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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 91 records · Page 5
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NASA NTRS1973

Mechanical erasure of particle tracks - A tool for lunar microstratigraphic chronology.

Mechanical erasure of particle tracks caused by impact deformation is shown to be a common feature of lunar soil grains. Etching of lunar pyroxenes reveals deformation markings that are evidence of prior impact events. The soil microstratigraphic chronology can be derived if it is assumed that the minimum track density in a thin soil layer is commonly found in grains where such erasure was caused by the impact that deposited the soil. With Apollo 12 core samples as examples, the minimum track density found in each layer is used to calculate the longest exposure that layer could have received since it was last disturbed. By summing the upper limits on the exposure times of the different layers, a lower limit on the average deposition rate was estimated to be 0.35 cm/m.y.

Fleischer, R. L.↗
NASA NTRS1973

The Apollo spacecraft: A chronology. Volume 2: 8 November 1962 - 30 September 1964

A chronology of the Apollo spacecraft development and production program is presented. The subjects discussed are: (1) defining contractural relations, (2) developing hardware distinctions, and (3) developing software ground rules. Illustrations, drawings, and photographs are used extensively to supplement the technical writing. Descriptions of life support systems, communication equipment, propulsion systems, control devices, and spacecraft components are provided.

Morse, M. L.↗
NASA NTRS1975

Astronautics and aeronautics, 1973: Chronology of science, technology and policy

A brief chronological account is presented of key events of the year in aerospace sciences. Dates, actions, hardware, persons, scientific discoveries are recorded along with plans, decisions, achievements and preliminary evaluations of results. Samples of public reaction and social impact are included. Sources are identified and an index is provided to aid in tracing related events through the year. The index also serves as a glossary of acronyms and abbreviations.

Source record↗
NASA NTRS1977

Outline of a lunar chronology

An outline is presented of lunar chronology and evolution based on analyses of the isotopic parent-daughter systems Rb-87-Sr-87, U-Th-Pb-206-Pb-207-Pb-208, and K-40-Ar-40. The samples which were investigated represent mare basalts (returned by Apollo 11, 12, 15, and 17 and by Luna 16) and terra rocks which include non-mare basalts, anorthosites, troctolites, and norites, but are predominantly comprised of complex breccias (returned by Apollo 12, 14, 16, and 17 and Luna 20)

Wasserburg, G. J.↗
NASA NTRS1976

Chronology of the early lunar crust

The Rb-Sr systematics of lunar 'anorthositic' rocks was studied in an effort to understand the evolution of the lunar crust. The contamination by KREEP of the anorthositic crust is corrected using chemical mixing models; cumulate geochemical models are used to establish the chronology of the early lunar crust; a method is presented to derive an estimate of the Rb/Sr ratio of the moon. A mathematical model for the Rb-Sr evolution of the lunar crust that includes mare basalt genesis is presented.

Schonfeld, E.↗
NASA NTRS1977

Lunar Rb-Sr chronology

It has been established with the aid of Rb-Sr studies that lunar chronology consists of five episodes, including the formation of the moon approximately 4.6 AE ago (1 AE = 1000 million years), a period of intense bombardment by planetary debris resulting in the formation of the major lunar basins, the end of this period at 3.9-4.0 AE ago, a period of mare flooding extending from 3.9 to 3.2 AE ago, and a relatively quiescent period from 3.2 AE ago to the present. In addition, Rb-Sr-studies have provided valuable constraints on the geochemical evolution of the moon through the determination of the initial Sr-87/Sr-86 ratios which limit the Rb/Sr ratios of the source materials for lunar rocks. Attention is given to the characteristics of the Rb-Sr method, the analytical techniques, the ages of lunar mare basalts, the non-mare rocks, the studies conducted in connection with the various Apollo missions, the lunar cataclysm, lunar soils, and aspects of crustal contamination.

