A NASA Nuclear Reactor On The Moon? Bold Proposal Is Unfeasible By 2030 – Here’s Why

As reported in an exclusive by Politico, the announcement to fast-track plans for a nuclear reactor as a power source on the Moon is coming this week, necessitating questions about how realistic both the goal and time frame are. The Trump administration proposed a budget that would devastate NASA’s multiple science programs, and while it asked for more funding for human spaceflight in the short term, it would cancel the Space Launch System and Orion Spacecraft, making NASA exclusively reliant on private companies to get to the Moon. As yet, we don’t have one of those that won’t stop exploding.

The potential of a space nuclear reactor

Having a nuclear reactor on the Moon is not intrinsically a stupid or outlandish idea. Power generation is crucial for a permanent or semi-permanent settlement on our natural satellite. As nights last for 14 Earth days on the Moon, our solar options are limited. We could massively invest in batteries or place solar panels on the Peaks of Eternal Light. These areas, with a name right out of a fantasy novel, are outcrops near the lunar poles, where the Sun never sets.

However, the peaks are limited and very valuable real estate on the Moon, and there are not that many to go around. In a different geopolitical situation, international cooperation could allow a peaceful sharing of this resource. A nuclear reactor allows for decade-long continuous power generation, independent of sunlight availability or location. 

Another valuable piece of real estate on the Moon is the Crater of Eternal Darkness, also located at the poles, where sunshine never reaches the bottom and where water is trapped in the soil. Nuclear reactors could be an ideal power source in those locations. Nuclear fission power is not seen by experts as the be-all and end-all of power sources on the Moon (or maybe Mars), but it is being considered an important addition to what is possible.

One likely reason for the fast-track of the US’s plans is that just two months ago, China and Russia signed a strategic accord to build a nuclear reactor on the Moon, targeted to be up and running by 2036. However, from a geopolitical point of view, there is something standing in the way of any country doing so. Nobody can own territory in space, according to the 1967 Outer Space Treaty, but if you place a nuclear reactor on the surface of another world, you can still establish a safe zone that prevents access to others due to safety requirements.

The reality and complexities of a nuclear reactor in space

NASA has been looking at nuclear fission reactors for a while, with some important and intriguing developments. In January 2024, it wrapped up its first phase of the Fission Surface Power project, where several private companies showed that it is possible to create nuclear power sources that are safe, clean, and reliable. Three contracts were extended to gain more knowledge before the second phase, which was expected to start this year. The goal was to then develop a reactor that could be put on a launch pad by the early 2030s, be tested for one year, and then operated for nine.

According to Politico, Duffy wants a 60-day consultation to get a reactor on the Moon by 2030. A week might be a long time in politics, but five years is a very brief time in developing a new technology to operate i space. Even if we allow landing the nuclear reactor on December 31, 2030, the timing is really too short for something that must not have any faults if you want to operate it safely.

Previous reactor designs like the Kilopower Reactor Using Stirling Technology (KRUSTY) have shown to be robust. The current Fission Surface Power ideas are also interesting. They used uranium, which, as it decays, releases heat, and the heat is used to move a turbine. This is a Brayton converter, but currently, they waste a lot of heat, so the current designs aim to minimize that and increase efficiency.

Those designs aimed for a reactor that produces 40 kilowatts of energy, while Duffy is going to ask for 100 kilowatts. Originally, NASA specifications were for something no heavier than 6,000 kilograms (13,000 pounds) to fit on a launch vehicle. When it comes to space, mass is money, because it costs a lot to send something into space. And in this case, the reactor needs to be gently landed on the Moon, something that is not easy, as the many lunar missions in the last few years have found out.

Before we get to the transport, let’s focus on another issue: cooling. Reactors need to be cooled to avoid meltdown. The Russian-Chinese proposal still has not found a solution to that. On Earth, nuclear reactors use billions of liters of water, and while most of it never leaves the reactor, it is still a lot. There is water in those deep lunar craters, but just how much and how easy it is to get to it remains unknown. These proposed space reactors are much smaller than anything on Earth, so the cooling could be more manageable, but it is still a crucial aspect to consider.

For KRUSTY, which is much smaller than the expected design, producing a handful of kilowatts, the cooling is built into the reactor function. The uranium melts sodium in heat pipes, transferring the heat to a gas that moves a Stirling engine piston. It is possible to design different passive heat mechanisms, but the question is how they scale and how much material they need.

If it is material from Earth, like sodium for KRUSTY, this would make the reactor heavier and more expensive. If it is material from the Moon, the question is about what facilities are necessary to make it happen.

Fly Me To The Moon?  

The other issue is launch and landing. Currently, there is no working independent lunar lander that can get something safely to the Moon’s surface. One of the proposed lunar landers is SpaceX’s Starship; however, during its most recent test flights, it has not been able to demonstrate safe flight to space, exploding multiple times. It is unclear when it will reach the level of safety where you’d be happy to stuff it with a few hundred kilograms of uranium and let it fly overhead.

While a nuclear reactor proposal seems a feasible development for human lunar exploration, the date makes it unfeasible. Both Starship and Blue Origin’s Blue Moon lander are expected to be operational by 2030, and the companies involved in the Fission Surface Power project can probably have prototypes ready by that deadline, given their work over the last several years. Still, nothing can go wrong to make the deadline, and we feel that nuclear reactors are not one of those things you would want to rush to get out there.