Satellite orbital precession caused by a rotating oblate atmosphere with a diurnal variation in density

Abstract

The effect of the motion of the upper atmosphere on satellite orbits of small eccentricity, e < 0.2, is considered. The atmospheric model allows for oblateness, and has a density profile that approximates to the observed day-to-night variation. The equations governing the changes due to zonal (west-to-east) and meridional (south-to-north) winds in the right ascension of the ascending node of the orbital plane Ω during one anomalistic period of the satellite are integrated, assuming that H , the density scale-height, is constant. The resulting expressions for ∆ Ω ω , due to zonal winds, and ∆ Ω Φ , due to meridional winds, are given. It is shown that there can be appreciable changes in ∆ Ω /∆ T D , where ∆ T D is the corresponding change in orbital period, that persist for several months for certain resonant orbits if the diurnal variation in density is allowed for. Compact expressions for ∆ Ω and ∆ Ω /∆ T D are given when H varies linearly with height. It is demonstrated that in general there is no constant value of H that gives an exact equivalence between the variable- H and constant- H equations in the presence of a diurnal density variation.