Antares Prime: 145,000 sq-ft vertically integrated R&D + manufacturing facility opened February 2025 in Torrance, California. Houses component manufacturing, EDU (Electrically Heated Demonstration Unit) testing, and ultimately R1 reactor assembly. Vertical integration is core to the Antares "build nuclear hardware quickly and iteratively" thesis — modeled on aerospace iterative product development.
**Announced April 22, 2026 (5 days ago)** — Antares selected by the Department of the Air Force in conjunction with the Defense Innovation Unit (DIU) for proposed deployment of a prototype R1 microreactor at Joint Base San Antonio under the Advanced Nuclear Power for Installations (ANPI) initiative. Site selected for utility infrastructure, land availability, and critical mission requirements. Antares anticipates siting, licensing, constructing, operating, and decommissioning the R1. Target deployment: 2028 or earlier. (Companion ANPI selections also went to Radiant and Westinghouse for other Air Force bases.)
First Antares reactor build under the DOE Reactor Pilot Program. Targeting criticality before July 4, 2026. Validates control systems, neutronics models, testing facility, and fuel ahead of the Mark-1 prototype. Major regulatory de-risking milestones: Preliminary Documented Safety Analysis (PDSA) approved January 2026 → Documented Safety Analysis (DSA) approved April 2026 under DOE-STD-1271 → DOE Readiness Review now underway. Built at INL existing test facility; same facility will host Mark-1 in 2027.
Summer 2025 — Antares conducted an electrically-heated demonstration of its reactor in partnership with NASA at Marshall Space Flight Center. Validated thermal management, power conversion, and component performance without nuclear fuel. Anchors the Antares space-applications commercial thesis.
Antares's first-of-a-kind electricity-producing reactor. Will use same INL test facility and fuel batch as Mark-0. Full Brayton cycle power generation. Validates the commercial production design ahead of 2028 production deployments for defense + space customers.
Antares's flagship reactor — 100 kW to 1 MWe output. Sodium heat pipe-cooled (passive, redundant heat transfer with no pumps). TRISO particle fuel in prismatic graphite core. Graphite + boron carbide control drums with independent actuator motors — design heritage from historical space reactors. Simple recuperated nitrogen closed Brayton cycle for power conversion at <300 psi (vs ~2,200 psi for water-cooled designs — major mechanical simplification). KEY DESIGN PHILOSOPHY: "modular, transportable, design for strategic energy applications on Earth and in space." Years of operation between refuelings; no commercial grid dependency; no specialized on-site infrastructure. Smallest power output in the dataset (30x smaller than Aalo-1, 10x smaller than Radiant Kaleidos).
Foundational seed round October 2023 — first reported funding round for Antares Industries. Established the company's core engineering team and Torrance California operations.
Three Small Business Innovation Research awards from US Air Force, totaling $3.75M. Same month received DOE GAIN voucher for Oak Ridge collaboration. Established Antares's defense customer pipeline that ultimately led to ANPI selection.
Antares filed for $79.5M exempt offering October 2025 (per Tracxn) suggesting a Series A or growth equity round between Seed and Series B. Specific terms not publicly detailed at time of writing.
Two contracts with Idaho National Laboratory (operated by Battelle Energy Alliance) totaling approximately $40M to support next phases of R1 microreactor development including build and demonstration in an existing INL facility.
Series B closed December 2, 2025. Led by Shine Capital. $71M new equity capital + $25M debt for equipment, factory build-out, and uranium procurement. Shine Capital General Partner Alex Hartz: "No nuclear startup has turned on a fission reactor this century. Antares is poised to achieve this milestone in 2026." Brings cumulative funding to $140M+. Funds Mark-0 demonstration, Mark-1 electricity-producing prototype (2027), and 2028 production deployments.