The Ground Stations to be discussed are the large Radio Stations required for a variety of Astronautical applications. The principle categories are:–

• Radio Astronomy,

• Telemetry and Control,

• Communications,

• Military applications,

and many examples can be found in each category. The Radio Astronomer is interested in the distribution, intensity and spectrum of all extra-terrestial radiations. He will also be interested in telemetry of signals from earth satellites used as observatories beyond the earth's atmosphere. At the other end of the scale, the military authorities are involved in the detection and tracking of hostile satellites as well as the telemetry of data from their own reconnaissance satellites.