Trajectory behavior of high area-to-mass ratio objects in semi-synchronous GPS orbits

Following the observational discovery of a significant number of objects characterized both by high eccentricity geosynchronous orbits and by extremely high values of their area-to-mass ratios (A/M), whose origin can probably be traced back to the degradation and detachment of the very light specific mass layers used to protect the surfaces of geostationary spacecraft, a thorough investigation was carried out since 2008 to explore the long-term dynamical evolution of fictitious high A/M objects released, with a negligible Delta-V, in each of the six orbital planes used by Global Positioning System (GPS) satellites. As for the objects observed and studied in near synchronous trajectories, also in this case long lifetime orbits, with mean motions of about 2 revolutions per day, were found possible even for bodies with extremely high A/M. The behavior details, affected by the complex interplay of solar radiation pressure, geopotential and luni-solar resonances, obviously depend on the initial conditions. However, objects with A/M as high as 20-40 m2/kg can avoid orbital decay for at least one century or more, with semi-major axes close to the semi-synchronous values, with maximum eccentricities between 0.3 and 0.7, and with significant orbit pole precessions (faster and wider for increasing values of A/M), leading to inclinations between 30° and more than 90°. For particularly high values of A/M, in fact, the transition from prograde (inclination < 90°) to retrograde (inclination > 90°) motion, and vice versa, would be possible.