The United States has actively pursued the development of hypersonic weapons
manoeuvring weapons that fly at speeds of at least Mach 5—as a part of its conventional prompt global strike program since the early 2000s.
In recent years, the United States has focused such efforts on developing hypersonic glide vehicles, which are launched from a rocket before gliding to a target, and hypersonic cruise missiles, which are powered by high-speed, air-breathing engines during flight. As Vice Chairman of the Joint Chiefs of Staff and former Commander of U.S. Strategic Command General John Hyten has stated, these weapons could enable “responsive, long-range, strike options against distant, defended, and/or time-critical threats [such as road-mobile missiles] when other forces are unavailable, denied access, or not preferred.” Critics, on the other hand, contend that hypersonic weapons lack defined mission requirements, contribute little to U.S. military capability, and are unnecessary for deterrence.
Although funding for these programs has been relatively restrained in the past, both the Pentagon and Congress have shown a growing interest in pursuing the development and near-term deployment of hypersonic systems. This is due, in part,
to advances in these technologies in Russia and China, leading to a heightened focus in the United States on the strategic threat posed by hypersonic flight. Open-source reporting indicates that both China and Russia have conducted numerous successful tests of hypersonic glide vehicles and likely fielded an operational capability.
Several countries are developing hypersonic weapons, which fly at speeds of at least Mach 5 (five times the speed of sound).
There are two primary categories of hypersonic weapons:
Hypersonic glide vehicles (HGV) are launched from a rocket before gliding to a
Hypersonic cruise missiles are powered by high-speed, air-breathing engines, or
“scramjets,” after acquiring their target.
Hypersonic weapons could challenge detection and defence due to their speed, manoeuvrability, and low altitude of flight.10 For example, terrestrial-based radar cannot detect hypersonic weapons until late in the weapon’s flight. The image below depicts the differences in terrestrial-based radar detection timelines for ballistic missiles versus hypersonic glide vehicles.
Source: CRS image based on an image in “Gliding missiles that fly faster than Mach 5 are coming,” The Economist, April 6, 2019, https://www.economist.com/science-and-technology/2019/04/06/gliding-missiles-that-flyfaster-than-mach-5-are-coming.
Although Russia has conducted research on hypersonic weapons technology since the 1980s,
It accelerated its efforts in response to U.S. missile defence deployments in both the United States and Europe, and in response to the U.S. withdrawal from the Anti-Ballistic Missile Treaty in2001. Detailing Russia’s concerns, President Putin stated that “the US is permitting constant, uncontrolled growth of the number of anti-ballistic missiles, improving their quality, and creating new missile launching areas. If we do not do something, eventually this will result in the complete devaluation of Russia’s nuclear potential. Meaning that all of our missiles could simply be intercepted.”
Russia thus seeks hypersonic weapons, which can manoeuvre as they approach
their targets, as an assured means of penetrating U.S. missile defences and restoring its sense of strategic stability.
According to Tong Zhao, a fellow at the Carnegie-Tsinghua Centre for Global Policy, “most experts argue that the most important reason to prioritise hypersonic technology development [inChina] is the necessity to counter specific security threats from increasingly sophisticated U.S. military technology,” such as U.S. regional missile defences. In particular, China’s pursuit of hypersonic weapons, like Russia’s, reflects a concern that U.S. hypersonic weapons could enable the United States to conduct a preemptive, decapitating strike on China’s nuclear arsenal and
supporting infrastructure. U.S. missile defence deployments could then limit China’s ability to conduct a retaliatory strike against the United States.
China has demonstrated a growing interest in Russian advances in hypersonic weapons technology, conducting flight tests of a hypersonic-glide vehicle (HGV) only days after Russia tested its own system.
Sources: Congressional Research Service (CRS)