Hypersonic weapon developments

Over the past decade, hypersonic technologies have become one of the most discussed developments related to modern warfare. At present, hypersonics are being actively developed both for tactical and strategic uses by most major military powers.

It is important to define what exactly hypersonic weapons are, as there is somewhat of a tendency to overuse the term, in marketing and for political purposes. Generally, hypersonic weapons are typically defined as those which have a speed of more than Mach 5 (five times the speed of sound). However, since this definition is overly-broad, as it would also include various other munitions, such as conventional ballistic missiles, which attain hypersonic speeds during their exoatmospheric part of flight. As such, the term is typically reserved for weapons capable of sustaining hypersonic speeds at endo-atmospheric altitudes, and which are capable of manoeuvring at such speeds. The majority of these fall into two primary camps – hypersonic glide vehicles (HGVs) and hypersonic cruise missiles (HCMs).

Russian efforts

For many years, Russia, China, and the United States have been working to develop hypersonic glide vehicles (HGV) to enhance their strategic capabilities. Notably, Russia already has up to 18 Avangard HGVs in operation within the 13th Orenburg Rocket Division, deployed as three regiments.

The Avangard system integrates an UR-100N UTTKh silo-based liquid-propellant ICBM (NATO classification: SS-19 Mod 3 Stiletto) with a new hypersonic glide vehicle, previously identified in open sources as ‘Object 4202’ and ‘15Yu71’. Developed by NPO Mashinostroyenia, the glider has reportedly undergone at least seven tests, the latest being on 26 December 2018. Unlike traditional re-entry vehicles used by ICBMs, the Avangard HGV re-enters the atmosphere earlier and transitions from a ballistic trajectory to gliding. Upon re-entry, it can reportedly reaches speeds of Mach 27, similar to conventional ICBM warheads, but this speed decreases rapidly during the long glide phase, due to the effects of atmospheric drag, and because the vehicle lacks its own propulsion. It is estimated that in the final phase of flight, its speed is reduced to around Mach 8-10.

The Avangard’s high speeds, coupled with its non-ballistic trajectory and manoeuvrability, make it difficult for current air and missile defence systems to intercept. Additionally, its controlled flight path allows for potentially more precise targeting, which could enable the future deployment of conventional precision-guided intercontinental-range warheads.

An intriguing aspect is how the Yasnensk site is outfitted with the UR-100N UTTKh, considering the last 30 missiles of this type in service are stationed at the Tatishchev launch site in the Saratov region, far from Yasnensk. Initially, the idea of relocating heavy liquid-propellant ICBMs seemed impractical. However, it appears that Russia acquired 30 stockpiled Stilettos from Ukraine between 2002-2004. These ICBMs were in good enough condition to remain operational until at least 2020 and beyond. It is plausible that 12-20 of these missiles were converted into Avangards and stored in empty R-36M2 ICBM silos.

Currently, the Avangard is seen as a temporary, transitional solution. The UR-100N UTTKh, with production ending in 1985, is old and has a finite lifespan. The future likely belongs to the RS-28 Sarmat heavy ICBM as the carrier for HGVs. On 1 September 2023, Russian news agency TASS quoted the Head of Roskosmos Yury Borisov as having entered service with the Russian Armed Forces. Due to its higher payload capacity (twice that of the UR-100N), the Sarmat could potentially carry two or three gliders simultaneously. Nonetheless, even when the RS-28 is more widely deployed, only a few are likely to be equipped with hypersonic gliders; the rest will carry conventional nuclear warheads, which are both cheaper and lighter — allowing the RS-28 to carry at least ten.

Given the current stage of anti-ballistic missile (ABM) system development, mass production and deployment of HGVs with nuclear payloads is seen as impractical. They are larger, heavier, and more expensive than standard re-entry vehicles and would result in a lower quantity of warheads carried. In the distant future, conventional hypersonic gliders capable of hitting global targets within around 30 minutes could be more valuable, but Russian defence industry is not yet prepared to produce the sophisticated guidance systems required for such high precision.

