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Radioisotope Power Systems Committee Space Studies Board Aeronautics and Space Engineering Board Division on Engineering and Physical Sciences
THE NATIONAL ACADEMIES PRESS â 500 Fifth Street, N.W. â Washington, DC 20001 NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance. This study is based on work supported by Contract NNH06CE15B between the National Academy of Sciences and the National Aeronautics and Space Administration. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the agency that provided support for the project. International Standard Book Number-13: 978-0-309-13857-4 International Standard Book Number-10: 0-309-13857-4 Copies of this report are available free of charge from: Space Studies Board National Research Council 500 Fifth Street, N.W. Washington, DC 20001 and the Aeronautics and Space Engineering Board National Research Council 500 Fifth Street, N.W. Washington, DC 20001 Additional copies of this report are available from the National Academies Press, 500 Fifth Street, N.W., Lockbox 285, Washington, DC 20055; (800) 624-6242 or (202) 334-3313 (in the Washington metropolitan area); Internet, http://www.nap.edu. Copyright 2009 by the National Academy of Sciences. All rights reserved. Printed in the United States of America
The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Ralph J. Cicerone is president of the National Academy of Sciences. The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineering programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. Charles M. Vest is president of the National Academy of Engineering. The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, upon its own initiative, to identify issues of medical care, research, and education. Dr. Harvey V. Fineberg is president of the Institute of Medicine. The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad com- munity of science and technology with the Academyâs purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the govern- ment, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Ralph J. Cicerone and Dr. Charles M. Vest are chair and vice chair, respectively, of the National Research Council. www.national-academies.org
Other Recent Reports of the Space Studies Board and the Aeronautics and Space Engineering Board A Performance Assessment of NASAâs Heliophysics Program (Space Studies Board [SSB], 2009) Assessment of Planetary Protection Requirements for Mars Sample Return Missions (SSB, 2009) Assessing the Research and Development Plan for the Next Generation Air Transportation System: Summary of a Workshop (Aeronautics and Space Engineering Board [ASEB], 2008) A Constrained Space Exploration Technology Program: A Review of NASAâs Exploration Technology Development Program (ASEB, 2008) Ensuring the Climate Record from the NPOESS and GOES-R Spacecraft: Elements of a Strategy to Recover Measurement Capabilities Lost in Program Restructuring (SSB, 2008) Final Report of the Committee for the Review of Proposals to the 2008 Engineering Research and Commercialization P Â rogram of the Ohio Third Frontier Program (ASEB, 2008) Final Report of the Committee to Review Proposals to the 2008 Ohio Research Scholars Program of the State of Ohio (ASEB, 2008) Launching Science: Science Opportunities Provided by NASAâs Constellation System (SSB with ASEB, 2008) Managing Space Radiation Risk in the New Era of Space Exploration (ASEB, 2008) NASA Aeronautics Research: An Assessment (ASEB, 2008) Opening New Frontiers in Space: Choices for the Next New Frontiers Announcement of Opportunity (SSB, 2008) Review of NASAâs Exploration Technology Development Program: An Interim Report (ASEB, 2008) Science Opportunities Enabled by NASAâs Constellation System: Interim Report (SSB with ASEB, 2008) Severe Space Weather EventsâUnderstanding Societal and Economic Impacts: A Workshop Report (SSB, 2008) Space Science and the International Traffic in Arms Regulations: Summary of a Workshop (SSB, 2008) United States Civil Space Policy: Summary of a Workshop (SSB with ASEB, 2008) Wake Turbulence: An Obstacle to Increased Air Traffic Capacity (ASEB, 2008) Assessment of the NASA Astrobiology Institute (SSB, 2007) An Astrobiology Strategy for the Exploration of Mars (SSB with the Board on Life Sciences [BLS], 2007) Building a Better NASA Workforce: Meeting the Workforce Needs for the National Vision for Space Exploration (SSB with ASEB, 2007) Decadal Science Strategy Surveys: Report of a Workshop (SSB, 2007) Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond (SSB, 2007) Exploring Organic Environments in the Solar System (SSB with the Board on Chemical Sciences and Technology, 2007) Grading NASAâs Solar System Exploration Program: A Midterm Review (SSB, 2007) The Limits of Organic Life in Planetary Systems (SSB with BLS, 2007) NASAâs Beyond Einstein Program: An Architecture for Implementation (SSB with the Board on Physics and Astronomy [BPA], 2007) Options to Ensure the Climate Record from the NPOESS and GOES-R Spacecraft: A Workshop Report (SSB, 2007) A Performance Assessment of NASAâs Astrophysics Program (SSB with BPA, 2007) Portals to the Universe: The NASA Astronomy Science Centers (SSB, 2007) The Scientific Context for Exploration of the Moon (SSB, 2007) Limited copies of SSB reports are available free of charge from Space Studies Board National Research Council The Keck Center of the National Academies 500 Fifth Street, N.W., Washington, DC 20001 (202) 334-3477/ssb@nas.edu www.nationalacademies.org/ssb/ssb.html iv
