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Space Studies Board Search: Jump to Top NewsJump to Science in the Subscribe to our FREE e- Headlines newsletter! NATIONAL ACADEMY OF SCIENCES NATIONAL ACADEMY OF ENGINEERING INSTITUTE OF MEDICINE NATIONAL RESEARCH COUNCIL June 18, 2004 Current Operating Status 1990 Update to Strategy for Exploration of the Inner Planets Appendix A Complete List of Recommendations Made in the 1978 Report* SCIENTIFIC GOALS, SEQUENCE, AND STRATEGY Levels of Investigation, Goals, and Mission Techniques In order to provide more specific guidance to achieve the general strategy goals of planetary exploration, primary objectives, which are the principal basis for defining a mission, and secondary objectives, which greatly enhance the value of a mission, are presented. All specific missions will consist of both kinds of objectives. (p. 7) We reaffirm our earlier suggestion that NASA assess the acquisition procedures so that this distinction in objectives is apparent in the choice and management of experiments and Principal Investigators. (pp. 7-8) We therefore recommend that an assessment of mission operations, including spacecraft control and scientific instrument and data management and the design and management of software control systems, be studied by the Agency at the earliest possible time and the evaluation be presented to the Committee. (p. 8) Present Strategy As a consequence, the inner-solar-system strategy that we propose, like its counterpart for the outer solar system, is very conservatively paced and recommends only those goals that are of the highest importance and that can be achieved only by planetary encounter by spacecraft. (p. 9) For the next decade there should be a shift in emphasis toward systematic exploration with emphasis on selected planets, but with some continuing level of reconnaissance to parts of the solar system where our ignorance is greatest and the opportunity for new discovery is large. (p. 9) http://www7.nationalacademies.org/ssb/innerappenda.html (1 of 11) [6/18/2004 10:07:25 AM]

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Space Studies Board It remains the unanimous view of the Committee "that planetary exploration will continue to be an area of major scientific importance over the next decade and that continuing vigorous activity in this field is fully justified." (p. 9) Role Of International Cooperation in Planetary Exploration We recommend that an effective mechanism be established by the United States and the Soviet Union for: (a) The establishment of active open working relationships between Soviet and American scientists so as to discuss the scientific problems and to understand the nature and quality of the scientific experiments that might be carried out; (b) The mutual identification of important scientific goals that are of a substantial nature; (c) The early reciprocal communication between the United States and Soviet Union of the specific scientific objectives, both current and planned, in the area of planetary exploration; (d) The establishment of concurrent commitments by both nations to achieve the goals in selected areas of mutual interest utilizing the agreed upon scientific objectives; (e) The coordination of missions to a planet with full disclosure of mission planning and objectives so as to optimize the scientific contributions of both nations; (f) The establishment of true cooperation between both nations through a reciprocal arrangement that allows the incorporation of significant scientific experiments by both parties on the same spacecraft; and (g) The timely communication and exchange of information both during and after completion of a mission. (p. 12) We therefore recommend that progress in carrying out the above functions in planetary exploration be reviewed and assessed annually by segments of both governments. We request that the SSB be briefed on the results of the review so that progress in coordination and cooperation may be properly evaluated in the SSB yearly study of the Space Sciences Program. (p. 12) We recommend that scientific planning, mission coordination, and cooperation between the United States and the Soviet Union be directed to those areas of planetary exploration where both nations have a vigorous and sustained effort and when the relative scientific strength and technological capabilities are mutually complementary in order to realize the maximum interest and scientific benefit. (p. 14) http://www7.nationalacademies.org/ssb/innerappenda.html (2 of 11) [6/18/2004 10:07:25 AM]

