A reaction wheel detects an angular momentum. A satellite controller selects a target thruster based on the detected angular momentum. A power supply apparatus changes adjustment electric power for the target thruster. A flow rate adjustment apparatus supplies a propellant to the target thruster at a flow rate corresponding to the adjustment electric power. This changes a thrust of the target thruster. When a discharge current of the target thruster does not become a target current, the power supply apparatus further changes the adjustment electric power for the target thruster.

The invention relates to small satellites capable to fly in formation (10), in particular nano- or picosatellites with a mass of 10 kg or less, for LEO applications, comprising a housing (12) and at least one plug-in board (14) arranged in the housing (12) with a predetermined functionality and a propulsion system (16) for generating a directed pulse in the direction of the flight trajectory T.sub.k. It is proposed that the small satellite (10) comprises an independent and autonomously working collision avoidance system (18), which is capable of adapting a trajectory correction T.sub.kk of the trajectory T.sub.k by the propulsion system (16), when a collision with an object (30) is expected. In a further independent aspect, the invention relates to a formation (100) composed of several small satellites capable to fly in formation (10), wherein a relative position and flight trajectory T.sub.k of each small satellite (10) is modifiable via the independently and autonomously working collision avoidance system (18).

This disclosure relates to a satellite attitude control apparatus, comprising a spherical inertial body (1), which is arranged to be rotated in space in a desired rotational mode, one or more rotational feedback sensors. The apparatus further comprises a set of supports (3) and/or actuators (2), whereas one or more actuator is used to create rotational momentum to the spherical inertial body through friction. A set of three or more actuators and supports is used in order to keep the inertial body in place. Three or more supporting elements (supports and actuators) are used in combination with magnetic attraction or four or more supporting elements are used in case magnetic attraction is not in use. Supports can be passive or semi-active in order to reduce friction.

Provided is a reaction wheel assembly ruggedized for use in kinetically launched satellites. An example reaction wheel assembly may include a shaft mounted to a body of a satellite, a wheel mounted to the shaft, wherein a center of a gravity of the wheel is co-aligned with the shaft, and a support device mounted to the body of the satellite. The reaction wheel assembly may include bearings for holding the shaft to the body of the satellite and allowing a rotation of the wheel. The support device can be engaged to support the wheel to reduce a load on the shaft and the bearing, the load being caused by an acceleration of the satellite during a kinetic launch of the satellite. After the satellite is launched into space, the support device can be disengaged from supporting the wheel to allow the wheel to spin.

The present disclosure relates to an axial flux motor comprising a stator and a rotor. The stator comprises a first motor coil, a second motor coil, a first hall sensor, and a second hall sensor, and the rotor comprises a rotor platform member, an actuator magnet array arranged in an alternating axial polarity arrangement, a trigger magnet array, and a rotating magnetic return path member.

An antenna system is configured for use in Low Earth Orbit (LEO) around Earth. The system has a plurality of antenna satellites coupled together to form a phased array. Each of the plurality of antenna satellites have an antenna body with an antenna and a solar cell. A processing device determines an orientation of the plurality of antenna satellites and position the phased array in the orientation based on an analysis of the solar cell of the antenna bodies facing the sun, the antenna of the antenna bodies facing the Earth, and maintaining a torque equilibrium of the phased array.

A control system for a momentum wheel device is specified, wherein the momentum wheel device is a real momentum wheel device (1) and has a momentum wheel which is driven by a motor, and wherein a simulated momentum wheel device (2) is provided which simulates the behaviour of an ideal momentum wheel on the basis of an ideal physical model (12). The rotational speed of both the real momentum wheel device (1) and of the simulated momentum wheel device (2) can be changed by a torque command (6). A comparator device (11) is provided for comparing the real rotational angle (9) of the real momentum wheel device (1) and the simulated rotational angle (14) of the simulated momentum wheel device (2) and for generating a fault signal (15) corresponding to a deviation between the real rotational angle (9) and the simulated rotational angle (14). The fault signal (15) can be conducted to a control device (3), in order to actuate the motor on the basis of the fault signal (15), for the purpose of reducing the deviation.

A satellite attitude data fusion system and method is disclosed, applicable to the earth satellite environment to estimate attitude data of the satellite. When the satellite attitude data fusion system of the present invention is used to perform the satellite attitude data fusion method, the first step is to perform a body rates quaternion attitude data processing operation. Then, the next step is to perform an attitude/rates data fusion processing operation, wherein an attitude data fusion algorithm module receives the first IAE result data from the first EKF, and the second JAE result data from the second EKF, and performs an attitude/rates data fusion algorithm in a subsystem level to evaluate an attitude estimation JAE performance.

A method for desaturating reaction wheels of a spacecraft having a magnetic dipole is provided. The method includes orienting the spacecraft relative to an external magnetic field to apply a torque to the spacecraft via the magnetic dipole in a direction opposing momentum stored in the reaction wheels; and using the applied torque to unload at least some of the momentum stored in the reaction wheels. A corresponding spacecraft and non-transitory computer-readable medium are also provided.

A control moment gyroscope includes: an inner gimbal; a rotor that is held by the inner gimbal to be rotatable around a spin axis; a spin motor that is disposed on the inner gimbal, and that rotates the rotor around the spin axis; a stator that holds the inner gimbal to be rotatable around a gimbal axis that is perpendicular to the spin axis; gimbal bearings that are disposed between the inner gimbal and the stator to face each other from opposite sides of a plane that is perpendicular to the gimbal axis and that includes the spin axis, to be in contact with the plane in question, or to include the plane in question; and a torque module that is disposed on the stator, and that rotates the inner gimbal around the gimbal axis.