Model-Based Systems Engineering Approach for Requirements Derivation in Reusable Launch Vehicles

In recent years, the space industry has witnessed a paradigm shift with the growing adoption of Reusable Launch Vehicles (RLVs), driven by the need to reduce launch costs, minimize environmental impact, and increase mission frequency. Reusable Launch Vehicles (RLVs) have emerged as a critical solution, with operational systems like SpaceX’s Falcon 9 demonstrating the feasibility and benefits of reusability. This prompted other governmental and commercial initiatives to make RLVs a central focus in current and future launcher development. However, the design of such systems introduces new technical and operational challenges, namely ensuring safe atmospheric re-entry and enabling rapid turnaround with minimal refurbishment. This work presents a Model-Based Systems Engineering (MBSE) approach for the systematic derivation and management of requirements for RLVs. Using the Arcadia methodology and the Capella tool, the process ensures rigorous traceability from stakeholder needs to system-level specifications, supporting early validation and multidisciplinary alignment. The analysis begins with the identification of key stakeholder objectives, leading to the definition of a baseline model organized in a modular structure. This allows the user to the adapt the module to various systems, including reusability as a separate module. These high-level capabilities are decomposed into mission-specific phases and associated with realizing activities and functions. Through successive modelling layers (operational, system, logical, and physical), these are translated into functional and technical requirements that support the preliminary design phase. The proposed MBSE framework allows for a unified view of the system, capturing the impact of diverse design drivers and facilitating trade-off analyses across the vehicle’s lifecycle. It also enables the identification of requirements not initially expressed by stakeholders, improving completeness and design robustness. The flexibility of this approach allows it to be adapted to various reusable space transportation architectures—including vertical take-off and landing systems, spaceplanes, and emerging hybrid concepts. In the context of an increasingly competitive and sustainability-driven space sector, MBSE offers a valuable strategy to manage complexity, reduce development timelines, and enhance the reliability and performance of future reusable launch systems.