INTEGRATION OF COUPLED ORBIT AND ATTITUDE DYNAMICS AND IMPACT ON ORBITAL EVOLUTION OF SPACE DEBRIS

This paper deals with the integration of coupled orbit and attitude dynamics over the long term for uncontrolled space objects. In the objective of space debris mitigation, orbital propagation is required to evaluate the evolution of orbital elements over long time scales up to more than 100 years. In many cases, the hypothesis of "cannonball model" is applied. Assuming a randomly averaged attitude, it enables to perform orbit propagation, uncoupled from the attitude motion. Yet, modelling the attitude dynamics and evaluating attitude dependent forces may be needed to obtain a more representative orbit evolution. The aim of this paper is two-fold: first, analyzing the coupled orbit and attitude propagation for a low area-to-mass ratio in Low Earth Orbits and compare the induced orbital evolution with uncoupled propagation; second, investigating the efficiency of integration techniques. Based on 6-Degrees-of-Freedom (6-DoF, position and attitude) numerical simulations, this paper highlights the strong sensitivity of the attitude dynamics to initial conditions. The chaoticity of the coupled system is analyzed and some situations of temporary stable attitudes are shown. Then, the impact of the coupling is studied in terms of orbital evolution and lifetime. Finally, an Encke-type correction algorithm is applied for the coupled numerical integration, paving the way for improved computational efficiency.