Antares Wins U.S. Air Force Space Nuclear Energy Technology Contract

Antares recently announced that it has received the “Strategic Breakthrough Award” from the Office of the Assistant Secretary of the Air Force for Space Acquisition and Integration to advance space nuclear energy technology development. The company said this is currently the largest contract awarded by the U.S. War Department in the field of space nuclear energy.

Antares CEO and co-founder Jordan·Bramble said that space applications have been a core focus since the company's founding, and that cooperation with the Space Force has turned related concepts into formal space missions. He said nuclear fission technology is expected to provide space missions with strategic capabilities that are currently difficult to achieve.

Under the project arrangement, Antares will carry out a ground nuclear power demonstration of the R1-S reactor and advance the integration of the reactor with the spacecraft so as to obtain flight certification before launch. The company also plans to use the power-generating Mark-1 reactor to power an integrated space-ground project operating in orbit, with related tests planned for 2027.

Antares stated that space nuclear energy technology can break through the limitations of spacecraft propulsion and energy supply, enabling spacecraft to have more flexible maneuverability and supporting missions with higher power demands, including stronger computing loads, directed energy systems, and future electromagnetic warfare-related applications.

On June 4, 2026, the Antares Mark-0 microreactor achieved initial criticality at Idaho National Laboratory, with the project authorized by the U.S. Department of Energy. Antares said the company thus became the first private company to achieve criticality of an advanced reactor under the U.S. Department of Energy's reactor pilot program. Its Mark-1 reactor is planned to operate for more than 6 months in 2027 and be integrated with a nitrogen closed Brayton cycle power conversion system.

This contract supports the goals set out in Executive Order No. 14369, “Ensuring American Space Superiority,” as well as the U.S. national space nuclear energy initiative established by NSTM-3. The initiative proposes launching a nuclear reactor in space as early as 2028 and deploying a nuclear reactor on the lunar surface in 2030.

Founded in 2023, Antares is a nuclear fission energy company mainly developing compact microreactors for defense and space applications, providing power to areas that traditional energy sources are difficult to cover. The company said it has currently obtained more than $600 million in financing and plans to begin generating power using advanced reactors in 2027, with the first products expected to be deployed to U.S. military facilities in 2028. Antares has operating facilities in Torrance, California; Idaho Falls, Idaho; and Aiken, South Carolina.