Honda R&D to Conduct Testing with Sierra Space and Tec-Masters on the International Space Station

Honda R&D today announced plans to test its high-differential pressure water electrolysis system at the International Space Station (ISS) in collaboration with leading space and technology companies Sierra Space and Tec-Masters. The project is part of Honda’s vision for a regenerative fuel cell system that could provide advanced energy storage capable of supporting human life on the lunar surface.

Regenerative Fuel Cell System for Outer Space
Honda is leveraging decades of hydrogen fuel cell technology expertise to develop a regenerative fuel cell system, known as a circulative renewable energy system, that will continuously produce oxygen, hydrogen, and electricity. Honda envisions the circulative renewable energy system to be part of the infrastructure for humanity’s sustained habitation on the Moon – utilizing the available resources of sunlight and water. By enhancing the performance of the circulative renewable energy system, improvements can be made to long-life regenerative fuel cells that can be used as a scalable, clean, and renewable energy source both in space and on Earth.   

During the Lunar Day, the system will use electricity generated by the sun to power the process. Honda’s high-differential pressure water electrolysis system will then produce hydrogen and oxygen from water.

During the Lunar Night, when the Moon is not receiving sunlight, some of the oxygen will be used for astronauts to breathe. The Honda fuel cell system will use the remaining oxygen, along with the hydrogen produced during the Lunar Day, to generate electricity.

After the fuel cells generate electricity, the only byproduct is water, which is recycled back into the water electrolysis system to create a closed-loop energy cycle. This process is similar to how a home solar system operates on Earth, where daytime solar electricity is harnessed, and excess energy is stored in home energy batteries to provide power throughout the night.

International Space Station Testing
Honda has developed an advanced water electrolysis system designed to support long-term operations on the Moon by prioritizing efficiency and reliability. The system’s lightweight and compact design addresses the critical need to reduce transportation costs in lunar development. Additionally, since it doesn’t use mechanical compression, maintenance needs are reduced, enhancing reliability for extended missions. By enabling high-pressure gas storage in smaller containers, the system also reduces the need to transport and manage large numbers of tanks.

Honda will test the core part of its high-differential pressure water electrolysis system to verify the efficiency and reliability of the system in the microgravity environment of the ISS. For the ISS testing, Honda is collaborating with Sierra Space, a leading commercial space company at the forefront of innovation and the commercialization of space, and Tec-Masters, a leading provider of innovative scientific and technological solutions. Sierra Space will be the primary space mission integrator, working with NASA to transport materials on Sierra Space’s Dream Chaser® spaceplane, the world’s only commercial spaceplane. Tec-Masters will be the ISS technology expert.