Fusion Startups Renew Ties With Defense Sector Amid Funding Shifts

Fusion power startups are accelerating a strategic pivot toward defense applications, driven by tightening venture capital funding in the climate technology sector and a rising military demand for directed-energy weapons, according to reporting from TechCrunch. While commercial fusion firms maintain their primary long-term goal of putting electrons on the electrical grid, several early-stage companies are actively securing defense-related partnerships, investments, and government agreements to sustain their capital-intensive research.

The modern intersection of nuclear fusion and national security builds on decades-old foundations established during the Cold War, when physicists originally explored constructive applications for thermonuclear bomb physics. That defense connection never fully disappeared, evidenced by the 2022 fusion power experiment at the National Ignition Facility, a federal site supporting national security applications for over 25 years. However, the current acceleration is heavily influenced by financial pressures. Venture capital funding for climate tech has stalled, prompting expensive fusion enterprises to seek alternative capital sources from the defense industry.

Defense Applications and Directed-Energy Weapons

The renewed military interest stems largely from how unmanned aerial systems and consumer drones have reshaped modern warfare. Traditional air defense systems were built to intercept larger, human-piloted aircraft, creating severe cost mismatches on the battlefield. For instance, roughly a decade ago, a United States ally utilized a $3 million Patriot missile to shoot down a $200 consumer drone.

Laser weapons offer a potential solution by altering that economic equation. Unlike traditional missiles that rely on a single, expensive, one-use unit per engagement, laser systems fire rapidly and at a much lower cost per shot using electricity drawn from shipboard reactors, generators, or engines. Because laser-based fusion startups are already developing high-powered laser architectures to initiate fusion reactions, defense contractors view them as ideal partners for advancing directed-energy weapon capabilities.

Xcimer and Pacific Fusion Secure Defense Partnerships

Denver-based startup Xcimer announced a partnership and investment from RTX Ventures, the venture capital arm of aerospace and defense conglomerate RTX, which includes Raytheon. Under the agreement, Xcimer obtains financial backing while RTX explores potential defense applications for Xcimer’s high-power laser systems. Xcimer currently operates what it describes as the largest privately owned laser system in the world, named Phoenix, which runs at an order of magnitude lower power than what a full-scale commercial power plant will require but remains powerful enough to draw defense sector attention.

Similarly, Pacific Fusion signed a memorandum of understanding with the National Nuclear Security Administration (NNSA) to collaborate on high-energy-density fusion experiments. The company recently broke ground on a demonstration facility in New Mexico situated near Sandia National Laboratories and Los Alamos National Laboratories. While the facility’s main objective is proving that its design can generate more energy than it consumes, the resulting fusion reactions will also far exceed the power levels currently used by the government for nuclear weapons experiments.

It turns out that the facility that we’re building also has utility in this world-leading defense application.

Keith LeChein, Co-founder and Chief Technical Officer at Pacific Fusion (via TechCrunch)

Pacific Fusion co-founder and chief operating officer Carrie von Muench noted that defense applications were always a consideration for the team. Chief technical officer Keith LeChein previously held roles at Sandia National Laboratories, Lawrence Livermore National Laboratory, and the National Nuclear Security Administration, anchoring the startup’s deep ties to the U.S. national security laboratory complex.