Australia’s contribution to hypersonic flight

Slow and steady wins the race – especially in hypersonic flight. Now Australia’s persistence in pursuing high-speed technology is paying off.

Brisbane-based Hypersonix Launch Systems has received a $2.95 million grant from the Australian Government to develop the world’s first fully reusable aircraft capable of flying at up to 12 times the speed of sound.

The ultimate goal is a multi-mission autonomous vehicle that can launch satellites into orbit while emitting only water vapor as exhaust.

It has taken decades of effort to get to this point.

Australia’s Defence, Science and Technology Group (DST) and the university sector have been involved with the technology since 1989 when they conducted their first scramjet ground tests. The HyShot flight test program took to the skies in 2022. And the hydrogen-powered scramjet HIFiRE 7 flew in 2015.

The new DART CMP drone will be a complete technology demonstrator package being developed in collaboration with the University of Southern Queensland. At its heart will be a 3D-printed hydrogen-powered scramjet engine from Spartan. However, this must be fitted to an Australian made airframe with associated control surfaces and flight avionics.

Hypersonic propulsion is a competitive field. More than 100 companies are exploring the technology internationally, but Hypersonix is ​​hoping its hydrogen-powered 3D scramjet combo will be a winner.

Now it has attracted the attention of the United States after a number of its own high-speed controlled flight projects failed. Australia’s hypersonic edge is its main contribution to the AUKUS framework for defense cooperation sharing.

Sleek, green machine

Unlike rockets, scramjets draw combustible oxygen from the atmosphere. This reduces the weight to be carried by around 60%. And the Spartan engine burns hydrogen fuel in a process that releases water vapor, not carbon dioxide, as exhaust. If this hydrogen comes from renewable energy sources, the reusable 3D-printed scramjet engine becomes particularly “green”.

But hypersonic flight is difficult to achieve. And even harder to keep.

The scramjet engine itself reaches internal combustion temperatures in excess of 1000°C. And the airframe is another challenge, as it must support both significant loads and heat.

Hypersonix co-founder Dr. Michael Smart says the advantage of the Spartan engine design is that it has no moving parts that are potential sources of failure. “Rather than having all the rotating blades and compressors, we just use the shock waves and the air itself to create combustion,” he says.

This makes the engine more resilient, reliable and reusable.

Hypersonix CEO David Waterhouse adds that the engine can be cycled on and off, allowing the vehicle to “deflate” like a pebble over water. This allows the vehicle to cover significant distances with minimal fuel consumption.

Hypersonix has simulated how its scramjet engine and DART airframe will perform at speeds in excess of Mach 5. This was also proven by a series of hypersonic impact tunnel tests. Now it needs the appropriate manufacturing technology necessary to bring the engine and its airframe to reality.

And this is where the new subsidy from the federal government comes in. It is intended to give Australia the sovereign ability to produce the advanced materials it needs. These include advanced high-temperature oxide-oxide ceramic matrix composites that promise to be more cost-effective than titanium and other high-temperature alloys.

demonstrator

Hypersonix is ​​currently in the process of assembling its DART AE 3D printed demonstrator vehicle. The subsequent DART CMP will focus on the integration of composite materials.

“AE stands for Additive Engineering (or 3D Printing) and is the fully 3D printed version using high temperature alloys that are already available in Australia,” says Waterhouse.

The use of 3D printing means the Spartan engine is both cheaper to build and more resilient due to its seamless assembly. It is able to withstand about 1500 °C. And Hypersonix says it only takes three weeks to print a new one.

The autonomous technology demonstrator is to fly more than 500 kilometers between Mach 5 and 12. It must also be able to control its speed, flight profile and return to a landing location.

DART AE is scheduled to hit the market in 2023. The new DART CMP project starts in July.

Executive Director of the University of Southern Queensland’s Institute for Advanced Engineering and Space Sciences, Professor Peter Schubel, says his team will develop and test the ultra-high temperature composite materials and coatings the new vehicles will need.

“Our expertise in liquid forming technologies, automated fiber placement, pultrusion and filament winding capabilities with exotic materials allows us to develop revolutionary structures,” he says.

But not everything about the DART is likely bespoke. Smart says its hydrogen fuel tank could be an off-the-shelf tank used for hydrogen-powered trucks and heavy vehicles, as they are already very resilient.

Much depends on the success of the demonstrators.

A conceptual image of the proposed Hypersonix Hypersonic Autonomous Vehicle Hypersonix DART CMP. Photo credit: Hypersonix Launch Systems

On April 6th, Australian Prime Minister Scott Morrison, US President Joe Biden and British Prime Minister Boris Johnson finalized their cooperation plans for AUKUS defense technology. The development of hypersonic flight technology was at the top of that list.

It is widely believed that after years of failed US projects, Russia and China have a technological lead in this area. Moscow claims to have used such weapons against targets in Ukraine.

“There is an arms race, not necessarily for more numbers, but for more quality,” US Air Force Secretary Frank Kendall said late last year. “It’s an arms race that’s been going on for quite some time. The Chinese have been very aggressive.”



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