Why on Earth would NASA build a nuclear reactor on the Moon?
"I have no idea why this is getting so much play," Professor Bhavya Lal tells me over the phone, with a hint of exasperation in her voice. Lal's response makes sense once you understand the arc of her career; she has spent much of her professional life thinking about how the US should use nuclear power to explore space. At NASA, she served as the acting chief technologist, and was awarded the agency's Distinguished Service Medal. Among her other qualifications, she also testified before Congress on the subject of nuclear propulsion, and even helped rewrite the rules governing launches involving radioactive materials.
Most recently, she wrote a paper titled Weighing the Future: Strategic Options for US Space Nuclear Leadership where she and her co-author, Dr. Roger Myers, examine the past failures of US policy as it relates to nuclear power in space and argue the country should test a small nuclear system on the Moon by 2030. The way Casey Dreier, chief of space policy at The Planetary Society — a nonprofit that advocates for the exploration and study of space — tells it, many aspects of Secretary Duffy's plan are "pretty much straight out" of that report.
Lal is more modest and describes the directive Duffy issued as "accelerating ongoing work" at NASA. According to her, the agency has been "funding [space] fission power for years," adding that the only new thing here is that there's a date. "We've done this for more than 60 years," she tells me, and if NASA ends up delivering on Duffy's plan, it wouldn't even be the first nuclear reactor the US has sent into space. That distinction goes to SNAP-10A in 1965.
The reason the US has spent decades exploring space-capable nuclear reactors is simple. "You can get massive amounts of power from very little mass," explains Nick Touran, reactor physicist, nuclear advocate and the founder of What is Nuclear . And for launches to space, keeping payload amounts low is critical.
Just how much power are we talking about? "When fully fissioned, a softball-sized chunk of Uranium-235 offers as much energy as a freight train full of coal," says Dr. Lal. Combined with the limitations of solar power, particularly the farther a spacecraft travels away from the sun, nuclear is a game changer. An artist concept of a fission power system on the lunar surface (NASA)
Dr. Lal points to the New Horizons probe as an example. In 2015, the spacecraft flew past Pluto, in the process capturing stunning photos of the dwarf planet . If you followed the mission closely, you may remember New Horizons didn't make a stop at Pluto. The reason for that is it didn't have enough power to enter orbit. "We had about 200 watts on New Horizons. That's basically two light bulbs worth of power," said Dr. Lal. It subsequently took New Horizons 16 months to send all of the 50-plus gigabytes of data it captured back to Earth. Had the probe had a 20-kilowatt microreactor, Dr. Lal says it could have streamed that data in real-time, on top of entering orbit and operating all of its instruments continuously.
When it comes to the Moon, nuclear would be transformational. On our only natural satellite, nights last 14 Earth days, and there are craters that never see any sunlight. Solar energy could power a permanent NASA outpost on the Moon, but not without a "huge" number of batteries to bridge the two-week gap in power generation, and those batteries would need to be ferried from Earth.
"At some point, we will want to do industrial-scale work on the Moon. Even if we want to do 3D printing, it requires hundreds of kilowatts of power – if not more," said Dr. Lal. "If you're going to do any kind of commercial activity on the Moon, we need more than solar can provide."
On Mars, meanwhile, nuclear power would be absolutely essential. The Red Planet is home to dust storms that can last weeks or months, and cover entire continents. In those conditions, solar power is unreliable. In fact, when NASA finally ended Opportunity's nearly 15-year mission on Mars, it was a planet-wide dust storm that left the rover inoperable.
As such, if the US wants to establish a permanent presence on Mars, Dr. Lal argues it would make the most sense to perfect the necessary reactor technology on the Moon. "We don't want our first-ever nuclear reactor operating on Mars. We want to try it out on the Moon first. And that is what I think NASA is trying to do."
