Oxygen diffusion in zircon

Science.gov (United States)

Watson, E. B.; Cherniak, D. J.

1997-05-01

Oxygen diffusion in natural, non-metamict zircon was characterized under both dry and water-present conditions at temperatures ranging from 765°C to 1500°C. Dry experiments were performed at atmospheric pressure by encapsulating polished zircon samples with a fine powder of 18O-enriched quartz and annealing the sealed capsules in air. Hydrothermal runs were conducted in cold-seal pressure vessels (7-70 MPa) or a piston cylinder apparatus (400-1000 MPa) on zircon samples encapsulated with both 18O-enriched quartz and 18O water. Diffusive-uptake profiles of 18O were measured in all samples with a particle accelerator, using the 18O(p, α) 15N reaction. For dry experimental conditions at 1100-1500°C, the resulting oxygen diffusivities (24 in all) are well described by: D dry (m 2/s) = 1.33 × 10 -4exp(-53920/T) There is no suggestion of diffusive anisotropy. Under wet conditions at 925°C, oxygen diffusion shows little or no dependence upon P H 2O in the range 7-1000 MPa, and is insensitive to total pressure as well. The results of 27 wet experiments at 767-1160°C and 7-1000 MPa can be described a single Arrhenius relationship: D wet (m 2/s) = 5.5 × 10 -12exp(-25280/T) The insensitivity of oxygen diffusion to P H 2O means that applications to geologic problems can be pursued knowing only whether the system of interest was 'wet' (i.e., P H 2O > 7MPa ) or 'dry'. Under dry conditions (presumably rare in the crust), zircons are extremely retentive of their oxygen isotopic signatures, to the extent that δ 18O would be perturbed at the center of a 200 μm zircon only during an extraordinarily hot and protracted event (e.g., 65 Ma at 900°C). Under wet conditions, δ 18O may or may not be retained in the central regions of individual crystals, cores or overgrowth rims, depending upon the specific thermal history of the system.

Walking Wheel Design for Lunar Rove-Rand and Its Application Simulation Based on Virtual Lunar Environment

Directory of Open Access Journals (Sweden)

Zhao Yibing

2014-05-01

Full Text Available The lunar rover design is the key problem of planet exploration. It is extraordinarily important for researchers to fully understand the lunar terrain and propose the reasonable lunar rover. In this paper, one new type of walking wheel modeled on impeller is presented based on vehicle terramechanics. The passive earth pressure of soil mechanics put forward by C. A. Coulomb is employed to obtain the wheel traction force. Some kinematics simulations are conducted for lunar rover model. Besides, this paper presents how to model lunar landing terrain containing typical statistic characteristic including craters and boulders; then, the second step is to construct basal lunar surface by using Brown Fractal Motion and the next is to add craters and boulders by means of known diameter algorithm and Random-create Diameter Algorithm. By means of importing 2D plain of lunar surface into UG, 3D parasolid is modeled and finally imported to ADAMS, which is available for lunar rover kinematics and dynamics simulation. Lastly, based on power spectrum curve of lunar terrain, the spectral characteristic of three different lunar terrain roughness is educed by using reverse engineering algorithm. Simulation results demonstrated the frequency of vibration mechanics properties of different roughness surfaces.

Fabrication of zircon for disposition of weapons plutonium

International Nuclear Information System (INIS)

Kim, K.C.; Huang, J.Y.; Serrano, P.L.

1997-01-01

This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). In an effort to address the problems of long term storage and nuclear waste minimization, zircon has been proposed as a host medium for plutonium and other actinides recovered from dismantled nuclear weapons. The objective of this work is to investigate the feasibility of large scale fabrication of Pu-bearing zircon. Since PuO 2 is thermodynamically less stable than ZrO 2 , it is expected that the process parameters determined for synthesizing ZrSiO 4 (zircon) would be applicable to those for PuSiO 4 (Pu-zircon). Furthermore, since the foremost concern in plutonium processing is the potential for contamination release, this work emphasizes the development of process parameters, using zircon first, to anticipate potential material problems in the containment system for reaction mixtures during processing. Stoichiometric mixtures of ZrO 2 and SiO 2 , in hundred-gram batches, have been subjected to hot isostatic pressing (HIP) at temperatures near 1,500 C and pressures approximately 10,000 psi. The product materials have been analyzed by x-ray powder diffraction, and are found to consist of zircon after approximately two hours of reaction time. From this work, it is clear that the fabrication of large quantities of Pu-zircon is feasible. The most notable result of this work is evidence for the existence of container problems. This result, in turn, suggests potential solutions to these problems. Experiments with the quartz inner container, the glass sealant, a sacrificial metal barrier, and a metal outer container are being investigated to mitigate these potential hazards

