Analysis of satellite laser ranging data to investigate satellite aerodynamics

In Low Earth Orbit (LEO) (under 1500 km) the effects of aerodynamic forces upon the trajectory of a satellite are far from negligible when compared to the accuracy of instrumentation flown on remote sensing satellites. To accurately calculate the net aerodynamic force, the atmospheric conditions and the interactions between the surface and the atmosphere need to be known continuously. There have been few ground-based facilities which have accurately reproduced the space environment in LEO and so there are limited direct experimental results upon which to base interaction models. Using Precise Orbital Analysis (POA) techniques and Satellite Laser Ranging (SLR) data, the aerodynamic orbital perturbations can be isolated and related to the gas/surface interactions. The objectives of this paper are to assess the performance of a number of spacecraft aerodynamic models, and to attempt to improve the knowledge of the gas/surface interactions. Lift to drag ratios greater than 0.1 are found at 800 km, with the “best fit” gas/surface emission being strongly quasi-specular in character.