A control system for a satellite comprises a power source and control system, a propulsion system having individually selectable solid fuel motors, a communication interface and an attitude determination and control system (ADCS). The ADCS receives power from the power source and control system and further receives desired orbital or positional instructions via the communication interface. Based on the desired orbital or position instructions, the ADCS generates and provides commands to the propulsion system. In turn, the propulsion system selects and fires one or more motors of the individually selectable solid fuel motors responsive to the commands received from the ADCS. A satellite may comprise the disclosed satellite control system as well as attitude control components and/or sensor components operatively connected to the satellite control system.

A control method for controlling a momentum wheel device for stabilizing a spacecraft includes: providing the momentum wheel device as a real momentum wheel device having a momentum wheel driven by a motor; providing a simulated momentum wheel device based on an ideal physical model; concurrent feeding of a torque command to both momentum wheel devices, to change a rotational speed of both momentum wheel devices; controlling the motor to change the rotational speed dependent on the fed torque command; detecting a real rotation angle of the real momentum wheel device; calculating a simulated rotation angle of the simulated momentum wheel device by two-fold integration of the fed torque command; comparing the real rotation angle and the simulated rotation angle and generating an error signal corresponding to a deviation between the real and simulated rotation angles; and controlling the motor due to the error signal to reduce the deviation.

Provided is a three-dimensional rigid ball driving system including: a support frame having a polyhedral shape; a rigid ball positioned at the center of an inner portion of the support frame; a plurality of ball bearings installed at corners of inner sides of the support frame, respectively, and contacting a surface of the rigid ball; and a plurality of electromagnets disposed around the ball bearings and generating magnetic fields to rotate the rigid ball; and a controller controlling the electromagnets to control a rotation direction and a rotation speed of the rigid ball.

Energy efficient satellite maneuvering is described herein. One disclosed example method includes maneuvering a satellite that is in an orbit around a space body so that a principle sensitive axis of the satellite is oriented to an orbit frame plane to reduce gravity gradient torques acting upon the satellite. The orbit frame plane is based on an orbit frame vector.

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 spacecraft has a flat antenna array having an edge and a middle portion. A reconfigurable reaction-momentum wheel is coupled to the antenna array to roll and/or pitch the antenna array in small magnitudes. The reconfigurable reaction-momentum has a reaction operating state or mode (high-torque, low momentum) and a momentum operating state or mode (low-torque, high momentum). A thruster is coupled to the antenna array to move the antenna array.

A dual stage vehicle attitude control system includes a first attitude control module having at least two momentum wheels arranged to provide zero momentum vehicle attitude control, each momentum wheel comprises a limited travel two axis gimbal that pivots the momentum wheel along two of the three axes of the vehicle, a second attitude control module having reaction wheels arranged in a pyramid configuration to provide vehicle attitude control along at least one control axis that is common with a control axis of the at least two momentum wheels, and a controller connected to the first attitude control module and the second attitude control module, the controller being configured to coordinate actuation of the first attitude control module and the second attitude control module to rotate the vehicle in at least one of three axes of a vehicle.

A method of determining one or more inertial properties of a spacecraft. The method comprises: receiving data collected at different points in time during operation of the spacecraft. The data includes information indicative of: the angular momentum of a reaction wheel on-board the spacecraft, and the angular velocity of the spacecraft. The method further comprises: identifying changes in the angular velocity of the spacecraft based on the information indicative of the angular velocity of the spacecraft; and determining one or more inertial properties of the spacecraft based on the identified changes in the angular velocity of the spacecraft and the information indicative of the angular momentum of the reaction wheel.

A method of determining one or more inertial properties of a spacecraft. The method comprises: receiving data collected at different points in time during operation of the spacecraft. The data includes information indicative of: the angular momentum of a reaction wheel on-board the spacecraft, and the angular velocity of the spacecraft. The method further comprises: identifying changes in the angular velocity of the spacecraft based on the information indicative of the angular velocity of the spacecraft; and determining one or more inertial properties of the spacecraft based on the identified changes in the angular velocity of the spacecraft and the information indicative of the angular momentum of the reaction wheel.

A rotational negative-inertia converter (RNIC) has a housing enclosing a flywheel configured to rotate around an axis of symmetry; a motor with a stator attached to the housing and a rotor attached to the flywheel to rotate it around the axis of symmetry; a housing angular accelerometer attached to said housing; a flywheel angular accelerometer; and a controller configured to receive measured accelerometer values from the accelerometers. The controller is configured to drive the motor to maintain the angular acceleration of the flywheel at a value proportional to the housing angular acceleration, with a predetermined proportionality constant. A method for calibrating an ADCS testbed comprising a DUT holder with three RNICs includes: using measured angular velocities of the DUT holder and RNIC flywheels, and ZGT data, to compute moments of inertia of the DUT holder with and without a satellite with ADCS, allowing compensation for those moments by the RNICs.