For Space Nuclear Power, Go Big or Go Home

In “A Strategy for Building Space Nuclear Systems That Fly” (Issues, Fall 2025), Bhavya Lal and Roger M. Myers are right to bring up the importance of space nuclear power. The United States’ long-term national advantage is absolutely tied to remaining competitive in space nuclear power and propulsion—and their critical economic security and national security applications.

Lal and Myers correctly diagnose the issues. Their Manhattan project test is spot on. We will not see a successful space nuclear program without strategic urgency, adequate multiyear funding, and a single empowered leader.

That said, while a commercially driven project to produce 100 kilowatts of electricity on the Moon is an improvement over the previous, anemic 40 kW government-led program, it is hardly ambitious. The purpose of our Moon program is to enable industrial development, which requires megawatts, not kilowatts, of power. China and Russia are targeting more than 1,000 kW of electric power. High power is a requirement for propellant production on Mars. All plans for nuclear thermal and nuclear electric propulsion for fast transits to Mars require double- or triple-digit megawatts. For an administration willing to pursue a Golden Dome space shield to ward off nuclear attacks, 100 kW is hardly bold; it is timid and falls outside its political term.

Achieving an installed 100 kilowatts on the Moon by 2030 (or a Mars flyby as suggested in a leaked plan for NASA’s Project Athena) is a good five-year challenge (within this administration would show some urgency). But it makes sense only if it is part of a broader articulated (and resourced) national strategy to develop reactors capable of hundreds of megawatts.

Having the right vision is not technological overreach: It orients the near-term actions to ensure that the United States is on the right path to the right summit and not heading toward a strategic cul-de-sac. The demonstrator is not “the mission.” The mission is to equip the nation with a power advantage that necessarily is measured in the megawatts. That mission determines the magnitude, schedule, timeliness, and increments of working in space. We need not only an empowered leader but a legally constituted permanent empowered directorship with its own mission and funding line.

Let’s not be timid as a nation, and let’s keep our nuclear ambitions focused on the strategic competitions that matter: megawatts of power for an in-space industrial civilization.

Peter Garretson

Bhavya Lal and Roger Myers make a strong case for the conditions necessary to bring new US space nuclear power capabilities to reality. The United States has relied on nuclear power for deep space missions, but in the form of relatively simple radioisotope thermoelectric generators (e.g., as used on still-operating Mars rovers). The Soviet Union has deployed dozens of nuclear reactors to space and China is looking to Russia to provide a nuclear reactor for its International Lunar Research Station. In contrast, the United States has not been able to put a nuclear reactor into space for the past 60 years while starting and cancelling multiple efforts.

The gap in space nuclear power is not for lack of US interest, as Lal and Myers chronicle. For its part, the first Trump administration recognized that the successful development of space nuclear power for government purposes required a thriving commercial nuclear industry, technological advances, and a supportive (not obstructive) regulatory environment. Accordingly, the administration streamlined the approval processes for launching nuclear power sources, outlined a strategy and specific milestones for space nuclear power and propulsion, and specifically focused on small modular reactors for defense and space applications.

The second Trump administration has been similarly active. It has taken various actions aimed at, among other goals, promoting public-private partnerships, promoting US technology exports, speeding the approval of new reactor designs, speeding certification of emerging technologies, and addressing bottlenecks in workforce training, supply chains, and the fostering of domestic manufacturing. As one example of its ambitions, the administration in August 2025 issued a directive calling for using fission power to generate a minimum of 100 kilowatts of electric power on the Moon by 2030. Why might this effort succeed when past efforts have not? The first reason for optimism is the existence of a clear mission requirement for large-scale nuclear power on the Moon and Mars, in amounts necessary for a manned base and not just a single science mission or a technical demonstration. The second is that the NASA effort is part of a whole-of-government effort to revitalize the US nuclear power industry for economic, national security, and exploration purposes. Third, the effort is part of advancing a wide range of urgent US interests that have a good chance of securing sustainable, bipartisan support.

Certainly, the technical challenges to safely operate large fission surface power reactors on the Moon and Mars are great, but greater challenges are likely to be on Earth. The United States needs to attract, train, and retain a new generation of skilled nuclear engineers and technicians across government, industry, and academia. It needs to restore and strengthen specialized supply chains that have languished, and to overcome regulatory and bureaucratic hurdles that have ossified for decades. Can the United States do great things in space again? The urgency, funding, and leadership required for the space nuclear power effort will be a test of that question.

Scott Pace

Bhavya Lal and Roger M. Myers correctly identify issues that have held the United States back from developing space nuclear systems, which will be essential to permanent and sustained presence on the Moon, Mars, and the future of humanity in the solar system.

With NASA taking the step of baselining nuclear power for Mars, this may be the mission pull that will drive the government to solve some or all of those issues. Lal and Myers make an interesting point that the White House could take a leadership role given the diffuse responsibilities across multiple agencies. I certainly agree with the authors that without such “Manhattan Project” conditions and supportive “scaffolding” inside the government, commercial efforts alone cannot succeed.

One challenge not mentioned is that NASA does not have sole authority over deciding how much funding will be allocated to existing programs, surprising as that may seem. Both Congress and the executive branch’s Office of Management and Budget must be willing to fund such systems even when the technical policy community is clearly behind them. The federal government system of small across-the-board increases in any agency’s budget does not do well with major new funding initiatives, and there is resistance on the part of industry and Congress to shut down existing efforts to fund new ones. A White House leadership role may be able to help solve that.

Of course, the question will be if a White House leadership role would be sustained across administrations. An alternate solution could be to clarify roles and responsibilities among agencies statutorily to ensure a single agency has the clear leadership role. This of course brings its own challenges. As Lal and Myers argue, the directive from Sean Duffy, the US secretary of transportation and NASA’s acting administrator, is indeed a chance to take a bold new direction in this critical area.

Pam Melroy