Countermeasures for hypersonic weapons

[FactChecker]

Oh my God.
I honestly thought Russ was talking about the mass of the jet.

Then you are right -- that IS a hell of a jet! :-)

 

[berkeman]

Yeah, another example of Imperial tonnes versus sailing/aero knots. Lordy.

 

[Rive]

It seems that conventional interceptor missiles would have to be hypersonic themselves, and even more nimble, to be able to intercept incoming hypersonic missiles.

Yes. No.
Yes, they have to be fast. But that 'fast' is about doing the job 'farther the better' and not really about the speed of the target.
Since the job is actually about laying a nice debris field in the right moment at the right place, the speed of the incoming missile is actually not that important (except, that higher speed will do a slightly better headbang on that debris field).

The following part about the sensors is more important.

there will undoubtedly be issues with mounting sensors for terminal guidance on interceptors.

That debris field must be at the right place, in the right moment. This requires a quite fast and accurate response. That's the real challenge.

 

[FactChecker]

Since the job is actually about laying a nice debris field in the right moment at the right place, the speed of the incoming missile is actually not that important ...
That debris field must be at the right place, in the right moment. This requires a quite fast and accurate response. That's the real challenge.

The required speed of the response is a function of the speed of the approaching target. A slow target allows a slow response and a fast target requires a fast response.

 

[Rive]

The required speed of the response...

Speed has a secondary meaning here as 'low response time' // 'low delay'.
For any intercepting device the 'fast' as 'high speed' is not necessarily better since the high(er) relative speed makes it harder to respond (to any direction change).

 

[FactChecker]

Speed has a secondary meaning here as 'low response time' // 'low delay'.
For any intercepting device the 'fast' as 'high speed' is not necessarily better since the high(er) relative speed makes it harder to respond (to any direction change).

The post I commented on was referring to the speed of the incoming missile, not the defense system. The speed of the incoming missile has a very direct influence on the required reaction speed of the defense.

 

[boneh3ad]

Speed has a secondary meaning here as 'low response time' // 'low delay'.
For any intercepting device the 'fast' as 'high speed' is not necessarily better since the high(er) relative speed makes it harder to respond (to any direction change).

The responding countermeasure needs to be fast enough to adequately respond to any lateral/vertical maneuvering of the attacking vehicle, but it certainly doesn't need to be able to chase it down from behind (though perhaps that would make for an easier interception if you could actually pull it off). However, speed buys more time for additional intercept attempts in the event that the first one fails.

For what it's worth, though, existing terminal ABM systems (at least in the US) sort of fall all over the place in terms of Mach number, but are often themselves slower than the target. Essentially all of the current US, Russian, and Chinese terminal ABM systems fall in the Mach 3.5 to 4.5 range as far as publicly released data shows, with the exception of THAAD, which can hit Mach 8.2. They still all have a fairly low probability of success with a single missile against ballistic targets, which are faster but more predictable than the current batch of maneuvering hypersonic systems. That's why it's not uncommon to launch multiple interceptors at a single incoming threat.

It's generally easier to intercept before the RV re-enters the atmosphere, but that's not an option with the current batch of hypersonic missiles in development.

 

[Klystron]

Countermeasures and counter-countermeasure deployment in an integrated battle space depend on mission objectives of the attacking force versus resource conservation and allocation of the defenders.

Position; therefor, change of position over time, while important and impressive remain another input set. Attacker stealth to avoid detection including unexpected approaches such as nap-of-the Earth and extreme altitudes, radial closure toward emitters, coordinated attacks combining tactics, coupled with anti-radar and other CCM; contribute to successful missions surpassing incoming velocity.

Relying on extremely high incoming velocity for penetration of an area risks creating a virtual "Maginot Line" in space. Game changing innovations and ultimate weapons rarely survive first contact. Defenders learn to adapt.

 

[boneh3ad]

Relying on extremely high incoming velocity for penetration of an area risks creating a virtual "Maginot Line" in space. Game changing innovations and ultimate weapons rarely survive first contact. Defenders learn to adapt.

But that's just it; this is effectively the case with existing ICBM tech. That hasn't changed a whole lot in recent years and most countries invested in ABM systems have decided that interception in space is the highest-probability approach. If that fails, the RVs re-enter and have very limited maneuverability so there's a shot at hitting them with a terminal defense system like THAAD, Patriot, or Aegis. In effect, that Maginot line in space is what we have now.

