Estimate of the Input of Suprathermal Oxygen Atoms to the Atmospheric Drag of Low-Earth-Orbiting-Eartn-Satellites

Abstract

Suprathermal particles form in the Earth’s upper atmosphere with energies an order of magnitude greater than the average kinetic energy of surrounding gas particles. In the polar regions, the main mechanism for the formation of such particles is due to the precipitation of auroral electrons of magnetospheric origin. Intense formation of suprathermal oxygen atoms O_h during geomagnetic storms can cause additional braking of low-Earth orbiting (LEO) satellites in polar orbits due to the high accommodation of these atoms with the satellite surface. During extreme solar events, these processes can significantly reduce the accuracy of LEO satellite dynamics forecasts based on empirical upper-atmosphere models. Therefore, theoretical calculations using kinetic models are particularly relevant when analyzing such events. In this paper, we evaluate the contribution of suprathermal oxygen atoms to the atmospheric drag of LEO satellite in polar orbits during extreme geomagnetic storms. To this end, (a) the kinetics of O_h formation and transport in the upper atmosphere are calculated and (b) the motion of LEO satellite in the disturbed atmosphere is modeled. Based on calculation results, it has been established for the first time that, due to the influence of suprathermal oxygen atoms produced in large quantities during extreme geomagnetic storms, the positions of LEO satellite at altitudes of 400–800 km can deviate from those predicted by empirical models by up to 5 m in altitude and up to 350 m along the orbit. These deviations amount to 40% (for satellite with an orbital altitude of 400 km) to 300% (for orbital altitudes of approximately 800 km) of the typical errors of the predictive models. This demonstrates the need to account for suprathermal particles and utilize kinetic models to accurately predict the motion of LEO satellite during extreme solar events.