As industries in various sectors increasingly adopt model-based systems engineering (MBSE) for system lifecycle design and development, engineers can manage and describe systems of higher complexity than ever before. This is especially true for the field of space systems; while past missions have developed using document-based planning, it is only in the last several years that NASA and other organizations in the space industry have begun using MBSE. One crucial factor of space systems development that is often overlooked is cybersecurity. As space systems become more complex and cyberphysical in nature, cybersecurity requirements become more difficult to capture, especially through document-based methods; a need for a means by which to continuously verify and validate systems cybersecurity for cyberphysical space missions arises. By expanding upon a National Institute of Standards and Technology (NIST) framework for cyber resiliency, this work proposes a methodology that uses MBSE traceability functionality to demonstrate adequate cybersecurity for cyberphysical space systems using SysML requirements modeling capabilities. Key goals, objectives, and strategic principles leading to achieving cybersecurity at all levels of the system's architectural hierarchy are presented. Recommendations for the future of space cybersecurity include the addition of the space sector to the Department of Homeland Security Cybersecurity & Infrastructure Security Agency's list of critical infrastructure sectors to improve standardization and control of space cyberinfrastructure.