The new breed of hypersonic missiles avoid those problems by simply not flying into space and remaining maneuverable up until the very end of the flight (a link back to the previous CRS report I cited). The figure from the CRS report pasted below is a good, simplified visual.

Figure 1 from the CRS report

Over time, I am confident all parties will concoct appropriate defensive measures, but substantial challenges remain. The original poster, @neanderthalphysics, correctly pointed out some of the major challenges associated with various methods that have been considered to defeat these weapons and was flamed out of his own thread for it for not already being an expert on the solutions (which, again, no one is).

 

[shjacks45]

But that's just it; this is effectively the case with existing ICBM tech. That hasn't changed a whole lot in recent years and most countries invested in ABM systems have decided that interception in space is the highest-probability approach. If that fails, the RVs re-enter and have very limited maneuverability so there's a shot at hitting them with a terminal defense system like THAAD, Patriot, or Aegis. In effect, that Maginot line in space is what we have now.

The new breed of hypersonic missiles avoid those problems by simply not flying into space and remaining maneuverable up until the very end of the flight (a link back to the previous CRS report I cited). The figure from the CRS report pasted below is a good, simplified visual.

View attachment 275339
Figure 1 from the CRS report

Over time, I am confident all parties will concoct appropriate defensive measures, but substantial challenges remain. The original poster, @neanderthalphysics, correctly pointed out some of the major challenges associated with various methods that have been considered to defeat these weapons and was flamed out of his own thread for it for not already being an expert on the solutions (which, again, no one is).

I am a bit confused. The hypersonic tests that I've heard of fly these hypersonic devices in higher altitude thinner air. So with this hypermaneuverability hypersonic missiles will travel 50 feet above the ground like cruise missiles? Since the hypersonics are tested at high altitude, do we know what happens to a mach 6 hypersonic device hitting a rain squall? And active radar targeting that is unjammable?

It is wrong to judge the maneuverability of a missile the same as an airplane. A modern fighter airplane can get much greater aerodynamic forces than thrust forces and turn at up to 9 Gs from its aerodynamics. It could never get 9 Gs of acceleration from thrust. Some missiles can get much greater thrust/weight from their propulsion and can achieve up to 20 G maneuvers. They just need to turn their thrust in the right direction. They don't need to rely on wing-loading and aerodynamics.

I'm in space and turn my thruster, firing the thruster (offset from its center of gravity) makes me tumble in space. Same with the missile with low drag fuselage, except tumbling would be suboptimal for continued mach 5.5 flight, likely including structural degradation. A few videos of supersonic aircraft disintegrating in flight after maneuvers. Maneuvering jets at front of craft could be used instead of larger drag inducing wing surfaces. But there is always new tech around the corner. Who would have thought 200mph cavitating torpedoes were possible, a few years ago.

 

[boneh3ad]

I am a bit confused. The hypersonic tests that I've heard of fly these hypersonic devices in higher altitude thinner air. So with this hypermaneuverability hypersonic missiles will travel 50 feet above the ground like cruise missiles?

It doesn't need to be sea-skimming at 50 feet to not be in space like an ICBM RV. One of these hypersonic missiles will be picked up on radar before something that flies extremely low like a Tomahawk would for sure. But a hypersonic system is moving so quickly that there is considerably less time to acquire, track and engage the target than with existing systems. They are also simply harder to hit because they are moving so quickly.

Since the hypersonics are tested at high altitude, do we know what happens to a mach 6 hypersonic device hitting a rain squall?

We know a bit, but this is still an active area or research both at the basic and applied level. There are some really cool experiments out there using ballistic ranges, too.

And active radar targeting that is unjammable?

I don't think anything exists that is absolutely unjammable, whether hypersonic or not. I admittedly am not a radar guy, though.

I'm in space and turn my thruster, firing the thruster (offset from its center of gravity) makes me tumble in space. Same with the missile with low drag fuselage, except tumbling would be suboptimal for continued mach 5.5 flight, likely including structural degradation. A few videos of supersonic aircraft disintegrating in flight after maneuvers. Maneuvering jets at front of craft could be used instead of larger drag inducing wing surfaces.

