How can you protect an attitude control system from solar radiation?

1 Sources and effects

Solar radiation consists of electromagnetic waves and energetic particles that originate from the sun and travel through space. The intensity and composition of solar radiation vary depending on the solar cycle, solar flares, and coronal mass ejections. Solar radiation can have a significant impact on spacecraft attitude control systems, such as heating up components and causing thermal expansion or contraction, damaging or degrading sensors, actuators, electronics, and wiring, inducing electrical currents or voltages that interfere with signals and commands, as well as altering the magnetic field of the spacecraft which affects magnetometers and magnetorquers. All of these can reduce the accuracy and responsiveness of the system.

2 Materials and shielding

When protecting an attitude control system from solar radiation, materials and shielding can be used to reduce the amount and impact of radiation that reaches the system. There are several factors to consider when selecting materials and shielding, such as the type and energy of radiation, the mass and volume of the shielding, the durability and compatibility, and the thermal and electrical properties. These factors will determine the thickness and composition of the shielding required, as well as affect launch cost, performance, lifespan, maintenance, heat dissipation, and grounding of the system.

3 Fault-tolerant design and software

An attitude control system can be protected from solar radiation by implementing fault-tolerant design and software. This enhances the robustness and resilience of the system, allowing it to detect, isolate, and correct faults that may arise from radiation effects. To achieve fault-tolerance, redundancy and diversity can be used in components like sensors, actuators, electronics, and wiring. Additionally, error detection and correction codes like parity bits, checksums, and cyclic redundancy checks can identify and fix errors caused by radiation-induced noise or interference. Finally, fault detection, isolation, and recovery algorithms like watchdog timers, health monitoring, and reconfiguration can monitor and restore the system functionality and performance.

4 Monitoring and mitigation

A final way to protect an attitude control system from solar radiation is to monitor and mitigate the radiation damage to the system and the spacecraft. This can help assess and improve the health and safety of the system by measuring, reporting, and counteracting the radiation effects. To do this, radiation sensors and dosimeters can be used to measure the radiation level and dose that the system is exposed to, alerting operators or controllers of any anomalies or hazards. Additionally, radiation hardening and annealing techniques can increase resistance and recovery of system components to radiation damage by modifying their structure or properties. Finally, radiation avoidance and compensation strategies can reduce exposure and impact of the system to radiation by changing the orbit, attitude, or configuration of the spacecraft.