NASA names Sierra Lobo for nuclear Mars spacecraft power conversion

(SpaceEnergy) NASA has identified Sierra Lobo as the supplier of a closed Brayton cycle power conversion system for its SR-1 Freedom nuclear-electric spacecraft, following newly disclosed contract actions.

NASA said on 20 October that it and its partners had agreed contractual measures intended to accelerate development of the spacecraft's nuclear power module and reduce technical risk ahead of a planned late-2028 launch.

Sierra Lobo will provide the system that converts heat generated by a nuclear fission reactor into electricity for spacecraft systems and electric propulsion.

The work will proceed under NASA's Space Flight Systems Development and Operations Contract III, awarded in 2024, supporting hardware development, testing and operations at Glenn Research Center in Cleveland, Ohio.

The power conversion system will be integrated with a reactor being designed and developed by the US Department of Energy's Idaho National Laboratory.

NASA's published mission specifications identify a 20kW electrical closed Brayton cycle system using high-assay low-enriched uranium fuel.

The agency said the reactor would remain inactive until the spacecraft had departed Earth orbit. Nuclear safety reviews, regulatory compliance and engineering oversight form part of the development programme.

SR-1 Freedom is intended to demonstrate nuclear electric propulsion beyond Earth orbit while delivering the SkyFall mission, comprising three Mars helicopters derived from the Ingenuity design.

NASA expects the technology to support future lunar surface reactors and deep-space propulsion systems.

The qualifying development is the newly disclosed allocation of power conversion responsibilities and associated contractual arrangements, not the previously announced spacecraft mission or the NASA–DOE cooperation agreement.

NASA did not disclose the value or execution dates of the individual contract actions.