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Suggested Citation:"Front Matter." National Research Council. 1988. Space Science in the Twenty-First Century: Imperatives for the Decades 1995 to 2015, Overview. Washington, DC: The National Academies Press. doi: 10.17226/748.
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Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

SPACE SCIENCE IN THE TWENTY-FIRST CENTURY: IMPERATIVES FOR THE DECADES 1995 TO 2015 OVERVIEW Report of the Study Steering Group Space Science Board Commission on Physical Sciences, Mathematics, and Resources National Research Council NATIONAL ACADEMY PRESS Washington, D.C. 1988

National Academy Press · 2101 Constitution Avenue, N.W. . Washington, D. C. 20418 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 report has been reviewed by a group other than the authors according to procedures approved by a Report Review Committee consisting of members of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The National Academy of Sciences is a priorate, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific Ad 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. Frank Press 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. Robert M. White ~ 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. Samuel O. Thier 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 community of science and technology with the Academy's 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 government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Frank Press and Dr. Robert M. White are chairman and vice chairman, respectively, of the National Research Council. Support for this project was provided by Contract NASW 3482 between the National Academy of Sciences and the National Aeronautics and Space Administration. Library of Congress Catalog Card Number 87-43329 ISBN 0-309-03838-3 Printed in the United States of America First Printing, June 1988 Second Printing, May 1991

N AT I O N AL RES E ARC H CO U NC I L 2101 CON5T.ITUT1ON AVENUE OFFICE OF THE CHAIRMAN W^SHI>JCTON, D. C. X)d18 Dr. James Fletcher Administrator National Aeronautics and Space Administration Washington, DC 20546 Dear Dr. Fletcher: I am pleased to transmit Space Science Twentv- First Century: Imperatives for the Decades l99S to 201S, a report of the Space Science Board of the National Research Council. The report represents an impressive ef fort by a large number of scientists whose interests and expertise span the vast extent of space science. The Board charged the parti- cipants in the project to think broadly and creatively, and the product demonstrates clearly that they took this charge to heart. The several volumes of the report present a varied and exciting picture of opportunities in the space sciences in the future. I want to note two aspects of the report--and of the view of space sciences presented in it--both of which are considered in the document itself but which bear repeating here. Any portrayal of the future of space science presup- poses successful solutions to the severe problems that our nation's space science program faces today. The Challenger accident, coupled with our over-reliance on manned launch capabilities, has, to all intents and purposes, crippled our space science program by depriving us of access to space. The lessons of the past few years are painfully clear, and it is to be hoped that they will lead to a more balanced and resilient space program in the near and longer-term future. Particularly in light of current uncertainties, the findings and recommendations contained in these volumes probably constitute, in aggregate, a much larger space science program than can be realistically anticipated in the period of time examined in the study. While they are aware of this, the Board and study group do believe that the recommendations should be pursued at the appropriate time. There is no attempt in the report to establish priorities among the recommendations. As noted in the preface to the Overview volume, the Board felt that setting priorities "would not be appropriate at this time when we do not have the benefit of the knowledge we expect to gain from major missions now planned but not yet begun." nlE NATIONAL RESEARCH COUNCIL IS THE PR INCIPAL OPER^I INC SCENT OF DlE NOTIONAL ACADEMY OF SCIENCES AND THE NATIONAL A~E' OF EN~EERINC TO SERVE GOVERNMENT AND OTHER OR<;ANiZ^llONS. · -— lI1

I commend the report to you as a stimulating and chal- lenging description of the opportunities that lie before us in the space sciences. ~ Yours sin ~ ely, rank Press Chairman 1V

STEERING GROUP Thomas M. Donahue, University of Michigan, Chairman Don Anderson, California Institute of Technology D. James Baker, Joint Oceanographic Institutions, Inc. Robert Berliner, Pew Scholars Program, Yale University Bernard Burke, Massachusetts Institute of Technology A. G. W. Cameron, Harvard College Observatory George Field, Center for Astrophysics Herbert Friedman, Naval Research Laboratory DonaId Hunten, University of Arizona Francis Johnson, University of Texas at Dallas Robert Kretsinger, University of Virginia Stamatios Krimigis, Applied Physics laboratory Eugene Levy, University of Arizona Frank B. McDonald, NASA Headquarters John Naugle, Chevy Chase, Maryland Joseph M. Reynolds, The Louisiana State University Frederick Scarf, TRW Systems Park Scott Swisher, Michigan State University David Usher, Corned University James Van Allen, University of Iowa Rainer Weiss, Massachusetts Institute of Technology Dean P. Kastel, Study Director Ceres M. Rangos, Secretary or

