Hypersonic Weapons: Overhyped or Superweapons? - threats, challenges & has the USA fallen behind?

Hypersonic Weapons: Overhyped or Superweapons? - threats, challenges & has the USA fallen behind?

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New weapon systems have a way of capturing the public imagination. And so far as buzzwords that will send journalists in 2023 scrambling to the printing press, digital or otherwise, nothing except perhaps nuclear weapons beats the word "hypersonic". In early March Russia won media headlines when it fired a salvo of 6 of its air-launched hypersonic weapons, the Kinzhal, at Ukraine. With Ukraine's old Soviet air defences completely incapable of intercepting the threat, the headlines about the implications of this new Russian super weapon quickly proliferated. And in a feat of dramatically bad timing, the Russian attacks would be quickly followed by an American announcement.

After a series of failed tests the Airborne Rapid Response Weapon, or ARRW, was being cancelled. But opinions on just how much of an impact hypersonic weapons would have on the global strategic balance varied wildly. On one extreme there are those that describe hypersonics as some sort of unstoppable super weapons, tools that will make existing weapons, defences and platforms obsolete at a stroke. At the other there are those who are argue that hypersonic weapons change very little at all. And that at best they represent little more than an interesting science project, and a fantastic way to spend huge amounts of taxpayer money.

The reality of course probably sits somewhere between those two extremes. And so today I wanted to take a closer look at hypersonic weapons development and ask the question: where on the spectrum do these things sit between prestige project and game-changing weapon system? To do that I'm going to start with some of the very basics: what are hypersonic weapons, what are their advantages, and why do we have reasons to be scared of them? And having explained some of the reasons that these weapons are terrifying, I'll give you a lot of reasons that they aren't. That'll mean having a top level look at some of the engineering and cost challenges involved in manufacturing these systems. As well as asking difficult questions like: how would you actually use them in a useful way, and are they better than existing systems? Then I'll have a closer look at the question of hypersonic defence and also at some of the major national hypersonic programs.

I'm going to limit this to discussing Russia, the PRC and the USA simply for reasons of time. I'll then try to close out by answering that question of just what the introduction of these systems means for armed forces around the world. I'll add the obvious caveat here that a lot of information on this topic is restricted.

I can only work with what's been published in open source. So it's possible that countries out there have systems and defences we're not aware of. But in this format, I don't think it's worth speculating too much. The final caveat is that content here is deliberately simplified from a technical perspective. My focus is on the capabilities and implications of these weapon systems, I'll leave the details of how exactly they work to more qualified experts.

So let's start with a pretty important question. Beyond just being a really popular buzzword, what exactly is a hypersonic weapon? The word itself simply relates to speed, with the most common definition being that a hypersonic object is one travelling more than five times the speed of sound, Mach 5. Below the speed of sound you are subsonic. Cross the sound barrier but less than Mach 5, you are supersonic. Beyond Mach 5 you are hypersonic.

Now that doesn't translate cleanly into kilometre or mile per hour figures. The reason being that the speed of sound actually varies based on altitude and conditions. On one hand the air is less dense, there's less to push through, so you're going to face less atmospheric drag. But at the same time you've also moved the goal posts in terms of what speed qualifies. At 60,000 feet Mach 1 is actually slower than it was at sea level.

But when analysts are talking about hypersonic weapons, speed alone usually isn't enough. In most discussions of modern hypersonic weapons, it's not enough just to go really, really quickly, you need to be able to manoeuvre constantly while doing so. If you can't change your direction mid-flight then you don't qualify.

Remove that qualifier and militaries around the world have actually been deploying hypersonic weapons for the better part of 80 years in the form of ballistic missiles. A ballistic trajectory is illustrated on the right there in blue. And we normally associate this kind of thing with long-range nuclear weapons. Basically a ballistic missile will achieve range and speed to target by punching up and out of the atmosphere, travelling in space, and then dropping down on its target from above. And given how quickly you need to be travelling in order to do that, being hypersonic is basically inevitable. And so if the only thing you're concerned about is speed, Yuri Gagarin was actually a hypersonic payload.

Alan Shepard from the US would follow soon after, re-entering the atmosphere at again more than Mach 5. In fact you could even argue that the German V2 from the Second World War was technically a hypersonic weapon. This was a short-range ballistic missile that would cross Mach 5 during parts of its flight profile. And because at the time hypersonics were unstoppable war-winning super weapons, as opposed to over-complicated and over-costed devices to answer a problem that didn't really exist, Germany won the Second World War.

By some estimates, the German V2 program in terms of cost was in the same ballpark as the American Manhattan Project. So for the same investment, one side got the V2 and the other got the atomic bomb. I'll leave that one to the audience on who got a better deal. But to get back to being serious for a moment, a V2 wouldn't qualify as a modern hypersonic weapon.

Now as is often the case, there are some odd examples that complicate the comparison. In particular I'm talking here about MAnoeuvring Re-entry Vehicles, or MARVs. Now this is an older technology. Pershing II, which was an American system that included this technology, dates back to the 1980s. Basically what you do with a MARV is you fire a traditional ballistic trajectory, but then before you get back into the atmosphere you eject a re-entry vehicle from the rest of the rocket. And then once it gets back into the atmosphere that re-entry vehicle is capable of manoeuvring.

Whether that's using fins, ducts, or some other control surface. The Pershing II re-entry vehicle would execute a pull-up manoeuvre once it re-entered the atmosphere in order to shed some velocity. And then once it had slowed down it would use radar to scan the ground beneath it to make sure it was pointed at what it was originally meant to hit. Using the combination of some control surfaces and that radar, it would then adjust its course to make sure it hit roughly where it was aimed at. So here you have a weapon that is travelling at hypersonic speeds and it's also manoeuvring.

