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Antares wins $161 million Space Force award for nuclear reactor demonstration. September 11, 2026 Rendering of a nuclear-powered spacecraft in Earth orbit Antares has been selected for a $161 million Strategic Breakthrough award to demonstrate nuclear power technology for space, giving the nuclear energy company a path to test its R1-S reactor on the ground and integrate the system with a spacecraft ahead of flight certification and launch. The award was made through the Office of the Assistant Secretary of the Air Force for Space Acquisition and Integration and represents the largest Department of War award for space nuclear power to date, according to Antares. Under the program, Antares will conduct a nuclear ground demonstration of its R1-S system before integrating the reactor with a spacecraft for flight certification. The work moves the company's compact fission technology toward an operational space mission rather than limiting development to reactor testing. Antares will also use Mark-1, its electricity-producing reactor, to power an operational ground-to-space asset. Testing of Mark-1 is scheduled for 2027, creating another step in validating how the company's reactor and power-conversion technologies perform as an integrated energy system. "This partnership with the Space Force turns that long-held vision into a codified space mission," CEO and co-founder Jordan Bramble said. "Fission will unlock strategic capabilities that are impossible today." The program addresses one of the central infrastructure constraints for more power-intensive spacecraft: generating reliable electricity while maintaining sufficient propulsion capacity for maneuvering. Nuclear fission could provide continuous power for systems with heavier computing requirements and other high-demand payloads without depending on conventional spacecraft power architectures alone. Antares is targeting applications including advanced computing, directed-energy systems and electromagnetic warfare. The company also sees nuclear power as a way to reduce propulsion-related operational constraints, potentially allowing spacecraft to conduct more dynamic maneuvers while maintaining power for onboard systems. The award builds on a reactor milestone Antares reached earlier this year. On June 4, 2026, its Mark-0 microreactor achieved initial criticality at Idaho National Laboratory under Department of Energy authorization. Antares said the milestone made it the first private company to bring an advanced reactor to criticality through the DOE Reactor Pilot Program. The next stage centers on producing usable electricity. Antares plans to operate its Mark-1 reactor for more than six months in 2027, integrating it with the company's nitrogen closed Brayton cycle power-conversion system. That configuration is designed to move development beyond reactor physics and demonstrate an integrated system capable of converting reactor heat into electricity. Successfully coupling the reactor with power conversion is an important operational requirement for both terrestrial and space applications. The company's development sequence moves from Mark-0 criticality to extended Mark-1 electricity production, followed by the R1-S ground demonstration and spacecraft integration required for a potential flight mission. The Strategic Breakthrough program also aligns with federal plans to accelerate deployment of nuclear power beyond Earth. Antares said the award supports goals established by Executive Order 14369, "Ensuring American Space Superiority," and the National Initiative for American Space Nuclear Power established through NSTM-3. Those policies call for nuclear reactors to be launched into space as early as 2028 and deployed on the lunar surface by 2030. Founded in 2023, Antares is developing compact nuclear microreactors for defense and space applications. The company has raised more than $600 million and expects initial production deployments at U.S. military installations beginning in 2028. Antares operates facilities in Torrance, California; Idaho Falls, Idaho; and Aiken, South Carolina. The $161 million award adds a dedicated space mission to a development program that is now moving from reactor criticality toward electricity generation, spacecraft integration and eventual deployment.

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Antares selected for $161M Strategic Breakthrough award to demonstrate space reactor. Published at September 11th 2026, 10:28 AM EDT via Business Wire i This article is third-party content and does not represent the views of this site. We make no guarantees regarding its accuracy or completeness. Effort will carry a nuclear-powered spacecraft toward flight qualification Nuclear Energy Antares today announced it has been selected by the Office of the Assistant Secretary of the Air Force for Space Acquisition and Integration for a Strategic Breakthrough award to advance nuclear power for space. It marks the largest current Department of War award in space nuclear power. Rendering of a nuclear-powered spacecraft in Earth orbit "Space has been core to the Antares thesis since the company was founded," said Jordan Bramble, CEO and co-founder of Antares. "This partnership with the Space Force turns that long-held vision into a codified space mission. Fission will unlock strategic capabilities that are impossible today." Through this program, Antares will perform a nuclear ground demonstration of the R1-S and integrate with a spacecraft for flight certification forward of launch. The company will also power an operational ground-to-space asset with Mark-1, its electricity-producing reactor, scheduled for testing in 2027. Space nuclear has been core to Antares from day one. It removes propulsion constraints for the Space Force, allowing spacecraft to maneuver without regret and carry out dynamic operations that were once impossible. Most importantly, it brings high, always-on power to support heavier compute loads, directed energy systems, and the future of electromagnetic warfare. On June 4, 2026, Antares' Mark-0 microreactor achieved initial criticality at Idaho National Laboratory under Department of Energy authorization, making Antares the first private company to bring an advanced reactor to criticality under the DOE Reactor Pilot Program. The company's Mark-1 reactor is scheduled to operate for more than six months in 2027, integrated with its nitrogen closed Brayton cycle power conversion system. The award supports goals set in Executive Order 14369, "Ensuring American Space Superiority," and the National Initiative for American Space Nuclear Power established by NSTM-3, which direct the launch of nuclear reactors in space as early as 2028 and on the lunar surface by 2030. About Antares Antares is a nuclear fission energy company developing compact microreactors for defense and space applications, delivering safe, reliable power where traditional energy sources cannot. Founded in 2023 and backed by over $600 million in funding, Antares achieved initial criticality of its Mark-0 microreactor in 2026 under the DOE Reactor Pilot Program, and is on track to produce electricity from an advanced reactor in 2027, with initial production deployments to U.S. military installations beginning in 2028. Antares operates facilities in Torrance, California; Idaho Falls, Idaho; and Aiken, South Carolina. Contacts. Report this content If you believe this article contains misleading, harmful, or spam content, please let us know.