Antares wins $161 million Space Force contract for nuclear reactor demo
Nuclear microreactor startup Antares won a $161 million DoD award to demonstrate its R1-S reactor for spacecraft power.
what happened
Antares, a nuclear microreactor startup, said it won a $161 million Strategic Breakthrough award from the Office of the Assistant Secretary of the Air Force for Space Acquisition and Integration, which it calls the largest current DoD space nuclear award. The contract tasks Antares with a ground demonstration of its R1-S heat-pipe microreactor, integrating it with a spacecraft for flight certification, and powering an operational ground-to-space asset with its Mark-1 reactor. Antares' Mark-0 microreactor reached criticality at Idaho National Laboratory in June, and the company closed a $470 million Series C in July.
why it matters
Continuous, high-density onboard power is the constraint behind maneuverable spacecraft, directed-energy payloads and heavy onboard compute, and the Space Force is now backing a private nuclear supplier to solve it rather than developing a reactor in-house. For satellite operators and prime contractors bidding on Space Force programs, a flight-qualified in-space reactor changes what power budget they can design around; for Antares, it is a validation of its DoE-approved reactor design ahead of a stated 2028 target for launching nuclear power to orbit.
for who
Space Force contractors, satellite bus manufacturers
signal-to-noise
quick facts
- Companies
- Antares
- Category
- contract
- Impact
- major
- SNR
- 4 / 5
- Event date
- 2026-09-11
- Published
- 2026-09-11 17:27 UTC