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MICROGRAVITY RESEARCH IN SUPPORT OF TECHNOLOGIES FOR THE HUMAN EXPLORATION AND DEVELOPMENT OF SPACE AND PLANETARY BODIES Committee on Microgravity Research Space Studies Board Commission on Physical Sciences, Mathematics, and Applications National Research Council NATIONAL ACADEMY PRESS Washington, D.C.
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. Support for this project was provided by Contract NASW 96013 between the National Academy of Sciences and the National Aeronautics and Space Administration. Any opinions, findings, conclusions, or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the sponsor. International Standard Book Number 0-309-06491-0 Cover design by Penny Margolskee. Copies of this report are available from Space Studies Board National Research Council 2101 Constitution Avenue, NW Washington, DC 20418 Copyright 2000 by the National Academy of Sciences. All rights reserved. Printed in the United States of America
National Acaclemy of Sciences National Acaclemy of Engineering Institute of Meclicine National Research Council 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 M. Alberts 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. William A. Wulf is 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. 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 commu- nity 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 Acad- emies and the Institute of Medicine. Dr. Bruce M. Alberts and Dr. William A. Wulf are chairman and vice chairman, respectively, of the National Research Council.
COMMITTEE ON MICROGRAVITY RESEARCH RAYMOND VISKANTA, Purdue University, Chair ROBERT A. ALTENKIRCH, Mississippi State University ROBERT L. ASH, Old Dominion University ROBERT J. BAYUZICK, Vanderbilt University CHARLES W. CARTER, JR., University of North Carolina at Chapel Hill GRETCHEN J. DARLINGTON,* Baylor College of Medicine RICHARD T. LAHEY, JR., Rensselaer Polytechnic Institute RALPH A. LOGAN, AT&T Bell Laboratories (retired) FRANKLIN K. MOORE, Cornell University WILLIAM W. MULLINS, Carnegie Mellon University (emeritus) ROSALIA N. SCRIPA,* University of Alabama at Birmingham FORMAN A. WILLIAMS, University of California at San Diego SANDRA J. GRAHAM, Study Director ANNE K. SIMMONS, Senior Project Assistant CATHY GRUBER, Senior Project Assistant (through May 1998) *Former member. v
SPACE STUDIES BOARD CLAUDE R. CANIZARES, Massachusetts Institute of Technology, Chair MARK R. ABBOTT, Oregon State University FRAN BAGENAL, University of Colorado DANIEL N. BAKER, University of Colorado ROBERT E. CLELAND, University of Washington GERARD W. ELVERUM, JR.,* TRW Space and Technology Group MARILYN L. FOGEL, Carnegie Institution of Washington BILL GREEN, Former Member, U.S. House of Representatives JOHN H. HOPPS, JR., Rozewell, Georgia CHRIS J. JOHANNSEN, Purdue University ANDREW H. KNOLL,* Harvard University RICHARD G. KRON, University of Chicago JONATHAN I. LUNINE, University of Arizona ROBERTA BALSTAD MILLER, Columbia University GARY J.OLSEN, University of Illinois at Urbana-Champaign MARY JANE OSBORN, University of Connecticut Health Center GEORGE A. PAULIKAS, The Aerospace Corporation (retired) JOYCE E. PENNER, University of Michigan THOMAS A. PRINCE, California Institute of Technology PEDRO L. RUSTAN, JR., U.S. Air Force (retired) GEORGE L. SISCOE, Boston University EUGENE B. SKOLNIKOFF, Massachusetts Institute of Technology MITCHELL SOGIN, Marine Biological Laboratory NORMAN E. THAGARD, Florida State University ALAN M. TITLE, Lockheed Martin Advanced Technology Center RAYMOND VISKANTA, Purdue University PETER W. VOORHEES, Northwestern University JOHN A. WOOD, Harvard-Smithsonian Center for Astrophysics JOSEPH K. ALEXANDER, Director *Former member. v!
