Simulation of atmospheric drag effect on low Earth orbit satellites during intervals of perturbed and quiet geomagnetic conditions in the magnetosphere-ionosphere system

In this work, we simulate the effect of atmospheric drag on two model low Earth orbit (LEO) satellites with different ballistic coefficient during 1-month intervals of geomagnetically disturbed and relatively quiet conditions, to understand how solar and geomagnetic activity modulates satellites trajectory in Earth's orbit. Our results showed that geomagnetic disturbances on the upper atmosphere associated with high solar activity caused a total decay of 2.77 km and 3.09 km for SAT-A and Sat-B, respectively during the 1-month period, but only about 0.52 km and 0.65 km, respectively during the interval of relatively quiet geomagnetic condition. The mean orbit decay rates (ODR) of the two satellites are ~90m/day and ~100m/day, respectively during the perturbed regime, while the respective values for the relatively quiet regime are ~17m/day and 21 m/day. Within the two regimes, further analysis and simulation of the satellites' responses during 12-day intervals of elevated solar and geomagnetic activity and exceptionally quiet activity showed that SAT-A and Sat-B decayed by about 1.13 km and 1.27 km, respectively during the former regime, while the respective decay for the latter regime are 0.16 km and 0.20 km. The respective mean ODR are 101.38 m/day and 113.22 m/day (for elevated activity), and 14.72 m/day and 18.52 m/day (exceptionally quiet). Sat-B has larger values of height decay (h) and ODR in both regimes, and therefore affected by atmospheric drag force more than Sat-A, because its ballistic coefficient is higher. The results of our simulation confirm (i) the dependence of atmospheric drag force on satellites ballistic coefficient, and (ii) geomagnetic storms being the leading driver of large-scale disturbances in the coupled magnetosphere-ionosphere-thermosphere systems, and consequently the leading `perturber' of satellites' motion in low Earth orbit. Our model can be useful for situational awareness and mitigation of the potential threat posed by solar activity in modulating satellites trajectories.