Capabilities and Boundaries of Model-Based Systems Engineering Tools: An Evaluation of Virtual Satellite and Capella for Space Application

Kurzfassung

In Model-Based Systems Engineering (MBSE), models are used for the formalized description and specification to simplify the structuring of complex technical problems and facilitate the exchange of information between expert groups. A key objective is to continuously ensure the functionality derived from the requirements of the product during its development. Ideally, this is achieved through automated plausibility checks that analyze the e!ect of the design adjustments. The software Virtual Satellite developed by the German Aerospace Center (DLR) is a tool for MBSE. Beginning in the early design and development phases, systems can be described as digital models. In addition to working together in a team on a uniform digital representation of the considered system, Virtual Satellite allows extensions of its basic data model with corresponding functionalities. Capella is also a tool for MBSE which was developed by Thales. It was developed for the model-based development method ARCADIA, which is from Thales as well. Using this method, it is possible to represent an entire development process starting with user needs (stakeholder analysis) to system integration, validation, and verification (IVV). This is achieved by using di!erent perspectives on the system and special diagrams that are interconnected. In this bachelor thesis, both MBSE tools Virtual Satellite and Capella are evaluated. At first, a current project (QYRO) of the DLR Galileo Competence Center is modeled in both environments which creates a common basis for the evaluation. Based on the evaluation, the two tools are then directly compared to each other. Thus, the strengths and weaknesses of both tools can be shown and a recommendation for future use of the MBSE tools can be developed. These analyses have shown that both tools work in very di!erent ways and therefore have di!erent strengths and weaknesses, which means that they complement each other in some aspects. Virtual Satellite profits from its storage of concrete information of real product data in the later phases, whereas Capella shows significantly more strengths in the early project phases because of its simplified and abstract representation. By using Capella, the system to be developed can be understood fundamentally through the abstractions, and throughout a later use of Virtual Satellite, the system can be analyzed for weak spots and then actually be built. Virtual Satellite has more potential for further developments, on the one hand since the software is still being developed and on the other hand because of its modular concept structure which makes it easier to integrate extensions that can be used to analyze the system in the future. Capella covers more relevant aspects of systems engineering by not only considering the system but also its environment and all stakeholders of the system. Here, interactions within the system and its environment can be considered. The results imply that the use of Virtual Satellite has advantages over Capella primarily when comparing specific configurations of a system. The use of Capella in projects, on the other hand, can cover the actual development process and be used better for more complex systems since the perspectives can represent it as detailed as needed.