Hypersonic vehicle programmes have become a focus of media attention in the past decade. This has become more apparent with the Russo-Ukrainian War in 2022, with Russia utilising portions of its stock throughout its strategic bombing campaigns. As with other defence-related topics that receive outsized attention and interest, the popular discourse surrounding hypersonics has largely devolved into whether they represent “[t]he [f]uture of [w]arfare” or are “over-hyped” [source]. While undoubtedly essential questions, much of the nuance involved in this topic has been glossed over in favour of headline-catching claims.
Russia’s hypersonic vehicle programmes have received much attention due to its ongoing invasion of Ukraine. However, because of this, another major developer of hypersonic vehicles has largely been dismissed. The various Chinese hypersonic vehicle programmes are seemingly more developed and significantly more consequential for the future of Western-aligned interests in the Indo-Pacific. This article seeks to examine the different aspects of China’s hypersonic programme.
1.0: What does “Hypersonic” mean?
The etymology of hypersonic is fairly straightforward. As a prefix, hyper means “above” and “beyond” [source]. Sonic relates to sound, often the speed at which its waves travel [source]. The agreed-upon definition of hypersonic is speeds of Mach 5 and above, differentiating it from the more ‘tame’ supersonic classification [source]. The Mach system refers to speed as a multiple of the speed of sound, so Mach 5 is five times the speed of sound or around 1.7 kilometres per second. It complicated this definition because altitude and atmospheric conditions affect the speed of sound. However, the speed listed above broadly applies to this article.
Taken at face value, this definition would mean hypersonic weapons have existed since at least 1958, with the formal adoption by the Soviet Union of the R-7 [source]. Soviet engineers designed the R-7’s warhead to survive re-entry speeds of 6-7 kilometres per second, or roughly Mach 17.4 to 20.4 [source]. Ballistic missiles could be hypersonic if speed was the only consideration. However, speed is not the only defining characteristic of a hypersonic system. In a modern context, hypersonic platforms must be manoeuvrable in this state [source]. This prevents the inclusion of ICBMs and conventionally armed ballistic missiles, which follow ballistic trajectories. Chinese hypersonic vehicles abide by this definition.
1.1: A note about MARVs
Manoeuvrable reentry vehicles (MARVs) occupy an interesting position in that they are manoeuvrable whilst in hypersonic flight [source]. However, the initial ballistic trajectory of these warheads prevents the inclusion of MARVs as true hypersonic weapons. They follow ‘easily’ interceptable ballistic arcs and only become manoeuvrable in their terminal phase upon entering the atmosphere again [source]. Hypersonics typically fly on a flatter trajectory compared to traditional long-range ballistic missiles. In theory, hostile identification of an HGVs target would come too late to take adequate countermeasures [source]. Generally, the higher something is, the more easily detectable it is by ground-based radar systems. With hypersonic weapons,
2.0: Classification and Use of Hypersonic Vehicles
Hypersonic vehicles (HV) are programs developed explicitly to achieve the above definition of hypersonic. HV’s come in two primary forms.
2.1: Hypersonic Glide Vehicles
Hypersonic glide vehicles (HGV), also called hypersonic boost-glide vehicles, refers to a modular payload on top of a ballistic missile or rocket booster [source]. The missile or rocket would reach a sufficient altitude at hypersonic speed and release its HGV payload. This would then glide (hence the name) onto the target. The gliding aspect shows insufficient propulsion on the HV itself to speed up it to acceptable speeds. This (theoretically) allows for greater payloads at the cost of manoeuvrability compared to alternatives. However, HGVs remain highly manoeuvrable [source].
2.2: Hypersonic Cruise Missiles
Similar to HGVs, Hypersonic cruise missiles (HCM) are initially launched as a payload on top of a rocket booster [source]. Upon reaching near hypersonic speeds, the HCM detaches. It will proceed to breach the hypersonic threshold through an onboard engine called a scramjet (or ramjet) [source]. Scramjets, or Supersonic Combustion Ramjets, operate by utilizing oxygen passing through the airframe to ignite the fuel, thus creating thrust [source]. They differ from traditional jet turbine engines because they rely on the vehicle’s speed to compress air in front of it. Traditional turbine engines use fan blades found within the engine to achieve the same [source].
