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The Role of Small Missions in Planetary and Lunar Exploration The Role of Small Missions in Planetary and Lunar Exploration NOTICE MEMBERSHIP PREFACE EXECUTIVE SUMMARY CHAPTER 1 CHAPTER 2 Committee on Planetary and Lunar Exploration CHAPTER 3 Space Studies Board CHAPTER 4 Commission on Physical Sciences, CHAPTER 5 Mathematics, and Applications APPENDIX National Research Council NOTICE MEMBERSHIP PREFACE file:///C|/SSB_old_web/smlmenu.html (1 of 3) [6/18/2004 1:46:35 PM]

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The Role of Small Missions in Planetary and Lunar Exploration EXECUTIVE SUMMARY 1. BACKGROUND AND CURRENT ENVIRONMENT Planetary Explorer Planetary Observer Lunar Scout Clementine Discovery and Mars Surveyor References 2. THE SMALL-MISSION CONCEPT Explorers in Astrophysics, Space Physics, and Earth Sciences Small Missions in Planetary Exploration Relationship to Integrated Strategy The Need for a Balanced Program in Planetary and Lunar Exploration Attributes for an Effective Small-Missions Program for Planetary Exploration References 3. TECHNOLOGICAL AND PROGRAMMATIC ASPECTS Cost of Capable Small Missions The Need to Establish a Program Risk Philosophy Infrastructure Supporting Technology Subsidiary Goals Technology Education International Cooperation Program Issues Mission Operations Data Analysis and Archiving References 4. MANAGEMENT STRUCTURE AND PROCEDURES Selection Criteria and Procedures Management Practices: Approach, Cost Control, and Roles Review and Oversight Descoping and/or Cancellation References 5. RECOMMENDATIONS file:///C|/SSB_old_web/smlmenu.html (2 of 3) [6/18/2004 1:46:35 PM]

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The Role of Small Missions in Planetary and Lunar Exploration Reference APPENDIX: MISSIONS MENTIONED IN THIS REPORT NATIONAL ACADEMY PRESS, 1995 Last update 5/26/00 at 9:21 am Site managed by Anne Simmons, Space Studies Board The National Academies Current Projects Publications Directories Search Site Map Feedback file:///C|/SSB_old_web/smlmenu.html (3 of 3) [6/18/2004 1:46:35 PM]

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The Role of Small Missions in Planetary and Lunar Exploration: Notice The Role of Small Missions in Planetary and Lunar Exploration 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 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. Bruce Alberts is president of the National Academy of Sciences. REPORT MENU NOTICE The National Academy of Engineering was established in 1964, under the charter MEMBERSHIP of the National Academy of Sciences, as a parallel organization of outstanding PREFACE engineers. It is autonomous in its administration and in the selection of its EXECUTIVE SUMMARY members, sharing with the National Academy of Sciences the responsibility for CHAPTER 1 advising the federal government. The National Academy of Engineering also CHAPTER 2 sponsors engineering programs aimed at meeting national needs, encourages CHAPTER 3 education and research, and recognizes the superior achievements of engineers. CHAPTER 4 Dr. Harold Liebowitz is president of the National Academy of Engineering. CHAPTER 5 APPENDIX 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. Kenneth I. Shine 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 file:///C|/SSB_old_web/smlnot.html (1 of 3) [6/18/2004 1:46:54 PM]

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The Role of Small Missions in Planetary and Lunar Exploration: Notice 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. Bruce Alberts and Dr. Harold Liebowitz are chairman and vice chairman, respectively, of the National Research Council. Support for this project was provided by Contract NASW 4627 between the National Academy of Sciences and the National Aeronautics and Space Administration. Cover: Diagram of the Near-Earth Asteroid Rendezvous spacecraft. Copies of this report are available from Space Studies Board National Research Council 2101 Constitution Avenue, N.W. Washington, D.C. 20418 Copyright 1995 by the National Academy of Sciences. All Rights Reserved. Printed in the United States of America file:///C|/SSB_old_web/smlnot.html (2 of 3) [6/18/2004 1:46:54 PM]

