How Do Hypersonic Weapons Affect US Security?

July 19, 2021
airmen secure rapid response weapon under plane wingGiancarlo Casem, Air Force
Cameron Tracy
Kendall Fellow

The United States, Russia, and China are racing to develop and deploy hypersonic weapons—missiles that fly low-altitude trajectories at more than five times the speed of sound. Work on these weapons, which are commonly touted as a “revolutionary” addition to global arsenals, is driving a significant fraction of US defense spending—$3.2 billion in the most recent budget, which represents about 3% of US spending on defense research and development.

Despite lofty claims about their capabilities and necessity, it remains unclear how exactly these weapons will contribute to US security and what missions they will carry out. In Part 1 of this FAQ, we looked at how hypersonic weapons work and what they can (or cannot) do. Here we focus on the politics of these weapons, US hypersonic weapon policy, and the global hypersonic arms race.

1. How many hypersonic weapons does the United States have?

2. How does the United States test hypersonic weapons?

3. Who is leading the hypersonic arms race?

4. Will the US be left at a disadvantage if Russia and China develop better hypersonic weapons?

5. Will the Biden administration change course when it comes to hypersonic weapon development?

6. Alongside other threats like climate change and the COVID-19 pandemic, why should we worry about hypersonic weapons?

7. What role does the US defense industry play in the hypersonic arms race?

8. Could international treaties or agreements limit the development or use of hypersonic weapons?

1. How many hypersonic weapons does the United States have?

As of now, the United States has not deployed any hypersonic weapons. Despite testing a number of hypersonic vehicles as far back as the 1960s, the nation never saw a pressing need to deploy these weapons.

This has changed in recent decades. The United States currently has a number of hypersonic weapons under development, with many slated for deployment in the near future. These include the Army’s Long-Range Hypersonic Weapon (LRHW), the Navy’s Conventional Prompt Strike (CPS) weapon, and the Air Force’s Air-launched Rapid Response Weapon (ARRW) and Hypersonic Attack Cruise Missile (HACM). The Department of Defense intends to deploy these weapons quite soon. For example, the LRHW and ARRW are slated for deployment in the early 2020s, while deployment of the CPS weapon is planned for later this decade.

Other ongoing US programs, such as the Defense Advanced Research Projects Agency’s (DARPA) OpFires weapon, are oriented towards research and technology development, rather than eventual operational status.

The numbers in which US hypersonic weapons are to be deployed are not public. However, statements from defense officials hint that they could be quite large. Last year, the Director of Defense Research and Engineering for Modernization stated that the US was rushing to produce “hundreds” of hypersonic weapons. The National Security Advisor stated that the Navy would deploy these weapons on at least 69 ships, in addition to submarines.

2. How does the United States test hypersonic weapons?

Given the status of hypersonic weapons as a largely unproven, emerging technology, testing is a key part of current development efforts. The United States tests its weapon prototypes by a variety of means.

Testing of weapon components is often performed at laboratory and wind tunnel facilities. Accessing the extreme airflow speeds and temperatures encountered in hypersonic flight is difficult in a wind tunnel, so creative instruments have been developed to approximate these conditions. For example, arc jet facilities pass electric currents through air to heat it to extreme temperatures before sending it streaming towards a test component.

Yet high power tests of this sort can be sustained for only a short time, often on the order of seconds. And there exist few of these large, costly facilities. Thus, flight testing is a critical part of hypersonic weapon development.

The United States has flight tested hypersonic vehicles as far back as 1960s. In the past decade it has conducted several flight tests of hypersonic weapons that are slated for deployment in the coming years. These include launches from missile ranges in southern California, Hawaii, and southern Alaska. In all cases, these missiles were fired towards a test site on Kwajalein Atoll in the Marshall Islands.

Despite the number of tests conducted to date, the results remain mixed. Several recent test flights were aborted when missiles failed to properly launch or lost control during flight.

3. Who is leading the hypersonic arms race?

As of now, Russia and China have reportedly deployed one hypersonic weapon each. Russia’s Avangard and China’s DF-17 are both boost-glide vehicles, launched on the front of rocket boosters. Each nation is also developing and testing hypersonic cruise missiles.

The United States has six distinct hypersonic weapons in development, spread across the Air Force, Army, Navy, and the Defense Advanced Research Projects Agency (DARPA). These include both boost-glide and cruise missiles. Three of the boost-glide weapons are slated for deployment in the next few years.

Still, there is more to an arms race than the types and numbers of weapons in deployment or development. More important are the capabilities these weapons provide. Determination of which nation might be “leading” the race is difficult because each of the nations developing these weapons has different reasons for doing so, and different capabilities in mind.

The key concern for Russia is the ability to bypass US missile defenses. Russian President Putin has stated that his nation needs hypersonic weapons because US defenses capable of intercepting nuclear-armed weapons could weaken Russia’s ability to deter attacks.

China is motivated by similar concerns about missile defenses, but also appears to be interested in the technological prestige associated with this new weapons technology. Chinese researchers have published a great deal of their research in the open literature, and presented it widely at scientific conferences.

US justifications for hypersonic development have shifted over time. In the 2000s, these weapons were presented as a means of intercontinental attacks on terrorist groups with non-nuclear weapons whose flight paths differ from those of nuclear-armed ballistic missiles, and which are therefore less likely to inadvertently set off a nuclear exchange. The US use case for hypersonic weapons has since radically shifted to a focus on more local conflicts against technologically-advanced nations (for example, conflict with China in the South China Sea).