But it's only manoeuvring during that final phase and with some pretty heavy limitations on what sort of manoeuvring it can do. But you're not going to have the same control or range of movement that you might have with say for example, something that looks like a conventional aircraft. But MARVs fill a very important role in modern strategic thinking. Namely, they allow countries that don't have a proper hypersonic weapons program to claim that they have a hypersonic weapons program.

Recently for example, the Islamic Revolutionary Guards Corps of Iran announced that they had a hypersonic ballistic missile. Which if you've been paying attention is kind of funny as a statement, being hypersonic is just kind of what ballistic missiles do. But reportedly this is a two-stage solid-fuelled ballistic missile with a manoeuvring re-entry vehicle.

With the General quoted as saying, "I express confidently that the enemies will not be capable of developing a similar missile over many upcoming decades." In response to which I'll put up an image on the screen of a field manual from the 1980s for a two-stage solid-fuel ballistic missile with a manoeuvring re-entry vehicle. It's not an exact analogy but you get the picture, this is not exactly new technology. Instead the real deal when it comes to the hypersonic race is split into two categories: hypersonic glide vehicles and hypersonic cruise missiles. A Hypersonic Glide Vehicle, or HGV, is basically exactly what the name suggests. The known designs are un-powered gliding projectiles that nonetheless have some ability to control themselves and manoeuvre at very high speeds and high altitude.

What will normally happen is that something else will get a HGV to altitude and speed, usually some form of ballistic missile. And then using the immense amount of energy that it has built up in terms of both speed and altitude it will glide to its target, manoeuvring if necessary as it goes. A high altitude flight profile plus the considerable kick given by the launching ballistic missile means that these things can accomplish very high speeds. And while I say "high altitude", it's still a much lower altitude than a normal ballistic arc for something like an ICBM.

After all, an HGV can only manoeuvre in the atmosphere. Control surfaces only work if there's air for them to work on. If you're in a moving boat and you turn a rudder, well the boat is going to turn.

But put a rudder on the International Space Station in Earth orbit and you're not going to get yourself many results beyond a hearing for wasting taxpayer funds. Against many targets this flight profile is going to be considerably slower than just going up and down like a ballistic missile. But it has a range of other advantages too that we'll talk about in a bit. The other primary type of hypersonic weapon is the hypersonic cruise missile. This takes the ordinary concept of a cruise missile, a very long-range guided missile that you can yeet at things from very long distance, and just makes it go really, really fast.

Because of the very specific engines that most HCM designs use, like hypersonic glide vehicles they are usually going to need something else to get them up to a reasonable speed and altitude. That might be a rocket motor or it might be a launching aircraft. But from there there's a major difference, hypersonic cruise missiles are going to be powered throughout their entire flight. They are usually going to fly lower and slower, much lower and slower, than your average hypersonic glide vehicle, but because they're powered the entire way manoeuvring is going to impose less of a tax on them. Now being powered means you need an engine to power them, and one designed to fly at very, very high speeds.

For HGVs this isn't an issue, the rocket motor that launched the thing got it up to speed and then it just glides to its target, no engine required. But an HCM needs an engine, and building a rocket motor with the required endurance to operate within the atmosphere, yeah, that's not happening any time soon. And so most known HCM designs use air breathing engines. But they can't use traditional turbo jets, those engines (which you will have seen powering everything from military aircraft to passenger airliners) use a series of fan compressor blades to compress a bunch of air into the engine.

Then they ignite a bunch of fuel, super-heat it, and shoot the air out the back to generate propulsion. That doesn't really work at very high speeds. You no longer need the compression fan blades, because the air is going to be compressed just by the fact that you're ramming into it at very high speed.

So you ditch the fan blades entirely and simplify the engine. That improves performance at higher speeds, but decreases efficiency at lower velocities. You might be able to light a ramjet for example at subsonic speeds, but comparatively speaking it's going to be a pretty dog shit engine until you get up to higher velocities. But not too high, otherwise the engine efficiency starts to drop off again. So you are stuck redesigning the engine again into a supersonic combustion ramjet, or scramjet. Now in diagram form this looks like the simplest design.

It's the closest to just a straight metal tube with some shenanigans going on to allow combustion in the middle. So it's a great potential engine for something like a hypersonic cruise missile that might want to go very, very quickly. But while it's simple as a concept, the engineering challenges of actually building one are pretty immense. And again, the system only works if you're already going pretty fast. So you need something else to get you to velocity, and then after the engine lights you need to stay at velocity.

Just like some fish need to always be swimming forward in order to breathe through their gills in the ocean, a scramjet needs to keep moving through the air in order to breathe. Now I doubt Nemo is going to pull Mach 5 any time soon, but hopefully you get the picture. Turbo jets have existed throughout the jet age.

Ramjets were popular in a number of Soviet Cold War supersonic missile designs. But scramjets that can function for more than a few continuous minutes? Those are a relatively modern invention. But if you want to do powered in-atmosphere hypersonics, like really do powered in-atmosphere hypersonics, this is probably your engine. OK, so if that's the "what", let's move on to the "why". What purpose do hypersonic weapons serve, other than making for fantastic headlines and putting upward pressure on defence sector stock? And here the key factors are detection, responsiveness, and the ability to penetrate defences.

