Thermophysical properties of Apollo 12 fines

The vacuum thermal conductivity of the Apollo 12 fines is presented as a function of temperature for densities of 1300, 1640 and 1970kg/m³. It is found to vary from about 10^?3W/m-°K at 100°K to about 3 x 10^?3W/m-°K at 400°K. The conductivity of the fines is found to be close to that of terrestrial basalt both under vacuum and at higher pressures. The thermal diffusivity is calculated from conductivity and specific heat data. Average values of the thermal conductivity, thermal diffusivity and thermal parameter are also presented.     

Ferromagnetic and paramagnetic resonance spectra of lunar material: Apollo 12

Electron magnetic resonance spectra of specimens of two crystalline rocks (12021-55 and 12075-19) and of four specimens of fines < 1 mm (12001-16, 12030-16, 12033-50 and 12070-125) have been obtained as a function of spectrometer frequency (9 and 35 GHz), temperature (78 to 300K), heat treatments (to 960°C), and mineral phases (plagioclase, olivine, pyroxferroite, glass, and basaltic fragments). Three paramagnetic ions, Fe³⁺, Ti³⁺ and Mn²⁺, are identified on the basis of spectral characteristics in plagioclase fractions, with concentrations 10¹⁹ ions g^–1. Spectral components of at least two phases with exchange coupling of unpaired spins are resolved in whole rock samples of the crystalline rock specimens. These disappear upon heat treatment in air at 250°C and are presumably the result of an oxidation of the phases. It is suggested that these are non-stochiometric iron-rich oxide phases which approach stochiometry with heating in air. Some of the spectral properties of the characteristic resonance in fines are shown to be inconsistent with the hypothesis that the resonance is due to spherical iron particles. Another intense spectral component observed in samples of 12033-50 (H ~ 3000 Oe,g ~ 4 at 9 GHz andH ~ 3000 Oe,g ~ 2.2 at 35 GHz) is also observed in basaltic appearing fragments selected from 12001-16. It is estimated that the source of this component has concentrations in 12001-16, 12030-16, and 12075-125 that are < 2% the concentration in 12033-50. A similarity of this component to one observed in a crystalline rock sample from 12021-55 heat-treated in air and then left in air for 27 days and to one observed in a sample of fines heat treated at low pressure (< 10^–3 mm Hg) to 800°C is the basis for suggesting that it is also due to a ferromagnetic oxide phase. The spectrum of a ferromagnetic metal platlet from 12001-16, in which the resonance and antiresonance were well resolved, was used to calculate the saturation magnetization and gave a value in reasonable agreement with that of iron as expected.Deceased.American University in Cairo, Cairo, EgyptResearch sponsored by the U.S. Atomic Energy Commission and supported by NASA Contract MSC-T-76458.     

Production of lunar fragmental material by meteoroid impact

The rate of production of new fragmental lunar surface material is derived theoretically on the hypothesis that such material is excavated from a bedrock layer by meteoroid impacts. An overlaying regolith effectively shields the bedrock layer from small impacts, reducing the production rate of centimeter-sized and smaller blocks by a large factor. Logarithmic production rate curves for centimeter to meter-sized blocks are nonlinear for any regolith from centimeters to tens of meters in thickness, with small blocks relatively much less frequent for thicker (older) regoliths, suggesting the possibility of a statistical reverse bedding. Modest variations in the exponents of scaling laws for crater depth-diameter ratio and maximum block-diameter to crater diameter ratio are shown to have significant effects on the production rates. The production rate increases slowly with increasing size of the largest crater affecting the region.     

