Antares Selected for $161M Strategic Breakthrough Award to Demonstrate Space Reactor

Effort will carry a nuclear-powered spacecraft toward flight qualification

TORRANCE, Calif.--(BUSINESS WIRE)--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.

“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.