NASA has reported progress on the nuclear power module for Space Reactor-1 (SR-1) Freedom, the spacecraft planned to demonstrate fission power beyond Earth orbit on a mission to Mars. In an article published October 20, 2026, the agency said it and its partners had mutually agreed to contract actions aimed at reducing technical risk and maintaining momentum toward a launch planned for late 2028.

Sierra Lobo Inc. will provide the module's closed Brayton cycle power conversion system, which turns heat from the fission reactor into electricity for the spacecraft's nuclear electric propulsion demonstration. The work falls under a contract awarded in 2024 supporting spaceflight hardware work at NASA's Glenn Research Center in Cleveland. The reactor itself is being designed and developed by the Department of Energy's Idaho National Laboratory.

NASA said the reactor portion will remain inactive until the spacecraft leaves Earth orbit, and that interagency safety reviews and oversight by a NASA chief safety officer are part of development. SR-1 Freedom is to deliver the SkyFall science mission, three Mars helicopters evolved from the Ingenuity design. NASA said the technology could also support its Moon Base through dark periods and where solar power alone is insufficient.