[pmulcahy11b]

Another thing various countries have been working on for years is high-acceleration heat-seeking missiles designed to take down other missiles, like SAMs. The problem is that the seeker has to be really, really sensitive to pick up the rocket exhaust from any angle, since the SAM isn't in flight long enough to develop much heat along its body, and then pick up the heat from the rocket after it shuts off, since most SAMs are powered for only 1-4 seconds of flight and then coast the rest of the way.