COMMISSION ON PHYSICAL SCIENCES, MATHEMATICS, AND APPLICATIONS PETER M. BANKS, Veridian ERIM International, Inc., Co-chair W. CARL LINEBERGER, University of Colorado, Co-chair WILLIAM F. BALLHAUS, JR., Lockheed Martin Corporation SHIRLEY CHIANG, University of California at Davis MARSHALL H. COHEN, California Institute of Technology RONALD G. DOUGLAS, Texas A&M University SAMUEL H. FULLER, Analog Devices, Inc. JERRY P. GOLLUB, Haverford College MICHAEL F. GOODCHILD, University of California at Santa Barbara MARTHA P. HAYNES, Cornell University WESLEY T. HUNTRESS, JR., Carnegie Institution of Washington CAROL M. JANTZEN, Westinghouse Savannah River Company PAUL G. KAMINSKI, Technovation, Inc. KENNETH H. KELLER, University of Minnesota JOHN R. KREICK, Sanders, a Lockheed Martin Company (retired) MARSHA I. LESTER, University of Pennsylvania DUSA M. McDUFF, State University of New York at Stony Brook JANET L. NORWOOD, Former Commissioner, U.S. Bureau of Labor Statistics M. ELISABETH PATE-CORNELL, Stanford University NICHOLAS P. SAMIOS, Brookhaven National Laboratory ROBERT J. SPINRAD, Xerox PARC (retired) MYRON F. UMAN, Acting Executive Director (as of August 1999) NORMAN METZGER, Executive Director (through July 1999) . . via
Preface The study that is the subject of this report was initiated in early 1996 by a request to the Committee on Microgravity Research (CMGR) from the leadership of NASA's Microgravity Science and Applications Divi- sion1 to perform an assessment of scientific and related technological issues facing NASA' s Human Exploration and Development of Space (HEDS) endeavor. The committee agreed to consider mission enabling and enhancing technologies that, for development, would require an improved understanding of fluid and material behavior in a reduced-gravity environment. The committee would then identify opportunities for Microgravity research to contribute to the understanding of fundamental scientific questions underlying exploration technologies and make recommendations for some areas of directed research. The study was to be carried out in two phases. The phase I report, An Initial Review of Microgravity Research in Support of Human Exploration and Development of Space, was published in 1997 (National Academy Press, Washington, D.C.~. That first report represented a preliminary look at broad categories of HEDS technologies and contained primarily programmatic recommenda- tions. For the second phase of the study, the committee undertook a more in-depth examination of a wide range of specific technologies that might be applicable to human exploration. As no single office at NASA had assembled a list of critical technologies needed for HEDS, the committee has included the results of its own technology survey in this report. This survey was carried out by canvassing the available literature, participating in relevant workshops, and receiving extensive briefings from experts in NASA, industry, and academia. The goal of this phase II report was to provide specific recommendations for areas of research on fundamental phenomena. The phenomena recommended for study would be those that had the potential to significantly affect the operation of future exploration technologies and that needed to be better understood to enable the optimization or eventual development of those technologies. Since the time frame for technology development from fundamental research is generally quite long, the committee chose to focus, in this phase II report, primarily on those technology areas that might be important for space exploration one to three decades into the future. In its study, the committee utilized a large number of past reports from various sources. Among the previous National Research Council reports relevant to this study, the committee took particular note of the following: Now the Microgravity Research Division (MRD). Six
x PREFACE · Microgravity Research Opportunities for the 1990s, Space Studies Board, National Research Council (National Academy Press, Washington, D.C., 1995), reviewed the various research topics currently studied within the different scientific disciplines of NASA' s microgravity research program and suggested research and program- matic priorities and recommendations. The report focused on fundamental research that could contribute to basic advances within individual disciplines. · Space Technology for the New Century, Aeronautics and Space Engineering Board, National Research Council (National Academy Press, Washington, D.C., 1998), examined space technology needs in the post-2000 time frame and identified a few high-risk, high-payoff areas where research investments might benefit a range of future missions. · Advanced Technology for Human Support in Space, Aeronautics and Space Engineering Board, National Research Council (National Academy Press, Washington, D.C., 1997), reviewed the NASA programs that support development of technologies for human life support and recommended improved strategies for managing the development process. · Space Technology to Meet Future Needs, Aeronautics and Space Engineering Board, National Research Council (National Academy Press, Washington, D.C., 1987), evaluated national advanced space technology requirements and recommended a long-term technology program focus for NASA.
