Analytical Modeling of the Terrestrial Albedo Torque Applied on Satellites of Various Shapes

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Author(s) N. S. Khalifa | Nihad S. Abd el-Motelep
Pages 421-426
Volume 1
Issue 8
Date August, 2012
Keywords Terrestrial albedo, NASA Total Ozone Mapping Spectrometer (TOMS Project), radiative force, radiation Torque, geocentric equatorial , spherical and cylindrical coordinate systems and LEO satellites.

This paper is devoted to construct a simple model to investigate the terrestrial albedo torque applied on satellites of different geometries. Assuming that the Sun lies on the equator, the albedo irradiance is calculated using a numerical model in which irradiance depends on latitude, longitude and satellite altitude. However, in the present work the longitude dependency is disregarded. A detailed model for the optical properties of the satellite surface is used to evaluate the applied force. This force is formulated using a geocentric equatorial system in which the Earth is considered as oblate spheroid. The albedo torque is formulated for cylindrical satellite, spherical satellite and for satellite of complex shape. Based on the Earth reflectivity data measured by NASA Total Ozone Mapping Spectrometer (TOMS project), the results show that the albedo torque has a significant contribution on the satellites on low Earth orbit. It has a maximum value in the order of for satellite lies on altitude of 200 Km. However, it has a minimum value in the order of for satellite lies on altitude of 2000 Km.

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