Mach Beyond: The technical edge of hypersonic missiles

As multiple countries race to develop and deploy hypersonic missiles, questions remain about their cost-effectiveness and actual battlefield impact. This analysis explores the technical realities behind hypersonic glide vehicles and hypersonic cruise missiles, examining whether they can truly deliver on their promised capabilities.

Militaries around the world are clamouring to develop hypersonic missiles for conventional strike missions. The US, China, Japan, the UK, and France are all working on various hypersonic missile development programmes that are each at different stages – from concept studies to advanced experimental test launches, and reportedly in-service missiles. The Japanese MoD even indicates that its Hyper Velocity Gliding Projectile (HVGP) Block 1 – which is still undergoing tests – is in low-rate initial production.^[1] Russia reportedly deployed its 3M22 Zircon hypersonic cruise missile (HCM) against Ukraine in early February 2024, at least the remains of one of the missiles bears the designator 3M22. Russia’s Zircon strikes against Ukraine may mark the first use of hypersonic missiles in anger. Moscow has also deployed the Kh-47 Kinzhal, an aeroballistic missile that is technically hypersonic, but falls outside those considered here. China of course regularly parades the DF-17 with its DF-ZF large hypersonic glide vehicle (HGV), indicating that it is an in-service capability.^[2]

The US had had multiple hypersonic missile research & development (R&D) efforts to meet the needs of its various service branches. The Army’s main effort is the Long-Range Hypersonic Weapon (LRHW), a ground-launched HGV which is expected to be fielded by the Army’s Multi-Domain Task Forces in the next few years. In tandem with LRHW, the US Navy is developing the Intermediate Range Conventional Prompt Strike (IR-CPS), which is effectively a naval variant of LRHW, with both being based on the same Common Hypersonic Glide Body (C-HGB) design. The US Navy was also previously developing an air-launched near-hypersonic cruise missile, known as the Offensive Anti-Surface Warfare Increment 2 (OASuW Inc 2), also known as Hypersonic Air Launched Offensive (HALO), until the Navy cancelled the project in early April 2025, citing cost concerns and overall programme performance. The US Air Force (USAF) meanwhile is working on the Hypersonic Attack Cruise Missile (HACM), which as the name suggests, is an air-launched HCM.

Outside of the US, France is developing the ASN4G, a near-hypersonic cruise missile designed for nuclear payloads, and the UK has initiated its own hypersonic R&D programme in cooperation with the US and Australia with the stated aim of fielding a missile by 2030.

Many of these capabilities are nascent. With the exception of China’s DF-17 and Russia’s 3M22 Zircon and Avangard, none of them are currently in service; and yet, search LinkedIn for the phrase ‘hypersonic’ and you could be forgiven for thinking development in this area is more or less complete. Many articles and posts suggest that hypersonic missiles as a concept are completely new, that militaries discovered the key to hypersonic flight in 2010 and that they have since made rapid progress in developing them. Articles proclaim 2025 to be a breakthrough year for hypersonic technology, that hypersonic missiles are already revolutionising naval defence, and that the future of defence is hypersonic. With so much expectation placed on hypersonic missiles and their proclaimed war-winning capabilities, this article examines their underlying technology and operation in greater detail to get a sense of what these missiles are, and are not, going to do. But first, a little history.

Not a new frontier

“For approximately four decades, the hypersonic community had a difficult and somewhat dichotomous relationship with the military,” Dr Richard Hallion, Senior Adviser for Air and Space Issues, Directorate for Security, Counterintelligence and Special Programs Oversight wrote in 1998, for a volume titled ‘The Hypersonic Revolution; Case Studies in the History of Hypersonic Technology’. It is worth quoting Dr Hallion in full:

“Military officials concerned with force-structure requirements and combat operations recognized that hypersonics might have some merit, but the serious technological challenges (first involving rocket propulsion and re-entry protection and then, over time, more complex challenges, particularly air-breathing propulsion), and the pressing needs to develop more conventional fighters, bombers, and missiles to confront a highly aggressive Soviet state, often encouraged deferring work on hypersonics in favor of a “replacement strategy” emphasizing developing more traditional kinds of aircraft, missile, and other weapon systems.”^[3]

