Honda plans to test a component of its water-electrolysis system on the International Space Station (ISS) to assess how it performs in microgravity. The experiment is not a test of the complete lunar power system Honda is developing, and official announcements reviewed through October 8, 2026, do not establish whether this specific experiment has launched or finished.
What Honda plans to test in space
Honda announced on April 4, 2025, that it had agreed with Sierra Space and Tec-Masters to conduct a microgravity test of a core component of its high-differential-pressure water-electrolysis system. Honda says the test is intended to check the component’s efficiency and reliability in microgravity.
| # | Preview | Product | Price | |
|---|---|---|---|---|
| 1 |
|
HydroCell Kit For Truck | $235.68 | Buy on Amazon |
| 2 |
|
Horizon Fuel Cell Technologies Solar Hydrogen Education Kit | $115.00 | Buy on Amazon |
| 3 |
|
HydroCell PLUS Kit | $349.87 | Buy on Amazon |
| 4 |
|
Hydrogen Fuel Cell Electric Car Hydrogen and Oxygen Power Generation Clean Energy Vehicle Model... | $109.99 | Buy on Amazon |
| 5 |
|
HydroCell Plus | $174.63 | Buy on Amazon |
The distinction matters: the planned ISS experiment concerns an electrolysis component, not the full system Honda envisions using on the Moon. Honda’s 2025 research and development overview also refers to microgravity testing, but gives no dated mission milestone or results for this specific experiment. The official announcements reviewed do not establish a launch or completion date.
How the proposed lunar energy cycle works
Honda describes its regenerative fuel-cell system, also called a circulative renewable-energy system, as a way to store solar power for use during the lunar night. The proposed cycle is:
#1 Best Overall
- Complete kit for gas carburetor engine Cell produces 2.25 LPM at 30 amps
- 1 quart reservoir/bubblier last 1000 miles measures 6"x5"x4" Up To small V8
- Includes PDF copy of our new book Converted. We Work With All Members To Get Them Results
- Converted is the must have PDF for HHO education. Includes installation manuals along with our vehicle database
- Vehicle database shows all cars we/members have installed on, with their MPG results and how acheived
- Collect solar power during the lunar day. Electricity from solar panels powers water electrolysis.
- Split water and store the gases. The electrolyzer separates water into hydrogen and oxygen, which can be stored for later use.
- Generate electricity during darkness. When solar power is unavailable, a fuel cell combines hydrogen and oxygen to produce electricity.
- Recycle the water. The fuel cell’s water byproduct returns to the electrolyzer, continuing the cycle. Honda’s April 4, 2025, announcement says the water is recycled back into the system.
Honda says some of the oxygen could also support astronauts’ breathing. This is a proposed lunar application, not a demonstrated installation on the Moon.
Why Honda emphasizes high-pressure electrolysis
Honda says its electrolysis equipment is designed to be compact and lightweight, avoid mechanical compression, and allow gases to be stored at high pressure in smaller containers. Those are Honda’s design claims; they are not independently measured outcomes from the planned ISS test.
Rank #2
- Horizon puts renewable energy technology into the hands of our future scientists
- Solar Hydrogen Education Kit generates clean energy using the sun
- Renewable hydrogen is created using only solar energy and water
- Combining cutting-edge science, education and fun for all!
- Includes fuel cell, small electric motor, propeller blade, experiment manual and assembly guide
In its 2025 R&D overview, Honda says its high-differential-pressure water-electrolysis technology can supply hydrogen at 70 MPa without a compressor. That figure describes Honda’s stated technology capability, not a result reported from the ISS experiment.
Who is involved in the ISS experiment
Honda’s April 4, 2025, announcement names Sierra Space and Tec-Masters as partners, with Sierra Space serving as the primary space mission integrator and Tec-Masters as the ISS technology expert. Sierra Space’s April 7, 2025, announcement describes the responsibilities in more detail:
The Tool Desk
Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Rank #3
- Complete kit for Large Commercial Diesel engines Cell produces 7 LPM at 30 amps
- 1 quart reservoir/bubblier last 600 miles measures 6"x5"x4" Up To small V8
- Includes PDF copy of our new book Converted. We Work With All Members To Get Them Results
- Converted is the must have PDF for HHO education. Includes installation manuals along with our vehicle database
- Vehicle database shows all cars we/members have installed on, with their MPG results and how acheived
| Organization | Stated role |
|---|---|
| Honda | Developing the electrolysis technology and conducting the component test. |
| Sierra Space | Mission manager, working with the Center for the Advancement of Science in Space (CASIS) and NASA on transport to the ISS aboard Dream Chaser. |
| Tec-Masters | Technical payload integrator responsible for payload integration and certification. |
How the ISS test relates to Honda’s other lunar work
The ISS component test is one part of a broader set of efforts, but the separate projects are at different stages:
| Project | What has been announced | What that establishes |
|---|---|---|
| ISS electrolysis test | Honda announced agreements in April 2025 for a microgravity test of a core component. | A planned component test; the reviewed official sources do not establish its launch or completion. |
| Honda-JAXA lunar-system research | Earlier research with the Japan Aerospace Exploration Agency concerned a circulative renewable-energy system for lunar living spaces and rover systems. | Research and development for a proposed lunar application, not an operating lunar installation. |
| Honda-Astrobotic feasibility study | On September 29, 2025, the companies announced a joint development agreement to study integrating Honda’s regenerative fuel-cell system with Astrobotic’s Vertical Solar Array Technology (VSAT) and LunaGrid service. | A study of possible integration for continuous lunar power, including during prolonged darkness; it does not establish completed hardware integration or an operational power service. |
Is this connected to Honda’s automotive fuel-cell plans?
No. Honda’s January 20, 2026, announcement that it would end production of its current GM joint-venture fuel-cell system before the end of 2026 concerns automotive fuel-cell production. Honda said it would use its independently developed next-generation fuel-cell system after that transition. That automotive change is separate from the space-oriented electrolysis component test.
Quick Recap
Best Value
Rank #4
- The Hydrogen fuel trolley uses zinc particles and food grade citric acid to synthesize hydrogen, and then uses the produced hydrogen and air to generate electricity to drive the trolley.
- During the experiment, please use 80℃ hot water for Combination reaction (if the water temperature is low, the amount of hydrogen and air pressure from the Combination reaction are insufficient, the fuel cell cannot be used for power generation), and then take off the plug of the vent pipe at the lower part of the fuel cell, release the gas in the rubber hose immediately, and then plug it back immediately, so that only pure hydrogen and air are in the fuel cell, so that the fuel cell can generate hydrogen air power.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
