Solid Oxide Fuel Cells for Space Exploration: Enabling High-Efficiency Power Generation in Extreme Environments

The necessity for reliable and efficient power generation in future space exploration missions is paramount, particularly in environments where solar energy is inadequate. Solid Oxide Fuel Cells (SOFCs) emerge as a compelling solution, exhibiting high efficiency, fuel flexibility, and a long operational lifetime. Their capacity to function with hydrocarbons and in situ-derived fuels renders them especially well-suited for long-duration missions. This publication provides an overview of the ESA-funded SOCRATES project, which is investigating the adaptation of terrestrial SOFC technology for space applications in the frame- work of Voyage 2050 and the exploration of Saturn’s moon Enceladus. Based on the Eneramic© SOFC system developed by Fraunhofer IKTS, a breadboard demonstrator is under development to validate the use of pure oxygen as an oxidant and explore different operational modes of recirculation to optimize system efficiency and thermal balance. Unlike terrestrial SOFCs, which typically utilize air, space-based SOFCs must operate with pure oxygen, increasing efficiency while introducing challenges in component and material selection. High-temperature components must resist prolonged exposure to pure oxygen, necessitating careful selection of materials to prevent oxidation, thermal stress, and structural failure. Additionally, SOFCs offer the potential to utilize residual spacecraft propellants for power generation, reducing the need for additional energy storage and improving overall mission efficiency. Integrating SOFCs with a spacecraft’s existing fuel infrastructure can simplify logistics and enhance the sustainability of deep-space missions. The proposed system is designed to provide continuous power for landers, scientific payloads, and robotic missions, particularly in deep-space environments. Key technical challenges include reactant storage, thermal management, and ensuring reliability under extreme conditions, such as the cryogenic temperatures on icy moons. Effective thermal insulation and heat recovery techniques are essential for maintaining efficiency and functionality. The system design also considers insulation requirements, fuel processing techniques, and power conditioning strategies to ensure optimal operation in the harsh conditions of space and to maximize fuel utilization and system performance. Through laboratory validation and breadboard testing, this work aims to advance the TRL of SOFC technology, paving the way for future flight applications. By demonstrating the potential feasibility of SOFCs for space exploration, the SOCRATES project contributes to the development of nextgeneration power systems for sustainable human and robotic exploration beyond Earth’s vicinity.