How to adjust movement speed along a path (follow path) ?

Hello

I have used “Follow path” restriction to make a volleyball orbit the Earth.
However it does not look realistic because when its closer to the camera it should go faster.
The ball moves with constant speed along the curve. I want to change that.

I tried the DopeSheet editor but it does not give me markers for the path or curve objects.
Perhaps I am doing something wrong, perhaps there is some other way… ?

How to ?

Thanks in advance
Dimitris

In graph editor select the path evaluation time channel, press N to show its properties and delete the modifier. Now you can manually control the speed.
Instead just use the Follow Path constraint, enable ‘Fixed Position’ and keyframe the Offset value
http://wiki.blender.org/index.php/Doc:2.6/Manual/Constraints/Relationship/Follow_Path

Please ALWAYS for support question attach or link to your blend file