Rotational Speed of the Upper Atmosphere, from the Orbits of Satellites 1966-51 A, B and C

Abstract

THE rotational speed of the upper atmosphere at heights near that of the perigee of a satellite can in principle¹ be evaluated from the change Δi in the orbital inclination i of the satellite. If Λ denotes the ratio of the atmospheric angular velocity to the Earth's angular velocity, Δi is given², as a first approximation, by where ΔT is the change in orbital period, in minutes. In practice the change in inclination, Δi, is often too small to be accurately measurable, and the most accurate values of Λ are likely to be obtained from the orbits for which Δi is largest. We therefore seek orbits which (i) are near-polar and (ii) show a large change in orbital period.