Jun 14, 2023

Hypersonic Hype?

Hypersonic weapons have a mixed impact. On the strategic level, they might have stabilizing effects, but also create incentives for escalation. On the tactical level, they have major indirect impacts.

DOCUMENT DATE:  12 May, 2023  Kyiv Mayor Vitalii Klitschko shows a Kh-47 Kinzhal Russian hypersonic missile warhead, shot down by a Ukrainian Air Defence unit amid Russia's attack on Ukraine, at a compound of the Scientific Research Institute in Kyiv, Ukraine May 12, 2023
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Over the past year, the use of the “Kinzhal” missile by Russia in its war of aggression against Ukraine has put hypersonic weapons in the spotlight. With the ongoing war and rising tensions over Taiwan, questions regarding the impact of this new technology on international stability and military affairs have become more pressing.

What’s in a Name?

As the name suggests, strictly speaking, all weapons traveling at speeds greater than five times the speed of sound may be referred to as hypersonic weapons. In this sense, hypersonic weapons are nothing new and have existed as intercontinental ballistic missiles (ICBMs) since the Cold War. However, today’s talk of hypersonic weapons refers to attempts to combine the speed of ICBMs with the accuracy of cruise missiles.

This new generation of hypersonic systems comes in two forms: hypersonic cruise missiles and hypersonic glide vehicles. Hypersonic cruise missiles (HCM) are similar to conventional cruise missiles in that they are powered throughout the flight but differ in using scramjets as propulsion. The use of scramjets, together with a higher cruising altitude of 20 to 30 kilometers, allow HCMs to reach hypersonic speeds. In contrast, hypersonic glide vehicles (HGV) use booster rockets to reach heights of 40 to 100 kilometers. There, the HGV disconnects from the booster rocket and hurtles toward its target at hypersonic speeds. The United States, China, and Russia have HGV programs, the latter two already possessing operational systems.

China and Russia Lead the Way, the US Is Catching Up

Russia started research on hypersonic technologies in the 1980s. In 2002 Washington withdrew from the Anti-Ballistic Missile (ABM) Treaty and stationed new missile defense systems in the US and Europe. This evoked fears in Russia that the increase in missile defenses could make the US immune to a Russian second strike, rendering Russia defenseless to a US nuclear first strike. To remedy the situation, Russia accelerated efforts to develop nuclear-capable hypersonic weapons that could penetrate US defenses. Russia currently has one operational HGV, the “Avangard.”

The “Kinzhal” missile shot down over Ukraine is often depicted as a hypersonic weapon. However, it doesn’t fall into the HGV or the HCM category but instead resembles a maneuverable air-launched ballistic missile. As such, it doesn’t constitute a hypersonic weapon of the latest generation. In addition to the “Kinzhal” and the “Avangard,” Russia’s ship-based “Tsirkon” is the only operational HCM.

Like Russia, China is developing hypersonic weapons to ensure its nuclear second-strike capabilities. In addition, China has shown particular interest in anti-ship hypersonic missiles. These could allow the People’s Liberation Army to conduct anti-access/area denial (A2/AD) operations, preventing the US from assisting Taiwan. China currently fields two HGVs, the DF-17 and DF-ZF.

The US does not have any operational hypersonic weapons. However, its navy, army, and air force have advanced hypersonic weapon programs. The US air force expects its AGM-183 hypersonic missile to be operational by this fall. The navy is looking to deploy its “Conventional Prompt Strike” hypersonic missiles in 2025 (Sayler, 2025). The army’s development of hypersonic missiles runs under the “Long-Range Hypersonic Weapon” (LRHW) label. In 2022 the first brigade was equipped with LRHW prototypes.

Strategic Considerations and Impact on International Stability

The ability of hypersonic weapons to use their speed and maneuverability to evade existing missile defenses can generally increase international stability. Concerning Russia and China, this is mainly because nuclear-armed hypersonic missiles ensure the effectiveness of their second-strike capabilities, therefore disincentivizing first use. As for the US, conventionally-equipped hypersonic missiles increase the credibility of US deterrence and assurances toward allies.

