The author’s of this white paper make a compelling argument for switching the development of space nuclear power reactor’s fuel source from Highly Enriched Uranium (HEU) to Low Enriched Uranium (LEU). The basis of their argument is political and economic. Due to proliferation concerns, an HEU based space reactor may be hard to literally get off the ground. Unfortunately, the devils of human nature are once again preventing progress. An HEU space reactor system would be the logical choice due to the smaller mass requirements.