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Space Studies Board Launch Capabilities for Planetary Exploration We recommend that NASA adopt. a policy that places the planning and development of launch capabilities for unmanned space exploration in a 10- to 20- year perspective and that focuses on the requirements of our long-term objectives. (p. 14) We recommend that every effort be made to keep development of the Shuttle orbiter and a high-energy IUS on its nominal schedule. (p. 15) "In the 1975 SSB report it was recommended that any intermediate upper stage (IUS) considered for transearth payloads have at least the same capability with regard to spacecraft payload and injection energy as presently exists and be sufficient to carry 500-kg payloads with a C3 of 150 km2/sec2, payloads of 2000 kg at C3 of 90 km2/sec2, and payloads of more than 7000 kg for low C3." (p. 16) In the 1975 report, the Committee endorsed the ongoing efforts by NASA to reduce the weight and cost of standardized available spacecraft without a corresponding reduction in capability using new developments in technology. (p. 17) We recommend that a comparative assessment be carried out of solar electronic propulsion (SEP) design options in terms of feasibility, cost-effectiveness, and ability to meet the scientific objectives of solar-system exploration over the next two decades. The assessment should take into account currently stated objectives, and major emphasis should be given to the search for currently undiscovered exploration opportunities that may become available as a result of new propulsion capabilities. (pp. 18-19) Earth-Based and Earth Orbital Observations In the 1975 report, the Committee recommended that the adequacy of NASA support for the earth-based optical and radar programs, including aircraft and balloons for planetary observations, be reviewed regularly. The Committee was . unable to conduct this review during its 1977 schedule but now recommends that this review be conducted no later than November 1978. (p. 20) The order-of-magnitude improvement in spatial resolution available by use of the Space Telescope (ST), as well as access to wavelength regions unavailable from ground-based observatories, led us last year to "strongly recommend that a significant portion of the LST schedule be made available for planetary studies and that NASA begin immediate development of instruments that are oriented toward planetary studies for the LST and for other Shuttle deliverable payloads." COMPLEX wishes to reaffirm this view and to recommend further that the scheduling of ST observations be based on the potential scientific return from each proposed observational program with due regard for planetary mission planning and that the group charged with allocating telescope time be representative of the diverse interests of potential users. (p. 20) http://www7.nationalacademies.org/ssb/innerappenda.html (3 of 11) [6/18/2004 10:07:25 AM]

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Space Studies Board Planetary Quarantine Standards The Committee ... recommends that NASA conduct an overall review of its planetary quarantine policy and the policy for return and handling of samples from other planets to the earth in the light of our knowledge of these planets and in consonance with the terms of Article IX of the Outer Space Treaty. (p. 23) THE INNER PLANETS Strategy for Study of Inner Solar System: 1977-1987 As a statement of basic policy, the Space Science Board has defined the primary goals for investigation of the solar system. The primary goals are to determine the composition, structure, and environment of the planets and their satellites in order to define the present morphology and dynamics of the solar system and with the purpose of making major steps in understanding the processes by which the planets formed from the solar nebula and how they have evolved with time and how the appearance of life in the solar system is related to the chemical history of the system. The investigation of the interplanetary and interstellar medium is considered an intrinsic part of such an endeavor. (p. 31) The Committee recommends that there should be a shift in emphasis toward systematic exploration of selected, planets. The Committee also believes that some level of reconnaissance should be continued in accessible regions where our ignorance is greatest and where the opportunity of new discovery is large. (p. 31) The Committee concludes that exploration of the inner solar system will be an undertaking of major scientific importance well beyond the next decade. (p. 32) We have identified selected planets as the principal targets for investigation over the next decade in order adequately to fulfill the primary scientific goals enunciated by the Board and guarantee scientific advances in these areas rather than attempt to bring forward to a uniform level of exploration all the objects in the inner solar system. (p. 32) On a time scale of two decades it is our view that the general level of exploration for all the planets of the inner solar, system should be brought into balance: (p. 32) The Committee has concluded that observation and measurement of the morphologic, physical, and chemical character of Mars, Venus, Mercury, and the moon on a global sole are of high general scientific importance and are basic, to all planetological studies. (p. 33) COMPLEX recommends that the triad of terrestrial planets, Earth, Mars, and Venus, should :receive the major focus in exploration of the inner solar system for the next decade. The ultimate goal in this exploration is to understand the present http://www7.nationalacademies.org/ssb/innerappenda.html (4 of 11) [6/18/2004 10:07:25 AM]

