Given the space environment’s inherent threats, including space radiation and the rising potential for micrometeoroid and orbital debris (MMOD) impacts, spacecraft designs should aim to attain acceptable performance, reliability, and resilience in response to these challenges. In modern spacecraft design, there is an emerging trend to incorporate protective measures as an integral aspect of the spacecraft’s structural function. The foam-core sandwich panel, or FCSP, is a novel shield with the potential to overcome the limitations imposed by traditional honeycomb sandwich panels (HCSP). Previous numerical analysis and empirical investigations confirm FCSP’s ballistics protection capability. However, like with other sandwich structures, as the size of the threat rises, ballistic performance diminishes, weakening the multifunctional benefits of sandwiches like FCSPs. Therefore, replacing traditional HCSP with FCSP is futile without improving FCSP’s protection against larger MMOD threats. The goal of this Ph.D. research was to devise a multifunctional, weight-efficient FCSP to address dual challenges in space exploration: protection against MMOD and extreme radiation environments. Three core objectives were delineated to fulfill this goal: 1) Develop highly accurate numerical models to represent FCSPs, 2) Enhance the FCSP design to improve its shielding performance against escalating MMOD threats while maintaining structural functions, and 3) Develop an implementable strategy to incorporate the refined FCSP designs in real-world spacecraft applications, including a review of their performance in extreme conditions such as Molniya radiation and Low Earth Orbit (LEO) debris. The research methodology integrated physical testing with numerical simulations, leading to the creation of a detailed FCSP model that accurately simulates hypervelocity impacts. Validation of this model through physical tests confirmed FCSP’s shielding capabilities. Nevertheless, the study identified limitations in shielding against larger MMOD particles, and proposed appropriate solutions, and their practical applications. In pursuit of multifunctionality, the research explored the incorporation of radiation-attenuating materials like polyethylene (PE) and carbon-fibre reinforced composite (CFC), examining their impact on radiation shielding and the influence of composite microstructure on the total ionizing dose (TID). Additionally, the research outlined a practical application of the proposed FCSP design for spacecraft, emphasizing its relevance in enhancing spacecraft design for various orbital scenarios.