Analysis of high area-to-mass ratio (HAMR) GEO space object orbit determination and prediction performance: Initial strategies to recover and predict HAMR GEO trajectories with no a priori information

Optical deep space surveys are focusing on the study of a class of near Geosynchronous (GEO) objects characterized by high area-to-mass ratio (HAMR). Consistent cataloging and study of these HAMR objects requires repeated follow-up and tracking. The combination of lunar–solar gravitation, unmodeled solar radiation pressure dynamics, thermal emissions, and possibly passive electrostatic charging of the object interacting with the weak magnetic field at GEO results in unknown perturbations to the its trajectory. When these effects are combined with their apparent dim, time-varying reflective light intensity magnitudes, correctly identifying/associating tracks to the HAMR object is non-trivial. The focus of this work is to quantify the effects of the unmodeled accelerations on the reconstructed and predicted HAMR trajectory. Optical angle tracking data for several candidate HAMR objects were reduced and analyzed, and compared with results derived from the reduction of simulated optical angles data generated from the same sites, over comparable durations and using known dynamical models. Comparison of the orbit determination results provides insight into the effects of unmodeled errors on the estimated orbit parameters and their associated uncertainties. The results conclude that the orbit errors resulting from unmodeled rotational dynamics are significant, and can require the addition of process noise to properly account for the force model uncertainties to the total state error distribution. The results further demonstrate that the longer term solar radiation pressure effects are well determined with adequate observations, but determination of shorter term variations due to rotational dynamics are dependent on the area-to-mass ratio, measurement quality and estimation sampling interval.