Computations of the Shape of the Rotor-Type Solar Sail

Consideration is given to a problem that appears in the investigation of operational processes of a spacecraft with a rotor-type solar sail composed of 16 blades fabricated from the fine film. The shape of such a freely deformable construction is sustained by centrifugal forces arising from the rotation of the sail about its axis of symmetry. A computational procedure has been devised to determine the equilibrium configuration of the solar sail in the course of its steady rotation. The procedure is based upon the special techniques that enable the equilibrium shape of the film to be approximated by triangulated polyhedron. Such an approximation is intended to be used in an application package for computing light pressure force and torque acting on the sail. The question of building an approximation has been approached from two angles. The first approach to be described is based upon the finite-element method, so called Courant's triangles being used. Within the context of the second one the surface of the sail is thought of as a set of massive balls joined by weightless threads or springs. The close agreement of the two approximation techniques has been shown. The results of the sail's shape computations performed according to the second technique are diagrammatically presented.