3.0: Employment and Rationale for Hypersonic Vehicles
Because of the speed and low flight profile that defines HVs, military staff officers see them as rapid-response weapons. When time is the question, hypersonics offer an answer. HVs are designed to attack high-value targets of opportunity. This includes enemy command sites, logistical depots, or, specifically in a Chinese context, American and allied naval fleets operating in and around the South China Sea. Moreover, the characteristics described above enable HVs to operate in contested environments. Traditional cruise missiles, manned and unmanned aircraft cannot offer the same capabilities [source].
These areas, known as A2/AD — anti-access/area denial — are cornerstones of modern anti-aircraft doctrine. Theoretically, they prevent deep penetrative strikes into friendly territory on sensitive logistical, communication, and command hubs. This enables forces on the frontline to operate at peak efficiency [source]. Striking these targets has been a central focus of US doctrine since the origin of Airland Battle in the 1980s. It has enabled US success in its conventional wars since then, most notably the Gulf War [source]. HV’s are, therefore, a logical step in maintaining this doctrine in the heavily contested airspace great powers expect to fight in during a peer or near-peer war.
3.0: The Soft Factor
The prestige that comes with ownership of a hypersonic programme is also a driver of HV development. As the US Congressional Budget Office puts it, “[b]esides concern about potential adversaries’ A2/AD systems, another stated rationale for developing hypersonic missiles is the sense that the United States has fallen behind those adversaries in hypersonic missile technology” [source]. Countries such as Iran have boasted that they have created a “hypersonic ballistic missile” stating that such a development is “a big generational leap in the field of missiles” [source]. As explained previously, ballistic missiles do not qualify as HVs. However, the clout of owning this new ‘buzzword ‘hot’ technology overrides adherence to reality. This factor is an ill-defined but very real aspect behind the development of HV programmes.
Ultimately, the value of HVs comes from their speed and detectability, or lack thereof. Striking a time-sensitive target rapidly is the driving force behind these programmes. The targets may differ from country to country, but the mission does not.
4.0: Hypersonic Vehicle Design Considerations
Given these weapons’ immense speed and expected use, design considerations are an inescapable fact of any discussion of hypersonic programmes. Engineers must overcome material science and flight characteristic challenges. Since HVs will fly in the atmosphere, the issue comes from finding a suitable material that can withstand high temperatures. Suitable material must be rated for 1,400° to 2,000° Celcius (2,550° to 3,600° Fahrenheit) for long periods of time, as well as be insulated to protect sensitive electronics [source]. Furthermore, these materials must also be light enough to permit their use by aircraft [source]. HCM development is based on this latter point and is part of the reason why no examples have been adopted as of yet.
The SR-71’s development is an excellent example of similar material science issues. Expensive titanium, ironically sourced from the Soviet Union, was essential and necessary for Skunk Works’ development of the aircraft [source]. Even with this, the SR-71 required holes in its chassis to allow for thermal expansion and regularly leaked hazardous propellant onto the tarmac while it was fueled [source].
Flight models at this speed and temperature are sparse and underdeveloped. These factors further inflate the cost. The US Congressional Budget Office estimated that HVs would cost 33% more per unit than comparative (performance and mission profile-wise) ballistic missiles. Furthermore, ballistic missiles are a more mature technology, and thus more attractive to customers looking for rapid-strike capabilities [source]. All told, the technological hurdles in creating HVs remain immense [source]. It is not even certain the challenges are worth overcoming.
5.0: The Chinese Context
As many know, China is preparing for a confrontation over Taiwan. Their 2019 defence white paper, China’s National Defense in the New Era, explicitly states a principal goal of the Peoples Liberation Army (PLA), the armed wing of the ruling Chinese Communist Party (CCP), is to “oppose and contain “Taiwan independence”” [source]. Any action on this front would doubtless incur action from the US Navy and its allies. The PLA Navy (PLAN) is currently unequipped to handle this massive force in a surface engagement [source]. They have stated in the above document;
“Greater efforts have to be invested in military modernization to meet national security demands. The PLA still lags far behind the world’s leading militaries”[source]
In order to prevent the strangulation of China from the seas by the currently superior American and allied fleets located in the Pacific, another stated goal of the 2019 white paper, Chinese hypersonic programmes have been heavily subsidized [source]. Indeed, US analysts have characterized Chinese hypersonic development as a “kind of Manhattan Project” [source]. The running assumption in Western defence circles is that by developing these capabilities and using them to strike key forward bases during an invasion of Taiwan, such as Guam and Diego Garcia, China can present its ‘inevitable’ mission as a fait accompli. This would (ideally) prevent additional US responses to the region [source].
