>It is within the performance envelope of those types of systems.
Is this true? Reentry speed of an ICBM is something like 5 km/s. Entry speed of a meteor is a minimum of 11 km/s, and more like 25 km/s if this object wasn't in an Earth-like orbit to begin with. Missile interceptors travel much slower than either, and they have a tough time hitting ICBMs from what I understand.