Torrance, Calif.-based Antares Nuclear was awarded $161 million by the U.S. Air Force last week to advance its nuclear reactor technology for space applications.
The Air Force award to Antares represents the largest Department of Defense contract for space nuclear power so far, according to the company’s Sept. 11 press release.
Under the program, the company will have to conduct a nuclear ground demonstration of its named R1-S reactor technology, and coordinate with a spacecraft for “flight certification forward of launch,” Antares said. The company also said it will need to “power an operational ground-to-space asset with Mark-1, its electricity-producing reactor, scheduled for testing in 2027.”
The company’s R1 commercial microreactor design features portable sodium heat pipe-cooled technology that can generate up to one-megawatt of electricity. The reactor is also fueled by tri-structural isotropic – or TRISO – fuel. The Mark-1 reactor is the technology that Antares is developing at the Department of Energy’s Idaho National Laboratory under DOE’s reactor pilot program.
This award comes as a part of the Donald Trump administration’s push for expanded use of nuclear energy. In December 2025, Trump issued the executive order Ensuring American Space Superiority that seeks to deploy a nuclear reactor on the moon by 2030 and deploy a reactor in orbit as early as 2028.