Planes are not missiles and are designed entirely differently. A missile essentially just needs to point itself in the right direction and then close distance as quickly as it can and doesn't need to worry about the physiological limitations of a pilot.

But there is always new tech around the corner. Who would have thought 200mph cavitating torpedoes were possible, a few years ago.

Plenty of people considering that the Soviet VA-111 Shkval torpedo was introduced in 1977.

 

[FactChecker]

I'm in space and turn my thruster, firing the thruster (offset from its center of gravity) makes me tumble in space.

I'm in space and turn my thruster slightly to rotate the missile toward the desired orientation. When the desired orientation is nearly obtained, I turn my thruster slightly in the opposite direction to slow the rotation. As the rotation is stopped at the desired orientation, I have centered the thruster. Admittedly, there are a lot of additional complications that need to be addressed, but all control systems are fundamentally like that.

 

[berkeman]

Plenty of people considering that the Soviet VA-111 Shkval torpedo was introduced in 1977.

Interesting! I was wondering how in the world you would guide something that was in a cavitation bubble, but Wikipedia says that the initial versions used inertial guidance only. They do go on to say that later versions included terminal guidance, but I'm still wondering how you do that. Would they need some sort of an extension out in front of the bubble to try to use sonar?

https://en.wikipedia.org/wiki/VA-111_Shkval

 

[boneh3ad]

Interesting! I was wondering how in the world you would guide something that was in a cavitation bubble, but Wikipedia says that the initial versions used inertial guidance only. They do go on to say that later versions included terminal guidance, but I'm still wondering how you do that. Would they need some sort of an extension out in front of the bubble to try to use sonar?

https://en.wikipedia.org/wiki/VA-111_Shkval

View attachment 275421

I don't actually know. I think it's a pretty un-maneuverable weapon in general, though, and relies on speed and surprise to sink a target before it can dodge. It would definitely be nontrivial to steer it, though. Fins operating in a bubble of water vapor would be pretty much useless, and fits that are longer such that they extend out of the bubble will increase drag dramatically and have to endure substantial forces. The Wikipedia article states that the fits would steer the torpedo by just touching the edge of the bubble and using that massive drag to create a moment that turns the vehicle. That seems reasonable.

EDIT: Actually, if you look at the tip of the Shkval more closely (large image attached below) that might be related as well. It looks like it tilts somewhat, so maybe they can shape the bubble in some way to aid with steering.

 

[BigDon]

FactChecker, you mention 9 g's in one of the above posts.

I spent much of my youth working on the avionics and fire control systems of F-14 Tomcats, in an elite outfit. A 25 ton bird that can do Mach 2.2 near sea level and burn their own paint off. ( Interception of a cruise missile from an unexpected direction in most cases.)

During a set of wargames vs the Airforce one of our pilots pulled and managed to stay conscious through a 12 g turn.

It freaking "bent" the airplane!

When he landed the wingtips were drooping three feet off the ground, instead of their customary 9 or so feet. Whizzing fuel all over hell and gone too. The central structural solid titanium I-beam that holds both wings together had to be replaced. It was bow shaped. A solid titanium I-beam, under bright hanger lights, is oddly beautiful, I must add.

Though the funniest example of how well Tomcats were engineered goes like this:

A lot of the places training and exercises take place are over the desert areas of Nevada and Arizona. Sometimes junior aircrews, and very much during training for low level tactics get lost and end up in Mexico, a very major faux pax as you can well imagine. And most aircrews would rather find their own way back than radio in their condition.

Most common way to find your way back? Stay low, find a highway, follow it head north.

Easy peasy, right?

So when we saw this one particular Tomcat land, after a brief thanks that it wasn't one of ours, we *knew* there was going to be a great story here.

I later learned it started with the Tower.

"Um, flight (whatever) is there something you'd like to tell us?"
"No, no, everything's fine. Had a great exercise!"

Without knowing, of course, that they had a full set of cross trees and two transformers from a telephone pole embedded in their port side horizontal stabilizer!

They never even knew they hit it! That's how tough those birds were.

(According to the serial numbers on the equipment the aircrew clipped off the transformers 20 miles south of the border.)

This was in fact what is referred to in military circles as a "Career limiting maneuver".

 

[berkeman]

During a set of wargames vs the Airforce one of our pilots pulled and managed to stay conscious through a 12 g turn.

