Semi-analytical attitude propagation of low-altitude Earth orbiting objects

The paper introduces an averaged model suitable for studying the long-term attitude dynamics of low Earth orbit objects subject to the interaction with the exosphere. This work extends previous results by the authors on the development of a semi-analytical theory for long-term attitude propagation. The first-order averaged model is developed by expressing the rotational problem in modified Sadov variables and performing the average of the equations of motion over the fast Sadov angles and the orbital mean anomaly. A transformation from osculating to mean variables is also derived from a combination of Lie transformations. The approach proposed in this paper is applied to two possible atmospheric drag models: a simple, commonly used, model characterised by a constant dimensionless drag coefficient and a higher fidelity model based on the theory by Sentman (1961).