Torque Compensation Unit (TCU)

RUAG Space Mechanisms is a reference in the development of mirror actuators for in-orbit applications. In order to compensate for the torque generated by the flex pivot guiding the rotation of a mirror, RUAG Space proposed their client to integrate a Torque Compensation Unit (TCU). This mechanism has a similar behavior to a mechanical spring but uses a permanent magnet instead of elastic deformation to generate a force. This technology was successfully implemented in the scanner developed by RUAG Space for the ESA Sentinel-4 mission and needed to be adapted to this new application. Dedicated to the “new-space” industry, the main design driver was to reduce the future production costs.

The Countdown Company was asked to perform numerical analysis of the electromechanical system and propose design modifications. An engineering model and testing model, manufactured on the companies’ premises, were delivered to the client for further testing and integration.

This project was confidential, no pictures or illustrations can be shared.

Collaboration and Timeline


  • With:┬áRUAG Space Mechanisms
  • Date: February 2021
  • Duration: 2 months

Julien Rey
Malo Goury du Roslan