The only known HCM to have entered service is the Russian 3M22 Zircon (also sometimes written as ‘Tsirkon’), which has even seen use in the War in Ukraine. Reliable information about the missile remains scarce, and even the brief video recordings with its launches do not reveal much. What is clear is that after launching from the 3S14 vertical launcher, the missile is accelerated by a solid-propellant booster to supersonic speeds necessary to activate the ramjet or scramjet engine. Given the missile’s capability to reach speeds of Mach 8, it is likely that a scramjet engine is employed. However, in some corners it has been suggested that the Zircon’s cruising speed may be closer to Mach 4-5 (supersonic), with hypersonic speeds achieved during flight by activating a rocket motor to accelerate it further. Zircon’s range is estimated to be around 600 km. At the moment, there are versions of the missile for submarines and ships, and some information suggests the possible development of the land-based version. It is thought that there are at least two versions of the guidance system for Zircon – an active radar seeker variant for anti-ship applications, and a combined global navigation satellite system (GNSS) and inertial navigation system (INS) guided variant for engagement of ground targets.

Another operational hypersonic weapon in Russia’s arsenal is Kinzhal. This bears mentioning despite the fact that it is not considered to be a ‘true’ hypersonic weapon in the sense that it is neither an HGV nor HCM, but is rather an aeroballistic missile based on the 9М723 missile of the Iskander-M short-range ballistic missile (SRBM) system. Adapting the existing 9M723 missile for air launching is a logical move, as it requires relatively modest investment while fulfilling critical tasks: precision strikes on key enemy targets protected by layered air and missile defence systems. The missile’s maximum range remains the subject of debate, but it is confirmed to be at least 1000 km, as stated in official reports from one of the test launches. With a speed reaching Mach 10, the missile significantly reduces target engagement time, providing the Russian Armed Forces with a potent long-range tool for various conflicts. At an average speed of Mach 7, the missile can reach targets 1,000 km away in just six minutes. Kinzhal has been application is Russo-Ukrainian war is limited, but its known to be a hard target to intercept. At the same time, the myth of Kinzhal to be an invulnerable is also largely destroyed, as there are known cases of missile being intercepted by Patriot PAC-2 surface-to-air (SAM), despite the missile’s high terminal speed and use of penetration aids (a relative rarity for a tactical missile). At the moment, the only carrier of Kinzhal is the modified MiG-31K aircraft, but there is an ongoing discussion on adaptation of the missile for carriage by Tu-22M3 long-range bombers.

Russia also has few other projects in pipeline, such as the GZUR HCM and Klevok-D2 hypersonic artillery rocket. However, their questionable practicality in the context of the War in Ukraine is likely to slow down their development, as more immediate military priorities would be expected to take priority in terms of funding.

GZUR (some sources suggest the project is named ‘Gremlin’) is an HCM with a maximum flight speed of Mach 6 and range of over 1,000 km. Information on the project is relatively scarce, and it is assumed that GZUR is lighter and more compact than Zircon. Klevok-D2 is understood to be assumed a relatively light artillery rocket with range of about 100 km and speed of around Mach 5, based on the Hermes tactical missile. Again, concrete information on this project is relatively scarce, and given the problems the Hermes has already faced, it is perhaps too early to assess the prospects and capabilities of Klevok-D2 with any degree of certainty.

US programmes

US projects in the hypersonic domain included the well-known Advanced Hypersonic Weapon (AHW) and Hypersonic Technology Vehicle 2 (HTV-2). Since 2006, approximately USD 100 million of budget funds have been allocated to the AHW, while the HTV-2 has cost American taxpayers about USD 325 million since 2008. In total, the creation of flying testbeds, along with one partially successful and three unsuccessful tests, has amounted to USD 425 million. This is a significant expenditure, especially considering that ‘cost-free’ carrier rockets such as the Minotaur IV and STARS IV (special modifications of the decommissioned IBM LGM-118A Peacekeeper and UGM-27 Polaris, respectively) have been used for launches. These projects were initially fairly experimental in nature.

Since 2019, the Department of Defense (DoD) has invested over USD 8 billion in hypersonic missile development programs. These initiatives encompass independent efforts by the Army, Navy, and Air Force to create hypersonic boost-glide missiles. Additionally, there are collaborative projects among DARPA, the Air Force, and the Navy focused on researching into HCMs. Various research programmes concerning missile components are also part of this extensive investment.