Acknowledgment of Reviewers This report has been reviewed by individuals chosen for their diverse perspectives and technical expertise, in accordance with procedures approved by the National Research Council's (NRC's) Report Review Committee. The purpose of this independent review is to provide candid and critical comments that will assist the authors and the NRC in making the published report as sound as possible and to ensure that the report meets institutional standards for objectivity, evidence, and responsiveness to the study charge. The contents of the review comments and draft manuscript remain confidential to protect the integrity of the deliberative process. We wish to thank the following individuals for their participation in the review of this report: Rino Buonamici, Westinghouse Hanford Company (retired), Daniel C. Drucker, University of Florida (emeritus), Jerry P. Gollub, Haverford College, Lionel Isenberg, Jet Propulsion Laboratory (retired), Joseph Miller, TRW Space and Electronics Group (retired), Simon Ostrach, Case Western Reserve University, Julio M. Ottino, Northwestern University, Frederick G. Pohland, University of Pittsburgh, William C. Reynolds, Stanford University, and William A. Sirignano, University of California at Irvine. Although the individuals listed above have provided many constructive comments and suggestions, responsi- bility for the final content of this report rests solely with the authoring committee and the NRC. x~
Contents EXECUTIVE SUMMARY I INTRODUCTION Objectives, 9 The Exploration Environment, 10 Radiation in Space, 10 Planetary Bodies, 10 Report Organization and Development, 13 References, 14 II BRIEF DESCRIPTIONS OF PHENOMENA IMPORTANT IN REDUCED GRAVITY Reference, 19 III SURVEY OF TECHNOLOGIES FOR THE HUMAN EXPLORATION AND DEVELOPMENT OF SPACE III.A Power Generation and Storage, 21 Introduction, 21 Power Generation Systems, 23 Solar Power Systems, 23 Chemical Power Systems, 24 Nuclear Power Systems, 26 Energy Storage, 26 Some Selected Subsystem Technologies, 28 Boiler for the Rankine Cycle, 29 Radiators, 29 Proton-Exchange Membrane Fuel Cells, 30 Capillary-Driven, Two-Phase Devices, 31 Vapor-Pressure Pumped Loops, 33 Alkali Metal Thermal-to-Electric Conversion, 33 Summary of the Impact of Reduced Gravity on Selected Subsystems, 34 References, 35 . . . Xti! 9 17 21
xlv CONTENTS III.B Space Propulsion, 36 Introduction, 36 Required Space Propulsion Capabilities, 36 Space Propulsion Systems, 37 Chemical Rocket, 37 Nuclear Thermal Rocket, 39 Nuclear Electric Propulsion, 41 Solar Thermal, 43 Solar Sail, 43 Laser Thermal, 43 Laser Sail, 43 Tether, 43 Atmospheric Drag Aeroassist, 44 Major Subsystems, Their Purposes, and Their Sensitivities to Reduced Gravity, 44 Nuclear Fission Reactor, 44 Cryogenic Storage System, 44 Radiator System, 45 Solar Collector, 45 Boiler for a Rankine Cycle, 45 Gas or Vapor Turbines, 45 Liquid Pumps, 46 Compressor, 46 Condenser for a Rankine Cycle, 46 Vaporizer for Propellant, 46 Switch Gear and Electric Power Conditioning, 46 Common Design Elements, 47 General Concerns Regarding Propulsion and Power in Reduced Gravity, 48 Variable Gravity, 48 Transient Operation and Unsteady Processes, 49 Multiphase Flow, 49 Need for Artificial Gravity, 50 