TASK GROUP ON PLANETARY AND LUNAR EXP[O:RATION Donald Hunten, University of Arizona, Chairman Arden Albee, California Institute of Technology David C. Black, NASA Headquarters Jacques Blamont, CNES William Boynton, University of Arizona Robert A. Brown, Space Telescope Science Institute A. G. W. Cameron, Center for Astrophysics Thomas Donahue, University of Michigan Larry W. Esposito, University of Colorado Ronald Greeley, Arizona State University Eugene Levy, University of Arizona Harold Masursky, U.S. Geological Survey David Morrison, University of Hawaii at Manoa George Wetherill, Carnegie Institution of Washington Paul F. Uhlir, Staff Offlcer Anne L. Pond, Secretary ·. All

TASK G1tOUP ON SOLAR AND SPACE PHYSICS Frederick Scarf, TRW, Chairman Roger Me Bonnet, Agence Spati~e Europeene Guenter E. Brueckner, Naval Research Laboratory Alexander Dessler, Marshall Space Flight Center Thomas Holder, National Center for Atmospheric Research Sta~natios Krim~g~s, Johns Hopkins Universtiy Louis Lanzerotti, Bell Laboratories John Leibacher, National Solar Observatory Robert MacQueen, National Center for Atmospheric Research Car} E. McIlwam, University of California, San Diego Andrew Nagy, University of Michigan Eugene N. Parker, University of Chicago George Paulikas, Aerospace Corporation Christopher Russell, University of California at Los Angeles James Van Allen, University of Iowa Richard C. Hart, Staff Offlcer Carmela J. Chamberlain, Secretary · - ~ V111

TAS1[ GROUP ON ASTRONOMY AND ASTROPHYSICS Bernard Burke, Massachusetts Institute of Technology, Chairman James Roger Angel, University of Arizona Jacques Beckers, NOAO Advanced Development Program Andrea Dupree, Center for Astrophysics Carl E. Fichtel, NASA Goddard Space Flight Center George Field, Center for Astrophysics Riccardo Giacconi, Space Telescope Science Institute Jonathan Grindiay, Center for Astrophysics Martin Harwit, Cornell University Frank Low, University of Arizona Frank McDonald, NASA Headquarters Dietrich MuDer, University of Chicago M~noru Oda, ISAS Klaus Pinks, Max-Pl~c:k Institute for Plasma Physics Kenneth A. Pounds, University of Leicester Irwin Shapiro, Center for Astrophysics Susan Wyckoff, Arizona State University Richard C. Hart, Stag Offlcer Carmela J. Chamberlain, Secretary ix

TAS1[ GROUP ON FUNDAMENTAL PHYSICS AND CHEMISTRY Rainer Weiss, Massachusetts Institute of Technology, CmCha~rman Joseph M. Reynolds, The Louisiana State University, CmChaarman Peter Bender, University of Colorado A. L. Beriad, University of California RusseD Donnelly, University of Oregon Freeman Dyson, The Institute of Advanced Study William M. Far bank, Stanford University Robert Hofstadter, Stanford University George Homsy, Stanford University James banger, University of California John Naugle, Fairchild Space Company Rene PeDat, CNES Remo Ruffini, Universita di Roma Dudiey Saville, Princeton University John Robert SchriefFer, University of California Dean P. K=tel, Staff Director Ceres M. Tangos, secretary - x

TASK GROUP ON LIFE SCIENCES Scott Swisher, Michigan State University, Co-Chairman David Usher, Corned University, Co-Chairman Me~nrat Andreae, Florida State University Stanley Awramik, University of California, Santa Barbara Robert Berliner, Pew Scholars Program, Yale University William DeCampli, Stanford Medical Center James Ferris, Rensselaer Polytechnic Institute Robert Fowles, University of Utah Andrew KnoD, Harvard University Robert Kretsinger, University of Virginia Lynn Margul~s, Boston University Raymond Murray, Michigan State University Quentin Myrvik, Wake Forest University John Oro, University of Houston Tobias Owen, SUNY at Stony Brook Donald D. Turkey, Oregon Health Services University G. Donald Whedon, International Shrine Hospital David White, Florida State University Richard J. Wurtm~, Massachusetts Institute of Technology Richard Young, MATSCO Jay M. Goldberg, University of Chicago Harold Klein, The University of Santa Clara Joyce M. Purcell, Staff Offlcer Judith L. Estep, Secretary x~

