Secure-by-component: A System-of-systems Design Paradigm for Securing Space Missions

Space missions face increasing adversarial threats, making security a more critical concern than ever before. As space becomes congested and contested, the success and safety of these missions rely heavily on the security and resilience of complex systems. Unfortunately, most standards, guidance, and frameworks for space cybersecurity often fall short in emphasizing security as a primary consideration during the initial design phases and are typically applied as an afterthought once the mission is deployed. A secure-by-design approach for space missions should address the wide diversity of missions and the unique characteristics of each one. To tackle this challenge, we introduce secure-by-component, a system-of-systems approach to thinking about secure-by-design for space missions. Our design strategy involves the concept of secure blocks as foundational building blocks for securing space missions. These blocks can be flexibly combined to create secure architectures tailored to meet the unique requirements of each space mission. We demonstrate the usability of our approach by applying it to a critical component of a spacecraft, specifically the star tracker. We discuss the practicality, flexibility, and scalability of our strategy and its applicability to the forthcoming IEEE technical standard on space system cybersecurity. Our proposal is designed to enhance, not replace, top-down approaches to security by complementing existing system engineering strategies. Furthermore, we emphasize that our approach can be readily adopted by individual space organizations and adapted to other domains that include systems-of-systems, highlighting its potential for broad application beyond space missions.