Resources of Near-Earth Space
|Resources of Near-Earth Space, edited by John S. Lewis, Mildred Shapley Matthews, and Mary L. Guerrieri. © 1993 The Arizona Board of Regents. No part of this on-line book may be reproduced in any manner whatsoever without the written permission of the University of Arizona Press.
The National Space Society is proud to present this landmark book in cooperation with the University of Arizona Press. NSS supplied the volunteer labor to scan the book and create the PDF files which reside on the University of Arizona Press website. The Introduction and abstracts are available here in searchable text format, along with links to the complete PDF files for each chapter. Each chaper PDF is 1-3 megabytes in size.
LARRY A. HASKIN and RUSSELL 0. COLSON,
Washington University, St. Louis
ABSTRACT: From studies of lunar samples we know that extensive chemical fractionation occurred during the Moon's igneous differentiation, and from remote sensing studies we know that the Moon's outer crust is laterally and vertically heterogeneous on large and small scales. Here, we review current knowledge of chemical compositions of lunar materials in the context of known or suspected lunar geochemical processes. We speculate on how various elements might have been concentrated into potential ore deposits.
PETER G. CHAMBERLAIN,
U. S. Bureau of Mines, Washington Office
ABSTRACT: Successful exploration of Mars and outer space may require base stations strategically located on the Moon. Such bases must develop a certain self-sufficiency, particularly in the critical life support materials, fuel components, and construction materials. This chapter reviews technology for the first steps in lunar resource recovery—those of mining. The topic is covered in three main categories: engineering properties of lunar regolith, surface mining and excavation, and underground mining. The chapter also contains a brief discussion of in-situ processes. The text describes mining technology ranging from simple digging and hauling vehicles (the "strawman") to more specialized technology including underground methods. In-situ processes—chemical and thermal—are identified to stimulate further thinking by future researchers.
LAWRENCE A. TAYLOR, University of Tennessee
ABSTRACT: The production of oxygen on the Moon utilizing indigenous resources and materials is paramount to a successful permanent habitation on the lunar surface. At least 20 different processes have been put forth to accomplish this. The two lunar liquid oxygen generation schemes which have received the most study to date are those involving: (1) reduction of ilmenite (FeTiO3) with H2, but also by CO and CH4; and (2) molten silicate (magma) electrolysis, both direct and fluoride-fluxed. Several other processes, including glass reduction with H2, vapor phase pyrolysis, ion (plasma) pyrolysis, carbochlorination, HF acid leaching, and fluorine extraction, also have received significant study. However, all processes should be addressed at this stage in our considerations. There is an obvious need for considerably more experimentation and study. Some of these requisite studies are in progress. This chapter reviews 20 processes for the production of oxygen on the Moon, including an evaluation of the perceived feasibility for each.
RUSSELL O. COLSON and LARRY A. HASKIN, Washington University
ABSTRACT: Because of the Earth's substantial gravity well, the Moon, with its lower gravity, is a potentially valuable source of materials for use in space. Oxygen, fuel for both humans and rockets, is the most abundant element on the Moon and a potentially valuable lunar resource if it can be easily extracted from the rocks in which it is chemically bound. The unique conditions on the Moon, such as vacuum, absence of many reagents common on the Earth, and presence of very nontraditional "ores" suggest that a unique and nontraditional process for extracting materials from these ores may prove the most practical. This process should be simple, problem-free and energy efficient. Electrolysis of molten silicate has the advantages of simplicity of concept, absence of need to supply reagents from Earth, and low-power and mass requirements for the processing plant, thus meeting the criteria above. Electrolysis experiments using 1 to 2 g quantities of silicate melt have been done at low cell voltages and indicate that the process can be very energy efficient. Materials for container and electrodes have been identified that are stable under electrolysis conditions for at least 2 hr. Larger experiments of longer duration are needed to further test the durability of container and electrode materials. Silicate melt electrolysis is versatile with respect to feedstock composition, meaning that almost any lunar material can be used as feedstock. In addition, the process is not sensitive to expected variations in feedstock composition, meaning that compositional variations over a limited area, such as might be mined for feedstock, do not require compensating adjustments to the process. Developing a process to extract oxygen from lunar materials is an important step in learning to live in space. As such, its value to humanity may be much greater than indicated by a calculation of the cost versus return.
WOLFGANG SEBOLDT and STEPHAN LINGNER, German Aerospace Research Establishment
ABSTRACT: Lunar soil and rocks are substantial resources for oxygen which could probably be exploited during future lunar activities. For the liberation of this oxygen, the use of fluorine gas as a strong reagent is discussed. Fluorine is capable of decomposing a variety of silicates. Results of fluorination experiments support the idea that nearly complete separation of elemental oxygen from lunar soil components at relatively moderate temperatures can be expected. Two processing concepts are outlined. They differ in several aspects, especially with regard to beneficiation needs and recycling strategies. Recycling of fluorine should be achieved to a high degree to make the process economically promising. Reduction of reaction by-products for fluorine recycling is proposed to be carried out by either sodium or atomic hydrogen, producing also useful metals and other materials. For both concepts fluorine recovery (final electrolysis of resulting NaF or HF) seems to be the most energy-demanding step. Handling of fluorine and its compounds should pose no major problems, inasmuch as several container materials are known which effectively resist corrosion.
