Thrust vector direction and magnitude determination of a solar sail spacecraft with thin-film reflectivity control devices

The paper is devoted to the model of the photon reflection from the nonperfectly reflecting surface of the solar sail. The model is designed to determine the direction and magnitude of the thrust vector of a solar sail spacecraft, which are necessary during interplanetary flights. Such types of photon reflection as specular reflection, diffuse scattering, absorption and transmission are considered. Due to degradation, surface variance, changes in the solar sail shape during the flight, diffuse scattering and radiation from heating the surface of the solar sail occur random. Thus, the problem of determining the total thrust vector arises. The paper proposes to use a number of assumptions that eliminate this problem. A comparison of the results obtained using the new model for determining the direction and magnitude of the total thrust vector and experimental data is carried out. It was revealed that the maximum relative error is 2.3%. The developed model was adapted for a solar sail equipped with thin-film reflectivity control devices.