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At least 325 records · Page 18

Results of investigating thermal and electrical properties of lunar surface material and its analogs

Thermal and electrical properties are reported of lunar surface material returned to Earth by the Luna 16 automatic station and its terrestrial analogs studied in a vacuum and in a helium atmosphere. Study of the lunar surface material and its analogs showed that their specific heat capacity and electrical properties are similar in value but the coefficients of thermal conductivity differ. The results are compared with data on thermal and electrical properties of the surficial layer of the Moon obtained by indirect radiometric methods, and with results obtained for samples of lunar surface material returned to Earth by the crew of the Apollo 11 spacecraft.

Golovkin, A. R.↗

Results of investigating the physicomechanical properties of a sample of lunar surface material in a research chamber in nitrogen

Results are reported on an investigation of the mechanical properties of the lunar surface material sample returned by the Luna 16 automatic station. The study included determination of the specific weight of the surface material, the nature of its disintegration, and the determination of its compressibility characteristics, shear resistance, and bearing capacity. Quantitative data are presented on mechanical properties for the lunar surface material, many of which are determined for the first time. The instruments and experimental techniques are described.

Leonovich, A. K.↗

Study of Friction Properties of Lunar Surface Material and Its Analogs

A description is given of instruments for determining the friction properties of the surficial layer of lunar surface material returned by the Luna 16 automatic lunar station, as well as the friction properties of its analogs: andesite-basaltic sand and basalts. The experimental method and results are presented.

Ye A Dukhovskoy↗

Evolution of the moon: The 1974 model

Investigations are reported of Apollo and Luna explorations which have brought about the understanding of the moon and its structure. It is shown that with this knowledge of the moon, a better understanding is presented of the earth's origin, structure and composition.

Schmitt, H. H.↗

Petrology of basalt and single-mineral fragments in the soil of the Sea of Fertility

Basalt and single-mineral particles, ranging from 150 to 425 microns, from the Luna-16 sample are studied by electron microanalysis, X-ray fluorescence analysis, and petrographic techniques. Three basalt species of different structure are identified. The structure and composition of the individual minerals (in particular of pyroxenes) indicate that the basalts have crystallized under conditions similar to those established for Apollo-11 samples.

Bence, A. E.↗

Feldspar basalts in lunar soil and the nature of the lunar continents

It is found that 25% on the Apollo-14 glasses have the same composition as the glasses in two samples taken from the Luna-16 column. The compositions are equivalent to feldspar basalt and anorthosite gabbro, and are similar to the feldspar basalts identified from Surveyor-7 analysis for lunar continents.

Reid, A. M.↗

K and U systematics and average concentrations on the moon

The K-U, Th-U, and Th-Al systematics for lunar samples from the Apollo 11-17 missions and the Luna 16 and 20 missions are summarized. With few exceptions (granitic portion of 12013 and the Apollo 17 mare basalts) the Th/U ratio is 3.8 plus or minus 0.2. The K/U ratio for lunar samples is about 2600 and is distinctly different from the K/U ratio found in terrestrial samples and in the majority of meteorites. The K-U systematics are similar to the K-La, K-Sm, K-Ba, and K-Zr systematics, suggesting that the moon accreted approximately homogeneously. Based on a model the moon contains an average abundance of about 80 ppb U, about 200 ppm K, and about 7 times chondritic abundances for all the refractory elements such as Al, Ca, Ti, Zr, Ba, Sr, and REE. The Th-Al systematics of many lunar highland rocks are dominated by the presence of the rock-type KREEP.

Schonfeld, E.↗

Early active sun - Radiation history of distinct components in fines

Plagioclase feldspars were separated from lunar soil samples and their compositions were determined by electron-microprobe analysis followed by etching and track counting in an effort to find effects of early solar activity. The feldspars were assigned on this basis to three major lithologies: mare basalts, anorthositic rocks, and KREEP rock. The results are in sharp contrast to Poupeau et al.'s (1973) observations on track densities in plagioclase crystals in the Luna 16 soil: no evidence is found for an early active sun, although the evidence does not preclude this possibility, either.

Crozaz, G.↗

Petrology of lunar soils

The paper summarizes the physical and petrographic characteristics of the finer-grained fractions (less than 1 cm) of lunar regolith soil in Apollo and Luna samples. Lunar soils are poorly sorted and consist mostly of lithic and mineral debris derived by impact comminution of the underlying bedrock and glass particles formed by impact melting. Agglutinates constitute an important soil component and are key factors in the genetic history of lunar soil. Some models concerning the development of lunar regolith based on soil studies are examined.

Heiken, G.↗

Mare basalts - Crystal chemistry, mineralogy, and petrology

The paper attempts a synthesis of the major-element chemistry, petrography, mineral chemistry, and crystal chemistry of the mare basalts returned by Apollo and Luna missions. A classification of the mare basalts based on major-element chemistry is given, and textural sequences within each major-element group are identified. The mineral chemistry and crystal chemistry of each mineral group are considered within the framework of the major-element groups and the textural sequences. The various classes of models for the origin of the mare basalts and the nature of their source regions are discussed in the context of the major- and trace-element chemistries and experimental investigations.

