Orbit simulator

I mentioned this to Kevin a short time ago, and just found a link:
 

 

http://www.colorado.edu/physics/2000/applets/satellites.html

 

If you click, move the mouse, and release, you can launch a satellite.

 

I've seen other versions of this where you can do it without the moon.

 

I find it difficult or impossible to get a stable orbit unless I make the satellite go the opposite way the moon goes.