Reliability, 50 Nuclear System Development, 50 Summary of the Effect of Reduced Gravity on Selected Subsystems, 50 References, 51 III.C Life Support, 52 Introduction, 52 Atmospheric Homeostasis, 53 Air Revitalization, 53 Carbon Dioxide Removal and Concentration, 54; Reduction of Carbon Dioxide, 55; Oxygen Generation Water Electrolysis, 55; Oxygen Supply and Regeneration, 55 Temperature and Humidity Control, 55 Trace Biological, Chemical, and Particulate Contaminant Control, 56 Water Homeostasis, 56 Recovery, 56 Solid Waste Management, 57 Food Production, 58 Summary of the Impact of Reduced Gravity on Selected Subsystems, 59 References, 60
CONTENTS XV III.D Hazard Control, 60 Introduction, 60 Fire Protection, 61 Electrical System Fault Diagnostic and Response System, 61 Smoke Detectors, 61 Fire Extinguishers, 61 Postfire Cleanup, 62 Spill Cleanup, 62 Radiation Shielding, 62 Passive Bulk Shielding, 63 Electromagnetic Shielding, 63 Electrostatic Shielding, 64 Chemical Radioprotection, 64 Protection from Chemical and Biological Contamination, 64 Summary of the Effect of Reduced Gravity on Hazard Protection Systems, 65 References, 65 III.E Materials Production and Storage, 66 Introduction, 66 Mining, 68 Volatilization/Condensation, 68 Lunar Volatiles, 69 Extraction of Water Ice on Low-Gravity Surfaces, 70 Material Handling and Transport, 70 Concentration and Beneficiation of Feedstock, 71 Electrostatic and Magnetic Beneficiation, 71 Atmosphere Acquisition (and Compression) Systems, 72 Filtration, 72 Fluid-Based Chemical Processing, 76 Electrochemical Processing, 76 Water Electrolysis, 76; Gas Phase Electrochemical Extraction, 78; Solid Electrolyte Electrolysis: Extraction of Oxygen from Carbon Dioxide, 79 Molten Metal Electrolysis, 80 Lunar Magma Electrolysis, 80; Production of Aluminum from Orbital Debris, 80 Radio-Frequency Processing of Materials, 80 RF Processing of the Martian Atmosphere, 81; Separation or Filtration of Solid Particles (Dust) from RF-Processed Gas Streams, 81 Oxygen Production, 82 Sabatier Reactors, 82; Reverse Water Gas Shift, 83; Ilmenite Reduction as a Source of Oxygen, 84; Pyrolysis, 85 Cryogenic Storage, 86 Summary of the Effect of Reduced Gravity on Selected Subsystems, 87 Additional Processes of Interest, 88 Ejecta Capture from Asteroids and Comets, 88 Mining Helium-3, 90 References, 91 III.F Construction and Maintenance, 94 Introduction, 94 Site Preparation, 95 Construction, 96
xv! Concreting, 97 Production of Portland Cement, 97 Aggregates, 98 Batching, Mixing, and Placement, 98 Hydration of Cement and Curing, 98 Summary of Gravity Impacts, 99 Direct Manufacturing, 99 Fabrication of Components and Structural Elements from Raw or Processed Materials, 100 Casting in Reduced Gravity, 101 Sintering, 102 Composite Materials, 103 Joining Methods in Space, 103 References, 104 III.G Matrices of Subsystems, Processes, and Phenomena, 106 IV PHENOMENA OF IMPORTANCE IN REDUCED GRAVITY IV.A General Considerations, 111 Introduction, 111 Gravity and Density Difference, 112 Gravity-Density Coupling in Various Basic Processes, 112 Gravity Regime Boundaries, 113 Research Issues, 114 References, 114 IV.B Interfacial Phenomena, 114 Capillary Equilibrium and Dynamic Forms, 114 Research Issues, 115 Wetting, 115 