And that first point around detection and warning time, that's one of the most commonly cited advantages of hypersonic weapons. Because in order to do something about an incoming threat, whether that's trying to shoot it down or move or shelter the target, you need to see it coming first. And here it's the flight profile of hypersonic weapons that might give it advantages over alternatives like for example, ballistic missiles. This image here from the CSIS (although you can find other versions of it online) illustrates the problem quite well. And it allows me to make one of the most controversial statements I have ever made on this channel: the Earth is not flat. And when it comes to missile defence that matters, because the range of radar is usually limited by the curvature of the Earth.

I can make my sensor array as impressive as I want, it probably can't look directly through hundreds of kilometres of solid rock. And so the higher something flies, all else being equal, the further away I'm going to be able to detect it. For a traditional ballistic missile, that means detecting at potentially a very long range. But by staying much lower, our hypersonic glide vehicle is going to exploit that curvature of the earth for a much longer period of time. It may not get to a target as quickly as a ballistic missile, but if that's the set up we're talking about, I'm going to get much less warning regardless. The problem is even more acute when you are talking about hypersonic cruise missiles which are going to be flying lower again.

If you've invested heavily in filling your country with radars designed to detect ballistic threats, then this may represent a very unwelcome change for you as you may not see the new threats until it's far too late. Importantly however, this advantage only really applies compared to conventional ballistic missiles. Anyone who's seen cockpit footage from Ukraine will be aware of just how low human pilots or current cruise missiles can already fly. But compared to those conventional jets or conventional cruise missiles, time to target is the big difference. That's pretty logical. All else being equal, if you go faster you'll get to the same destination sooner. A conventional cruise missile moving at Mach 0.9

is going to be able to service a target at 100 miles in less than 10 minutes. Jack the speed up to Mach 15 using a hypersonic glide vehicle, make some accounting for the launch and descent process, and you might be servicing a target at 1,500 miles on the same time frame. Not only might that mean a chance to get your punch in first, it might mean that if a target is fleeting, only going to be available for a certain period of time, a hypersonic weapon might be able to hit it when a conventional option won't. Maybe you're trying to stop an enemy missile launcher from launching its payload, or maybe you get intelligence that an enemy general has stopped for coffee, a hypersonic missile might arrive while they're still trying to get his name written down on the cup, whereas a conventional weapon he's already going to be well on his way.

And all you're going to end up doing is explosively disassembling the barracks coffee machine. The third advantage, and the one that gets probably the most air time, is the fact that hypersonics present a very difficult challenge for missile defence systems. With the key here not just being their speed, or their low altitude flight, or their manoeuvrability, but rather the combination of all three. Ballistic missiles already travel incredibly quickly, faster in fact than hypersonic weapons as currently proposed. But because they're comparatively easy to detect taking that high trajectory, and because their path is relatively predictable, you can design a missile defence solution without building an interceptor fast enough to chase the ballistic missile warhead.

You can just put something in its path and intercept it. Something like an HGV is really going to mess with that particular equation. We've already discussed theoretically why you might not detect the weapon until much later in its flight. And US defence officials have outright admitted that existing terrestrial and space-based sensors are probably insufficient to detect and track hypersonic weapons.

Plus, even once you detect something like an HGV the interception challenge is significant. You can't just dump something in a predictable flight path, because the HGV can manoeuvre. And even relatively small manoeuvres are going to make interception far more difficult.

You are no longer just trying to hit a needle with another needle mid-flight. Now you are trying to hit a needle with another needle, while not knowing where the target needle is going to be until the last possible moment. Now as a general rule, an interceptor needs to have several times better performance than the target it's trying to intercept.

If a missile trying to shoot down a jet has inferior manoeuvrability, acceleration and speed, well, then a capable pilot with warning is going to evade it every time. I'm reminded here of the frustration of trying to use Mark 37 torpedoes in submarine simulators. The Mark 37 was a Cold War-era torpedo, it was guided, but it had a maximum speed I think of 26 knots.

That's obviously much slower than many surface warships, which meant for a lot of targets that if they were aware that a Mark 37 was being fired, they could evade through the complex manoeuvre known as turning directly away and accelerating to max speed. Now that becomes a problem when you're talking about building an interceptor to shoot down hypersonics when the hypersonics themselves are already pushing the boundaries of what we can accomplish in terms of performance. And there's one other way in which having a manoeuvring projectile makes things very difficult for the defender. Whereas the final target of a ballistic missile can be calculated relatively quickly because it follows a predictable trajectory, the final target of something like an HGV is not going to be obvious until potentially far too late.

And that's one of the reasons that particularly nuclear-armed HGVs have been identified as a potential strategic risk. In that they might provide pressure on a potential target to make a terrible mistake, or to reward an aggressor for making a first nuclear strike. Here's a really simple diagram to illustrate the point. Imagine for a moment that both Emutopia and Kiwiland here are nuclear weapon states, but they both only have ground-based nuclear weapons. Emutopia also obtains a supply of hypersonic glide vehicles, and like North Korea before it, decides that a great use of its expensive new missile systems is to wage war against fish in the ocean. And so Emutopia begins firing hypersonic glide vehicles at targets to the north and south of Kiwiland.

These launches however, put Kiwiland in a very difficult position, because those HGVs could be intended to wage war against oceanic wildlife, but they also have the potential at the last moment to execute a turn and instead target Kiwiland centres of government, communication, and their nuclear weapons silos. Now if the Kiwis wait until it's obvious that they are going to hit those targets to try and launch, their weapons are going to be destroyed on the ground - they'll lose their ability to retaliate. But if they launch as soon as they detect the original firing of the HGVs, then the Kiwis may end up destroying their civilization in defence of sea life. This is one of the reason that things like dual-purpose (that is conventional or nuclear-armed) HGVs can be so dangerous.

