  We propose a Nonlinear Model Predictive Control approach to spacecraft
rendezvous in non-Keplerian Lunar orbits. The approach is based on the
Pontryagin Minimum Principle and allows the accomplishment of
minimum-propellant maneuvers. The relative motion between the chaser and the
target is described by the nonlinear and unstable dynamics of the circular
restricted three body-problem. In the proposed formulation, we design a
minimum-propellant controller, which leads to a bang-bang behavior of the
control signal. Under suitable assumptions, simplified dynamics is employed as
prediction model, in order to reduce the complexity of the controller algorithm
but, at the same time, without penalizing the controller tracking performance.
The proposed approach's effectiveness is validated by a simulation example.
