From a coding point of view, the collision detection and deleting the instances upon collision and issuing a message of success wouldn't be too much of a problem. The complexity is in the algorithm, which brings up an interesting idea... and Urwumpe, perhaps you can work this in to your existing design:
It would be nice to have a generic missile coded with the collision detection, etc, however have the algorithm programmable by the user. This would allow for a variety of ideas. For one, peeps can test out different ideas and concepts, and furthermore we could have a bit of a competition, using a variety of scenarios to test out and compare/evaluate each one.
The algorithm could be read in using some form of parser, given certain variables for the user to work with, i.e. various vectors to the target, etc, which then drives a vector change for the rocket/missile.
Just a thought...
Vangaurd