When one goes up, unlike a ballistic missile, no one really knows what the final target is and no one knows if it's carrying a nuclear weapon or not. That ambiguity in some ways makes it a more effective weapon. Now there are reasons to not exaggerate the threat, but generally speaking, when the words "nuclear" and "miscalculation" are combined in the same sentence then sometimes people can get a little bit nervous. If it makes you feel any better, the United States has made it clear that it doesn't intend to develop nuclear-armed hypersonic glide vehicles. But Russia claims to have already fielded one, so sleep well. Alright, so those are the benefits in a nutshell.

Hypersonics may offer less warning time than a traditional ballistic missile. They may be able to hit a target much faster than a conventional cruise missile or an airstrike. They can probably evade any existing missile defence system. And for good measure their final targeting is often ambiguous.

All up, that seems like a pretty reasonable sales pitch, and you might be forgiven for wondering whether or not hypersonics make all other conventional weapon systems obsolete. After all, why would you want to go slow when you could go fast? The reality however is that there's a lot of technical costs and considerations that stand in the way of hypersonics becoming dominant. And they have a way of adding zeros to the resulting price tag. Perhaps the easiest way to conceptualise this is just imagine speed as having a cost. Now different aircraft are obviously designed to operate ideally and efficiently at different speeds. But all else being equal, flying fast - that is going supersonic, does bring on costs.

Because flying faster is going to generate more air resistance, you're going to expend more energy doing it. And you're going to need to reinforce your airframe and redesign it to survive the stresses of flying at higher speeds. That's going to drive up cost and limit things like payload. It's one of the reasons conventional commercial air travel is subsonic, not supersonic.

If you want to go really quickly through atmosphere, the physics gods demand tax. A great historical example here is to compare the American F-8 and A-7. The Vought F-8 Crusader was an American supersonic carrier-based fighter, and a pretty damn good one at that. It would later serve as the basis for a distinct but very closely related aircraft, the A-7 Corsair II.

This wasn't a supersonic fighter, it was a ground-attack aircraft. And in redesigning it the designers managed to find a way to increase its range, reduce its takeoff weight, and multiply its ability to carry ordnance several times over. And one of the main ways they did that was simply by making the aircraft subsonic. By simply removing all of the concessions that existed to allow this thing to fly at supersonic speeds, you were able to get a cheaper airframe that was capable of doing far more heavy lifting. We already know that this holds true for missile design as well.

Generally speaking, the Russians build pretty good missiles and rockets. The Onyx anti-ship missile, which you can see there on the bottom, is a pretty impressive piece of kit. But compared to the Tomahawk very roughly, it's got a smaller warhead, weighs about twice as much, and has perhaps half the range. And depending on how you measure it, it may also be significantly more costly. The primary driver here isn't that the Russian designers are incompetent, or that Tomahawk is a particularly modern cruise missile. They are not, and it's not. The problem is that Onyx is a ramjet powered design that has to travel at more than twice the speed of sound.

You can probably see where this is going as we try and ramp the Mach numbers up above 5. A more specific issue is that going very quickly within the atmosphere is going to cause things to get very hot, very quickly. Temperature can become a serious concern, particularly at what are called stagnation points. And the increase in heat isn't linear with an increase in airspeed. All else being equal, doubling your velocity doesn't just double your temperature.

And so you see reports for example, of the American X-51 test vehicle travelling at Mach 5, so relatively slow for a hypersonic weapon, you're already talking about four digit temperatures in Celsius terms at certain points on the aircraft. And for all users of Freedom Units out there, by the time you hit 1,000 Celsius you're already at 1,800 Fahrenheit. At very high temperatures, when you start talking thousands of degrees Celsius, things can get difficult from an engineering perspective. Even if materials don't melt, they may warp or weaken. A steel beam doesn't have to melt in order for something to catastrophically fail. If it's bearing load and it gets soft, you're going to have a significant issue.

Another problem you might have at very high speeds with certain designs is called plasma sheathing. Essentially this is when the shock heating caused by a hypersonic vehicle moving through the air is so violent that the air creates a sort of cocoon of plasma around the object. The problem there is that it can impede communications and sensors. In a sense, a hypersonic wrapped in plasma would essentially be deaf, dumb and blind. Unable to see with its radar or communicate with its control station without slowing down and dispersing the plasma.

And if a hypersonic has to slow down a bunch, well, it's not really doing a good job of being a hypersonic any more. Now contrary to some of the articles and videos I've seen on this topic, plasma sheathing doesn't seem to be an impossible to solve problem at all. Chinese researchers claim to have made advances in communicating with vehicles moving at very high hypersonic speeds.

And the US DOD is on record saying that they believe they can design their first generation of HGVs without plasma sheathing issues. But it's another challenge that imposes limitations on design and that has to be worked around. And by this point you're probably not surprised to hear that you're not going to build a high performance hypersonic weapon out of ordinary materials. I mean you could try and build one out of conventional materials like titanium and steel, but you're not going to have a hypersonic glide vehicle by the time it reaches the target area. We already saw this illustrated during the Cold War when Lockheed Martin came out with their famous SR-71 Blackbird reconnaissance aircraft. Now that plane could sustain Mach 3.2.

The plane overwhelmingly had to be built out of titanium. And ironically enough, because of shortages of the stuff in the States, a lot of effort had to be made to procure the necessary ore from the Soviet Union. The more exotic materials you need, the higher the cost is going to be. And if you try and cut corners on materials or tolerances, then physics are going to murder you without mercy or a second thought. Hypersonic vehicles are subjected to incredible pressures and stresses, and so tolerances are going to be tight and reliability might suffer.

