Although China is downplaying its hypersonic testing, recent demonstrations are showing an increase in missile maturity.
On 27 October the chairman of the US Joint Chiefs of Staff (JCS), General Mark Milley, confirmed that China had tested a new hypersonic weapon system, noting that the test launch was a “very significant” and “very concerning” development for the US military although he did not elaborate.
“I think I saw in some of the newspapers that they used the term ‘Sputnik moment’,” General Milley said. “I don’t know if it’s quite a ‘Sputnik moment’, but I think it’s very close to that. It has all of our attention.”
The general’s remarks are the Pentagon’s first official acknowledgement of China’s hypersonic test first reported by the Financial Times on 16 October, which claimed that the People’s Liberation Army (PLA) had launched a rocket carrying a hypersonic glide vehicle (HGV) that circled the globe in Low-Earth Orbit (LEO) before descending towards its target, although the HGV had reportedly missed “by about two dozen miles”.
However, Beijing denied that the test was military in nature, with foreign affairs spokesperson Zhao Lijian asserting that it had been a “routine test of spacecraft to verify technology of [it’s] reusability”.
“It is of great significance to reducing [sic] the cost of using spacecraft and providing a convenient and cheap way for mankind’s two-way transportation in the peaceful use of space,” Zhao told reporters during a 18 October briefing. “Several companies around the world have conducted similar tests.”
“After separating from the spacecraft before its return, the supporting devices will burn up when falling in the atmosphere and the debris will fall into the high seas,” he added, without providing further details.
Very little detail about China’s alleged hypersonic weapon test has emerged, but it is believed that the HGV was launched on a polar LEO by a Chang Zheng 2C CZ-2C orbital launch vehicle, which is produced by the China Aerospace Science and Technology Corporation’s (CASC’s) China Academy of Launch Vehicle Technology subsidiary. The CZ-2C is also understood to be a derivative of the PLA Rocket Force’s (PLAARF’s) Dong Feng-5 (DF-5) intercontinental ballistic missile. According to reports, the launch vehicle can deliver payloads of up to 3,086 pounds (1,400 kilogrammes) when configured in its two-stage version.
The same concern was echoed by JCS vide-chairman General John Hyten in a November interview with CBS News, noting that the rocket “went around the world, dropped off a hypersonic glide vehicle that glided all the way back to China, that impacted a target in China.”
Hypersonic missile gap
General Hyten noted that while the US military is also developing hypersonic weapons, China appears to have taken the lead with “hundreds of hypersonic tests” carried out in the past five years while the US conducted just nine. The general also pointed out that the PLA has already deployed one medium-range hypersonic weapon, while the US is still “a few years from fielding its first one”.
The US military’s concern over China’s hypersonic weapons technology development is clearly understandable, given that such weapons that can travel at extremely high speeds in excess of Mach 5 (over 6,000km/h). Broadly speaking, there are two main types being pursued today: hypersonic cruise missiles and HGVs (or waveriders).
The former is equipped with an on-board air-breathing engine such as a scramjet or ramjet to travel under its own power to its target, while the latter uses a re-entry vehicle that uses a booster such as a rocket to accelerate into space at before ‘gliding’ down to its target using the shockwaves of its own extreme-speed descent.
“The main concern over hypersonic weapons is that there is no operational missile defence system today that is capable of intercepting these weapons, which is why the present race to develop hypersonic weapons – with countries such as Australia, China, Japan, India, Russia, and the US involved either as national or collaborative development – is such an important one,” Feng Zhu, a senior researcher at a state-sponsored research institute, told AMR.
“Of these, China, Russia, and the US appear to be the furthest along with their development and have performed significant testing in recent years,” explained Zhu, noting that Russia’s air-launched, nuclear-capable Kh-47M2 Kinzhal missile has a claimed range and maximum speed of more than 2,000km and Mach 10.
