Neville, I have attached a Power Point show that demonstrates a geo-satellite concept..(i did not check the geo-sat figures for altitude I only looked at the animation) but PP is crude and limited in its ability to show detail like relative speeds and elliptical orbits and the nessisary transfer orbits ...I thought i would send this as a rough example and suggest that maybe this kinda animation be incorporated into GU 4.0 or somewhere since explaining geo-sats in a geo- universe is difficult for many to visualize without a good diagram or animation i think..just a suggestion i think could /would be useful..... this was put to gether by my dad i have been showing him how to "play" PP but he is wanting somthing to use in his classes and i suggested to let you take a look at it and see if you wanted to do a better & or more fluid/ accurate animation at some point maybe in GU 4.0 ....but all in all he is having alot fun with it now....:)