Radiation-Hardened and Radiation-Tolerant Motor Control Systems for Aerospace Applications

Executive Summary

Motor control systems are at the heart of spacecraft and aerospace platforms, driving actuators that orient satellites, steer antennas, position solar arrays, and operate robotic mechanisms. Unlike terrestrial environments, these systems must function predictably while exposed to high levels of radiation, thermal extremes, and the absence of convection cooling. Radiation-hardened (RH) and radiation-tolerant (RT) motor control solutions ensure that actuators maintain precision and reliability even in these harsh conditions.

This post explores the importance of RH and RT motor control in space, the challenges designers face, and how embedded intelligence is reshaping subsystem reliability. Devices such as VORAGO’s VA5 family of dual-core Arm® Cortex®-M55 microcontrollers serve as examples of how modern MCUs can integrate compute performance, hardened memory, and motor control peripherals into a space-grade platform, but the broader principles apply across the aerospace and defense industries.

What Does Radiation-Hardened and Radiation-Tolerant Mean for Motor Control?

In space, ionizing radiation can corrupt memory, trigger latch-up, or gradually degrade device performance. Rad-hard microcontrollers embed protection at the silicon and architectural levels so that feedback loops, safety monitors, and control states remain intact without relying solely on shielding. Rad-tolerant devices, by contrast, are designed for missions with lower radiation exposure—such as many low-Earth orbit constellations—where resilience can be achieved by combining selective hardening with architectural and software mitigations.

Both approaches support deterministic motor control under radiation. They preserve telemetry accuracy, keep actuators within safe operating limits, and provide the safeguards necessary to recover from particle strikes without compromising the mission.

Challenges in Designing Space-Grade Motor Control

Motor control in space presents challenges far beyond terrestrial applications. Persistent radiation exposure must be addressed without introducing unacceptable delays or power overhead. Thermal extremes from –55 °C to +125 °C, compounded by vacuum conditions that prevent convection cooling, place significant stress on both devices and power budgets. Precision actuation is also non-negotiable: reaction wheels, propulsion systems, and robotic joints all require tightly bounded latency and jitter to perform as expected. Finally, long qualification cycles—often stretching years—add cost and complexity, underscoring the need for architectures that are both robust and verifiable.

Digital Motor Control as Intelligent Nodes

As discussed in our earlier post on Motor Controls in Space, modern microcontrollers have elevated motor subsystems from simple drivers to intelligent, mission-aware nodes. This evolution allows motor systems to autonomously detect and recover from anomalies, monitor telemetry for predictive maintenance, and adapt energy use to align with mission phases. The reuse of mixed-signal building blocks, such as comparators and ADCs, further reduces system complexity and parts count.

When extended into RH and RT domains, these same principles ensure that intelligence at the node level remains reliable despite radiation events. Recent devices, such as the VA5 family of dual-core microcontrollers, illustrate how these benefits can be preserved in space by combining hardened memory with deterministic compute and networking. While the VA5 is one example, the broader trend is clear: rad-hard and rad-tolerant MCUs are reshaping the role of motor control in spacecraft and defense systems.

Applications of RH and RT Motor Control

Rad-hard and rad-tolerant motor control plays a pivotal role in a wide range of applications. In satellites, it governs actuators for attitude and orbit control, solar array positioning, and payload mechanisms. In exploration and defense missions, it enables propulsion systems, robotics, and high-precision pointing platforms where low-latency actuation is essential. By providing reliable control even under radiation, RH and RT solutions ensure that spacecraft can maintain orientation, conserve energy, and respond to mission demands throughout their operational life.

For example, reaction wheel assemblies benefit from RH controllers that maintain precision over long missions, while robotic manipulators operating in lower-dose LEO environments may employ RT solutions that balance efficiency with resilience. The ability to choose between RH and RT approaches allows designers to match system resilience with mission duration and radiation profiles.

Conclusion

Radiation-hardened and radiation-tolerant motor control is fundamental to modern space and defense missions. From reaction wheels and propulsion control to robotics and solar array positioning, actuators must operate with precision despite radiation exposure, thermal stress, and the absence of convection cooling. Embedding intelligence at the motor-control level, supported by hardened memory, watchdogs, and deterministic networking, reduces component count, simplifies qualification, and extends reliability across mission lifetimes.

While VORAGO’s VA5 family provides a current example of how these principles are applied in practice, the broader takeaway is that RH and RT motor control architectures are enabling spacecraft subsystems to deliver precise actuation, resilient telemetry, and autonomous recovery. These capabilities form the foundation for reliable, long-duration spaceflight and next-generation defense platforms.