Special Lecture given by Lawrence A. Taylor

at the University of Wisconsin, Madison

	This lecture focuses on the formation of lunar soil, the <1 cm portion of the regolith. In addition, considerations for in-situ resource utilization (ISRU) are addressed (1 of 42 slides)
	Space weathering is largely responsible for the formation of lunar soil.(2 of 42 slides)
	This is a typical Apollo 17 mare soil (field = 1.2 mm). Note the glass spheres, the individual minerals, and the rock fragments.(3 of 42 slides)
	(4 of 42 slides)
	This is our Unhappy Moon – bombarded by particles, large and small, from space. Micrometeorites can be so small that they cannot be seen by the naked eye, but with velocities up to 200,000 km/hr, they possess sufficient energy to crush and even melt the silicate soil fragments.(5 of 42 slides)
	(6 of 42 slides)
	These are impact-produced craters (~5 microns in diameter) on a lunar glass bead from the soil. The rule of thumb is that the size of the projectile is about 1/10th that of the diameter of the crater it produces. Thus, the size of the micrometeorite was about 0.5 microns (1/100th the diameter of a hair on your head).(7 of 42 slides)
	Comminution and agglutination are the major processes involved in the formation of lunar soils. The other two processes are only of local importance. (8 of 42 slides)
	Micrometeorites impact the lunar soil, some with enough energy to melt the silicate minerals. This melt splashes over grains, quenches to glass, and forms agglutinates. Some melt reaches even higher Ts and partially vaporizes, only to condense on the surfaces of other grains. (9 of 42 slides)
	An agglutinite (1mm across), which is an aggregate of small rock and mineral fragments held together by impact glass.(10 of 42 slides)
	This is a graph depicting the evolution of lunar soil from the initial comminution of rocks to the formation of separate mineral grains and agglutinites. The value Is/FeO is used as the measure of “maturity” of lunar soil. (11 of 42 slides)
	Lunar rocks contain traces of native Fe metal, that is Fe in its elemental state. However, the soil contains 10X more of this native Fe, and this is not material from the impacting micrometeorites. (12 of 42 slides)
	Graph of the partial pressure (fugacity) of O2 versus Temperature. All lunar rocks crystallize from silicate magmas at partial pressures below the Fe-Wustite (Fe-FeO) univariant curve (the blue region). Terrestrial rocks form at higher oxygen fugacities, in the yellow region. (13 of 42 slides)
	Back-scatter electron (BSE) image of agglutinitic glass. The native Fe is white. The large Fe sphere is ~0.5 microns across. Notice the myriad of minute Fe0 grains, resembling stars in the Milky Way. (14 of 42 slides)
	Fully 80-90% of the native Fe in agglutinitic glass is <100 Angstroms (<20 nm). This is in the size region of “single-domain Fe” also called “nanophase Fe.” But how does all this native Fe metal form? (15 of 42 slides)
	(16 of 42 slides)
	The ferromagnetic resonance (FMR) signal for the single-domain Fe is “Is”. (17 of 42 slides)
	(18 of 42 slides)
	(19 of 42 slides)
	(20 of 42 slides)
	Solar wind is preferentially retained by ilmenite (FeTiO3) in lunar soil, such that the TiO2 content of the soil is a first approximation for the presence of solar-wind H2 and He. Combining this with Is/FeO, the soil maturity index, permits the effective estimation of the solar-wind abundances in lunar soils, particularly mare types. (21 of 42 slides)
	Is/FeO increases with decreasing grain size. Agglutinitic glass contents also increase with decreasing grain size. (22 of 42 slides)
	(23 of 42 slides)
	Left: Back-scatter electron (BSE) image of lunar soil. The higher the average atomic number of a phase, the brighter is the image. Right: an X-ray map for Fe. Note the thin rim around the plag (plagioclase), which is largely CaAl2Si2O8 with no effective Fe in its structure. This rim is from vapor-deposited native Fe. (24 of 42 slides)
	This is a transmission electron microscopic (TEM) image of a plagioclase grain showing the nature of the nanophase Fe and SiO2 glass on the surface of the plagioclase. This coating was formed by deposition of SiO2 and Fe vapors produced by superheating of impact-generated, silicate melt. (25 of 42 slides)
	(26 of 42 slides)
	(27 of 42 slides)
	(28 of 42 slides)
	In-Situ Resource Utilization (ISRU) on the Moon. (29 of 42 slides)
	(30 of 42 slides)
	(31 of 42 slides)
	With the cost of bringing material from Earth to the lunar surface on the order of ~$10K/lb, water and H2 and O2 are necessities which must be generated at any lunar base. Solar-wind H2 is readily released from the soil with mild heating (600 oC). (32 of 42 slides)
	There is enough H2 in the upper 2 meters of lunar regolith, when combined with oxygen, to form sufficient water for a huge lake. (33 of 42 slides)
	Where to get O2 (lunar liquid oxygen =- LLOX)? Over 40 wt% of the Moon is oxygen, but combined in the silicate and oxide minerals. (34 of 42 slides)
	Taylor & Carrier (1992) performed an evaluation of 20 processes for the production of oxygen on the Moon. One of the best was judged to be “H2 reduction of ilmenite (FeTiO3).” (35 of 42 slides)
	Factors for consideration in process evaluation and design. (36 of 42 slides)
	Reflected-light photomicrograph (1mm wide) of lunar ilmenite (FeTiO3), abundant in the hi-Ti mare soils (e.g., Apollo 11 and 17 sites). (37 of 42 slides)
	Reaction to produce H2O that can be electrolyzed into H2 and O2. (38 of 42 slides)
	Artist’s rendition of a 3-stage, fluidized-bed reactor for the H2 reduction of ilmenite on the Moon. Note that the energy for this would come from large solar cells. (39 of 42 slides)
	The Moon could effectively become a “gas station” in the sky, where rockets could fuel up for further travel onward to Mars and beyond. (40 of 42 slides)
	Exporting LLH and LLOX to low-Earth orbit, possibly to space station, might become feasible. (41 of 42 slides)
	EPA-approved Universal Miner and “friend.” (42 of 42 slides)

