NASA Office of Inspector General
Every spacecraft that ventures beyond the reach of useful sunlight - to the outer planets, the permanently shadowed lunar poles, the dusty surface of Mars - runs on the same scarce substance: plutonium-238, a fuel no longer made anywhere on Earth except by a fragile government production chain. In March 2023 NASA’s Office of Inspector General published the definitive public examination of that chain: IG-23-010, NASA’s Management of Its Radioisotope Power Systems Program, reproduced here in full facsimile.The fifty-two-page audit is the best single document on a capability the public rarely sees. It explains the physics and the supply chain: why Pu-238’s half-life and heat output make it irreplaceable for deep-space power, how the United States let production lapse after the Cold War, and how the NASA-funded, Department of Energy-operated restart at Oak Ridge and Los Alamos has crawled toward its production targets. It assesses the interagency structure in which NASA pays and DOE produces - an arrangement the OIG finds opaque in cost and accountability - and weighs projected fuel supply against the mission queue: Mars rovers, Dragonfly’s Titan rotorcraft, and the lunar night-survival systems of Artemis-era ambitions. The recommendations address cost transparency, demand forecasting, and the technology bets (next-generation RTGs, dynamic converters) that could stretch each precious kilogram.As lunar fission systems and nuclear propulsion climb the policy agenda, this report is the indispensable baseline: the audited state of America’s existing space-nuclear enterprise, against which every new ambition should be measured.The official source document is reproduced in full facsimile, with separate editorial apparatus of the public document, produced under 17 U.S.C. §105. For planetary scientists, space-nuclear advocates, interagency-governance scholars, and mission planners whose dreams run on isotopes, IG-23-010 is the document that explains the constraint.The report has only grown more relevant as space-nuclear ambitions accelerate: fission surface power directives, nuclear thermal propulsion programs, and commercial radioisotope ventures all presume an isotope and expertise base whose actual fragility this audit documented. Its account of the NASA-DOE interface -- two agencies, one mission, perpetually negotiated accountability -- is the indispensable background to every announcement promising reactors on the Moon by decade’s end, and its supply-versus-demand tables remain the public baseline against which new mission commitments should be checked. Policy momentum is cheap; plutonium is not, and this is the document that explains the difference.About this series: Nimble Ultra’s American Spacepower Documents collection puts the primary sources of the space age’s second great competition into durable, uniform print -- doctrine, strategy, intelligence, oversight, and exploration architecture, each volume an exact and complete facsimile of the official public release, with full bibliographic identification for citation. Government URLs break, documents are revised without notice, and libraries deserve stable copies; these editions fix the record as issued. Collect the doctrine shelf alongside the analytical flagship of the series, the RKHS-extended edition of Space Force Vector 2025.This 62-page Nimble Ultra paperback identifies NASA Office of Inspector General as the originating body and preserves NASA’s Management of Its Radioisotope Power Systems Program (IG-23-010) as a durable print reference. The edition is intended for policy research, technical study, teaching, professional consultation, and library collections.
