Trajectory Approximation of a Solar Sail with Constant Pitch Angle and Optical Degradation

The aim of this article is to analyze the 2-D heliocentric trajectory of a solar sail with constant attitude in the presence of reflective film optical degradation. The proposed procedure starts from the results obtained for a nondegrading flat sail, and taking into account the film optical degradation, obtains an analytical (although approximate) form of both the polar trajectory and the osculating orbit characteristics. In this context, the solar sail state vector is modeled through a set of nonsingular elements, and the heliocentric dynamics is analyzed with the aid of the perturbation theory, where the propulsive acceleration represents the (small) perturbative term. The soundness of the mathematical model is discussed for a propulsion system whose performance is consistent with the current solar sail technology.