The Hypersonic Threat

At the beginning of this year, North Korea claimed to have tested a hypersonic weapon. While doubts remain about the program’s technical maturity, the North Korean test fits a broader trend: hypersonics are no longer emerging technologies, but a key element of modern military arsenals. Their complexity and cost, alongside the potential for diffusion between American adversaries, necessitates a focus on hypersonics and counter-hypersonics in U.S. defense procurement. The Pentagon ought to recognize that investments today are critical, not simply to field a small number of nascent hypersonics, but to build the foundation for a long-term U.S. hypersonic weapons program.

Initial hypersonic development has taken decades partly because of deficient budgetary focus in the early 2010s but also given of the technical complexity hypersonic weapons entail. When an object moves at very high speeds – traveling at least a mile every second – friction-generated heat increases, demanding specific, durable materials that can survive these temperatures.

However, the sheer number of hypersonic programs in or near deployment demonstrates that the major powers have solved several daunting technical challenges. China has fielded a medium-range missile mounted hypersonic glide vehicle, the DF-ZF, since 2019, and is close to fielding an intercontinental ballistic missile mounted glide vehicle on the DF-21. Russia has employed two hypersonic weapons against Ukraine, the Zircon cruise missile and Kinzhal air-launched ballistic missile. India has several programs in advanced development stages, as does Japan. Iran allegedly has a medium-range hypersonic ballistic missile, the Fatteh-2. Although North Korean engineering has obvious gaps, its newfound relationship with Russia likely gives it access to advanced Russian military technology, making a North Korean hypersonic feasible within this decade.

The first generation of hypersonics has weak points. The Russian Kinzhal, for example, struggles to maneuver effectively given its relatively poor construction, while the Zircon slows down enough during its terminal phase for top-line Western missile defenses to intercept it. China’s hypersonics are likely for use against large, static targets, most notably valuable bases like Guam, but anti-ship ballistic missiles still have serious targeting issues.

The trouble is, hypersonics will improve quite rapidly as national militaries field and test them at scale. This has been true of almost every major military technology. The fighter aircraft and bombers of the 1920s and early 1930s were largely obsolete by the time the Second World War began. Polish investments in its high-wing fighter aircraft, for example, were obviated by 1939, when the Luftwaffe’s all-metal low-wing designs quickly gained air superiority. Similarly, the bomber technology of the 1930s, which the UK believed would serve as an insuperable deterrent against long-term aggression, could not conduct a strategic bombardment against Germany. Technology evolves – it is crucial not only to field an initially-viable weapon, but to guarantee uninterrupted development of newer, more modern variants over time.

For hypersonic attack, many heat-shielding problems will be solved by the 2030s, while new targeting methods will enable glide vehicles mounted on ballistic missiles to hit mobile targets. Moreover, although cost and sophistication will constrain hypersonic arsenals, a growing proportion of older weapons may well be devoted to nuclear delivery, increasing the stress on American and allied homeland missile defense systems.

This makes long-term hypersonic attack and defense crucial to U.S. strategy. The former has received far more public and Congressional support than the latter. In FY2025, the Pentagon requested nearly $7 billion for hypersonic weapons, two billion more than the previous fiscal year, and another $11 billion for long-range strike weapons that include hypersonic programs. By contrast, the Missile Defense Agency (MDA) requested slightly under $200 million for hypersonic interceptor funding. In 2023, the Congress demanded the MDA deploy an initial Glide Phase Interceptor (GPI) system, the most advanced and mature U.S. counter-hypersonic, by 2029, several years earlier than anticipated. MDA has awarded a $500 million contract to accelerate deployment.

There is, however, a serious risk that the Pentagon and Congress miss the crucial need for sustained hypersonic and counter-hypersonic funding. As hypersonic threats increase in sophistication in the 2020s, counter-hypersonic technology developed in the 2020s will become increasingly ineffective. The next defense budget should provide sustained support not only to offensive hypersonic deployment, but to long-term counter-hypersonic development and deployment as well.

The First Trump administration began a welcome shift in U.S. defense policy planning away from the unfocused concepts of its predecessor towards a paradigm of strategic competition. If the Second Trump administration is serious about this competition, its Defense Department must demand from the Congress sustained support for crucial technologies, most obviously hypersonics and counter-hypersonics, to ensure the United States retains a key deterrence advantage over China and its authoritarian partners. American adversaries understand the necessity of technological competition and are playing to win. Only strong leadership from the Executive on down can ensure the U.S. emerges in a sound military position by the end of the decade.

Seth Cropsey is president of Yorktown Institute. He served as a naval officer and deputy Undersecretary of the Navy and is the author of Mayday and Seablindness.