TITLE: Station keeping of a Solar sail around a Halo orbit AUTHORS: Ariadna Farres Institut de Mecanique Celeste et de Calcul des Ephemerides Observatire de Paris 77 Avenue Denfert-Rochereau, 75014 Paris, France Angel Jorba Departament de Matematica Aplicada i Analisi Universitat de Barcelona Gran Via 585, 08007 Barcelona, Spain ABSTRACT: Solar sails are a concept of spacecraft propulsion that takes advantage of solar radiation pressure to propel a spacecraft. Although the thrust provided by a solar sail is small it is constant and unlimited. This offers the chance to deal with novel mission concept. In this work we want to discuss the controllability of a spacecraft around a Halo orbit by means of a solar sail. We will describe the natural dynamics for a solar sail around a Halo orbit. By natural dynamics we mean the behaviour of the trajectory of a solar sail when no control on the sail orientation is applied. We will then discuss how a sequence of changes on the sail orientation will affects the sail's trajectory, and we will use this information to derive efficient station keeping strategies. Finally we will check the robustness of these strategies including different sources of errors in our simulations.