A Mach 5 Arms Race? Welcome to Hypersonic Weapons 101

They travel many times faster than sound, and defending against them won't be easy. Oh, and by the way, the United States, Russia, China and India all want them. 

According to some analysts, the development of hypersonic weapons creates the conditions for a new arms race, and could risk nuclear escalation. Given that the course of hypersonic research has acknowledged both of these concerns, why have several countries started testing the weapons?

The United States is building hypersonics for two reasons. First, we want to kill people fast, without the messy danger of a global thermonuclear war. Second, we want to be able to punch through the defensive systems of peer competitors.

Unfortunately, these two justifications contradict one another. Given that China, Russia and even India appear on their way to similar systems, we should take care before letting the technology outpace the politics.

What Are Hypersonic Weapons?

The term “hypersonic” generally refers to a class of long-range precision strike weapons that travel at Mach 5 or better. This definition generally excludes such munitions as the LRLAP (long-range land attack projectile), fired by the Advanced Gun System, which can only travel sixty miles, as well as traditional cruise missiles such as the Tomahawk, which travel under the speed of sound.

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Medium-range, conventionally armed ballistic missiles with precision-guidance (such as those operated by China and Russia) are arguably hypersonic weapons. The United States doesn’t operate any of this type, but it provides effectively the same capability as that offered by new hypersonic systems.

Indeed, initial U.S. plans for hypersonic-capable systems concentrated on conventionally armed ballistic missiles, but concerns over attribution and identification (conventional missiles look a lot like nuclear missiles to Russia and China) have shifted attention in the direction of suborbital platforms, including cruise missiles.

The United States is working on the Advanced Hypersonic Weapon, a long-range, land-based glide vehicle that operates within the atmosphere in order to avoid the appearance of a ballistic missile. The United States has also done work on the X-51 “Waverider,” an air-launched, scramjet-powered vehicle capable of Mach 6.

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China’s hypersonic vehicle, the WU-14, appears geared toward defeating U.S. ballistic-missile defense systems. Approaching at high speed through a depressed trajectory, it would attempt to exploit a seam between ballistic missile and traditional air-defense capabilities. Russia is apparently working on an array of hypersonic systems, which would include air- and sea-launched missiles that could target land and naval targets.

Why Have Them?

For the United States, hypersonic vehicles promise the ability to kill anyone, anywhere, on short notice. This capability become a key goal of U.S. security policy with the rise of Al Qaeda in the late 1990s, and the failure of traditional weapons to decapitate the organization before it could launch the September 11 attacks. More recently, the United States has begun to explore how hypersonics could help break apart an A2/AD system, or destroy nuclear or chemical munitions in preemptive anticipation of a launch.

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Russia and China face different incentives. The Russians surely understand the appeal of decapitation, but they rarely have the same need to strike across the globe at a moment’s notice. Similarly, the Chinese tend to have more local concerns. The logic behind Chinese and Russian developments lies in the pursuit of anti-access capabilities, as well as the need to keep up with the Americans. Hypersonic strike vehicles could provide a potentially indefensible means of attacking American and allied military installations, as well as U.S. Navy ships at sea.

Is there a hypersonic arms race? Simply because three powers appear to be working along similar lines does not necessarily mean that they’re working against one another; technological imperatives can push everyone in the same direction. We should expect that their strategic interests will push development in different directions, even if the three countries watch each other warily.

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When Will They Come to the Battlefield?