A startup is testing a novel nuclear battery technology in orbit that could provide continuous power for satellites and lunar systems in environments where solar energy is not viable. The mission, conducted by City Labs, aims to validate a power source that relies on the radioactive decay of tritium, a hydrogen isotope, to generate electricity.
The technology, known as a betavoltaic battery, converts beta particles emitted by tritium into electrical current. Unlike traditional solar panels, which require direct sunlight to function, these batteries can operate in complete darkness, making them particularly suited for applications on the Moon, in deep space, or on the shadowed side of orbiting spacecraft.
City Labs has deployed its battery on a small satellite platform to test its performance under actual space conditions. The experiment will measure how the device holds up against the vacuum, temperature extremes, and radiation environment of low Earth orbit. Early results are expected to inform future designs for longer-duration missions.
The company has emphasized that tritium is a relatively safe radioisotope, with low-energy emissions that are easily shielded. The batteries are designed to last for decades without maintenance, offering a potential power solution for scientific instruments, communication relays, and other critical systems that must operate far from the Sun.
Interest in nuclear batteries has grown as space agencies and private companies plan extended missions to the Moon, Mars, and beyond. Solar power becomes less efficient as distance from the Sun increases, and it is unavailable during long lunar nights, which last about 14 Earth days. A reliable, compact power source could enable continuous operation of rovers, landers, and habitats.
City Labs is not the only organization exploring betavoltaic technology. Several research groups and startups have developed prototypes using different radioisotopes, but tritium is attractive because of its relatively short half-life of about 12.3 years, which provides a steady power output over a useful mission lifetime, and its low radiological hazard.
The current test follows years of laboratory development and ground-based validation. The company has previously demonstrated its battery technology in simulated space environments, but this orbital mission represents a critical step toward operational use. If successful, the batteries could be integrated into satellites and lunar payloads within a few years.
The mission also highlights a broader trend toward miniaturized power systems for small satellites. As spacecraft shrink in size and cost, there is a growing need for compact energy sources that do not rely on bulky solar arrays or heavy chemical batteries. Nuclear batteries offer a dense, long-lived alternative that could open new mission possibilities.
City Labs has not disclosed the exact power output of its current device, but betavoltaic cells typically generate microwatts to milliwatts, sufficient for low-power electronics such as sensors, memory chips, and timing circuits. For higher power demands, multiple cells can be stacked or combined with other energy sources.
The company is also exploring applications beyond space, including medical implants, remote sensors, and security devices where long battery life is critical. However, the immediate focus remains on space qualification, where the technology could first find a market.
Observers note that regulatory hurdles and public perception of nuclear devices in space remain challenges. City Labs has worked with U.S. regulators to ensure its batteries meet safety standards for launch and orbital operation. The company has also engaged with potential customers in the defense and commercial satellite sectors.
The test mission is expected to last several months, after which the company will analyze data to refine its designs. Success could position City Labs as a key supplier of nuclear batteries for the growing lunar economy and deep-space exploration initiatives.
