Abstract: For using, on a spin-stabilized satellite, an actuator having an active axis substantially parallel to the spin axis wherein the actuator is activated in a predetermined mode and the resulting nutation period is measured. The actuator is activated in this predetermined mode for at least part of a preliminary step whose duration is equal to a predetermined fraction of the nutation period. This brings the satellite into a configuration in which triggering the service mode of operation induces minimal nutation. The actuator is then activated in this service mode of operation for any predetermined duration. The actuator is then activated under conditions which are the reverse of those of the preliminary step.

Abstract: An attitude control device for a three-axis stabilized satellite in terrestrial orbit embodies an attitude sensing system adapted to deliver roll, yaw and pitch attitude signals, a set of at least three non-parallel axis momentum wheels and a set of at least two magnetic coils oriented at least approximately in two non-parallel directions in the roll/yaw plane. A primary control loop embodies a processor and controller connected between the attitude sensing system and the set of at least three momentum wheels. It is adapted to determine from attitude signals and attitude set point signals attitude correction signals for the momentum wheels so as to apply to the satellite primary attitude correction torques. A secondary control loop embodies a coil controller connected between the processor and controller, the set of at least three momentum wheels and the set of at least two magnetic coils.

Abstract: In order to shift the moment of inertia H.sub.i of a body in rotation initially in rotation approximately about its principal axis of inertia Z into any given orientation H.sub.F one applies transversely to the axis Z three torque impulses in a plane containing H.sub.i and H.sub.F, the first for a time T.sub.1, such that, at the end of one rotation of a satellite about itself, the axis Z shifts to Z.sub.1 in the plane bisecting H.sub.i and H.sub.F, whilst the kinetic moment moves to H.sub.1, the second impulse at the instant when the principal axis of inertia is at Z.sub.1 for a time T.sub.2 appropriate to shift the kinetic moment into a position H.sub.2 symmetrical with H.sub.1 with respect to this bisecting plane, and the third impulse at the instant when the principal axis of inertia is parallel to H.sub.F for a duration equal to T.sub.1.

Abstract: Device for aligning the roll axis of a rotating artificial satellite having radial solar panels equipped with angularly movable control surfaces at their extremities. The device includes a motor associated with each control surface for controlling the angle of the control surface with respect to the solar panel, each motor being actuated by a current which is dependent on the displacement of the roll axis from a desired position and which varies cyclically during the rotation of the satellite. The motor also includes a detector for detecting the angular speed of movement of the control surface and introducing a damping effect.