NASA plans 2028 Mars mission using nuclear fission propulsion

NASA is planning the Space Reactor-1 Freedom (SR-1 Freedom) mission, a technology demonstrator scheduled for launch in late 2028. The approximately 12,000-kilogram spacecraft aims to become the first interplanetary vessel to utilize a nuclear fission reactor for propulsion beyond Earth orbit.

Targeting a December 2028 launch window, the mission is expected to reach the vicinity of Mars in 2029. Rather than landing on the planet, the spacecraft will perform a flyby and deploy the SkyFall payload, which consists of three helicopters inspired by the Ingenuity design. These helicopters are intended to survey the Martian environment, monitor weather, and use ground-penetrating radar to search for subsurface ice.

The reactor uses high-assay low-enriched uranium fuel and a closed Brayton cycle power-conversion system to produce 20 kilowatts of electricity. The integrated system is designed to generate up to 48 kilowatts of electrical power to support Hall-effect thrusters. This mission seeks to establish flight heritage for nuclear hardware and demonstrate how nuclear-generated electricity can sustain deep-space propulsion where solar energy is less effective.