Conduct a formal FDI architecture analysis for AOCS mode and especially for safe mode and deorbitation mode.

The activity will focus on two specific modes which are under review for general or legal purposes: safe mode and deorbitation mode.In order to maximize commonality and reuse across all future platforms, a generic safe mode appears an interesting option combining magnetic actuators and the propulsion system. It performs similarly on any orbit with any spacecraft, making the most of the advantages of both technologies. However it introduces extra complexity compared to all-magnetic safe modes.Strict observation of the 25-year deorbit deadline by new developments will require detailed understanding (and mitigation) of the failure cases which might prevent a given spacecraft from achieving the required orbit modification at the end of life. By conducting a thorough, multi-level Fault Detection and Isolation (FDI) analysis (at the equipment, function and mission levels), we can :-determine how to maximize the probability of successful deorbiting while minimizing the extra cost of adding redundancy to existing AOCS architectures or of an independent deorbit "package". -prove that the safe mode does not represent an increased risk, while it simplifies development, validation, and operations.The TRP will develop a generic multi-level FDI analysis approach for early design phases (phase 0/A) which would allow easy trade-off between various system architectures.