SPACE SCIENCE BOARD Thomas M. Donahue, University of Michigan, Chairman Philip Abelson, American Association for the Advancement of Science Roger D. Blandford, California Institute of Technology Larry W. Esposito, University of Colorado Jonathan E. Gr~ndIay, Center for Astrophysics Donald Hall, University of Hawaii Andrew P. Ingersoll, California Institute of Technology William M. Kaula, NOAA Harold Klein, The University of Santa Clara John W. Leibacher, National Solar Observatory Michael Mendillo, Boston University Robert O. Pepin, University of Minnesota Roger J. Phillips, Southern Methodist University David Raup, University of Chicago Christopher T. RusseD, University of California, Los Angeles Blair D. Savage, University of Wisconsin John A. Simpson, Enrico Fermu Institute, University of Chicago George L. Siscoe, University of California, Loo Angeles L. Dennis Smith, Purdue University Darrell F. Strobel, Johns Hopkins University Byron D. Tapley, University of Texas at Austin Dean P. Kastel, StaffDirector Ceres M. Rangos, Secretary ·— X11

COMM[SSION ON PHYSICAL SCIENCES, MATHEMATICS, AND llESOUl1CES Norma Hackerma~, Robert A. Welch Foundation, Chairman George F. Carrier, Harvard University Dean E. Eastman, IBM Corporation Marye Anne Fox, University of Texas Gerhart EtriedIander, Brookhaven National Laboratory Lawrence W. Funkhouser, Chevron Corporation (retired) PhiBip A. Griffiths, Duke University J. Ross Macdonald, University of North Carolina, Chapel Hill Charles J. Mank=, Oklahoma Geological Survey Perry L. McCarty, Stanford University Jack E. Oliver, Cornell University Jeremiah P. Ostriker, Princeton University Observatory William D. Phillips, MaD~nckro~t, Inc. Denis J. Prager, MacArthur Foundation David M. Raup, University of Chicago Richard J. Reed, University of Washington Robert E. Sievers, University of Colorado Larry L. Smarr, Nations Center for Supercomput~ng Applications Edward C. Stone, Jr., California Institute of Technology Karl K. Turekian, Yale University George W. Wetherill, Carnegie Institution of Washington Irving Wladawsky-Berger, IBM Corporation Raphael G. Kasper, Executive Director Lawrence E. McCray, Associate Executive Director · -— X111

Preface Early in 1984, NASA asked the Space Science Board to un- dertake a study to determine the principal scientific issues that the disciplines of space science would face during the period from about 1995 to 2015. This request was made partly because NASA expected the Space Station to become available at the beginning of this period, and partly because the missions needed to im- plement research strategies precariously developed by the various committees of the board should have been launched or their de- velopment under way by that time. A two-year study was called for. To carry out the study the board put together task groups on earth sciences, planetary ~d lunar exploration, solar system space physics, astronomy and astrophysics, fundamental physics and chemistry (relativistic gravitation and m~crogravity sciences), and life sciences. Responsibility for the study was vested in a steering group whose members consisted of task group chairmen plus other senior representatives of the space science disciplines. To the boazd's good fortune, distinguished scientists from many countries other than the United States participated in this study. The task groups and the steering group held four joint study sessions beginning in the summer of 1984 and ending in January 1986. Individual task groups also scheduled workshops at other times. The steering group met from June 16 to June 20, 1986, at TV

the Woods Hole Study Center of the National Academy of Sciences to agree on the contents of the final overview report for the study. The findings and recornrnendations of the study are published in seven volumes: six task group reports and this overview report of the steering group. When the study began, the steering group encouraged the task groups to be imaginative in considering new directions for their disciplines. The intent was to challenge the participants to expand their horizons and to garner as many stim- ulating ideas as possible for future enterprises In space science. In providing this latitude for the task groups, the steering group felt that, since it was responsible for writing the official study report, it could not be bound initially to accept all the recommendations and findings of the task groups. The task group reports, there- fore, are ciassifiec] as resource documents for the steering group. Happily, at the study's conclusion, the steering group was able to accept nearly aD of the task group recommendations. The steer- ing group co~runends the task group reports to the reader for an understating of the challenges that confront the space sciences and the insights they promise for the next century. We gratefully acknowledge the valuable contribution made by the task group members during this Tensile study period. The official findings and recommendations of the study are those to be found in the steering group's overview. Obviously, with the delay in the space science program caused by the Challenger accident, the period specified in the original request by NASA (1995 to 2015) cannot be taken literally. The steering group believes that the longer term program it recom- mends for each discipline should logically be undertaken when the near-term program, currently being addressed in response to the science strategies developed by the committees of the Space Sci- ence Board, have been unplemented, whenever that may be and however long it takes to complete the entire agenda of science objectives. The steering group has deliberately chosen not to un- dertake a prioritization of its recommendations. This would not be appropriate at this tane when we do not have the benefit of the knowledge we expect to gain from major missions now planned but not yet begun. We expect the committees of the Space Science Board and internal NASA advisory groups at the appropriate time to establish the science priorities and to recommend the proper pace and sequence for new space science missions. After the study had begun, Congress mandated the formation XVI

