Binding energy of a satellite is the energy which must be added to planet-satellite system to free the duo from their gravitational attraction.
If a satellite of mass
We know that for circular motion
and force of gravity is
As the system is in equilibrium, the centripetal force must be balanced by the gravitational attraction force between the two. Therefore we get
Inserting this value in (1) we get
When the planet-satellite duo are free from each others gravitational pull, (implies that
Using (3) we have