Magnetic control of satellite attitude

ANY METHOD adopted to control the attitude of an artificial terrestrial satellite must be a function of the mission for which the satellite is intended. For short-lived satellites, the almost universal method has been to remove unwanted angular momentum by exhausting mass through a gas-jet nozzle. For long-lived satellites, studies have investigated the possibility of using the earth's magnetic field to dump unwanted angular momentum by controlling the magnetization of a portion of the satellite.
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These studies have been directed particularly toward control of earth-referenced satellites suitable for communication or weather-observatory applications, for example.