Y. ZHAO and F. SHADMAN, University of Arizona
ABSTRACT: The kinetics and mechanism of reduction of ilmenite by carbon monoxide as well as hydrogen at 800 to 1100°C were investigated. The temporal profiles of conversion have a sigmoidal shape and indicate the presence of three different stages (induction, acceleration and deceleration) during CO reduction at all temperatures and 1-12 reduction at the temperatures below 876°C. The apparent activation energies based on the initial rates are 29.6 kcal/mole for CO reduction and 22.3 kcal/mole for H2 reduction, respectively. The reaction is first order with respect to carbon monoxide and hydrogen under the experimental conditions studied. Both SEM and EDX analyses show that the diffusion of Fe product away from the reaction front and through the TiO2 phase, followed by the nucleation and growth of a separate Fe phase are important steps in both reduction processes. The main difference between these two reactions is that TiO2 can be reduced to lower oxides of titanium by hydrogen at temperatures higher than 876°C, and the reduction rate of ilmenite by H2 is much faster than that of ilmenite by CO. A novel process flow sheet for carbothermal reduction process is also presented.
CONSTANCE L. SENIOR, PSI Technology Company
ABSTRACT: Production of oxygen has been identified as a high priority for lunar manufacturing with the primary use for oxygen as a propellant. The economic incentive for oxygen production from lunar material is the savings in transportation costs of oxygen from the Moon as compared to oxygen brought up from Earth. Pyrolysis or vapor-phase reduction involves heating material to temperatures sufficient to allow partial decomposition of metal oxides and vaporization. Some metal oxides give up oxygen upon heating, either in the gas phase to form reduced gaseous species or in the condensed phase to form a metallic phase. Pressures in the range of 0.01 to 0.1 torr are predicted for the pyrolysis step with melt temperatures of 2000 to 2200 K. Metal-containing species in the gas phase can be collected by condensation and thus separated from oxygen. The simplicity and the ability to use unbeneficiated regolith for feedstock make it attractive for lunar manufacturing. This chapter discusses current experimental and theoretical work as well as the process conditions and requirements for feedstock, power, and equipment. Suggestions for future work needed to bring the pyrolysis process to technical maturity are also discussed.
BRENT SHERWOOD and GORDON R. WOODCOCK, Boeing Defense and Space Group
ABSTRACT: The practicality of producing oxygen from indigenous lunar resources is addressed from three facets: technical, economic, and evolutionary. Technical complications of integrating oxygen production into the function of a lunar base are summarized, based on generalizing conclusions from the comprehensive point-design and analysis of one early, oxygen-producing lunar base concept. Economic viability is assessed using three methods: parametric equations, return-on-investment analysis, and input-output modeling. Requirements for technology advancement and the marginal economic return resulting from these analyses are evaluated in the light of long-term expansion of lunar capabilities. The development of lunar oxygen production is found to appear feasible and guardedly advisable, albeit only as a government-funded venture.
E. REPIC, R. WALDRON, W. McCLURE and H. WOO, Rockwell International Corporation
ABSTRACT: This chapter discusses the mission and transportation applications of in-situ-derived propellants derived from lunar materials. First, a brief summary of available materials and associated propellants is presented. Details of the processing of lunar propellants has been given in earlier chapters. Next, some typical lunar transportation vehicle concepts are discussed to show the types of chemically fueled designs being considered today and the benefits of using in-situ-derived propellants. Finally, time-phased mission applications are presented and some mass and cost trades discussed. The results clearly show that the benefits obtainable from the use of in-situ-derived propellants for lunar and Mars operations are considerable if Earth to orbit launch costs stay as high as they are now. If a factor of 10 reduction in these launch costs is forthcoming (the goal of the Advanced Launch System and its successors), then the benefits of using lunar propellants becomes minimal.
R. D. WALDRON, Rockwell International
ABSTRACT: Potentially useful nonvolatile products can be produced from raw lunar rocks and soils or mass fractions thereof obtained by one or more physical or chemical processing operations. The feasibility and practicality of lunar manufacture of specific components or systems will be constrained by available materials properties, and complexity and capital requirements of processing and manufacturing facilities. Classifications of input materials and preprocessing and refining systems are presented and the differences in materials specifications required for surface and flight or export hardware applications are discussed. Rationale for selection(s) of refining processes are outlined. Generic descriptions of manufacturing operations applicable to metallic and nonmetallic hardware are reviewed. Specific examples of available candidate materials and applicability to provide structural, thermal, chemical, electromagnetic and optical properties needed for various applications classes are presented.
