  We consider the spatial central force problem with a real analytic potential.
We prove that for all analytic potentials, but the Keplerian and the Harmonic
ones, the Hamiltonian fulfills a nondegeneracy property needed for the
applicability of Nekhoroshev's theorem. We deduce stability of the actions over
exponentially long times when the system is subject to arbitrary analytic
perturbation. The case where the central system is put in interaction with a
slow system is also studied and stability over exponentially long time is
proved.
