Spacecraft use many motion control systems during normal operations, such as opening door latches, moving cameras and antennas, or positioning solar panels. Actuators are used in motion control systems to move objects or components by converting electrical, pneumatic, or hydraulic energy into mechanical force that is applied to a load to control its movement. Here, we’ll look at some common ways space-rated brakes are used in outer space and spacecraft actuation applications.

Electromagnetic Brakes in Space-Rated Actuator Systems

Electromagnetic brakes are an integral part of the many motion control systems that automate the movement of equipment and components found in spacecraft and outer space.

Some examples include actuator brakes for:

  • Locking and latch systems
  • Docking mechanisms
  • Cargo door activation
  • Robotics
  • Thruster control
  • Antenna control
  • Camera movement
  • Solar panel adjustments

Different electromagnetic brakes are used in actuator systems to decelerate, stop, or hold loads. Common types include:

  • Magnetically Engaged (Power-On Brakes). A metal armature sits on the face of the brake unit, and the magnetic field generated by the supplied current attracts and holds it to the brake face. This generates the braking force.
  • Spring Engaged(Power-Off Brakes). These brakes engage when power is turned off, which disables the electromagnetic field. The spring pushes the armature against a friction plate, which generates the braking force.
  • Friction Brakes. Friction brakes can engage dynamically and offer infinite resolution, meaning they can engage at any point around their 360° surface.
  • Tooth Brakes. Tooth brakes offer higher torque in a smaller package than friction brakes; however, they cannot engage dynamically or with infinite resolution.

Electromagnetic Space Brake Applications

Four main applications of electromagnetic space-rated brakes include:

Thrust Vector Control (Position Control)

Thrusters typically utilize rotary actuators to control the motion of a spacecraft. These actuators generally rely on spring-applied, or power-off, brakes. When power is removed, the brake engages, allowing the actuator to hold the position of the thruster.. When power is on, the brake disengages and the actuator can move the nozzle in a different direction.


Satellites use rotary and linear actuators to hold equipment in position, especially components with arm-type architectures. These actuators rely on spring-applied, or power-off brakes to maintain their position. Examples include solar panels, antennas, cameras, and the fins that guide a satellite’s orbital path. Space brakes can also prevent components from moving due to shock or vibration during launch. When power is applied to these brakes, the actuator can change position.

Docking & Latching

Space brakes are used in space docking and latching systems, which incorporate linear and rotary actuators. This technology is the international standard for interfacing with the International Space Station (ISS). Power-off, or spring applied, brakes are placed at the back of the motor and hold latches open during docking. Once docking is complete, these brakes engage and hold the actuator in place. These brakes are also used within separation and umbilical actuators.

Lunar and Martian Rovers

Servo motors are used in the actuators on the wheels of lunar and martian rovers. Once the motor slows and stops the wheels, power-off, or spring-applied, brakes hold the wheels in their stopped position, similar to a car’s parking brake.

Electromagnetic brakes are also used to control the arm movement of rovers’ drilling apparatuses, as well as hold the position of solar panels, antennas, cameras, and more.

For more information about how our electromagnetic brake products can be used in outer space, visit our aerospace industry page.

Learn More About EM Space Brakes with SEPAC

SEPAC has a long history of developing highly specialized actuator brake technology for challenging and unique situations, including spacecraft and outer space applications.

Our team manufactures industry leading standard electromagnetic brakes and spring-engaged brakes, while bringing our experience and expertise to custom design, and advanced product engineering. All our motion control products are produced and quality ensured in our AS9100 and ISO 9001-certified facility.

Contact us to learn more about our space-ready brake technology, or get a quote for your next aerospace project.

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