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Missile defense is NP-complete

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Re: Missile defense is NP-complete

#111

Post by maxglute »

>Hence, for one warhead, a defender can launch 4 interceptors and have a 96% chance of successfully intercepting the incoming warhead. >Unfortunately, those numbers are optimistic.

This part worth stressing, ceiling for more performant missiles, i.e. faster, terminal maneuvering, decoys are geometrically harder to intercept. Past mach ~10 terminal and functionally impossible because intercept kinematics will break interceptor airframes apart.

AFAIK there hasn't been tests (i.e. FTM series) done on anything but staged/choreographed "icbm representative" targets. Iran arsenal charitably pretty shit, including high end. Hypothetical high end missile with 10%-20% single shot probability of kill requires 20-40 interceptors for 98% confidence, before decoys, i.e. 40x6=240 interceptors for 1 missile with 5 credible decoys.

The math / economics breaks HARD with offensive missile improvements.

Re: Missile defense is NP-complete

#112

Post by nerfbatplz »

9cb14c1ec0 wrote: post #102
nerfbatplz wrote: post #75

Earlier quoted context omitted.

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.

To be clear, Trump announced that the US had destroyed Iran's air defenses, missiles and missile launch capabilities. Trump also said that the US enjoyed air supremacy over Iran and were flying when and where they wished.

Maybe one of these days we'll see a B-52 take off with JDAMs and not JASSMs but probably not, kind of scary to try and drop gravity bombs on a country that your stealth fighters can't fly over.

https://www.youtube.com/watch?v=tohttYlvFvU

Re: Missile defense is NP-complete

#113

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

How many protesters were killed leading up to it?

Re: Missile defense is NP-complete

#114

Post by jcul »

Really interesting.

Forgive my ignorance, but I thought Israel's "iron dome" offered a very effective defense.

Is this just from short distance missiles from neighbouring countries?

This article seems to indicate it's very difficult to achieve a high success rate against multiple missiles.

Admittedly I probably need to read up on this more.

Re: Missile defense is NP-complete

#115

Post by maratc »

wat10000 wrote: post #83
maratc wrote: post #32

Earlier quoted context omitted.

That's a false comparison. You want to compare between the actual options you have, which are either (a) firing an interceptor (or several); or (b) repairing the damage caused by a non-intercepted missile.

It’s far more complicated than that. The choice is often between firing an interceptor against this missile aimed at this target, or firing that interceptor against the next missile aimed at a target you can’t yet know. Because unless your production capacity far outstrips theirs, you’re going to run out first.

Not if you (a) destroy their production capacity while they don't destroy yours; (b) you destroy their stockpiles while they don't destroy yours; and (c) you've found a bottleneck on their side (launchers) and destroy it while they fail to inflict the same damage on you.

Re: Missile defense is NP-complete

#117

Post by EthanHeilman »

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…

It doesn't have to be, defender reveals everything and attacker chooses best strategy.

1. The defender could use both electronic and physical decoys, use air and sea mobile platforms that are always in motion and are difficult to track.

2. The defender can fire at decoys, to convince the attacker the decoys work when they don't.

3. The defender could mix in cheap decoy interceptor missiles that miss so the attacker concludes defenders need 10 missiles to intercept when the real number if 3 and the attacker thinks the defenders are running low on interceptors, when in fact the defenders have held most of their interceptors in reserve.

4. Defender can pretend that expensive systems have been destroyed so that attacker adapts their strategy. For instance, if your defense hinges on a small number of extremely expensive fixed X-band radars and the attacker targets them. Allow some of them to be appear to be destroyed when in fact, you have disassembled them and moved them somewhere else to use later in the war.

I see no evidence anyone is doing any of this today, I'm not making any sort of claims about deception operations in the current conflict.

Re: Missile defense is NP-complete

#118

Post by hedora »

heyitsmedotjayb wrote: post #12
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.

Preemption is a propaganda lie.

If you haven't, watch House of Dynamite.

Sadly, the Trump Administration concluded we should build exactly the defense capabilities described in the film.

They even cited it by name as a good roadmap for the Golden Dome, so I know they read the title. I guess their reading comprehension levels are extremely low.

Re: Missile defense is NP-complete

#119

Post by jandrewrogers »

Thaxll wrote: post #38
jvanderbot wrote: post #26

Earlier quoted context omitted.

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 interce…

This is wrong, for example Iran have thousands of Shahed drones, they cost almost nothing to build, to intercept just one the ratio is way way higher that 1:10. A single patriot missile is in the multi millions $ range.

They aren't using Patriots on Shahed drones. There are much cheaper purpose-built systems for that. While not practical everywhere, helicopter gun systems have proven effective in both the Middle East and Ukraine.

APKWS is quite popular and those cost less than the drones. A single fighter jet can carry 40. The Europeans are developing equivalent systems.

While not widely deployed yet, the US has operational laser-based anti-drone systems that have been shooting down Shahed class drone for a couple years now.

Ballistic missiles are more costly to deal with but ballistic missiles also cost much more.

Re: Missile defense is NP-complete

#120

Post by simonsarris »

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…

On the other hand, the best way to improve your capabilities is to use them frequently.

The Russian army assumed a state of readiness for the Ukraine invasion that turned out to be, well, less. Their special forces floundered, their logistics were (are still!?) unpalletized - using bespoke metal containers and wooden crates! Whereas the US military learned an awful lot from its (mis)adventures over the last decades.

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