An E2ES is a tool used by the Scientists and Engineering teams to simulate the acquisition and generation of the satellite products. There are an increasing number of missions that develop performance simulators in early stages (phase 0/A, B1) to assess requirements, evaluate the instrument characteristics, the products, etc. These simulators often evolve into the operational simulators. The development of a simulators is costly. There needs to be a detailed definition of the architecture for each mission, implementation and a lengthy validation process. To try to reduce the cost, and avoid re-engineering, the BIBLOS project has a step-by-step approach that: