A method for controlling the orbit of a satellite in earth orbit. The orbit of the satellite is controlled by commanding, according to a maneuver plan, a propulsion system having at least one thruster and a transporter to move the propulsion system. The maneuver plan includes at least two orbit-control maneuvers. The thrust powers of the propulsion system during the two orbit control maneuvers have respective thrust directions that are not parallel in an inertial frame of reference. Each thrust power is determined to simultaneously control the inclination and the position of the orbit of the satellite as well as to form a momentum that is suitable for unloading a device for storing angular momentum of the satellite in a plane orthogonal to the direction of thrust of the thrust power.

A control moment gyroscope (CMG) module for use in a satellite comprising a CMG, the CMG comprising a flywheel assembly mounted on a gimbal assembly, the flywheel assembly comprising a flywheel rim, a flywheel spokes member and a flywheel shaft, the flywheel rim circumscribing the flywheel shaft, and the flywheel spokes member extending between the flywheel shaft and the flywheel rim. The gimbal assembly comprises at least one gimbal and a spin motor, the spin motor for rotating the flywheel assembly about a first axis. The CMG further comprises a torque shaft and a torque motor for rotating the at least one gimbal about a second axis. The CMG module further comprises a hermetic first shell housing; and a hermetic second shell housing; wherein the second shell housing is joined to the first shell housing by a hermetic seal to form an airtight interior of the CMG module, the interior of the CMG module containing the CMG.

An improved spacecraft actuator wheel is provided which can be operated as a momentum wheel, a reaction wheel or a gimbal. The actuator wheel has a central cavity. One or more battery modules are located within the actuator wheel's central cavity. The battery modules supply power to one or more electronic components affixed to the actuator wheel or mounted on the spacecraft frame via an electrical harness. In addition, the actuator wheel's central cavity is pressurizeable for storing spacecraft propellant which can be controllably diverted to the spacecraft's thrusters through conduits and flow valves.

A dual guidance gyroscopic actuator comprises, a main structure connected to a platform, connected to a satellite, a ring, a U-shaped cradle, having first and second ends and a central part, a flywheel mounted on the central part between the first and second ends, being rotationally mobile with respect to the cradle about a first axis. A first bearing is positioned at the first end and a second bearing is positioned at the second end connecting the ring to the cradle, the first and second bearings rendering the cradle rotationally mobile with respect to the ring about a second axis substantially perpendicular to the first axis. The ring is connected to the main structure. The gyroscopic actuator comprises at least one suspension element limiting microvibrations from the cradle and flywheel and at least one end-stop element limiting travel cradle and of the flywheel with respect to the main structure.

Systems and methods for describing, simulating and/or optimizing spaceborne systems and missions. Configurations for spaceborne systems are generated and validated based on simulation output.

A propulsion system for controlling the orbit of a satellite in earth orbit comprises a thruster suitable for delivering a force along an axis F, and a motor-driven mechanism linked on the one hand to the thruster and on the other hand to a structure of the satellite, said motor-driven mechanism being suitable for displacing the thruster on either side of the plane of the orbit and suitable for orienting the thruster so as to make it possible to control a component perpendicular to the orbit of the force in two opposite directions, to control the inclination of the satellite, and in that said motor-driven mechanism is suitable for displacing the thruster along an axis V parallel to the velocity of the satellite, and suitable for orienting the thruster so as to make it possible to control a component of the force on the axis V, to control orbit.

A monitoring system for a satellite is disclosed. The satellite includes a bus, an optical sensor configured to optically detect objects in a first zone extending from the satellite, and a solar assembly comprising a solar panel and a radar device. The radar device can be configured to detect objects in a second zone, different from the first zone, extending from the satellite in a direction transverse to a surface of the solar panel.

A method is described for avoiding gyroscopic singularities during attitude correction to a system, such as a spacecraft having a CMG array. The method receives a corrective torque vector and gimbal angle values for each of at least three gimbals within the CMG array. The method generates a Jacobian matrix A as a function of gimbal angle values . The method calculates a determinant D of Jacobian matrix A. If the determinant is not equal to zero, it is not singular, and the method calculates a gimbal rate {dot over ()} using a pseudo-inverse steering law equation. If the determinant is equal to zero, it is singular, and the method calculates a gimbal rate {dot over ()} using a singularity avoidance steering law equation. The gimbal rate {dot over ()} is output and can be applied to a CMG array resulting in applied torque to a spacecraft and attitude correction.

A system and method for preventing a gimbal from exceeding a predetermined gimbal rate limit includes receiving a gimbal rate command and a gimbal rate feedback signal representative of sensed gimbal rate. The gimbal rate command and the gimbal rate feedback signal are compared, in a control circuit, to determine a gimbal rate error. A predetermined gain scaling factor is applied, in the control circuit, to the gimbal rate command to generate a scaled gimbal rate command. The gimbal is disabled when the gimbal rate error is greater than or equal to the scaled gimbal rate.

The present invention relates to attitude control and, in particular, to control of the attitude of a space platform. The space platform may take the form of or be part of a satellite and/or a spacecraft. An aspect of the present invention concerns the use, in an attitude control system, of several control moment gyroscopes with limited gimbal revolutions. Another aspect of the present invention concerns an improved logic for controlling a control moment gyroscope assembly of an attitude control system.