NASA advances Space Reactor-1 Freedom nuclear power module

NASA is progressing with the Space Reactor-1 (SR-1) Freedom mission, which aims to be the first spacecraft to utilize nuclear fission power beyond Earth’s orbit. Scheduled for a late-2028 launch, the mission will travel to Mars to deliver the ‘SkyFall’ scientific payload.

To accelerate development, NASA is reusing hardware originally intended for the lunar Gateway station. The mission’s core component, the nuclear power module, will be located at the end of a long boom. Idaho National Laboratory is currently constructing the reactor, which will use high-assay low-enriched uranium dioxide fuel protected by boron carbide. For safety, the reactor will remain idle until the spacecraft has exited Earth orbit.

Sierra Lobo has been selected to provide the closed Brayton-cycle energy conversion system. This system will convert thermal energy from the fission reactor into more than 20 kilowatts of electricity by expanding gas through a turbine and generator. This power output is expected to be sufficient to support the system for an entire year.