The Spaceplane Revolution Isn’t Lightyears Away

What are spaceplanes?

A spaceplane is precisely what it is called: a plane that glides through space. More specifically, it is an aerospace vehicle that can operate as an aircraft in the Earth’s atmosphere and a spacecraft in orbit. Spaceplanes typically combine core features of the two and have been tried and tested due to their advantages compared with rockets, such as manoeuvrability in space, their reusability, their access to space through established infrastructure – such as airports – and their efficiency. 

Spaceplanes that have been launched into space in the past have gone two ways: through rocket power or vertical take-off horizontal landing (VTHL). According to NASA, rocket-powered spaceplanes typically are carried up to an altitude of tens of thousands of feet by an “atmospheric mother ship” before being released and then flying above the Earth’s atmosphere. VTHL launch is like a standard rocket being propelled into space but landing like a typical aircraft.

Aside from countless prototypes and some currently being designed, five spaceplanes have successfully flown into space and returned to Earth safely to date. This includes the North American X-15, which first flew in 1959 and was an experimental hypersonic rocket-powered aircraft operated by the US Air Force and NASA, and NASA’s famous Space Shuttle, which was instrumental in building the International Space Station. Then there was Russia’s Buran spacecraft, the first operational Soviet shuttle orbiter, an experimental sub-orbital spaceplane built by Burt Rutan, and lastly, Boeing’s X-37, a reusable spacecraft that lands as a spaceplane and is operated by the US Space Force. 

While some of these, especially the Space Shuttle, were highly successful during their time, spaceplanes remaina concept that hasn’t fully taken off in the commercial sector. 

An Aussie company betting on making spaceplanes a reality

Michael Smart, co-founder and head of R&D of Australian company Hypersonix Launch Systems, says that the technology is simply the “next thing in access to space”.

“The Montgolfier brothers developed the air balloon, then the Wright Brothers developed fixed-wing flight, and then propeller technology moved on. Then in the Second World War, jet propulsion came on board,” Smart says. “All these new technologies came along to make aircraft technology more efficient, faster, safer … So, spaceplanes, particularly these scramjet engines, are the next technological leap in access to space.” A scramjet is an engine in which airflow through it remains supersonic or greater than the speed of sound.

Late last year, the company signed a deal with the University of Sydney to bring a zero-emission spaceplane concept to life, capable of deploying small satellites into low-Earth orbit. The 12-metre vehicle – dubbed Delta Velos Orbiter – would be powered by four green hydrogen-fuelled scramjets (supersonic-combustion ramjet) engines, enabling carbon-neutral propulsion. It would also include the first 3D-printed fixed geometry scramjet in Australia, completed under a grant awarded to the company in 2020. 

The vehicle will be able to accelerate from Mach 5 – five times the speed of sound, and the base speed of being hypersonic – to Mach 12, unlike any other spaceplane in the world. It will be able to manoeuvre to different orbital planes, deploying satellites into their desired orbits, which is something a rocket cannot do. The spaceplane has been developed to cater to small satellites up to 150 kilograms or larger ones up to 300 kilograms. It would launch vertically on a rocket up until Mach 5, and then it would then complete a gravity turn. Delta Velos will then launch off the rocket horizontally and accelerate up to Mach 12 as it rips through the Earth’s atmosphere with the help of a small third stage. 

Smart says that one of the biggest challenges in flying to space is the atmosphere – or, as he likes to call it, “the enemy” – because it creates severe drag, and you need materials that can survive those high temperatures. “But a spaceplane uses the air to generate lift,” Smart says. “When you use a scramjet engine, we use oxygen from the air to burn without fuel to create thrust, and so we don’t have to carry our oxygen like rocket systems have to carry an oxidiser.” For instance, the Space Shuttle’s engines used a toxic substance called hypergolic propellant. 

“Spaceplanes… are the next technological leap in access to space”

So, is Hypersonix set on rivalling SpaceX then?

Like an airline that doesn’t throw out its aircraft after every use, Hypersonix plans to be the same with its spacecraft, taking reusability the next step further. “Right now, 90 per cent of almost everyone except SpaceX throw away every bit of their rocket system every time, and it’s just so wasteful… and it’s seriously expensive,” Smart says. 

