In our latest episode of Lexicon, we sat down with Peter Cabauy, CEO and founder of City Labs, to explore why power, rather than propulsion, could become the defining technology of the next era of space exploration.
Cabauy explains how the Moon’s extreme environment, particularly its 14-day-long nights and brutally cold temperatures, presents a major challenge for long-term lunar operations, and why nuclear micropower could be the key to keeping rovers, equipment, and future lunar outposts running.
Also, subscribe to IE+ for premium insights and exclusive content!
Trickle, not a flood
“The moon is a very inhospitable environment,” Cabauy told us. “Your rover is only going to last 14 days because that’s the length of the lunar day,” he added.
After that comes the lunar night, another 14 Earth days of darkness where temperatures plunge to levels colder than liquid nitrogen. “We’ve all seen what happens when you drop a flower inside liquid nitrogen and hit it with a hammer,” he said. “Imagine trying to make a rover survive in that type of environment,” he added.
That, he explained, is where nuclear micropower comes in. Unlike conventional nuclear reactors, City Labs develops microscopic power sources that generate electricity and heat through the natural decay of tritium.
“The easiest visual is a solar cell,” Cabauy said. “Instead of receiving light, we receive beta radiation.”
Those electrons generate a tiny but continuous electrical current. While the output is measured in nanowatts or microwatts rather than kilowatts, the systems never need recharging and continue operating for decades.
“The real power is that it’s continuous,” he said. “It works under extreme temperatures.” He was quick to stress that these devices were never intended to replace lithium batteries.
“If you can use a lithium battery for what you need to do, please do it,” he said. “This is for what you can’t possibly replace.” Instead, they are designed for environments where replacing a battery is impossible, prohibitively expensive, or life-threatening.
A pacemaker was one example. “Do you really want to do extra operations?” he said.
Powering the lunar economy
Cabauy believes reliable long-duration power would become one of the key enabling technologies behind a permanent human presence on the Moon. “Nuclear micropower is what’s going to enable that lunar economy,” he said.
Rather than relying on miles of copper cable or solar panels that become useless during the lunar night, he envisages thousands, or even millions, of autonomous sensors scattered across the lunar surface.
“You can drop thousands and hundreds of thousands of these devices into permanently shadowed craters,” he said.
Those sensors could provide navigation, communications, environmental monitoring, and scientific data while operating continuously in places where sunlight never reaches. “Think of millions of these tritium-powered small devices on the lunar surface,” he said. “This is where it’s going.”
He also believes they could support future missions to Mars, heliocentric spacecraft and new generations of miniature satellites.
“We’re excited about what we can’t think about today,” he said. “Other engineers are going to come up with those ideas.”
From peanuts to tritium
Growing up, one of his heroes was George Washington Carver, the scientist famous for finding hundreds of applications for peanuts. “George Washington Carver tried to find a thousand uses for peanuts,” Cabauy said. “At City Labs, we try to find a thousand uses for tritium.”
That mindset, he explained, shaped everything the company he would eventually build now pursues. He explained that tritium is an ideal radioisotope because it was relatively benign, already had an established regulatory framework, and benefited from a reliable supply chain.
“It wasn’t an accident that we chose tritium,” he said. Today, City Labs uses it for beta-voltaic batteries, heat sources, and future propulsion concepts.
Engineering was only half the battle
Despite spending two decades developing the technology, Cabauy argued the engineering challenge had only been part of the story. “The engineering was tough,” he said. “But I would advocate that regulatory is equally as tough.”
Much of the company’s innovation focused not only on making the devices work, but making them safe enough to fit within existing regulatory frameworks. “We found ourselves engineering towards the regulatory as well as the commercial scale-up,” he said.
That work ultimately led to what he described as a significant milestone.
“We’re crossing the nuclear space threshold as the first to be able to commercially launch a nuclear device.”
The year everything nearly ended
Perhaps the most compelling part of the conversation had little to do with nuclear technology. Cabauy shared some candid information about the darkest period in the company’s history.
“That was a bad year,” he said, recalling 2017 when City Labs came close to shutting down. “I told my wife, ‘I quit. I just can’t do this,” he said.
The following morning brought a different realisation. “I said, ‘Well… I can’t quit. I just don’t know how.'”
The company lacked the money even to decommission its facilities, leaving little choice but to keep turning up. What changed, he said, was his mindset.
“When opportunities came, I just said yes.”
Instead of analysing every decision as a physicist, he returned to the curiosity that had driven him as a child. “I decided to go back to the childhood inventor,” he told us.
Unexpectedly, people began offering help. “I started realising there’s more than just paying people to work,” he said. “There’s also the vision of where we’re going.”
That shift proved transformational. “People would offer me help,” he said. “All I had to do was say yes.”
Soon afterwards, contracts began arriving from companies including Lockheed Martin Space and medical device manufacturers, setting City Labs on the path it follows today.
Looking beyond space
Although lunar exploration dominated much of the discussion, Cabauy believes that nuclear micropower would also find applications much closer to home. He highlighted downhole oil and gas monitoring, industrial sensors and next-generation medical implants.
One area he found particularly exciting was leadless pacemakers. “If you want to reduce it down to the size of a grain of rice, nuclear is probably going to be it,” he said.
He also pointed to research exploring tiny tritium-powered light sources designed to help prevent diabetic retinopathy, potentially slowing vision loss in patients.
A commercial nuclear space age
Looking ahead, Cabauy remains focused on City Labs’ upcoming milestones, including the launch of its Bohr satellite demonstration mission. “We’re opening up this nuclear space age,” he said.
Ultimately, however, his ambitions extended beyond City Labs itself.
“I want City Labs to lead the way in terms of nuclear micropower,” he said. “But it’s not just us. It’s many others using this type of technology to find applications and use cases where our imagination isn’t enough today to know what they will be,” he told us.