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Abstract

A method, apparatus, article of manufacture, and a memory structure for controlling an attitude and a nutation of a spacecraft spinning about a first axis. The method comprises the steps of measuring a spacecraft attitude rate .omega..sub.1 (t) about a second axis substantially orthogonal to the first axis; generating a rate correction value .alpha..omega..sub.1 (t)/.lambda..sub.0, wherein .lambda..sub.0 is an inertial nutation frequency of the spinning spacecraft, and .alpha. is a proportionality factor; determining a spacecraft attitude angle .phi..sub.2 (t) about a third axis substantially orthogonal to the first axis and the second axis; generating an error signal e(t) as .phi..sub.2 (t)+.alpha..omega..sub.1 (t)/.lambda..sub.0 ; and applying a torque to rotate the spacecraft along the second axis. The article of manufacture comprises a program storage device storing instructions implementing the instructions described above. The apparatus comprises an attitude rate sensor for measuring the spacecraft attitude rate .omega..sub.1 (t) about a second axis substantially orthogonal to the first axis; means for measuring a spacecraft attitude angle .phi..sub.2 (t) about a third axis substantially orthogonal to the first axis; a processor, in communication with the attitude rate sensor, for generating an error signal e(t)=.phi..sub.2 (t)+.alpha..omega..sub.1 (t)/.lambda..sub.0, wherein .lambda..sub.0 is an inertial nutation frequency of the spinning spacecraft, and a is a proportionality factor; and a torquer for applying a torque to the spacecraft along the second axis in accordance with the generated error signal e(t).

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