Long-term orbit dynamics of decommissioned geostationary satellites

In nominal mission scenarios, geostationary satellites perform end-of-life orbit maneuvers to reach suitable disposal orbits, where they do not interfere with operational satellites. This research investigates the long-term evolution of decommissioned satellite under assumption that maneuver does occur and evolves no control. The dynamical model accounts for all relevant harmonics gravity field at altitude as well solar radiation pressure third-body perturbations caused by Moon Sun. Orbit propagations are performed using two algorithms based on different equations motion numerical integration methods: (i) Gauss planetary modified equinoctial elements a Runge-Kutta scheme 8-7th-order Dorman Prince formulas; (ii) Cartesian state in an Earth-fixed frame Fehlberg 7/8 scheme. results exhibit excellent agreement over times decades. Some well-known phenomena emerge, such longitudinal drift due resonance between orbital Earth's rotation, attributable J22 term geopotential. addition, perturbation Sun causes major effects: (a) precession plane, (b) complex dynamics. study proposes analytical approach prediction precessional shows its obtained numerically. Moreover, show above mentioned dynamics persists time scales several Frequent unpredictable migrations toward longitude regions occur, contrast known effects only perturbation.