The volume including Dr Hallion’s contribution is 916 pages long and freely accessible. It charts attempts and studies designed to develop hypersonic vehicles and weapons from the early 1900s. It includes Eugene Sänger from Austria, who developed a concept for a rocket-propelled aircraft that he thought could reach speeds of Mach 13. Mach 13 refers to an object travelling at 13 times the speed of sound, which is 1,235 km/h at sea level. Sänger was suggesting that using a high lift-to-drag ratio, his craft could reach speeds of 16,000 km/h in 1934. This is not to say that Sänger was successful, but does stand as an indication of the length of time that there has been interest in hypersonic flight. Perhaps unsurprisingly, Nazi Germany worked on some rocket designs with a close to hypersonic flight, such as the A-4B, a derivative of the V-2 ballistic missile with gliding wings designed to increase its range. The A-4B was actually tested in 1945, reaching Mach 4 before one of its wings broke up.

It is safe to say that we are not living through a new frontier in hypersonic missiles. It is more accurately a period of hypersonic evolution. The drivers of this evolution are many and complex. Russian and Chinese air defence networks are advanced and capable, and the relative failure of Russia’s conventional cruise missiles to penetrate Ukraine’s air defence network indicates that those are weapons with potentially limited utility. It is also interesting to examine the change from Dr Hallion’s initial assessment in 1998, where the cost of hypersonic missiles was deemed so great, that it would detract from the pressing development of conventional platforms that were needed to confront the Soviet mass.

It could be argued that the current hypersonic evolution is driven by the inversion of that paradigm. Conventional platforms in the early 1990s were comparatively much cheaper than their modern day equivalents. An F-22 was estimated to cost around USD 135 million per aircraft in 2022, with the F-35 coming in at roughly USD 80 million per jet the same year (though previous lots cost more), and the future F-47 projected to cost “multiple hundreds of millions of dollars” per aircraft, according to former Secretary of the Air Force Frank Kendall speaking to Congress on 27 April 2022.^[4] For comparison, an F-16 was estimated to cost around USD 30 million in 2017, and USD 15 million in 1998.^[5] So, costs were increasing as Hallion and his team published their work on hypersonics, but they had not reached the present levels, whereby even the US Government is looking at fairly modest fleets of some of its future conventional capabilities.

So, if costs are limiting the ability to build mass, then MoDs have to ensure that their weapons at least reach the target and have the desired effect. In short, the cost of conventional platforms and weapons, combined with their potential vulnerabilities, have made the fielding of hypersonic missiles seem desirable. Added to this, the recent intensive development of key technologies that make them viable means that fielding them is now a realistic goal.

Defining hypersonic missiles

There are two primary types of hypersonic missile that are both relatively well-known, but it is worth a brief explanation: Hypersonic boost-glide vehicles (HGVs) are a type of missile that is boosted along a conventional ballistic trajectory before being released from a booster. The glide vehicle, which is typically unpowered, then continues to its target at hypersonic speeds using momentum, aerodynamics, and gravity, manoeuvring on its way. The second is air-breathing hypersonic cruise missiles (HCMs), which are similar in concept to a conventional cruise missile, albeit typically using a rocket booster to boost them to supersonic speeds, at which point a scramjet engine takes over to provide sustained thrust to hypersonic speeds for the rest of their flight.

Hypersonic missiles are often defined by their speed, which must exceed Mach 5 or 6,175 km/h. However, this is not all that defines them, they also need to be manoeuvrable and have specific flight profiles. Both types require air to function and manoeuvre, which differentiates them from ballistic missiles.

Hypersonic glide vehicles

This section focuses on the HGV, the technologies that they need, likely uses, and their limitations. Boost-glide vehicles are launched using a conventional rocket booster, which accelerates vertically and into an arc towards the target. At an altitude roughly between 40 km and 100 km, the glide vehicle detaches from the booster and descends back towards the Earth. It then begins to gradually lose speed, and performs a pull-up manoeuvre to properly orientate itself and gain equilibrium.^[6] The separation from the booster and pull-up manoeuvre both impart immense forces to the glide vehicle, the separation in particular requires a stable release or the vehicle risks an unstable flight.^[7] The post-separation portion if flight is known as the glide phase, and is worth examining how it differs from a conventional ballistic missile.

