You guys are riot (Alex and Gareth)! :>)

I'm sure there are folks much smarter than I who are considering the exact problems you have posed. Who knows, they may be exploring even more sophisticated probabilities that are not even advanced here! I'll leave it up to those guys to figure out how to make it work.

But to leave you with an encouraging thought ...the system, so far, has only been able to shoot down two out of the four missils shot at. Maybe the next attempt will fail!

DougR