The System Integration Senior Engineer will help lead the Nyx system end‑to‑end integration and verification, with a focus on functional platforms (Software in the Loop Platform, Processor in the Loop Platform, Hardware in the Loop Platform, Functional Simulation Facility). You will define and execute test plans, manage requirement traceability, analyse test results, and close verification evidence across SIL/PIL/HIL and physical test campaigns. Working closely with subsystem leads, AIT teams, and external partners, you will identify integration risks, resolve anomalies, and ensure that all mechanical functions perform safely and reliably throughout the mission profile. This position requires a rigorous systems mindset, strong understanding of mechanical behaviour in the space environment, and the ability to lead multidisciplinary verification activities to successful closure.