5.1: Chinese Technological Hurdles
While the precise details remain highly secretive, the US Air Force and a contracted private analytical firm, BluePath Labs, published a report in late 2022 that details the key technological areas necessary for expected HV development [source]. Chinese Hypersonic vehicle development requires these components to be mature (technologically speaking) to enable the deployment of HVs. Key areas, taken from open-source Chinese scientific literature, are as follows.
- “Overall Integrated Design Technology [总体技术],” referencing developments such as “[i]nterdisciplinary design optimization technology [多学科设计优化技术],” and External design and aerodynamic force numeric simulation technology [外形设计与气动力数值模拟技术]” [source]. In other words, making sure the various concurrent developments can work together within a given HV system.
- “Propulsion Technology [推进技术],” such as “Scramjet engine technology [超燃冲压发动机技术]” and “Endothermic hydrocarbon fuel technology [吸热型碳氢燃料技术]” [source].
- “Materials / Processing / Manufacturing Technology [材料/工艺/制造艺术],” including “Heat-resistant and thermal insulation materials [防热与隔热材料]” and Component joining, welding and sealing technology [部件连接、焊接与密封技术]” [source].
- “Testing and Verification Technology [试验验证技术],” ensuring that recent technological developments work as designed [source]. This includes “Hypersonic wind tunnel technology [高超声速风洞技术]” and Heat-resistant structural materials thermal environment simulation and testing technology [防热结构材料热环境模拟与试验技术],” among others [source].
- “Flight Navigation, Guidance, and Control Technology [飞行导航制导与控制技术] [source].” This involves the development of “Hypersonic remote strike weapon precision guidance and control technology [高超声速远程打击武器精确制导与控制技术]” and similar navigation/guidance features [source].
- “Flight Demonstration and Validation Technology [飞行演示验证技术]” is, as the name suggests, testing these developments in a fully finished HV [source]. This includes “Aerial launch technology [空中发射技术],” Ground launch technology [地面发射技术],” and “Hypersonic separation technology [高超声速分离技术]” [source].
The study found that starting in 2016, China has devoted extensive resources into hypersonic adjacent technologies, including scramjet development, “combined propulsion system technology” (for achieving higher maximum speeds in atmosphere) and “[e]xternal design and aerodynamic force numeric simulation technology” (i.e., materials science) [source][source]. These imply rapidly developing domestic capabilities to manufacture and field HV’s, which Chinese hypersonic testing to date largely confirms.
5.2: DF-ZF (WU-14)
The DF-ZF is a Chinese hypersonic boost-glide vehicle, produced by the China Aerospace Science Industry Corporation. Formally adopted in 2020, it was originally designated as the WU-14 [source]. The PLA developed the DF-ZF concurrently with its launcher, the road-mobile medium-range Dong Feng-17 (DF-17) [source][source]. Both were tested as early as 2014 [source][source]. Experts at the Missile Defence Advocacy Alliance (MDAA) estimate its range to be 1,930km (1,200 miles) [source]. It can reach “between Mach 5 and Mach 10” and is reportedly manoeuvrable during this state [source]. The short-range DF-11, DF-15, and medium-range DF-21 can also launch the DF-ZF [source]. A theorized additional launch platform is the DF-26 [source].
It is possible that the DF-5 ICBM can launch the DF-ZF, though this is speculation. On 16 September 2021, the Financial Times reported the successful launch of an HGV, which “flew through low orbit space before cruising down towards its target,” though it “missed its target by about two dozen miles” [source]. Asian Military Review asserts that the likely launch vehicle was a CZ-2C (Chang Zheng-2C), itself derived from the DF-5 ICBM [source]. While the payload is (as of the time of writing) unconfirmed, it is possible that it was the DF-ZF. If true, this could drastically alter the range estimations of the DF-ZF, as the HGV “circled the globe in Low-Earth Orbit” [source]. However, as noted previously, this is speculation by the author.