of a National Commission of Space to propose goals for the na- tion's space program during the next 20 years. The commission published its report, entitled Pioneering the Space Frontier, before this study was completed. Since the expertise of our study group and its parent board is in science, it is not In our special competence to comment on the program recommended by the commission in its entirety. We certainly endorse its first major thrust: "Advancing our under- stand~ng of our planet, our solar system, and the universe, and the additional thrust of advancing technology. That part of the commi~sion's report entitled "Advancing Science" is altogether consonant with the recommendations of this report. Our colleagues and partners at NASA have supported our work fully. With their help we believe that we have prepared a sci- entific strategy for NASA to implement in the twenty-first century that wiD add luster to an already bright set of accomplishments. The hardworking stab of the Space Science Board headed by Dean Kastel, staff director and study director, deserves special recognition for their steadfast support and guidance in preparing this strategy. Thomas M. Donahue, Chairman Space Science Board ·. XV11

Contents 1 INTRODUCTION 1 2 EARTH SCIENCES: A MISSION TO PLANET EARTH 5 Background, 5 Earth as a Global System, 6 Scientific Themes, 9 Recornrnended Program: Pos~1995, 10 The Role of NASA ~ Earth Sciences, 12 National Coordination, 13 Conclusions, 14 3 PLANETARY AND LUNAR EXPLORATION Background, 15 Goals of Planetary Exploration, 16 Achievements of Planetary Exploration, 18 Future Planetary Exploration A Balanced Planetary Program, 20 Conclusion, 25 4 SOLAR SYSTEM SPACE PHYSICS Background, 27 The Sun, Solar Processes, and Variability, 29 The Sun-Earth System, the Magnetosphere, and the Aurora, 29 X1X 15 27

The Upper Atmosphere, 30 Magnetospheres of Other Planets and Comets, 31 Connections of Solar System Space Physics to Laboratory and Astrophysical Plasmas, 31 Nature of the Field, 32 Current Flight Projects, 32 Prospective Pre-1995 Missions, 33 Recommended Program: Pos~1995, 34 Conclusions, 35 5 ASTRONOMY AND ASTROPHYSICS Background, 37 Major Scientific Questions, 38 The Evolution of Space Astronomy, 41 Recommended Program: Pos~1995, 45 Cros~Links with Other Disciplines, 49 Conclusions, 49 6 FUNDAMENTAL PHYSICS AND CHEMISTRY: RELATIVISTIC GRAVITATION AND MICROGRAVITY SCIENCE Overview, 51 A. Relativistic Gravitation, 52 Background, 52 Tests of Genera] Relativity Theory In Weak Fields, 52 Principle of Equivalence, 53 Secular Change in the Gravitational Constant, 54 Gravitational Waves, 54 Pr - 1995 Program for Relativistic Gravitation, 55 Recommended Program for Relativistic Gravitation: Post-1995, 56 B. Microgravity Science, 57 Background, 57 Observation of States in Equilibrium, 57 Observation of States Destroyed by Gravity, 58 States Far from Equilibrium, 58 Conclusions and Recommendations for Microgravity Science, 58 7 LIFE SCIENCES Background, 60 xx 37 51 60

Life Science Goals and Major Questions, 63 Recommended Progrmn: Pos~1995, 69 8 INTERDISCIPLINARY STUDIES 9 HUMAN PRESENCE IN SPACE Space Age Science, 76 The Scope of Human Presence in Space; 77 10 INTERNATIONAL COOPERATION 11 PRECONDITIONS AND INFRASTRUCTURE XXI - 74 76 79 82

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