About MSCI
MicroWheel 4000 (MW4000) Reaction Wheel


The MicroWheel 4000 (MW 4000), part of MSCIís High Performance Attitude Control product line, is a reaction wheel torque actuator and angular momentum storage device for small satellites. The 4000-series MicroWheel is for satellites requiring up to 4 Nms of momentum storage.

The MicroWheel is a ďsmartĒ sensor/actuator pair. It includes both a reaction wheel, and an optional solid-state angular rate sensor, both of which are operated locally by an embedded micro-controller. The micro-controller implements local speed and torque control loops for the reaction wheel, allowing the reaction wheel to accurately track speed or torque commands from a satellite's attitude control computer.

MSCI is proud of the extensive flight heritage our world-leading MicroWheels have gained. Ė more than 75 years of operational wheel-hours in LEO orbit on multiple missions.


MSCI's MW 4000 MicroWheels provide a simple, drop-in solution to satellite control. With their serial data interface, the MicroWheels perform all motor control tasks internally to generate precisely the torque requested by the Attitude Control System (ACS) computer.


MSCIís state-of-the-art MW 4000 MicroWheels enable satellite designers to vastly improve small satellite pointing capabilities.

The MW 4000ís key capabilities include:

  • Spaceflight-proven design
  • Low power consumption
  • All in one sensing control and actuation solution (with optional rate sensor)


The MW 4000 is the newest in the MSCI Reaction Wheel product line and builds on the strong MSCI Reaction Wheels flight heritage. As the 4000 series is in pre-production, specifications are subject to change.

For current information, download the MicroWheel 4000 Product Brochure


MSCIís Product Assurance program ensures that appropriate quality requirements are established and achieved throughout the design, procurement, fabrication, assembly, inspection, testing, storing, shipping and handling phases of the program. Implementation of the quality requirements ensures prompt detection of deficient or marginal quality and effective corrective action.

Please click here to see more details on MSCIís Product Assurance program.


Workmanship standards are employed throughout all phases of manufacturing, assembly and integration to control the quality of the operation. Standards identify specific acceptance/rejection criteria and are maintained to meet current requirements. Samples or visual aids required to verify acceptable workmanship are subject to review by QA. Please click here to see a list of the workmanship standards that are used at MSCI.

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Microwheel 1000
We are proud of our outstanding flight heritage that continues to exceed all expectations. It is a testament to the quality of the minds at MSCI and to the excellence of their creations.
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