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Space Studies Board state and evolution of terrestrial planets with atmospheres. The comparative planetology of these bodies is a key to the understanding of the formation of the earth, its atmosphere and oceans, and the physical and chemical conditions that lead to the origin and evolution of life. (p. 34) The atmosphere-free terrestrial planets, Mercury and the moon, are complementary bodies of high scientific interest: (p. 34) The moon must remain an important object of exploration, which should receive strong consideration during the decade. (p. 35) Steps should be made to prepare for the investigation of Mercury after definition of an adequate propulsion capability and in advance of availability of the system. (p. 35) Subsequent to the development of an adequate transportation system, it is the view of COMPLEX that more substantial resources should be diverted toward the accomplishment of the major objectives of planetary exploration. (p. 35) Policy Considerations for Sample Return In order to carry out an adequate program of exploration of the solar system, there will be a need to return several times to some planets with different spacecraft carrying different experiments, cover a period of two decades. (p. 40) Conclusion, Summary, and Recommendations As a result of this examination, COMPLEX recommends the following: 1. Sample return from solar-system bodies should be considered a mission technique within the framework of a continuing program of scientific exploration and not a terminal, long-term goal. 2. Studies should be initiated to develop the special technology for such sample returns, with the moon, Mars, and Venus being examples of grime candidates for such sample return. 3. In situ investigations should continue to be a major mission mode for planetary exploration. 4. Efforts should be undertaken (as described in Chapter 6) to identify and develop the more advanced scientific instrumentation and manipulative techniques needed for the scientific objectives of future in situ planetary investigations. (p. 41) The Role of Global Maps A global map or image of the surface of a planet at good resolution is considered to http://www7.nationalacademies.org/ssb/innerappenda.html (5 of 11) [6/18/2004 10:07:25 AM]

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Space Studies Board be a major scientific contribution and is basic to any advance in the understanding of the terrestrial planets. (p. 42) We do not wish to imply that global images at increasingly high resolutions are the means for continuing planetary exploration, but rather that an adequate resolution global image provides a fundamental framework for carrying out the specific analytic experiments on planetary bodies. The quantitative, analytic, and observational experiments must undoubtedly be the major means of scientific advance in an era of intensive exploration. (p. 43) Objectives for Mars We recommend that intensive study of Mars by spacecraft be achieved within the period 1977-1987. (p. 43) Primary Objectives In summary, the primary objectives in order of scientific priority for the continued exploration of Mars are (1) the intensive study of local areas (a) to establish the chemical, mineralogical, and petrological character of different components of the surface material, representative of the known diversity of the planet; (b) to establish the nature and chronology of the major surface forming processes; (c) to determine the distribution, abundance, and sources and sinks of volatile materials, including an assessment of the biological potential of the Martian environment, now and during past epochs; (d) to establish the interaction of the surface material with the atmosphere and its radiation environment; (2) to explore the structure and general circulation of the Martian atmosphere; (3) to explore the structure and dynamics of Mars's interior; (4) to establish the nature of the Martian magnetic field and the character of the upper atmosphere and its interaction with the solar wind; (5) to establish the global chemical and physical characteristics of the Martian surface. These objectives are multiply connected. (p. 44) Strategy for Mars ... the global and in situ studies of the planet and the return of Martian material are complementary components of an overall program of investigation; each of the components is separately necessary. (p. 49). We note ... that although a specific sequence of investigations, namely global and in situ studies followed by sample return, is desirable, it is not necessary. (p. 49) We ... recommend that detailed exploration, on both global and local scales, of the diverse environments of Mars for purposes of understanding surface, near-surface, and atmospheric processes is a worthy goal in its own right and should be accomplished within the next decade. (p. 49) http://www7.nationalacademies.org/ssb/innerappenda.html (6 of 11) [6/18/2004 10:07:25 AM]

