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.

energy123 11 hours ago | parent [-]

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).

	▲	hedora 10 hours ago \| parent \| next [-]
		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.
	▲	adampunk 11 hours ago \| parent \| prev [-]
		Well there the cost plays a part! It’s not independent. If I can build 1000 missiles for every 1 interceptor, the probability of interception hardly matters. This actually was why we planned to put lasers in space: the economics of one nuclear-pumped laser reflected through Unobtanium were better than any other interceptor. And even that if the effect worked (it didn’t, they could not prove lasing and fired an engineer who blew the whistle on that), the system could be defeated by a staggered salvo.