilities. Or, if you are really serious, you've got to do flight testing. And all of the above actually costs a lot of money and requires a lot of technologies.'

The DSTG provided the flight vehicle for the recent experimental test in Norway and Dr Paull says the main aim of that test was to more accurately define the thrust of a scramjet engine travelling at such enormous speed and to monitor how the flight vehicle supporting the scramjet coped with the transitions in and out of the Earth's atmosphere as it skimmed the edge of space.

'The main technical challenge that we face is to do with heating,' he says. 'Making something fly at those speeds is not actually that easy. As soon as you go outside the atmosphere there's a challenge because there's no air, there's no cooling.

'There is also a chance that, because of the lack of air, things can actually explode. But we avoid most of that by pre-testing in a vacuum. Then when you re-enter the atmosphere, it's not just like atmosphere on/atmosphere off, there's this slow changeover between what we could call nothing and air. That slow changeover—a lot of aerodynamics is unknown in that area.'

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Whatsapp X-43A hypersonic research aircraft testing at Dryden Flight Research Center, California

HiFIRE isn't the only research initiative centred on hypersonic flight. There are various organisations and institutions in the US, Europe and Asia working on super-fast travel, including the Chinese military.

But one of the things that gives the HiFIRE project an advantage is the diverse nature of the consortium, which involves government, academia and the private sector, says Kevin Bowcutt, Boeing's chief hypersonics scientist.

'Everybody has a different role. The government tends to be a user of things, a user of technology, a user of systems; they provide a lot of the funding for research and development. Academia will dig into the nitty-gritty science and the details of problems and try to do things that maybe industry won't do because industry's job is to build things and build products and make money.

'So everyone has got a different part, and if you bring all those parts together you can attack the problem and maybe get to a better solution.'

The next HiFIRE test flight is scheduled to take place at Woomera in South Australia in 2016.

Exploring new ideas, new approaches, new technologies—the edge of change. Future Tense analyses the social, cultural and economic fault lines arising from rapid transformation.