Of course, there are many technical hurdles NASA will need to overcome before any of this is anywhere close to reality. Surprisingly, the most straightforward problem might be finding a 100-kilowatt microreactor. Right now, there's no company in the US producing microreactors. Atomics International and North American Aviation, the companies that built SNAP-10A, went defunct decades ago. NASA and NNSA engineers lower the wall of the vacuum chamber around KRUSTY system. (Los Alamos National Laboratory)
"There are many that are in development, but almost none that are even in the prototype stage," said Touran. As he explains, that's an important detail; most nuclear reactors don't work at all when they're first turned on. "It takes a few iterations to get a reactor up to a level where it's operable, reliable and cost effective," he said.
The good news is Touran believes there's more than enough time for either NASA or a private company to build a working reactor for the project. "I think we're in a great spot to take a good swing at this by 2030," said Touran. In 2018, NASA and the Department of Energy demoed KRUSTY , a lightweight, 10-kilowatt fission system. "That was one of the only newish reactors we've turned on in many decades, and it was done on a shoestring budget," he said.
In the end, deploying a reactor on the Moon may prove more difficult than building one. Based on some rough math done by Dr. Myers, a 100-kilowatt reactor would weigh between 10 to 15 metric tons, meaning no current commercial rocket could carry it to space. NASA will also need to find a way to fit the reactor's radiator inside a rocket. Unfolded, the component will be about the size of a basketball court.
According to Dr. Lal, the 2030 timeline for the project is likely based on the assumption Starship will be ready to fly by then. But Elon Musk's super heavy-lift rocket has had a bad 2025. Of the three test flights SpaceX has attempted this year, two ended in the spacecraft exploding. One of those saw Starship go up in flames during what should have been a routine ground test . SpaceX's Starship as seen during its eighth test flight (Reuters)
If Starship isn't ready by 2030, NASA could conceivably fly the reactor separately from all the other components needed to make a functioning power system, but according to Lal, "that comes with its own set of challenges." Primarily, the agency doesn't have a great way of assembling such a complex system autonomously. In any case, Starship is at least a tangible work in progress. The same can't be said for the lander that would be needed to bring the reactor to the surface of the Moon. In 2021, NASA contracted SpaceX to build a lander for the Artemis missions, but the latest update the two shared on the spacecraft was a pair of 3D renderings. Similarly, Blue Origin's Blue Moon lander has yet to fly, despite promises it could make its first trip to the Moon as early as this spring or summer.
Another question mark hangs over the entire project. As of the end of July, NASA is on track to lose approximately 4,000 employees who have agreed to leave the agency through either early retirement, a voluntary separation or a deferred resignation — all as part of the Trump administration's broader efforts to trim the number of workers across the entire federal government. All told, NASA is on track to lose about a fifth of its workforce, and morale at the agency is at an all-time low . Even with the Department of Energy and private industry providing support, there's good reason to believe the reductions will affect NASA's ability to deliver the project on time.
"The contradiction inherent in this proposal is that the White House is directing NASA to do the two most ambitious and difficult projects any space program can do, which is to send humans to the Moon and Mars, but to do so with a resource level and workforce equivalent to what the agency had before the first humans went to space in 1961," said Dreier.
A NASA spokesperson declined to share specifics on the reductions — including the number of employees set to leave the Glenn Research Center , the facility that built the KRUSTY reactor, and where much of the agency's nuclear engineering talent is concentrated. "As more official information becomes available, we anticipate answering more of your questions," the spokesperson said.
"I wish there was some inventory of the 4,000 people who left. What gaps are left? We have no idea if the departures were systematic," said Dr. Lal. "NASA has not been open or transparent about what types of employees have taken the deferred resignation program, where those skills are and where they're departing from," Drier added. "Nuclear engineering is not a common field for most people. [The reductions] certainly can't help." Still, both Lal and Touran believe the involvement of the Department of Energy is likely to swing things in NASA's favor.
In a statement NASA shared with Engadget, Secretary Duffy downplayed the workforce concerns. 'NASA remains committed to our mission, even as we work within a more prioritized budget and changes with our workforce. NASA retains a strong bench of talent. I am confident that our exceptional team remains capable of executing upon my directives safely and in a timely manner and will continue to carry our work forward," he said. "We will continue to ensure America continues to lead in space exploration, advancing progress on key goals including returning Americans to the Moon and planting the Stars and Stripes on Mars, as we usher in the Golden Age of American innovation.'