Drive a car with a couple of dents or scratches, or miss a necessary service window, you're probably going to be OK. Try and fly at hypersonic speeds with anything on that vehicle out of whack, you're probably just going to die. And if you do hit your target, the effect on that target might not be what you're imagining.

Because all else being equal, there's going to be less room on a hypersonic weapon for a warhead than a conventional option. Now one way to get away with that instead is to look at the energy of the projectile itself, how much kinetic energy do you get from slamming the projectile into the target? Convert that figure into TNT equivalent, and you can argue that a hypersonic weapon is considerably more damaging than most conventional options. I mean I've lifted a statement directly from the Wikipedia page on the Kinzhal there basically arguing that at two tons and Mach 12 it has the equivalent of four tons worth of TNT in kinetic energy. Leaving aside the fact for the moment that most hypersonic weapons are not going to hit that target at anywhere like their maximum speed, comparing kinetic energy directly to warhead yield is a little bit dodgy. Because how that energy is transmitted ultimately matters. Against some target types simply smashing the missile into the target at high velocity might have a great effect, things like against buried bunkers or against ships.

But against other targets, well there's a reason that a lot of weapons use for example, air-burst warheads where they detonate above the target. There might be cases where a 500 kilogram warhead with high explosive and pre-formed fragments, or cluster munitions, might have a much greater effect on the target than slamming something heavy into the dirt at Mach 10. If you want an imperfect analogy, remember that a punch delivered by a professional boxer might have the equivalent kinetic energy to a small pistol round. But they're going to have very different effects on your chance of survival if they're both directed at, say for example, your heart area.

Now none of these costs are impossible to compensate for. You can make a vehicle with enough energy to go really, really quickly, made of the right materials to endure really, really high temperatures manufactured to incredibly high tolerances so it's reliable despite its incredibly high performance. And then make it big enough to carry a reasonable warhead to have a large effect on target despite all the other concessions that have been made. And at the end of the day the cost of all those costs being compensated for is just cost, it's just cold hard cash. And so you start talking about HGV systems that cost tens of millions of dollars per shot. And you may end up with a weapon system that is very capable, and which can engage a wide range of targets on a very short time frame, but with all the economic efficiency of rigging an F-16 for unmanned flight and then smashing those into your chosen target.

A hypersonic may be a potential answer to a given military problem, but because of their cost and complexity they may not always be the right weapon for the job. Which is why I want to look at the missions that hypersonic weapons are hypothetically meant to fill. Because ideally weapon systems shouldn't exist just for prestige purposes. You're looking at a class of weapon here that because of the underlying physical requirements is probably always going to be significantly more expensive than other systems. And so if you're purchasing them in numbers, it had better be for a good reason.

And if you're smacking 40 million dollar missiles into a target that could have been dealt with using a $20,000 guided bomb, then someone's going to have to explain to Joe Taxpayer that his district doesn't get a new school because someone thought it was a bright idea to slam a hypersonic into two insurgents in a Toyota. This is why US thinking, insofar as we can piece it together from comments by various officials so far, is that hypersonics shouldn't be used against any old target. Instead they should only be used against targets that are both extremely valuable and extremely time sensitive. With the added benefit of holding a whole range of targets at risk, we'll talk about that one later. In the absence of those conditions, if you are talking about the conventional mission, you need to talk about competitors, other weapon systems that might do the job instead.

So let's do exactly that, looking at the two different missions of hypersonic weapons, the nuclear role and the conventional one. The nuclear mission is at the core of Russian thinking on hypersonics, and may be a feature of the PRC's programs as well. The stated idea here is that things like hypersonic glide vehicles like the Russian Avangard can be used to evade missile defence systems and to ensure that nuclear weapons hit their targets. In some ways this is strange, because according to the Russian government existing US missile defences pose no threat to Russia's ICBM arsenal, and won't for the upcoming decades. In relation to Russia's new ICBM the Sarmat for example, the commander of Russia's Strategic Rocket Forces, General Sergei Karakayev, is reported to have said the following, "Today they say that air defence does not exist for the Sarmat missile system, and it probably will not exist in the coming decades." And so I ask a question which will be repeated later when we talk about the Russian hypersonics program, is why spend billions of dollars on a nuclear weapon system designed to penetrate a missile shield that can't stop your existing weapons, is unlikely to stop them any time in the foreseeable future, and which doesn't threaten your existing second-strike capabilities? In that sense nuclear HGVs seem like a solution looking for a problem.

Because I don't mean to scare anyone listening to this, but the reality of ballistic missile defence currently is this: missile defence is really, really hard and really, really expensive. And there is no country on the planet, including the United States, that currently possesses enough missile defence to protect all of its people from an all-out nuclear attack by a major nuclear-armed country. Missile defence is instead aimed at smaller attacks by less capable opponents, targets like North Korea. And if a country is ever concerned about a missile shield becoming a problem, then there's always the option to overwhelm the available interceptors. Remember interceptors need to be very high performance. The way they do this is something we came up with during the Cold War, the idea of the Multiple Independent Re-entry Vehicle.

This is a system whereby one ICBM doesn't carry one warhead, it gets into space and then releases half a dozen, or a dozen. Or a dozen plus additional dummy warheads that act as penetration aids. Now unless you can intercept that missile before it releases its MIRVs, you need at least one interceptor for every re-entry vehicle. And even if you can absorb the stratospheric cost of building that massive fleet of interceptors that are somehow capable of covering every potential city target within your nation, it still might not be enough, because the maths gets brutal really quickly. If you have a 99% chance of intercepting any given incoming MIRV, then if your opponent fires 30 missiles and releases 300 independent re-entry vehicles, your odds of shooting down every single one is less than 5%.

