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PLANETARY EXPLORATION 1968 - 1975 Report of a Study by the Space Science Board 7- Washington, D C., June 1968 National Academy of Sciences - National Research Council // July 1968
Luis W. Allan H. Loren D. John W. Herbert John S. Francis William Donald B Alvarez Brown Carlson Find lay Friedman Hall S. Johnson M. Kaula Lindsley SPACE SCIENCE BOARD H. H. Hess, Chairman G.J.F. MacDonald Nicholas U. Mayall Courtland D. Perkins Richard W. Porter Leonard I. Schiff James A. Van Allen Donald U. Wise George P. Woollard Martin A. Pomerantz (ex officio) G. A. Derbyshire, Executive Secretary PLANETARY EXPLORATION STUDY PARTICIPANTS G.J.F. MacDonald, Chairman Charles A. Barth University of Colorado Allan H. Brown University of Pennsylvania Joseph W. Chamberlain Kitt Peak National Observatory Robert E Danielson Princeton University Von R. Eshleman Stanford University John V. Evans Massachusetts Institute of Technology, Lincoln Laboratory Richard Goody Harvard University H. H. Hess Princeton University Norman H. Horowitz California Institute of Technology William M. Kaula University of California (Los Angeles) Harold Masursky U. S. Geological Survey Thomas A. Mutch Brown University Norman F. Ness Goddard Space Flight Center Robert Phinney Princeton University John Reynolds University of California (Berkeley) I. Shapiro Massachusetts Institute of Technology William M. Sinton University of Hawaii Harold C. Urey University of California (San Diego) Wolf Vishniac University of Rochester Aaron C. Waters University of California (Santa Cruz) Donald U. Wise Franklin and Marshall College John A Wood Smithsonian Astrophysical Observatory Bruce N. Gregory, Study Director National Aeronautics and Space Administration Contributors: James R. Edberg Donald P. Hearth Robert S. Kramer Urner Liddel Milton A. Mitz Donald G. Rea
FOREWORD This is the report of a study convened by the Space Science Board to consider planetary exploration in the period from 1968 to 1975. The group reappraised the recommendations of the Board's 1965 Woods Hole Study in the light of advances in scientific knowledge and changing demands upon the nation's resources. The study was conducted during the week of June 10, 1968 under the chairmanship of Gordon J. F. MacDonald and involved 23 scientists repre- senting the spectrum of scientific interests in planetary studies. The recommendations of the group were presented to NASA management on the afternoon of June 16 and were discussed and endorsed by the Space Science Board at its meeting on June 24 and 25. The Space Science Board is grateful to those who participated in this study, to Bruce N. Gregory of the Space Science Board staff who ably directed the study, and to Miss Ann Wagoner, also of the staff, for her contributions to the report's publication. The Board acknowledges with appreciation the support of the National Aeronautics and Space Administration, which helped to make this study possible. H. H. Hess, Chairman Space Science Board -iii-
CONTENTS Foreword ill Summary of Principal Recommendations vii 1. Introduction 1 2. Recommendations 3 3. Planetary Atmospheres 19 4. Planetary Surfaces 27 5. Planetary Dynamics and Interiors 35 6. Particles, Fields, and Planetary Interactions with the Solar Wind 42 7. Exobiology 46 -v-
SUMMARY OF PRINCIPAL RECOMMENDATIONS 1. We recommend that the planetary exploration program be presented, not in terms of a single goal, but rather in terms of the contribution that exploration can make to a broad range of scientific disciplines (page 3). 2. We recommend that a substantially increased fraction of the total NASA budget be devoted to unmanned planetary exploration (page 3). 3. (a) We recommend that duplicate missions for a particular opportunity be undertaken only when a clear gain in scientific information will result from such double launches (page 4). (b) We recommend that NASA initiate now a program of Pioneer/IMF-class spinning spacecraft to orbit Venus and Mars at every opportunity and for exploratory missions to other targets (page 5). (c) We recommend the following larger missions to Mars: A Mariner orbiter mission in 1971, and a Mariner-type orbiter and lander mission, based on a Titan- Centaur, in 1973 (page 5). (d) We accord next priorities (in descending order) to a Mariner-class Venus-Mercury fly-by in 1973 or 1975, a multiple drop-sonde mission to Venus in 1975, and a major lander on Mars, perhaps in 1975 (page 6). 4. (a, b) Rather than attempt to define in detail payloads to be carried aboard high priority missions, we have selected several sample payloads (page 6). (c) We recommend that with regard to Mars and Venus, NASA continually re- assess, in the light of current knowledge of the planets, its program, methods, and mathematical model for meeting the internationally agreed objectives on planetary quarantine (page 11). 5. (a) We recommend strongly that NASA support radar astronomy as an integral part of its planetary program. In particular, we recommend that NASA fund the develop- ment and operation of a major new radar observatory to be used primarily for planetary investigation (page 12). (b) We recommend that NASA planetary program planning be closely coordinated with Earth-orbital telescopes being designed for the 1970's and with the infrared air- craft telescopes now under construction (page 13). (c) We recommend that the NASA program of ground-based optical planetary astronomy continue to receive strong support and that opportunities for planetary astro- nomical investigations be increased by: (1) Construction of an intermediate sized optical telescope in the Southern Hemisphere (2) Construction of an infrared telescope employing a very large collecting area and permitting interferometric measurements at a dry site (3) Development of new infrared devices, including improved detectors and high resolution interferometers (page 14) (d) We recommend that steps be taken to facilitate the analysis by qualified investigators of the data secured by the photographic planetary patrol (page 14). -vii-
6. (a) We recommend that NASA openly solicit participation in all future plan- etary missions by the issuance of flight opportunity announcements with adequate time for response from the scientific community (page 15). (b) We recommend that NASA develop a summer institute program expressly de- signed to introduce interested scientists and engineers to the science, technology, and administration of the planetary program (page 15). 7. We recommend that those resources currently intended for support of manned planetary programs be reallocated to programs for instrumented investigation of the planets (page 16). 8. We recommend a coordinated effort involving representatives of NASA, the Department of State, and the National Academy of Sciences, for the purpose of contact- ing knowledgeable Soviet scientists in an informal way with regard to the possibility of joint planning of planetary exploration (page 16). -viii-