Hypersonic weapons, which combine the speed of the fastest ballistic missiles with the manoeuvrability of cruise missiles, will enter the arsenals of China, Russia and the US over the next five years. Whether their arrival starts an action–reaction cycle in military spending or further weakens crisis stability may depend on whether the countries building these weapons can agree on ways to control their proliferation.
On 27 December 2019, Russia’s defence ministry announced that its Yasnensky Missile Division, based in the Orenburg region bordering Kazakhstan, had deployed a missile regiment armed for the first time with a hypersonic glide vehicle (HGV). Many additional countries – including Australia, China, France, Germany, India and the United States – are also developing hypersonic weapons for their potential to penetrate advanced missile-defence systems and threaten mobile missile launchers.
Russia and the US have the oldest research programmes focused on hypersonic technology, dating to the 1980s. Currently, China appears to have the largest and best funded research programme, with the most aerospace graduates produced by its universities, scientific publications on hypersonics, operational ground-test facilities, hypersonic tests performed and systems in prototype development. The amount China spends each year on research and development has not been publicly disclosed, but statements by US Department of Defense officials suggest that China is spending more per year than Russia, and also more than the US, which spends US$1–2 billion annually. China’s first HGV, the DF-17, is expected to become operational some time in 2020 and has the potential to function as a highly effective anti-access/area-denial weapon in the Western Pacific.
China’s first HGV, the DF-17, is expected to become operational some time in 2020 and has the potential to function as a highly effective anti-access/area-denial weapon in the Western Pacific.
Russia’s new weapon – called Avangard and referred to by NATO as the SS-19 Stiletto Mod 4 – replaces the typical ballistic re-entry vehicle at the tip of an SS-19 intercontinental ballistic missile (ICBM) with a glide vehicle carrying either a conventional or nuclear warhead. Once aloft, the HGV detaches from the missile and re-enters the atmosphere, gliding towards its target at speeds of Mach 5 (1.72 kilometres per second) or faster. Avangard has an average speed of approximately Mach 10 (3.43 km/s). The term ‘hypersonic weapon’ is sometimes used as a shorthand to refer to both HGVs and hypersonic cruise missiles, which are under development.
Speed and manoeuvrability
Hypersonic weapons are not notable because of their speed alone. Traditional ballistic missiles with ranges above 300 km and their re-entry vehicles also fly at hypersonic speeds, albeit in the vacuum of space. An intercontinental-range ballistic system has an initial speed of approximately Mach 17–20. HGVs differ because they spend most of their time gliding in the upper atmosphere, combining speed with manoeuvrability. The target of a traditional ballistic missile is largely predictable early in flight based upon its trajectory. Some re-entry vehicles have a limited capacity to change direction once detached from a ballistic missile, but HGVs can use aerodynamic forces to manoeuvre laterally to targets hundreds of kilometres away from the location indicated by the bearing of their initial launch.
HGVs also differ because of their flight altitude. Traditional ballistic missiles are fired into outer space – beyond the Kármán line at 100 km in altitude, which traditionally defines the boundary of the atmosphere – and their re-entry vehicles follow a long, arcing trajectory towards their target. Missile-defence systems can detect ICBMs from distances of 3,000–4,000 km. HGVs coast towards their targets in the stratosphere, 30–50 km above ground. This appreciably reduces the range at which ground-based radar can track incoming hypersonic weapons, giving rise to efforts to create airborne high-altitude or space-based infrared tracking systems that can observe hypersonic vehicles at greater ranges. Some prototype HGVs use a non-ballistic launch platform, meaning that they would not be readily detectable by overhead early-warning systems. This could delay identification of the source of the missile and disrupt decision-making in response to the missile detection.
If used tactically, hypersonics are significantly more capable than subsonic weapons. They are marginally better than conventionally armed intermediate-range ballistic missiles (IRBMs), which are currently part of China’s arsenal. Russia and the US do not possess IRBMs because they were prohibited by the 1987 Intermediate-Range Nuclear Forces (INF) Treaty, but may acquire them given the treaty’s dissolution last year. The proliferation of IRBMs or HGVs has the potential to threaten mobile ground-based nuclear forces that until now have been largely invulnerable to attack. This is because both weapons are fast enough to destroy mobile missile launchers during the short window of time when they stop to prepare to fire. If countries begin spending to modernise, expand and further defend their nuclear forces in response to hypersonic capabilities, it could instigate the kind of action–reaction security competition that necessitated the creation of arms-control agreements during the Cold War to restore strategic stability.
If used tactically, hypersonics are significantly more capable than subsonic weapons.
Works in progress
Avangard builds on a prototype tested in 1990 as part of the Albatros project, led by the NPO Mashinostroyeniya missile design bureau. Albatros was one of several projects begun in the 1980s with the goal of defeating then US president Ronald Reagan’s proposed missile shield, the Strategic Defense Initiative. The projects were curtailed after the fall of the Soviet Union. Russia resumed funding hypersonic and missile-defence projects after the dissolution of the Anti-Ballistic Missile (ABM) Treaty in June 2002.
The Soviet Union and the US agreed to the ABM Treaty in 1972 in order to avoid an action–reaction cycle in the development and deployment of offensive and defensive missile systems. This cycle risked undermining the notion of ‘mutually assured destruction’, which constrained a nuclear state from launching a first strike when it was certain that its territory would be struck in return. If the Soviet Union or the US developed reliable and widespread defensive measures against incoming ballistic missiles, it would encourage the other to introduce ever-greater numbers of ICBMs into their arsenal. To avoid this spiral, the treaty limited the number and deployment of interceptor missiles on each side. President George W. Bush announced the US would withdraw from the treaty three months after the 11 September 2001 terrorist attacks, citing concerns that continuing to abide by its restrictions made the country vulnerable to attack from Iran, Iraq or North Korea.
