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Missile defense is NP-complete
221–230 of 446 posts
Re: Missile defense is NP-complete
#222Earlier quoted context omitted.
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...
Lasers are not "all weather" weapons as far as I am aware. Clouds, snow, fog, rain, and just humidity all degrade their performance greatly.
The linked article covers that in depth, it's not implausible to punch a hole through a storm with pulsed laser of that class. Honestly we don't know enough about these systems to know their operational limits but we know weather will play a role.
Re: Missile defense is NP-complete
#223Earlier quoted context omitted.
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 mi…
I get the impression you didn't read the linked post. It goes into the details, atmospheric absorption for different wavelength, weather conditions, tracking time, interception time based on warhead hardness ratings and many more details. It's paper based, so in practice it will be more complicated and there are things it will have missed, and things we don't even know yet as being operational challenges for such systems. At the same time, it does present a compelling narrative and I'd much rather discuss individual assumptions or sources than dismiss it entirely based on a gut feeling.
Re: Missile defense is NP-complete
#224Earlier quoted context omitted.
> total manufacturing capability" is set to decline in any prolonged engagement with an Iran-like nation That was what Russia thought about Ukraine. Effectively, they needed East European tanks and munitions for the first two years, but munitions production ramped up, and now they produce more per year that what they received over two years. A resource-rich country like the Iran that is effectively fight a death war…
> And imho, while Kurds accepting to be betrayed by the US for the third time in less than two decade won't have any real long term impact, an independent Baluchistan can easily destabilise Pakistan. Not to confuse my prediction from prescription, but what prevents all the neighboring (direct or indirect over a sea) nation states from deciding to divide Iran like Germany was during the cold war? Thats not an independ…
Probably scale, a few million jews, arabs - qataris and emirates and saudi royalty is unlikely enough to deconstruct Iran, unlike Germany vs multiple comparably or larger sized regional peers.
Iran is 100m large country + 100s millions more shia core / axis of resistance supressed by small regional satraps empowered by outside forces. There are simply 10x more Muslims in region suppressed for decades under same framework where arc of history would would look kindly on Iran+co for destroying US influence and the greater Israeli project and look poorly upon satraps and compradors for failing their spiritual and moral duty of reclaiming the levant. The Nuremburg trials will be reserved for those who failed Islam for secular glitz and kindly on those who protected the faith. Iran simply has the size and spiritual/historic/civilization mandate to win the regional narrative and "moral" war versus gulf monarchs that choose to coexist with Israel. Gulf monarchs who are btw also definitionally autocrats whose contract to bribe populous with petro state proceeds goes away if this war drags on, of all autocrats they are the most likely to fall and least likely to normalize against autocrat regime change. This not to say Iran is "correct/moral" just they have scale and discourse legitimacy Germany didn't.
Re: Missile defense is NP-complete
#225Earlier quoted context omitted.
In what world would a specialized, niche, high precision, high readiness rocket meant to loft a very advanced interceptor munition into an extremely high velocity interception ever be cheap? These things are closing at like mach 20. Physics says that's hard to do. That means it's expensive. For reference, $75 million is in the realm of a Falcon 9 launch, which is a very cost optimized platform that doesn't have to pl…
Does it being very high precision or whatever mean that it must cost $75M per unit? Is it made of gold?
https://en.wikipedia.org/wiki/Advanced_Inertial_Reference_Sp...
This is what we had to build in the 60s to allow a missile to know where it physically existed precisely enough to allow it to 50% of the time hit within a circle of ~50 meters.
When you get to certain points in physics, certain energy regimes, you no longer are building machines or tools or something mass market. You are building artisan scientific instruments, and then sometimes gluing explosives to them.
Even modern laser ring gyros do not even share a dinner table with the precision and accuracy of the above singular component of the Peacekeeper ICBMs, and that was a long time ago.
"Tech" and some of the developments of the past few decades have really confused people. The miniaturization of the transistor, and building billions of transistors on a small slice of silicon is an aberration, an anomaly. Most things don't get "Better and better and cheaper and cheaper" like that because shit just doesn't scale infinitely and in general materials science isn't that precise.
For these ground based midcourse interceptors, they have to precisely loft the interceptor package at an incoming projectile. They have to shoot a bullet with a bullet, except the target bullet might even be moving around a bit, and your ability to precisely quantify the exact parameters of it's position and velocity is already limited. Is your position and velocity measurement an inch off? Two inches? Is that too much?
