orbiting geophysical observatory
any of a series of six unmanned scientific satellites launched by the United States from 1964 to 1969. Equipped with a complex of magnetometers, these orbiting satellites were designed to study the Earth's magnetosphere (i.e., zone of strong magnetic forces around the planet) and its effect on high-energy particles emitted by the Sun. These studies included investigations of auroral displays, magnetic storms, and other related phenomena.
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