Raman study of radiation-damaged zircon under hydrostatic compression

Science.gov (United States)

Nasdala, Lutz; Miletich, Ronald; Ruschel, Katja; Váczi, Tamás

2008-12-01

Pressure-induced changes of Raman band parameters of four natural, gem-quality zircon samples with different degrees of self-irradiation damage, and synthetic ZrSiO4 without radiation damage, have been studied under hydrostatic compression in a diamond anvil cell up to ~10 GPa. Radiation-damaged zircon shows similar up-shifts of internal SiO4 stretching modes at elevated pressures as non-damaged ZrSiO4. Only minor changes of band-widths were observed in all cases. This makes it possible to estimate the degree of radiation damage from the width of the ν3(SiO4) band of zircon inclusions in situ, almost independent from potential “fossilized pressures” or compressive strain acting on the inclusions. An application is the non-destructive analysis of gemstones such as corundum or spinel: broadened Raman bands are a reliable indicator of self-irradiation damage in zircon inclusions, whose presence allows one to exclude artificial color enhancement by high-temperature treatment of the specimen.

Comprehensive NASA Cis-Lunar Earth Moon Libration Orbit Reference and Web Application

Data.gov (United States)

National Aeronautics and Space Administration — This work will provide research and trajectory design analysis to develop a NASA Cis-Lunar / Earth-Moon Libration Orbit Reference and Web Application. A compendium...

Interplanetary and lunar surface SP-100 nuclear power applications

International Nuclear Information System (INIS)

Josloff, A.T.; Shepard, N.F.; Smith, M.; Stephen, J.D.

1992-01-01

This paper describes how the SP-100 Space Reactor Power System (SRPS) can be tailored to meet the specific requirements for a lunar surface power system to meet the needs of the consolidation and utilization phases outlined in the 90-day NASA SEI study report. This same basic power system can also be configured to obtain the low specific masses needed to enable robotic interplanetary science missions employing Nuclear Electric Propulsion (NEP). In both cases it is shown that the SP-100 SRPS can meet the specific requirements. For interplanetary NEP missions, performance upgrades currently being developed in the area of light weight radiators and improved thermoelectric material are assumed to be technology ready in the year 2000 time frame. For lunar applications, some system rearrangement and enclosure of critical components are necessary modifications to the present baseline design

Zircon-rutile-ilmenite froth flotation process

International Nuclear Information System (INIS)

Schmidt, R.; Denham, D.L. Jr.

1992-01-01

This patent describes a method for separating a mixture of minerals comprising at least zircon, ilmenite and rutile. It comprises adding an acid solution to the mixture to acidify to a pH of between about 2.0 and 6.0; adding starch to the mixture to depress the ilmenite and the rutile; adding a source of fluoride ions to the mixture to provide a negative surface charge on the zircon surface to activate the zircon; adding an amine cationic collector to the mixture to float the activated zircon; subjecting the mixture containing the added acid solution, the fluoride ions, the starch and the cationic collector, to froth flotation; and withdrawing a float product comprising the zircon and a sink product comprising the ilmenite and rutile

Application of energy-dispersive XRF technique in the hydrometallurgy study of local zircon

International Nuclear Information System (INIS)

Meor Yusoff Sulaiman; Kamaruddin Hussin; Azizan Aziz

1996-01-01

In this study, energy-dispersive X-ray Fluorescence (EDXR-F) was used to analyse the elemental composition of the starting zircon mineral associated elements in the leaching solution. Besides analysing the major elements i.e. of zirconium, silicon and hafnium, trace elemental analysis for iron, titanium and the naturally occurring radioactive element thorium and uranium are important in establishing the grades of Malaysian zircon. The technique was also used in determine the optimum conditions for zirconium and hafnium recovery during the leaching process

Mixture modeling of multi-component data sets with application to ion-probe zircon ages

Science.gov (United States)

Sambridge, M. S.; Compston, W.

