As space systems grow increasingly interconnected, autonomous, and mission-critical, the need for advanced cybersecurity capabilities has become paramount. This paper, developed by The Aerospace Corporation in collaboration with the Department of Homeland Security Science and Technology Directorate, outlines eight high-priority research and development areas aimed at improving the cyber resilience of space systems. These areas address key capability gaps related to on-orbit protection, zero trust (ZT) architectures, end-to-end security integration, space-tailored information technology and operational technology IT/OT measures, trustworthy operating systems, and secure interoperability. The work emphasizes the unique challenges faced in space environments, including size, weight, and power (SWaP) constraints, intermittent communications, and the lack of realtime forensics and response mechanisms. It advocates for the development of digital twins, cyber ranges, and formalized Secure-by-Design methodologies, while also promoting future-proof architectures that enable secure AI-driven autonomy. By focusing on these targeted research areas, the space ecosystem can proactively defend against evolving threats and ensure mission assurance in a contested and congested space domain.