Conventional ballistic missiles are powered for the initial phase of their flight, in the same way that a boost glide vehicle is, they then proceed under the momentum imparted by the booster, with no further propulsion. In the case of tactical ballistic missiles (TBMs), short-range ballistic missiles (SRBMs) and to a slightly lesser extent medium-range ballistic missiles (MRBMs), the flight path is mostly shaped by gravity and air resistance. With longer-range classes such as intermediate-range ballistic missiles (IRBMs) and intercontinental ballistic missiles (ICBMs), air resistance plays a comparatively smaller role, as these classes spend a majority of their flight time in space, outside of the atmosphere. In any case, they also follow a similar, arcing, ballistic trajectory determined by gravity. You can visualise this by throwing a rock or ball high into the air – once it has left your hand, that ball follows a ballistic trajectory. Many classes of ballistic missiles will typically reach hypersonic speeds, however, as they are unable to change their flight path, their trajectory can be modelled, allowing them to be intercepted.

While interception is possible, this does not make it easy; Russia’s use of the 9M723 Iskander-M SRBM in Ukraine shows the limits of this theoretical framework. While Ukraine’s interception rates of cruise missiles are reportedly high – around 80% – its interception of 9M723 Iskander missiles is much lower. Over the course of two attacks in 2024, one in March and August, Ukraine intercepted just one of the 18 9M723s launched at it, and one of the 10 Kh-47 Kinzhals.^[8] It is one of the contentions of the US Congressional Budget Office, which has assessed that ballistic missiles would be as survivable as hypersonic missiles.^[9]

The design of the glide vehicle is very important, as once it has conducted the pull-up manoeuvre, it uses aerodynamic lift to continue its flight and extend its range. In the final portion of its flight, known as the terminal phase, the glide vehicle descends towards the target. The range and speed of a glide vehicle is shaped by the lift-to-drag ratio (this is simply the lift divided by drag), with the vehicle ideally able to generate sufficient lift to remain aerodynamically stable and capable of manoeuvre while taking on as little drag as possible from air resistance. This means that as the glide vehicle loses speed, it must drop to lower altitudes and thicker air that can provide enough lift to keep the missile flying – though this causes it to lose more speed as air resistance increases. So, the higher that the missile starts its descent glide, and the faster it flies, the further it can travel. A missile that releases at an altitude of around 47 km and travels at 6 km/s (Mach 17) could glide for more than 7,000 km, according to one computer simulation.^[10] It would take that simulated missile around 35 minutes to reach that range. As is the case for all missiles, any manoeuvres conducted during flight will use up available energy, reducing speed and overall range.

CONEMP leads the design

The final velocity of the boost phase becomes very important for an HGV, especially within the envisaged concepts of employment (CONEMP) that are driving their development. In short, the driving theory is that Russian and Chinese layered air defence and long-range strike capabilities would force the US to launch some of its effects outside of their reach. Those effects need to be fast to succeed. So, as the final velocity of the boost phase, along with release altitude, decides how far the glide vehicle will travel, it is critical that this element of the design functions properly.

However, very high speeds create design challenges for the vehicle itself. As the glide vehicle begins its glide phase and travels towards its target, extreme levels of heat must be dissipated without damaging the outer glide body.

Furthermore, the deceleration and formation of a plasma sheath around the missile body can interfere with radio frequency (RF) communication such as GPS, or sensors such as radar seekers, making accurate guidance of the missile extremely difficult. Although, it is worth noting that these challenges are far greater for terminally guided ballistic missiles, according to James Acton from the Carnegie Endowment for Peace.^[11]

“For a boost glide vehicle, this means that it will need a heat shield, typically made of carbon fibre or graphite, which can be quite heavy,” Dr Iain D. Boyd, Director of the Center for National Security Initiatives at the University of Colorado Boulder, told ESD during an interview. The materials used for heat shields are an ongoing area of research as different approaches are sought, but whatever material is used, it must be able to withstand ablation. “Ablation occurs because the air around the vehicle gets so hot that it breaks down chemically, and becomes oxygen which is incredibly corrosive as they oxidise carbon very rapidly,” Dr Boyd explained. “Ablation will physically change the shape of the heat shield, although some ceramic heat shields may provide better resistance to this effect,” he added.