In their report, Lal and Myers estimate it would cost about $800 million annually for five years to build and deploy a nuclear reactor on the Moon. Even if DoE support can prevent NASA's staffing cuts from kneecapping the project, its feasibility will hinge on if the Trump administration ponies up the cash to execute on its own bold claims.
Have a tip for Igor? You can reach him by email , on Bluesky or send a message to @Kodachrome.72 to chat confidentially on Signal.
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
The Hill
10 hours ago
- The Hill
Critics shouldn't block NASA's nuclear path to a moon base
Sean Duffy, NASA's interim administrator, proved that the U.S. is serious about establishing a lunar base when he announced the deployment of a 100-kilowatt nuclear reactor on the moon by 2030. The idea, although a sound one, is not without its critics. The announcement that the first element of a lunar base will be a nuclear reactor was logical. Nuclear power, unlike solar, is available 24/7 and thus does not require backup batteries during periods when the sun is not available. That the reactor is first means that every other element of the lunar base can be hooked up and powered up immediately. As NPR notes, a 100-kilowatt reactor on Earth would be able to power 70 to 80 private homes in the United States, so it could power a decent-sized lunar base. It would have to withstand the extremes of heat and cold on the moon, not to mention the possibility of moonquakes and meteor strikes. Instead of water to cool it, the reactor would simply radiate the heat it creates into space. The cost would be about $3 billion. Space lawyer Michelle Hanlon describes some of the legal aspects of placing a nuclear reactor on the moon, especially in context of the space race with China. While the Outer Space Treaty prohibits claims of national sovereignty on the moon, the establishment of a nuclear reactor, especially with a lunar base attached to it, grants the nation-state that does it some measure of control over the surrounding territory. Its Article IX requires that states act 'with due regard to the corresponding interests of all other States Parties to the Treaty.' The practical effect of the Article IX provision is that the first country to establish a lunar base on the moon's south pole would be able to claim control over some prime real estate, important where ice mining is likely to be an essential enterprise. Duffy is therefore correct that the U.S. and its allies should be first with a nuclear reactor and a lunar base before China can establish its own and thus exert control. The idea of a nuclear-powered lunar base is not without its critics. For example, a CBS News host opined that colonizing the moon was akin to the colonization of native peoples on Earth by European powers. Celebrity astrophysicist Neil deGrasse Tyson set him straight by pointing out that no native peoples exist on the moon or anywhere else in the solar system beyond Earth. The exchange elicited eyerolling on the Fox News show 'The Five.' But even there, some griping occurred. Dana Perino, who used to work for President George W. Bush, expressed considerable ennui about the whole concept of space travel. From the perspective of someone who has seen a space shuttle launch in person and watched men walk on the moon live on television, the attitude seems to be bizarre and dispiriting. Tyrus, the former wrestler turned social and political commentator, trotted out the 'let's solve problems on Earth before we go into space' trope that has been around since the beginning of the space age. The obvious answer has always been, 'Do both.' Ross Marchand, writing for Real Clear Science, noted the $37 trillion national debt and then claimed that building a lunar base would be just too expensive. He undermined his argument by comparing the 100-kilowatt lunar nuclear power plant to the 1-gigawatt reactors that exist on Earth and cost $10 billion to build (largely because of permitting and environmental regulation problems). Then he increased the estimated cost by a factor of 10 'or more.' Although NASA projects often do suffer cost overruns, $3 billion to $100 billion would be a little much, even for the space agency with its history of inefficiency. Marchand also trotted out the 'robots can explore space cheaper and better than humans' claim that was soundly debunked by the late, great lunar geologist Paul Spudis. In fact, returning to the moon and going on to Mars also polls well and has bipartisan political support, even it still has its critics. No great endeavor ever undertaken since the beginning of civilization has not had people saying it can't or shouldn't be done. The International Space Station, for example, drew fierce opposition and was almost cancelled more than once. The orbiting space laboratory is currently churning out a stream of scientific discoveries and technological innovations, confounding its early critics, who are long since forgotten. The lunar base and even Elon Musk's planned Mars colony will undergo a similar process. Future generations will find it difficult to imagine a universe where humans just occupied one world. Mark R. Whittington, who writes frequently about space policy, has published a political study of space exploration entitled ' Why is It So Hard to Go Back to the Moon? ' as well as ' The Moon, Mars and Beyond,' and, most recently,' Why is America Going Back to the Moon? ' He blogs at Curmudgeons Corner.
