SpaceX Launched the World’s First Nuclear-Powered Satellite

The world’s first nuclear-powered satellite is now orbiting Earth, thanks to SpaceX’s launch on Tuesday of a Falcon 9 rocket. The Betavoltaic Orbital High-Reliability (BOHR) satellite is designed as a proof of concept demonstrating that commercial nuclear power can operate effectively in space, while also leveraging traditional solar power for its main operations.

Nuclear-powered spacecraft have been a staple of deep space missions for decades. The Voyager 1 and Voyager 2 missions were famously powered by three radioisotope thermoelectric generators that use decaying plutonium to generate electricity. The BOHR power system is far, far smaller, but the developers at City Labs believe it can easily be scaled up to potentially support missions within shadowed lunar craters and into the solar system beyond.

Credit: City Labs

The BOHR uses a proprietary “NanoTritium” betavoltaic micropower source. Where spacecraft like Voyager 1 and 2 use the excess heat shed by plutonium to power the craft, the BOHR harnesses the beta particles emitted by the radioactive decay of tritium, converting that into electricity. It’s only enough to prove the concept is viable—not enough to power anything of substance, which is why solar power is also involved. But if it works, it can work again, is City Labs’ argument. And perhaps it could work on a grander scale.

One reason City Labs is pushing for the use of tritium in its designs over more traditional nuclear materials like plutonium is that its radiation is limited, making it much safer for humans to work around and shield against. That makes handling it easier, as well as loading it onto spacecraft and maintaining the power source.

A major downside, though, is the relative expense of tritium. It can cost tens of thousands of dollars per gram, with only about 20kg produced per year. Scaling up satellites and other spacecraft with this energy source could prove prohibitively expensive and create long-term supply bottlenecks.

Still, this latest launch was approved by the FAA, highlighting the US administration’s keenness to explore alternative fuel sources. As such, City Labs’ spacecraft could pave the way for future nuclear-powered launches using tritium or other unconventional materials.