Nyquist, L. E.↗
NASA NTRS1978

The Apollo spacecraft: A chronology volume 4, 21 January 1966 - 13 July 1974

This final volume of the chronology is divided into three parts: (1) preparation for flight, the accident, and investigation; (2) recovery, spacecraft redefinition, and the first manned flight; and (3) man circles the moon, the Eagle lands, and manned space exploration. Congressional documents, official correspondence, government and contractor reports, memoranda, working papers, and minutes of meetings were used as primary sources. A relatively few entries are based on press releases and newspaper and magazine articles.

Ertel, I. D.↗
NASA NTRS1979

The chronology of the martian volcanoes

The volcanoes of Mars have been divided into three groups based on morphology: basaltic shields, domes and composite cones, and highland patera. A fourth group can be added to include the volcano-tectonic depressions. Using crater counts and the absolute chronology of Soderblom, an attempt is made to estimate the history of the volcanoes. Early in the martian history, about 2.5 b.y. ago, all three styles of volcanoes were active at various locations on the surface. At approximately 1.7-1.8 b.y. ago a transition occurred in the style and loci of volcanic construction. Volcanoes of younger age appear to be only of the basaltic shield group and are restricted to the Tharsis region. This same transition was noted by a change in the style of the basaltic shield group. Older shields were small low features, while the younger shields are significantly broader and taller.

Plescia, J. B.↗
NASA NTRS1982

Chronology and petrogenesis of young achondrites, Shergotty, Zagami, and ALHA77005 - Late magmatism on a geologically active planet

Three achondrites were examined for chronology, petrogenesis, and relationships among the shergotites. Isotopic and trace elements analyses were carried out through neutron activation and mass spectrometry on Shergotty, Zagami, and ALHA77005 samples. Attention was given the Rb-Sr, Sm-Nd, and the Ar-39/Ar-40 ages in the samples. Evidence was detected for a shock metamorphism and a younger age of the meteorites than with most other achondrites. Depletions of the rare-earth elements were observed in Shergotty and Zagami, and to a more pronounced degree in ALHA77005. The Rb-Sr internal isochrons for all three meteorites were about 180 Myr, while the Ar-39/Ar-40 plateau ages of Shergotty and Zagami maskelynite were determined at 250-260 Myr. No precise identification of the crystallization ages was found. It is suggested that the achondrites originated in a parent body which experienced at least two epochs of sustained melting.

Shih, C.-Y.↗
NASA NTRS1983

Importance of the Lu-Hf isotopic system in studies of planetary chronology and chemical evolution

The Lu-176-Hf-176 isotope method and its applications in earth sciences are discussed with regard to planetary-evolution studies. From new data on basalts from oceanic islands, Hf-176/Hf-177 and Nd-143/Nd-144 are found to display a single linear isotopic variation in the suboceanic mantle, whereas considerable divergences occur in Hf-176/Hf-177-Sr-87/Sr-86 and Nd-143/Nd-144-Sr87/Sr-86 diagrams. With the acquisition of further Hf-Sr-Nd isotopic data, these discordant Sr-87/Sr-86 relationships may allow a distinction between processes such as mantle metasomatism, influence of sea-water altered material in the magma source, or recycling of sediments into the mantle. The best quality Hf isotope data are obtained from granitoid or zircons, and are most suitable for studying ancient terrestrial Hf isotopic variations. Lu-Hf is shown to be a viable method for dating ancient terrestrial and extraterrestrial samples, but is unlikely to find wide application in pure chronological studies because it offers little advantage over existing methods.

Patchett, P. J.↗
NASA NTRS1984

Chronology of KSC and KSC related events, 1982

The history of activities at the Kennedy Space Center in 1982 is presented as reflected in NASA News Releases and selected periodicals. Items are arranged in chronological order by date of the published sources. Actual data date of the event may be indicated in parenthesis when the article itself does not make that information explicit. Highlights of the year's activities include three launchings of the orbiter Columbia; successful launches of communications satellites using expendable vehicles; major changes in contracting; and the selection of a base operations contractor.