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The Role of Small Missions in Planetary and Lunar Exploration: Membership The Role of Small Missions in Planetary and Lunar Exploration Membership Committee on Planetary and Lunar Exploration JOSEPH A. BURN,* Cornell University, Chair RONALD GREELEY, Arizona State University, Continuing Chair JAMES ARNOLD, University of California, San Diego FRANCES BAGENAL, University of Colorado GEOFFREY A. BRIGGS,* NASA Ames Research Center MICHAEL H. CARR,* U.S. Geological Survey PHILIP R. CHRISTENSEN, Arizona State University RUSSELL DOOLITTLE, University of California, San Diego JAMES L. ELLIOT,* Massachusetts Institute of Technology JOHN F. KERRIDGE,** University of California, San Diego BARRY H. MAUK,* Applied Physics Laboratory WILLIAM B. MCKINNON,* Washington University REPORT MENU EUGENE SHOEMAKER, U.S. Geological Survey NOTICE DARRELL F. STROBEL, Johns Hopkins University MEMBERSHIP ALAN F. TOKUNAGA, University of Hawaii PREFACE GEORGE W. WETHERILL,** Carnegie Institution of Washington EXECUTIVE SUMMARY ROGER YELLE, University of Arizona CHAPTER 1 MARIA T. ZUBER, John Hopkins University CHAPTER 2 CHAPTER 3 Staff CHAPTER 4 CHAPTER 5 APPENDIX DAVID H. SMITH, Executive Secretary ALTORIA B. ROSS, Senior Program Assistant ERIN C. HATCH, Research Assistant _________________ *Term ended in 1995. **Term ended in 1994. file:///C|/SSB_old_web/smlmem.html (1 of 4) [6/18/2004 1:47:08 PM]

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The Role of Small Missions in Planetary and Lunar Exploration: Membership SPACE STUDIES BOARD CLAUDE R. CANIZARES, Massachusetts Institute of Technology, Chair JOHN A. ARMSTRONG, IBM Corporation (retired) LAWRENCE BOGORAD, Harvard University JOSEPH A. BURNS,* Cornell University JOHN J. DONEGAN, U.S. Navy (retired) ANTHONY W. ENGLAND, University of Michigan DANIEL J. FINK, D.J. Fink Associates, Inc. MARTIN E. GLICKSMAN, Rensselaer Polytechnic Institute RONALD GREELEY, Arizona State University BILL GREEN, former member, U.S. House of Representatives HAROLD J. GUY,* University of California at San Diego Medical Group NOEL W. HINNERS, Lockheed Martin Astronautics JANET G. LUHMANN, University of California at Berkeley JOHN H. McELROY, University of Texas at Arlington ROBERTA BALSTAD MILLER, Consortium for International Earth Sciences Information Network BERRIEN MOORE III, University of New Hampshire MARY JANE OSBORN, University of Connecticut SIMON OSTRACH, Case Western Reserve University CARLÉ M. PIETERS, Brown University JUDITH PIPHER,* University of Rochester MARCIA J. RIEKE, University of Arizona ROLAND W. SCHMITT, Clifton Park, New York JOHN A. SIMPSON, University of Chicago ARTHUR B.C. WALKER, JR.,* Stanford University MARC S. ALLEN, Director ________________ *Former member. COMMISSION ON PHYSICAL SCIENCES, MATHEMATICS, AND APPLICATIONS ROBERT J. HERMANN, United Technologies Corporation, Chair STEPHEN L. ADLER, Institute for Advanced Study, Princeton PETER M BANKS, Environmental Research Institute of Michigan SYLVIA T. CEYER, Massachusetts Institute of Technology L. LOUIS HEGEDUS, W.R. Grace and Co. JOHN E. HOPCROFT, Cornell University RHONDA J. HUGHES, Bryn Mawr College SHIRLEY A. JACKSON, Rutgers University KENNETH I. KELLERMANN, National Radio Astronomy Observatory KEN KENNEDY, Rice University file:///C|/SSB_old_web/smlmem.html (2 of 4) [6/18/2004 1:47:08 PM]

