The complexity of space missions arises from a myriad of requirements, dependencies, and interfaces that are dealt with collaboratively by experts of different fields. The exchange of information via documents in textual form is usual, however when dealing with complex missions this approach has many disadvantages. Besides the interpretability of natural language, text does not allow for an abstraction of circumstances. This means that the different experts that are involved have to filter out the relevant information in a painstaking process.
Instead of documents, Model-based Systems Engineering (MBSE) uses formalized data models describing requirements, structure, and behaviour. This makes it easier to visualize complex matters in a better way (e.g. by means of the modelling language SysML) as it allows blanking out unneeded details. Applied changes always flow back into the overall model which facilitates automated plausibility checks and error analyses. MBSE makes it possible to support systems engineering starting from the early concept phase through design and implementation, right up to the verification and validation of the product created.
The Galileo Competence Center analyses, evaluates and applies different MBSE tools in payload projects. The tools used are tailored to the corresponding use cases and further developed. The main focus at the moment is on the two modelling environments Virtual Satellite and Capella.
“Virtual Satellite” is developed by the DLR Institute for Software Technology. In addition to collaborative work on a uniform digital representation of the system under consideration, Virtual Satellite supports flexible extensions of the basic data model with required functionalities. The Galileo Competence Center is working in cooperation with the Institute for Software Technology on the further development of Virtual Satellite based on defined use cases. The current development focus is on modelling and verification of the functional behaviour of a system and the corresponding representation in Virtual Satellite.
The MBSE software "Capella" was developed by Thales and released under open source license in 2015. Capella is based on the "Architecture Analysis and Design Integrated Approach" (ARCADIA) method and is closely linked to it. ARCADIA unifies in itself the methodology, ontology and language used to model in Capella. The software can be used to cover and guide the entire design process, focusing on a diagram-based modelling approach.
The Galileo Competence Center is using Capella for the modelling of the COMPASSO project. On board the International Space Station (ISS), the COMPASSO payload will verify optical clock technologies, and a laser communication terminal for optical data transfer, time synchronization, and distance determination. The goal is to ensure and to efficiently manage the future functionality and reliability of the project during its development with MBSE