“[As such], the recent Chinese test of a hypersonic vehicle is concerning for the US military regardless of whether it is a missile or spacecraft because the feat demonstrates that China is likely further ahead in operationalising this capability,” he added. “China is clearly committed to accelerating hypersonic technology development, although most of its development efforts remain highly classified.”
Indeed, Zhu noted that the country has poured significant investments into maturing hypersonic flight and testing capabilities for at least the past decade, with its primary science and technology agencies aligned with Beijing’s desire to develop advanced weapons for its military.
One such example is the experimental DF-ZF HGV, which had reportedly been tested on at least eight occasions since it was first documented in 2014. Earlier reports have suggested that a DF-ZF prototype – which was earlier identified by the US Department of Defense (DoD) as the WU-14 and is believed to comprise a DF-17 medium-range ballistic missile (MRBM) with a HGV payload – successfully completed a November 2017 demonstration from the Jiuquan Satellite Launch Centre (JSLC) in Inner Mongolia. The HGV reportedly travelled approximately 1,400 km following its atmospheric re-entry phase, achieving speeds of over Mach 9 (11,265km/h) during its flight.
The DF-17 MRBM system was first revealed to the public on 1 October 2019 during the 70th anniversary military parade to mark the country’s founding. The maximum estimated range for the DF-17 varies in open sources from 1,800km to 2,500km. US intelligence sources reportedly noted that at least several DF-17 test flights were conducted by the PLAARF in November 2017.
Defence industrial capabilities
The state-owned space and defence technology prime China Aerospace Science and Technology Corporation (CASC) appears to be front-runner in China’s hypersonic weapons development race, with its flight technology development arm China Academy of Aerospace Aerodynamics (CAAA) announcing in August 2018 it had successfully developed and tested an experimental HGV called Xing Kong-2 (Starry Sky-2). It is understood that the test vehicle was launched by a solid-propellant rocket supplied by the Fourth Academy of the China Aerospace Science & Industry Corporation (CASIC), also known as the CASIC Delivery Technology Technical Research Institute.
According to CAAA, the internally funded demonstration was aimed at validating core technologies that are vital to hypersonic flight, with the research institute noting that the test vehicle was subsequently recovered in its complete state at a designated landing zone.
“The test has laid a solid technological foundation for engineering applications of the waverider-type design,” the institute said in its statement, adding that the effort has enabled its technical staff to acquire valuable performance and telemetry data for further refinement of indigenous hypersonic aerodynamics such as micro-vortex generation, as well as other critical elements including flight control and guidance, payload separation, propulsion, and thermal protection technologies.
According to CASC, the test vehicle has been in internally funded development since around 2015 and was launched from a facility in north-western China (likely JSLC). It separated from the booster rocket following a 10-minute ascent and controlled transition, engaging its own propulsion system to perform independent flight for over 400 seconds and attaining a maximum claimed speed of Mach 6 and flight ceiling of 30km (18.6 miles). The demonstration, which was aimed at validating core technologies that enable hypersonic flight, was deemed “completely successful” with CAAA claiming that the test vehicle was subsequently recovered in its complete state at a pre-designated landing zone.
CAAA operates several hypersonic wind tunnels aimed at determining the aero-elastic properties of aircraft travelling at hypersonic speeds, including the FD-02, FD-03, and FD-07. The FD-02 is believed to be capable of generating a simulated range of Mach 3.5 to 8, while the FD-03 and FD-07 can simulate speeds of between Mach 5 to 10 and Mach 5 to 12 respectively.
Other Chinese government-owned hypersonic research institutes also exist, with the State Key Laboratory of Gas Dynamics being the most prominent. The institute has operated the JF-12 hypersonic wind tunnel – which is capable of simulating conditions at speeds up to Mach 9 – since 2012. Its new JF-22 hypersonic wind tunnel is expected to be ready for use in 2022 and is reportedly designed to be capable of simulating conditions for vehicles travelling at speeds of up to Mach 30 at altitudes between 40km (24.8miles) and 100km (62miles).
