## 2 The \({}^{3}\)ColStar Satellite Mission
### Preliminary Design  
The preliminary design process for each subsystem of the satellite platform adhered to a systematic approach that aligned closely with mission requirements. This approach ensured that each subsystem was designed to meet specific functional and performance criteria outlined in the mission objectives. Although actual manufacturing of the subsystems has not yet started, comprehensive design activities were undertaken to lay a solid foundation for future development and integration. This involved an integrated, yet individually focused, subsystem design strategy that fostered effective collaboration among the subsystems. Weekly meetings with all subsystem teams facilitated the resolution of cross-functional issues and ensured cohesive problem-solving across all components. Regarding the comparison with concurrent methodologies, our approach for the preliminary design was selected for its emphasis on sequential development, which was deemed suitable for ensuring thorough validation and alignment with mission specifications. This decision was guided by several considerations:  
1. Validation and Verification: The sequential approach allowed for a detailed analysis and validation of each subsystem's functionality before progressing to the next phase. This was crucial for ensuring that each subsystem met its requirements and integrated smoothly with others, thus reducing the risks associated with subsystem interactions and performance. 2. Risk Management: By focusing on sequential development, risks could be managed more effectively. Each subsystem's design and performance were thoroughly validated before advancing to integration, minimizing the potential for issues during later stages of development. The sequential approach provided a controlled environment for identifying and addressing potential problems early in the design phase. 3. Documentation and Configuration Management: The sequential approach facilitated rigorous documentation and configuration management. Detailed development information for each subsystem was meticulously recorded and updated in a common online repository, ensuring that all stakeholders had access to the most current data. This practice helped mitigate risks related to discrepancies and promoted efficient integration once subsystem manufacturing and assembly commenced. To effectively manage and monitor these design activities, MBSE methodologies were employed. The MBSE approach utilized SysML and Arcadia/Capella frameworks, which provided structured methods for modeling system requirements, architecture, and interactions. By integrating these models into a cohesive system architecture, MBSE enabled early identification of design issues and ensured alignment with mission requirements. Iterative design processes supported by MBSE facilitated simulations and validations, helping to refine subsystem designs and manage risks before physical implementation. Additionally, MBSE tools enhanced documentation and configuration management, ensuring consistent, traceable, and up-to-date information across all design phases. While concurrent methodologies offer advantages such as parallel development and accelerated integration, the sequential approach was deemed more suitable for the preliminary design phase due to its focus on validation and risk mitigation. The integration of MBSE further strengthened this approach, providing a robust framework for systematic design and development. Future projects may benefit from exploring concurrent methodologies to enhance development efficiency, but the current approach provided a solid foundation for ensuring mission success. This section centers on individual subsystem designs aimed at elucidating specific characteristics of each subsystem envisioned for this mission. Next, in Section 3, we will provide a detailed account of our approach using the Capella tool and Arcadia method. Specifically, we will illustrate the systematic progression from requirements to functional, logical, and physical architectures.