Research Issues, 117 Marangoni Effect, 117 Research Issues, 119 References, 119 IV.C Multiphase Flow, 120 Phase Separation and Distribution, 121 Other Multiphase Phenomena, 125 Research Issues, 128 Mixing, 128 Research Issues, 129 Multiphase Systems Dynamics, 129 Excursive Instabilities, 130 Pressure-Drop Instabilities, 130 Density-Wave Oscillations, 130 Research Issues, 132 Flow in Porous Media, 134 Research Issues, 135 References, 135 IV.D Heat Transfer, 137 Introduction, 137 Single-Phase Convection, 139 Research Issues, 140 Evaporation Heat Transfer, 140 CONTENTS 111
CONTENTS Research Issues, 142 Boiling Heat Transfer, 142 Pool Boiling, 142 Research Issues for Pool Boiling, 145 Flow Boiling, 145 Research Issues for Flow Boiling, 146 Condensation Heat Transfer, 146 Research Issues, 147 Two-Phase Forced Convection Heat Transfer, 147 Research Issues, 148 Solid/Liquid Phase-Change Heat Transfer, 149 Research Issues, 149 Phase-Change Heat Transfer in Porous Media, 150 Research Issues, 151 References, 151 IV.E Solidification, 153 Research Issues, 155 References, 155 IV.F Chemical Transformation, 156 Combustion, 156 Behavior of Combustion Phenomena in Microgravity, 156 Mixture Flammability, 157 Flame Instabilities, 158 Gas Diffusion Flames, 158 Droplet Combustion, 158 Cloud Combustion, 158 Smoldering, 158 Flame Spread, 158 Implications of the Behavior of Combustion Phenomena in Microgravity for Spacecraft Design and Operations, 159 Affected Technologies, 160 Research Issues, 160 Pyrolysis, 160 Research Issues, 161 Solution Chemistry, 161 References, 161 IV.G Behavior of Granular Materials, 162 Lunar and Martian Regolith, 162 Research Issues, 163 Kinetics of Granular Flow, 164 Research Issues, 165 References, 165 V OTHER CONCERNS V.A Indirect Effects of Reduced Gravity on Design, 167 Piping Systems, 167 Bearings, 168 Seals, 168 Robots and Articulated Structures, 169 Tanks and Antennas, 169 xvii 167
. . . xvit! Summary of Concerns Prompted by Considering the Indirect Effects of Reduced Gravity, 170 References, 170 V.B Microgravity Countermeasures, 170 Spacecraft Rotation, 171 Liquid/Vapor Separators, 173 Rotary Fluid Management Device, 173 Free Vortex Separator, 174 Oscillation as a Microgravity Countermeasure, 174 Flow Deflection as a Microgravity Countermeasure, 175 Research on Countermeasures, 175 References, 176 V.C Predictive Models, Reliability, and Probabilistic Risk Assessment, 177 References, 177 VI SUMMARY OF RECOMMENDED RESEARCH ON FUNDAMENTAL PHENOMENA Basis for Recommendations, 179 Recommended Research, 180 Surface or Interfacial Phenomena, 180 Multiphase Flow and Heat Transfer, 180 Multiphase System Dynamics, 181 Fire Phenomena, 182 Granular Materials, 182 Solidification and Melting, 183 Other Concerns, 183 Reduced-Gravity Countermeasures, 183 Indirect Effects of Reduced Gravity, 184 VII PROGRAMMATIC RECOMMENDATIONS A Research Approach for the Development of Multiphase Flow and Heat Transfer Technology, 186 Coordination of Research and Design, 186 Microgravity Research and the International Space Station, 188 Peer Review for Reduced-Gravity Research, 188 References, 188 APPENDIXES A STATEMENT OF TASK B SYMBOLS C GLOSSARY D ACRONYMS E BIOGRAPHIES OF COMMITTEE MEMBERS CONTENTS 179 185 191 193 195 199 203