Patent ID: 9180983
Filing Date: 2015-11-10
Classification: B64G

Abstract:
1. An attitude control actuator, to be fixed in a spacecraft with respect to a reference system linked to the spacecraft, the actuator comprising: a first momentum wheel; at least one motor arranged to drive in rotation said first momentum wheel about an axis of rotation of said first momentum wheel; and a second momentum wheel arranged to rotate about an axis parallel to or coinciding with the axis of rotation of the first momentum wheel, wherein the second momentum wheel is mechanically coupled with the first momentum wheel through a mechanical coupling means comprising a variable rotation speed drive, said mechanical coupling means imposing a negative ratio (R), of a rotation speed of the second momentum wheel to a rotation speed of the first momentum wheel, resulting in contra-rotating first and second momentum wheels, said ratio (R) being continuously modifiable between a minimum value and a maximum value by transferring kinetic energy from one wheel to the other wheel when the first and second momentum wheels are rotating by the coupling means in response to a command.