Exploration and Forecasting of Thermospheric Variations at Different Altitudes Within the Framework of Project SWEETS

Owing to advances in solar research in the recent decades, today we know that coronal mass ejections (CMEs) cause the most comprehensive spectrum of space weather disturbances. These huge clouds of magnetized plasma are propagating from the solar corona into interplanetary space with typical transit times that range between two and five days, depending on the initial speed, the mass, the size as well as the speed and density of the surrounding solar wind plasma. During strong geomagnetic storms, induced by CMEs, the neutral density of the Earth’s thermosphere is subject to strong fluctuations and, thus, a critical parameter for low Earth-orbiting satellites. The enhanced energy input from the solar wind to the magnetosphere causes heating and expansion of the Earth’s thermosphere, which affects Earth-orbiting satellites in such a way that the drag force acting on the spacecraft is enhanced and leads to an additional storm induced orbit decay.
Within the project SWEETS (FFG funded) it is intended to develop a forecasting model, to predict the expected impact of solar events on satellites at different altitudes between 300-800 km. For the realization, scientific data, such as kinematic orbit information and accelerometer measurements, from a wide variety of satellites will be incorporated. Through a joint analysis and evaluation of solar wind plasma and magnetic field data observed at the Lagrange point L1, first preliminary results of predicted thermospheric density increases and associated satellite orbit decay rates are shown.