Start your engines ... is China getting ready to mass-produce hypersonic vehicles?
Plans are on the drawing board in China for an engine plant that could power low-cost planes or spacecraft capable of travelling five times faster than the speed of sound
China is drawing up plans for an aerospace engine plant that would pave the way for the mass production of “hypersonic” planes or spacecraft capable of travelling at more than five times the speed of sound, boosting the country’s competitiveness in defence, space, business and other sectors, according to scientists familiar with the project.
The plant that would be built in Hefei, in China’s eastern Anhui province, could give the country an edge over the United States and Russia in the race to achieve large-scale applications of hypersonic technology, the scientists said.
Hefei deputy mayor Wang Wensong led a delegation to the Institute of Mechanics at the Chinese Academy of Sciences in Beijing last month to discuss the project’s roll-out, according to a statement on the institute’s website.
The Institute of Mechanics, or Imech, is a major developer of hypersonic weapons in China. It studies the behaviour of extremely fast, hot gases – also known as aerothermodynamics – in engine design, using some of the world’s most powerful and sophisticated wind tunnels in its work.
The institute would “join hands” with the Hefei government to build the engine plant, which would be able to operate on a commercial scale when completed, according to the statement on the institute’s website. No completion date for the project was given.
The project would add to Hefei’s growing reputation as China’s “science city”. In the past decade it has become the backdrop for the nation’s first quantum computer and fusion reactor.
The engine project was the result of Beijing’s campaign to use breakthroughs in military technology to stimulate economic growth, according to the institute’s statement.
Fan Xuejun, head of Imech’s “scramjet” division – focused on using high vehicle speed to compress incoming air forcefully before combustion – was lead scientist for the project.
Fan told the Post that the plant would make engines in a range of models for customers in military and civilian sectors.
Scramjet, short for “supersonic combustion ramjet”, is a high-speed propulsion technology that could cut flying time from Shanghai to New York to just two hours – a fraction of the almost 15 hours a commercial passenger plane takes to cover that distance.
Fan declined to discuss the design of the engine that would be made in Hefei. But he said one of its uses could be as the power source for space missions.
“The purpose is to cut the cost of space launches,” he said. “It is similar to [the goal of] SpaceX, but we are taking a completely different approach.”
SpaceX, a private US space company founded by entrepreneur Elon Musk, has developed recovery technology that can return rockets to Earth for reuse. It seeks to cut the per-kilogram cost of space launches to just thousands of US dollars from tens of thousands of US dollars.
A government-funded company is to be established soon to build and operate the Hefei plant, according to Fan. In the future it could sell shares to private investors.
Project details would not to be released to the public until the business entity was officially established, he said.
HOW THE ENGINE WORKS
Some analysts said they believed the Hefei-produced engine could be a variant of a rocket-based combined cycle system under intensive testing at Imech’s ground facility in Huairou, Beijing.
The system could use a conventional turbine engine for take-off and acceleration to supersonic speed – faster than the speed of sound – then fire up the scramjet to reach hypervelocity. A rocket would give the vehicle a final push to bring it up to orbital height.
Researchers familiar with the project agreed that the engine, which puts three different types of propulsion technology in one package, could indeed significantly reduce the cost of space flight.
Conventional space launches are carried out using rockets. A rocket engine not only must carry fuel such as kerosene or hydrogen but also a large tank of oxygen, possibly increasing the overall weight of fuel at launch by nearly a third.
Most rockets either crash in the ocean or burn up in the atmosphere after use, adding to the cost of space flight.
The scramjet technology could allow a projectile to achieve rocket-like speed without the burden of an oxygen tank.
A scramjet-driven spacecraft could breathe in the thin oxygen of the upper atmosphere. It could also return to Earth and touch down on an airstrip like a normal plane.
But harnessing scramjet technology for a practical space application has proven to be extremely complex and difficult to achieve. Scientists have compared the effort to control the combustion in a scramjet engine to keeping a candle lit in the teeth of a hurricane.
