I want to add to this, we currently today can’t even reliably shoot a missile to blow up another missile in the way you’re describing, by detonating it next to the attacking missile. It’s much, much easier to calculate the incoming attack missile trajectory and fire a defense missile to slam into it head on to destroy it. If the US can’t do this with things going much slower, that are much smaller, with a controlled trajectory, and like a million times closer, there’s no way we can do it in space yet.