How well have you quantified the thrust of your rocket engine? THIS specific rocket engine, not a random one from the batch. Will you be off in a direction by a few meters per second? That might be enough to scuttle your interception.
IIRC this is the interception payload, a kinetic kill vehicle:
https://www.youtube.com/watch?v=KBMU6l6GsdM
Then, are any of those nozzles slightly less smooth than they should be? That's a miss. Did propellant slosh in an unexpected way? That's a miss, Chicago is now a smoldering crater. Incoming round bounce your rader signal in just a slightly different way than you had the data to know about? Miss, San Fransisco now has significantly cheaper real estate. Chaotic properties of hot expanding gas slightly different than your simulation in the unluckiest way? Miss.
You have to exhaustively inspect, reinspect, quality control, test, simulate, retest, catalogue, document, every single component. You have to be able to predict, almost perfectly, how every single component will act and perform in a situation you will never get a test for.
High energy physics is always going to be hard, never cheap, because high concentrations of energy are literally what the universe itself is trying to reduce. The rules of reality itself are against you.
A creator on youtube named Alexander the Ok has done wonderful videos on a lot of the technology that goes into these systems, especially older, less classified systems.
Re: Missile defense is NP-complete
#226Earlier quoted context omitted.
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"--…
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…
I don't see how drones don't make all conflicts into WW1. 100 Billion dollars buys about 3.3 million Shaheds assuming the manufacturing is not made more efficient. There are many questions on whether its possible to spend 100 billion dollars on Shaheds, or launch all of them. But this is more than enough to destroy any logistics and transportation infrastructure necessary for a ground invasion.
There are many many countries who can afford 100 billion dollars for stored military equipment that has a long shelf life. The US makes ~50k artillery shells a month at a cost of about 10k per shell.
Re: Missile defense is NP-complete
#227Really 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.
There are multiple tiers of missile (and ballistic missile defense). Especially with ballistic missiles, the longer the range, the faster the inbound warhead will be in the terminal phase (roughly). So longer range ~= faster meaning more difficult to intercept. "Iron Dome" is the name generally used to describe Israel's lowest tier set of defenses. Very roughly Iron Dome is designed to defend against stuff that you c…
Interesting stuff, thanks for the long and detailed response.
Re: Missile defense is NP-complete
#228Earlier quoted context omitted.
In a direct conflict with China, the ICBM exchange would destroy the F35s on the ground.
China doesn't seem to think so. China believes they need to fight those F35s in the air. Why would the opening salvo be ICBMs?
To deny the US the use of any nearby airfields (Okinawa, several others in Japan an Philippines). This will limit US airpower to carriers, which are few and sinkable.
Of course, China wants to be able to fight those F35s in the air - to mitigate the damage they can do to them (while the F35s still have airfield/carriers to land on) - also in order to make it easier to sink those carriers.
Still, you can bet that all US nearby airfields would be peppered very early in the conflict.
Re: Missile defense is NP-complete
#229Earlier 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…
I don't see how drones don't make all conflicts into WW1. 100 Billion dollars buys about 3.3 million Shaheds assuming the manufacturing is not made more efficient. There are many questions on whether its possible to spend 100 billion dollars on Shaheds, or launch all of them. But this is more than enough to destroy any logistics and transportation infrastructure necessary for a ground invasion. There are many many co…
> US makes ~50k artillery shells a month at a cost of about 10k per shell.
50000 * 10000 * 12 is 6B/year. I was surprised, but I suppose that passes the smell test for a ~1T/year defense budget.
Re: Missile defense is NP-complete
#230Earlier quoted context omitted.
Iran has successfully targeted countless bases around the Middle East, a lot of this news simply isn’t being covered. Most of these strikes are on static assets like radar, depots, and other structures. If you are thinking about the F35s, strikes that hit runways are repaired in a matter of hours. As for the F35s themselves, they are constantly on the move or simply kept in the air. Service and storage is done on rem…
That's certainly what Iranian propaganda is saying, as if everybody is censoring their great successes. Fact is there is no meaningful reduction in Israeli attacks, while Iranian launching ability had greatly suffered. So these air bases are probably not being hit. Apart from it in the era of OSINT satellite imagery, it is no issue to publicize such damage, I don't know of any such imagery Regarding the gulf, there t…
> Apart from it in the era of OSINT satellite imagery, it is no issue to publicize such damage, I don't know of any such imagery
Not sure about other providers, but Planet Labs has applied a 14-day delay to satellite images of the middle east.
https://www.reuters.com/business/aerospace-defense/satellite...