Fusion energy companies are increasingly turning to defense contracts to help accelerate their development cycles. As venture capital slows in climate tech, startups that once focused solely on producing grid-scale clean power are also exploring military and national security applications.
Why Defense?
Traditionally, fusion research has patriarchs in national security labs, where scientists sought peaceful uses for the same physics underlying thermonuclear weapons. Though civilian energy goals remain central, budgetary pressures and the long path to commercialization are driving fusion startups to diversify. With climate tech funding plateauing, defense dollars offer both financial lifelines and acceleration paths for dual-purpose technologies.
One key driver is laser-based fusion. These systems have obvious civilian uses—power generation—but also strong appeal for defense applications like directed energy weapons. Conventional air defense systems struggle to efficiently counter swarms of drones using expensive missiles. High-powered lasers promise cheaper, faster countermeasures by using electricity rather than single-use explosive ordinance.
Startups & Strategic Partnerships
Laser-fusion company Xcimer recently struck a deal with RTX Ventures, the investment arm of the defense contractor RTX Corp. The partnership gives Xcimer funding, while providing RTX a path to explore using its powerful laser systems for defense applications. Although Xcimer’s current laser facility—dubbed Phoenix—is far less powerful than what will eventually be needed for full-scale fusion power generation, it is sufficient to catch defense industry interest.
Pacific Fusion is another example. The company has signed a memorandum of understanding with the National Nuclear Security Administration, aiming to collaborate on high-energy-density experiments. Their new demonstration facility, located in New Mexico near major national labs, is intended to prove the ability to produce net energy. But the facility’s capabilities are also useful for national security testing and research, particularly for experiments stronger than those currently employed in weapons-related contexts.
For Pacific Fusion, involvement in defense is not a sideline—it’s woven into the core strategy. Its founding technical leadership has experience at top national labs and agencies, shaping both innovation and relationships needed to serve dual-use goals. For these companies, the stretch between climate ambition and defense contracts is relatively short.
At present, the pivot toward defense is helping fusion startups shore up resources and validate technologies under real-world constraints. But it also raises questions about how to balance transparency, public benefit, and strategic secrecy.
This isn’t just about diversifying revenue streams—it’s a reimagination of how fusion gets funded, scaled, and validated.
What this shift means is significant: fusion energy may reach testable power milestones sooner thanks to defense infrastructure, while military demand could steer what fusion systems are designed for. In other words, the divide between clean energy and national security may be narrower than imagined—and for fusion, that shift could define the path ahead.