Papike, J. J.↗

Notes on Soviet space astronomy

Soviet space programs intended for making astronomical observations are reviewed. The Cosmos, Intercosmos, and Prognoz satellites designed for astronomical measurements are identified, and unmanned lunar and planetary missions are discussed, including the Luna, Lunokhod, Mars, and Venera programs. The Salyut 4 space station is described in detail along with the following major astronomical instruments: the Orbiting Solar Telescope 1, the infrared telescope spectrometer, the two solar spectrometers, the light-nuclei mass spectrometer, and the Filin and RT-4 X-ray telescopes. The future of Soviet space astronomy is assessed, particularly the tasks of the Salyut 5 station and the scheduled launch of Salyut 6.

Oberg, J. E.↗

What's new on the moon. I

The article gives a general discussion of the state of knowledge concerning the composition, structure, and history of the moon, with attention focused on the new data obtained from the study of the results of Apollo and Luna experiments. The general characteristics of the lunar rocks are mentioned and compared with those of the earth. A possible structure for the lunar interior, as revealed by data on moonquakes, heat flow measurements, and meteorite impacts is sketched. A scenario for the history of the moon is outlined.

French, B. M.↗

Pyroxene-spinel intergrowths in lunar and terrestrial pyroxenes

The paper describes the oriented intergrowth of spinel and pyroxene in a pigeonite from Luna 20, an augite from Apollo 16 anorthosite 67075, and an orthopyroxene from a spinel lherzolite nodule from the San Quintin volcanic field, Mexico. Using Mo K alpha radiation, photographs were taken of small, hand-picked single-crystals. A mechanism of exsolution is suggested in which the oxygen framework remains intact and spinel nuclei are formed by the migration of cations from interstitial sites and tetrahedral sites in the original non-stoichiometric pyroxene.

Okamura, F. P.↗

Characterization of lunar mare basalt types. I - A remote sensing study using reflection spectroscopy of surface soils

Telescopic reflection spectra of mature mare surfaces are used to identify and characterize major basalt types on the frontside of the moon. The spectra are classified according to (1) continuum slope and (2) near-infrared features. This study indicates that there are major lunar basalt types that are unlikely to have been sampled during the landing missions. Regions of basalt exist in the western maria with a TiO2 content comparable to that of Apollo 11 but with infrared characteristics that indicate a distinctly different composition. Samples from two landing sites, Apollo 12 and Luna 16, may contain fragments of a nearby basalt unit compositionally different from the dominant basalt type of the landing area.

Pieters, C.↗

Very low-Ti mare basalts

Bulk compositions, petrology, and mineralogy of lithic fragments discovered in polished sections of Apollo 17 drill core samples 70007, 70008, and 70009 and Luna 24 soil 24077, 43 are described. The fragments have unambiguous affinities to mare basalts, but are exceptionally low in TiO2 (less than 1.0 wt.% TiO2). Apollo 17 rake sample 78526 is a green glassy rock of similar composition. Together the samples represent a distinct variety of mare basalts. Bulk compositional relationships suggest that they are related to Apollo 15 green glass, but the data do not permit one to discern the precise nature of the relationship. Both fractional crystallization and partial melting models can explain the observed compositional trends.

Taylor, G. J.↗

Evolution of the moon: The 1974 model

The interpretive evolution of the moon can be divided now into seven major stages beginning sometime near the end of the formation of the solar system. These stages and their approximate durations in time are as follows: (1) The Beginning: 4.6 billion years ago, (2) The Melted Shell: 4.6 to 4.4 billion years ago, (3) The Cratered Highlands: 4.4 to 4.1 billion years ago, (4) The Large Basins: 4.1 to 3.9 billion years ago, (5) The Light-colored Plains: 3.9 to 3.8 billion years ago, (6) The Basaltic Maria: 3.8 to 3.0(?) billion years ago, and (7) The Quiet Crust: 3.0(?) billion years ago to the present. The contributions of the Apollo and Luna exploration toward the study of those stages of evolution are reviewed.

Schmitt, H. H.↗

Radioactivity of the moon, planets, and meteorites

Analytical data is summarized for the content of natural radioactive elements in meteorites, eruptive terrestrial rocks, and also in lunar samples returned by Apollo missions and the Luna series of automatic stations. The K-U systematics of samples analyzed in the laboratory are combined with data for orbital gamma-ray measurements for Mars (Mars 5) and with the results of direct gamma-ray measurements of the surface of Venus by the Venera 8 lander. Using information about the radioactivity of solar system bodies and evaluations of the content of K, U, and Th in the terrestrial planets, we examine certain aspects of the evolution of material in the protoplanetary gas-dust cloud and then in the planets of the solar system.

Surkou, Y. A.↗

Basalts from Mare Crisium

The stratified core sample returned from Mare Crisium by the Luna 24 unmanned space probe is composed primarily of a variety of subophitic to ophitic basalt with very low contents of TiO2 and MgO. This consists of clinopyroxene, calcic plagioclase, olivine, and minor amounts of silica, chromite, ulvoespinel, ilmenite, troilite, apatite, and Fe-metal. Granular metabasalts have the same bulk composition, but mineral phases exhibit less compositional variation. Fine-grained impact melts have similar compositions and are apparently derived from these basalts. It is concluded that the basalts, which are chemically distinct from the very-low-titanium basalts found elsewhere on the moon, represent the local surface flows of Mare Crisium. Sparse fragments of an olivine vitrophyre that is low in TiO2 but high in MgO and approaches the composition of the Apollo 15 green glasses may be derived from patches of dark mantling materials 20 km from the landing site.

Ryder, G.↗