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Missile defense is NP-complete

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Re: Missile defense is NP-complete

#21

Post by 1234letshaveatw »

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…

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

Re: Missile defense is NP-complete

#22

Post by biker142541 »

SegfaultSeagull wrote: post #20
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…

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

History would suggest otherwise; rarely is this ever the case.

Re: Missile defense is NP-complete

#23

Post by gos9 »

busterarm wrote: post #5
delichon wrote: post #4

Add multiple decoys and the missile math tends to become an argument for the importance of preemption. Han shot first for a good reason.

Careful. Preemption takes many forms, some of them many would find unpalatable.

Unpalatable preemption is generally better than reentry vehicles coming down your chimney.

Re: Missile defense is NP-complete

#24

Post by srean »

Game theory would be useful for these kinds of modeling.

Perhaps the government should have and advisory body that employs the smartest mathematicians for running these scenarios. Of course a lot of randomness needs to be modeled too. Wonder what would be a good name for such a body :)

Paradoxically, if anyone leaks unpalatable information from the inside that would be a problem for the government.

https://en.wikipedia.org/wiki/Daniel_Ellsberg

https://en.wikipedia.org/wiki/Ellsberg_paradox

https://en.wikipedia.org/wiki/RAND_Corporation

Re: Missile defense is NP-complete

#25

Post by cpgxiii »

dboreham wrote: post #2

It's been known since the 1960s that effective anti ballistic missile defense is impossible.

There are several different levels of ballistic missiles.

ICBMs, for which the GBI is intended, are the most challenging to defend against and show the least interceptor success.

In contrast, we do have some pretty definitive evidence that theater and "lower" MRBM/IRMB ballistic missiles can be intercepted successfully. If you define "effective defense" as "most missiles that would cause damage are intercepted", then it is clearly possible with current technology. If you define "effective defense" as "all missiles are intercepted", then it remains beyond the current technology.

Re: Missile defense is NP-complete

#26

Post by jvanderbot »

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…

Ah yes, but then you also have to add GDP + targetting/defense radii.

Great Britian alone has 10x the GDP of Iran. So an interceptor costing 10:1 is (at first approx) breakeven just for GB, who would have to intercept much less than the total manufacturing capability of Iran anyway.

Then you have every rich nation surrounding Iran as well. Let alone the USA who cannot be reached but throws their weight behind interceptions.

And finally "total manufacturing capability" is set to decline in any prolonged engagement with an Iran-like nation, but GB, western EU, USA, et al, are likely to only increase production if an engagement played out.

The math looks catastrophic on paper at 10:1, but I sincerely doubt that's the right analysis. An interceptor is worth what you're protecting, not what the attacking asset costs, so long as you can keep producing them.

Re: Missile defense is NP-complete

#27

Post by quotemstr »

The sole mention of directed energy:

> Directed energy has been proposed as a cost-effective alternative, but introduces its own scheduling constraints — dwell time, platform coverage, atmospheric degradation — with similar scaling issues

The author is doing the thing where a writer tries to bamboozle the reader into a conclusion without having to prove it by overwhelming the reader with nouns. Life is too short for shitty gosh gallops.

Re: Missile defense is NP-complete

#28

Post by bluGill »

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…

There are too many potential attackers though, and not everyone is sane. So you don't really get a choice about it. The cost of the interceptors needs to be considered in relation to the cost of what it protects. If the interceptor means an attacker doesn't kill my kids then it was worth the cost. If the interceptor keeps a multi-million dollar building around then interceptor at a million dollars is still cheap, even if the missile it takes out was only $100.

Yes you should use diplomacy to ensure war doesn't happen in the first place. However if it does: they will send cheap drones and missiles at you in large quantifies.

Re: Missile defense is NP-complete

#29

Post by myrmidon »

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…

This is absolutely true, but there is a strong counterpoint: You also learn the limits of your own systems and how to operate them most effectively yourself (and better than adversaries can, too).

Just to pick a recent example: Russian air defense in the early stages of the Ukraine war was dismal (more specifically: defense against big, slow drones like Bayraktar), despite having sufficient AA capability "on paper"-- the war allowed them to visibly improve.

I'd expect much more value from validating and improving your equipment and its handling than the actual "cost" of revealing its capabilities to adversaries in almost every conflict.

Re: Missile defense is NP-complete

#30

Post by phkahler »

gos9 wrote: post #23
busterarm wrote: post #5

Earlier quoted context omitted.

Careful. Preemption takes many forms, some of them many would find unpalatable.

Unpalatable preemption is generally better than reentry vehicles coming down your chimney.

The problem there is you can't prove anything would have come down the chimney if the preemption is successful, so people will still be unhappy.
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