Automated FFT verification framework for the ARIEL Instrument Control Unit Boot Software via TCL test sequences

The Boot Software (BSW) of space instruments is mission-critical, ensuring safe and reliable transition from power-on to operational state. This paper focuses on the BSW developed for the Instrument Control Unit (ICU) of the ARIEL payload of ESA’s M4 mission. An automated validation framework has been implemented to verify BSW functionalities via TCL test sequences, covering key services such as request verification, housekeeping, event reporting, memory and time management, connection tests, and on-board parameter management. The validation campaign has been executed on the Spacecraft Interface Simulator (SIS) and across multiple instrument models, with the current campaign performed on the ICU Engineering Model (EM). Results show improved repeatability, requirement coverage, early anomaly detection, and reduced manual effort, with methodology reusable for regression campaigns, Full Functional Tests (FFT), and future in-flight verification.