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Missile defense is NP-complete

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Re: Missile defense is NP-complete

#101

Post by hedora »

wat10000 wrote: post #89
jvanderbot wrote: post #42

Earlier quoted context omitted.

No, what I said is not wrong just because there exists other things to intercept, that just changes the ratio. You still have to consider whether it's worth it to spend a patriot missile to intercept a drone, vs letting the drone hit, say, a billion dollar radar installation or a dozen troops. On the manufacturing side, nobody said that all drones are intercepted with patriots. You have to look at the avg cost to int…

For one thing, the entire world economy is not even close to 1000x Iran’s.

$1M / $30 (patriot cost / drone cost) is only 33x. The US economy is about 31x larger than Iran's. So, to first order approximation, we could build enough patriots to sustainably stop their drones.

However, we haven't converted our economy to just producing Patriots. We can only produce 600 / year. Drone production rates are orders of magnitude higher than that.

As for second order effects, the interception probabilities are less than one, so in this world where we're producing a million patriots per year, tens of thousands of drones (at minimum) are hitting their targets. On top of that, the offensive drones are more easily transported + retargeted, so the patriots would need to be stationed pretty much everywhere, and their adversary chooses where the attacks actually happen.

The only winning move is not to play.

Re: Missile defense is NP-complete

#102

Post by 9cb14c1ec0 »

nerfbatplz wrote: post #75
SegfaultSeagull wrote: post #20

Earlier quoted context omitted.

Or perhaps they will learn they are outmatched, lack the resources and technological capabilities to compete, and deterrence will have been established.

The Iranians just hit an F35 with a proverbial box of scraps they put together in a cave. The Chinese military must have experienced collective euphoria when they saw that.

To be clear, that F35 was being incredibly careless, flying low in broad daylight. All the stealth features of an aircraft are useless if you can look at it with your own eyes. In any conflict with China, F35s would not be flown that way.

Re: Missile defense is NP-complete

#103

Post by hollyhotdog »

jsw97 wrote: post #8

The author explains that this problem is actually adversarial, in the sense that the attacker gets to observe defenses and allocate warheads and decoys accordingly. Thinking of our current circumstances, this suggests another cost of war: our offensive capabilities, as well as our defensive capabilities become more observable. Our adversaries are studying our strengths and weaknesses in Iran, and they will have a muc…

[dead]

Re: Missile defense is NP-complete

#104

Post by testaccount28 »

falcor84 wrote: post #80
gzread wrote: post #48

Earlier quoted context omitted.

More like the USA starting wars against countries, and those countries not immediately surrendering, to which the USA is shocked.

I think that there's a more general issue here with the US and the West in general having a mindset built up on playing Risk and Civ, which considers the foreign country as a whole as their opponent, whereas in practice, the adversaries are a multitude of individuals, for almost none of whom a surrender is the rational choice, especially (as sibling comments pointed out) when part of their reasoning and authority is…

to be clear: your claim is that the us military is misinformed because key constituents have played too many board games?

does hearing it back like that make it seem absurd to you as well?

Re: Missile defense is NP-complete

#105

Post by adampunk »

energy123 wrote: post #98
adampunk wrote: post #93

Earlier quoted context omitted.

https://en.wikipedia.org/wiki/The_bomber_will_always_get_thr... That’s the steady state. Interceptors are expensive; missiles are (relatively) cheap. There’s no sine wave or cat and mouse game. If you’re trying to defend against a peer, missile defense loses.

I'm talking about interception probability, not the relative cost. I get that interceptors will probably be more expensive indefinitely (unless we start putting lasers into orbit to get around atmosphere, or something unexpected like that).

Well there the cost plays a part! It’s not independent. If I can build 1000 missiles for every 1 interceptor, the probability of interception hardly matters.

This actually was why we planned to put lasers in space: the economics of one nuclear-pumped laser reflected through Unobtanium were better than any other interceptor. And even that if the effect worked (it didn’t, they could not prove lasing and fired an engineer who blew the whistle on that), the system could be defeated by a staggered salvo.

