Zeno Power is NASA’s Choice for Leading Radioisotope Power System Development

By Sophia Francise

July 27, 2023

NASA has announced that a team led by Zeno Power has been awarded a $15 million Tipping Point award to develop an americium-241 (Am-241) radioisotope Stirling generator (RSG) for lunar surface missions.

The award targets the creation of a radioisotope Stirling generator (RSG), which could allow lunar assets to function and live during lunar night and in permanently dark regions of the Moon.

Zeno Power which is a developer of commercial radioisotope power systems (RPS) and the leader of the Harmonia team, which is developing the program is among the 11 American companies selected by NASA to develop technologies for moon and space exploration.

Other participants in the team include Blue Origin, Intuitive Machines Inc., Sunpower Inc., the University of Dayton Research Institute, NASA Glenn Research Center, and NASA Marshall Flight Center.

“Zeno is excited to work with these industry leaders to bring both americium-241 and Stirling conversion technologies to the lunar surface for the first time,” said he Co-Founder and CEO of Zeno Power, Tyler Bernstein.

What Does Project Harmonia Entail?

Due to the harsh conditions in these habitats, operations during the two-week lunar night and in persistently shadowed regions (PSRs) are difficult

“Project Harmonia will provide the technology to transform the Moon from a location darkened by night and shadow to one enlightened by science and exploration, ultimately for the good of the nation and humankind,” said Bernstein.

An RPS is a portable power source that transforms heat produced by radioisotope decay into a continuous flow of clean energy. 

Traditionally, plutonium-238 from the US Department of Energy has been used to power RPSs for space-related purposes, with a fuel supply stream large enough to power NASA’s flagship missions. 

Zeno’s new design offers more fuel possibilities by utilizing alternate radioisotopes that are now designated as nuclear waste, employing materials science and advancements in nuclear fuel manufacture.  

Americium-241, a long-lived isotope with advantageous thermal and radiation properties, can support the plutonium-238-based RPSs currently in use and enable mission classes that have not yet been pursued.1

Collectively, Project Harmonia, through NASA’s Tipping Point program, is working to enable lunar assets to live and function during the lunar night.

Zeno and Blue Origin will work with NASA Glenn Research Centre to scale up and improve the integration of Stirling converters into a unique RSG architecture.

Compared to older radioisotope power systems, the improved RSG will increase system efficiency thrice.

The RSG developed under this project will increase mission durations from two weeks to several years and make exploring PSRs near the lunar south pole possible. 

The objective of Harmonia is to create flight-ready technology for a lunar surface demonstration in 2027.


  1. Zeno Power, ‘NASA Selects Zeno to Lead Team to Develop Radioisotope Power System for Lunar Applications’, 25 July 2023, https://mcusercontent.com/bacd6ac1253081e0d16d76294/files/af5fc9d1-b44c-659c-4af0-5ddef086cceb/Zeno_Tipping_Point_PR_FINAL.pdf[]