Solar sailcraft motion in sun-earth-moon space with application to lunar transfer from geosynchronous orbit

Abstract

A three dimensional model of the dynamics of a solar sailcraft in the earth-sun-moon system is developed. The model includes the following features: (1) a development of the physics of radiation pressure; (2) the derivation of a unit vector describing the direction of the resultant radiation pressure force for two types of sails; (3) the derivation of equations of motion for the sailcraft and the moon in spherical coordinates; (4) the derivation of generalized equations for the initial conditions of the sailcraft in terms of orbit parameters; (5) the development of attitude control equations for the sail; (6) an analytical criterion to account for the periodic eclipsing of the sun by the earth, and (7) an analysis of reflection of solar radiation by planetary bodies. A computer program based on the above model and including a search routine is developed and described. The program is used, together with a search strategy for searching through a four dimensional parametric space of initial orbit parameters, to investigate the problems of transfer to the moon (impact or close flybys) from a geosynchronous orbit. Results are obtained for three types of lunar encounters and three values of the sailcraft's area to mass ratio. Results are presented for the orbits of the sailcraft and the moon for the lunar encounter and the post encounter sailcraft trajectories when applicable. It is found that a lunar impact or close flyby can take place in 63 to 67 days for an area to mass ratio of 100 and that the type of lunar encounter can result in significantly different post encounter sailcraft trajectories.