Kinematic orbits and their usage in determining space weather storms induced orbit decays

Low earth orbiting (LEO) satellites can be affected by space weather events like coronal mass ejections (CMEs) in such a way that the drag force acting on the spacecraft is enhanced due to increasing atmospheric neutral density. As a consequence, this leads to an additional storm induced orbit decay. LEO satellites equipped with accelerometers offer the possibility to deduce information on the current state of the atmospheric neutral mass density based on the measurements of non-gravitational forces acting on the spacecraft. However, satellites with suitable onboard accelerometers are extremely rare. An alternative method to derive atmospheric densities along a satellite trajectory can be realized through the usage of global navigation satellite system (GNSS) based kinematic orbit information. This approach offers the advantage that that theoretically almost every LEO satellite mission which is tracked by GNSS can be used for the evaluation. In addition, through the increasing number of analysable satellites the explorable altitude range can be expanded to 300 km - 800 km. Thus, a tomography of the upper Earth’s atmosphere is feasible and the impact of a solar event on a satellite can be estimated as a function of its orbital altitude. In this study, we present density estimates based on kinematic orbits during quiet and active solar periods. The results are compared to state-of-the-art thermosphere models like the NRLMSIS 2.0, JB2008 and HASDM. In the case of extreme solar events the investigations are extended by estimating the storm induced orbit decay for different altitudes and satellites.