Effect of Equinoctial Precession on Geosynchronous Earth Satellites

Abstract

The long-periodic effects of the equinoctial precession on geosynchronous Earth orbit satellites are investigated. The equations of motion in a reference frame that coprecesses with the Earth are developed, and the resulting variational equations are derived using mean classical orbital elements. The Earth gravitational model includes the J 2 and J 3 zonal harmonics, which induce the equinoctial precession due to the lunisolar gravitational torque. It is shown that the ever-growing lifetime and mass of geosynchronous Earth orbit satellites render the equinoctial precession a significant factor, which should be taken into account during mission design, as it affects north-south stationkeeping maneuvers. The equilibria of the variational equations including the zonal harmonics and the equinoctial precession are investigated and a class of stable frozen orbits which are equinoctial precession invariant is derived.