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Comment by iamwil | Hacker News Reader

My first job out of college was working for a lab that did stuff for Air Defense. We did stuff like missiles that shot down other missiles for the Navy. Anyway, in my naivety, I asked the more senior engineers why we don't shoot missile plumes. Lots of cheap missiles in the hopes that one hits. (I didn't mention the idea was from watching anime.)

They told me that the backfire from the exhaust of one missile might ignite the one behind it if we did stuff like that. That said, I've seen videos of ships firing missiles in relatively quick succession. Just not like the Itano Circus, however.

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The UK Starstreak anti-aircraft missile has 3 submunition darts to improve hit probability. There is nothing wrong with the idea per se, you can design around backfire. The Metal Storm gun has multiple munitions stacked in the same tube.

I figure the problem is more that it’s hard to scale down missiles to the point the plume would make economic sense.

One well-guided missile can be infinitely more effective than 1000 poorly-guided missiles.

Unless you are seeking a penetration aid against defenses, I don't see much point. There are far cheaper ways to deliver mass on target if you simply want to spam the enemy.

Depends on what you're defending against. Drones are effective because they're cheap so they can be sent in large numbers to overwhelm air defense even if each individual drone is an easy target.

The type of cheap drones that can be sent in large numbers lack the range to attack ships unless they're really close.

Just take a bigger drone truck to get them there.

happy Protoss Carrier noises

I’m absolutely in favor of a massive airship spewing hundreds of drones :)

“Cheap drone” doesn't need to be off the shelf quadcopter drone, fixed-wings custom drones like the Iranian Shahed 126 are still dirt cheap compared to typical anti-ship missiles.

Those lack the sensors needed to detect and track a moving ship. Good sensors are expensive, and consume a lot of power.

But you don't need one sensor per drone, but one per swarm with the same target (and any kind of data link between members of the swarm). And by the time the swarm is within reach of the protection weapons of the target, it's probably close enough for the fairly basic sensors onboard of every drone to be able to work on its own if the target drone is destroyed (for instance: GNSS up to the last know position of the ship, and then just computer vision at close-range).

A ship isn't exactly a small target. You could probably track it just fine with a satellite and update the target GPS coordinate of the drones manually. An aircraft carrier only moves at 55 km/h maximum.

Nope. Ships are very small targets in very large oceans. Have you ever even been on a boat out of sight from land?

Reconnaissance satellites will be the first casualties in any future high-end conflict. Modern militaries have to plan around the expectation that their space-based platforms will be unavailable or severely degraded.

Radar ocean reconnaissance satellites can detect ships under any weather conditions but they are are large, heavy, expensive, and can provide only intermittent coverage. Smaller satellites with optical or IR sensors can potentially provide more coverage but are less effective at night or with clouds.

Apparently China is already tracking U.S. aircraft carriers via satellite: https://www.scmp.com/news/china/science/article/3177079/chin...

And sure, you need to wait for a clear day, but that doesn't seem like too big an obstacle. Also, while space-based platforms will be targets, it's unclear how effective counter measures are. Identifying targets is challenging and deploying replacements is worth the cost if you can eliminate a large portion of an adversary's naval power.

This is nothing new. The USSR was tracking US aircraft carriers via satellite since the 1960's. China is only now catching up.

Carriers are certainly vulnerable to an extent, but detecting one with a satellite is only one step in the kill chain. Carrier strike groups already carry some limited anti-satellite weapons that can hit targets in LEO. There is an active arms race underway by the superpowers to boost those capabilities, and also (as you stated) to develop a prompt launch capability to replace satellite attrition losses within hours rather than scheduling launches years in advance.

That's basically how most Anti-ship missile work: you give them GPS coordinate for the rough location and then the missile uses an active radar homing system for terminal guidance. (You want the missile to keep quiet as long as possible anyway, to avoid being detected and reducing the time the crew has to react to the threat).

Apparently, the oceans do a lot of radar scattering that makes it harder to spot ships from the guidance systems of missiles. Not sure what the state of the art is nowadays though.

So far. There are many ways to make longrange, fuel efficient flying things.

What are those ways? Do they also allow for large sensors and warheads?

Submunitions think ICBM or cluster bombs. There’s a tradeoff, because smarts means less room for the deadly bits.

Some kind of smart bomblets could be very effective vs traditional military bases which use sandbag walls to limit how effective traditional munitions are. Smarter drones could be more useful when trying to clear a forest.

Anti ship missiles on the other hand need large warheads to be effective. But launching multiple is preferred due to CIWS/point defense weapon systems.