The potential for metal contamination during Apollo lunar sample curation

Curation and preparation of samples for chemical analysis can occasionally lead to significant contamination. This issue is of concern in the study of lunar samples, especially those from the Apollo sample collection, where available masses are finite. Here we present compositional data for stainless steels that have commonly been used in the processing of Apollo lunar samples at NASA Johnson Space Center, including a chisel and a vessel typically used to transfer Apollo samples to principal investigators. The Type 304 stainless steels are Cr-rich, with high concentrations of Mn (4000–18,000 μg g⁻¹), Cu (1000–22,900 μg g⁻¹), Mo (1030–1120 μg g⁻¹), and W (72–193 μg g⁻¹). They have elevated highly siderophile element (HSE) concentrations (up to 92 ng g⁻¹ Os), ¹⁸⁷Os/¹⁸⁸Os ranging from 0.1310 to 0.1336, and negligible lithophile element abundances. We find that, while metal contamination is possible, significant (≫0.01% by mass) addition of stainless steel is required to strongly affect the composition of the HSE, W, Mo, Cr, or Cu for most Apollo lunar samples. Nonetheless, careful appraisal on a case-by-case basis should take place to ensure contamination introduced through sample processing during curation is at acceptably low levels. A survey of lunar mare basalts and crustal rocks indicates that metal contamination plays a negligible role in the compositional variability of the HSE and W compositions preserved in these samples. Further work to constrain contamination for other properties of Apollo samples is required (e.g., organics, microbes, water, noble gases, and magnetics), but the effect of metal contamination can be well-constrained for the Apollo lunar collection.     

Selenography and selenodesy with Apollo whole-disk lunar photographs I. Selenography

The Apollo whole-disk lunar photographs, with spacecraft lunar nadirs about 70° from the center of mean face, have considerable selenodetic potential provided that the requirements of resolution and precision can be met. Uncertainties in the internal camera geometry degrade the precision and make selenodetic applications doubtful, but selenographic work based on the assumption of a rigorously spherical moon makes lesser demands on the data and is still possible with useful accuracy. The selenographic method is fully developed here and applied to photographs 2505 and 2506 of Apollo 8 to produce a catalog of 635 positions. Of these 206 are farside and extend to 130° East Longitude. A new type of 5-character position word, appropriate for the entire lunar sphere, is used to define sequence in the catalog.     

Comparison of the analytical results from the surveyor,Apollo, and Luna missions

The principal chemical element composition and inferred mineralogy of the powdered lunar surface material at seven mare and one terra sites on the Moon are compared. The mare compositions are all similar to one another and comparable to those of terrestrial ocean ridge basalts except in having higher titanium and much lower sodium contents than the latter. These analyses suggest that most, if not all, lunar maria have this chemical composition and are derived from rocks with an average density of 3.19 g cm^–3. Mare Tranquillitatis differs from the other maria in having twice the titanium content of the others.The chemical composition of the single highland site studied (Surveyor 7) is distinctly different from that of any of the maria in having much lower amounts of titanium and iron and larger amounts of aluminium and calcium. Confirmation of these general characteristics of lunar highland material has come from recent observations by the Apollo 15 Orbiter. The inferred mineralogy is 45 mole percent high anorthite plagioclase and the parent rocks have an estimated density of 2.94 g cm^–3. The Surveyor 7 chemical composition is the principal contributor to present estimates of the overall chemical composition of the lunar surface.Presented at the NATO Advanced Study Institute on Lunar Studies, Patras, Greece, September 14–25, 1971. This paper is an expanded and updated version of a paper presented at the Apollo 12 Lunar Science Conference, Houston, Texas, January 11–14, 1971, and published in the Proceedings of this Conference (Turkevich, 1971).     

Apollo 12 thermal radiation properties

The spectral and total thermal radiation properties as a function of bulk density are presented for lunar fines from the Apollo 12 mission. The total emittance is presented as a function of temperature from 90 to 400°K and the solar reflectance (albedo) for near normal incidence.This research was supported by the National Aeronautics and Space Administration under Grant NGR 18-001-060.     

Local lunar topography from the Apollo 17 Alse radar imagery and altimetry

The Apollo 17 ALSE VHF radar provided imagery and continuous profiling data around the Moon during two revolutions. The imagery data are used to derive depth and diameter measurements of small craters (diameter <30 km). The profiling data are used to study the topography of a few large craters: the bulged floors in Hevelius, Neper, and Aitken; central peaks in Neper and Buisson; and the depressed floor of Maraldi. The same data provided accurate (better than 25 m) profiles of Mare Crisium and Mare Serenitatis.     

