As an alternative formulation of the same problem, maintaining peace has linear cost, completely solvable in linear time and rewards are unbounded for all parties.
Missile defense is NP-complete
131–140 of 446 posts
Re: Missile defense is NP-complete
#132Two 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.
What Iranian drone did a trillion dollars in damages?
I'm not saying the general thrust of your argument is wrong, quite the opposite. But that's a big number for one drone.
Re: Missile defense is NP-complete
#133Earlier quoted context omitted.
There is an assumption here that the value in improving defenses is the same as improving offensive weapons. That is not the case in the assymetry that drones provide and Russia is the first example. Russia has not been able to improve AA capabilities to the point where it's "safe", for any definition of the word, neither has Israel. Israel and Gulf states often tout over 90% interception rate yet it's really at the…
Air defenses do not need to be 100% effective to be... effective. Russia cannot keep Ukraine from targeting their oil infrastructure, yet here Russia is, still fighting on. Ukraine cannot prevent Russia from targeting their energy infrastructure or apartment buildings, yet here they are, still fighting on. If we're talking about strategic/civil air defense, then you must figure out what's tolerable to your population…
In the Ukraine-Russia war, air defense is used to deny air superiority to the enemy. Just a few days ago, Ukraine blew up Russia's helicopters in the air with drones. It's not the successful hits that matter, it's the capabilities that you deny by posing that credible threat.
Re: Missile defense is NP-complete
#134Earlier 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).
OK, assume infinite resources, but the attacker only has one missile, and the defender only has one interceptor.
Optimal strategy for the attacker: Figure out how fast the interceptor can reach your missile, and have it split into a dozen warheads on different trajectories a mile before that. Include the blast radius of the interceptor in the calculation in case the defender decides to set of high-altitude nukes to defend itself against your missile.
The non-proliferation treaties we just pulled out of banned multi-warhead ICBMs decades ago because there's no feasible counter-move. That's bad for the missile business.
Back in reality, the attacker just builds 100,000 conventional drones, and 1 identical looking one with a nuke in it. Eventually, the defender runs out of interceptors, so the intercept probability trends to 0. At that point, the attacker sends the nuke without varying the behavior of the conventional drones.
Re: Missile defense is NP-complete
#135What happened to Iron Beam / lasers and those vaunted "space lasers" dubbed "star wars"?
The US has deployed operational anti-drone lasers for a few years now, though not widely. They are still quite new but they have several kills. This is probably operational field testing for fine-tuning the design prior to producing them at scale though.
Re: Missile defense is NP-complete
#136Earlier quoted context omitted.
Did I miss this ? Missing from the discussion is that Iran's cluster munitions in each single missle have absolutely overwhelmed Israels defense and would likely do the same to US military as well. Also to consider, Iran's $20,000 drones versus our $1 million dollar interceptors.
Cluster munitions are great against infantry in open field; less so against population centres equipped with advance warning systems. As it stands, they fail to even cause the damage worth offsetting by firing interceptors. The damage these inflict on Israel is not unsustainable, and they don't do much to create deterrence. Given a choice of conventional 500-800 kg warhead or cluster munitions warhead, I think that t…
>The damage these inflict on Israel is not unsustainable, and they don't do much to create deterrence.
Has there been a study on this? What is the GDP loss of having however many Israelis go to bunkers due to incoming ballistics instead of working ?
If a trash cluster missile that costs 100k USD to build causes 1mio USD worth of GDP to not be produced (numbers completely made up) then it's very worth it.
Re: Missile defense is NP-complete
#137Why does a ground based interceptor cost $75M? High idiot index?
$1M, but we can only make 600 / year, globally.
Re: Missile defense is NP-complete
#138>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 in…
Lasers. No really, near-future laser systems with adaptive optics and good spotting - for example distributed SAR satellites - dramatically shift that balance [0]. [0] https://toughsf.blogspot.com/2025/05/the-laser-revolution-pa...
I doubt a MW laser can reliably intercept a reentry vehicle. A lot of energy is lost through the atmosphere when intercepting a warhead in space, from a land based laser. Once it reenters the atmosphere there might not be enough time. You also need to burn through the heatshield that the warhead is equipped with for reentry.
Even if you can can deliver enough energy for long enough, there is no fuel to burn and it might not be easy to detonate or disable the warhead.
For ICBMs, one idea was to use orbital, nuclear powered lasers to hit the missile on the boost phase.
But that's very much not near-future.
Lasers might still be useful for rockets, drones and cruise missiles of course.
Re: Missile defense is NP-complete
#139Re: Missile defense is NP-complete
#140Earlier quoted context omitted.
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.
That's true, but feels very much like "draw the rest of the owl." And even if you can do it, you'd have to do it against any country that starts to build this capacity that you think might somebody potentially use it against you, even if they aren't currently, unless you're confident that you can destroy their launchers and stockpiles so quickly that they can't be used in any significant number. (And if the USA couldn't manage to do that to Iran....)