XXX-X-XXXX-XXXX-X/XX/$XX.00 ©20XX IEEE Simulation of atmospheric drag effect on low Earth orbit satellites during intervals of perturbed and quiet geomagnetic conditions in the magnetosphere- ionosphere system Victor Uchenna. J. Nwankwo Space-APRAWP Laboratory, Department. of Physics Anchor University Lagos, Nigeria vnwankwo@aul.edu.ng Wahabbi Akanni Department of Mathematical Sciences, Anchor University, Lagos, Nigeria wakanni@aul.edu.ng Jean-Pierre Raulin Center for Radio Astronomy and Astrophysics Mackenzie, Presbyterian University Mackenzie, Sao Paulo, Brazil raulin@craam.mackenzie.br William Denig St. Joseph College of Maine, Standish, ME 04084, USA wdenig@sjcme.edu.net Johnson Fatokun Department of Mathematical Sciences, Anchor University, Lagos, Nigeria jfatokun@aul.edu.ng Emilia Correia Center for Radio Astronomy and Astrophysics Mackenzie, Presbyterian University Mackenzie, Sao Paulo, Brazil ecorreia@craam.mackenzie.br Muyiwa P. Ajakaiye Space-APRAWP Laboratory, Department. of Physics Anchor University Lagos, Nigeria majakaiye@aul.edu.ng Sandip K. Chakrabarti Indian Centre for Space Physics, Kolkata 700084, India sandipchakrabarti9@gmail.com John E. Enoh Interorbital systems, Mojave, CA 93502-0662 enojoneno@gmail.com Abstract—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 ~90 m/day and ~100 m/day, respectively during the perturbed regime, while the respective values for the relatively quiet regime are ~17 m/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. Atmospheric drag, ballistic coefficient,LEO satellites, solar- geomagnetic activity I. INTRODUCTION Atmospheric drag describes the force exerted on any object moving through the atmospheric medium, having orientation in the direction of relative motion with the tendency of slowing the motion of the body. Spacecrafts moving through atmospheric medium experience atmospheric drag force, which constantly takes energy away from the orbit [1-3]. Atmospheric drag is the strongest force affecting the motion of satellites in low Earth orbit (LEO) especially at altitudes <800 km [4]. Solar activity enhances atmospheric drag on Low Earth orbiting satellites (LEOSs) and their effects on the space systems can be profound depending on the severity of solar activity [3]. Atmospheric drag can cause satellites premature re-entry, as well as difficulty in maneuvering, identifying and tracking of satellites and other space objects, and prediction of their lifetime and actual re-entry ([4], and references therein). Premature re-entry of spacecrafts could be due to drag- induced accelerated orbital decay. Under this scenario a satellite gradually decays from orbit (loosing height) and re- enters the Earth atmosphere if appropriate measure or orbit maintenance is not done in timely manner (see, Fig. 1). Examples of spacecrafts that re-entered the atmosphere in the past include Skylab (launched 14 May, 1973, re-entered 11 July 1979), Russian RORSATs, Kosmos-954 (launched 18 September 1977, re-entered 24 January, 1978) and Kosmos-1402 (launched 30 August, 1982, re-entered 7 February, 1983) etc. [3]. The extent to which LEOSs are affected by atmospheric drag also depends on their injected height (h) and ballistic coefficients (B). Satellite’s ballistic coefficient is given by B=C d A s /m s , where C d is the drag coefficient, A s is the projected area and m s is the mass of the satellite. Satellites having smaller values of B experiences less drag force, and 2020 International Conference in Mathematics, Computer Engineering and Computer Science (ICMCECS) 978-1-7281-3126-9/20/$31.00 ©2020 IEEE 10.1109/ICMCECS47690.2020.247003 Authorized licensed use limited to: INSTITUTO NACIONAL DE PESQUISAS ESPACIAIS. Downloaded on December 08,2020 at 19:25:24 UTC from IEEE Xplore. Restrictions apply.