Self-Consistent Calculations of Satellite Surface Potential and the Resulting Drag Coefficient With Varied Ionospheric Composition

The growing number of satellites operating in LEO highlights the necessity for a better understanding of ionospheric aerodynamics to mitigate collision risks, ensure in-orbit safety, and support satellites performing sensitive measurements or carrying precision instruments. Despite the importance of ionospheric aerodynamics, predicting the satellite’s surface potential and the drag coefficient are still challenging. In this study, we share preliminary results of computations where the satellite’s surface potential and the associated drag coefficients are calculated for various combinations of electron and ion densities and temperatures in LEO. The simulations are performed using SPIS and pdFOAM for a satellite with radius rB= 0.3 m. The results show that surface potential varies during the day and night with minimal variation in the absence of sunlight. The corresponding drag coefficient exhibits an increasing trend with rising surface potential but decreases as total ion density increases and it highly depends on the type of the ion. The calculated ionospheric drag coefficient varies in the range of 2.2 ≤ CTot ≤ 4.6. Although the surface potential is higher during the day than night, the greater abundance of H+ at night leads to a higher ionospheric drag coefficient. At 1000 km, the drag coefficient is 2 times larger than the drag coefficient at 300 km. A systematic study of different orientations of the cylinder with respect to the flow as well as various cylinder aspect ratios is currently underway.