Smart submunitions launched from drones have been a thing for decades.

https://news.northropgrumman.com/news/releases/bat-submuniti...

Yea, though BAT is designed for armored vehicles not personal.

Military UAV’s are also huge. I assume when people are thinking drones they are downscaling to the 1-10kg range not full sized aircraft with a 50 foot wingspan.

Just being the overconfident random internet person with ideas:

launch 100 vehicles, slow flying, potentially with gliding capabilities, converging from all directions onto a target at the same time, ditching main wings and piston engine at the last minute, firing a rocket to gain speed, and overwhelm air defence by sheer numbers. Combine low-flying attack profiles with "dive-bomb from above". Large sensors can be mitigated with mesh-networking between vehicles and sensor fusion, maybe different kinds of sensors on different vehicles. Slow-flying means they can carry heavier warheads thanks to more lift and less drag.

If slowly circling at high altitude, you also tie up resources keeping track of them.

Quantity is its own quality, and all that...

this is all without even bringing "AI" into the mix, but if you could, you can give them "goals" instead of targets.

It is possible in principle to build a loitering cruise missile with those features. It will not be small or cheap, at least not if you want something with the range and endurance to seek out and attack a ship on the open ocean in any weather conditions. Add up the cost and weight for all of those components you listed.

As a point of comparison, the latest Block IV Tomahawk missiles already do most of what you described. They cost about $2M each and weigh about 1.5 tons. Only the largest warships can potentially carry 100 such missiles.

Russia has used small, cheap cruise missiles like the Iranian Shahed-136 drones with some limited success against Ukraine. In a naval conflict such drones could have some value as harassment weapons against surface vessels operating in the littorals. But those drones are useless against moving ships over the horizon.

Those Shahed drones are too small. I'm just thinking from first principles, if an ultralight plane has a range of 500km and has a 100kg pilot in it which could be subbed for a warhead, you could do an awful lot of damage with hundreds of such things in the air.

Your numbers are way off. Ultralight airplanes don't have ranges anywhere near 500km, nor do they have the payload capacity to carry the necessary sensors and associated electrical generator. Ultralights are also barely faster than surface warships, and are too flimsy to operate in severe weather. Seriously, you guys need to quit watching silly scifi cartoons and do some actual math.

The Sadler Vampire was/is 100 kg something dry, 250 kg loaded and a range of 500km. How much power do you need for sensors anyway? Even with 100 kg for fuel, that's a lot of weight left for warhead and electronics. That's for a straight conversion of a COTS design. I'm sure corners can be cut for something which will only run for a few hours and never fly again.

But sure, I'll go back to my cartoons again. /s

> One well-guided missile can be infinitely more effective than 1000 poorly-guided missiles.

Only true if it can target a high value unit or concentration of units which value exceed the missile cost.

Anti-air is a different scenario than artillery. Startreak targets are fast evading and employ countermeasures that attempt to trick the missiles target acquisition. I'm out of my depth but I believe the justification for the 3 missiles was improving the odds of hitting the target as that add redundancy and kind of triple the resolution of the targeting systems where a single missile with better electronics might be less effective and more costly.

The question I have is: can you scale down the well-guided missile? I thought guidance is mostly an issue of fast chips and well designed software. But perhaps you need big missiles if you want them to fly fast and have a lot of range.

Talking about anti-air of course. Lots of small missiles aren’t going to be effective against hardened ground targets.

Sensors matter a lot for guidance. In order to build an effective radar guided missile it needs a fairly large array. So in practice the minimum missile diameter ends up being something around 7 inches. Long range surface to air missiles have to be much wider than that.

Data links also make a big difference. So the missile needs another fairly large antenna to receive guidance cues from other platforms.

    But perhaps you need big missiles if you want them to 
    fly fast and have a lot of range.

I'm just a layperson but this has always been my understanding. Modern air combat is all about firing from beyond visual range, so I think they optimize pretty strongly for that.

See my other answer, though - air to air missiles ARE generally (always) proximity fuzed. They don't need to precisely impact the target, they just need to get close.

More then that, air-to-air missiles generally are designed to blow a load of metal shrapnel through whatever they "hit": so there's a problem where if you're fleeing from a missile and it explodes behind you, even though it "missed" the payload can still hit the plane it was chasing if the plane doesn't change trajectory.

For many air-to-air and ground-to-air missiles, we cheat and improve the hit probability another way: proximity fuses.

Example - https://en.wikipedia.org/wiki/AIM-9_Sidewinder

They detonate near the target rather than impacting it directly. This greatly improves the chance of success. Jets are fragile, so this is almost always sufficient to take them out of commission.