References

SELECTED BIBLIOGRAPHY OF ISRU PUBS By Lawrence A. Taylor

• Taylor, L.A., 1987, Rocks and minerals of the Moon: Materials for a lunar base. Symposium ’86, S86-37, 20p.
• Taylor, L.A., 1988, Generation of native Fe in lunar soil. Proc. Space 88, Amer. Soc. Civil Engr., 67-77.
• Taylor, L.A., 1990, Hydrogen, helium, and other solar-wind components in lunar soil: Abundances and predictions. Proc. Space 90, Amer. Soc. Civil Engr., 68-77.
• Oder, R.R., and L.A. Taylor, 1990, Magnetic beneficiation of highland and hi-Ti mare soils: Magnet requirements. Proc. Space 90, Amer. Soc. Civil Engr., 133-142.
• Taylor, L.A., and R.R. Oder, 1990, Magnetic beneficiation of highland and hi-Ti mare soils: Rock, mineral, and glassy components. Proc. Space 90, Amer. Soc. Civil Engr., 143-152.
• Papike, J.J., L.A. Taylor, and S. Simon, 1991, Lunar minerals. In Lunar Sourcebook, Heiken, Vaniman, and French (eds.), Cambridge Univ. Press, Chapter 5, 121-181.
• Taylor, L.A., B. Cooper, D.S. McKay, and R.O. Colson, 1991, Oxygen production on the Moon: Processes for different feedstocks. In Advanced Materials – Applications of Mining and Metallurgical Processing Principles, Publ. of Soc. Min., Metal., and Explor. (SME), 29-45.
• Taylor, L.A., and W.D. Carrier, III, 1992, The feasibility of processes for the production of oxygen on the Moon. In Engineering, Construction, Operations in Space III, Vol. I, Eds. Sadeh, Sture and Miller, ASCE, New York, 752-762.
• Taylor, L.A., and D.S. McKay, 1992, Beneficiation of lunar rocks and regolith: Concepts and difficulties. In Engineering, Construction, Operations in Space III, Vol. I, Eds. Sadeh, Sture and Miller, ASCE, New York, 1058-1069.
• Taylor, L.A., 1992, Planetary science and resource utilization at a lunar outpost: Chemical analytical facility requirements. In A Lunar-Based Chemical Analysis Laboratory, Proceedings of the Ninth College Park Colloquim on Chemical Evolution, Eds. Ronnamperu ma and Gehrke, Hampton, 111-131.
• Taylor, L.A., 1992, Resources for a lunar base: Rocks, minerals, and soil of the moon. In The Second Conference on Lunar Bases and Space Activities of the 21st Century, NASA Publ. 3166, Vol. 2, 361-377.
• Taylor, L.A., and F. Lu, 1992, The formation of ore mineral deposits on the Moon: A feasibility study. In The Second Conference on Lunar Bases and Space Activities of the 21st Century, NASA Publ. 3166, Vol. 2, 379-383.
• Taylor, L.A., 1992, Production of oxygen on the Moon: Which processes are best and why. Amer. Inst. Aero. Astro. Space Programs & Tech. Confer., AIAA, 92-1662, 1-9.
• Taylor, L.A. and W.D. Carrier, III, 1992, Production of oxygen on the Moon: Which processes are best and why. AIAA Journal, Vol. 30, no. 12, 2858-2863.
• Taylor, L.A., and W.D. Carrier, III, 1993, Oxygen production on the moon: An overview and evaluation. Chapter in Resources of Near-Earth Space, Univ. of Ariz. Series, 69-108.
• Chamberlain, P.G., L.A. Taylor, E.R. Podnieks, and R.J. Miller, 1993, A review of possible mining applications in space. Chapter in Resources of Near-Earth Space, Univ. of Ariz. Series, 51-68.
