City Labs Seeks FAA Approval for 10 Million Curies After 20-Curie Space Debut

City Labs will ask the Federal Aviation Administration in December to approve up to 10 million curies of tritium per mission, a sharp leap from the 20 curies it flew on its first nuclear-powered satellite. Chief executive Peter Cabauy outlined the plan Thursday in a technical brief at Silicon Valley Space Week's MilSat Symposium, framing it as a challenge to plutonium heat sources used today.

The push follows City Labs' BOHR mission, which the company calls the first commercial nuclear satellite. BOHR launched in July under an FAA payload authorization permitting up to 10,000 curies. "We launched only 20 curies because it was our demonstration," Cabauy said. The regulatory path opened in 2019, when National Security Presidential Memorandum 20 allowed commercial companies to launch nuclear radioisotopes without a presidential signature for each mission. City Labs was the first to use it, which Cabauy credited to 20 years of work making its betavoltaic batteries safe enough for a Nuclear Regulatory Commission general license.

"We're submitting right now to the FAA an application for 10 million curies. That's 300 watts thermal," Cabauy said. The company is working with Sandia National Laboratories, which runs the nuclear safety analysis, "so that we can compete and supplement what's being done with plutonium heat sources today." City Labs talks with the FAA every two weeks and expects to make the formal submission in December, aiming for approval "sometime next year, summer." A slide listed a 2027 licensing target of up to 10 million curies per mission.

Before that, City Labs plans to fly a tritium heater next year under its existing authorization, which covers a class of devices rather than a single launch. "It's not like the old days where you just get approval to launch one," Cabauy said. "We approved a class." The company has filed an amendment to add its heat sources to that class, which he hopes to have by January. Each heater unit holds 1,000 curies, and customers can combine them: one gives about 30 milliwatts of heat, and 30 together give a watt. City Labs recently posted live telemetry data from BOHR on its website, showing voltage, current and sensor readings.

Cabauy's case rests on where solar power runs out. "Nuclear should be used whenever you have a situation where solar can't be used," he said. Commercial lunar landers last about 14 days. "Then the night comes in, and $400 million is lost," he said. "We need nuclear on the Moon." Keeping a lander warm through the night with batteries is costly, he said. "For every watt of heat, it's five kilograms. It's a misuse of mass and volume." A tritium heater, he said, can do the same job with a tiny fraction of that mass. He argued plutonium cannot fill the gap at scale, noting it is difficult to produce and that nuclear-powered launches have averaged about one every five years. With tritium, the FAA is letting City Labs build small modules placed only where heat is needed, such as a single chip or battery. "This will be able to dial in in small increments and do something the plutonium can never do," he said.

City Labs expects the heater class amendment by January so the heater can fly next year, with the 10-million-curie submission due in December and approval targeted for summer 2027.