It is proposed that a viscous damping action be used to damp the librations about the local vertical of an elongated satellite vehicle in orbit about the earth. The passive damping effect is investigated by studying the motion of an ideal dumbbell-shaped satellite in orbit about the earth. The dumbbell cannot bend but the point masses are free to move in or out from the center of mass of the dumbbell against the restraints of a simple spring and viscous damper mechanism. The four equations of motion are derived, simpli¬fied, and compared to the equations of motion for a rigid dumbbell and for a single point mass. The complete equations are solved on a digital computer and the solutions analyzed. The results show that the passive damping action is effec¬tive for unperturbed circular orbits. The damping action shows little effect on the 11brations in an elliptical or¬bit. No effect could be noticed on the orbit. Conclusions and recommendations based on the solution are stated.
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