On April 14, 2026, U.S. Office of Science and Technology Policy (OSTP) issued National Science and Technology Memorandum 3 (NSTM-3), officially launching the National Initiative for American Space Nuclear Power. The memorandum establishes accelerated, near-term timelines for space nuclear deployment, aiming to place reactors in orbit as early as 2028 and on the lunar surface by 2030.
In alignment with these policy targets, NASA has detailed the pathfinder missions designed to fulfill these mandates: Space Reactor-1 (SR-1) Freedom and Lunar Reactor-1 (LR-1). NASA is serving as the prime integrator for these missions, working in close partnership with the Department of Energy (DOE) and private-sector innovators.
NASA’s SR-1 and LR-1 missions
To meet the administration’s goals, NASA is implementing an incremental development approach where early spaceflight retires nuclear flight risk and builds the domestic supply chain.
- Space Reactor-1 (SR-1) Freedom: Targeted for a December 2028 launch, SR-1 will be the first spacecraft to utilize a nuclear fission reactor for propulsion beyond Earth orbit. The mission is designed to repurpose NASA’s nearly built Power and Propulsion Element spacecraft bus. Utilizing a mature uranium fuel form and Brayton power conversion, the reactor will deliver more than 20 kilowatts of electrical power. Within 48 hours of escaping Earth’s gravity, the system will start the fission reactor and power electric thrusters. Using nuclear electric propulsion, SR-1 will navigate to Mars to deliver the “Skyfall” payload—three Ingenuity-class helicopters equipped to survey potential human landing sites and search for subsurface water.
- Lunar Reactor-1 (LR-1): Scheduled for a 2030 lunar landing, LR-1 will deliver the first fission nuclear reactor to the Moon. Acting as a follow-on to the SR-1 mission, LR-1 is a fission surface-power system designed to sustain Moon Base operations. This capability is necessary to maintain power through lunar periods of darkness and in permanently shadowed craters where solar power is entirely ineffective.
Interagency mandates and procurement strategy
The broader NSTM-3 policy mandates parallel design competitions to support these deployments. While NASA focuses on the SR-1 and LR-1 systems, the Department of War (DOW) and the DOE have distinct supporting mandates:
- DOW Targets: The DOW is tasked with deploying a mission-enabling mid-power in-space reactor by 2031. To maximize early efficiencies, the DOW will redirect its available space nuclear funding during the initiative’s first year to support NASA’s initial development programs.
- DOE Support: The DOE will assess the readiness of the U.S. nuclear industrial base to manufacture up to four space reactors within five years, with a report due in 60 days. Furthermore, the DOE is mandated to supply uranium for reactor fuel if commercial sources are unavailable or insufficient.
To govern these developments, the policy establishes a strict commercial procurement framework designed to distribute risk and incentivize rapid progress. Federal agencies are instructed to use firm fixed-price contracts, releasing funding payments only upon the successful completion of milestones. The government will heavily favour milestones that demonstrate the tangible delivery of hardware and real capabilities.