Flexible heliogyro solar sail under solar radiation pressure and gravitational force

This study proposes a formulation for the dynamics of a flexible multibody heliogyro solar sail undergoing rigid body motion and multi-blade vibration. The heliogyro solar sail consists of a rigid central hub and flexible solar multi-blades. The floating frame approach is applied to describe large translational and rotational motions, as well as blade deformations, including the flap, lag, and twist modes. First, the solarelastic instability induced by Solar radiation pressure (SRP) is revisited in the linear stability and nonlinear transient analysis. Then, the gravity-induced instability on the heliogyro solar sail is proposed, and the 1st flap mode is shown to become divergent under gravitational force. Strain energy variation is applied to determine the contribution of the divergent behavior after the onset of the instability. Finally, suitable operational spin speed and altitude in the Sun-synchronized Earth-centered orbit are proposed for the stabilized flexible heliogyro solar sail mission.