Long-term evolution of disposal orbits beyond the geostationary ring Original Research Article

The effect of long term gravitational influence of the Earth, Moon and Sun, together with the Sun radiation pressure was studied for a randomly generated population of 10000 orbits with the perigees taken from the interval 50–3000 km above the geostationary ring. The evolution of each orbit on a time span of 200 years was studied by means of an explicit sixth-order symplectic integrator of the Wisdom-Holman type. 389 orbits crossed the ‘security zone’ of 35 km above the geostationary orbit, most of them during the first 10 years. The simulation indicates a strong correlation between the semi-major axes and the eccentricities of ‘unsafe orbits’. Some less significant effects in the distribution of elements for such orbits are also discussed.