Patent ID: 8282044

Claim:
Apparatus, comprising an actuator device for varying the attitude of a spacecraft, the actuator device comprising: a reversible conversion chain of electrical energy to mechanical energy, including the following components: a flywheel arranged to rotate about at least one axis of rotation; a reversible operation motor-generator coupled with the flywheel by means of a rotation drive about said axis of rotation; control electronics connected electrically to the motor-generator; a capacitive electrical energy storage assembly connected electrically to said control electronics; and an electrical power converter connected to the capacitive electrical energy storage assembly and which is configured for connection to a power bus of the spacecraft to feed the capacitive electrical energy storage assembly from said power bus, wherein said control electronics are used for: selecting, using at least one set-point representative of a torque to be produced along said axis of rotation and transmitted to said control electronics, either operation in motor mode or operation in generator mode of the motor-generator, and adjusting a transfer of electrical energy from the capacitive electrical energy storage assembly to the motor-generator for the motor mode, or from the motor-generator to the capacitive electrical energy storage assembly for the generator mode, in order to produce an acceleration or deceleration of the flywheel respectively about said axis of rotation, suitable for producing a reaction torque onto the spacecraft corresponding to said set-point.