Heat is not only a problem for the material that the missile is made of, it makes traditional guidance and target engagement difficult, too. Typical seekers such as optoelectronic TV or thermal seekers may not work under extreme heat, or would require specialised transparent housings allowing them to view the target area. Likewise radar would struggle to identify the target while the glide body is at high speeds. This drives reliance on accelerometers and gyroscopes, which must also be adjusted and improved to meet the extreme forces imparted during hypersonic flight.

There is one final challenge for the design of HGVs – which is also relevant to HCMs – and that is the warhead. Speaking on the current design challenges for hypersonics, Dr Boyd said, “Packaging is difficult because the vehicles are very slender, and there isn’t a lot of payload space. You can create more space, which leads to a bigger vehicle, which then costs more to launch.” Ultimately, the size of a glide vehicle is limited by the diameter of the booster, which in turn is limited by the launch platform. Consider the US Army’s LRHW, for instance, which must be launched from a dedicated transporter erector launcher (TEL), capable of fitting two LRHW launch containers side-by-side. Moreover, the geometry of a boost glide vehicle must be optimised to maximise the lift-to-drag ratio, which does not necessarily mean a lot of space for an explosive payload.

Much is often made of the kinetic energy of a hypersonic glide vehicle, which could be significant to destroy many targets. A 450 kg glide vehicle travelling at Mach 5 would transfer 661 megajoules of kinetic energy upon impact. This is enough energy to lift the UK’s 65,000 tonne Queen Elizabeth class aircraft carrier one metre off the ground. Kinetic energy alone might be enough to destroy a large, emplaced radar, such as some long-range or over-the-horizon designs. However, it would require a very precise hit and ideally would include an explosive payload to increase the damage against the target, guaranteeing the desired effect. As a result, the kinetic element of a hypersonic glide vehicle should not be overstated – it would require very high levels of accuracy to be an effective tool.

There are a range of hypersonic glide vehicle programmes underway around the world; these are summarised in Table 1.

 

Table 1: Hypersonic glide vehicle (HGV) programmes
Country	Project name	Capabilities	Status
China	DF-17 armed with DF-ZF HGV.	Believed to be nuclear and conventional capable. Top speed of Mach 10 and range of 2,500 km.	In service.
France	V-MAX[12]	Testbed, achieved speeds greater than Mach 5.	In trials and development.
Japan	Hyper Velocity Gliding Projectile	Conventional warhead with a range of 500-900 km for Block 1.	In development.
Russia	Avangard	Nuclear and conventional warhead capable. Top speed of around Mach 20 and range exceeding 6,000 km.	In service.
USA	LRHW/IR-CPS (C-HGB)	Range exceeding 2,700 km (est.).	Due to enter service in next few years.

Hypersonic cruise missiles

While HGVs seek to maximise speed and manoeuvrability to reach their target, relying on the inability of air defence systems to intercept the boost phase of most missiles. Their unpowered design means that they must leverage altitude and aerodynamics to attain the ranges necessary to meet force requirements. HCMs function differently, they are powered weapons, typically operating with a rocket booster to propel the missile to supersonic speeds, at which point they use a scramjet engine to reach hypersonic speeds and provide sustained thrust. Most tests appear to involve integration onto a jet aircraft, providing a boost to the initial starting speed of the launch, as well as representing the expected host platform for most weapons in this class. The Hypersonic Attack Cruise Missile (HACM), under development in the US, for example, is designed to be used by the F-15E Strike Eagle, and expected to be eventually integrated with other platforms including B-1 Lancer, B-2 Spirit, and B-52 Stratofortress. Under the SCIFiRE partnership, Australia also plans to operate HACM, to be launched from its F/A-18F Super Hornet aircraft, and the Royal Australian Air Force’s (RAAF’s) SCIFiRE page also suggests the weapon may come to be integrated with the country’s E/A-18G Growler, F-35A Lightning II, and P-8A Poseidon aircraft.[13]