Elon Musk’s SpaceX, founded in 2002, has been the world leader in reusable rocket stages and showed that access to space could become more sustainable and cheaper. While it would be interesting to see an Australian company strive to compete against Musk’s company, that isn’t exactly the case here. Michael Smart says SpaceX’s systems are pretty big, operating to launch around 10,000kg into orbit at a time. Their spacecraft are being built to take things to Mars eventually and beyond. But Hypersonix is set to grow the smaller market by launching satellites less than 300kg into low-Earth orbit.

“Our focus is to use this new technology to prove it in the small satellite market first because it has broader possibilities for hypersonic aircraft,” Smart says. “This small set marketplace is actually quite a nice business to prove our technology. A lot of the other players really struggle with launch costs because if you throw your rocket away every time, it’s really hard to create cheap launch … It might be the reason why initially we’ll be able to compete very strongly with other small satellite launchers.”

The small satellite market continues to grow. Weather predicting, natural disaster monitoring, water management, GPS systems, and internet connectivity all rely on satellites. Currently, just over 12,000 satellites are orbiting the Earth, and that number is set to skyrocket to hundreds of thousands in the next decade. As Australia’s first astronaut Paul Scully-Power says, it’s the next technology revolution. 

Another reason it is not a goal to compete against SpaceX is that while Musk’s company launches satellites and other objects into space, some will fail or be dead on arrival, and they cannot be fixed or deorbited immediately. But Hypersonix’s spaceplane would be able to “precisely” replace each satellite and even reposition them. “So, our business model is not to compete with SpaceX on rideshare; we’re there to help SpaceX maintain their Starlink system or other companies that have all their other constellations by replacing things quickly, precisely and responsibly,” Smart adds.

Reusable rockets have put a hold on the spaceplane market

Before reusable rockets came on the market, spaceplanes were more highly considered a better option. But according to Martin Rowse, the head of space at Airbus Australia, reusable rockets have left a drier market demand for spaceplanes to rise. “When Airbus was looking at it seriously, in around 2004, 2006, I think that’s when we didn’t have reusability of rockets,” Rowse says. “We were looking at how we reduce the cost of access to space because the cost of access to space is such a driver for the space industry that it becomes a determining factor.” In 2007, Airbus unveiled a mock-up spaceplane concept in Paris called the EADS Astrium TBM. It was set to be a suborbital spaceplane to carry space tourists. It was expected to begin development in 2008, but as of 2015, the venture was still waiting for investors. 

“I think what we’re seeing with that reusability is because you can do so many different things with them, the need for space planes doesn’t currently stack up”, Rowse says. He adds that in the coming years, the industry will continue to send tourists into space – like the recent Axiom mission to the International Space Station and SpaceX’s Inspiration 4 mission in September last year – and the success of spaceplanes comes down to the need for them. In Rowse’s opinion, “none of those aspects are coming into line”. Nevertheless, Rowse says that “it’s not to say it won’t in the coming years”.

The emergence of reusable rockets may have also blocked a viable supply chain available for spaceplanes to dip into. Rowse says to make spaceplanes “economically viable”, it is paramount to have a supply chain. He says that Australia’s space players are looking outward for investments, which will be essential to finding suppliers and customers worldwide. At the moment, however, he believes there is a lack of supply chain for spaceplanes, ultimately fuelled by the demand for reusable rockets. 

But Smart poses a compelling argument: There isn’t really a supply chain in the first place, and there doesn’t need to be. While that sounds controversial, he says the nature of the technology is reusable, meaning unlike when rockets are thrown out after use, requiring a complete restock of components, spaceplanes don’t need that. Smart says Hypersonix’s spacecraft will be more like a Qantas aircraft, which will be refurbished and undergo maintenance when required but, once approved, can return to the sky quickly. “So, the supply chain is more like an aircraft system than a space system… it’s quite different.” Arguably though, spaceplanes also need a renewable power supply in orbit to keep them running and the ability to manoeuvre around space like an aircraft, which presents a new set of challenges to combat.

Without question, spaceplanes are more sustainable

Despite SpaceX’s groundbreaking technology that paved the way for reusable launch in space, spaceplanes take sustainability to another level. Sustainability is a popular buzzword in all sectors, and in recent years has also infiltrated space jargon. It is now clear that consumers care about sustainable practices in space, whether developing technology that uses less toxic fuel, creating spacecraft that can deorbit to eliminate generating space junk, or even becoming a business focused on cleaning out space debris. Whatever it is, there is a rising movement toward a sustainable space industry.

