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At least 1,459 records · Page 81
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Lunar anorthosite 15415 - Texture, mineralogy, and metamorphic history.

Lunar anorthosite 15415 consists almost entirely of anorthite (homogeneous anorthite 96.6 molecule percent), with accessory diopsidic augite and traces of hypersthene, ilmenite, and a silica mineral. The rock has had a complex metamorphic history. The texture reflects at least two episodes of shearing (followed by intense and partial recrystallization, respectively), one episode of cataclastic deformation, and one or more episodes of shattering and fragmentation.

James, O. B.↗
NASA NTRS1971

Mass spectral analysis of C3 and C4 aliphatic amino acid derivatives.

Diagnostic criteria are obtained for the distinction of alpha, beta, gamma, and N-methyl isomers of the C3 and C4 aliphatic amino acids, using mass spectral analysis of the derivatives of these acids. The use of deuterium labeling has helped in the understanding of certain fragmentation pathways.

Lawless, J. G.↗
NASA NTRS1971

Photoionization of methanol and formaldehyde

Photoions produced in methanol and formaldehyde by radiation in the spectral region 450-1150 A were analyzed mass spectrometrically, and their relative yields were determined as a function of wavelength. First ionization potentials were determined, and the ion yield curves were interpreted in terms of ionization processes in conjunction with other data. Fragment ions were detected on mass numbers of 31, 30, 29, 15, and 14 for methanol, and 29, 2, and 1 for formaldehyde. The associated appearance potentials were determined and were used to calculate heats of formation of the ions CH2OH(+) and HCO(+), and the radicals CH3, CH2, and HCO.

Warneck, P.↗
NASA NTRS1972

Rb-Sr age of a Luna 16 basalt and the model age of lunar soils.

An internal isochron was determined on a small basalt fragment (sample B-1) returned from the Luna 16 mission, which yields an age of 3.42 plus or minus 0.8 b.y. and a low initial Sr87/Sr86 value. A comparison is made of the data from four lunar missions to mare sites which shows that the last period of major flooding of the mare basins is confined to a narrow time interval of only 0.55 b.y. The direct evidence of major lunar magmatic activity appears to be confined to the interval from 3.1 to 4.0 b.y. The Sr87/Sr86 values for all mare basalts are extremely primitive and lie in a rather narrow range. A diagram is given for initial Sr87/Sr86 as a function of time for all lunar rocks.

Papanastassiou, D. A.↗
NASA NTRS1972

Evidence for amino-acids of extraterrestrial origin in the Orgueil meteorite.

The problems of separation of contaminant from indigenous amino-acids in meteorites can be largely overcome by applying gas chromatographic techniques for the separation of D,L enantiomers of amino-acids as their diastereomeric derivatives and the identification of these compounds by gas chromatographic retention times and mass spectral fragmentation patterns. Two samples of Orgueil meteorite were examined. The results show that there are amino-acids indigenous to the Orgueil meteorite in addition to those present as contaminants.

Lawless, J. G.↗
NASA NTRS1971

Chemical composition of lunar anorthosites and their parent liquids.

Data obtained in a trace element analysis of some anorthosite and anorthositic fragments are presented. The low Mg concentrations of the Apollo 15 anorthosite and the KREEP anorthosite reflect the mineralogical purity of these samples. They are so pure that their composition can be taken as that of liquidus plagioclases. Some of the characteristics of the parent liquids of these plagioclases can be calculated from the liquid-plagioclase distribution coefficients.

Hubbard, N. J.↗
NASA NTRS1972

Geologic setting and petrology of Apollo 15 anorthosite /15415/.

The geological setting, petrography and history of this Apollo 15 lunar rock sample are discussed, characterizing the sample as coarse-grained anorthosite composed largely of calcic plagioclase with small amounts of three pyroxene phases. The presence of shattered and granulated minerals in the texture of the rock is traced to two or more fragmentation events, and the presence of irregular bands of coarsely recrystallized plagioclase and minor pyroxene crossing larger plagioclase grains is traced to an earlier thermal metamorphic event. It is pointed out that any of these events may have affected apparent radiometric ages of elements in this rock. A comparative summarization of data suggests that this rock is the least-deformed member of a suite of similar rocks ejected from beneath the regolith at Spur crater.

Wilshire, H. G.↗
NASA NTRS1972

Lunar zirkelite - A uranium-bearing phase.

Zirkelite (simplified CaZrTiO5) containing 7-17 wt % oxides of trivalent elements (largely yttrium and the rare earths) and minor amounts of U, Th, and Pb is described from an Apollo 12 feldspathic peridotite (12036,9) and two KREEP-type norite lithic fragments separated from Apollo 14 loose fines (14163,39 and 14257,3). Quantitative electron microprobe analyses indicate that this lunar phase conforms more closely to the zirkelite formula than the zirconolite formula.

Busche, F. D.↗
NASA NTRS1972

Glass in the bottom of small lunar craters - An observation from Apollo 15.

