US-based Antares has cleared a key regulatory hurdle for its first power-generating nuclear microreactor. The US Department of Energy (DOE) has approved the Nuclear Safety Design Agreement for the company’s Mark-1 system.

The decision opens the door for construction and testing at Idaho National Laboratory. It also sets the formal safety standards and technical baseline that will govern the plant until it goes live.

The green light comes as the Pentagon accelerates efforts to field reliable, portable nuclear power on Earth and in orbit. In September 2026, the US Space Force granted Antares a $161 million Strategic Breakthrough award to build space-qualified reactors. 

Military planners want persistent electricity for satellites to support high-demand computing and directed-energy equipment in contested orbital zones.

Mark-1 serves as the crucial ground-based bridge toward those ambitions. Antares plans to run the reactor at full electrical power for six months during a major testing campaign in 2027. Unlike pure experimental rigs, Mark-1 is designed as a commercially representative plant.

The reactor will produce electricity by feeding heat into a specialized nitrogen closed Brayton cycle system. Operating data gathered throughout the test run will directly inform Antares’ first military deliveries. Under the US Army’s Janus program, the company plans to install the first of several operational microreactors at Fort Bragg, North Carolina, starting in 2028.

“Mark-1 isn’t a scaled-down, stand-in test rig,” said Jordan Bramble, chief executive and co-founder of Antares.

Source link