> you have to stockpile interceptors anyway, even though they're not nearly as effective as a good attack
Strange, I keep hearing from experts that attacking is 10x as costly as defending.
Strange, I keep hearing from experts that attacking is 10x as costly as defending.
b) A human defender can hunker down in a safe space and shoot at attackers. The attackers need to move and are more vulnerable
If your interceptors are good eventually the enemy is going to give up on that attack mode. - you have more incentive to defend than they do to conduct useless attacks.
Ukraine's interceptors for cheap drones are drones that are even cheaper and so advantage defender.
For a facility that Ukraine has decided would cause $10m in economic damage if hit by a Russian drone, how much should Ukraine spend on interception for that site to not make it worth Russia's expense to target it? Let's assume a Russian drone is $100k (current estimate in news for Geran-5 jet-powered drones). But Ukraine can build their Bars interceptor drone for half the cost at just $50k (low estimate from public rumours/reports). It wouldn't be worth Russia's expense to send more than 100 drones in a salvo at this target. For Ukraine, they should defend the site with $5m worth of Bars interceptor drones, assuming a very favourable 100% success rate (actual reported success rates are reported by media to be just 30%). Russia has now made every $10m facility in Ukraine cost $15m (+50% increase).
The defender is essentially forced to find a 10:1 or better cost advantage for their interceptors vs. incoming drones. This is hard to do when an interceptor and attack drone are substantially the same except for larger fuselage (cheap), larger fuel tank (cheap) and larger engine (possibly cheaper than making a small engine).
And perhaps that is the reason Russia and Ukraine are largely focussed on attack rather than defence in the hope of being first to cripple the other's economy and supply chain for munitions.
This is likely a a flattened curve after you enter ballistic missile territory.
1. US+Israel economies have a 100:1 size advantage over Iran's economy.
2. Israel is a very small area to defend, dramatically reducing the cost of anti-ballistic missile defence required. As little as 4 missile defence launch sites may cover the entire country.
Perun's video on the cost effectiveness of missile defence vs. attack is more focussed towards the economics of defence of an expansive country or region such as the United States, Saudi Arabia or the gulf region generally, where many missile defence sites would be required. Israel is a bit of an exception due to the small area needing to be defended.
Another minus specifically for Iran in the Iran/US+Israel war is being forced to build underground factories at much greater expense than an above-ground factory for Israeli interceptor missiles. I don't think analysts have been considering this long term cost in their cost comparison ratios. However, for both Iran and Israel--they're importing a lot of the components and materials from overseas anyway.
Defenders have a big advantage because they can choose a good position and hide. Often this means they can catch attackers by surprise, and so eliminate the entire attack.
Defenders have time to fortify their position - even if the attacker knows where they are, the attacker needs to run up to a fortified position to take it.
Defenders often know where others are and plan overlapping lanes of fire. If someone is attacking you, the next position will be firing at your attackers (and do the same for you).
Attackers are moving and so have a harder time identifying who is friend vs foe. Defenders know what is supposed to be there - if they see something unexpected they know it is the enemy.
That said the difference is a rule of thumb - but not a law of any sort. Well trained attackers with a good plan can greatly reduce the ratio. Defenders who don't take advantage of all their advantages also lower the ratio.
defensive missiles need to very fast and more maneuverable than attacking missiles, or the attacking missiles simply fly around them.
the fastest-accelerating vehicle ever built was a nuclear missile for intercepting nuclear missiles. they gave up https://en.wikipedia.org/wiki/Sprint_(missile)
It's almost always the case that you'll expend more than one interceptor per incoming missile as interception is probabilistic. In general, you can estimate the number of missiles you'll need to achieve a certain probability of interception with the following formula: 1 - (1.0 - sspk)^n, where sspk is the single shot probability of kill (i.e., successful interception with a single interceptor) and n is the number of interceptors.
Shameless plug here, but I wrote up a post about this problem: https://smu160.github.io/posts/missile-defense-is-np-complet...
Harder to shoot an incoming bullet than it is to fire that bullet in the first place.
With humans the math is reversed, being the defender is an advantage. Defenses can be setup pre-emptively and cheaply. Taking out a swarm of 20 Shahed drones is difficult and takes several missile batteries. Taking out a swarm of 20 infantrymen attacking a dug in position is light work for a matching force.
Shahed type drones are killed with APKWS missiles. A single fighter jet can carry ~40 of these missiles and the unit cost is similar to a Shahed. APKWS has evolved a lot during its 15 years in use and the new generations are expected to come in around ~$10k each, cheaper than the drones they are designed to destroy. You can put an APKWS on many different things. The US annual production rate is 35,000 but that could be increased several-fold if needed (it is based on a missile of which the US produces 200,000 per year). The Europeans are working on their own version of this.
These have been used in the Middle East for a long time. Saudi Arabia, UAE, Qatar, and Israel all have orders for 10,000+ APKWS missiles each, so clearly they are effective.
The unit cost has been tipping toward the defender but the systems are not widely distributed yet. More effective defenses require more expensive drones e.g. you can't build an effective anti-ship missile (a type of jet-powered drone) for less than a couple million dollars because anything cheaper has too low of a probability of success.
That said: how many APKWS missiles does it take to eliminate a full wave of Shaheds? If the answer is not 1:1 shot to kill ratio (it isn't), the match still works out in favor of the drones. If a single drone gets through it works out massively. If my defense platform is an F-15 or F-35 for cheap missiles, I also have to eat the cost and readiness loss of operating that jet ($30k per hour). We see this exact math in incidents like the Prince Sulatan Air Base attack which was defended by patriots, and where several planes were damaged or destroyed on the ground.
Its also worth pointing out that Patriots are reportedly getting used to defend against Shaheds in the gulf and Ukraine, especially the newer generations that are faster and higher flying.
If you can get any drones through at all, it still comes out assymetrical. If you shoot 9/10 of my drones down with magically free munitions, but I blow up a refinery or take out a fighter sitting on the ground I still win. Right now there just isn't a system that can guarantee 100% intercept rates over the long run.
Ukraine, Russia and Iran have all proved that there is no foolproof interceptor. Right now, the drone gets through.
Infantry troops still operate in 3D as they can/will direct mortars, air assets, etc.
In general, what you laid out is a bit of an apples and oranges comparison. An infantry platoon applies fire and maneuver using all of its elements to "close with and destroy" a smaller element.
You emplace your weapons squad which has machine guns and other large weapons (e.g., mortars) that will keep your enemy's heads down. This allows your maneuver elements (i.e., assault squads) to maneuver to the enemy force.
In the case of missile defense, you have a limited set of complex and expensive bullets, and your enemy has cheap bullets. If you want to defend yourself, you're attempting to hit your opposition's bullets with your own bullets.
OTOH, if the attacker wants a specific objective (control infrastructure, seize a resource, gain political power), that equation changes a ton in favor of the defender.
Lots of modern military strategy seems to be occupied with finding the appropriate balance between those tactics.
An example is the https://en.wikipedia.org/wiki/Battle_of_the_Shangani where 5 guns defeated a force of 7000.
However when both sides had the same capabilities, attack became very costly.
The point is, depending on the type of drone, the sheer cost of fighting them off is prohibitive with current interceptor tech (ie anti air missles). In fairness they were designed to attack targets 10x their cost, and take years to build.
For the USA specifically, they have a bunch of bases within range of cheap drones. This means that you need radar/sensor controlled chain guns, or moveable nets to defend cheaply. Its almost time for barrage baloons.