Nail, K., Jr.↗
NASA NTRS1984

Astronautics and aeronautics, 1976. A chronology

A chronology of events concerning astronautics and aeronautics for the year 1976 is presented. Some of the many and varied topics include the aerospace industry, planetary exploration, space transportation system, defense department programs, politics, and aerospace medicine. The entries are organized by the month and presented in a news release format.

Ritchie, E. H.↗
NASA NTRS1984

Chronology of KSC and KSC related events for 1983

Materials for this chronology were selected from Aviation Week and Space Technology, Defense Daily, Miami Herald, Sentinel Star (Orlando), Today (Cocoa), Spaceport News (KSC), NASA News Releases, and other sources. The document is intended to serve as a record of KSC events and as a reference source for historians and other researchers. Arrangement is by month; items are by date of the published sources. Actual date of the event may be indicated in parenthesis, when the article itself does not make that information explicit.

Nail, K., Jr.↗
NASA NTRS1985

Chronology of warm-core ring 82B

The chronology presently derived from satellite thermal imagery to describe the formation and life history of the warm core ring 82B furnishes insight into a classification of features and discrete events associated with Gulf Stream warm core rings; these events are thereby put in a broader spatial and temporal context. The interactions of the ring with surrounding waters are noteworthy, and the existence of vortex-vortex interactions is shown to be a significant cause of local water advection through streamer activity. Acoustic velocity profiling and drifter trajectories have been used to corroborate hydrographic features of the ring and its environs.

Evans, R. H.↗
NASA NTRS1985

Geometric and chronologic evolution of the Verde and Payson Basins of Central Arizona and possible relationships to detachment faulting

The Transition Zone of Arizona and the structural basins therein have been poorly understood features from a structural standpoint. This is true both of their overall geometry as well as their formation. Yet these basins have developed within the last 13 million years and thus represent perhaps the most recent phase of development related to the extensional tectonics of the Basin and Range province. Recent work (Smith, 1984; Vance, 1983) as well as some older studies (Anderson and Creasy, 1985; Pedersen and Royce, 1970) provide data on the geometry of the Verde and Payson basins which can be used to constrain some hypotheses related to the development of these basins. The work of Cloos (1868), Anderson et. al. (1983), Wernicke and Burchfiel (1982) and Davis et. al. (l980) suggest a spatial and chronologic relation exists between planar high angle normal faults and low angle detachment faults. Perhaps one of the clearest examples from the Basin and Range area appears to be from seismic reflection profiles of the Sevier Desert Basin area of Utah (Fig. 1). These profiles suggest the existence fault-controlled extension basin development above it. Faults that appear either listric or planar intersect it from above.

Brumbaugh, D. S.↗
NASA NTRS1986

Chronology and isotopic geochemistry of apollo 14 basalts and Skaergard Gabbro, Eastern Greenland

Work completed on Apollo 14 basalts has been published. The two dates obtained from these rocks comprised the oldest and two of the three oldest ages (4.1 and 4.3 billion years) known for lunar maria basalts; thus their ages are important in understanding the moon's earliest history. Owing to the antiquity of these rocks, two more fragments have been dated as part of a second ASEE/NASA SFF program. The new ages are 3.95 and 4.12 billion years, thus further establishing and amplifying the earlier results. This work, although perhaps more interesting for its chronologic information, was begun as a test of chemical and petrographic models. Fragments of Apollo basalt were placed into five categories, based on petrologic and chemical, especially rare-earth element, composition. Isotopic studies were begun in an attempt to determine if the five groups of basalts were related by age or initial isotopic composition (isotopic composition of lava at time of extrusion). Although a few of the representatives of the five groups have the same age and/or initial strontium-isotopic composition, within the analtytical uncertainties, most apparently are unrelated. Petrologic implications of these data will be published in an appropriate journal.

Dasch, E. J.↗