Thermal radiation properties of Apollo 14 fines

The thermal radiation properties as a function of bulk density, angle of illumination and wavelength are presented for lunar fines from the Apollo 14 mission. The density range covered is from 1095 kg/m³ to 1590 kg/m³ and a wavelength range of 0.36–14.5 μm. The solar albedo and total emittance were calculated from spectral values and are compared to Apollo 11 and 12 values.     

The magnetic characteristics of returned lunar samples and 5heir implications for regolith processes

Magnetic observations yield information about the amount and nature of the magnetic phases present in a sample. They reveal that the predominant magnetic phase in the lunar samples is metallic iron which is sometimes alloyed with nickel and cobalt. In the mare basalts less than 0.1% of metallic iron is present, whereas in the non-mare crystalline rocks several percent of iron has been found in some samples. The soils have approximately 0.5% of iron, which is fine grain, rather pure iron occurring in impact glass. In the recrystallized breccias and the igneous rocks the iron is coarser. Systematic minor variations in metallic iron content in the soils reveal soil maturity trends. Mixing between highland and mare soils can be traced with the Fe²⁺ content. Mare soils differ from highland soils in having a higher value of reduced remanence. The magnetic characteristics of the Apollo 14 breccias are not consistent with the progressive metamorphism of a common starting material. Shock welding in the range of tens of kbs can account for the characteristics of some of the ‘unmetamorphosed’ breccias. Greater shock accompanied by recovery can account for the magnetic characteristics of the ‘recrystallized’ breccias.     

Infrared and Raman spectra of lunar samples from Apollo 11, 12 and 14

We report the room temperature infrared reflectance spectra of several lunar surface rocks in the form of polished slices or butt ends. The spectra were obtained over the frequency range 20-2000 cm^–1 throughout the mid and far infrared (5-500µ) region of the electromagnetic spectrum where the fundamental internal and lattice vibrational modes of all minerals and rocks occur.Some fines samples were examined as pressed pellets and their reflectivities compared with the bulk samples. Several terrestrial minerals and rocks were also investigated. Kramers-Kronig analyses of these reflectance spectra were undertaken and the dispersion of the dielectric response ( and ) and the optical constants (n andk) have been determined over this frequency range. The low frequency and high frequency (infrared) dielectric constants were also calculated from the reflectance data.Raman light scattering measurements were made on all the samples supplied from the first three Apollo missions. Large background scattering proved to be the greatest experimental problem. Successful spectra in nearly all cases were obtained from small crystalline inclusions imbedded in the main ground mass. Some crystalline bulk rocks containing many very fine inclusions gave identifiable spectra and at least three different types were obtained.Supported by NASA Grant NGR 22-011-069 and by a Northeastern University Grant for Basic Research.     

An analysis of Apollo lunar soil samples 12070,889, 12030,187, and 12070,891: Basaltic diversity at the Apollo 12 landing site and implications for classification of small‐sized lunar samples

Lunar mare basalts provide insights into the compositional diversity of the Moon's interior. Basalt fragments from the lunar regolith can potentially sample lava flows from regions of the Moon not previously visited, thus, increasing our understanding of lunar geological evolution. As part of a study of basaltic diversity at the Apollo 12 landing site, detailed petrological and geochemical data are provided here for 13 basaltic chips. In addition to bulk chemistry, we have analyzed the major, minor, and trace element chemistry of mineral phases which highlight differences between basalt groups. Where samples contain olivine, the equilibrium parent melt magnesium number (Mg#; atomic Mg/[Mg + Fe]) can be calculated to estimate parent melt composition. Ilmenite and plagioclase chemistry can also determine differences between basalt groups. We conclude that samples of approximately 1–2 mm in size can be categorized provided that appropriate mineral phases (olivine, plagioclase, and ilmenite) are present. Where samples are fine‐grained (grain size <0.3 mm), a “paired samples t‐test” can provide a statistical comparison between a particular sample and known lunar basalts. Of the fragments analyzed here, three are found to belong to each of the previously identified olivine and ilmenite basalt suites, four to the pigeonite basalt suite, one is an olivine cumulate, and two could not be categorized because of their coarse grain sizes and lack of appropriate mineral phases. Our approach introduces methods that can be used to investigate small sample sizes (i.e., fines) from future sample return missions to investigate lava flow diversity and petrological significance.     

