Antares raises $470 million to deploy nuclear microreactors to military bases
Antares raised $470 million in Series C funding on July 27, 2026, to deploy factory-built nuclear microreactors to US military bases starting in 2028.
Photo by Wolfgang Weiser on Pexels
Antares, a nuclear fission energy company based in Torrance, California, raised $470 million in Series C funding announced July 27, 2026, to move its factory-built microreactors from a demonstrated design to fielded power systems for defense and space customers. The round was co-led by Paradigm and Caffeinated Capital, with participation from Point72 Ventures, Shine Capital and Industrious Ventures, according to the company.
The Series C financing comprises $370 million in equity and $100 million in debt, bringing Antares’ total funding to more than $604 million since its founding in 2023, including a $96 million Series B round in December 2025. The company plans initial deployments to US military installations beginning in 2028.
What the nuclear microreactor funding will pay for
The capital follows Antares achieving initial criticality of its Mark-0 microreactor on June 4, 2026, at Idaho National Laboratory under a US Department of Energy Reactor Pilot Program authorization, in partnership with the DOE, the lab and BWX Technologies. The company says this was the first privately developed non-light-water reactor to reach criticality in the United States in more than four decades, using a full-scale core running on TRISO fuel.
| Milestone | Date | Detail |
|---|---|---|
| Series B financing | December 2025 | $96 million raised |
| Mark-0 reactor criticality | June 4, 2026 | First private non-light-water reactor criticality in the US in 40+ years, Idaho National Laboratory |
| Series C financing | July 27, 2026 | $470 million raised ($370M equity, $100M debt); total funding over $604 million |
| Mark-1 electricity-producing reactor | Targeted 2027 | Company’s stated goal |
| Initial military deployments | Targeted 2028 | Includes US Air Force under the Advanced Nuclear Power for Installations initiative |
Antares’ microreactors target an output range of 100 kilowatts to 1 megawatt and are designed to run without refueling for more than six years. The company said it is building toward Executive Order 14299, which directs the Department of War to operate a reactor at a domestic military installation by September 30, 2028, and cited the U.S. Air Force under the Advanced Nuclear Power for Installations initiative as a customer.
“Instead of relying on hype, Antares stands apart in the advanced nuclear space by delivering concrete results, such as winning the race to criticality and securing major customers like the U.S. Air Force,” said Varun Gupta, partner at Caffeinated Capital. Jordan Bramble, Antares’ chief executive and co-founder, said the company has “shifted to the race to commercialization” after reaching criticality in June.
Antares’ approach fits a broader push toward compact, factory-built reactors. Small modular reactors, which include microreactors like Antares’, are being developed with capacity under 300 megawatts and, unlike Antares’ current demonstration, no SMR was yet operating commercially anywhere as of mid-2026, according to prior Winss Solutions reporting on the technology.
About Antares
Antares was founded in 2023 and develops compact nuclear microreactors for defense and space applications. The company operates facilities in Torrance, California; Idaho Falls, Idaho; and Aiken, South Carolina. It achieved initial criticality of its Mark-0 microreactor in 2026 under the DOE Reactor Pilot Program and has stated plans to produce electricity from an advanced reactor in 2027, ahead of initial deployments to US military installations beginning in 2028. The July 2026 Series C round, which follows a $96 million Series B in December 2025, is intended to fund that transition from demonstration to fielded reactors.
Sources: Business Wire (Antares); TechCrunch
Featured image: photo by Wolfgang Weiser on Pexels (free Pexels license).
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I specialize in sustainability education, curriculum co-creation, and early-stage project strategy. At WINSS, I craft articles on sustainability, transformative AI, and related topics. When I’m not writing, you’ll find me chasing the perfect sushi roll, exploring cities around the globe, or unwinding with my dog Puffy — the world’s most loyal sidekick.
