Attitude Control Methodology for Large Solar Sails

摘要

In this paper, an attitude control methodology for large-size (on the order of kilometer squared) solar sails is proposed. The methodology is demonstrated for the case of a square sail divided into four equal triangular wings held together by two rigid perpendicular booms. By adjusting the position of a wing tip along the boom, the shape of the wing is altered. Under the effect of solar radiation pressure, the wing will naturally curve. This curvature in the wing will cause a change in the position of the center of pressure as well as the total solar radiation force vector acting on the wing, resulting in a torque that can be used for attitude control. This methodology exploits the sail film geometry itself to generate the necessary control forces and torques, rather than Introducing extra control elements into the system. The mathematical relationship between the displacement of the wing tip and the control torque generated is fully developed under quasi-static conditions and assuming the wing takes on the shape of a right cylindrical shell. A case study that shows the effectiveness of the proposed method for a typical large solar sail is also presented.