Experimental and petrological constraints on lunar differentiation from the Apollo 15 green picritic glasses

Abstract— Phase equilibrium experiments on the most magnesian Apollo 15C green picritic glass composition indicate a multiple saturation point with olivine and orthopyroxene at 1520°C and 1.3 GPa (about 260 km depth in the moon). This composition has the highest Mg# of any lunar picritic glass and the shallowest multiple saturation point. Experiments on an Apollo 15A composition indicate a multiple saturation point with olivine and orthopyroxene at 1520°C and 2.2 GPa (about 440 km depth in the moon). The importance of the distinctive compositional trends of the Apollo 15 groups A, B, and C picritic glasses merits the reanalysis of NASA slide 15426,72 with modern electron microprobe techniques. We confirm the compositional trends reported by Delano (1979, 1986) in the major element oxides SiO₂, TiO₂, Al₂O₃, Cr₂O₃, FeO, MnO, MgO, and CaO, and we also obtained data for the trace elements P₂O₅, K₂O, Na₂O, NiO, S, Cu, Cl, Zn, and F. Petrogenetic modeling demonstrates that the Apollo 15 A‐B‐C glass trends could not have been formed by fractional crystallization or any continuous assimilation/fractional crystallization (AFC) process. The B and C glass compositional trends could not have been formed by batch or incremental melting of an olivine + orthopyroxene source or any other homogeneous source, though the A glasses may have been formed by congruent melting over a small pressure range at depth. The B compositional trend is well modeled by starting with an intermediate A composition and assimilating a shallower, melted cumulate, and the C compositional trend is well modeled by a second assimilation event. The assimilation process envisioned is one in which heat and mass transfer were separated in space and time. In an initial intrusive event, a picritic magma crystallized and provided heat to melt magma ocean cumulates. In a later replenishment event, the picritic magma incrementally mixed with the melted cumulate (creating the compositional trends in the green glass data set), ascended to the lunar surface, and erupted as a fire fountain. A barometer created from multiple saturation points provides a depth estimate of other glasses in the A‐B‐C trend and of the depths of assimilation. This barometer demonstrates that the Apollo 15 A‐B‐C trend originated over a depth range of ?460 km to ?260 km within the moon.     

Dielectric properties of lunar surface

Measurements of the dielectric characteristics of lunar soil samples are analyzed in the context of dielectric theory. It has been shown that the real component of the dielectric permittivity and the loss tangent of rocks greatly depend on the frequency of the interacting electromagnetic field and the soil temperature. It follows from the analysis that one should take into account diurnal variations in the lunar surface temperature when interpreting the radar-sounding results, especially for the gigahertz radio range.     

Physical properties of lunar craters

The surface of the Moon is highly cratered due to impacts of meteorites, asteroids, comets and other celestial objects. The origin, size, structure, age and composition vary among craters. We study a total of 339 craters observed by the Lunar Reconnaissance Orbiter Camera(LROC). Out of these 339 craters, 214 craters are known(named craters included in the IAU Gazetteer of Planetary Nomenclature) and 125 craters are unknown(craters that are not named and objects that are absent in the IAU Gazetteer). We employ images taken by LROC at the North and South Poles and near side of the Moon. We report for the first time the study of unknown craters, while we also review the study of known craters conducted earlier by previous researchers. Our study is focused on measurements of diameter, depth, latitude and longitude of each crater for both known and unknown craters. The diameter measurements are based on considering the Moon to be a spherical body. The LROC website also provides a plot which enables us to measure the depth and diameter. We found that out of 214 known craters, 161 craters follow a linear relationship between depth(d) and diameter(D), but 53 craters do not follow this linear relationship. We study physical dimensions of these 53 craters and found that either the depth does not change significantly with diameter or the depths are extremely high relative to diameter(conical). Similarly, out of 125 unknown craters, 78 craters follow the linear relationship between depth(d) and diameter(D) but 47 craters do not follow the linear relationship.We propose that the craters following the scaling law of depth and diameter, also popularly known as the linear relationship between d and D, are formed by the impact of meteorites having heavy metals with larger dimension, while those with larger diameter but less depth are formed by meteorites/celestial objects having low density material but larger diameter. The craters with very high depth and with very small diameter are perhaps formed by the impact of meteorites that have very high density but small diameter with a conical shape. Based on analysis of the data selected for the current investigation, we further found that out of 339 craters, 100(29.5%) craters exist near the equator, 131(38.6%) are in the northern hemisphere and 108(31.80%) are in the southern hemisphere. This suggests the Moon is heavily cratered at higher latitudes and near the equatorial zone.     

