Since having set a new standard for small, low cost, technology demonstrating satellites, the Delft University of Technology continues development on its PocketQube satellite class to make sure everyone can access space through miniaturised technology. Through its students, the design, testing and integration of various satellite subsystems can be achieved, such as the reaction wheel or magnetorquer. A design of a momentum bias wheel fit for a PocketQube pico-satellite has not yet been achieved, for which this thesis is dedicated. Finding out whether designing and testing a momentum bias wheel using commercial off the shelf or self-manufactured parts is feasible and whether this concept at PocketQube scale is competitive with other attitude actuators. By realising that a reaction wheel delivers a pointing accuracy below 1 degrees and a magnetorquer delivers one above 5 degrees, a perfect range appears in which the momentum bias wheel can operate to fill this pointing accuracy gap. The momentum bias wheel is thus designed to be able to limit the effect of disturbances; internal and external; to a pointing accuracy of 1 to 5 degrees in a nadir-pointing attitude scheme. By setting design requirements based on a statistically determined maximum aerodynamic disturbance torque over one orbit endured during the mission, deriving requirements from the
PocketQube standard, and using the other attitude actuators to derive competitive requirements, a momentum bias wheel design can be created that can be competitive to the other actuators, perform under required environments and achieve the set out pointing accuracy. The momentum bias wheel must be able to attain and maintain an angular momentum of 6.05 𝑚𝑁 𝑚𝑠 due to the aerodynamics disturbance torque estimated at 83.3 𝜇𝑁 𝑚 and must maintain a stability throughout its life of 0.180% as to stay within the desired pointing accuracy, while maximising itself to a power draw of 180 𝑚𝑊 and weighing no more than 41.4 grams. The design is ultimately derived through three trade-off scenarios; for the motor, the flywheel and mounting of the components to each other. As power usage, size and mass are preliminary set requirement due to the fact of the undone system engineering for the next PocketQube mission, these criteria will be approached and are treated as loose requirements. Having settled on a design utilising a Faulhaber vacuum proof 1509B motor and SC1801P speed controller, together with a bronze C67500 alloy lathed flywheel, mounted together utilising two PQ9 PCB’s and an additively manufactured motor mount and flywheel reinforcement, which unfortunately did not meet the size and mass requirement through prototyping, testing the built prototype through operational, micro-vibration, shaker and vacuum tests were the final steps. The operational modes and analysis thereof for only the motor and the complete momentum bias wheel system confirmed that the momentum bias wheel was able to achieve the angular momentum, stability, the pointing accuracy and nadir-pointing requirement, but for more power than maximally allowed. The motor alone was able to perform the required angular velocity at 256 𝑚𝑊 but the complete system was able to perform it at 534 𝑚𝑊. The imbalanced flywheel causes extra torque to be spun at high speeds, which is why the current draw is much high than with only the motor. Through micro-vibration and shaker testing was revealed that the designed mount, although made of plastic for the prototyping phase, was able to survive all its own induced vibrational forces and the launch induces stresses. A small amount of damage to the motor was detected through the decrease in performance post shaker test, meaning the flywheel reinforcement has to be revised. The vacuum test revealed that the steep power increase found during operational testing was due to the increased friction caused by the utilisation of a vacuum lubricant in atmospheric conditions. Conclusively, a COTS momentum bias wheel for a PocketQube is not feasible, as meeting the technical budget requirements of a PocketQube mission is not feasible given the currently available COTS motors. Furthermore, the availability of high velocity miniaturised vacuum rated electric motors is central in the feasibility and competitiveness of wheeled attitude actuators. The competitiveness of this prototype to the proposed PocketQube reaction wheel systems comes down to the motor utilised. Designing and creating a wheeled attitude actuators borders on what is feasibly possible with commercially available parts.