Low-Eccentricity Elliptic Orbits in a Central Force Field with Drag

Abstract

This paper studies low-eccentricity elliptic orbits of satellites in the gravitational field of a spherical body or in the equatorial plane of an oblate body subject to the influence of quadratic drag. Approximate analytic expressions for these orbits are presented for different models of the atmospheric density. The orbits computed from these analytic expressions are compared with those obtained from the numerical integration of the exact equations of motion with the same atmospheric model. For low-eccentricity orbits the deviation between the analytic and numerical orbits after ten revolutions is less than 5 m. These results generalize similar analytical expressions that were derived recently for nearly-circular orbits.