At first, the assertion that conventional weapons could improve deterrence seems startling. Over the years, we have come to believe that only nuclear weapons can ensure deterrence. However, as the Prussian general and strategist Carl von Clausewitz noted, the military is the pawn of politics. Politics will ultimately still dictate why, how, and when we fight wars. Former US Secretary of State Henry Kissinger was among the first to acknowledge the importance of politics in the military with respect to deterrence in his 1956 essay “Force and Diplomacy in the Nuclear Age.” Even nearly 70 years later, the reciprocity between war and society will help us understand why the US will be unwilling to commit to nuclear war and the destruction of its society to protect a distant ally. Against this background, an over-dependency on nuclear weapons will undermine the credibility of deterrence. Hence, conventionally-armed hypersonic weapons will supplement existing conventional deterrence and further increase deterrence credibility.

Despite hypersonic weapons having a generally positive effect on international stability, this no longer holds once an acute crisis unfolds. During an acute crisis, hypersonic systems favor the offensive, creating incentives to escalate. The strengthening of the offensive is mainly due to the shortening of the “Observe-Orient-Decide-Act” (OODA) decision-making loop. Specifically, once a crisis arises, hypersonic weapons’ high speed and ability to evade defensive systems will mean decision-makers might have little time to respond to a suspected attack. In addition, the shorter OODA loop will likely lead to the decentralization of command to junior officers, further increasing the likelihood of a deadly miscalculation.

Besides shortening the OODA loop, hypersonic weapons might allow an adversary to strike strategic assets with greater ease. Even if the attacked is not fully disarmed, a “broken back” might force concessions as retaliation would inflict limited damage on the adversary while resulting in the complete annihilation of the initially attacked state. It, therefore, becomes clear that once an acute crisis unfolds, shorter OODA loops and the possibility of a “broken back” mean hypersonic weapons will favor the offensive, making escalation much more likely.

Tactical Implications

When it comes to tactical implications, especially the prospect of hypersonic weapons inflicting a “broken back” might initiate major changes in tactics. In recent decades, the US has relied on a relatively small number of military units. The underlying rationale was that these units could penetrate enemy territory and deliver strikes unscathed. However, this impunity is no longer assured if an adversary uses hypersonic weapons. Taiwan offers an illuminating example. If China were to invade the island, the US would rely on supercarrier strike groups to assist Taiwan. In response, China could attempt to block US access to Taiwan by conducting A2/AD operations with hypersonic weapons. Were China to incapacitate the US carriers, the US would suffer from a “broken back,” there being little to support Taiwan further.

In response to the novel threat stemming from hypersonic weapons, future militaries might deploy greater numbers of smaller, expendable military assets. A shift to greater numbers will be enabled by decreasing production and operating costs due to 3D printing and automation. In fact, this purported paradigm shift toward greater numbers is already seen in other domains of warfare. In Ukraine, Russia uses swarms of over 600 drones that merely cost $20,000 per unit. Although Ukraine has been largely successful in shooting down these drones, it does so using missiles costing between $120,000 and $500,000 each. This means that in the long run, the massive use of expendable systems could triumph over more expensive military equipment.

It can be seen as an irony of technological innovation that the move toward more expendable military systems, initiated as a reaction to hypersonic weapons, might decrease the tactical significance of the latter. Using expensive missiles to counter cheap weapon systems might not be continued economically when resources are limited. This is particularly concerning regarding hypersonic weapons, as their costs are substantially higher than other missiles. For example, the LRHW developed by the US army is estimated to cost $106 million per missile. On the other hand, Tomahawk cruise missiles cost approximately $1.4 million dollars.

Consequently, the combination of the shift to greater numbers and the high costs of hypersonic missiles will decrease the direct impact hypersonic weapons will have on the tactical sphere. Still, we must not forget that hypersonic missiles will have a substantial indirect impact on tactics by initiating a shift toward greater numbers. Moreover, hypersonic weapons might still be deployed for high-level strategic targets, impacting international stability.

On the strategic level, then, hypersonic weapons will likely have generally stabilizing effects, but create incentives for escalation once an acute crisis arises. On the tactical level, hypersonic weapons will have major indirect impacts. Those together with the high costs of hypersonic missiles will reduce the direct impact of hypersonic weapons on tactics. Russia’s war against Ukraine might provide further insights into the impact of hypersonic weapons and the key question: how to prevent war and preserve a stable peace.

Pablo. J. Mathis is a researcher at the Sen Foundation.

Joris Voorhoeve is the former minister of defense of the Netherlands.