Introduction to passive nutation dampers
Coning motion can prevent photographic and TV cameras and other oriented spacecraft experiments from maintaining a steady scan, and it can introduce a ripple in the high-gain communication system. Nutation dampers are used to remove this type of spacecraft instability. The first nutation damper flown in a missile for the stabilization of the gyroscope consisted of a hollow ring that was partially filled with mercury, and the sloshing of the mercury dissipated the nutational energy. A similar mercury-ring damper was used in the Pioneer 1 lunar probe in 1958 and became the first nutation damper to be used in space. Since then many types of nutation dampers have been designed for spin-stabilized spacecraft ranging in size from small scientific satellites to large space stations.