Milestone for Zeno Power’s space nuclear battery

Earlier today, Zeno Power announced the completion of the final design review for its americium-241-fueled radioisotope power system (RPS), called Harmonia, which was developed for one of NASA's Tipping Point projects for Artemis.

The project will now begin the build and fabrication phase. The company plans to complete a terrestrial demonstration of the system in early 2027 and is aiming for flight qualification for lunar missions beginning in 2028.

Zeno was awarded $15 million by NASA for the project in 2023. Harmonia's radioisotope heater unit (RHU), now advanced to Technology Readiness Level 5, uses a Stirling convertor to generate electricity-technology that the company is now advancing to Technology Readiness Level 6. According to Zeno, Harmonia delivers 3.5 times the originally specified power output.

With the recent NASA announcement of the agency's pivot to making a moon base a near-term, primary focus, nuclear power sources are an essential component for providing heat and power for equipment and crews, especially at the lunar south pole where the long nights and frigid temperatures would limit mission length. NASA plans to use RHUs, radioisotope thermal generators, and fission surface power to help with the moon's harsh climate.

"Completing final design review for Harmonia is a critical milestone for NASA's Artemis program," said Lindsey Boles, chief product officer of Zeno Power. "Our design delivers the continuous power needed to transform lunar missions from two-week sprints into long-term operations. We're building the power infrastructure that could enable a permanent moon base."

Plutonium-238 has been the fuel of choice for radioisotope power units for space applications, but Am-241 has become an increasingly popular option that avoids the supply chain constraints of Pu-238 and, with its 430-year half-life, provides longevity for longer missions.

Zeno secured its Am-241 source last fall in a strategic agreement to with Orano, which would be recovering the isotope at its La Hague nuclear fuel recycling site in Normandy, France.

According to NASA's TechPort, Harmonia's interface is required to be compatible with an Intuitive Machines lander, and Blue Origin is responsible for the power system design and integration of the Stirling convertor into an RPS.