1. “Uranium Enrichment,” U.S. Nuclear Regulatory Commission; https://www.nrc.gov/materials/fuel-cycle-fac/ur-enrichment.html (current as of Dec. 9, 2019).
2. M. A. GIBSON et al. “NASA’s Kilopower Reactor Development and the Path to Higher Power Missions” (2017); https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20170002010.pdf (current as of Aug. 7, 2020).
3. A feasibility study on low-enriched uranium fuel for nuclear thermal rockets – I: Reactivity potential
4. L. MASON and M. RUCKER, “Common Power and Energy Storage Solutions to Support Lunar and Mars Surface Exploration Missions,” NASA; https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20190032521.pdf (current as of Aug. 7, 2020).
5. A. J. KUPERMAN, “Avoiding Highly Enriched Uranium for Space Power,” Proc. Nuclear and Emerging Technologies for Space (NETS 2018), Las Vegas, Nevada, February 26–March 1, 2018, American Nuclear Society (2018). B. FOSTER, Written Testimony for Members’ Day Hearing: House Committee on Science, Space, and Technology, May 17, 2019.