Kilowatt-Class Fission Power Systems for Science and Human Precursor Missions

Abstract Nuclear power provides an enabling capability for NASA missions that might otherwise be constrained by power availability, mission duration, or operational robustness. NASA and the Department of Energy (DOE) are developing fission power technology to serve a wide range of future space uses. Advantages include lower mass, longer life, and greater mission flexibility than competing power system options. Kilowatt-class fission systems, designated “Kilopower,” were conceived to address the need for systems to fill the gap above the current 100-W-class radioisotope power systems being developed for science missions and below the typical 100-kWe-class reactor power systems being developed for human exploration missions. This paper reviews the current fission technology project and examines some Kilopower concepts that could be used to support future science missions or human precursors. Fission Technology Development NASA and the Department of Energy (DOE) are collaborating on fission power technology development to enable future space power systems for science and exploration. Project participants include the NASA Glenn Research Center, NASA Marshall Space Flight Center, Jet Propulsion Laboratory (JPL), and DOE National Laboratories at Idaho, Los Alamos, Oak Ridge, and Sandia. The present work effort resides under the Space Technology Mission Directorate (STMD), Game Changing Development Program as the Nuclear Systems Project. The team has been in place since the end of the Prometheus Program performing analysis and hardware testing to establish technology readiness. The Nuclear Systems Project has been addressing the typical fission power design regime aimed at larger fission power systems (FPSs) for human exploration missions in the 10 to 100 kWe range with extensibility into the megawatt class. The current focus is a nonnuclear Technology Demonstration Unit (TDU) that will be tested in thermal vacuum to demonstrate integrated system performance (Refs. 1 and 2). The TDU test assembly, which includes a NaK-cooled reactor simulator and one 12-kWe Stirling convertor, serves as an important hardware foundation for large-scale FPSs to verify technology readiness and support mission application studies. The TDU test configuration is based predominantly on a lunar or Mars surface power system (Refs. 3 and 4). Fission surface power (FSP) systems for the Moon and Mars could produce between 10 and 100 kWe. Emphasis is on low risk, operational robustness, and affordability. The reactor design leverages terrestrial technology with fast-spectrum UO