Moon Sitter mission for observation of the lunar poles

The Moon Sitter Mission provides a continuous observation of one of the Moon poles. Solar sails can produce equilibrium solutions which can be used so as to accomplish the Moon Sitter mission. In order to perform this mission the dynamics of the Earth-Moon system are investigated when a solar sail spacecraft is considered. Equilibrium points of the circular restricted three-body problem with radiation pressure have been chosen as candidate positions for the satellite. Equilibrium positions which are solutions of the restricted three-body problem of an Earth-Moon-sailcraft system can be exploited so as to observe high latitude regions of the Moon. For the Earth-Moon system, the radiation pressure force is not due to one of the primary masses but to the presence of the Sun, therefore in order to include the photonic force in the equation of motion the dynamics of this three-body system are no longer autonomous as the Sun line rotates once per synodic month w.r.t. the Earth-Moon co-rotating reference frame. The relative position between Moon and Sun, prevents the sailcraft from keeping a constant equilibrium location over the poles, thus causing increasing values of the angle-of-sight between the satellite position and the north pole. In this paper we show that a minimisation of the angle-of-sight is possible, with significant improvement in the orbit geometry. The satellite performance is expressed in terms of the angle-of-sight and of the distance of the sailcraft from the Moon pole, while the position of the Sun changes.