Testing for success
Just weeks after CASC’s Starry Sky-2 demonstration, the Institute of Mechanics at the government-run Chinese Academy of Sciences (IMCAS) also carried out atmospheric tests with three hypersonic vehicle models, with state-owned television channel CCTV 7 reporting that the tests were completed successfully.
According to CCTV7, the three test vehicles were carried to a high altitude by a specially designed balloon before being released and free-falling back to the surface at speeds in excess of Mach 1.
Although no official details were disclosed, visual analysis of CCTV footage revealed that the scale vehicle models – each around 6.5 feet (2 metres) long with a wingspan of about 5ft (1.5m) – adopted different aerodynamic configurations, with one featuring a delta form and single vertical tail fin (D18-1S), another with twin vertical fins (D18-2S) and the third with the vehicle body underslung beneath the wing (D18-3S).
While the test vehicles were unlikely to have achieved hypersonic speeds given their unpowered gravity launch method, but Chinese media reports have indicated that the demonstration was intended to gather comparative data on the vehicles’ flight performance characteristics when operating at speeds around the sound barrier.
“The reports seem to suggest that the tests had been designed to assess airframe performance around the sound barrier and low supersonic speeds,” said Zhu.
“This design approach may reflect that China is developing a hypersonic weapon capable of operating in a wide range of speeds,” he further explained. “For example, the vehicles could transit to the target area at hypersonic speeds which would minimise time for reaction, but slowing down in the terminal phase of the engagement to improve targeting accuracy.”
Powering hypersonic ambitions
China has also made significant strides in developing other enabling technologies, particularly in the realm of propulsion systems. For instance, IMCAS claimed in mid-2020 that it had successfully performed ground testing of an indigenous scramjet engine that lasted 600 seconds, according to an official statement that has since been removed from its website but reported widely by authoritative local media.
According to IMCAS, a prototype scramjet built by a team led by the Princeton-educated scientist Fan Xuejun – one of its top state academicians – broke the current world record of 210 seconds of continuous scramjet engine burn held by the United States with its X-51A waverider prototype in May 2013.
A scramjet had accelerated the X-51A to a final speed of Mach 5.1 (6,247km/h) before the craft’s fuel load was expended and glided to a programmed impact in the Pacific Ocean.
Local reports indicated that Fan, an expert in special fuels and engine cooling technologies, had also been instrumental in the construction of China’s first test facility for active cooling technologies in Beijing’s Huairou district. The district is also home to the Huairou Science City, which is expected to support the country’s leading public and private technology research and development organisations.
China is also developing turbine-based combined cycle (TBCC) engines that can be used during the launch and hypersonic phases of flight, although the challenges of thermal management have yet to be fully addressed.
However, it appears that the country has made significant strides on hypersonic-capable precooled aerospace engine technology with the influential Beihang University – previously known as the Beijing University of Aeronautics and Astronautics (BUAA) – leading the charge and securing a National Award for Excellence in Innovation nomination in May 2020.
Additionally, materials used to construct hypersonic weapons must be carefully selected to ensure that they resist deformation or warping due to the harsh aerothermal environment associated with extreme-speed flight within the atmosphere. Suitable materials for such demanding applications include carbon-based composite materials or ceramic metal composites (CMC), which would typically form part of the outer shell of the airframe to protect the rest of the vehicle during hypersonic transit and/or atmospheric re-entry.
China has certainly been actively involved in advanced materials research to meet a broad spectrum of commercial and military requirements, with recent announcements would indicate that work has progressed on high-temperature CMC materials. In this regard, Chinese researchers appear to have made some progress, with the state-owned newspaper Global Times reporting in April 2020 that a new heat-resistant material that can “endure temperatures of over 3,000 °C from friction caused by a Mach 5-20 flight within the atmosphere”.
by Jr Ng