1994-12-01

A method is presented for detecting multiple components in a population of analytical observations for zircon and other ages. The procedure uses an approach known as mixture modeling, in order to estimate the most likely ages, proportions and number of distinct components in a given data set. Particular attention is paid to estimating errors in the estimated ages and proportions. At each stage of the procedure several alternative numerical approaches are suggested, each having their own advantages in terms of efficency and accuracy. The methodology is tested on synthetic data sets simulating two or more mixed populations of zircon ages. In this case true ages and proportions of each population are known and compare well with the results of the new procedure. Two examples are presented of its use with sets of SHRIMP U-238 - Pb-206 zircon ages from Palaeozoic rocks. A published data set for altered zircons from bentonite at Meishucun, South China, previously treated as a single-component population after screening for gross alteration effects, can be resolved into two components by the new procedure and their ages, proportions and standard errors estimated. The older component, at 530 +/- 5 Ma (2 sigma), is our best current estimate for the age of the bentonite. Mixture modeling of a data set for unaltered zircons from a tonalite elsewhere defines the magmatic U-238 - Pb-206 age at high precision (2 sigma +/- 1.5 Ma), but one-quarter of the 41 analyses detect hidden and significantly older cores.

Lunar neutron source function

International Nuclear Information System (INIS)

Kornblum, J.J.

1974-01-01

The search for a quantitative neutron source function for the lunar surface region is justified because it contributes to our understanding of the history of the lunar surface and of nuclear process occurring on the moon since its formation. A knowledge of the neutron source function and neutron flux distribution is important for the interpretation of many experimental measurements. This dissertation uses the available pertinent experimental measurements together with theoretical calculations to obtain an estimate of the lunar neutron source function below 15 MeV. Based upon reasonable assumptions a lunar neutron source function having adjustable parameters is assumed for neutrons below 15 MeV. The lunar neutron source function is composed of several components resulting from the action of cosmic rays with lunar material. A comparison with previous neutron calculations is made and significant differences are discussed. Application of the results to the problem of lunar soil histories is examined using the statistical model for soil development proposed by Fireman. The conclusion is drawn that the moon is losing mass

ALKALI FUSION OF ROSETTA ZIRCON

International Nuclear Information System (INIS)

DAHER, A.

2008-01-01

The decomposition of Rosetta zircon by fusion with different types of alkalis has been investigated. These alkalis include sodium hydroxide, potassium hydroxide and eutectic mixture of both. The influences of the reaction temperature, zircon to alkalis ratio, fusion time and the stirring of the reactant on the fusion reaction have been evaluated. The obtained results favour the decomposition of zircon with the eutectic alkalis mixture by a decomposition efficiency of 96% obtained at 500 0 C after one hour

Wear and microstructural characteristics of spray atomized zircon sand reinforced LM13 alloy

Energy Technology Data Exchange (ETDEWEB)

Kaur, K.; Pandey, O.P. [School of Physics and Materials Science, Thapar University Patiala, Punjab (India)

2010-07-15

The requirement of the high performance light weight materials demands the development of varieties of materials within the economical range to get it commercialized. Light weight aluminium alloys are used in several structural applications like automotive, aerospace, defense industry and other fields of engineering. The ceramic particle reinforced aluminium metal matrix composites (AMCs) have emerged as a suitable candidate for commercial applications. A variety of processing routes have been adopted to manufacture AMCs. In the present work LM13 alloy reinforced with zircon sand is formed via spray forming. During experimentation a self prepared convergent-divergent nozzle is used for inert gas atomization of the melt which is subsequently deposited on copper substrate placed vertically below the atomizer. The zircon sand particles are injected in the atomization zone by external injectors aligned perpendicular to the gas atomization axis. Zircon sand has been found to have new promising economical commercial candidate due to its easy availability and good mechanical properties like high hardness, high modulus of elasticity and good thermal stability. The microhardness of cast alloy and spray formed composite shows that the spray formed zircon sand reinforced composite has higher hardness. Also the lower wear rate has been observed in case of the zircon sand reinforced AMC as compared to LM13 alloy. This behaviour is further analyzed in light of microstructural features of the spray deposited composite using optical and scanning electron microscope (SEM). A comparative study of this material (LM13/Zircon sand) with the parent alloy (LM13) is presented in this work. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

Sulfur in zircons: A new window into melt chemistry

Science.gov (United States)

Tang, H.; Bell, E. A.; Boehnke, P.; Barboni, M.; Harrison, T. M.

