Thermospheric density and wind determination from satellite dynamics The Earths atmosphere is often portrayed as a thin and finite blanket covering our planet separate from the emptiness of outer space. In reality the transition is gradual and a tiny fraction of the atmophere gases is still present at the altitude of low orbiting satellites. The very high velocities of these satellites ensure that their orbital motion can still be considerably affected by air density and wind. This influence can be measured using accelerometers and satellite tracking techniques. The opening chapters of this thesis provide an excellent introduction to the various disciplines that are involved in the interpretation of these observations: orbital mechanics satellite aerodynamics and upper atmospheric physics. Back cover