High-precision numerical calculation method of solar radiation pressure force for wrinkled solar sails

Due to small magnitude of solar radiation pressure (SRP), the area-mass ratio of the solar sail should be large enough to obtain adequate thrust acceleration. Therefore, the membrane structure is usually adopted for solar sails. However, the membrane barely has out-of-plane stiffness; thus, it is necessary to apply in-plane tension on the membrane for maintaining the plane, which may result in wrinkles. The wrinkle will influence SRP force of solar sails. On the one hand, wrinkled regions of the sail are no longer flat, so the angle between the normal vector of the surface in wrinkled regions and the direction of sunlight differ from a flat sail. On the other hand, wrinkles may cause shadow when the solar sail is almost parallel to sunlight and the shadow region cannot generate SRP force. In this paper, the nonlinear buckling theory is used to propose a numerical calculation method to solve the problem of wrinkling analysis of solar sails with complex boundary. Then, a high-precision method for calculating SRP force of wrinkled solar sails is proposed, consisting of two parts: the infinitesimal element SRP force model and the wrinkle shading model. Numerical simulation result verifies the effectiveness of the wrinkling analysis method and the SRP force calculation method. Furthermore, according to calculation result, wrinkles have a certain influence on the SRP force of the solar sail, which will become significant when the solar sail gets parallel to sunlight.