It makes far more sense to do something like that in space instead of in the atmosphere. You could spread the missiles out a little before ignition. But you would also need some kind of swarm logic and tracking to make sure they don't bump into each other.

Ostensibly the Generation 2 Ground Launched Small Diameter Bomb munitions will do something like this - i.e. they're capable of independently acquiring targets, and then de-conflict the target acquisitions to ensure they don't all track on the same one.

Basically the idea being that you fire a whole lot of them at the enemy trench somewhere over there, and on terminal approach they independently assign themselves to specific interesting looking targets.

Sort of like the CBU-97, it's mission profile is ridiculously insane. First 10 sub munitions are ejected out. A parachute slows the downward movement of the sub munition carrier. A rocket then spins it up to a high speed where it starts flinging shaped charge skeet at vehicles in range. these skeet then detonate once they detect they are above the vehicle.

My reaction was the same as when I first learned about how jpl was going to get the curiosity rover down to the surface of mars with a rocket crane. "There is no way something that complicated would actually work."

https://en.wikipedia.org/wiki/CBU-97_Sensor_Fuzed_Weapon

Must’ve been a fun job training them what a valid target is :/

Probably pretty easy. Anything that's not flat terrain, kinda irregular in shape, and a fixed distance from another target, e.g. 3 meters or something, to ensure a reasonable spread.

After seeing videos of n-copters dropping grenades on soldiers in the Ukraine-Russia war, I do think there is evidence of a move to small and cheap technology.

> That said, I've seen videos of ships firing missiles in relatively quick succession. Just not like the Itano Circus, however.

Saturation attack is indeed a tactic used. The idea is to time your attack for missiles to arrive on your target at the same time independantly of when they are launched and of their trajectories.

Also, a missile hit for anti-missile defense probably doesn't look like what you expect. There is no need to reach the incoming missile spot on. The goal is to explode in its vicinity preferably slightly in front of it. Incoming missiles are fast enough that impacting either debris or the explosion shockwave will disable them if they are close in a radius which is not that small.

It's not a bad idea. It's just a practical reality of their interaction with each other that causes a problem that's hard to workaround.

The challenge with "lots of smaller missiles" is really range, I think. You want to hit the target from as far away as possible. That takes fuel, which puts limits on how small you can go.

The longest-range version of the AIM-120 has a range of 160km, and missiles under development promise even longer ranges than that, so that kind of tells you what they prioritize.

One tangential thing to understand is that air to air missiles are proximity fuzed. They don't need to precisely impact their target, they just need to get close.

I think this is mostly because longer range sounds like a great thing when you don’t have hundreds of missiles to defend against.

It’d be nice if there was a similar defense against saturation bombing.

    I think this is mostly because longer range 
    sounds like a great thing when you don’t have 
    hundreds of missiles to defend against.

You're optimizing for the wrong thing. Today's missiles are extremely lethal and good at finding their targets. The challenge is getting close enough to launch them without getting killed by other aircraft or ground-to-air defenses. Ground to air defenses are getting cheaper and more lethal all the time.

If you take human pilots out of the equation, obviously this changes things (your aircraft can be cheaper and you worry less about losing one) but not entirely. You still have to figure out how to deliver the missiles without getting shot down and while remote piloting is cool, it's still subject to jamming and such.

Minus the cool swirly anime effects, pilots certainly do have the option of firing multiple missiles at a given target. Fire one missile from beyond visual range, wait, and then fire another one. This is very common in DCS, which is obviously not reality but is a pretty decent simulation according to a lot of actual pilots. Not sure what actual fighter pilot doctrine is there and if that's a real world practice as well.

I was thinking more about Ukraine, not an anime style missile swarm :)

You need defensive missiles that are significantly cheaper and easier to produce to stop your larger adversary from raining death down everywhere.

It’s nice if you have a missile that you can use to intercept any incoming dumb missile anywhere in 300km, but not if your missiles cost 1M and theirs cost 100k.

Doesn’t a howitzer shoot multiple middles at once? (Or are they shot in quick succession?)

Quick succession. Due to the projectiles taking a while to arrive on target (especially for high-arcing trajectories) this gives you the effect of multiple projectiles arriving simultaneously on target: https://en.wikipedia.org/wiki/Artillery#Multiple_round_simul...

It also places some demands on fire control and loading to achieve the high fire rate; I'm not sure manually-loaded howitzers are capable of that in general (e.g. the German PzH 2000 automates everything from loading shells and propellant to firing).

Thank you for calling it by it’s proper name and not “Anime Homing Missiles”

The MX sort of did that on the reentry side.

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