With all due respect, I call BS. If this were true, it would be classified.

 

[Vanadium 50]

What's the difference between a fairy tale and a sea story? One starts out "Once upon a time, in a land far away" and the other starts out "No kidding, this really happened".

 

[Frabjous]

Wikipedia has an interesting article.
https://en.wikipedia.org/wiki/G-force

 

[Klystron]

Even so, @BigDon tells an interesting tale. Twin engine fighter planes going back to the near-transonic in a dive Lockheed P-38 Lightning can be difficult to target and track with anti-aircraft. Eccentric thrust and down low flying can leave fire control operators aiming where the aircraft was as opposed to will be.

USAF crews on the EW ranges always welcomed our Navy brethren in F-14 Tomcat, A-6 Intruder and EA-6B Prowler variants with relish and celebratory fireworks. I am certain the many near-misses by falling cement bomb, ECCM pod, chaff bundle, expended flare and detached aux fuel tank were kindly meant.

Grumman A-6 Intruder and the difficult to track Northrop Grumman EA-6B.

 

[DaveC426913]

What's the difference between a fairy tale and a sea story? One starts out "Once upon a time, in a land far away" and the other starts out "No kidding, this really happened".

"Even if you say it yourself, you wouldn't believe,
And I wouldn't trust a person like me, if I were you
I wasn't there, I swear I have an alibi
I heard it from a man who knows a fell who says it's true!"
- Johnny Tarr

 

[boneh3ad]

And here I got excited that this thread was revived only to find out we are talking about slow stuff.

 

[BigDon]

Sorry boneh3ad,

In deference to your disappointment I'll mention that there's one problem with the Soviet hypersonic missiles that didn't become apparent until recently in Syria.

Anybody want to guess what happens when you *miss* with a multi-ton, Mach 7 projectile?

It flies three horizons past the target until it finds something it does want to hit. Then your diplomats have to go on an apology tour of the various surrounding nations. (But so far that's only happened a mere five times...)

Klystron, guilty as charged.

By my count over the years my squadron alone has tried to hit you with at least two dummy sparrows and three drop tanks.

BUT we'd rather discover all those annoying short circuits in the emergency stores jettison system over your heads than our heads...

Simply economics. Good flightdeck sailors are much harder to come by than Air Force chair polishers.

(I am so joking.)

My favorite inter service rivalry joke that I've found to be semi-true. As in I've seen it.

Four of the main armed services are in a bar when a fight breaks out.

The Marines stand up and start hitting the Navy.
The Navy stand up and starts hitting the Marines.
The Army stands up and starts hitting each other.
And the Air Force stands up and hits the door...

 

[BigDon]

With all due respect, I call BS. If this were true, it would be classified.

(After reading through my post I have to state the following is written venom free.)

Yikes, your threshold is low. If that's all it takes I could start a thread called "Stuff Berkman Won't Believe" in the Lounge that would keep us both busy for years! Plus you have an odd idea of what should be classified information.

The basest note I've ever heard in my life was when I heard a five and a half acre sheet of three and a half inch thick steel get struck so hard a visible ripple was put in it. Like a stage play imitating thunder using sheet aluminum.

Ever encounter a king cobra? They're the largest venomous snakes in the world. They can rear one third of their body length without coiling. I've met one that was large enough to rear up and look me straight in the eye. This was something I thought I wanted to see.

I turned around and ran so hard I hurt my feet.

The only other time in my life I ran that hard, (where I hurt my feet so they were sore for days), was when I almost jumped on the back of a full grown male elephant seal. (Not intentionally of course.) Extra low tide at my favorite tide pool beach. Was jumping from boulder to boulder examining tide pools I don't get to access very often and I only hesitated because this one big rock was a different color than the basalt, browner, and I thought it might be "muddy" instead of rocky.

That hesitation saved my life. I was using my momentum to jump from boulder to boulder.

My shadow crossed over its head and all of a sudden this bull elephant seal with four massive lacerations on his face turns and roars at me from less than ten feet away. Then made a lunge.

I turned and didn't stop running until my feet were hitting asphalt.

I could go on...

 

[boneh3ad]

Sorry boneh3ad,

In deference to your disappointment I'll mention that there's one problem with the Soviet hypersonic missiles that didn't become apparent until recently in Syria.