2017-12-01

The abundance and isotopic composition of sulfur are important tools for exploring the photochemistry of the atmosphere, the thermal history of mantle and igneous rocks, and ancient metabolic processes on the early Earth. Because the oldest terrestrial samples are zircons, we developed a new in-situ procedure to analyze the sulfur content of zircons using the CAMECA ims 1290 at UCLA. We analyzed zircons from three metaluminous/I-type granites (reduced and oxidized Peninsular range and Elba), which exhibit low sulfur abundance with the average of 0.5ppm, and one peraluminous/S-type zircon (Strathbogie Range), which shows an elevated sulfur level with the average of 1.5ppm. Additionally, we found that sulfur content ranges between 0.4 and 2.3 ppm in young volcanic zircons (St. Lucia). Our analyses of zircons from the Jack Hills, Western Australia, whose ages range between 3.4 and 4.1 Ga, show a variety of sulfur contents. Three out of the ten zircons are consistent with the sulfur contents of S-type zircons; the rest have low sulfur contents, which are similar to those of I-type zircons. The high sulfur content in some of these Jack Hills zircons can be interpreted as indicating their origin in either a S-type granite or a volcanic reservoir. We favor the former interpretation since the Ti-in-zircon temperatures of our Jack Hills zircons is lower than those of volcanic zircons. Future work will be undertaken to develop a systematic understanding of the relationship between melt volatile content, melt chemistry, and zircon sulfur content.

Lunar Regolith Particle Shape Analysis

Science.gov (United States)

Kiekhaefer, Rebecca; Hardy, Sandra; Rickman, Douglas; Edmunson, Jennifer

2013-01-01

Future engineering of structures and equipment on the lunar surface requires significant understanding of particle characteristics of the lunar regolith. Nearly all sediment characteristics are influenced by particle shape; therefore a method of quantifying particle shape is useful both in lunar and terrestrial applications. We have created a method to quantify particle shape, specifically for lunar regolith, using image processing. Photomicrographs of thin sections of lunar core material were obtained under reflected light. Three photomicrographs were analyzed using ImageJ and MATLAB. From the image analysis measurements for area, perimeter, Feret diameter, orthogonal Feret diameter, Heywood factor, aspect ratio, sieve diameter, and sieve number were recorded. Probability distribution functions were created from the measurements of Heywood factor and aspect ratio.

Inflight dissociation of zircon in air plasma

Energy Technology Data Exchange (ETDEWEB)

Yugeswaran, S; Selvarajan, V [Bharathiar University, Coimbatore 641046 (India); Ananthapadmanabhan, P V; Thiyagarajan, T K [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai - 400 085 (India); Nair, Janardhanan [Ion Arc Technologies Pvt Ltd, Coimbatore (India)

2010-02-01

Thermal dissociation of zircon can be conveniently carried out in a plasma reactor, which is characterized by high temperature, high energy density and high quench rate. Zirconia is recovered from this partially dissociated zircon by alkali leaching. Dissociation of zircon has been conventionally carried out in argon gas, which is expensive. The present paper reports experimental results on thermal dissociation of zircon in air plasma medium. Process simulation for 'inflight' dissociation of zircon in air plasma medium is also presented. The experimental system consists of a central hollow graphite electrode, which acts as the cathode and a graphite anode. The material to be processed is fed centrally through the cathode. The unique feature of the system is that it uses air as the working gas to generate the thermal plasma. The system has been used to study in-flight dissociation of zircon in the thermal plasma jet. Dissociation was carried out over 10-25 kW power range. Results of the study indicate that complete dissociation of zircon to ZrO{sub 2} and silica could be accomplished at 25 kW in air plasma.

Inflight dissociation of zircon in air plasma

International Nuclear Information System (INIS)

Yugeswaran, S; Selvarajan, V; Ananthapadmanabhan, P V; Thiyagarajan, T K; Nair, Janardhanan

2010-01-01

Thermal dissociation of zircon can be conveniently carried out in a plasma reactor, which is characterized by high temperature, high energy density and high quench rate. Zirconia is recovered from this partially dissociated zircon by alkali leaching. Dissociation of zircon has been conventionally carried out in argon gas, which is expensive. The present paper reports experimental results on thermal dissociation of zircon in air plasma medium. Process simulation for 'inflight' dissociation of zircon in air plasma medium is also presented. The experimental system consists of a central hollow graphite electrode, which acts as the cathode and a graphite anode. The material to be processed is fed centrally through the cathode. The unique feature of the system is that it uses air as the working gas to generate the thermal plasma. The system has been used to study in-flight dissociation of zircon in the thermal plasma jet. Dissociation was carried out over 10-25 kW power range. Results of the study indicate that complete dissociation of zircon to ZrO 2 and silica could be accomplished at 25 kW in air plasma.

