We consider a Hamiltonian system modeling the plane restricted
elliptic 3 body problem with one of the masses small and prove the
existence of periodic and chaotic orbits shadowing chains of
collision orbits. Periodic orbits of this type were first studied
by Poincaré for the non-restricted 3 body problem. The present
paper contains general results which hold for time periodic
Hamiltonian systems with a small Newtonian singularity.
Applications to celestial mechanics will be given in a subsequent