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The Role of Small Missions in Planetary and Lunar Exploration: Membership HANS MARK, University of Texas at Austin THOMAS A. PRINCE, California Institute of Technology JEROME SACKS, National Institute of Statistical Sciences L.E. SCRIVEN, University of Minnesota LEON T. SILVER, California Institute of Technology CHARLES P. SLICHTER, University of Illinois at Urbana-Champaign ALVIN W. TRIVELPIECE, Oak Ridge National Laboratory SHMUEL WINOGRAD, IBM T.J. Watson Research Center CHARLES A. ZRAKET, Mitre Corporation (retired) NORMAN METZGER, Executive Director Last update 5/26/00 at 9:43 am Site managed by Anne Simmons, Space Studies Board file:///C|/SSB_old_web/smlmem.html (3 of 4) [6/18/2004 1:47:08 PM]

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The Role of Small Missions in Planetary and Lunar Exploration: Preface The Role of Small Missions in Planetary and Lunar Exploration Preface The Committee on Planetary and Lunar Exploration advises the Space Studies Board on the entire range of planetary science topics; these include laboratory analytical and computational investigations, ground-based observations, and space missions. The disciplinary scope of its advice comprises geophysics, the atmospheric sciences, exobiology, particles and fields, planetary astronomy, and the search for planets around other stars. Planetary missions of relatively low cost (<$150 million [FY 1992 dollars] excluding launch and mission operations), having both limited development schedules and measurement objectives, have been proposed as an effective means of achieving planetary science goals. Solar system missions of this size include Clementine (a Department of Defense/NASA technology demonstration mission that in early 1994 made extensive measurements of the Moon but was aborted before a planned flyby of asteroid 1620 Geographos) and Near-Earth REPORT MENU Asteroid Rendezvous (NEAR), approved for launch in early 1996; Mars NOTICE Pathfinder (a technology demonstration mission to land a payload on Mars), MEMBERSHIP being developed for a late 1996 launch, is of similar size but is somewhat PREFACE different in character. According to NASA's plans, the last two missions, which EXECUTIVE SUMMARY received new starts in the FY 1994 budget, would be the first in a continuing CHAPTER 1 program, called "Discovery." This document calls missions of this scale "small CHAPTER 2 missions." Even though its components are of a comparable size, Mars CHAPTER 3 Surveyor—a series of focused missions, including landers and orbiters—is not CHAPTER 4 addressed in depth in this report because at least the first few flights, while low- CHAPTER 5 cost, will be carried out much like previous NASA missions (i.e., will not be led by APPENDIX a principal investigator [PI]). Given that the proposed mode of operation of small missions is different from that previously employed by NASA's Solar System Exploration Division, the Space Studies Board charged its Committee on Planetary and Lunar Exploration (COMPLEX) to address a number of issues associated with small missions. Prime among these issues was to examine the degree to which small missions can achieve priority objectives in the lunar and planetary sciences. The study began with a meeting in Washington, D.C., in December 1993. file:///C|/SSB_old_web/smlpref.html (1 of 3) [6/18/2004 1:47:21 PM]

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The Role of Small Missions in Planetary and Lunar Exploration: Preface Invited presenters briefed COMPLEX on the status of NEAR and Clementine as well as on lessons learned from NASA's Mars Observer and the Small Explorer program. In addition, the committee heard a series of personal views on the Discovery program by representatives from academia and the aerospace industry. The meeting concluded with a tour of the Clementine Control Center ("Batcave") in Alexandria, Virginia. The committee had previously been briefed on Mars Pathfinder during a visit to NASA's Jet Propulsion Laboratory in January 1993. Work on the study continued in April 1994 at NASA's Ames Research Center in Moffett Field, California. COMPLEX heard a series of presentations from the PIs of a selection of candidate Discovery missions, each exhibiting a different managerial relationship between the PI's team, its industrial partner, and the associated NASA center. The committee's goal was not to assess the scientific potential or programmatic risk of any of these particular missions, but rather to focus on management issues. The meeting concluded with a round- table discussion of Discovery-related issues between the committee, PIs, and guests from NASA-Ames, local industry, and academia. As part of the outreach activities for this study, COMPLEX's chair made a public presentation to the space science community at NASA-Ames on the committee's recent studies. The study continued at a summer workshop at the National Research Council's Beckman Center in Irvine, California, in May-June 1994. Part of this meeting was devoted to updates on the status of Mars Surveyor and Clementine, and plans devised by NASA's Outer Planets Science Working Group on small missions to the outer solar system. Work on the report was finished in the spring of 1995 following revisions arising from comments by the Space Studies Board and external reviewers. Joseph A. Burns, Chair Committee on Planetary and Lunar Exploration file:///C|/SSB_old_web/smlpref.html (2 of 3) [6/18/2004 1:47:21 PM]

