Gravity-Gradient Stabilization Studies with the Dodge Satellite

The DODGE satellite was launched on July 1, 1967 into a near-synchronous orbit to demonstrate gravity-gradient stabilization at that high altitude and to experiment with various design parameters and damping techniques. This satellite was the first to be three-axis stabilized at high altitude using gravity-gradient techniques. It continues to function satisfactorily to the present date. Stabilization in pitch and roll to better than ±;10 degrees has been obtained. The yaw stabilization of ±45 degrees has been fairly consistent; with the assistance of a small angular momentum flywheel, yaw accuracy of ±20 degrees was achieved. Magnetic damping of the sample-and-hold type and simulated hysteresis were both successful in damping librations. Efforts with the torsion wire suspended damper boom scheme were not successful, probably due to a mechanical bias in the device. A TV camera system permitted observation of the boom bending under the influence of solar heating. Mechanical hysteresis in the boom bending was observed.