Traditionally design teams (even the ones applying concurrent engineering) are point based oriented : the team focus on one or a restricted number of designs defined very early in the process and enhance them until they fulfill the user needs and reach a certain “value”, this lead to a lot of iterations and do not guaranty that an optimal design is found. On the opposite, set-based concurrent engineering (SBCE) is a lean approach and a set of associated tools that promote the research of an optimal set of solutions by starting from the complete design space and reducing it by gradually eliminating design space regions as the team gain knowledge on the solution (resolving knowledge gaps). The objective is embrace a systematic approach to the search of optimal solutions for space systems. SBCE has been applied successfully on some Thales Alenia Space missions, the methodology permit to capture value for the client, progressively the link between design parameters and this value, the areas where the team has to lean, … this provides a clear guidance to the team and a systematic approach to system design. But maintaining large influence diagrams and trade-of curves manually reduce our capacity to scale the approach to very large and complex systems such as space systems. Introducing models to support the approach is believe to be an innovative solution to scale the approach and the proposed activity aims demonstrating this. This will lead to the definition of a new class of models, ie most of the time the models considered in MBSE approaches are models describing the solution, here it is proposed to model design spaces, influences of design choices and value, addressing the design activity occurring before the introduction of traditional MBSE models (like Arcadia/Capella ones).