  The performance of Brouwer's gravity solution is compared with Deprit's
second-order radial intermediary. Taking the main problem of the artificial
satellite as the test model, that is perturbations are limited to the effects
of the second zonal harmonic, it is demonstrated that the intermediary solution
provides an efficient alternative for the analytical propagation of low earth
orbits in a range determined by non-impact orbits with eccentricities below one
tenth.
