A rotor assembly for deployment within a momentum control device that enables near-zero revolutions per minute (RPM) sensing, and method for making same, are provided. The provided rotor assembly utilizes a magnet coupled to the rotor shaft and a stationary sensor element to detect magnetic flux from the magnet and derive reliable near zero RPM therefrom.

A modular satellite for converting solar energy to microwave energy and transmitting the microwave energy to the earth to be converted into electricity includes solar panels configured to convert solar energy into direct current; a magnetron operatively connected to the solar panels to receive the direct current and configured to convert the direct current into microwave energy; a planar wave guide antenna operatively connected to the magnetron to receive the microwave energy and direct the microwave energy to a station on earth; and a coupling system for coupling with another satellite to form an array in response to at least one of locking, unlocking, and navigational commands. The satellite has a mass equal to or less than four kilograms, and a volume equal to or less than three liters.

An operation of a spacecraft is controlled using an inner-loop control determining first control inputs for momentum exchange devices to control an orientation of the spacecraft and an outer-loop control determining second control inputs for thrusters of the spacecraft to concurrently control a pose of the spacecraft and a momentum stored by the momentum exchange devices of the spacecraft. The outer-loop control determines the second control inputs using a model of dynamics of the spacecraft including dynamics of the inner-loop control, such that the outer-loop control accounts for effects of actuation of the momentum exchange devices according to the first control inputs determined by the inner-loop control. The thrusters and the momentum exchange devices are controlled according to at least a portion of the first and the second control inputs.

Embodiments of a spherical momentum control device are provided. In one embodiment, the spherical momentum control device includes a housing assembly bounding a cavity, a rotor support axle disposed within the cavity, and a spherical bearing interface formed between the rotor support axle and the housing assembly. The spherical bearing interface facilitates rotation of the rotor support axle within the cavity about three orthogonal axes transecting substantially at the cavity center point. A rotor is mounted to the rotor support axle (e.g., through precision bearings) for rotation about a spin axis. The spherical bearing interface can assume any form for facilitating rotation of the rotor support axle about the orthogonal axes including, for example, a low friction plane bearing interface. In one embodiment, the spherical bearing interface includes rolling element bearings embedded in the cavity walls or embedded in enlarged end caps forming part of the rotor support axle.

Described herein are systems and methods for attitude determination using infrared Earth horizon sensors (EHSs) with Gaussian response characteristics. Attitude information is acquired by detecting Earth's infrared electromagnetic radiation and, subsequently, determining the region obscured by Earth in the sensors' fields of view to compute a nadir vector estimation in the spacecraft's body frame. The method can be applied when two sensors, each with known and distinct pointing directions, detect the horizon, which is defined as having their fields of view partially obscured by Earth. The method can be implemented compactly to provide high-accuracy attitude within small spacecraft, such as CubeSat-based satellites.

A de-orbiting system for a space vehicle may include one or more lithium ion (Li-ion) batteries configured to release hot gases to be used for thrusting during de-orbiting of the apparatus. The system may also include one or more heaters surrounding each of the one or more Li-ion batteries, which are configured to send each of the one or more Li-ion batteries into a thermal runaway. The thermal runaway causes the one or more Li-ion batteries to release stored electrochemical energy within each of the one or more Li-ion batteries.

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.

The present disclosure relates to an axial flux motor for a reaction wheel, and method of using and making the same. The motor includes a stator and a rotor. The stator comprises a printed circuit board (PCB) including a first motor coil. The rotor is coupled to a first ring-shaped magnet having an alternating pole arrangement. In a further embodiment, the rotor includes permanent magnets, and the stator PCB includes a first motor coil, and a first high thermal conductivity element.

A control system configured to execute a safing mode sequence for a spacecraft is disclosed. The control system includes one or more star trackers that each include a field of view to capture light from a plurality of space objects surrounding the celestial body. The control system also includes one or more actuators, one or more processors in electronic communication with the one or more actuators, and a memory coupled to the one or more processors. The memory stores data into a database and program code that, when executed by the one or more processors, causes the control system to determine a current attitude of the spacecraft, and re-orient the spacecraft from a current attitude into a momentum neutral attitude.

A spacecraft attitude control module (1) according to the invention is compact and easy to assemble with additional modules to form an operative attitude control system. The module comprises a robust rectangular, preferably cubic support frame with an attitude control assembly fitted within the confines of the support frame, the assembly including a reference structure comprising a platform, a flywheel support structure (15, 18, 19, 26) and a flywheel (25). The flywheel support structure may be fixed to the platform (10) or it may be a gimbal structure that is rotatable relative to the platform. In the first case the module is a reaction wheel module. In the second case the module is a single gimbal control moment gyroscope module. A preferred embodiment includes a slanted position of the platform (10) relative to the ground plane (100) of the support frame. Another preferred characteristic is the implementation of a flywheel provided with a hollow portion (25′) into which the motor (28) that is driving the flywheel rotation is fitted. The invention is also related to an attitude control system comprising multiple modules assembled together on a support plate (35). The modules may be provided with decking plates (39, 39′) to improve the mechanical robustness of the assembly and to realize fast electrical connections to the modules.