Anybody want to guess what happens when you *miss* with a multi-ton, Mach 7 projectile?

It flies three horizons past the target until it finds something it does want to hit. Then your diplomats have to go on an apology tour of the various surrounding nations. (But so far that's only happened a mere five times...)

I am not sure what you are talking about here. Russia (note: not the Soviet Union) hasn't used hypersonic missiles in Syria. For one, they are not yet operational in all likelihood. More importantly, that would be an unbelievable waste of money given how limited the supply of their missiles are going to be for economic reasons. They wouldn't waste them on ISIL or else it degrades their ability to hold more peer-like adversaries at threat.

Are you thinking of the upgraded Kalibr missiles that Russia has used in Syria and Iraq? Those are subsonic and very comparable to US Tomahawk missiles and seem to have a history of crashing en route to the target.

 

[etudiant]

I find the hypersonic hype really strange.
A booster has only so much lifting capability, the weight of the hypersonic propulsion, guidance and/or aerodynamic control surfaces must be at the expense of the payload. What is gained by this?
Eisenhower noted long ago that he was concerned that eventually the country's leadership would have no military experience and consequently could not tell whether a new weapons program was useful or wasteful.
Hypersonics seem to me clearly in the latter category, sort of like the absurd 1000 mile range cannon the US Army is apparently considering.

 

[FactChecker]

FactChecker, you mention 9 g's in one of the above posts.

I spent much of my youth working on the avionics and fire control systems of F-14 Tomcats, in an elite outfit. A 25 ton bird that can do Mach 2.2 near sea level and burn their own paint off. ( Interception of a cruise missile from an unexpected direction in most cases.)

During a set of wargames vs the Airforce one of our pilots pulled and managed to stay conscious through a 12 g turn.

Interesting. G limits are programmed into the flight control of many modern fighters. I don't know anything about the F-14 and what type of flight controls were put into different variants.

 

[DaveC426913]

What don't you like about the obvious answers?

What is gained by this?

Compare a large payload, moving slowly enough to get shot down - to a smaller payload moving so fast that reaches its target without getting shot down.

Which one is better?

the absurd 1000 mile range cannon

Is it still absurd if it works?

If the Yangs have a 1000 mile cannon and the Comms have a 750 mile cannon, which side would you rather be on?

 

[FactChecker]

I find the hypersonic hype really strange.
A booster has only so much lifting capability, the weight of the hypersonic propulsion, guidance and/or aerodynamic control surfaces must be at the expense of the payload. What is gained by this?
Eisenhower noted long ago that he was concerned that eventually the country's leadership would have no military experience and consequently could not tell whether a new weapons program was useful or wasteful.
Hypersonics seem to me clearly in the latter category, sort of like the absurd 1000 mile range cannon the US Army is apparently considering.

A lot of smart people study the combat value of weapon systems. They take their job very seriously. I can imagine a lot of benefits from both hypersonic maneuverable weapons and 1000 mile range cannons.

 

[etudiant]

A couple of points:
The ballistic trajectory is very high speed, Mach 25 for an ICBM, much faster than the proposed hypersonics.
Moreover, one can send an ICBM on a depressed trajectory which reduces the warning time and the window for countermeasures, plus of course the warhead can be maneuvered.
Re the 1000 mile cannon, it is super dubious imho both technically as well as operationally. Check out the Navy debacle with the long range (only 60 mile) gun on the Zumwalts, halted because it cost close to $1MM per shot. Now make it go 10x further, at what cost and at the behest of whom? It suggests both economic as well as command and control issues.
Given the abundance of existing solutions, these efforts seem wasteful at best.

 

[FactChecker]

Check out the Navy debacle with the long range (only 60 mile) gun on the Zumwalts, halted because it cost close to $1MM per shot. Now make it go 10x further, at what cost and at the behest of whom? It suggests both economic as well as command and control issues.

The fact that some technologies fail is not proof that new technologies will not succeed. That has been true since the beginning of warfare.

 

[etudiant]

The fact that some technologies fail is not proof that new technologies will not succeed. That has been true since the beginning of warfare.

That is pure wishful thinking in this case.
There has been no substantial improvement in hypersonic propulsion efficiency, nor has the basic dishonesty of calling something a 'cannon' been addressed when the vast bulk of the range comes from a shell propulsion system that robs whatever payload the gun may have provided.

