Is it technologically feasible to shoot down a North Korean rocket/ ICBM?
If you have a system that works 10% of the time it’s pretty much the same as having no system. If you have a system that’s 50% effective, then the easiest thing for your opponent to do is to double production of their weapons. In order for a system to be a net win, you would need it to be very effective, especially in this case. North Korea isn’t going to be fighting an extended nuclear duel with the United States. All they have to do is threaten to destroy one city in Japan or the United States. For that you don’t need certainty. You just need a better than even chance of success. North Korea knows that if they actually attack the United States, they would end up a heap of glowing rubble. The missiles and nukes are not being built for war fighting. They’re being built to prevent an invasion, to extort money and food from the rest of the world, and to sell on to other countries. Analogously, anti-missile systems aren’t being pushed because they work. They’re being pushed as a way to fe
The ship based SM-3 and land based Patriots in Japan are intended as area defense weapons, defending a relatively small circular area around the weapon; e.g., a ship or city. If the bad-guy missile is headed toward a defended area then there is a reasonable chance, with a little luck, that it can be shot down. If the missile is headed over the Sea of Japan, and over Japan, then there is not much that can be done. If the N. Korean launch site is near the coast then conceivably a relatively nearby Aegis ship could do something in the early moments of flight before the missile gathers much speed; don’t know if that’s conceivable for lots of reasons. Likewise, in theory, we could have some hovering aircraft – manned or unmanned – with air to air missiles ready to wack the missile right after launch. Obvious political problem there since we presumably would have to violate their airspace to accomplish this. Moreover, any launch phase intercept would have to be conducted preemptively before
Japan has deployed a battery of patriot missile interceptors, in case the “satellite” encroaches on / falls into Japanese airspace. To prepare for any dangers caused by a failed launch, batteries of PAC-3 land-to-air missile interceptors were sent to Akita and Iwate, the two prefectures that the rocket is expected to fly over, the Defense Ministry official said, adding that preparations to defend the area around Tokyo from falling debris are already complete. Best guess is that nobody will attack the missile while it’s on the ground or in early boost- that would violate NK’s territory and probably lead to an escalation. If it appears to threaten Japan, then the patriots will hopefully be able to protect the folks who live up north from any missile parts.
There are three phases of flight in which you can try to intercept an ICBM: the boost phase, when it has just launched and is burning off its fuel as fast as possible to accelerate up out of the atmosphere. Current US/Japan ship-based Aegis BMD anti-missile systems are not designed for boost-phase intercept; the current generation of 13″-diameter SM-3 missiles burn out around 3 km/s which is not fast enough to get to even a relatively slow liquid-propellant ICBM rising from inland North Korea during the 5 or so minutes it is burning, even if you assume immediate acquisition, identification, decision, and solution. (We’re working on a faster 21″ SM-3 but it is not yet deployed.) mid-flight, when it is has shed its boosters and is just a giant nuclear lawn dart arcing through the vacuum of space. Japan successfully intercepted a test missile at 100+ miles high with an Aegis+SM-3 system a year or so ago, so this is theoretically possible — but they knew pretty well where that missile woul