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Space Studies Board We ... reaffirm our view that the return of unsterilized surface and subsurface samples to Earth is a major technique for the exploration of Mars. (p. 50) Objectives for Venus The Committee ... recommends that there be continued exploration of Venus by spacecraft during the next decade. (p. 55) Primary Objectives The primary objectives of the exploration of Venus during the period 1977-1987, beyond the Pioneer Venus mission, in order of importance, are (1) to obtain a global map of the topography and morphology of its surface at sufficient resolution to allow identification of the gross processes that have shaped the surface, (2) to determine the major chemical and mineralogical composition of the surface material, (3) to determine the concentrations of photochemically active gases in the 65-135 km altitude region, and (4) to investigate the physical and chemical interactions of the surface with the atmosphere and the composition and formation of atmospheric aerosols. (p. 57) We further recommend that some , images be taken of a limited number of selected regions at a substantially higher resolution than indicated above. (p. 57) The Committee has considered some possibilities and concludes that a serious study effort of the technology of instruments operating at Venusian surface temperatures and pressures must be undertaken before any particular approach is recommended. The substantial effort should be initiated in this area at the earliest possible time. (p. 58) Secondary Objectives COMPLEX believes that acquisition of seismic data from Venus should be maintained as a visible and highly desirable goal (p. 58) We recommend that preliminary studies be undertaken to determine the technical feasibility of returning samples of materials from the surface of Venus in order to ascertain the significance of this technique in developing an effective strategy for Venusian exploration over a time period of 20 years. (p. 59) Strategy and U.S.-USSR Cooperation It is the view of this Committee that continued scientific exploration of Venus offers an ideal arena for cooperation between the Soviet Union and the United States. We recommend that cooperative efforts be undertaken, according to the precepts set forth earlier in this report. (p. 59) Thus we recommend that a first U.S.-USSR collaboration proceed through the http://www7.nationalacademies.org/ssb/innerappenda.html (7 of 11) [6/18/2004 10:07:25 AM]

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Space Studies Board independent development of complementary experiments to be flown on a single spacecraft and plan for an early collaborative launch. (p. 60) Studies of Venus will make a crucial contribution to our understanding of the behavior and evolution of terrestrial environments. As a result, studies of Venus must be pursued vigorously regardless of the fate of attempts to make it a cooperative endeavor. (p. 60) Objectives for Mercury Scientific Objectives The primary planetary objectives in the exploration of Mercury for the period 1977- 1987 are to determine the chemical composition of the planet's surface on both a global- and regional scale, to determine the structure and state of the planet's interior, and to extend the coverage and improve the resolution of orbital imaging. (p. 68) Imaging Secondary planetary objectives of Mercury explorations are (1) further exploration of Mercury's magnetosphere and internal magnetic field, (2) measuring global heat flow, and (3) conducting gravity and topographic surveys of the planet. (p. 69) Conclusion We recommend that the planet then be included as an element in the sequence later in the decade and that the objectives as stated be adopted as the guideline for mission planning to implement the strategy, but with the proviso that initiating such a mission does not inhibit or detrimentally affect the primary emphasis on the triad Earth-Mars-Venus. (p. 71) Objectives for the Moon Scientific Objectives The primary scientific objectives for exploration of the moon by spacecraft in the period 1977-1987, in order of importance, are (1) to determine the chemistry of the lunar surface on both a global and regional scale; (2) to determine the surface heat flow on both a global and a regional scale; and (3) to determine the nature of any central metallic core in the moon. (p. 72) U.S.-USSR Cooperation We recommend that formal negotiations to explore the possibility of such coordinated lunar missions be initiated. (p. 74) http://www7.nationalacademies.org/ssb/innerappenda.html (8 of 11) [6/18/2004 10:07:25 AM]