5.3: Xingkong-2 (Starry Sky-2)
The Xingkong-2 (trans. Starry Sky-2), also referred to as the Xing Kong-2, is a Chinese hypersonic cruise missile currently going through testing [source]. It utilises a unique form of hypersonic travel called “waverid[ing],” which involves generating consecutive shockwaves to generate lift [source]. Combined with its scramjet, this enables it to reach “above Mach 5.5” for prolonged periods [source]. Experts expect a range of 700-800 km/h [source]. By the mid-2020s, it is expected to be adopted as an anti-ship cruise missile [source].
To date, the Xingkong-2 has undergone several test missions, resulting in 400-600 seconds (during different tests) of continuous hypersonic flight in that time [source]. The journal Science asserts that during one test, the Xingkong-2 maintained Mach 6 for 400 seconds [source]. This implies a travel distance of approximately 823 km (511 miles) in just under seven minutes. For context, the most modern American Tomahawk cruise missiles have a range of 2,400 km (1,500 miles) but operate at subsonic speeds [source]. In order to make the same journey, a Tomahawk would fly for just under an hour at its maximum speed of 885 km/h (550 mph) [source].
One of the more interesting developments in China’s arsenal is the WZ-8, a high supersonic drone [source]. As part of the 2023 Discord Leaks by a US Air National Guardsman, documents that emerged online detailing the drone’s capabilities came to the public’s attention [source]. Reportedly, the WZ-8 has a maximum speed of Mach 3 and a flight ceiling of 30,000 metres (100,000 ft) [source]. The American National Geospatial-Intelligence Agency (NGA) [source] provided these figures. Chinese media asserts the WZ-8 is capable of Mach 6 and has an altitude ceiling of 48,000 metres (150,000 ft) [source]. It is currently based at Liuan Airfield in the province of Anhui, though alternative airfields are listed in the report, including Zhangzhou, Huian, Fuzhou Yixu and Dashuipo Airfields, in Henan, Fujian, Fujian, and Shandong provinces, respectively [source].
5.4.1: Inspiration From the Past
The WZ-8 is likely based on the Skunk Works Cold War-era D-21 drone, which was captured by the PLA after crashing in Yunnan province on 20 March 1971 [source]. Both have similar reconnaissance-oriented mission profiles [source]. Both require a ‘mothership’ from which to launch; for the D-21, this was the SR-71 and Y-12, while the WZ-8 likely launches from the H-6, a Chinese bomber [source].
While (likely) not a true HV, this represents an important step in developing Chinese hypersonic aircraft. Indeed, TSC Beijing, a leading titanium manufacturer, has created a 3D printing method to cut down the production time of a new class of high-speed aircraft by a factor of four [source]. It is possible that this airframe was created for the WZ-8. If true, this could show an interest in higher, possibly hypersonic speeds for the drone [source]. Defence experts have speculated about future scramjet introduction onto the WZ-8 [source].
Hypersonic weapons have the capability to upend the deterrence model that has characterised the Pax Americana [source]. The capabilities of HVs will be a driving force in weapons and doctrine development in the coming decades when more countries begin to field them. However, it is essential to note that weapons are only as capable as the hands that guide them. In the context of this article, Chinese hypersonic vehicles can only strike at American carriers in the Pacific only if they know the carrier’s location. The Pacific is immense, and HVs are far too expensive to be used in the same way the board game Battleship is played. Thus, intelligence, surveillance, and reconnaissance (ISR) capabilities are essential components in HV employment beyond targeting static locations.
China has yet to develop the same in-depth capabilities that characterise US ISR efforts, though they have been making substantial gains throughout the past four years [source]. Other countries with similar programmes, such as that seen with Russia’s conduct during their invasion of Ukraine, suffer because of their lack of ISR capabilities, leading to HVs hitting primarily civilian residences and infrastructure [source]. As shown previously, the cost of HVs should relegate them to hit high-value, time-sensitive targets. Russia could just have easily launched significantly cheaper cruise missiles in a saturation attack for the same result.
Moreover, traditional missile defences have proven themselves capable of tackling the threat of HVs [source]. In the opinion of this author, HVs will be highly valuable for targets of opportunity, but fail to be the revolution in military affairs (RIMA) that proponents claim it is. Chinese hypersonic vehicles are and will remain an important consideration for future American and allied force deployment in the Indo-Pacific.