Wall Street Journal
10 hours ago
- Wall Street Journal
Fuel Fill-Ups in Space? Musk and Bezos Are Working on It
Elon Musk and Jeff Bezos are trying to figure out how to pump gas in space. The billionaire space rivals are working on ambitious missions to the moon or Mars, and a crucial design element for each venture is using spacecraft that take on additional fuel while orbiting Earth. Vehicles that could grab propellants in orbit would be less weighed down at liftoff, letting planners design missions to travel farther from Earth with more cargo, scientific gear or crew members, advocates say.
Yahoo
10 hours ago
- Yahoo
Astronomers Say They've Finally Solved the 'Little Red Dots' Mystery
When the James Webb Space Telescope first came online in 2022, it immediately spotted something astronomers had never seen before: "little red dots" peppering the ancient expanse of deep space, originating from around when the universe was just one billion years old. Ever since, we've struggled to explain what these faint signals could be. The prevailing theory is that they're some kind of extremely compact galaxy. But at only two percent of the diameter of the Milky Way, the distribution of stars would have to be impossibly dense, perhaps more so than our current laws of physics allow. They're also too faint to be produced by a quasar, a type of supermassive black hole that is actively devouring matter, which it causes to heat up and glow. Moreover, the black holes would be "overmassive" for such a small galaxy, scientists argue. Now, famed Harvard astronomer Avi Loeb (or infamous, depending on how you view his speculative theories regarding aliens) and his colleague Fabio Pacucci believe they have an answer. In a new study published in the Astrophysical Journal Letters, the pair reinforce the idea that the family of red oddities are, in fact, galaxies — but are unusually tiny because they haven't started spinning up to speed yet. It's a hypothesis rooted in one of the leading theories for galaxy formation, which holds that these structures form in "halos" of dark matter, the invisible substance thought to account for 85 percent of all mass in the cosmos. While we can't see or interact with dark matter, it does exert a significant gravitational influence, which explains how the largest structures in the cosmos came together and took shape. In the study, the astronomers propose that the diminutive galaxies formed in halos that just so happened to be among the slowest spinning in the cosmos, with 99 percent of halos spinning faster. The idea, in principle, is simple. If you held out a piece of rope in one hand and started spinning in place, the rope would stretch out and reach farther. But if you slowed down, the rope would slump to the ground. This hypothesis would explain why we're only seeing the dots at such a nascent period of the universe. Over time, the halos would inevitably speed up, and their constituent galaxies would expand. "Dark matter halos are characterized by a rotational velocity: some of them spin very slowly, and others spin more rapidly," Loeb said in a statement about the work. "We showed that if you assume the little red dots are typically in the first percentile of the spin distribution of dark matter halos, then you explain all their observational properties." It's a compelling theory — but it's not the only game in town. Recently, two teams of astronomers found clues that what we're witnessing may actually be an entirely new class of cosmic object: "black hole stars." Their work suggests the glowing dots are an active supermassive black hole surrounded by a vast and thick shell of gas. The intense radiation of the black hole heats up the shell, which absorbs most of the emissions, dimming the light to an outside observer. In many ways, it resembles a star blown up to epic proportions — except, instead of nuclear fusion powering the center, there's a voracious black hole churning through matter. Loeb and Pacucci's theory doesn't address whether these slow-spinning galaxies have a black hole at their center, but suggests that they could form one. "Low-spin halos tend to concentrate mass in the center, which makes it easier for a black hole to accrete matter or for stars to form rapidly," Pacucci said in the statement. The luminous red dots, he added, "might help us understand how the first black holes formed and co-evolved with galaxies in the early universe." More on space: Astronomers in Awe of Terrifying "Eye of Sauron" That's Pointed Straight at Earth Solve the daily Crossword