HCMs, much like HGVs, must deal with a significant amount of heat. “With scramjets, the thermo-management problem is different from a boost glide vehicle: You have heat outside the vehicle and heat inside the vehicle from burning propellant. This is typically solved by lining the point between the engine and the body with special materials,” Dr Boyd explained. He added that an HCM travelling at Mach 5 experiences very different environmental factors to an HGV travelling at Mach 20. This means that while heat shielding may still be required on the missile’s exterior, it may not need to be as extensive or advanced as that fitted to an HGV.

The most important element of a hypersonic cruise missile is its engine. The typical approach is a supersonic combustion ramjet (scramjet) engine. Scramjets are a difficult technology to master. Pratt and Whitney, for instance, started work on a scramjet for hypersonic flight in the 1960s, revisiting it again in the 1980s as interest surged in space flight, and once more in 2001.^[14] Although flight tests have been conducted with a scramjet, they are prohibitively expensive; the X-51 Waverider which flew with scramjet engines from Pratt and Whitney Rocketdyne is estimated to have cost some USD 300 million, providing just four test vehicles for flights, three of which failed.

Scramjets work by compressing airflow at supersonic speeds into the engine where it is mixed with fuel like hydrogen or regular jet fuel and ignited. The ignited fuel generates an enormous amount of heat and highly pressured exhaust gasses that are passed through a nozzle at the rear of the engine generating propulsion. The airflow must be at supersonic speeds for the scramjet to work, which is why the missiles are generally designed to be launched from an aircraft already flying close to the speed of sound, with at least one rocket booster providing initial acceleration. The X-51 Waverider used the rocket booster from an ATACMS missile, which took it up to Mach 4.5 before the scramjet was ignited and the booster jettisoned.^[15]

Several HCM designs employ a missile body design known as a ‘waverider’, which has a very slender nose with the scramjet located underneath the missile body. As the flight speeds are lower than with HGVs, it is possible to fit optical systems and other sensors enabling the missiles to find their targets, Dr Boyd explained. Moreover, depending on the exact speed and altitude, can result in either no plasma sheath developing, or a plasma sheath with lower electron density than that of much faster vehicles such as HGVs.^[16] This should mean that RF communication could be possible depending on the missile’s height and speed. However, at the same time HCMs are usually smaller than HGVs – typically a few hundred kilogrammes – a good portion of which is taken up by the scramjet and its fuel. Like other missile designs, speed and range requirements lead to proportional increases in size, weight, and cost. So, the faster and further the missile is required to fly, the bigger and more expensive it will be. At least one of these facets is problematic when the cruise missile is designed to be launched from a relatively small fixed-wing jet. So, there is a compromise between range and speed, and a jet’s ability to carry and deploy the missile. This leads to ranges for cruise missiles generally in the 400–1,000 km region, with payloads of around 150 kg.

As a weapon system, HCMs are generally suited to engaging high-value targets such as naval vessels and potentially certain ground-based missile launchers if sufficiently accurate targeting data can be paired with seekers capable of locating their targets. HCMs offer very high speed strikes compared to conventional cruise missiles, which could prove very valuable in penetrating an adversary’s air defence network. However, the effects of those missiles getting through are not guaranteed. Known HCM programmes are summarised in Table 2.

Table 2: Hypersonic cruise missile (HCM) programmes
Country	Project name	Capabilities	Status
China	Lingyun-1	Unknown.	In development.
France	ASN4G	Near-hypersonic missile to be armed with a nuclear payload.	In development.
Russia	3M22 Zircon	Hypersonic anti-ship/land attack missile	In service.
South Korea	Hycore	Hypersonic missile for land, air, and sea with a range up to 1,000 km.	In development.
UK	HVX	Hypersonic demonstrator programme launched in 2022.	Demonstrator programme.
USA	HACM	Estimated to have a range of 500 km, with 150 kg payload.	In development.
USA	OASuW Inc 2 (HALO)	Near-hypersonic cruise missile with anti-ship warhead.	Cancelled.
USA	MoHAWK	Further testbed designed to improve hypersonic technologies.	Testbed.