With air moving into the engine at an extremely fast rate, a tiny jolt in fuel supply, for instance, could extinguish the combustion in the engine and lead to the vehicle’s crash.
Scientists in the hypersonic research community believe that Russia, the US and China have recently overcome the technical hurdles and achieved the long term, stable operation of scramjet engines.
In contrast, India, which tested a pair of scramjet engines mounted on a two-stage rocket in 2016, managed to keep the burning going for just five seconds.
China and the US could be neck and neck in the race to achieve a mass application of hypersonic technology, but both countries remain a step or two behind Russia, according to Liu Hong, an award-winning hypersonic scientist at the school of aeronautics and astronautics at Shanghai Jiaotong University.
In March, Russian President Vladimir Putin said his country’s military had deployed the world’s first hypersonic weapon system. The intercontinental hypersonic missile, Putin said, would fly to targets at 20 times the speed of sound.
“Putin is telling the truth,” Liu said. Though the hypersonic weapon tests in the US and China received the most media coverage, it was generally agreed among researchers that “the Russians are the leader in this field”, he said.
ITS PRACTICAL APPLICATIONS
The rocket-based combined cycle system could be the first hypersonic power source to be applied in real life because it had been developed and tested for many years, according to Liu.
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“If [the Hefei plant] is taking the approach, which is relatively simple and mature, I think their goal for commercial production is possible. It is within the reach of current technology,” he said.
The Institute of Mechanics is not alone in its endeavour to understand and develop hypersonic vehicle technology.
In China, at least four or five major state-owned companies or government organisations also have unveiled ambitious plans to make use of hypersonic flight science, according to Liu.
In 2016, China Aerospace Science and Technology Corp said it was developing a hybrid space plane that would take off and land in a normal airport with a combined cycle engine.
Its major rival, China Aerospace Science and Industry Corp, launched a similar project called Teng Long, or soaring dragon, soon afterward.
In early March, the China Aerodynamics Research and Development Centre, the hypersonic weapon development branch of the People’s Liberation Army in Mianyang, Sichuan province, announced a successful test of a prototype spacecraft in the Gobi Desert, in Inner Mongolia. The vehicle was believed to be a hypersonic space plane.
Each player in the hypersonic vehicle race “has a unique technological advantage”, Liu said.
“In the end I believe the government will scoop the cream of the technology of each project and put them together to build a high-performance vehicle,” he said.
The market demand for the hypersonic space vehicle could be big enough to create a multibillion-yuan business.
“If it can save 10 tonnes of fuel for each launch, which is already a very conservative amount, orders will fly in,” Liu said.
The impetus for China’s hypersonic programmes initially came from its defence sector. The military’s leaders salivated at the idea of a high-speed vehicle that could penetrate any existing missile defence system, strengthening China’s nuclear deterrence capability.
Rapid advancement in hypersonic technology in recent years also has sparked interest in its potential application in non-military sectors, Liu said.
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For instance, space planes could bring satellites into orbit or establish a global communication network – all at low cost.
Doing so could bring cheap or even free Wi-fi to everyone, anywhere. Such an accomplishment would benefit Chinese businesses such as internet and mobile phone companies, as well as the increasing number of Chinese citizens travelling overseas, according to Liu.
Beijing’s launch of its massive infrastructure plan – the “Belt and Road Initiative” – would be impossible without the support of space-based facilities, he said.
Liang Xiaohong, former party secretary of the China Academy of Launch Vehicle Technology, has said that the value of potential orders for satellites and space-related services from Beijing and China’s business sectors is estimated at 1 trillion yuan (US$159.32 billion).
The figures reflected China’s desperate need for reliable, low-cost launch vehicles, Liang said.
Although production lines for China’s existing Long March rockets supported about 35 launches per year – on par with the US – the output could not meet the country’s huge demand for satellites, he said.