Effect of Air Drag on the Orbit of an Earth Satellite

Abstract

IN the theoretical formula for the variation of the period of revolution with time, there are three roughly equal small terms, with coefficients e ², H/a ₀ and ɛ (the Earth's ellipticity). Mr. Parkyn obtains a good fit by ignoring the first two of these and retaining the third. It is not altogether satisfactory, however, when two terms which should apparently be included have to be omitted. Rather it suggests that some of the assumptions in the theory need to be improved; that was why we were reluctant to assign a value of H in our article, and we should be even more reluctant to guess its variation with height.