Smart says that there are three core ways Hypersonix’s spaceplane, in particular, is sustainable: ceramic matrix composites, scramjets and hydrogen. According to Smart, it took around 30 years to develop scramjet technology that can power an engine up to Mach 12, or 12 times the speed of sound, which “no one else” has achieved. Making a sustainable spaceplane that can withstand astronomically high temperatures is hard, so hard that the spaceplane would melt without certain materials available. Ceramic matrix composites, a specific composite group made of ceramic fibres, can operate between 1,500-2,000 degrees. Without CMC, Hypersonix couldn’t create its 3D-printed scramjet engines. Hypersonix won a grant in February to develop these materials, as they are not available in Australia yet.  

As Smart also called “luck”, what came easy for the company was that the hydrogen market had already been established long before. “We don’t want to have to develop hydrogen tanks, for example, that would be safe to use,” he says. “These tanks have all been around over the last 10 years; they’ve been developed in the automotive industry for buses and trucks. So, we can tap directly into all the infrastructure.” Hypersonix’s scramjet engines will be fuelled entirely by hydrogen, which has also become a significant part of aviation’s sustainable growth, as well as sustainable aviation fuels (SAF) made out of food waste and left-over cooking oils. 

“So, there are three things that have happened all at once,” Smart says. “And as we’d like to say, it’s really good to be lucky and smart… but luck really helps.” 

Aside from Hypersonix’s spaceplane being made sustainable, it doesn’t mean all other brands will be. The very nature of spaceplanes being reusable is a good sign, however. 

Who will make it happen?

Before the commercial industry emerged, space was a tight-lipped sector only dominated by government entities and huge companies with high capital. With the demise of the space shuttle in 2011 over excessive costs and unsafe operations and Boeing’s X-37 being primarily used by the US Space Force, there is room for smaller companies to lead the charge in providing access to space for all types of customers. 

Hypersonix Launch Systems is not the only company spearheading this technology. Close to Australia, Dawn Aerospace, headquartered in Christchurch, New Zealand, offers a similar product. The spaceplane, named Dawn Mk-II Aurora, is designed for multiple flights per day, flying to 100 kilometres and above. The difference with Dawn, compared with Hypersonix, is that this spaceplane operates entirely like a standard aircraft but in space. It is a sub-orbital vehicle that can take off and land from any conventional runway, allowing the spaceplane to utilise all available airports. The company is licensed to operate as an aircraft, not needing launch zones, airways or waterways. The spaceplane’s 3U payload can host science experiments, paving the way for Dawn’s next vehicle that will be capable of delivering 250kg in orbit. 

“There is a different way than launching rockets, throwing them in the ocean and building another one”

Dawn can fly at a maximum speed of Mach 3+ and commenced five test flights late last year, assessing its airframe and avionics. About a year earlier, in December 2020, the New Zealand Civil Aviation Authority (CAA) granted Dawn a certificate to fly its spaceplane from a conventional airport with no airspace restrictions, a significant vote of confidence for easy access to space. But unlike Hypersonix, Dawn Aerospace uses a mix of high-test peroxide and kerosene in its engine. 

While generating much controversy, Virgin Galactic has also developed a spaceplane; however, it is made solely for space tourism. The suborbital spaceplane, which completed its first few manned flights last year, was first unveiled in 2009 and achieved initial unmanned tests in 2013. Unlike the Dawn, Virgin Galactic’s spaceplanes are carried by a mothership – like the Space Shuttle – until reaching its launch altitude (at 50,000 feet) and then released to fly into the upper atmosphere by its rocket engine. According to Sir Richard Branson’s company, the for-sale flights last 90-minutes. While the vehicle is similar to other spaceplane companies, Virgin’s is merely for space tourism and not for satellite or payload deployment. 

But the space tourism market is where spaceplanes could thrive, Rowse says, despite ongoing criticism. “I think the interesting thing with spaceplanes, and what you can see in the near future, is spaceplanes [being used] for more human flights,” he says. “In having that reusability and almost more comfortable flights from a horizontal runway base, I think would be much more beneficial than we currently do it through big launch vehicles.” 

While other prototypes and concepts are floating around the world, it just might be that the real success of a sustainable and reusable spaceplane will be homegrown. Smart says that while spaceplanes have been a futuristic concept, more than a commercial reality, “people are more open-minded to something new” now due to the increasing awareness of sustainability in space and on Earth. “It’s just about discussion, going to venues, talking to people and just trying to open their minds to that there is a different way than launching rockets, throwing them in the ocean and building another one when you want to launch next,” he adds.