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The Role of Small Missions in Planetary and Lunar Exploration: Executive Summary The Role of Small Missions in Planetary and Lunar Exploration Executive Summary The last 30 years have seen remarkable progress in our understanding of the solar system and its diverse constituents. But this period has also seen an upheaval in the political and economic circumstances that have been among the prime drivers of planetary and lunar exploration. The motives that led the United States, the former Soviet Union, and, to a lesser extent, various European nations and Japan to explore the solar system during the past three decades were political as well as scientific. Now, with the end of the Cold War, the political motive has virtually disappeared. With such strong roots in the former East-West confrontation, the space program in general and planetary exploration in particular have become vulnerable to changing national priorities. Some observers question the utility of a space program as an instrument of national policy, and others point to the nation's altered economic fortunes and ask if space exploration is a luxury we can no longer afford. REPORT MENU Against this backdrop, the past successes of the planetary exploration NOTICE program are, paradoxically, endangering its future vitality. Telescopic MEMBERSHIP observations combined with the Apollo lunar landings and a string of highly PREFACE successful robotic missions, including Vikings, Magellan, and the Voyagers, have EXECUTIVE SUMMARY given us a first-order understanding of all the planets and major satellites in the CHAPTER 1 solar system from Sun-scorched Mercury to frigid Neptune; even Pluto's gross CHAPTER 2 characteristics are known from ground-based and Earth-orbital measurements. CHAPTER 3 Thus we have finished the preliminary reconnaissance of the major bodies in the CHAPTER 4 solar system and have entered an era of intensive study of the physical CHAPTER 5 phenomena that shape our planetary neighbors. Increased knowledge and APPENDIX comprehension lead us to pose more fundamental questions requiring increasingly sophisticated and expensive investigations to answer. Thus—quite naturally—the small, simple, and inexpensive spacecraft sufficient 20 to 30 years ago to record basic data about the planets have given way to multibillion-dollar robots capable of performing multidisciplinary investigations in the farthest reaches of the solar system. But the increased scale and scope of planetary missions have a cost other than that measured in dollars. With a planetary program composed only of a few large missions, each spaceflight becomes precious. This is especially true file:///C|/SSB_old_web/smlexe.html (1 of 5) [6/18/2004 1:47:36 PM]

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The Role of Small Missions in Planetary and Lunar Exploration: Executive Summary in an environment of declining status and budgets for space exploration, where the failure of any given mission is no longer tolerable. A result is engineering conservatism, with engineers forced to seek the "perfect" design. At the same time, in a program of few spaceflights, scientists—fearing that no other missions will fly soon—will attempt to take the maximum advantage of available opportunities and potential gains from synergistic measurements, something that could, uncharitably, be interpreted as "trying to cram as much aboard as possible." As we have slowly come to understand, deep-space missions are inherently difficult. Thus it is impossible to ever reduce the risk of failure to zero. With a space program built on occasional comprehensive missions, a simple mechanical failure (as with Galileo), or a breakdown with an uncertain cause (as with Mars Observer), or a budgetary problem (as with the Comet Rendezvous/Asteroid Flyby) can prematurely end-or at least seriously degrade-a large fraction of the nation's effort in planetary exploration. The most widely proposed solution to break this vicious cycle is to return to simpler, cheaper missions. With an assured, steady stream of small missions, occasional failures become, if not acceptable, at least tolerable. Since early in the space program, NASA's astrophysics and space physics programs have built and flown a highly effective series of Explorer spacecraft. These low- to moderate-cost missions have transmitted a virtually continuous stream of important scientific data for more than three decades. NASA's earth science program recently instituted a similar series, the Earth Probes, to fill a comparable niche in its activities. Several attempts have been made over the last decade and a half to introduce a comparable line of small planetary missions. For a variety of reasons, these efforts have all failed. Undaunted, NASA recently proposed again to begin such a program, now called Discovery. Two small planetary missions, the Near-Earth Asteroid Rendezvous (NEAR) and Mars Pathfinder, received new starts in the FY 1994 budget as "Discovery" missions, although, as mentioned in the main report, they do not satisfy NASA's present guidelines for this program. Given this situation, the Space Studies Board charged its Committee on Planetary and Lunar Exploration (COMPLEX) to: 1. Examine the degree to which small missions, such as those fitting within the constraints of the Discovery program, can achieve priority objectives in the lunar and planetary sciences; 2. Determine those characteristics, such as level of risk, flight rate, target mix, university involvement, technology development, management structure and procedures, and so on, that could allow a successful program; 3. Assess issues—such as instrument selection, mission operations, data analysis, and data archiving—to ensure the greatest scientific return from a particular mission, given a rapid development schedule and a tightly constrained file:///C|/SSB_old_web/smlexe.html (2 of 5) [6/18/2004 1:47:36 PM]

