Space Reactor-1 Freedom Program

Space Reactor-1 Freedom is NASA’s nuclear-electric-propulsion development program and pathfinder mission targeting a late-2028 launch toward Mars. A fission reactor will supply heat to a closed Brayton-cycle conversion system, producing electricity for spacecraft systems and electric thrusters. NASA’s October 2026 development update identifies Idaho National Laboratory as the reactor developer and Sierra Lobo as the power-conversion-system provider. The reactor is to remain inactive until the spacecraft leaves Earth orbit. The planned mission will carry SkyFall, a payload of three helicopters evolved from Ingenuity, and demonstrate capabilities intended to inform later lunar surface power. Launch, reactor operation beyond Earth orbit and SkyFall delivery remain planned outcomes.