Series B Funding Will Accelerate Nuclear Microreactor Development
Antares Working with NASA, Department of War
Advanced nuclear energy startup Antares has closed a $96 million Series B funding round. The round was led by Shine Capital, with participation from Alt Capital, Caffeinated, FiftyThree Stations, Industrious, and other investors. The round consists of $71M in new equity capital and $25M in debt for equipment, factory build-out, and uranium procurement.
“We’ve raised the capital we need to mobilize to provide resilient energy for our partners at the Department of War (DoW) and NASA.”
Jordan Bramble, Antares
Antares CEO Jordan Bramble said the new capital will fuel the company’s mission to deliver safe, reliable, and scalable nuclear power solutions. “This funding marks a major milestone for Antares,” Bramble said. “We’re months away from our first reactor demonstration, which will validate our control systems and neutronics models, develop our testing facility, and fabricate our fuel ahead of our upcoming full scale electricity producing prototype in 2027,” Bramble said. “We’ve raised the capital we need to mobilize to provide resilient energy for our partners at the Department of War (DoW) and NASA.”
Founded just over two years ago, Antares has made rapid progress in technology maturation. The company has raised over $130M in funding to date and put those resources to work building out a 145,000-square-foot facility in Torrance, California, capable of producing 10 units per year. Antares has also secured contracts with the United States Air Force, Space Force, Defense Innovation Unit (DIU), and NASA to advance its technology.
With operations in Torrance, California; Idaho Falls, Idaho; and Aiken, South Carolina, and a team of 60, Antares is working to demonstrate a low-power test reactor before July 4, 2026, and to test its first-of-a-kind electricity-producing demonstration unit in 2027. Production units will be deployed as early as 2028.
“No nuclear startup has turned on a fission reactor this century. Antares is poised to achieve this milestone in 2026, thanks to their design and licensing maturity, fuel supply chain, and swift progress in demonstrating the performance of its underlying components in partnership with Idaho National Lab and NASA,” said Alex Hartz, General Partner at Shine Capital, which led the round. “Antares’ reactor will uniquely address needs across defense, space, and critical industries while also serving as a platform for scale-up to higher power.”
Over the summer, Antares conducted an electrically-heated demonstration of its reactor in partnership with NASA at their Marshall Space Flight Center in Huntsville, Alabama. In April, Antares was selected by DIU under the Advanced Nuclear Power for Installations (ANPI) program to provide nuclear power to DoW installations. In August, the company received an allocation of High-Assay Low-Enriched Uranium (HALEU) fuel feedstock from the U.S. Department of Energy (DOE) and was selected for DOE’s new reactor pilot program, which creates a fast-track pathway for reactor demonstration and licensing.
In October, the U.S. Army announced the establishment of a program of record for advanced nuclear energy, called JANUS, targeting reactors from kilowatt class up to 20MWe. With this new funding, Antares plans to compete to provide the Pentagon with resilient energy for critical assets and infrastructure. Antares’ will also propose on NASA’s Fission Surface Power program, which aims to deliver 100 kWe of nuclear power on the lunar surface by 2030.
Brillaint work detailing the funding mechanics here. The $25M equipment debt allocation is probaly the real unlock since most reactors fail on procurement timelines not design. What gets overlooked is tht they're effectively running two parallel demonstrations (DoW instalations and NASA lunar), which is either genius risk mitigation or capital inefficent.
Great piece on Antares progres. The July 2026 timeline for a functional fission reactor is aggresive but the DoE HALEU allocation and fast-track licensing pathway really change the game here. Most interesting is how they're positioning for both defense and lunar applications simulatenously.