Honda R&D Co., Ltd. has unveiled plans to trial its high-differential pressure water electrolysis system at the International Space Station (ISS) in a collaborative effort with Sierra Space and Tec-Masters.
The move is part of Honda’s broader vision to develop a regenerative fuel cell system capable of supporting human life on the moon by providing advanced energy storage.
The company, which has a longstanding history of hydrogen fuel cell innovation, is aiming to create a circulative renewable energy system that continuously generates oxygen, hydrogen, and electricity.
Under the proposed system, during periods when sunlight is available – analogous to the Lunar Day – the process will use solar-generated electricity to split water into hydrogen and oxygen.
This high-differential pressure water electrolysis system is designed to produce these gases efficiently. In contrast, during the Lunar Night, when solar energy is not accessible, a portion of the oxygen produced will be reserved for astronaut respiration.
The remaining oxygen, combined with the hydrogen generated during the day, will then be used in fuel cells to produce electricity.
The only byproduct from this reaction is water, which is recycled back into the electrolysis system, thereby creating a closed-loop energy cycle similar to how domestic solar systems store excess power for use after dark.
The design of Honda’s system is lightweight and compact, meeting the critical need to reduce transportation costs for lunar missions. By avoiding mechanical compression, the system minimises maintenance requirements, thus enhancing its reliability over long-term missions.
Its capacity to store high-pressure gas in smaller containers also reduces the necessity for multiple large tanks, a significant advantage for space logistics.
Honda plans to validate the core functionality of this system in the microgravity environment of the ISS, using Sierra Space’s Dream Chaser spaceplane for transport, in conjunction with NASA, and relying on Tec-Masters for technical expertise on the ISS. This test represents a key step in assessing the efficiency and dependability of the system for future lunar operations.
The announcement comes after the establishment of Honda’s US Space Development Division in late 2024, a move designed to foster collaboration with the American space industry and promote technological advances for lunar habitation.
