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A novel closed-loop magnetic attitude control scheme is described for momentum-biased, near-equatorial orbit satellites. Unlike the other schemes proposed so far, the controller presented here performs both the attitude correction and nutation damping, thus obviating the need for a separate nutation damping mechanism. The magnetic torquer is placed along the roll axis of the spacecraft. The roll error , obtained from the Earth sensor, is filtered out into two components; one varying at orbital frequency 0 , and the other varying at nutational frequency ". The control dipole moment .M c of the magneto-torquer is governed by the control law, M c = K 2 n -K' l^0 , where K'j and K' 2 are constants. Analytical expressions for time response of the system and conditions for stability are derived, using linearized equations of motion. The roll/yaw dynamics of the satellite were simulated on an analog computer, and the simulation and analytical results matched well. Also, the simulation results indicate that enough damping is provided in the yaw channel. Design aspects such as choice of feedback gains and saturation characteristics of the magneto-torquer are discussed.

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