At the moment there are two live US R&D programmes in the HGV domain, one each by the US Army, and US Navy, along with a questionably live USAF programme. The Common Hypersonic Glide Body (C-HGB), a further development of AHW, became the basis for the Army’s Long-Range Hypersonic Weapon (LRHW; also dubbed ‘Dark Eagle’), the Navy’s Intermediate Range Conventional Prompt Strike (IR-CPS) and the USAF’s cancelled Hypersonic Conventional Strike Weapon (HCSW; pronounced ‘Hacksaw’). HTV-2 on the other hand became the basis for the Tactical Boost Glide (TBG), which resulted in the USAF’s AGM-183 Air-Launched Rapid Response Weapon (ARRW; pronounced ‘Arrow’) programme, which is currently in a state of uncertainty, with signs pointing to the programme being cancelled in 2023. However, following a further test in 2024, its ultimate fate is still not entirely clear.

The Army’s LRHW boost-glide missile is designed to be launched from the ground using mobile transporter-erector-launchers (TELs). An LRHW battery will include four TELs, eight missiles, and one operations centre. While most performance characteristics of the LRHW are classified, it has been publicly disclosed that its range exceeds 2,775 km. The LRHW program has completed successful flight tests of a prototype missile, though it has also encountered test failures in recent years. Several more flight tests, conducted in collaboration with the Navy, are scheduled through 2028. The Army’s initial plans were to deploy first prototype LRHW missiles in 2023, with two additional batteries expected to be fielded in 2025 and 2027. However, failures during tests have pushed fielding of the initial capability to 2025.

The Navy’s IR-CPS boost-glide missile will be effectively a sea-launched variant of LRHW, likewise carrying the C-HGB. Initially, the Navy planned to deploy the IR-CPS on Virginia class nuclear-powered submarines, using the Virginia Payload Module—a multi-missile launcher intended for newer versions of these submarines. To expedite deployment, the Navy now plans to first field the IR-CPS on existing Zumwalt class destroyers and subsequently develop launch capabilities for Virginia class submarines. While the specifications of the IR-CPS are classified, its range is expected to be similar to that of the Army’s LRHW, exceeding 2,775 km. The Navy’s version of the boost-glide missile is anticipated to take longer to develop than the Army’s version for several reasons. Initially, the development of the IR-CPS was tied to the timing of the Virginia Payload Module. Additionally, launching a missile from a submarine requires a ‘cold launch’, in which the missile is ejected from the launch tube by a gas generator before igniting its rocket motor. This process is more complex than the ‘hot launch’ used for ground-launched missiles such as the Army’s LRHW, where the missile ignites its rocket motor at launch and propels itself out of the launcher under its own power. The Navy plans to field initial capability IR-CPS missiles on Zumwalt class destroyers in 2025, and deploy full-capability missiles on Virginia class submarines by 2028.

The USAF’s ARRW HGV was being developed by Lockheed Martin, and intended to be launched from B-52 bombers, with potential plans to use additional launch platforms, such as B-1 bombers. Thus far the USAF has disclosed some technical details about the missile, including that it would have a range of at least 926 km, and its booster consisted of a single-stage solid rocket motor which was based on the ATACMS missile. The USAF gave clear indication that the programme would be cancelled in 2023. However, not long after it indicated that the programme’s fate would be decided in a final test in 2024. This last test launch of ARRW was conducted on 17 March 2024, but at the time of writing, it was still unclear if the test was successful and what (if any) further plans exist for ARRW’s continued development.

A further US HGV effort exists in the form of the Operational Fires (OpFires) project. Development of the system began in 2017 as part of a joint programme between DARPA and the US Army. While the official range of the glide vehicle is undisclosed, as an intermediate-range weapon it is estimated to be around 1,600-1,800 km. This would effectively mean it occupies the range niche below LRHW, and conceptually intended to be lower-cost and more numerous. The OpFires system features a two-stage solid-fuel booster design, and is planned to use the same TBG-derived HGV as that used for ARRW. The speed of the weapon has been stated to exceed Mach 5, with unofficial sources suggesting that the glide vehicle’s speed ranges between Mach 6.5 and Mach 8. Despite at least one successful flight test in 2022, there is relatively little information on the current status of the programme.