A reanalysis of the Apollo light scattering observations, and implications for lunar exospheric dust

Conspicuous excess brightness, exceeding that expected from coronal and zodiacal light (CZL), was observed above the lunar horizon in the Apollo 15 coronal photographic sequence acquired immediately after orbital sunset (surface sunrise). This excess brightness systematically faded as the Command Module moved farther into shadow, eventually becoming indistinguishable from the CZL background. These observations have previously been attributed to scattering by ultrafine dust grains (radius ∼0.1 microns) in the lunar exosphere, and used to obtain coarse estimates of dust concentration at several altitudes and an order-of-magnitude estimate of ∼10⁻⁹ g cm⁻² for the column mass of dust near the terminator, collectively referred to as model “0”.We have reanalyzed the Apollo 15 orbital sunset sequence by incorporating the known sightline geometries in a Mie-scattering simulation code, and then inverting the measured intensities to retrieve exospheric dust concentration as a function of altitude and distance from the terminator. Results are presented in terms of monodisperse (single grain size) dust distributions. For a grain radius of 0.10 microns, our retrieved dust concentration near the terminator (∼0.010 cm⁻³) is in agreement with model “0” at z=10 km, as is the dust column mass (∼3–6×10⁻¹⁰ g cm⁻²), but the present results indicate generally larger dust scale heights, and much lower concentrations near 1 km (<0.08 cm⁻³ vs. a few times 0.1 cm⁻³ for model “0"). The concentration of dust at high altitudes (z>50 km) is virtually unconstrained by the measurements. The dust exosphere extends into shadow a distance somewhere between 100 and 200 km from the terminator, depending on the uncertain contribution of CZL to the total brightness. These refined estimates of the distribution and concentration of exospheric dust above the lunar sunrise terminator should place new and more rigorous constraints on exospheric dust transport models, as well as provide valuable support for upcoming missions such as the Lunar Atmosphere and Dust Environment Explorer (LADEE).     

Searching for nonlocal lithologies in the Apollo 12 regolith: A geochemical and petrological study of basaltic coarse fines from the Apollo lunar soil sample 12023,155

New data from a petrological and geochemical examination of 12 coarse basaltic fines from the Apollo 12 soil sample 12023,155 provide evidence of additional geochemical diversity at the landing site. In addition to the bulk chemical composition, major, minor, and trace element analyses of mineral phases are employed to ascertain how these samples relate to the Apollo 12 lithological basalt groups, thereby overcoming the problems of representativeness of small samples. All of the samples studied are low‐Ti basalts (0.9–5.7 wt% TiO₂), and many fall into the established olivine, pigeonite, and ilmenite classification of Apollo 12 basaltic suites. There are five exceptions: sample 12023,155_1A is mineralogically and compositionally distinct from other Apollo 12 basalt types, with low pigeonite REE concentrations and low Ni (41–55 ppm) and Mn (2400–2556 ppm) concentrations in olivine. Sample 12023,155_11A is also unique, with Fe‐rich mineral compositions and low bulk Mg# (=100 × atomic Mg/[Mg+Fe]) of 21.6. Sample 12023,155_7A has different plagioclase chemistry and crystallization trends as well as a wider range of olivine Mg# (34–55) compared with other Apollo 12 basalts, and shows greater similarities to Apollo 14 high‐Al basalts. Two other samples (12023,155_4A, and _5A) are similar to the Apollo 12 feldspathic basalt 12038, providing additional evidence that feldspathic basalts represent a lava flow proximal to the Apollo 12 site rather than material introduced by impacts. We suggest that at least one parent magma, and possibly as many as four separate parent magmas, are required in addition to the previously identified olivine, pigeonite, and ilmenite basaltic suites to account for the observed chemical diversity of basalts found in this study.