Cool, is that sketch up pro?
Back when it was free I did a very similar model to illustrate the 'hazard zone' of a laser for the FAA... a volume of airspace the laser could point to (all possible angles where the moon could be over the course of a year) where the laser intensity was over a limiting value. It took a very long time to do.
I never knew you could do the terrain overlay... how hard was that in sketch up?