Energy transitions tend to presage changes in military power. Steam engines freed fleets from the vagaries of wind, oil unlocked ways to travel faster and farther, and digital power built the modern command network. The U.S. Army’s Janus program, which seeks to develop nuclear microreactors, could be similarly revolutionary – not because it introduces fundamentally new energy sources but because it fixes a fundamental vulnerability of contemporary warfare: dependence on electricity.
The Janus program is designed to break this dependency. By installing and deploying small, nuclear reactors able to run for years without resupply, the Army means to do nothing less than to build portable, powerful energy grids. If successful, Janus would be the most significant technological breakthrough since the adoption of oil.
To some degree, military power has always been bound by the energy system that supports it – whether wind, steam or fossil fuel. By the middle of the 20th century, increasingly large naval electrical loads and the need for mobility without refueling forced carriers and submarines to adopt nuclear propulsion; land bases, however, never followed suit because cheap fuel and a secure national grid made autonomous power unnecessary. Then came the digital age, which turned forward operating bases into miniature electrical grids. To manage this complexity, the U.S. consolidated the force around a single battlefield fuel, known as JP-8, simplifying logistics but tying nearly every system to the same energy chain.
Meanwhile, military power projection was hostage to a few fundamental constraints: A military can see only as far as its sensors can be powered. It can maneuver only as far as energy can be delivered, and it can sustain its commands only as long as electricity remains stable. When power depends on long supply lines or fragile infrastructure, strategy becomes defensive, bound to the terrain in which it operates. The rise of unmanned systems accelerated this trend as drone fleets and persistent surveillance necessitate continuous electrical loads on already strained base power.
Advances in nuclear miniaturization could free militaries from these constraints. Improvements in heat pipe cooling, passive safety, compact shielding and autonomous controls now mean that assets no longer have to be so closely tethered to industrial plants. The U.S. Department of Defense’s Project Pele has proved that microreactors can be built and run safely at a small scale. The Janus program aims to turn this proof of concept into a strategic reality.
Modern warfare burns extraordinary amounts of fuel just to keep bases powered. Studies of recent conflicts show that 50-75 percent of battlefield fuel was used to sustain base support loads – power generation, infrastructure, base services, etc. – rather than on maneuver or platform fuel. In recent U.S. wars, fuel and water accounted for roughly 70 percent of all logistics tonnage.
At home, major bases are tied to national grids that are increasingly seen as contested domains. Cyberattacks, substation sabotage and extreme weather failures can blind sensors, sever communications and halt targeting cycles throughout a theater. Project Janus addresses this by giving bases a hardened, independent power spine that functions even if the national grid is degraded.
The challenge is sharper overseas. Forward bases rely on host nation infrastructure and diesel systems that can be quickly taken offline under a kinetic attack or a cyberattack. A microreactor allows these bases to operate regardless of local infrastructure damage.
While all theaters will benefit from microreactors, the biggest changes will come in regions previously unusable for sustained operations. Because Janus is modular and rapidly transportable, it can be installed and integrated into a microgrid in days. Take the Asia Pacific, for example. The first and second island chains, which hem China in from the rest of the Pacific Ocean, lack the electrical infrastructure to host more than small teams or passive sensors. A transportable microreactor deliverable by air, land or sea could turn an austere airstrip into a functioning operational node with radar coverage, satellite communications, drone operations and a proper command post, creating persistent and survivable positions where none previously existed. Instead of being merely passable terrain, these islands would become strategically useful.
Naturally, other countries are pursuing independent energy systems. Russia operates small nuclear power units such as the Akademik Lomonosov floating plant and the RITM-class reactor to sustain remote Arctic sites. China is developing floating reactors and modular island power systems for militarized outposts in the South China Sea, though it has not fielded transportable land-based microreactors. The Janus program is unique in that it is the only effort aimed at a rapidly deployable, land-mobile reactor.
Microreactors are not without their own risks and constraints. They centralize power to one location, and a forced safe mode shutdown – whether triggered by sabotage, corrupted sensor data or a cyber intrusion – can temporarily remove a base’s primary power source. The reactors can be buried and hardened against concussive blasts and electromagnetic pulses, but their control systems are not immune to cyberattack. Cybersecurity architectures are being developed but remain a structural challenge for deployment.
Public opinion is also potentially obstructive. Nuclear systems face political resistance, regulatory scrutiny and allied concerns that slow deployment and limit the number of locations where reactors can be fielded. In many allied territories, political and regulatory barriers may prohibit deployment.
A final constraint is fuel and industrial capacity. Microreactors use high-assay low-enriched uranium (HALEU), enriched to 5-19.75 percent of the U-235 isotope. Russia remains the only commercial-scale supplier, while U.S. production is still small-batch and not expected to reach industrial levels until later this decade. Designs exist, but fabrication capacity and licensing timelines will determine how quickly Janus can expand beyond initial domestic sites. If U.S. HALEU production lags, Janus will become strategically capped regardless of technical performance. These limitations can shape deployment, not the underlying strategic direction. Put simply, the vulnerabilities of the current energy architecture now impose greater strategic costs than the risks of adopting a new one.
Despite these risks, the Janus program fundamentally changes the physical foundations of U.S. basing. The military can create, restore and sustain operational nodes in places that were previously untenable or easily disabled. It strengthens survivability, expands freedom of action and supports higher-tempo operations under modern contested conditions.
More broadly, Janus reflects a shift in how the U.S. thinks about continuity of operations. Domestic bases are no longer assumed secure. Mission assurance planning now treats the loss of external power and support systems as an expected condition rather than an exception. Overseas, dispersed operations create the same problem. Washington now relies on many small, widely separated sites in Europe and the Indo-Pacific that must provide continuous sensing and communication. These positions cannot easily be sustained by fuel convoys or host-nation utilities during conflict. Renewables and batteries support distributed sensing but cannot supply multi-megawatt, 24/7 baseload power under duress.
Janus-produced microreactors are slated to be used at domestic bases in 2028 to test performance and resilience. If successful, they will then be used at airfields, expeditionary nodes and select overseas sites. Even just a few self-powered nodes will facilitate sustained use of remote Indo-Pacific islands, faster recovery of European air bases after grid attacks and year-round footholds in the Arctic and the Caribbean.
As these reactors enter service, they will reshape force design. Air Force agile employment concepts will gain credibility, and Marine littoral regiments and Army dispersed formations can operate longer without resupply. Energy autonomy reduces the scale of logistics formations and increases the endurance of small, distributed units.
In time, microreactors will likely be adapted for civilian use. A rapidly deployable reactor will be useful in disaster recovery, small, remote towns, and critical infrastructure. If the reactors perform as intended, the U.S. will enter the 2030s with a posture fundamentally more resilient under contested conditions. If it fails, the U.S. will forfeit the only near-term pathway to harden bases against grid attacks, break fuel dependence and sustain distributed operations under modern strike conditions.
