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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 International Cooperation for Mars Exploration and Sample Return 1 Introduction The goals of planetary exploration are to understand the origin and evolution of the solar system, how the planets formed, and how the planets evolved to their present states and environments. The history and evolution of Earth indicate that life can have profound effects on the development of a planet's surface and atmospheric environment. Parallel goals are to understand the chemical precursors of life and the conditions that led to the origin of life on Earth and to ascertain the prevalence of analogous prebiotic or biotic environments elsewhere. Altogether, planetary exploration seeks to answer questions that are fundamental to our understanding of our existence on Earth, as well as to the present state of our planetary environment and its evolution. These planetary questions have stimulated human thought and scientific investigation throughout history. They continue to be among the most basic and pressing of scientific questions today. Thus planetary exploration has been recognized as a fundamental element of the U.S. space program and as a source of great international prestige. Investigation of the terrestrial planets has been put forward by the Space Studies Board (SSB) as a principal focus of planetary exploration1; the importance of terrestrial planet studies has subsequently been reiterated in program implementation plans put forward by the National Aeronautics and Space Administration (NASA) 4,5 and by the SSB. 6 In the context of this focus, it is recognized that Mars occupies a special position as a target for intensive investigation. The triad of terrestrial planets—Earth, Mars, and Venus—has been a major target of investigation by both the United States and the USSR because these three terrestrial planets pose a particularly sharp set of scientific questions and because their proximity makes them attractive targets for investigation. Earth, Mars, and Venus are similar in their sizes, masses, compositions, and locations with respect to the Sun. Yet these planets have evolved to have widely (different surface (1 of 4) [6/18/2004 10:03:34 AM]

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Space Studies Board conditions in ways that are of special interest to human beings, whose existence and survival depend on the special surface conditions of Earth. Studies of these three planets have already revealed that terrestrial planet environments may change their states in highly unstable ways. It is possible that, at times past, the conditions on both Mars and Venus may have been more similar to present-day terrestrial conditions. It is important to understand the possible varieties and causes of changes in terrestrial planet environments, especially today, when human perturbations of Earth's environment are no longer negligible and are growing larger. In these three planets we observe three natural experiments in planetary evolution. One experiment produced the Earth, where abundant free water on its surface and in its atmosphere has enabled the origin and persistence of life. Another experiment produced Venus, where most of the outgassed volatiles remained in a carbon-dioxide-rich atmosphere but where the water apparently escaped. And the third experiment produced Mars, which either has lost part of its atmosphere or never had one of large substance, but which has undergone extraordinary environmental change. For these reasons, investigation of the triad of terrestrial planets with persistent atmospheres has very high scientific priority, The primary scientific objective of studying this group of terrestrial planets is to understand the reasons for their diverse evolutions and their very different present environments. An additional motivation for giving a high priority to the investigation of terrestrial planets is that such investigations will illuminate our understanding of the planet Earth. Early investigations of Mars, undertaken in the U.S. space program during the past 20 years, have revealled that that planet poses numerous profound questions about the behavior of terrestrial planets and their environments. Evidence of broad climatological changes, apparently encompassing ancient temperate episodes with flowing water as well as the cold dry conditions that we observe today, challenges our understanding of the behavior of planetary environments and raises questions about the stability of planetary environments, including that of Earth. Moreover, from a practical point of view, after Earth, Mars is the terrestrial planet most accessible to investigation, because of both its proximity and its relatively benign surface conditions. Altogether, the intensive investigation of Mars offers a broad spectrum of important scientific reward, technical challenge, and opportunity. The National Research Council's Space Studies Board has recommended that the next major phase of Mars exploration involve detailed in situ investigations of the surface of Mars and the return to Earth for laboratory analysis of selected martian surface and subsurface samples. 1 Mars sample return and intensive Mars surface investigation have been accepted by NASA as essential to accomplishing very- high-priority terrestrial planet scientific objectives within a balanced program of planetary and space science and have been included in NASA planning by NASA and its internal advisory panels. 4,5 In addition, Mars exploration is of wide scientific and technical interest in several other nations. 7 A Mars surface rover (2 of 4) [6/18/2004 10:03:34 AM]

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Space Studies Board project, recognized as a necessary element of a Mars sample return program, has been identified as a desirable candidate for joint NASA-European Space Agency (ESA) collaboration by the U.S. National Academy of Sciences-European Science Foundation Joint Working Group on Cooperation in Planetary Exploration.a The ESA has also expressed general interest in a broader program of cooperative Mars exploration and sample return. The USSR has announced national plans for an extensive program of Mars investigation that incorporates substantial international cooperation. The present Committee on Cooperative Mars Exploration and Sample Return was established at the request of NASA. The charge to the committee was to examine and report on the question of how Mars sample return missions might best be structured for effective implementation by NASA along with international partners. The committee considered alternatives ranging from scientific missions in which the United States would take a substantial lead, with international cooperation playing only an ancillary role, to missions in which international cooperation would be a basic part of the approach, with the international partners taking on comparably large mission responsibilities. The committee considered the scientific basis of such collaboration and the most mutually beneficial arrangements for constructing missions of separate supporting elements. Although the committee considered the possibility that the United States would play only a minor role while intensive Mars exploration was carried on by other nations, this alternative is not treated in detail in this report. The committee agreed with previous recommendations of the Space Studies Board as to the importance and priority of intensive Mars exploration and sample return and took as a premise the desirability of a high level of U.S. participation. The Joint Working Group on International Cooperation in Planetary Exploration also reported specific details of recommended candidate joint projects and made specific recommendations as to the types of cooperation that could serve as a basis of U.S.-European joint projects in several aspects of planetary exploration, including the investigation of Mars.8 The recommendations for U.S.-European cooperation in planetary exploration were based on the relatively long record of experience with various levels of cooperation between U.S. and European scientists and between NASA and the several European space agencies. Those recommendations also took into account the long tradition of open communication, travel, cooperation, and technical exchange that has existed between Western Europe and the United States. For reasons given in Chapter 2, the United States and the USSR occupy unique positions with respect to the intensive levels of exploration associated with the next steps of Mars exploration and Mars sample return. Because of this, the present study has focused on developing policy recommendations for possible cooperation between the United States and the USSR, specifically in the context of strongly stated interests by both nations in conducting intensive scientific explorations of Mars that include in situ investigations at Mars and the return of samples to Earth for laboratory analysis. The high scientific importance that is attached to such intensive studies of the planet Mars, the ambitious nature of the needed Mars (3 of 4) [6/18/2004 10:03:34 AM]

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Space Studies Board investigations, and the fact that the two leading spacefaring nations have both expressed strong interest in and have announced plans for Mars investigations create a strong motivation to explore possible means of cooperation in this historic and consequential endeavor. The scope of the present study and the recommendations in this report have purposefully been constrained to deal with those issues that are especially pertinent to the specific question of U.S.-USSR cooperation in a program of Mars investigations with sample return. A great many other issues and questions arise that are not dealt with in detail in this report. Many of these issues—including the pertinent scientific objectives and the detailed strategy of investigating Mars and collecting surface samples—have been addressed in previous scientific policy reports of the National Research Council 1,8 and in implementation plans of NASA and are not taken up further here. This report relies on those earlier recommendations to define the scientific context within which U.S.-USSR cooperation would take place. Last update 9/5/00 at 3:51 pm 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 (4 of 4) [6/18/2004 10:03:34 AM]