And given that a single failure might mean something like Beijing or Los Angeles disappearing, that's still a pretty strong deterrent. So while I'm sure that things like hypersonic glide vehicles are perfectly capable of accomplishing the nuclear strike mission, it's kind of like asking whether we could use surface-to-surface rockets for Amazon Prime deliveries. The answer is like probably, but a truck works just fine. In the ground strike role there are certain targets that you can rule out almost immediately.

Namely, any target that isn't valuable enough to be addressed by a hypersonic system probably shouldn't be. Superpower militaries are by definition fairly well funded, but if they start slamming hypersonic cruise missiles into T-55s even they are going to run out of bang pretty quickly. So we are left pointing hypersonics at targets that are valuable enough to merit being targeted, that need to be addressed right now, and that benefit from something that can penetrate missile defences. On land that might include high priority targets like high-level headquarters or particularly important high-powered radar systems. And at sea the obvious target is going to be something like an aircraft carrier, or a cruiser, or a principal surface combatant of some sort. Surface ships tend to be heavily defended, they're very expensive, and they have the capacity to do a lot of damage if employed correctly.

But the requirement that the target needs to be hit right now probably still matters. Because if a target is valuable but not urgent, and you're looking to replicate some of the hypersonics other features like low warning time, there are other options that already exist. For example, one way to reduce warning time instead of flying really fast is instead to fly really, really, really low. A lot of modern anti-ship missiles fly only just above wave top level. And because they can camouflage themselves against the water and exploit the Earth's curvature, often the warning of these sort of systems even if they're travelling quite slowly is going to come very late. There might be less than a minute of warning between a sea skimmer being detected and it impacting its target.

Sea skimmers reportedly sunk the Moskva, sea skimmers were used by the Argentinians during the Falklands War. And you can make a weapon relatively cheap and light that can still fly low and get low warning times as a result. Another option that's again already in use, is to reduce warning times not by making the weapon go faster, but by making the weapon harder to see. If you look at something like the extended-range version of the American AGM-158 for example, that thing's got a range out past 900 kilometres.

Compared to hypersonics it's going to be considerably cheaper. The current cited numbers are about 1.5 million dollars per unit at an annual production rate of north of 500, moving towards potentially 1,000. And while it is subsonic, it has a stealthy design and a significant warhead. And unlike hypersonics you don't need a specialised deployment platform, no rocket booster, no aircraft to carry it to altitude first. You can literally dump these things out the back of a cargo plane by the dozen.

Or if you want to reach targets even further away while keeping warning times low, or if you want the ability to use cheaper weapon systems against hard to reach targets, well how about instead of making the weapon difficult to see, you make the launching platform difficult to see. Aircraft like the B-2 Spirit, the B-21 Raider and the F-35 already exist. Their low observable features don't make them invisible to enemy air defences, but it does reduce the range at which they can be detected, acquired and engaged.

So instead of building a really expensive weapon system that I'm going to smack into a target, instead I can build a very expensive plane that lets me get a cheap weapon, say an extended range JDAM or a JSOW closer to a target, drop the cheaper weapon with an equivalent warning time, and then the good thing is I get to use the plane all over again. Now this option and the others I've cited do all fail on the same criterion: timeliness. If you need to hit a target right this second, you probably don't have enough time to get a B-2 into theatre.

But in the absence of that time pressure, this is an existing, far cheaper, potential solution. Both to the issue of penetrating air defences and also to reducing warning times. Finally, instead of trying to use something like a hypersonic to just shoot through enemy air defences, you could instead aim to exhaust or saturate enemy air defences. In this scenario instead of sending one or two horrifically expensive weapons, you're probably going to employ dozens, hundreds, or even thousands of much cheaper systems.

This operates on the logic that any air defence system only has so many launchers and so many interceptors, both in general and protecting any given target. If I fire 40 Tomahawks at a target and they only have 30 interceptors available, the target is going to be destroyed. And we see the Russians employing these sort of tactics now in Ukraine, employing things like the Shahed 136 from Iran.

It would be grossly unfair to compare these lawnmower drones to hypersonic weapons. But they do offer Russia an option, an opportunity to stress and wear down Ukrainian air defences without bankrupting the Russian state. Now don't read too much into the positioning of any option on this table, but just for the consultants in the room I've thrown up a two by two. What I'm trying to illustrate is that in an ideal world, the target's value and time sensitivity will help inform the weapon that is used to engage it. Hypersonics are at their most useful in that extreme top right corner where a target is both extremely valuable and time sensitive. To use a really imperfect analogy here, something like an air-dropped JDAM is free, three to five business day delivery.

And an expensive cruise missile is next day express. And hypersonics are that novelty option where you pay like 500 bucks to have it delivered in 15 minutes by a drone or something. There might be rare ... circumstances where that's worth it. But most of the time you're probably better off waiting. But that still does leave hypersonics with a limited but dangerous role. And if they can be used to hold valuable targets, things like aircraft carriers or headquarters at risk, then there will still probably be a need to have defences against hypersonic weapons.

And so I want to move on to the defensive challenge and some of the responses out there. Now I've sometimes read about the hypersonic threat being dismissed as basically a case where the proverbial sword has got ahead of the shield. That argument essentially goes that whenever a weapon is invented people try and invent a counter-measure, and that while hypersonics are dangerous now that's only because defences haven't caught up yet. I do want to object to the inevitability of that statement by saying this: physics matters, and the shield is not always destined to catch up.