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The Role of Small Missions in Planetary and Lunar Exploration: Executive Summary budget; and 4. Review past programmatic attempts to establish small planetary science mission lines, including the Planetary Observers and Planetary Explorers, and consider the impact management practices have had on such programs. In the course of its deliberations, COMPLEX found that rather than representing a fall from past glories, the initiation of a series of small missions presents the planetary science community with the opportunity to expand the scope of its activities and to develop the potential and inventiveness of its members in ways not possible within the confines of large, traditional programs. Some researchers may use the opportunities raised by a program of small missions to enhance or augment comprehensive studies of particularly interesting objects such as Mars and Jupiter. Others may employ them to perform reconnaissance of classes of relatively unknown objects such as comets and asteroids, to pursue aspects of intensive study of the terrestrial planets and the Moon, or to investigate planetary phenomena from Earth orbit. The rapid development schedules achievable with small missions should allow the possibility of exploiting targets of opportunity, should permit greater use of current technology, and should enhance the involvement of all sectors of the educational system in space research. COMPLEX also realized, however, that a program of small planetary missions (such as Discovery) was, in and of itself, incapable of meeting all of the prime objectives contained in its report An Integrated Strategy for the Planetary Sciences: 1995-2010.1 As explained in that report, a responsive planetary exploration program demands a mix of mission sizes ranging from comprehensive missions with multiple objectives (such as Galileo and Cassini) to small missions with highly constrained scientific objectives. For a program of small planetary missions to fulfill its promise, COMPLEX believes that it must satisfy certain criteria. These include the following: 1. A continuing budget line should be initiated that is dedicated to a series of small planetary missions that focus on specific, well-defined objectives and are capable of yielding significant scientific results. The chosen missions should address key scientific questions and objectives as outlined in the report An Integrated Strategy for the Planetary Sciences: 1995-2010. 2. This budget line for small planetary missions should be funded at a level that will permit the launch of at least one mission per year, with approximately half of the accepted missions supported at a level close to the currently announced budget cap of $150 million (FY 1992 dollars), not including inflation. 3. Each mission must be selected through open competition from file:///C|/SSB_old_web/smlexe.html (3 of 5) [6/18/2004 1:47:36 PM]

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The Role of Small Missions in Planetary and Lunar Exploration: Executive Summary proposals presented as an integrated package by a principal investigator. This individual should have full authority to decide the appropriate balance among science performance, mission design, and acceptable risk. 4. NASA should not impose on mission design arbitrary constraints such as preselection of launch vehicle, spacecraft bus, payload, or data rate, nor should NASA specify a particular management structure or a specific institution to run mission operations. 5. The budget, schedule, and risk envelope must be identified in the conceptual and definition phase of mission planning. It is essential for NASA to adhere to the agreed-upon funding profile. 6. Past NASA practices must change in order to foster the development of a streamlined approach to management of each complete mission. 7. As soon as they have been calibrated and validated, data and all subsidiary information (e.g., spacecraft ephemerides) needed for their interpretation should be archived expeditiously to ensure their prompt availability to the entire research community. 8. NASA's Planetary Instrument Definition and Development Program should be augmented to produce highly capable science instruments that are appropriate for use in the Discovery program. 9. The option of using elements of the small-mission philosophy for Mars Surveyor and future large missions should be studied. REFERENCE 1. Space Studies Board, National Research Council, An Integrated Strategy for the Planetary Sciences: 1995-2010, National Academy of Sciences, Washington, D.C., 1994. file:///C|/SSB_old_web/smlexe.html (4 of 5) [6/18/2004 1:47:36 PM]