Upper-atmosphere studies by ranging to satellites

Abstract

A satellite moving through the upper atmosphere is subjected to aerodynamic forces which may appreciably alter its orbit, and the properties of the upper atmosphere have in the past been successfully studied by determining orbits from photographic, visual and radar observations, and analysing the changes in the orbits. Laser observations of satellites in orbits with perigee height 400 km or less should allow much more accurate orbit determination, and hence improved information on the atmospheric parameters. In particular it may be possible to determine upper-atmosphere winds and scale height with a much better time resolution - perhaps daily. There seems to be a good chance of suitable satellites being launched, and the difficulties of accurate prediction for the laser tracking, though serious, should not be insuperable.