Earth Satellite Observations of the Ionosphere

A number of so-called "First Generation" experiments for exploring the ionosphere with artificial earth satellite vehicles has either been carried out or is planned by the United States and the Soviet Union. The theoretical and experimental bases of these experiments are outlined and discussed, and their limitations emphasized. The first available results are from the Soviet experiments and these are discussed. Finally, a brief consideration is given to the kinds of satellite orbits desirable for ionospheric experiments.