Polar-Sitter Mission for Continuous Observation of the Poles.

The Polar Sitter mission provides a continuous observation of one of the Earth poles throughout the year. In order to perform this mission, equilibrium points of the circular restricted 3-body problem with radiation pressure have been chosen as candidate positions for the satellite. The tilt of the earth spin axis with respect to the ecliptic plane 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, by studying the equilibrium points obtained with the use of solar sail propulsion, a minimization of the angle-of-sight is possible, providing a significant improvement in the geometry. .