import com.greensock.TweenLite; // get tweenlite at http://www.greensock.com/tweenlite/
var rotationValue;
addEventListener(Event.ENTER_FRAME,doOrbit)
function doOrbit(e){
rotationValue = (mouseX + stage.stageWidth / 2) * 0.5;
TweenLite.to(orbit,0.5,{rotationZ:rotationValue}); //had to use Z axis rotation (basically the same thing)
for(var i=0; i<orbit.numChildren; i++){
var planet = orbit.getChildAt(i);
TweenLite.to(planet,0.5,{rotationZ:rotationValue*-1});
}
}