Earlier this month, a small satellite built by City Labs was launched to low Earth orbit aboard SpaceX’s Transporter-17 rideshare mission. The successful launch marked a milestone for commercial nuclear energy in space, potentially defining key safety and security norms and expectations for future nuclear-powered projects.
The BOHR satellite—short for Betavoltaic Orbital High-Reliability—was one of 81 payloads on the Falcon 9 mission from Vandenberg Space Force Base in California. BOHR is not carrying a reactor; its payload is a compact “nano-tritium” betavoltaic battery that converts beta particles (electrons or positrons) from the natural decay of tritium into electricity through a semiconductor. The nuclear battery is an experiment meant to demonstrate that small payloads can operate without sunlight. This capability could matter for deep-space missions, lunar night operations, and permanently shadowed regions of the Moon. For this flight, however, the satellite still relies on conventional solar panels to power its general operations.
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Although the BOHR spacecraft carries very little radioactive material, the approval process CityLabs followed set a regulatory precedent.
How is this different from the https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator that powers the Voyager space craft? Or is it just that it’s not NASA developing this version of it?
As I understand: RTG converts radiation into heat and then heat into electricity. Betavoltaics are like photovoltaics for beta radiation. And heat is generally a problem on a spacecraft so the less needs to be produced, the better.