The Magsat three axis arc second precision attitude transfer system

The Magsat Attitude Transfer System (ATS), which provides attitude alteration in pitch, yaw, and roll is described. A remote vector magnetometer extends from Magsat on a 20 ft boom, requiring vector orientation by reference to coordinate axes determined by a set of star mapping cameras. The ATS was designed to perform in a solar illuminated environment by using an optically narrow bandwidth with synchronous demodulation at 9300 A. The pitch/yaw optical design, the electrooptics, and signal and switching diagrams are provided. Simple mirrors with no moving parts are placed on the magnetometer to reflect a collimated beam from the ATS for attitude indication, which is accurate to one part in 96. Alignment was completed within 24 hr after launch.