RADIOISOTOPE POWER SYSTEMS COMMITTEE WILLIAM W. HOOVER, U.S. Air Force (retired), Co-Chair RALPH L. McNUTT, JR., Johns Hopkins University, Applied Physics Laboratory, Co-Chair DOUGLAS M. ALLEN, Schafer Corporation SAMIM ANGHAIE, University of Florida, Gainesville RETA F. BEEBE, New Mexico State University WARREN W. BUCK, University of Washington, Bothell BEVERLY A. COOK, Jet Propulsion Laboratory SERGIO B. GUARRO, The Aerospace Corporation ROGER D. LAUNIUS, Smithsonian Institution FRANK B. McDONALD, University of Maryland, College Park ALAN R. NEWHOUSE, Independent Consultant, Hollywood, Maryland JOSEPH A. SHOLTIS, JR., Sholtis Engineering and Safety Consulting SPENCER R. TITLEY, University of Arizona, Tucson EMANUEL TWARD, Northrop Grumman Space Technology EARL WAHLQUIST, U.S. Department of Energy (retired) Staff ALAN C. ANGLEMAN, Study Director, Aeronautics and Space Engineering Board DWAYNE A. DAY, Program Officer, Space Studies Board CATHERINE A. GRUBER, Editor, Space Studies Board and Aeronautics and Space Engineering Board SARAH M. CAPOTE, Program Associate, Aeronautics and Space Engineering Board (through November 2008) CELESTE A. NAYLOR, Senior Program Assistant, Space Studies Board (from November 2008 through January 2009) ANDREA M. REBHOLZ, Program Associate, Aeronautics and Space Engineering Board (from February 2009)
SPACE STUDIES BOARD CHARLES F. KENNEL, Scripps Institution of Oceanography, University of California, San Diego, Chair A. THOMAS YOUNG, Lockheed Martin Corporation (retired), Vice Chair DANIEL N. BAKER, University of Colorado STEVEN J. BATTEL, Battel Engineering CHARLES L. BENNETT, Johns Hopkins University YVONNE C. BRILL, Aerospace Consultant ELIZABETH R. CANTWELL, Oak Ridge National Laboratory ANDREW B. CHRISTENSEN, Dixie State College and Aerospace Corporation ALAN DRESSLER, The Observatories of the Carnegie Institution JACK D. FELLOWS, University Corporation for Atmospheric Research FIONA A. HARRISON, California Institute of Technology JOAN JOHNSON-FREESE, Naval War College KLAUS KEIL, University of Hawaii MOLLY K. MACAULEY, Resources for the Future BERRIEN MOORE III, University of New Hampshire ROBERT T. PAPPALARDO, Jet Propulsion Laboratory JAMES PAWELCZYK, Pennsylvania State University SOROOSH SOROOSHIAN, University of California, Irvine JOAN VERNIKOS, Thirdage LLC JOSEPH F. VEVERKA, Cornell University WARREN M. WASHINGTON, National Center for Atmospheric Research CHARLES E. WOODWARD, University of Minnesota ELLEN G. ZWEIBEL, University of Wisconsin RICHARD E. ROWBERG, Interim Director (from March 2, 2009) MARCIA S. SMITH, Director (through March 1, 2009) vi
AERONAUTICS AND SPACE ENGINEERING BOARD RAYMOND S. COLLADAY, Lockheed Martin Astronautics (retired), Chair CHARLES F. BOLDEN, JR., Jack and Panther, LLC ANTHONY J. BRODERICK, Aviation Safety Consultant AMY BUHRIG, Boeing Commercial Airplanes Group PIERRE CHAO, Center for Strategic and International Studies INDERJIT CHOPRA, University of Maryland, College Park ROBERT L. CRIPPEN, Thiokol Propulsion (retired) DAVID GOLDSTON, Princeton University R. JOHN HANSMAN, Massachusetts Institute of Technology PRESTON HENNE, Gulfstream Aerospace Corporation JOHN M. KLINEBERG, Space Systems/Loral (retired) RICHARD KOHRS, Independent Consultant IVETT LEYVA, Air Force Research Laboratory, Edwards Air Force Base EDMOND SOLIDAY, United Airlines (retired) RICHARD E. ROWBERG, Interim Director (from March 2, 2009) MARCIA S. SMITH, Director (through March 1, 2009) vii
Preface Radioisotope power systems (RPSs) such as radioisotope thermoelectric generators provide electrical power for spacecraft and planetary probes that cannot rely on solar energy. To support the continued availability of the RPSs required to power NASA space missions, Congress and NASA requested that the National Research Council (NRC) undertake a study of RPS technologies and systems. The NRC formed the Radioisotope Power Systems Committee to produce this report in response to House Report 110-240 on the Commerce, Justice, Science, and Related Agencies Appropriations Bill, 2008. This report assesses the technical readiness and programmatic balance of NASAâs RPS technology portfolio in terms of its ability to support NASAâs near- and long-term mission plans. In addition, the report discusses related infrastruc- ture, the effectiveness of other federal agencies involved in relevant research and development, and strategies for reestablishing domestic production of 238Pu, which serves as the fuel for RPSs. To put the discussion of RPSs in context, the report includes some information regarding other options (i.e., solar power and space nuclear power reactors), but a detailed assessment of these alternatives is beyond the scope of the statement of task. A complete copy of the statement of task appears in Appendix A. The Radioisotope Power Systems Committee met four times between September 2008 and January 2009 at NRC facilities in Washington, D.C., and Irvine, California, and at the Jet Propulsion Laboratory in Pasadena, California. In addition, small delegations of committee members and staff visited NASAâs Glenn Research Center and the Department of Energyâs Idaho National Laboratory and Oak Ridge National Laboratory. A list of briefings received by the committee at these meetings appears in Appendix F. RPS technology has been a critical element in establishing and maintaining U.S. leadership in the exploration of the solar system. Continued attention to and investment in RPSs will enable the success of historic missions such as Viking and Voyager, and more recent missions such as Cassini and New Horizons, to be carried forward into the future. William W. Hoover Ralph L. McNutt, Jr. Co-Chairs, Radioisotope Power Systems Committee ix
Acknowledgments This report has been reviewed in draft form by individuals chosen for their diverse perspectives and technical expertise, in accordance with procedures approved by the Report Review Committee of the National Research Council (NRC). The purpose of this independent review is to provide candid and critical comments that will assist the institution in making its published report as sound as possible and to ensure that the report meets institutional standards for objectivity, evidence, and responsiveness to the study charge. The review comments and draft manuscript remain confidential to protect the integrity of the deliberative process. We wish to thank the following individuals for their review of this report: William B. Adkins, Adkins Strategies, LLC, Carl A. Alexander, Battelle Memorial Institute, Jimmy L. Allison, Boeing Company (technical fellow), Mohamed S. El-Genk, University of New Mexico, Kathleen F. Harer, NASA and DOE (retired), Anthony K. Hyder, University of Notre Dame, E. Philip Muntz, University of Southern California, Zack T. Pate, World Association of Nuclear Operations (chair emeritus), and John Spencer, Southwest Research Institute. Although the reviewers listed above have provided many constructive comments and suggestions, they were not asked to endorse the conclusions or recommendations, nor did they see the final draft of the report before its release. The review of this report was overseen by Louis J. Lanzerotti, New Jersey Institute of Technology. Appointed by the NRC, he was responsible for making certain that an independent examination of this report was carried out in accordance with institutional procedures and that all review comments were carefully considered. Responsibility for the final content of this report rests entirely with the authoring committee and the institution.
Contents SUMMARY 1 1 THE PROBLEM 5 2 BACKGROUND 7 Why Space Exploration?, 7 Why Radioisotope Power Systems?, 7 Why 238Pu?, 8 NASA and DOE Roles and Responsibilities, 8 RPS Nuclear Safety, 11 References, 12 3 PLUTONIUM-238 SUPPLY 14 Foreign or Domestic 238Pu?, 14 How Much Do We Need?, 14 Plutonium-238 Production Process, 16 Immediate Action Is Required, 18 RPS Mission Launch Rate, 21 References, 23 4 RPS RESEARCH AND DEVELOPMENT 24 Program Overview, 24 Program Balance, 25 RPS System Capabilities, 26 Power System for the Outer Planets Flagship 1 Mission, 27 Development of a Flight-Ready ASRG, 27 RPS Facilities, 29 RPS Research and DevelopmentâSummary, 29 References, 30 LIST OF FINDINGS AND RECOMMENDATIONS 31 xi
xii CONTENTS APPENDIXES A Statement of Task 35 B Biographies of Committee Members and Staff 36 C NASAâs Projected Demand for 238Pu 40 D Comparison of 238Pu to Alternatives 43 E History of Space Nuclear Power Systems 46 F Briefings to the Committee 50 G Acronyms and Abbreviations 53
Tables, Figures, and Box TABLES 2.1 U.S. Spacecraft Using Radioisotope Power Systems, 9 2.2 RPS Contribution to Space Science and Exploration Missions, 10 3.1 NASAâs Demand for 238Pu, 2009-2028 (as of April 2008), 15 3.2 Best-Case Estimate of 238Pu Shortfall through 2028: 238Pu Demand Versus Supply Subsequent to Launch of Outer Planets Flagship 1, 19 D.1 Primary Emissions Produced by Radioisotopes with Half-lives of 15 to 100 Years, 44 D.2 Characteristics of 238Pu and 244Cm Isotope Fuels, 44 E.1 Radioisotope Power Systems for Space Exploration, 49 FIGURES S.1 Potential 238Pu demand and net balance, 2008 through 2028, 3 3.1 Potential 238Pu supply, demand, and net balance, 2008 through 2028, 20 3.2 Time line for reestablishing domestic 238Pu production and NASA mission planning, 2010 through 2028, assuming the Department of Energy starts work in fiscal year 2010, 22 4.1 Relative magnitude of key elements of NASAâs radioisotope power system program, 25 4.2 Performance of past, present, and future radioisotope power systems, 26 BOX 1.1 What Is a Radioisotope Power System?, 6 xiii