The origin of glazed rock fragments and glassy splatter in the bottom of fresh, 0.5- to 3.0-m-diameter lunar craters has been the subject of much debate. Evidence presented from Apollo 15 data indicates that one such crater, with an associated glass-coated projectile, is of low velocity, 'secondary' origin. It is shown that, for the crater examined, the glassy material cannot have been formed in situ by impact fusion due to the low energy involved. It is suggested that the glass in many such craters may be carried as a semi-liquid or solidified coating on incoming rock projectiles ejected from local primary impact craters of larger size.

Schaber, G. G.↗
NASA NTRS1972

Fracture of boron filaments in an aluminum matrix.

The B-Al composite specimens tested in this study were fabricated by diffusion bonding of 1230 aluminum foil and boron filaments placed in alternate layers, using an acrylic resin solution to maintain filament spacing. The specimens were put under tensile stresses parallel to the filaments, and filament fracture was monitored acoustically under loads. Fracture of specimens under loads was caused by break propagation with a characteristic wedge-type fragmentation pattern indicating its direction. The aluminum foil matrix of the specimens failed by ductile shear type fracture after the break of the filaments.

Steele, J. H.↗
NASA NTRS1972

Morphology and petrography of volcanic ashes.

Study of volcanic ash samples collected from a variety of recent eruptions using petrography, chemical analyses, and scanning electron microscopy to characterize each type and to relate ash morphology to magma composition and the type of eruption. The ashes are placed in the broad genetic categories of magmatic and phreatomagmatic. The morphology of ash particles from magmatic eruptions of high viscosity magma is governed primarily by vesicle density and shape. Ash particles from eruptions of low viscosity magmas are mostly droplets. The morphology of ash particles from phreatomagmatic eruptions is controlled by stresses within the chilled magma which result in fragmentation of the glass to form small blocky or pyramidal glass ash particles.

Heiken, G.↗
NASA NTRS1972

Linear momentum transfer effects in molecular dissociation produced by electron impact.

In this study of molecular dissociation produced by electron impact, diatomic systems and polyatomic molecules are considered, and attention is given to the effects of thermal motion and of momentum transfer in the collision process. A procedure is described which makes it possible to 'construct' both the laboratory angular distribution and velocity distribution of the atomic fragments (or, alternatively, the time-of-flight distribution). The calculation assumes that s-wave electron scattering predominates, i.e., that excitation occurs near threshold. The computational procedure may also be reversed to allow construction of possible molecular models to fit given experimental angular and velocity distribution data.

Misakian, M.↗
NASA NTRS1973

Ion masking improves resolution in quadrupole mass spectrometers

Mass spectrometers analyze molecular composition by determining mass-to-charge ratio of ion fragments of molecules. Study adds significantly to quantitative understanding of quadrupole mass filter. It includes development of quantitative theory of ion oscillations, computer analysis of ion behavior, and identification of determining factors in peak tail size.

Ierokomos, N.↗
NASA NTRS1972

Manned space flight nuclear system safety. Volume 4: Space shuttle nuclear system transportation. Part 1: Space shuttle nuclear safety

An analysis of the nuclear safety aspects (design and operational considerations) in the transport of nuclear payloads to and from earth orbit by the space shuttle is presented. Three representative nuclear payloads used in the study were: (1) the zirconium hydride reactor Brayton power module, (2) the large isotope Brayton power system and (3) small isotopic heat sources which can be a part of an upper stage or part of a logistics module. Reference data on the space shuttle and nuclear payloads are presented in an appendix. Safety oriented design and operational requirements were identified to integrate the nuclear payloads in the shuttle mission. Contingency situations were discussed and operations and design features were recommended to minimize the nuclear hazards. The study indicates the safety, design and operational advantages in the use of a nuclear payload transfer module. The transfer module can provide many of the safety related support functions (blast and fragmentation protection, environmental control, payload ejection) minimizing the direct impact on the shuttle.

Source record↗
NASA NTRS1972

Multidisciplinary research leading to utilization of extraterrestrial resources

Progress of the research accomplished during fiscal year 1972 is reported. The summaries presented include: (1) background analysis and coordination, (2) surface properties of rock in simulated lunar environment, (3) rock failure processes, strength and elastic properties in simulated lunar environment, (4) thermal fragmentation, and thermophysical and optical properties in simulated lunar environment, and (5) use of explosives on the moon.

Source record↗
NASA NTRS1972

Evidence from Stream Meteoroids

The physical behavior and composition of shower meteors were examined in an effort to establish the structure of its parent comet. Properties considered include degree of fragmentation and density.

Mccrosky, R. E.↗
NASA NTRS1972

Phenomena after meteoroid penetration of a bumper plate

The results are presented of a study to obtain a computer program for the penetration of a thin plate of aluminum by a sphere of rock. The study was divided into two projects. One project covers the initial impact, the crushing of the sphere of rock, the break up of the aluminum sheet, and the conversion of the sufficiently shock-compressed regions of rock and aluminum into a plasma. The other project considers the ejection of a cone of plasma with entrained particles from the impact zone, its expansion as it traverses a region of free space, and its impact on a stack of paper sheets. The ablation of fragments in penetrating the stack of paper sheets is also considered.

Todd, F. C.↗