Modeling Space System to provide global coherency from design to operations phases

There is a big semantic “gap” between textual information spread into the many documents (space system manuals, etc.) used in operations and what is really produced (software, hardware, procedures, spacecraft database, etc.) and used for validation (simulators, test beds, failure analysis tools, etc.). Operational user is “taken between” a huge amount of documentation and the very low level information spread into many different specialized formalisms and tools. It is very difficult to get quickly the information necessary to understand how the system works, which is a key point for many operation tasks like the design of operational procedures, alarm or error analysis, etc. A formalized model that captures the system knowledge would not only help designers and operators to catch it much more efficiently rather than in documents, but this may also be used by the computer to ease the many verification and validation tasks to be done, and may enable to keep a more efficient traceability with requirements during the whole system life-cycle. Some attempts to go towards this formalized, global and centralized system view have already been made, for instance with the “Space System Model” from the European ECSSE-ST-70-31 standard. However, it needs to be much more enriched to take into account all the different views of the system and obtain all the expected benefits. In this paper, we present the results of a CNES R&T study called EGPO done with the help of ATOS Company to go further in this direction, initiating a richer view of the space system, and formalizing it with a customization of the SysML standard to the space domain.