Reaction Spheres for Attitude Control of Microsatellites

Research output: ThesisDissertation (TU Delft)

5 Downloads (Pure)


In past decades, small spacecraft have raised worldwide interest for their low cost and short development time. In general, three reaction wheels are needed for three-axis attitude control of general satellites. However, for small spacecraft where both volume and power budgets are limited, employing three wheels is a challenge. Therefore, reaction spheres are proposed as a replacement for reaction wheels. In a reaction sphere, the spherical rotor is driven by forces generated between the stator and the rotor. Since the rotor’s spin axis and the output torque could be about any desired axis in the 4¼ space, a single reaction sphere could be sufficient to implement three-axis control. Till today, various reaction spheres have been developed, but their performances are far from satisfactory. A better understanding of reaction spheres is needed and great improvements of these actuators are expected especially for small satellites. This dissertation aims at performance modeling of reaction spheres. Through the modeling process, restricting factors of performances and possible improvements are investigated. This work is focused on induction-based reaction spheres (IBRSs), which are selected as the most promising type of reaction sphere for applications to small spacecraft.
Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
  • Delft University of Technology
  • Guo, J., Supervisor
  • Gill, E.K.A., Supervisor
Award date28 Oct 2021
Print ISBNs978-94-6366-460-8
Publication statusPublished - 2021


  • reaction sphere
  • electromagnetic induction
  • field modeling
  • performance analysis
  • motion coupling


Dive into the research topics of 'Reaction Spheres for Attitude Control of Microsatellites'. Together they form a unique fingerprint.

Cite this