• Chambers, J.G., L.A. Taylor. A. Patchen, and D.S. McKay, 1994, Mineral liberation and beneficiation of lunar high-Ti mare basalt, 71055: Digital-imaging analyses. In Engineering, Construction, Operations in Space IV, Vol.II, ASCE, New York, 878-888.
• Taylor, L.A., 1994, Evidence of helium-3 on the Moon : Model assumptions and abundances, In Engineering, Construction, Operations in Space IV, Vol. II, ASCE, New York, 678-686.
• Chambers, J.G., L.A. Taylor, A. Patchen, and D.S. McKay, 1995, Quantitative mineralogical characterization of lunar high-Ti mare basalts and soils for oxygen production. J. Geophys. Res.-Planets, 100, E7, 14,391-14,401.
• Higgins, S.J., L.A. Taylor, A. Patchen, J. Chambers, and D.S. McKay, 1996, X-ray digital imaging petrography:Technique development for lunar mare soils. Meteoretics & Planet. Sci., 31, 356-361.
• Taylor, L.A. and D.S. Taylor, 1996, Location of a lunar base:A site selection strategy, In Engineering, Construction, Operations in SpaceV, Vol. III, ASCE, New York, 741-755.
• Taylor, L.A., A. Patchen, D.-H. S. Taylor, J.G. Chambers, and D.S. McKay, 1996, X-ray digital imaging and petrography of lunar mare soils:Data input for remote sensing calibrations, Icarus 124, 500-512..
• Taylor, L.A., and D.-H. Taylor, 1997, Considerations for a return to the Moon and Lunar Base site selection workshops. Jour. Aerosp. Engr. 10, 68-79.
• Taylor, L.A., 1997, Resource utilization at a lunar outpost. In A Lunar-Based Analytical Laboratory, Deepak Publ., Hampton, VA, 99-107.
• Taylor, L.A., 1997, Oxygen and water productions on the Moon, In A Lunar-Based Analytical Laboratory, Deepak Publ., Hampton, VA, 56-63.
• Taylor, L.A., and Kulcinski, G.L., 1999, Helium-3 on the Moon for Fusion Energy: The Persian Gulf of the 21st Century. Solar System Research 33, 338-345.
• McKay, D.S., and Taylor, L.A., 1999, Lunar resource utilization. In Lunar Base Handbook, (editor, P. Eckart), McGraw-Hill, 603-606.
• Taylor, L.A., Pieters, C., Keller, L.P., Morris, R.V., McKay, D.S., Patchen, A., and Wentworth, S., 2000, Space weathering of lunar mare soils: New understanding of the effects of reflectance spectroscopy. Space 2000, Amer. Soc. Civil Engr., 703-711.
• Pieters, C.M., Taylor, L.A., Noble, S.K., Keller, L.P., Hapke, B., Morris, R.V., Allen, C.C., McKay, D.S., and Wentworth, S., 2000, Space weathering on airless bodies: Resolving a mystery with lunar samples. Meteor. Planet. Sci. 35, 1101-1107.
• Taylor, L.A., Pieters, C., Keller, L.P., Morris, R.V., McKay, D.S., Patchen, A., and Wentworth, S., 2001, The effects of space weathering on Apollo 17 mare soils: Petrographic and chemical characterization. . Meteor. Planet. Sci. 36, 285-299.
• Noble, S.K., Pieters, C.M., Taylor, L.A., Morris, R.V., Allen, C.C., McKay, D.S., and Keller, L.P., 2001, The optical properties of the finest fraction of lunar soil: Implications for space weathering. . Meteor. Planet. Sci. 36, 31-42.