Satellite Orbital Drag During Extreme Geomagnetic Storms: How Accurate are our Predictions?

Abstract:

Satellites orbiting Earth at the upper atmosphere (~400 km altitude), known as low-Earth orbit satellites, are exposed to drag forces which directly cause their orbital decay. Satellite orbital drag corresponds to a key factor in space weather investigations because it directly affects the satellite tracking and orbit predictions. During geomagnetic storms, thermospheric neutral particles/molecules are heated by intensified ionospheric currents and upwell to regions where fewer neutral particles are found during quiet times. The increased density in turn enhances the satellite orbital drag, anticipating the end of its life time. Recent results show that this heating can propagate in the thermosphere from auroral zones toward the equator within 3 hours after the onset of storm main phases. The main goal of this presentation is to inform the community on new findings concerning extreme geomagnetic storms, i.e., minimum SYM-H < -250 nT, and their implications to subsequent satellite orbital drag computations. A recently developed technique combining modeling and experimental approaches will be presented, and a discussion on the next steps towards the improvement of satellite orbital drag predictions will be undertaken.