Caution: Effects not guaranteed

During the 2003 Iraq War, US and coalition forces deployed 19,948 guided munitions from the air, according to data published by the Air Force Magazine.^[17] This constituted 68% of the munitions used, the majority of them were relatively close-range guided bombs. When US and allied forces conducted long-range strikes against Syrian facilities associated with chemical weapons in 2018, they launched a total of 103 missiles at just three targets.^[18] Russia has launched some 12,000 missiles and drones at Ukraine, according to figures released by Ukraine’s Air Force.^[19] All of these examples show that the number of missiles and guided munitions to achieve an effect at scale is much greater than a handful or the low hundreds. This is important for hypersonic missiles because there are two things that we can say about them with relative certainty, despite few actually being in service: First, they are expensive to design, to test, and to build, which means they will be expensive to use. Based on indications from the US Army and US Navy around the C-HGB, the Congressional Budget Office estimated that a procurement of 300 missiles would have a per missile cost of USD 41 million, and a total programme cost over 20 years of USD 17.9 billion.^[20] The challenge here is that this would represent just 300 missiles that may potentially only be suitable for engaging large fixed infrastructure and static targets.

Second, there is the issue of their payload. Russia has deployed glide bombs weighing up to 3,000 kg in Ukraine with guidance kits. These have proven effective in destroying singular, relatively large buildings with a single munition, even when they do not strike the building directly. However, with a relatively lower payload, a hypersonic strike may not deliver the same results from an imprecise strike. Even with a precise strike, the relative lack of payload may mean that the strike may not deliver the desired results in some tactical scenarios. Altogether, this means that hypersonic missile stocks are likely to be limited in number because of their cost, whilst only offering improved chances of penetrating air defences, and not necessarily guaranteeing the desired effect against their intended targets. In addition, if it is only possible to deploy relatively few hypersonic missiles because of their immense cost, a defender might choose not to worry about them, focusing instead on the bulk of conventional cruise and ballistic missiles being used at the same time.

In conclusion, missile strikes generally require some mass to achieve effects that are truly war-winning and difficult for an adversary to recover from. Hypersonic missiles are designed to address the problem of improved air defences, however, they are doing so at such immense cost that they may impose an opportunity cost on maintaining higher numbers of conventional capabilities, whilst also not necessarily guaranteeing effect on target.

Sam Cranny-Evans

 

^[1] US approves support for Japan’s hypersonic missile project

^[2] DF-17 | Missile Threat

^[3] Case Studies in the History of Hypersonic Technology

^[4] NGAD Price Per Tail Will More Than Double That of F-35

^[5] Your ultimate guide to the F-16 program (and why it’s so awesome)

^[6] (PDF) Hypersonic Missile Technology: A Comprehensive Analysis

^[7] Modeling the Performance of Hypersonic Boost-Glide Missiles

^[8] The future of stand-off weaponry, a tale of three approaches

^[9] U.S. Hypersonic Weapons and Alternatives

^[10] Modeling the Performance of Hypersonic Boost-Glide Missiles

^[11] Hypersonic Boost-Glide Weapons

^[12] Armées : la France a testé pour la première fois un planeur hypervéloce, capable de voler à plus de Mach 5

[13] https://www.airforce.gov.au/our-work/projects-and-programs/scifire-hypersonics

^[14] Hypersonic Missile Propulsion System

^[15] X-51A Waverider > Air Force > Fact Sheet Display

^[16] Plasma evolution mechanism and distribution characteristics of supersonic vehicles

^[17] The Gulf War II Air Campaign, by the Numbers

^[18] Syria air strikes: US and allies attack ‘chemical weapons sites’ – BBC News

^[19] Assessing Russian Firepower Strikes in Ukraine

^[20] U.S. Hypersonic Weapons and Alternatives