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Space Studies Board Fields and Particles for Inner Solar System We recommend that the determination of the strength and character of the internal magnetic fields (both global fields and, where possible, small-scale remanent fields) be an important goal in the exploration of planetary bodies. (p. 75) We recommend that both cruise and orbiting phases of planetary missions be utilized for the conduct of important interplanetary and solar measurements when such an approach offers a significant increment over other available techniques and with due regard for a balanced approach to the first-order goals of such missions. (p. 76) The Committee regards an understanding of the fundamental processes governing the solar wind's interaction with planets as a major goal of solar-system exploration and recommends that a global characterization be obtained of each planet's interaction with the solar wind. (p. 76) Minor Bodies Investigations Meteorites COMPLEX strongly recommends continued intensive studies on meteorites as a parallel effort to the study of lunar samples, to earth-based observations of the solar system, and to space missions in the study of the planetary system. (p. 81) Conclusions In order to develop properly the scientific objectives and the relative place that direct exploration of these objects should have in the overall strategy, as separate bodies and as a class of objects, COMPLEX recommends that a special study tie carried out during the next year. (p. 81) COMPLEX calls attention to its 1975 recommendation "that efforts be directed toward establishing the nature and quality of scientific experiments that could yield important data in a comet encounter so that the role of a comet investigation can be properly assessed in the framework of the current strategy." (p. 81) SCIENTIFIC INSTRUMENTATION DEVELOPMENT We recommend that a mechanism be established by NASA to bring this knowledge to bear on planetary problems more effectively. Instrumentation studies, organized by NASA, which focus on specific instrument requirements and on present and future problem areas, would be an effective first effort. (p. 86) POSTMISSION DATA ANALYSIS AND SUPPORTING RESEARCH We ... recommend that NASA establish a vigorous and ongoing program of data http://www7.nationalacademies.org/ssb/innerappenda.html (9 of 11) [6/18/2004 10:07:25 AM]

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Space Studies Board analysis and synthesis, which is designed to foster interdisciplinary and comparative planetological research. (p. 89) We further recommend that NASA arrange for each mission science team to provide within a reasonable time frame a comprehensive report of its experiments and experimental results along with extended interpretations of these observations. (p. 89) EVALUATION OF PROPOSED PROGRAMS Interdisciplinary Scientist Statement COMPLEX unanimously agrees that every proposed planetary mission should follow the lead of Atmosphere Explorer and Pioneer Venus in having interdisciplinary scientists appointed to the mission Science Steering Group. (p. 91) STATUS OF EXISTING PROGRAMS Viking-Extended Mission COMPLEX recommends that the meteorology and imaging experiments on both landers and the seismometer on Lander 2 be continuously monitored and that the ranging to the Viking landers be continued for as long as possible. (p. 93) COMPLEX recommends that NASA maintain adequate ground support (personnel, tracking, computers, and image processing facilities) for the lifetime of the orbiters to ensure a maximum return of imaging data. (p. 93) The Committee recommends that special emphasis be given to laboratory studies aimed at deciphering the data obtained by Lander biology experiments. (p. 94) COMPLEX recommends that full advantage be taken of opportunities during the Viking Extended Mission to carry out a series of close encounters with the outer satellite, Deimos, in order to determine its mass and mean density. (p. 94) Pioneer 11 The value of the Pioneer 11 scientific role in exploring the outer solar system led COMPLEX to recommend in 1975 that "the coverage of Pioneer 11 be restored to a sufficient level by mid-1979 in order to optimize the science return at the Saturn encounter." (p. 96) Role of Lunar Samples and Data in Planetary Science We view lunar sample research and lunar data analysis and synthesis as essential elements of planetary studies and therefore recommend that these elements continue to receive substantial support as an integral and unique element of the http://www7.nationalacademies.org/ssb/innerappenda.html (10 of 11) [6/18/2004 10:07:25 AM]

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Space Studies Board exploration of the inner solar system. (p: 97) *Excerpted from Strategy for Exploration of the Inner Planets: 1977-1987 (National Academy of Sciences, Washington, D.C., 1978). Last update 9/26/00 at 3:57 pm Site managed by Anne Simmons, Space Studies Board Site managed by the SSB Web Group. To comment on this Web page or report an error, please send feedback to the Space Studies Board. Subscribe to e-newsletters | Feedback | Back to Top Copyright © 2004. National Academy of Sciences. All rights reserved. 500 Fifth St. N.W., Washington, D.C. 20001. Terms of Use and Privacy Statement http://www7.nationalacademies.org/ssb/innerappenda.html (11 of 11) [6/18/2004 10:07:25 AM]