Re: Missile defense is NP-complete

#106

Post by contravariant »

> Note that a more complete model would multiply each term by P(track)_j — the common-mode detection-tracking-classification factor developed in the previous section — but the standard WTA formulation assumes perfect tracking.

I'm not sure that is a useful model, or more complete. I don't think you can assign interceptors to undetected missiles, so considering their effect on the value is rather pointless. It's effectively a sunk cost.

Multiplying with the probability also makes no sense from an optimisation point of view. Why would you assign lower value to a target about to be hit simply because you were unlikely to detect the missile?

The tracking probability only shows up in the meta game described at the end, where one side is trying to optimise their ability to hit valuable targets and the other is trying to optimise their ability to prevent that from happening.

Re: Missile defense is NP-complete

#107

Post by hedora »

energy123 wrote: post #63
owenmarshall wrote: post #16

Two more sobering axes to introduce: cost and manufacturing capability. Numbers are hard to find for obvious security reasons, but using the numbers most optimistic to the defender[0] suggests an adversary using a Fatah type hypersonic is spending 1/3rd the cost of an Arrow interceptor, and is launching missiles that are produced at a much faster rate. Interception is deeply asymmetric in favor of the attacker. [0] h…

The best missile defense is offsense: degrading the launchers, stockpiles and defense industrial base, with cheap stand-in munitions after SEAD, leveraging air and intelligence superiority. Expensive interceptors are only a stop-gap that buys you time for the offensive degradation. Expensive stand-off munitions, likewise, are a short-term stopgap until SEAD is complete.

Offense doesn't work at scale.

As the cost of drones goes to zero, the expected damage you take is roughly proportional to how much you have to lose. This means larger / richer economies cannot win these sorts of wars. To see what I mean, check out this desalination plant map:

https://www.theguardian.com/world/2026/mar/23/iran-threat-to...

It doesn't help if your commander in chief is incompetent and your invasion strategy involves treating desalination plants as legitimate military targets.

Of course, blowing up desalination plants in the middle east don't hurt the US all that much, but blowing up industrial supply chains does. We're something like 4 days away from a global chip manufacturing industry shut down (barring some logistic miracle, since we recently sold off our strategic helium reserves).

Re: Missile defense is NP-complete

#108

Post by 1234letshaveatw »

lejalv wrote: post #53
1234letshaveatw wrote: post #21

Earlier quoted context omitted.

That seems like an acceptable trade off to get some real world experience with what works and what doesn't with regards to massed drones and swarming. There is a lot we can learn in this conflict with relatively low stakes

Stakes for whom? >100 kids got murdered the first day of this "low stakes" war

The USA

Re: Missile defense is NP-complete

#109

Post by owenmarshall »

hedora wrote: post #59
owenmarshall wrote: post #16

Two more sobering axes to introduce: cost and manufacturing capability. Numbers are hard to find for obvious security reasons, but using the numbers most optimistic to the defender[0] suggests an adversary using a Fatah type hypersonic is spending 1/3rd the cost of an Arrow interceptor, and is launching missiles that are produced at a much faster rate. Interception is deeply asymmetric in favor of the attacker. [0] h…

Currently, we're using $1M interceptors to take out $30K drones. This asymmetry is here to stay. The end game probably involves At that point, it turns into a logistics problem that's much easier for the attacker than the defender. Iran's already demonstrated that one successful drone can do $100B-1T in damages, so a hit rate of 0.1% means a 1:100K cost:damage ratio.

This leans towards my belief that the US is fundamentally fighting last century's war against adversaries that have _massively_ evolved.

Look at the Ukranians: they are currently fielding an entire suite of counter-drone tech: fast pursuit systems to hit Russian drones on launch, cheap FPV drones for last-mile intercept, integrated radar/acoustic monitoring to target and respond to launches... and of course, the Russians are responding with IR floodlights and air to air launchers on their drones, or even just launching a bunch of cheap foam decoy Gerbera's in the middle of their Shahed's to soak up intercepts. Meanwhile, the front lines are basically static -- any infantry from either side that tries to go into the kill box gets picked off by loitering drones.

And the best the US can field today is "$1mm per Patriot" or "cover a tiny area with Land Phalanx (which also costs something like $4k/second burst)".

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