 

[FactChecker]

That is pure wishful thinking in this case.
There has been no substantial improvement in hypersonic propulsion efficiency, nor has the basic dishonesty of calling something a 'cannon' been addressed when the vast bulk of the range comes from a shell propulsion system that robs whatever payload the gun may have provided.

Maybe. I don't have the expertise or the security clearance to know anything about it.

 

[russ_watters]

Looks like we're about finished here, thanks everyone. Thread closed.
[edit]
I've received a request to give this one more try, so it's re-opened. Let's try to keep it on topic please. Thanks.

 

[boneh3ad]

I find the hypersonic hype really strange.
A booster has only so much lifting capability, the weight of the hypersonic propulsion, guidance and/or aerodynamic control surfaces must be at the expense of the payload. What is gained by this?
Eisenhower noted long ago that he was concerned that eventually the country's leadership would have no military experience and consequently could not tell whether a new weapons program was useful or wasteful.
Hypersonics seem to me clearly in the latter category, sort of like the absurd 1000 mile range cannon the US Army is apparently considering.

The ballistic trajectory is very high speed, Mach 25 for an ICBM, much faster than the proposed hypersonics.
Moreover, one can send an ICBM on a depressed trajectory which reduces the warning time and the window for countermeasures, plus of course the warhead can be maneuvered.

First, ICBMs are indeed faster than the hypersonic weapons currently in development, but it seems you are dramatically overestimating their maneuverability. They have some, sure, but they still follow a more or less ballistic trajectory. They aren't really easy to intercept, but they are easy to track and model, which makes the job somewhat easier. It's doable, if not a 100% success rate.

The bigger issue with the above as it relates to weapon systems currently in development is that you assume that forthcoming hypersonic weapons are using the same booster for the same mission as other weapon systems currently in the arsenal, specifically ICBMs, which is not accurate. At least here in the US, there are no plans to arm hypersonic weapons with nuclear warheads or to employ them in strategic roles. All of the systems currently in development and foreseen for the future are intended to serve a conventional tactical or theater role, performing long-range stand-off strikes in airspace that is denied to our current forces (e.g. by sophisticated air defenses or by shore-based anti-ship missiles that keep carriers out of striking distance).

Furhter, if they did come in nuclear variants, there would be no way to safely use the conventional variants for fear of an adversary mistaking it for a nuclear launch. There is then a likelihood that they would launch their own nuclear counterattack, and obviously no one wants that. The Pentagon has stated that their goal is to have thousands of these available for conventional use, so arming them with nukes would be counter-productive.

Re the 1000 mile cannon, it is super dubious imho both technically as well as operationally. Check out the Navy debacle with the long range (only 60 mile) gun on the Zumwalts, halted because it cost close to $1MM per shot. Now make it go 10x further, at what cost and at the behest of whom? It suggests both economic as well as command and control issues.
Given the abundance of existing solutions, these efforts seem wasteful at best.

I don't know a ton about the SLRC (1000 mile cannon), but based on what I have seen, there doesn't seem to be a lot of room for concern just yet. It's largely on hold for the moment while the National Academies Study it and create a feasibility report, so to me it sounds like they know it's a big risk and are getting outside opinions. Based on what's public, it seems that it would use some combination of traditional artillery shell explosive propulsion to get it going followed by a rocket booster. My major question is why would this need to be a gun instead of just using a missile, especially since the Army is working on fielding its own ground-based hypersonic missiles.

Either way, if you don't dream big, you don't make big technological leaps. The key is to dream big but pull the plug if it becomes obvious that the program is not feasible. DoD is not always the best at doing the latter part of that on time.

There has been no substantial improvement in hypersonic propulsion efficiency,...

This is not an accurate statement.

nor has the basic dishonesty of calling something a 'cannon' been addressed when the vast bulk of the range comes from a shell propulsion system that robs whatever payload the gun may have provided.

Do we know that the majority of its range comes from a shell propulsion system? I haven't seen that but that would definitely be eye-raising if true.

 

[Frabjous]

My major question is why would this need to be a gun instead of just using a missile, especially since the Army is working on fielding its own ground-based hypersonic missiles.

For some number n = (cost of missile)/(cost of projectile), the limitations of a gun launched system are outweighed by the number n of projectiles.