@Article{NwankwoDCAFARCEA:2021:AtDrEf,
               author = "Nwankwo, Victor U. J. and Denig, William and Chakrabarti, Sandip 
                         K. and Ajakaiye, Muyiwa P. and Fatokun, Johnson and Akanni, 
                         Adeniyi W. and Raulin, Jean Pierre and Correia, Emilia and Enoh, 
                         John E. and Anekwe, Paul I.",
          affiliation = "{Anchor University} and {St. Joseph’s College of Maine} and 
                         {Indian Centre for Space Physics} and {Anchor University} and 
                         {Anchor University} and {Anchor University} and {Universidade 
                         Presbiteriana Mackenzie} and {Instituto Nacional de Pesquisas 
                         Espaciais (INPE)} and {Interorbital systems} and {Anchor 
                         University}",
                title = "Atmospheric drag effects on modelled low Earth orbit (LEO) 
                         satellites during the July 2000 Bastille Day event in contrast to 
                         an interval of geomagnetically quiet conditions",
              journal = "Annales Geophysicae",
                 year = "2021",
               volume = "39",
               number = "3",
                pages = "397--412",
                month = "May",
             abstract = "In this work, we simulated the atmospheric drag effect on two 
                         model SmallSats (small satellites) in low Earth orbit (LEO) with 
                         different ballistic coefficients during 1-month intervals of 
                         solar-geomagnetic quiet and perturbed conditions. The goal of this 
                         effort was to quantify how solar-geomagnetic activity influences 
                         atmospheric drag and perturbs satellite orbits, with particular 
                         emphasis on the Bastille Day event. Atmospheric drag compromises 
                         satellite operations due to increased ephemeris errors, attitude 
                         positional uncertainties and premature satellite re-entry. During 
                         a 1-month interval of generally quiescent solar-geomagnetic 
                         activity (July 2006), the decay in altitude (h) was a modest 0.53 
                         km (0.66 km) for the satellite with the smaller (larger) ballistic 
                         coefficient of 2.2×10-3 m2 kg-1 (3.03×10-3 m2 kg-1). The 
                         associated orbital decay rates (ODRs) during this quiet interval 
                         ranged from 13 to 23m per day (from 16 to 29m per day). For the 
                         disturbed interval of July 2000 the significantly increased 
                         altitude loss and range of ODRs were 2.77 km (3.09 km) and 65 to 
                         120m per day (78 to 142m per day), respectively. Within the two 
                         periods, more detailed analyses over 12 d intervals of extremely 
                         quiet and disturbed conditions revealed respective orbital decays 
                         of 0.16 km (0.20 km) and 1.14 km (1.27 km) for the satellite with 
                         the smaller (larger) ballistic coefficient. In essence, the model 
                         results show that there was a 6- to 7-fold increase in the 
                         deleterious impacts of satellite drag between the quiet and 
                         disturbed periods. We also estimated the enhanced atmospheric drag 
                         effect on the satellites' parameters caused by the July 2000 
                         Bastille Day event (in contrast to the interval of geomagnetically 
                         quiet conditions). The additional percentage increase, due to the 
                         Bastille Day event, to the monthly mean values of h and ODR are 
                         34.69%and 50.13% for Sat-A and 36.45% and 68.95% for Sat-B. These 
                         simulations confirmed (i) the dependence of atmospheric drag force 
                         on a satellite's ballistic coefficient, and (ii) that increased 
                         solar-geomagnetic activity substantially raises the degrading 
                         effect of satellite drag. In addition, the results indicate that 
                         the impact of short-duration geomagnetic transients (such as the 
                         Bastille Day storm) can have a further deleterious effect on 
                         normal satellite operations. Thus, this work increases the 
                         visibility and contributes to the scientific knowledge surrounding 
                         the Bastille Day event and also motivates the introduction of new 
                         indices used to describe and estimate the atmospheric drag effect 
                         when comparing regimes of varying solar-geomagnetic activity.We 
                         suggest that a model of satellite drag, when combined with a 
                         high-fidelity atmospheric specification as was done here, can lead 
                         to improved satellite ephemeris estimates.",
                  doi = "10.5194/angeo-39-397-2021",
                  url = "http://dx.doi.org/10.5194/angeo-39-397-2021",
                 issn = "0992-7689",
           targetfile = "angeo-39-397-2021.pdf",
        urlaccessdate = "03 maio 2024"
}