Planning for Exhaustion: Massed Drones and the Magazine-Depth Problem

Most counter-drone systems fielded over the past decade share an implicit design assumption: one target at a time. The operator's display, the engagement sequence, the rules of engagement, the after-action assessment — the entire architecture of defensive fire presumes a raid of one, perhaps a few. Massed drone attacks break the assumption rather than the hardware, and they do it arithmetically. A defense's capacity against a raid is the product of two numbers: engagement rate, how many targets it can prosecute per minute given its sensors, fire-control channels, and effector fly-out times; and magazine depth, how many engagements it can sustain before reload. The saturation attacker does not need to defeat either number. He needs only to exceed their product, and with airframes costing a few thousand to tens of thousands of dollars, exceeding it is a procurement decision, not a technical feat.

The operational evidence has been accumulating for years. One-way attack drones in the Shahed class have been employed in waves sized and timed to stress air defenses — arriving on multiple axes, at low altitude, in numbers calculated against the defender's known magazine. The tactical purpose is often exhaustion itself: force the defender to expend interceptors, reveal emitter and launcher positions, and degrade coverage for the cruise missiles and ballistic weapons that follow. Ukrainian air-defense practice, and the Western resupply problem it created, made the arithmetic public — interceptor stocks costing orders of magnitude more per shot than the drones they killed, drawn down at rates no production line could sustain. The lesson generalized quickly: any defense priced for exquisite targets will be bankrupted by cheap ones, and the bankruptcy is a strategy the attacker can plan around.

The cost-exchange problem reframes what a good counter-drone weapon is. A defense that kills a twenty-thousand-dollar drone with a four-hundred-thousand-dollar missile wins every engagement and loses the campaign. The metric that matters is cost per raid defeated, not cost per kill, and optimizing for it produces a different force. The first response is cheap effectors in quantity: laser-guided 70-millimeter rockets in the APKWS class, which convert unguided rocket stocks into precision counter-drone weapons at a per-shot cost in the low tens of thousands of dollars, now employed from ground launchers and aircraft; the Coyote interceptor family, selected by the US Army's joint counter-drone architecture and ordered in quantity precisely because it trades interceptor sophistication for magazine depth; gun layers with deep ammunition stocks; and interceptor drones cheap enough to expend freely. Each accepts shorter range or lower certainty per shot in exchange for shots the defense can afford to repeat.