Hypersonic missiles can travel at five times the speed of sound or greater, and can change their trajectory, making them nearly impossible to stop. Photo: Handout

Is it possible to stop or destroy a hypersonic missile coming at you at Mach 10? That’s faster than the weapons being fired at it … so then what?

Experts say it doesn’t matter what size of ship you’re on — even with no warhead, you’re going to be punished, and severely.

Such weapons pose vexing yet likely surmountable challenges to radar engineers, with some new ideas being pitched, Jane’s Information Group reported.

Hypersonic technology could propel ordnance to speeds in excess of Mach 5 and has been enthusiastically embraced by military planners and missile engineers.

China and Russia have taken a lead in this new arms race.

The Russian Aerospace Forces, for example, are understood to be introducing hypersonic weapons including the conventional and nuclear Kh-47M2 air-to-surface missile, which has a claimed speed of Mach 10, Jane’s reported.

Various hypersonic initiatives are ongoing, with the People’s Republic of China reportedly developing the DF-ZF glide vehicle, Russia’s NPO Mashinostroyeniya working on the 3M22 Zircon surface-to-surface missile, and each of the US military branches running a development program.

Hypersonic missiles pose challenges to radar designers due to their high velocities, manoeuvrability, and radar cross section, Jane’s reported.

While software controlling contemporary ground-based and naval air surveillance radars operates at enviable speeds, the velocities of hypersonic weapons can still cause issues.

For example, if a radar needs two seconds to detect and commence tracking a Kh-47M2, if flying at Mach 10, it would in that time have already travelled almost 7 kilometres, Jane’s reported.

Royal United Services Institute research fellow Justin Bronk told Air Force Technology in an interview that ballistic defence systems rely on the fact that the missiles, by their nature, follow a ballistic and therefore predictable trajectory.

“Once you introduce a hypersonic glide vehicle-type payload, it becomes capable of changing direction quite significantly, and changing its flight path,” he adds. “You’re then looking at something that no longer follows a predictable path.

“It should also be mentioned though that apart from the unproven ground-based interceptor (GBI) system that is being developed at vast expense in the US, there is currently no capability to intercept even standard ICBMs, which is basically just a factor of the fact that they come in so fast.”

Bronk points out that in the US at least, current ICBM missile defence is focused on shooting down one or two ICBMs from a rogue nation such as North Korea or Iran, and US GBI systems would be incapable of defending against the scale of Russia or China’s strategic arsenals, Air Force Technology reported.

Nuclear payloads can be placed on hypersonic missiles, but even if missiles don’t have a payload, the kinetic energy released on impact makes hypersonic weapons extremely destructive. This makes them particularly dangerous to ships, says Bronk.

“If you had a hypersonic missile directly hit a stern or a bow, then it goes straight
through the ship.”

“If you had a hypersonic missile directly hit a stern or a bow, then it goes straight through the ship. The Chinese DF-21D is designed basically as a carrier killer. Even without a warhead, if it were to come in at significantly above Mach 5 and manage to hit the deck of a supercarrier – it might not sink it, but it would certainly be a mission kill.”

According to Bronk there are concerns within the military and defence industries with technology such as advanced anti-stealth aircraft radar that defence is becoming overdeveloped compared to offence, Air Force Technology reported.

“But if you were to bring in, for example, hypersonic air-launch cruise missiles as a means of striking ground targets within a heavily defended airspace, you automatically move the balance of power back to favouring offence.”

DARPA, the Pentagon’s pet research agency, has begun soliciting proposals for Glide Breaker, its project to stop boost-glide vehicles that are lofted high into the atmosphere atop a ballistic missile, and then glide down to Earth, The National Interest reported.

The current exemplar is Russia’s Avangard, touted by Russian President Vladimir Putin as unstoppable by anti-missile defenses. The Avangard is lofted by a giant RS-28 Sarmat ICBM, and then glides down to its target at many times the speed of sound.

Stopping a hypersonic missile means an interceptor that can close distance and maneuver in flight to do it. Credit: DARPA.

According to C4ISR.net, getting an interceptor to speed to hit a hypersonic weapon like Russia’s Avangard will take powerful engines, and on Feb. 10, Aerojet Rocketdyne announced that it had been selected by DARPA to develop the propulsion system for Glide Breaker. The contract is worth up to US$19.6 million.

“Advancing hypersonic technology is a national security imperative,” Eileen Drake, Aerojet Rocketdyne CEO and president, said in a statement. “Our team is proud to apply our decades of experience developing hypersonic and missile propulsion technologies to the Glide Breaker program.”

Aerojet has experience making both solid-fuel and air-breathing engines for hypersonic flight, and touted its prior experience with Boeing’s X-51A Waverider hypersonic demonstrator.

DARPA’s solicitation is light on unclassified details, though it says it wants “innovative solutions” to stop boost-glide vehicles.

That’s putting it mildly. If shooting down ballistic missiles is hard, then boost-glide vehicles is even harder.

For starters, the gliders don’t traverse outer space like an ICBM, but instead soar through the thin upper atmosphere, where they can achieve extremely high speeds while flying too low to be easily detected by early warning radars, The National Interest reported.

For another, while an ICBM warhead follows a predictable (and Mach 23) path as it descends through the atmosphere, a boost-glide vehicle — like a hobby glider — can maneuver, which make it much harder to an interceptor to hit.

Intercepting a ballistic missile with an anti-missile has been likened to “hitting a bullet with a bullet.” Imagine if the bullet were taking evasive action.

One way to think about intercepting a hypersonic missile is to imagine it as more like an aircraft than a conventional ballistic missile, said Thomas Karako, a senior fellow with the International Security Program and the director of the Missile Defense Project at the Center for Strategic and International Studies. 

“That’s why I’m banging the drum on the space sensor layer all the time,”  he told Defense One, referring to the Pentagon’s push for a new satellite constellation. “You have to see it before you can kill it.”

Says Karako, “It’s important to remember that these things, traveling at high speeds under a lot of thermal pressure, are far from invincible. They have a lot of vulnerabilities.” 

One might be able to bring together a mix of different approaches, including cyber or electronic warfare effects, to take one down, he added. 

To shoot down hypersonic missiles, the United States may use exploding warheads, reducing the need for precision. He cited the Arrow 2SM-6, and PAC-2 interceptors.

“Those aren’t hit-to-kill. They’re high explosive. It may be that you want to put a shotgun blast in front of [the hypersonic threat.] You may only need to do a little damage in this fancy control surface, to have an effect,” he said. 

Are hypersonics invincible? No, they’re not, but the cost of trying to defend against them may not be worth it in the end. A powerful combined offensive nuclear threat may be enough as a deterrence.