A New Model for the Planetary Radiation Pressure Acceleration for Solar Sails

Solar sailing is a propellantless propulsion method that takes advantage of solarradiation pressure to generate thrust. The last decades have seen the launch ofseveral solar-sail missions to demonstrate the technology’s potential for spaceexploration and exploitation. Even more missions are scheduled for launch inthe near future, including NASA’s ACS3 and NEA Scout missions and Gama’sAlpha sailcraft. Although most of these sailcraft have flown – or will fly – inLEO, where the planetary radiation pressure is strong (up to approximately 20%of the solar radiation pressure), studies on the perturbing accelerations producedby the Earth’s albedo and blackbody radiation have been conducted only to avery limited first-order extent. This paper therefore provides a novel, detailedanalytical model for these perturbing accelerations, valid for double-sided perfectlyreflecting solar sails. The underlying assumptions of the model are presentedand its full derivation is described. A thorough analysis of the blackbodyand albedo radiation pressure accelerations is conducted for a variety of orbitalconditions and Sun-Earth-sail configurations. In order to quantify the accuracyof the model, a comparison with the state of the art (the finite-disk radiationsource model) is provided. Ultimately, a variety of analyses to quantify the effectof Earth’s albedo and blackbody radiation on the maneuvering capabilitiesof solar sails are provided, using the orbit of the ACS3 mission as reference scenario.These analyses show that, for an orbit-raising steering law, losses in thealtitude gain of 19.6% of the total gain are incurred over a 10-day orbit-raisingperiod. Similarly, losses in the inclination gain of up to 25% of the total gain areobserved when implementing an inclination-changing steering law. These resultshighlight the non-negligible effect of uncontrolled planetary radiation pressureacceleration on the maneuvering capabilities of solar sails in LEO.Astrodynamics & Space MissionsSpace Engineerin