Uncovering Fault Behavior in Arm Cortex-M Microprocessors With Core Flight System Under Neutron Radiation

Motivated by the increasing adoption of COTS microcontrollers in New Space missions, this work investigates the behavior of Arm Cortex-M Systems-on-Chip running computational workloads under FreeRTOS with the Core Flight System (cFS) middleware. The research focuses on how cFS interactions and cache configurations influence fault behavior under neutron irradiation. The experiments reveal that incorporating a cache significantly increases all software failure rates, and that adding cFS leads to a higher incidence of I/O-related timeouts. Postmortem analysis of processor states indicated that many timeout events were not indicative of actual operational errors but rather triggers of hardware and software exceptions. Detailed execution tracing revealed that these timeouts were exceptions, and enabling the CPU cache fundamentally altered the fault profile. This finding underscores the importance of understanding how OS-level fault detection and recovery contribute to system reliability under radiation-induced stress.