Abstract :
Planning for the fullest possible scientific utilization of the initial group of U. S. satellites is proceeding actively under the supervision of the National Academy of Sciences and its appropriate Panels and Working Groups. An inert satellite, tracked from an array of ground stations, will provide a means of unprecedented precision for the determination of the geodetic figure of the earth, for the transoceanic linkage of mapping networks, and for the measurement of atmospheric density at very high altitudes. A variety of physical observations with active, on-board instrumentation has been considered. The highest "flight-priority" has been assigned to the following:a) the monitoring of the intensity of the solar ultraviolet; b) the monitoring of cosmic ray intensity and the measurement of its latitude, longitude, and altitude dependence; c) the measurement of the size spectrum and the number density of interplanetary dust; and d) the measurement of the earth\´s optical albedo over large areas. A concerted attack on the technical problems of successful on-board observations is being made.