In terms of US HCM programmes, since 2014, DARPA has been funding research into scramjets under the Hypersonic Air-Breathing Weapon Concept (HAWC) programme. As an outcome of these research efforts, the USAF and US Navy are respectively working on the Hypersonic Attack Cruise Missile (HACM) and Offensive Anti-Surface Warfare (OASuW) Increment 2, commonly known as the Hypersonic Air-Launched OASuW (HALO) programme. At present, concrete information on either of these projects in open sources is very limited.

The USAF plans to conduct 13 tests of the Hypersonic Attack Cruise Missile (HACM) between October 2024 and March 2027. A production decision will follow if the project proves successful. Raytheon serves as the prime contractor for the HACM, while Northrop Grumman is responsible for developing its scramjet engine. Less is known about the progress of the OASuW Inc 2 programme, which seeks to develop a scramjet-equipped cruise missile for the anti-ship role. Despite ‘hypersonic’ being part of HALO’s name, officials have indicated that it may not necessarily attain such speeds. According to Rear Admiral Stephen Tedford, Program Executive Officer for Unmanned Aviation and Strike Weapons at Naval Air Systems Command, HALO would probably be “in the high Mach 4 plus category as far as its peak speed.” At present, the US Navy is seeking a boost in funding for research, development, testing, and evaluation of HALO.

China and other international endeavours

Work on HGVs in China has been conducted in a fairly secretive manner. Most of the available information has been based on information coming from US intelligence agencies, which makes detailed analysis difficult. Some US sources even consider China to be the leader in the ‘hypersonic race’ at the moment.

What is known is that China conducted numerous tests of the DF-ZF HGV starting from 2014 and that the system probably became operational from 2019. The DF-ZF glider is used as the warhead delivery component of the DF-17 medium-range ballistic missile (MRBM), with a range estimated at around 1,800-2,500 km. The system is understood to have anti-ship applications, and to be capable of carrying conventional or nuclear warheads. Another Chinese ballistic missile, which is also thought to employ an HGV as the warhead component is the DF-27. Its range is assumed to be around 5,000-8000 km, and it thought likely to also be intended for the anti-ship role. Technically, it is possible that DF-ZF could potentially also be used with other Chinese ICMBs, such as DF-31 or DF-41.

While information on its HGV efforts is relatively scarce, even less is known regarding other Chinese hypersonic endeavours, such as HCMs. However, it is probably that the country is conducting at least some highly secretive work in such directions.

Elsewhere, France and India are also known to be conducting some experimental HGV tests, with respective examples being VMaX and Project Dhavani. However, at the moment these programmes lag far behind their counterparts in China, Russia and the USA. In terms of other efforts in the hypersonic field, France is developing the Air-Sol Nucléaire de 4ème Génération (ASN4G) nuclear-tipped air-launched HCM, as the eventual successor to France’s still in development Air-Sol Moyenne Portée Amélioré-Rénové (ASMPA-R). ASN4G is panned to be part of France’s airborne nuclear deterrent after 2030, to be carried by the Rafale fighter aircraft.

Closing thoughts

Hypersonic technologies continue to be in the focus and such countries as China, Russia and USA are considered to be leaders in development and deployment of these technologies. China and Russia were first to deploy hypersonic capabilities, largely they prioritised their importance, as well as taking a somewhat simpler approach to developing them. For instance, Russia demonstrated flexibility with their idea to adapt Iskander-M SRBMs as aeroballistic missiles in the development of Kinzhal.

US efforts have taken a somewhat more complex approach, for instance through developing HGVs capable of conducting long-range precision strikes with a conventional warhead. Despite this, in the long run, the conventional hypersonic strike capabilities, which the US is investing its time and resources into, have the potential to become much more significant game-changers on the real-world battlefield. While nuclear-capable systems such as Avangard provide strategic deterrent capabilities, it is widely hoped that such weapons will never be employed. By contrast, US efforts have coalesced around weapons which would be more likely to see actual use.

Leonid Nersisyan is a defence analyst and freelance author who has written for various publications in the defence and aerospace sphere, as well as a business development director at Bootech.