Spin-stabilized solar sail for displaced solar orbits

An optical force model is used to investigate the stability of a flat spinning solar sail in a displaced solar orbit. The solar sail can be stabilized in the orbit by design of the spinning rate and the sail structure. The orbital and attitude dynamics are studied separately. The orbit is stable as the sail attitude keeps fixed with respect to the sunlight, as does that of a perfectly reflecting solar sail. The attitude is stable as long as the spin angular velocity is much larger than the orbital angular velocity. The stability of the individual components cannot guarantee the stability of the entire system since the orbit and attitude interact with each other. Therefore, the coupled dynamics of the orbit and attitude are used to study the overall stability; the results show that the coupled system is also stable. It should be noted that the orbit and attitude are critically not asymptotically stable. The analysis only provides the necessary conditions for stability because a linearization is performed. To numerically verify the nonlinear stability of the true nonlinear system, the dynamical equations are simulated for a time that is longer than the mission life.