Case Study: CSEM SA achieves reduced-weight reaction sphere and extra satellite payload capacity with COMSOL Multiphysics

Reduced-Weight Reaction Sphere Makes Way for Extra Satellite Payload

CSEM SA, the Swiss Center for Electronics and Microtechnology, faced the challenge of reducing mass and vibration in satellite attitude-control systems where every gram can cost ~15,000 euros per kilogram to launch. Instead of the conventional set of three or four reaction wheels, CSEM SA developed a single multi-axis reaction sphere — a roughly 20 cm iron rotor studded with 728 permanent magnets and driven by a 20‑pole stator — and turned to Comsol using COMSOL Multiphysics to model and refine the complex magnet and coil configurations.

Using Comsol’s simulation tools, CSEM SA validated magnetic flux, simulated energized-coil forces, and compared results to test-bench measurements (showing good agreement), enabling rapid design iterations and exploration of novel one‑sided flux designs to remove the iron core and cut mass, coil current and power consumption. Comsol’s models shortened tuning to hours, helped predict developed torques/forces accurately, and supported a path to a lighter, lower‑vibration reaction-sphere that can increase payload margin and improve satellite performance.

CSEM SA

Olivier Chételat

CSEM SA