On the attitude control by thruster of a spinning solar sail and bending moment's effect analysis

The membrane dynamics of spinning solar sails have a special relevance when considering attitude control of the spacecraft. So as to model the system accurately, the bending stiffness of the membrane has been included in the numerical approach, as it is believed to have strong effects on the behavior of the sail. First, this study shows that the influence of the bending moment on the attitude of the sail during its spin axis reorientation should not be neglected. Given the difficulty of measuring the actual bending stiffness of the membrane, finding a control system capable to perform the same regardless of its value is necessary. Therefore, this paper presents a new control system and its corresponding logic to lower the influence of the bending parameter on this attitude maneuver performance. Finally, a frequency analysis on the vibrations arising in the membrane when considering different bending stiffness values is done. This last analysis shows the shift in the natural frequencies obtained, remarking the importance of the bending stiffness when considering the dynamics of a mast-free sail.