Fusion Startups Xcimer and Pacific Fusion Strike New Deals With RTX and the NNSA

Two fusion power startups have struck new defense-sector partnerships within two and a half weeks of each other, a sign that the industry’s original customer, the national security establishment, is becoming a more central part of how these companies plan to survive long enough to reach the electrical grid.

On September 10, 2026, laser-fusion company Xcimer Energy announced that RTX Ventures, the venture capital arm of the defense contractor RTX (renamed from Raytheon Technologies in 2023), had made a minority investment in the company and signed a teaming agreement to explore adapting Xcimer’s laser technology for military use. Two and a half weeks earlier, on August 25, the National Nuclear Security Administration (NNSA) signed a memorandum of understanding with a separate company, Pacific Fusion, as that startup broke ground on a $1 billion research campus in Albuquerque, New Mexico.

Neither deal commits either startup to abandoning its original goal of putting fusion power on the grid. But both agreements formalize a return to the industry’s roots in Cold War weapons physics, at a moment when the venture capital that typically bankrolls climate-tech startups like these has cooled, according to TechCrunch, which first reported the pattern.

Xcimer: one laser, two customers

Denver-based Xcimer operates what it says is the largest privately owned laser system in the world, a prototype called Phoenix. The company’s approach compresses fuel targets with laser pulses until the atoms inside fuse. On June 10, 2026, the Department of Energy formally approved Xcimer’s preconceptual design and technology roadmap milestone for Athena, its proposed commercial power plant architecture, under the department’s Milestone-Based Fusion Development Program, according to Xcimer’s own announcement. Athena is designed around a krypton fluoride excimer laser, a liquid-wall chamber lined with a molten salt curtain, and continuous operation at repetition rates up to once per second.

“The question facing laser fusion is no longer whether the physics works. The question is how fast we can industrialize it,” Xcimer CEO and Chief Science Officer Conner Galloway said in that announcement.

Under the new RTX agreement, RTX Ventures’ investment will help fund development of what the companies call Xcimer’s “multi-kilojoule-class pulsed-laser technologies,” while a separate teaming agreement lets RTX explore packaging that same laser technology into its own defense systems, according to the companies’ joint announcement. “Our excimer-based laser technology offers the performance, speed and inherent scalability needed at a fraction of the cost and complexity of today’s systems,” Galloway said of the deal. RTX Chief Technology Officer Juan de Bedout said the pairing “lines up perfectly with our expertise in areas like advanced sensing, command and control and air defense.”

The military’s interest traces to a cost problem that has grown more visible as drone warfare has spread: intercepting a cheap, disposable drone with an expensive guided missile. A Patriot interceptor typically costs several million dollars; the drones it is sometimes used against can cost a few hundred. TechCrunch’s report highlighted one incident, also previously covered by Fox News, in which a U.S. ally used a roughly $3 million Patriot missile to shoot down a $200 consumer drone. Laser weapons promise to invert that math: instead of firing one expensive, single-use missile per shot, they draw electricity from a generator or a ship’s own reactor or engine, letting a defender fire repeatedly at a fraction of the cost per engagement. Xcimer still expects its fusion technology to begin delivering electricity to the grid by the mid-2030s; the RTX partnership does not change that timeline, but it gives the company a second paying customer while it gets there.

Pacific Fusion and the NNSA: stockpile science, not a power plant

Pacific Fusion’s arrangement runs through a different part of the government. On August 25, NNSA Administrator Brandon Williams and Pacific Fusion co-founder and Chief Technical Officer Keith LeChien signed a memorandum of understanding establishing a framework to collaborate on “high yield fusion, high-energy-density science, pulsed-power technologies, advanced materials, modeling and simulation, and other areas of shared national interest,” according to the Department of Energy’s own announcement. The MOU is a framework agreement; it does not by itself commit either side to funding, and any specific projects would require separate agreements.

The signing coincided with Pacific Fusion breaking ground on its Research and Manufacturing Campus in Albuquerque, according to World Nuclear News. The site sits not far from Sandia and Los Alamos National Laboratories, where LeChien previously worked, per TechCrunch. The centerpiece of the roughly $1 billion campus is the company’s “Demonstration System,” designed to produce fusion output bursts exceeding 100 megajoules and reach net facility gain, generating more energy than the facility itself consumes, by 2030. Pacific Fusion says it will be the only high-yield fusion facility under construction in the United States.

“It turns out that the facility that we’re building also has utility in this world-leading defense application,” LeChien told TechCrunch. Co-founder and Chief Operating Officer Carrie von Muench said defense applications were “always on our mind” for the company, not an afterthought bolted on later. NNSA Administrator Williams said “public-private partnerships are essential to unleashing American innovation” in the global fusion race, per the department’s announcement.

High-yield fusion facilities like Pacific Fusion’s matter to the NNSA because they can recreate some of the extreme, high-energy-density conditions nuclear weapons scientists once studied through live underground testing, which the United States has not conducted since a 1992 moratorium. Lawrence Livermore National Laboratory has run laser fusion experiments in service of that stockpile-stewardship mission for decades, most recently through its National Ignition Facility, which in December 2022 became the first laser fusion experiment to produce more energy from its fusion reaction than the laser energy delivered to the target. Pacific Fusion’s agreement with the NNSA extends a version of that model to a high-yield facility that a private company, not the government, will build and own.

A second funding stream, not an abandoned one

Fusion has captured an outsized share of climate-tech venture funding in recent years, but the physics remains capital-intensive, and broader climate-tech investment has stalled. Defense dollars offer these companies a second funding stream that does not require changing the underlying science, only the customer. Both Xcimer and Pacific Fusion frame the defense work as additive to, not a replacement for, their grid-power ambitions. But two separate agreements landing within two and a half weeks of each other suggest that fusion’s oldest backer, the national security establishment that helped create the field during the Cold War, is once again becoming central to how the industry pays its bills.