CHANDRA S. DESAI, HAMID SAADATMANESH and KIRSTEN GIRDNER, University of Arizona
ABSTRACT: Development of structural materials from locally derived space materials and study of their mechanical properties for construction and other uses are important toward establishment of outputs and habitats on the moon and other planets. This chapter provides a brief review of various methods such as sintering and casting for the manufacture of construction materials from lunar simulants. Then two alternative and new methods developed are described. They involve (1) thermal liquefaction in which the mixture of a lunar simulant and various metallic fibers is liquified at a temperature of about 1100°C so as to form a matrix of everlapping zones of melted simulants and fibers, and (2) compaction of dry simulants under different vacuum levels using a newly developed vacuum triaxial device. The stress-strain-strength properties of the resulting materials are determined by using beam bending, uniaxial compression and triaxial compression tests. It is found that the thermal liquefaction leads to materials with significantly enhanced flexural and ductility properties compared to the sintered materials that are found to be brittle. The future research will involve such factors as use of glass fibers, techniques for optimization of mechanical properties and additional testing for tensile, fracture, and multiaxial properties of the resulting materials. It is believed that such materials may be produced on the moon by using solar energy without the use of water, and can lead to applications not only for construction, but also for machines and other structures for use in the colonization of space.
B. J. PLETKA, Michigan Technological University
ABSTRACT: The development of an infrastructure for a manned lunar base requires the fabrication of components such as launch and landing pads, foundations, unpressurized structures and possibly roads. The fabrication of these structural elements using the lunar regolith is explored in this chapter. Methods appropriate for producing blocks or slabs of lunar basalt were selected based on the characteristics of the lunar regolith and the lunar surface conditions. Liquid-phase sintering appears to be the most promising technique for producing large structural components, and the key processing issues which have to be addressed in order to construct a regolith sintering facility are discussed. Melting and solidification of lunar basalt to yield glassy structures are also examined as the anhydrous lunar environment may lead to significant improvements in the mechanical properties of glasses; data in support of this hypothesis are presented.
W. HOWARD POISL and BRIAN D. FABES, University of Arizona
ABSTRACT: Any lunar outpost will generate a strong demand for refractory materials. We have studied the feasibility of using lunar resources to produce two classes of refractories— refractory bricks and aerobrake heat shields—representing two extremes of compositional and processing complexity. We conclude that refractory bricks for low temperature applications can be produced on the Moon, though not every step of the process is clear, e.g., the amount, type and source of binders. More advanced refractory materials, such as aerobrake heat shields, will initially have to be transported from Earth. However, as the lunar outpost grows and novel processing techniques are developed, even complicated, high temperature refractory structures could be produced on the Moon.
BRUCE FEGLEY, JR., Washington University
ABSTRACT: We critically review from a resources perspective the available data on the abundances of the noble gases, hydrogen, carbon, nitrogen, sulfur, fluorine and chlorine in lunar samples. The analytical and mineralogical data relevant to the water content of lunar materials are also reviewed. The factors affecting the abundances of the solar-windimplanted volatiles are discussed. The extensive analytical data on the Apollo and Luna samples are used to estimate average global inventories of these volatiles in the lunar regolith. The analytical data are also used to discuss some implications of different volatile extraction schemes such as heating and grain size sorting. The chemistry of lunar volcanic gases is discussed with an emphasis on using the chlorofluorocarbon gases as chemical probes of the water abundance in the lunar interior and on the transport of ore-forming metals. Finally, we highlight some of the major unanswered questions about using lunar volatiles as resources and make recommendations for future resource related work on lunar volatiles.
ROBERT L. STAEHLE, JAMES D. BURKE and GERALD C. SNYDER, Jet Propulsion Laboratory
There are widely dispersed lunar sites of interest for known and potential resources, selenology and observatories. Discriminating characteristics include certain geologic and topographic features, local mineralogy and petrology, solar illumination, view of Earth and the celestial sphere, and soil engineering properties. Space vehicle arrival and departure trajectories favor equatorial and polar sites. Over time, base sites will be developed serving different purposes. Information may be the initial lunar "resource," in the form of observational and in-situ research. Resource-driven sites may see the fastest growth during early decades of lunar development, but selection of initial sites is likely to be driven by suitability for a combination of activities. Only equatorial locations offer nearly all-sky views for astronomy, while most of the far side offers radio isolation. A base in Mare Smythii with subsidiary outposts is favorable for a variety of purposes, and preserves broad resource flexibility. Discovery of accessible volatiles, in the form of polar permafrost, subsurface gas reservoirs, or comet impact remnants, would dramatically increase the attractiveness of such a site from a logistical support and selenological point of view. Amid much speculation, no reliable evidence of such volatiles exists. With the availability of near-constant sunlight for power generation, and permanently shadowed areas at cryogenic temperatures, polar sites require substantially less Earth-launched mass and lower equipment complexity for an initial base. Polar sites are scientifically less interesting. Reliable evidence exists for areas of certain mineral concentrations, such as ilmenite, which could form a feedstock for some proposed resource extraction schemes. In addition to being a source for oxygen and iron, ilmenite harbors higher concentrations of solar-windimplanted H, C, N and He. New data from a lunar polar orbiter are essential for the most informed site selection. Data from the first Galileo flyby have already revealed previously unknown features and will aid surface mineralogical characterization.