Futuristic weapons systems can grab our attention, excite our imagination—and cause a good deal of anxiety. But many of them—airborne lasers, particle beams—end up being ahead of their time or a flash in the pan. A new generation of hypersonic weapons is shaping up to be quite different. These weapons enable countries to strike targets before enemies can react and to defeat missile-defense systems through speed and maneuverability.
China and Russia already have these missiles, and other countries are developing them, including the U.S., Australia, France, Japan and India. These missiles are more maneuverable and harder to detect than earlier high-speed weapons, such as intercontinental ballistic missiles, or ICBMs, and can travel at more than five times the speed of sound, or Mach 5. This leap in technology is raising tough questions because the principles for when to use hypersonics have not been set and the ramifications of using them have not been thought through. We may be in for a period of instability until a strategy for dealing with them catches up with the reality that the weapons are here.
A Congressional Research Service report, Hypersonic Weapons: Background and Issues for Congress, published in August, highlights serious issues that could lead to an unintended escalation of a conflict. One is that the missiles’ short flight times leave little time for countries to decide how to respond. Another is that a key advantage, their unpredictable flight paths, may cause uncertainly about their intended targets, leading countries that aren’t being targeted to respond by mistake. Also, ambiguity about whether an incoming weapon is equipped with a conventional or nuclear warhead could trigger a nuclear response in error.
There are two types of hypersonics: low-flying cruise missiles and high-flying glide vehicle systems, which are boosted into the atmosphere by rockets and may exceed Mach 20. Glide vehicle systems have many features in common with nuclear-armed ballistic missiles, making them more problematic than cruise missiles from the standpoint of missile defense, crisis management, arms control and strategies to discourage attacks (known as strategic deterrence).
Last month the U.S. and Australia announced an agreement to build prototypes of hypersonic cruise missiles for their air forces. Neither the U.S. nor Australian defense departments will say when the missiles will be operational or how much the development program will cost. Australia wants to counter China and expand its ability to hit targets in the Indo-Pacific region. Meanwhile, the U.S. Navy and Army have been developing a glide vehicle that could be used with submarine-launched or mobile ground-based missiles. And the U.S. Air Force is pursuing its own glide vehicle that would be carried by bombers and launched from the air.
How did we get to this point where China and Russia have raced ahead in developing high-tech missiles and the U.S. is playing catch-up? China and Russia refuse to tolerate the idea that the U.S. might shoot down any missiles they launch, and a hypersonic weapon with a high-Mach speed and a great ability to maneuver would defeat any U.S. anti-missile system that depends on tracking inbound missiles flying on a predictable course. China and Russia have furiously opposed U.S. efforts over the past few decades to develop anti-missile systems, starting with President Reagan’s Star Wars plan.
More recently, the U.S. has deployed a missile-defense system in California and Alaska designed to intercept a small number of ICBMs from rogue nations such as North Korea and Iran that can’t be deterred by the fear of a devastating counterattack. The U.S. told China and Russia that the system was not designed to thwart their strike capabilities. Nevertheless, the U.S. deployment of the Terminal High Altitude Area Defense, or THAAD, system in South Korea in 2017 led to massive Chinese boycotts of South Korean products, and Chinese tourism to South Korea fell by nearly half that year.
Russia’s latest answer to U.S. anti-missile defenses is the Avangard hypersonic glide vehicle, which it declared operational last December. Russia claims the weapon boasts a velocity greater than Mach 20, and whether that’s true, its success shows that it overcame the extreme heat generated by high speeds. In previous tests, the control system for maneuvering the vehicle and aiming it at a target balked in the heat, according to Michal Fiszer, a military sciences professor at Collegium Civitas in Warsaw. In 2011, a U.S. hypersonic glide vehicle prototype crashed in the ocean after reportedly achieving Mach 20. The point for Russia is that it now can, at least on paper, evade the modest but expensive missile defenses the U.S. has fielded to protect itself, not against Russia but against rogue states.
China’s hypersonic glide weapon is the Dong Feng 17, which can reportedly reach Mach 10 and was showcased during a military parade last year (see photo). With a reported range of up to only 1,500 miles, the system is a theater-level threat in the Asia-Pacific region rather than an intercontinental threat. It’s capable of hitting targets in the first island chain, which form the eastern borders of the Yellow, East China and South China seas. Notably, South Korea and Japan are in its range; both countries are covered by missile-defense systems. Taiwan is also in its range.
Controlling its Hinterland
China has been cagey about whether there will be a nuclear version of the DF-17. Disturbing propaganda videos out of China seem to suggest that it may equip its hypersonic weapons with a nuclear payload, even against an aircraft carrier task force. Nevertheless, conventionally armed DF-17 weapons are clearly designed for enemies in what China deems its proper sphere that are protected by missile-defense systems. China views hypersonic weapons as part of its strategy to keep U.S. forces at arms-length from its perceived area of operations in a conflict.
The U.S. does not view the development of hypersonic weapons as existentially necessary, so it has been more circumspect in funding, testing and fielding such systems. This isn’t to say Pentagon war planners are not eager to add hypersonic weapons to their inventories. And military leaders seem more interested in countering China’s growing theater-level hypersonic capability than they are Russia’s strategy of making its arsenal a bigger deterrent to attempted attacks. In November, National Defense Magazine reported that Gen. Kenneth Wilsbach, commander of U.S. Pacific Air Forces, said he was “agnostic” about what sort of hypersonic weapon he needed “as long as I can hit the target with a weapon that is difficult to defend against.”
