Countermeasures for hypersonic weapons

[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.

 

[boneh3ad]

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.

Sure, but clearly the shells for SLRC won't be "just shells." What sort of scaling up is required to hit that range and how does that adjust the denominator in your $n$? I don't know the answer to that.

 

[etudiant]

No argument that

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.
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.
This is not an accurate statement.
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.

The question of why not simply a missile is clearly central.
Afaik, even the rail gun efforts only deliver about Mach 6 at launch, deteriorating thereafter from air drag.
I'm unaware of any gun system that delivers a faster projectile and obviously sustaining that speed requires on board propulsion, plus guidance for targeting, because it becomes a non ballistic trajectory.

Separately, while there has been progress in hypersonic propulsion, the reported gains to date remain modest.
There has been no publicly reported long range self propelled US hypersonic flight since the last X-51 demonstration in 2013. The various projects such as the Lockheed AGM 183 are boost/glide vehicles, rocket propelled and then aerodynamically steered. That greatly cuts the available payload and adds costs.
The rationale for building hugely expensive small conventional strike systems remains questionable to me.

 

[Rive]

...when the vast bulk of the range comes from a shell propulsion system that robs whatever payload the gun may have provided.

At hypersonic speed a simple kinetic impact carries considerable damage potential.
On the other side, I'm not really sure that (chemical, still safe) explosives has enough time to detonate in such circumstances or you simply get the payload only splattered around the target upon impact.
Just think about the discarding sabot type ammunitions.

Ps.: of course, a payload may have it's own use: if you are considering missiles, then you need a pack of explosive to have a fragment field. But that's a different story.

 

[boneh3ad]

The question of why not simply a missile is clearly central.
Afaik, even the rail gun efforts only deliver about Mach 6 at launch, deteriorating thereafter from air drag.
I'm unaware of any gun system that delivers a faster projectile and obviously sustaining that speed requires on board propulsion, plus guidance for targeting, because it becomes a non ballistic trajectory.

No comment on the Mach number from a rail gun, but you are correct that a typical shell is several times slower. Presumably you could pack enough explosive behind it to get it going faster but at what cost? At some point the cost starts to approach that of a missile and the complexity is probably greater than a missile. If it's a ramjet-powered shell, as I've seen reported, then that solves some of the problems but introduces others. That's probably why they paused it pending the outcome of an independent feasibility study.

Separately, while there has been progress in hypersonic propulsion, the reported gains to date remain modest.
There has been no publicly reported long range self propelled US hypersonic flight since the last X-51 demonstration in 2013. The various projects such as the Lockheed AGM 183 are boost/glide vehicles, rocket propelled and then aerodynamically steered. That greatly cuts the available payload and adds costs.
The rationale for building hugely expensive small conventional strike systems remains questionable to me.

To the best of my knowledge, there hasn't been a flight test since X-51, though several are imminent. However, the advances in things like materials, flameholding/combustion, and ground test in the past decade have been pretty significant. Air-breathing weapons are absolutely expected to be the more challenging variety to develop (compared to boost-glide), but it's not insurmountable (or at least doesn't seem to be).

On the other side, I'm not really sure that (chemical, still safe) explosives has enough time to detonate in such circumstances or you simply get the payload only splattered around the target upon impact.

Sure it does. You just have to known when to initiate the process.

 

[ardnog]

The rationale for building hugely expensive small conventional strike systems remains questionable to me.

One can indeed debate the need for more weapons but if one assumes they are necessary, no current "hard kill" system is designed to engage a maneuvering hypersonic target such as a hypersonic cruise missile. Current ballistic missile interceptors are by design intended to engage targets on ballistic trajectories. EDIT: But ballistic missiles are already hypersonic, so I take hypersonic missile to imply airplane-like flight characteristics.

 

[etudiant]

No comment on the Mach number from a rail gun, but you are correct that a typical shell is several times slower. Presumably you could pack enough explosive behind it to get it going faster but at what cost? At some point the cost starts to approach that of a missile and the complexity is probably greater than a missile. If it's a ramjet-powered shell, as I've seen reported, then that solves some of the problems but introduces others. That's probably why they paused it pending the outcome of an independent feasibility study.
To the best of my knowledge, there hasn't been a flight test since X-51, though several are imminent. However, the advances in things like materials, flameholding/combustion, and ground test in the past decade have been pretty significant. Air-breathing weapons are absolutely expected to be the more challenging variety to develop (compared to boost-glide), but it's not insurmountable (or at least doesn't seem to be).
Sure it does. You just have to known when to initiate the process.

