Long-Term evolution of geosynchronous orbital debris with high area-to-mass ratios

The long-term evolution, over 54 years, of a sample of objects released in geostationary orbit with area-to-mass ratios (A/M) up to 50 m2/kg was analyzed, taking into account geopotential harmonics (8 x 8), luni-solar perturbations, direct solar radiation pressure with eclipses and, when applicable, air drag. The results obtained indicate that objects with A/M in between 10 and 25 m2/kg, depending on the release initial conditions and elapsed time, might explain the recently discovered debris population with mean motions of about one revolution per day and orbital eccentricities as high as 0.55. At so large area-to-mass ratios, the orbital evolution was mainly driven by solar radiation pressure. Even though the general behavior observed was the same in all studied cases, the detailed evolution depended on the initial conditions and the angle between the Sun and the eccentricity vector. The simulated objects with A/M < 15 m2/kg were characterized by an orbital lifetime > 54 years, and the same was often the case for 17-20 < A/M < 36-39 m2/kg. However, an 'island' of relative instability was found for 16-17 < A/M < 25-26 m2/kg, while for A/M > 30-40 m2/kg, again depending on the initial conditions, the lifetime dropped rapidly to a few months with increasing values of A/M.