Optimizing CubeSatellite Orientation Using Magnetorquers

Abstract

This white paper presents a comparative study of magnetorquer-based attitude control solutions for 1U CubeSatellites (CubeSats), with an emphasis on initial detumbling following deployment into Low Earth Orbit. CubeSats experience very high initial angular velocities due to spring-loaded ejection mechanisms in their launch vehicles, often reaching 10–20°/s. To stabilize these small satellites efficiently under strict power, mass, and volume constraints, magnetic actuators known as magnetorquers are utilized. Their application is examined in this white paper.   The analysis begins by outlining three main types of magnetorquers (air-core coils, embedded (PCB) coils, and ferromagnetic rod-core coils) that are compared across various parameters such as mass, torque generation, integration complexity, and power consumption. Control laws such as B-dot, bang-bang, and proportional-derivative (PD) are then evaluated for their ability to bring the spacecraft from a tumbling state to a stable orientation.   Using realistic assumptions and experimental values for Earth’s magnetic flux, satellite inertia, actuator dipole strength, etc., the three configuration models are constructed and simulated. Results suggest that rod-core magnetorquers paired with a bang-bang controller offer the fastest detumbling performance within feasible power budgets, stopping the rotation in under 20 seconds.   Based on these findings, the recommended system for a resource-limited CubeSat prioritizes a 3-axis rod-core magnetorquer array controlled by a hybrid bang-bang and B-dot scheme. This configuration achieves a practical trade-off, i.e., it maximizes torque-per-watt, requires minimal onboard sensing, and avoids moving parts, all while enabling fast, autonomous detumbling with minimal software complexity.