On the dominant lunisolar perturbations for long-term eccentricity variation: the case of Molniya satellite orbits

The aim of this work is to investigate the main dominant terms of lunisolar perturbations, that affect the orbital eccentricity of a Molniya satellite in the long term. From a practical point of view, these variations are important in the context of the space situational awareness, for instance to model the long-term evolution of an artificial debris in a highly elliptical orbit or to design a reentry end-of-life strategy for a satellite in a highly elliptical orbit. The study assumes a doubly-averaged model including the Earth's oblateness effect and the lunisolar perturbations up to the third-order expansion. The work presents three important novelties with respect to the literature. First, the perturbing terms are ranked according to their amplitudes and periods. Second, the perturbing bodies are not assumed to move on circular orbits. Third, the lunisolar effect on the precession of the argument of pericenter is analyzed and discussed. As example of theoretical application, we depict the phase space description associated with each dominant term, taken as isolated, and we show which terms can apply to the relevant dynamics in the same region.