There will likely not be any clear “winner” of the hypersonic arms race, since those participating do not even agree on the goal.

4. Will the US be left at a disadvantage if Russia and China develop better hypersonic weapons?

This depends entirely on the value of the new capabilities (if any) that hypersonic weapons provide to the United States or other nations. Given the capabilities of ballistic missiles, which are currently deployed and are faster than hypersonic weapons, this value is likely to be much less than is commonly assumed.

Consider, for example, the purported ability of hypersonic weapons to bypass some missile defenses. This appears to motivate Russian and Chinese development, as the United States has been developing and deploying long-range, mid-course defensive systems for decades. In contrast, neither Russia nor China have extensively deployed systems capable of intercepting a fast, long-range ballistic missile. Thus, the ability to evade long-range defenses is of little strategic utility for the United States. When it comes to short-range, terminal defenses, hypersonic weapons are essentially slower versions of ballistic missiles equipped with maneuverable reentry vehicles (MaRVs). Again, they offer few notable new capabilities.

The precise capabilities that the United States hopes to gain from hypersonic weapon development remain unclear. The Department of Defense has yet to articulate a clear need for these weapons, or a mission that ballistic missiles—perhaps equipped with maneuverable reentry vehicles (MaRVs)—could not accomplish more cheaply and effectively.

In short, it is not clear what the United States would lose out on, in terms of capabilities, if it were to refrain from developing hypersonic weapons, regardless of whether or not adversaries have them. More generally, it is a mistake to think that the United States must match the weapon designs of its adversaries, as many such weapons (e.g., Russia’s bizarre nuclear-powered, nuclear-armed, unmanned underwater vehicle) would serve no purpose in US strategy.

5. Will the Biden administration change course when it comes to hypersonic weapon development?

So far, the Biden administration is poised to substantially increase funding for hypersonic weapons development.

Under the Trump administration, funding for these weapons increased year after year. For example, the 2020 budget dedicated $2.6 billion, followed by $3.2 billion in the 2021 budget.

The 2022 presidential budget proposal, the Biden administration’s first, argues for a further increase to $3.8 billion. This includes funding not only for development, but also to begin the process of purchasing these weapons from defense contractors. The proposal also adds a new hypersonic weapon to the Air Force’s development portfolio: the Hypersonic Attack Cruise Missile (HACM).

In short, rather than carefully and soberly reassessing the last administration’s outsized spending on hypersonic weapons, the Biden administration plans to increase spending on these missiles.

6. Alongside other threats like climate change and the COVID-19 pandemic, why should we worry about hypersonic weapons?

To be sure, climate change is a serious, global threat that humanity must confront. So too is the risk of future global pandemics, like the ongoing COVID-19 crisis.

Still, these are not the only threats the world faces. The risk of military conflict, particularly between the nuclear-armed nations currently engaged in the hypersonic arms race, is a persistent threat to global security and human wellbeing. Taking measures to slow or prevent arms racing is necessary to reduce the likelihood of such conflict, and to lessen the destructive results should it occur.

Moreover, efforts to reduce international military tensions could support work on other pressing threats to human security. Both climate change and pandemics are global challenges, and addressing them will require international cooperation. This sort of cooperation becomes much more difficult in times of military conflict. In addition, reductions in spending on new weapons systems would free up resources that could be applied to more pressing needs, like reducing emissions or pandemic response. The $3.8 billion the US plans to spend on hypersonic weapons development in the coming year would surely be useful for these purposes.

7. What role does the US defense industry play in the hypersonic arms race?

Defense contractors are at the forefront of US hypersonic weapon development. These range from major players like Boeing, Lockheed Martin, and Raytheon, to myriad smaller firms spread across the United States.

This work represents a major revenue source for the defense industry. For example, Lockheed Martin expects to make about $1.5 billion this year from hypersonic weapons work. With hypersonic weapons seen as a “growth market,” contractors are spending tens of millions on lobbying each year, encouraging continued and increased spending on these weapons.

8. Could international treaties or agreements limit the development or use of hypersonic weapons?

Arms control measures could certainly limit the deployment of hypersonic weapons. Treaties have historically limited the deployment of related missile technologies. For example, the Intermediate-Range Nuclear Forces (INF) Treaty halted US and Russian deployment of certain classes of ballistic and cruise missiles for decades, until both nations withdrew in 2019. If current diplomatic tensions were resolved, similar limitations on hypersonic missiles might be envisioned.

More proactively, arms control measures could address the ongoing development of these weapons. One proposal involves a ban on the testing of hypersonic weapons which, since these missiles are at an early stage of development, could effectively prevent their future use.

Yet any arms control agreement addressing these weapons will be challenging to negotiate and implement, in large part because the United States, Russia, and China are each developing these weapons for different purposes, with distinct uses in mind. For example, Russia’s development is motivated by concern about the capabilities of US missile defenses; Russian policymakers may not feel particularly threated by US hypersonic weapon development since Russia does not deploy mid-course defenses of the type that hypersonic weapons are likely to be most effective against.

Thus, Russia might be uninterested in trading limitations on Russian development of hypersonic weapons for similar limitations on US development of these weapons. Instead, Russia would likely press for limitations on US defensive systems, something the United States has long opposed.

In short, arms control measures could do a great deal to reduce the global security risks associated with the hypersonic arms race. But arms control efforts are unlikely to progress until policymakers come to a better understanding of what these weapons do and why each nation involved in the hypersonic arms race is pursuing them.