In areas like nuclear warfare for example, nukes are so devastating and attack is so much easier than defence, that even after decades of trying to solve the problem deterrence remains in place because all sides still remain at mutual threat. And even if you come up with a solution, there's no guarantee that it's going to be economically viable. But leaving that point aside, what do you need to do in order to defend against hypersonics? Well, you need to reverse the advantages they currently enjoy. Hypersonics have an advantage because it's hard to detect them until it's too late, and existing defence systems have a real rough time intercepting them. And so the two core problems are detection and interception.

Now I illustrated the really scary detection problem using this image before. The hypersonics come in low, the radar on the other side of the planet is limited by the curvature of the earth and only gets to see them at the last possible moment. Now there's two things to say about this particular scenario. The first is that it's pretty idealised, mainly because the target country has decided to put its radars only in the target country. But if you're a country like the United States with allies, or if you have mastered really advanced technology like boats, you have another option.

Because if you just add some sensors closer to the launch location, they're going to detect or potentially detect the launch profile of the cruise missile or the hypersonic glider. And provided you have those sensors networked with your wider defence system, that's going to give you early warning that the systems are at the very least in the air. Another option is instead of building sensors that are on the ground looking up, build sensors in space looking down. At that point, unless the missile is literally subterranean, it's going to be within line of sight of a space-based sensor. And while it may sound sci-fi, this is basically the solution that it looks like the Americans have settled on.

There are two main American satellite systems at play here. Firstly you're going to have satellites of a system like the Space-Based Infrared System with infrared sensors in a high orbit capable of covering a wide area. What those satellites are there to do is to detect the tell-tale signs of a weapon being launched. Remember, something like an HDV is usually going to be launched by a ballistic missile. So there's going to be a plume, there's going to be heat, there is going to be something there to detect. After all, detecting ballistic missile launches is again something we could already do during the Cold War.

But those satellites aren't precise enough or low latency enough to give you information detailed enough to inform a targeting solution. So the plan is to then have a large constellation of satellites in a much lower orbit making up the Hypersonic and Ballistic Tracking Space Sensor system. Now that's very impressive from a technical perspective but a complete failure of an acronym, so we are going to give the program overall a 1 out of 2. The program is in the prototyping and testing phase as of 2023. And is intended to generate high quality tracks capable of facilitating an intercept. And while the idea of tracking fast-moving objects from space sounds difficult, and it is nightmarishly difficult, there's one sense here in which hypersonic missiles are actually a far easier opponent than something like a conventional cruise missile.

One of the big challenges of space-based sensors is discriminating between targets and clutter. If you program a system to look for a small metal object, you'll rapidly discover that there are an awful lot of small metal objects on planet Earth. But a hypersonic missile isn't just a small metal object. It's a fireball that may be burning at several thousand degrees and moving at 5 to 20 times the speed of sound. So there are some unique characteristics for a system to home in on.

So while the solution isn't proven as of yet, the concept at the very least is in place. And if it all comes together, then the detection side of the problem at least will have been solved. Then comes the problem of shooting the projectile down, either in its terminal phase, so right before it hits its target, or during the glide phase in the case of a hypersonic glide vehicle. For terminal defence there might be solutions in place if existing systems can be adapted to the challenge. They may not be a perfect solution and may only be able to defend a relatively small area, but the US Missile Defence Agency is already planning to upgrade the existing Aegis defence system. Combining Aegis cruisers and the SM-6 missile into what they call the Sea Based Terminal system.

If fielded, this would be yet another example of most of the US surface fleet completing one of its primary objectives: keeping the aircraft carriers alive. Meanwhile Russia claims that no upgrades are required because the S-500 can already engage things like hypersonic cruise missiles at very high altitudes. The source on that however is Russian state media, so some healthy scepticism may be in order.

But as some American officials have put it, and as logic would suggest, you don't want to be intercepting in the terminal phase unless you really have to. Ideally you want to engage further out and protect more than just the local aircraft carrier. This is where you find programs like Raytheon's Glide Phase Interceptor.

This is the plan to pair a very high-performance interceptor with those satellite-based sensors that we talked about earlier in order to intercept hypersonic gliders while they're still in that glide phase. Now that's obviously an intense technical challenge. But even the existence of such a system might place a tax on how hypersonic gliders are used. For one they may have to manoeuvre more in case there is an interception attempt, but every manoeuvre by a hypersonic glider reduces its range.

We're talking about systems where making a 30 degree turn might take 4,000 kilometres and sacrifice kilometres of altitude. So even just forcing these gliders to fly a more evasive path has its own military value. In that respect it's kind of like planting even just a few mines in the path of an enemy advance. It's certainly not going to stop a determined opponent, but if Private Conscriptovic is poking at the ground with his bayonet every metre or so checking for mines, the offensive is going to be less powerful and much slower than it otherwise would be. A final note here is that there's room potentially to get creative in the area of interception. The Missile Defence Agency in 2017 reportedly commissioned 21 different white papers into different interceptor options.

Everything from missiles to lasers, to electronic and microwave attack, to hypersonic projectiles fired from rail guns. Remember we talked about Japan the other week. Whether any of these become viable alternatives to trying to hit a missile with another missile at 5 times the speed of sound remains to be seen.

But given the danger, you can expect countries to continue their best efforts. So if that's hypersonics in general, the threat they pose and potential counter-measures, it's now time to look at individual nations and their programs. And there is no better place to start than the nation that has talked about its hypersonic capabilities perhaps more than any other, the Russian Federation.

