Startup testing nuclear battery technology in orbit
A Florida startup has launched what it says is the first commercial demonstration of a nuclear-powered satellite technology, testing a power source that could allow future spacecraft and autonomous sensors to operate for years without relying exclusively on solar panels or conventional batteries.
City Labs said its BOHR (Betavoltaic Orbital High-Reliability) cubesat lifted off July 7 aboard SpaceX's Transporter-17 rideshare mission, marking the first in-orbit demonstration of the company's NanoTritium betavoltaic power system. The mission is designed to determine whether the technology can generate electricity independently of sunlight over extended periods, potentially expanding the range of missions that can operate in deep space, permanently shadowed regions of the moon and other environments where solar power is limited.
The demonstration, partially funded by NASA and Pentagon contracts, reflects government interest in alternative space power systems to keep satellites and distributed sensor networks operating longer in contested environments. While radioisotope power has been used for decades on NASA's deep-space probes, commercial companies have largely stayed out of the field because of technical, regulatory and safety hurdles.
City Labs specializes in betavoltaic batteries powered by tritium, a radioactive isotope of hydrogen. The devices convert the energy released through radioactive decay directly into small amounts of electricity. The output is measured in microwatts rather than watts, making the technology unsuitable for powering an entire satellite but potentially valuable for low-power electronics that must operate continuously for years.
The BOHR spacecraft itself is not powered entirely by nuclear technology. The cubesat relies on conventional solar arrays to operate the satellite bus, while the NanoTritium system independently powers the payload being evaluated. The objective is to validate the betavoltaic power source in orbit rather than replace the spacecraft's primary electrical system.
City Labs says BOHR represents the first commercial nuclear mission to use the Federal Aviation Administration's launch approval process established under National Security Presidential Memorandum-20, which created a regulatory framework for launching spacecraft carrying radioactive materials.
The company said its tritium-based power systems operate at extremely low radiation levels and are engineered for safe handling, transportation and integration with commercial launch vehicles.
A company spokesperson said the BOHR mission builds on years of private investment alongside support from the Pentagon's Operational Energy Innovation Directorate through its Operational Energy Capability Improvement Fund, as well as Small Business Innovation Research contracts with the Air Force Research Laboratory, AFWERX, NASA and SpaceWERX.
Pursuing commercial nuclear micropower systems
City Labs said it plans to launch an in-orbit demonstration of a tritium-powered Radioisotope Heater Unit, or RHU, in 2027 before moving toward operational systems designed to support long-duration missions on the lunar surface.
Unlike BOHR, which converts radioactive decay into electricity, an RHU generates heat. Such devices are used to keep spacecraft components, batteries and scientific instruments from freezing during long periods without sunlight, such as the two-week lunar night or inside permanently shadowed craters near the moon's poles. NASA has long relied on plutonium-powered RHUs for planetary exploration missions, while City Labs is pursuing a commercial alternative based on tritium.
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