The detonation speed of high explosives such as TNT is close to 10,000 meters/sec, 2-3x that of the fastest shells at over 20,000mph. Harnessing the full explosion speed without tearing the gun apart is an unsolved problem afaik, but could allow much longer range guns.
Aiming such a gun is challenging, the 80 mile range WW1 Paris guns fired by the Germans at best hit Paris somewhere. So terminal guidance becomes essential, which requires some ability to course correct. The military benefit of such a 'golden bullet' is questionable imho.

 

[ardnog]

Aiming such a gun is challenging, the 80 mile range WW1 Paris guns fired by the Germans at best hit Paris somewhere. So terminal guidance becomes essential, which requires some ability to course correct. The military benefit of such a 'golden bullet' is questionable imho.

Price will come down as technology improves. While they may not be exconomical now, a weapon system lasts 30 or more years. Such a gun if it existed today would be a significant threat to a warship, or high value land target like an air defense radar or command center.

Now, if we're talking about smaller, shorter-range guns, missile interception and armor penetration would benefit greatly from the increased velocity of a hypersonic projectile. Whether or not this will be better than a laser is another open question.

 

[berkeman]

If it's a ramjet-powered shell, as I've seen reported, then that solves some of the problems but introduces others.

Wow, that's pretty interesting. I hadn't heard about that concept before:

https://www.thedrive.com/the-war-zo...llery-round-for-the-armys-new-super-howitzers

"The tactical 155mm XM1155 will be able to strike moving and stationary high-value targets on land and at sea," according to Raytheon's press release. "The maneuverable, extended-range airframe will be compatible with legacy and future 155mm artillery systems."

Raytheon did not offer any specific details about its design, but the ramjet will be at its core. The projectile will have to first get to an appropriate velocity for this engine to function optimally. Past ramjet artillery round designs have used rocket boosters or large conventional propelling charges to provide this initial burst of speed. The sustained supersonic flight, coupled with the fact the engine is actually pulling the projectile through the air, which helps reduce drag, are at the core of the significantly extended range capabilities.

 

[Klystron]

Detection and tracking are related but distinct problems. Detection and early warning (of attack) can be achieved with coarser methods than track; such as audio, IR and mass detectors, atmospheric disturbance and minimally processed RF; not to mention old-fashioned visual.

Tracking cruise missiles at any speed even with look-down, synthetic (images built from multiple returns) and mobile systems such as AWACS remains a nifty problem in applied physics.

When combatting cruise missiles with radar designed to track aircraft, I would recite that old poem about the 'little man upon the stairs'.

"He wasn't there again today. Oh how I wish he'd go away!"

 

[FactChecker]

So terminal guidance becomes essential, which requires some ability to course correct. The military benefit of such a 'golden bullet' is questionable imho.

How can that be questionable? Am I misreading what you mean here? IMHO, hitting the exact target has great military value and has been convincingly proven by today's smart weapons.

 

[Rive]

How can that be questionable?

I think it's about the price. There are those GPS-guided artillery shells already. But even if there were a few pieces at hand 'everywhere', as far as I know it was always kind of a celebration (with spectators!) to actually fire them.

 

[boneh3ad]

Aiming such a gun is challenging, the 80 mile range WW1 Paris guns fired by the Germans at best hit Paris somewhere. So terminal guidance becomes essential, which requires some ability to course correct. The military benefit of such a 'golden bullet' is questionable imho.

We have the technology for guided artillery right now. To me, that isn't the hard part (anymore). The quoted range combined with cost effectiveness is the big question for me.

The military value of being able to land a shell exactly on a specified target with minimal risk of collateral damage (i.e. low CEP) is unequivocally valuable. The question is just whether it's economical given the system requirements.

 

[boneh3ad]

I think it's about the price. There are those GPS-guided artillery shells already. But even if there were a few pieces at hand 'everywhere', as far as I know it was always kind of a celebration (with spectators!) to actually fire them.

It's a fairly new technology so, sure, it's not currently something you see used at scale on the battlefield. The question is whether or not it has the potential to become feasible after accounting for the the economy of scale from full-scale production. Lots of people get paid comfortable but not amazing government salaries to answer that question.

 

[FactChecker]

I think it's about the price. There are those GPS-guided artillery shells already.

Although the reliability of GPS in a war might be a current issue.

 

[boneh3ad]

Although the reliability of GPS in a war might be a current issue.

I believe we created a whole new branch of the military over this issue.