Now I have seen people prone to mocking Soviet and Russian technology. My view on that has always been do so at your own peril. There have long been specific fields in which the Soviet Union, and thus by continuation the Russian Federation, have performed very well in a technical sense. The Soviet Union was quite capable of designing and building impressive rocket systems and impressive airframes. It fell down a little on things like miniaturised electronic to put in those airframes, but the underlying performance characteristics of something like a Flanker are pretty impressive. And the Russian hypersonics program build on that expertise, particularly in the field of rocketry.

In 2019 Putin declared to the world that Russia was leading the world when it came to hypersonic weapons. And in terms of mission, Russia has looked to hypersonics to fill 3 main roles as far as I can assess. A nuclear mission aimed at penetrating US missile defences, some sort of anti-shipping or anti-critical target conventional capability, and of course prestige.

And to achieve those goals there are three key systems that they're talking about. The first system is the one with which I began this presentation, the missile that Russia has actually fired in the war in Ukraine. This is the Kinzhal. NATO reporting name AS-24 Killjoy, so-called because it kills the joy of everyone in the room whenever the debate begins over whether or not it should be included in the list of modern hypersonic weapons.

Make no mistake, Kinzhal does travel at hypersonic velocities. But it is neither a hypersonic cruise missile or a hypersonic glide vehicle. Instead it's actually a ballistic missile. Because what it appears the Russians have essentially done is modified their ground-launched Iskander ballistic missile, and instead of firing it from the ground now they launch it from an aircraft.

The Russians stress that it's moving too fast for Ukrainian air defences to intercept, which is true. But that's also true for the ordinary Iskanders when fired from ground launchers. Now I don't have time to spend too long ripping on the Killjoy.

I'm not going to dwell for instance on the fact that it probably contains Western-made components. Instead I'm going to focus on its stated performance characteristics, including the shocking number of publications that list the range of this missile as between 2,000 and 3,000 kilometres. Now those are the ranges claimed by Russian state media. But the reason those ranges differ so much is because it depends on the carrying aircraft.

Carried by a MiG-31 the stated range is 2,000 kilometres. Carried by a Tu-22M the range increases to 3,000. Why? Because the Russians include the combat radius of the launching aircraft in the range of the missile, but that isn't how ranges are normally expressed. By that logic the 30mm cannon on the A-10 has a range of hundreds of kilometres, because you can fly the plane hundreds of kilometres and then fire the gun.

It's ultimately harmless as long as you know that this is how the range is being reported. But at the same time, I'm now trying to figure out if I can set a javelin world record by throwing one out the side of a moving plane. I'd love to see even a professional athlete match a throw measured in kilometres. Nor does the Killjoy represent some sort of new, unique, dangerous technology. For example, here's the GAM-87 Skybolt missile from 1962. It was also an air launched ballistic missile, about 1 ton heavier than the Killjoy at 5 tons.

But with a standalone range of 1,600 kilometres and a maximum speed of something like Mach 12. So yeah, this is just your daily reminder that designers in the '50s and '60s had exactly zero chill. Now having been built in the 1960s it obviously wasn't precise as the Killjoy, but the technical capability was there and yet the missile was cancelled anyway. One of the reasons being no one really saw the point.

Ordinary ballistic missiles, particularly submarine launched if you're talking about the nuclear mission, simply did the job better. And with Skybolt's limitations and difficult development history, it went the way of the dodo. Another notable issue with the Killjoy is that it doesn't actually have one of the primary advantages you associate with hypersonic weapons, that is low warning time. The issue here is that at the moment Killjoy is primarily launched from a small number of specially adapted MiG-31s. And so you can probably already see the problem. Every time those specially adapted MiG-31s are detected taking off, Ukraine triggers an air-raid warning.

Because the warning time is not just equal to the flight time of the missile, it's equal to the time the aircraft takes to get to altitude, launch the missile, and then the flight time of the missile. This is compared to just launching Iskander from the ground and providing basically zero warning. None of this is to say that the Killjoy has no military utility. It has missions it can do, and it's clearly hard to intercept. But it's an expensive specialised system, of which the Russians probably had a pretty small inventory, that requires a specially-adapted launching platform. All to do a mission that in a lot of cases could have simply been done by some other system instead.

Avangard is the next system, and this is Russia's hypersonic glide vehicle. Almost all of the open source information here comes from Russian state media, so keep that in mind. But as Russia expresses it, this is an operational weapon system that is usually deployed by the SS-19 ballistic missile, and which is capable of travelling at speeds of Mach 20 to 27 and delivering a nuclear warhead. Notably among all the claims that Russia has made, including that very high top speed, the idea that it is highly manoeuvrable, that it's invulnerable to ballistic missile defences, and that not only can it do Mach 27, it can do it in the dense layers of the atmosphere, so low down, I haven't seen any particularly impressive claims when it comes to accuracy. Now that may be fine for a nuclear delivery system, but not so much for conventional strike. So what we are probably looking at here is a dedicated nuclear strike system.

The final system of note is the 3M22 Zircon. This is Russia's hypersonic cruise missile, and probably the most important of the three. Russia claims that this is a relatively small missile, 8 to 10 metres long, suitable for maritime use in the vertical launch systems of things like the Yasen-class submarines.

It has a reported top speed of between Mach 6 and Mach 8 with a 300 kilogram warhead. And the advertisement here is that this is a potential anti-ship missile system. Now if all of those claimed characteristics are true at the same time, then this is a terrifying new capability for the Russian Navy. At the same time I think there are some reasons to ask questions. For one, the development cycle was relatively short for a missile like this one, and there were no reported testing failures.

There are claims that some of the footage

2023-05-04 19:17

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