These programs highlight the different goals for hypersonic weapons among the world’s three military superpowers and potential adversaries. Russia and China are primarily interested in defeating U.S. missile-defense systems, either to maintain the ability of their nuclear arsenal to discourage an attack or to deny access to their declared sphere of influence. The U.S. is focused on what China and Russia are up to, but with its Prompt Global Strike program begun in 2003, the Pentagon initially pursued hypersonics so it could rapidly strike at difficult targets anywhere in the world with precision and without using nuclear weapons. These targets are generally ones beyond the reach of U.S. bases or aircraft carriers and include anti-satellite systems that could threaten U.S. satellites, concentrations of nuclear or chemical weapons, and key command-and-control facilities. North Korea and Iran might be candidates for such strikes today.
Congressional enthusiasm for funding hypersonic glide weapons waned after 2011 because of test failures, but now money is more available as potential enemies register their successes in the field. Congress authorized $512 million for the 2020 fiscal year for a conventional global strike program. For 2021, the Navy alone has requested $1 billion. Overall, the Defense Department requested $3.2 billion for 2021 for all hypersonic-related research, a one-year increase of $600 million.
Critics warn that concepts and rationales that seem so clear on paper may rapidly blur as hypersonic weapons enter service. Kingston Reif and Shannon Bugos, nuclear policy experts with the Arms Control Association in Washington, point out that the advantages cited by proponents of hypersonic weapons are often hyped. In particular, they dispute the idea that maneuvering glide vehicles offer any advantage over traditional ballistic missiles.
Russian and Chinese nuclear-armed ballistic and cruise missiles already have a high probability of evading U.S. missile defenses. And they note that while hypersonic glide vehicles and cruise missiles would be faster than the vast majority of current U.S. conventional missiles, they would not be faster than ICBMs. “Furthermore, while hypersonic weapons can fly at a lower altitude and may have greater maneuverability, hypersonic glide vehicles in particular could be more vulnerable to [ground-based] missile defenses due to the deacceleration of gliders caused by spending more time in the atmosphere,” says Reif.
Worries Over a Nuclear Response
More to the point, Kingston and Bugos say hypersonics pose a real danger of escalating a crisis. The U.S. is focused on developing non-nuclear-armed hypersonic systems, but if it launches a strike against a country, it risks a nuclear response if that country doesn’t realize it’s being attacked by weapons fitted with conventional warheads. “A conventional attack could lead to an inadvertent catastrophic escalation,” says Reif.
Indeed, since many of the rocket systems for boosting hypersonic gliders as they ascend are dual-use (nuclear and conventional) systems, how could the country being targeted know whether an incoming weapon was nuclear or conventional? The Congressional Research Office raised that question in a February report, Conventional Prompt Global Strike and Long-Range Ballistic Missiles: Background and Issues:
Some members of Congress and many analysts outside government have focused much of their criticism of the [Prompt Global Strike] concept on the potential that other nations might detect the launch of a U.S. [conventional] missile and conclude, mistakenly, that the U.S. had launched an attack with nuclear-armed missiles. Specifically, some argued that, if the U.S. were to launch these missiles during a conflict, nations with minimal satellite capabilities and launch-notification systems (such as China) or degraded launch-notification systems (such as Russia) could conclude that they were under attack with nuclear missiles. Further, because many possible targets lie south of Russia and China, and the U.S. has historically planned to launch its ballistic missiles over the North Pole, a conventionally armed long-range ballistic missile might fly over these two nations to strike its targets. For many minutes during their flight, these missiles might appear to be headed toward targets in these nations. The potential for misunderstanding is compounded by the short time of flight of these missiles, giving these nations little time to evaluate the event, assess the threat and respond with their own forces. Under such circumstances, critics claim that these nations may conclude they have no other option than to respond with their own nuclear weapons.
There’s a line from the 1975 movie “The Wind and the Lion” in which a U.S. ambassador wistfully says he would certainly love to see a certain so-and-so at bayonet point, but that it would be imprudent. The ability to strike targets deep in the enemy’s rear in less than an hour would be tempting. But it also would be imprudent because of the easy—possibly inevitable—opportunities for misinterpretation. If U.S. planners think they can strike with conventional missiles using the same method for delivering nuclear weapons and count on their intentions being read by the targeted country, they should disabuse themselves of that notion.
At the same time, hypersonic weapons have definite applications in striking otherwise difficult or impossible targets. Certainly, U.S. adversaries that are fielding them think so. If U.S. commanders also see an advantage in having them, even as a deterrent, then there is no reason why they shouldn’t, if only to understand them and figure out how to defeat them.
Ultimately, there are two motivations for developing and deploying hypersonic weapons. The first is to defeat missile-defense systems. While existing weapons may have this capability, major powers will inevitably improve their missile defenses. The second is to strike at difficult targets using conventional warheads and the kinetic energy of the high-speed weapons. However, this comes with the risk of miscalculation and nuclear escalation.
One possible way of mitigating such risk is to incorporate hypersonic weapons into arms-control efforts. The Carnegie Endowment for International Peace covers hypersonic weapons in an October paper outlining what a follow-up to the New Strategic Arms Reduction Treaty might look like. Faster and more capable strike weapons are likely to be a fact of life. Defense departments need to get a handle on the issues raised by these weapons before the technology outruns them.