Author: D. G. King-HelePublisher:
ISBN:
Category :
Languages : en
Pages : 56
Book Description
The accurate prediction of satellite decay dates some months or years ahead remains one of the most difficult and intractable problems of orbital mechanics, chiefly because the lifetime depends strongly on the future variations in air density, which are at present not accurately predictable. In this paper simple graphical methods are presented for estimating the future lifetime of an Earth satellite from its current rate of decay, using theory adapted to an atmosphere with a realistic variation of density with height. The effects of the departure of the Earth and atmosphere from spherical symmetry, and the variations of density with time, are approximated by specifying correction factors. Orbits which experience serious lunisolar perturbations call for numerical-integration methods, and the uses of the computer programs PROD and PTDEC are described. Despite the many uncertainties, the remaining lifetimes of most satellites should be predictable with an accuracy of + or - 10% by these methods, which are based on many years' experience in making the monthly decay predictions for the RAE Table of satellites. (Author).