Surveying the earth from 20,000 miles

Current space programs aimed at monitoring the earth's resources concentrate on the lower orbital altitudes of 100 to 500 nautical miles. An earth synchronous (geo-stationary) orbit is 19,400 n. mi. above the earth. A powerful telephoto camera at such a location can monitor and record many time-variant phenomena far more effectively than instruments at lower altitudes. The geo-stationary systems characteristics and problem areas related to optics and telemetry are outlined and detailed, and on-going programs are discussed as they relate to the geo-stationary system.