Russia is currently in the late stages of developing several projects in addition to Avangard. A hypersonic cruise missile, 3M22 Zircon, has reportedly been tested with propulsion by a rocket booster followed by a supersonic combustion ramjet (‘scramjet’) engine accelerating the missile to speeds exceeding Mach 8. A failed test of Burevestnik (SSC-X-9 Skyfall) – a subsonic nuclear-powered cruise missile with global range – at the Nenoksa testing range resulted in an August 2019 explosion and release of radiation that killed seven people. Poseidon/Status-6 (Kanyon) is an uninhabited nuclear-powered torpedo capable of delivering a large nuclear payload. The weapon would be highly survivable at the outset of a nuclear war and would serve as a ‘retaliatory counter-value weapon’, meaning that its nuclear payload would be delivered against cities or civilians, rather than military targets.
China’s DF-17 HGV, which is nearing operational readiness, will have a range of approximately 2,000 km and the ability to threaten US ships and bases in the Western Pacific. Washington is pursuing several hypersonic projects of its own at various stages of maturity. None of the projects are expected to produce an operational weapon before 2023. The US Army and US Navy are jointly funding the Common-Hypersonic Glide Body (C-HGB), developed at Sandia National Laboratories, which will be adapted to fit the needs of each military branch. The army will use the common glide body for its Long-Range Hypersonic Weapon and the navy for its Conventional Prompt Strike. The US Air Force is creating its own glider in the Air-Launched Rapid Response Weapon (ARRW).
Dual-capable weapons
Dual-capable weapons – including ballistic missiles, HGVs and hypersonic cruise missiles – can be configured to carry only conventional payloads, only nuclear payloads, or either one ambiguously. The existence of these weapons is itself destabilising unless states remove the ambiguity, declaring in advance and providing verification that certain weapons will carry only conventional or only nuclear warheads. If ambiguity remains, a target state, upon detecting an incoming missile, could infer that the payload is nuclear and respond in kind. This problem is exacerbated by the speed and manoeuvrability of HGVs and hypersonic cruise missiles, because they shorten the decision window following radar detection – increasing the risk of miscalculation or misperception – and because they leave doubts about their intended targets. The speed of ballistic weapons is already a threat to crisis stability, regardless of recent advances in hypersonics. If states begin using weapons that are more manoeuvrable, and in dual-use fashion, it will risk a return to the policy of launch-on-warning for retaliatory strikes (i.e., firing after the detection of an incoming missile, but before impact).
The US has stated that its hypersonic weapons will not use nuclear warheads. Russia’s Avangard will likely be used for nuclear weapons only. China has not declared how the DF-17 will be used. Depending on its maximum operating speed, a DF-17 launched from China’s eastern coast could reach all of South Korea and most of Japan within 12 minutes, which includes time for launch, separation of the glide vehicle and the slowing effect of the atmosphere during the HGV glide phase. At these speeds, it could reach US bases on Guam in 15 minutes. In the optimistic scenario in which the HGV is detected shortly after launch, decision-makers would have a few minutes to consider the nature of its payload. In a conflict between China and India, India could fear for the survivability of a large portion of its nuclear arsenal, making launch-on-warning yet more likely.
In China, the People’s Liberation Army Rocket Force (PLARF) is responsible for all land-based ballistic missiles and ground-launched cruise missiles, both conventional and nuclear. There are dangers for Beijing in locating dual-capable systems within a single PLARF brigade. If such a unit were targeted by a rival with a conventional attack, the intent of the attack could easily be misconstrued.
Outlook
By the mid-2020s, hypersonic weapons will likely enter the arsenals of China, Russia, the US and perhaps other countries amid renewed proliferation of other types of offensive and defensive weaponry. In an unwelcome confluence of events, hypersonic technology is maturing just as major Cold War arms-control treaties are being dismantled. The US announced its withdrawal from the INF Treaty on 2 August 2019, after almost a decade arguing that Russia’s development of a ground-launched cruise missile, the 9M729 (SSC-8 Screwdriver), breached the terms of the agreement. It was also keenly aware that China was not a signatory to the treaty, and has been free to deploy many of the ground-launched ballistic and cruise missiles that threaten US air and naval forces in the Western Pacific.
New START, the last major arms-control treaty still in force, was signed by the US and Russia in 2010 and caps the size and number of their nuclear warheads, ICBMs and submarine-launched ballistic missiles. The treaty will expire in February 2021, unless Washington and Moscow agree to an extension. Russia has suggested it is willing to do so, and the Russian foreign ministry has said that it considers Avangard to be bound by the treaty’s missile limitations. The Trump administration has been sending mixed signals about whether it supports renewal or creating new agreements to limit the proliferation of new types of weapons. China is unlikely to agree to any constraints on its ability to develop new weapons, even if they are destabilising.
It is unclear whether the unique tactical characteristics of hypersonic weapons – speed, manoeuvrability and the capability to penetrate all currently deployed missile shields – will give rise to a Cold War-style cycle of action and reaction among competing states. If this does occur, new arms-control initiatives could focus on limiting the most destabilising problems caused by the new weapons. For example, agreements could establish a system for on-site inspections to remove warhead ambiguity, limit the colocation of forces, ban hypersonic weapons from borders and coastlines in order to increase times to target, or prohibit the development of new types of hypersonic weapons or of weapons above certain speed thresholds. That these proposals seem politically unattainable today – alongside broader trends against all forms of arms control and towards great-power competition – suggests that the situation is as difficult as it was at the beginning of the 1980s.
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