FWF - ESPRIT - The effect of space weather on satellite orbits

Every now and then most of the people have thought about terrestrial weather and its forecast since it plays an essential role in our daily lives. Now, the main focus of project ESPRIT is space weather, which in a certain way can be considered analogous to the weather on Earth. It deals with the dynamic conditions in the Earth’s outer space environment including the physical processes on the Sun, in the solar wind, the magnetosphere and in the upper atmosphere. Accompanying with the rapid technological progress in the last decades space weather effects can directly be perceptible in people’s everyday life. Coronal mass ejections, huge clouds of magnetized plasma, and may lead to perturbations of electronic devices at technical infrastructure on Earth and also in space. Furthermore, they have the capability to interrupt navigation and communication services or even be the trigger for the loss of complete electricity grids, with far-reaching consequences in different areas. With this in mind, it becomes obvious that a precise forecasting of space weather effects is of vital importance. However, compared to the weather predictions on Earth, the forecasting of space weather effects, especially during solar eruptions, is still at the very beginning. The goal of project ESPRIT is the exploration of physical conditions of the solar wind plasma and interplanetary magnetic field parameters as well as solar radiation over varying solar activity levels and during different solar phenomena. On this basis, it is proposed to develop optimized algorithms to improve the modelling of the upper Earth’s atmosphere and the associated determination of satellite orbit decay rates. As we know, certain predominant chemical compositions like NO, CO2 and He in the upper Earth's atmosphere may be the trigger to so called cooling effects. These effects have the capability to counteract the heating processes induced by the enhanced energy input from the solar wind. At first glance, one might think that this is beneficial, because it counteracts the negative effects of solar eruptions on the upper Earth atmosphere. However, since the sources of such cooling effects are not fully understood so far, unforeseen behaviours of the atmosphere are rather a disadvantage, especially for the accuracy of potential space weather predictions. For this reason, it is intended to additionally focus on this important topic in order to incorporate new findings regarding the interaction of heating and cooling processes in the upper Earth atmosphere in the modelling process.