Dynamical properties of the Molniya satellite constellation: long-term evolution of orbital eccentricity

TL;DR

This paper investigates the long-term orbital eccentricity evolution of the Molniya satellite constellation using a combined mathematical model and observational data, highlighting the significance of lunisolar effects and chaos in orbital dynamics.

Contribution

It introduces a doubly-averaged dynamical model that accurately predicts eccentricity evolution and analyzes the impact of lunisolar perturbations and chaos on Molniya satellites.

Findings

Second-order expansion models eccentricity well

Lunisolar effects influence orbital elements significantly

Chaos affects long-term orbital evolution

Abstract

The aim of this work is to analyze the orbital evolution of the mean eccentricity given by the Two-Line Elements (TLE) set of the Molniya satellites constellation. The approach is bottom-up, aiming at a synergy between the observed dynamics and the mathematical modeling. Being the focus the long-term evolution of the eccentricity, the dynamical model adopted is a doubly-averaged formulation of the third-body perturbation due to Sun and Moon, coupled with the oblateness effect on the orientation of the satellite. The numerical evolution of the eccentricity, obtained by a two-degree-of-freedom model assuming different orders in the series expansion of the third-body effect, is compared against the mean evolution given by the TLE. The results show that, despite being highly elliptical orbits, the second order expansion catches extremely well the behavior. Also, the lunisolar effect turns out to be non-negligible for the behavior of the longitude of the ascending node and the argument of pericenter. The role of chaos in the timespan considered is also addressed. Finally, a frequency series analysis is proposed to show the main contributions that can be detected from the observational data.