At what conditions does zircon grow/dissolve during high-T metamorphism? Relating zircon textures to PT-conditions

Science.gov (United States)

Kunz, Barbara E.; Regis, Daniele; Manzotti, Paola; Engi, Martin

2015-04-01

A key question in ziconology is when and how zircon grows during metamorphism. To shed light on zircon forming processes and the corresponding PT-conditions during high-T metamorphism a case study was undertaken. The Ivrea Zone (N-Italy) exposes a lower continental crustal section in which a continuous metamorphic field gradient from amphibolite to granulite facies is documented. This field gradient is thought to reflect protracted heating during late Paleozoic times, with a probable high-T peak in the Permian. We present first results from a primarily textural study supported by U-Pb ages, Th/U ratios and Ti-in-Zrn thermometry. Four types of zircon were identified based on their overgrowth proportions and the preservation of detrital cores. Zircon grains were thus classified as Type1 - detrital grains with no overgrowth or very narrow rims (300 Ma) and appears to reflect an early dehydration phase. Rim2b has Permian ages (median 275 Ma), is by far the most common overgrowth type, found in a wide PT-range. Its development appears related to biotite breakdown. Rim3 is texturally indicative of magmatic zircon, occurs only in diatexites. Rim4 is the latest overgrowth and is locally found at all metamorphic grades. Textural features suggest late fluid-related recrystallization of existing zircon. At lowest grade (675±35°C, 6±2 kbar) zircons show type1 only, overgrowths are too thin to clearly identify the rim type. Further upgrade (~700°C, 7 kbar) type1 and type2 dominate. Type2 zircons show rim1, rim2a and occasionally rim4. At the Mu-out isograd (750±50°C, 8.2±1.4 kbar) most zircons are of type2, now with rim2b instead of 2a, in addition to rim1 and rim4. Near and in granulite facies (to 800°C, 8±2 kbar) mostly zircon type2 and type4 are present. While rim1 gets more narrow with increasing metamorphic grade, rim2b grows significantly thicker. Occasionally rim2a and rim4 occur. Close to the Bt-out isograd (~860°C, 9.2±1.7 kbar), mostly type3 and type4 are

Auto-regenerative thermoluminescence dating using zircon inclusions

International Nuclear Information System (INIS)

Templer, R.H.

1993-01-01

Fired ceramics containing zircon inclusions have been dated by allowing the zircons to regenerate their own thermoluminescence (TL) signal, hence auto-regenerative TL dating. The technique is conceptually straightforward. One first measures the TL accrued since the last heating of the material. The zircon grains are then stored for six months and the TL signal regenerated through self-irradiation is measured. Since the internal dose-rate for zircon is dominated by the internal component the age of the sample is simply given by the ratio of the natural to auto-regenerated signal times the laboratory storage period. The technique, however, requires the measurement of a very small auto-regenerated signal, which introduces a number of experimental and physical complications. The methods for overcoming these problems and successfully dating zircons by auto-regeneration are described. (Author)

Zircon-scale insights into the history of a Supervolcano, Bishop Tuff, Long Valley, California, with implications for the Ti-in-zircon geothermometer

Science.gov (United States)

Reid, M.R.; Vazquez, J.A.; Schmitt, A.K.

2011-01-01

Zircon has the outstanding capacity to record chronological, thermal, and chemical information, including the storage history of zoned silicic magma reservoirs like the one responsible for the Bishop Tuff of eastern California, USA. Our novel ion microprobe approach reveals that Bishop zircon rims with diverse chemical characteristics surround intermediate domains with broadly similar compositions. The highest Y, REE, U, and Th concentrations tend to accompany the largest excesses in Y + REE3+:P beyond what can be explained by xenotime substitution in zircon. Apparent Ti-in-zircon temperatures of Ti-in-zircon temperatures are probably better explained by sources of inaccuracy in the temperature estimates. After apparently nucleating from different melts, zircons from across the Bishop Tuff compositional spectrum may have evolved to broadly similar chemical and thermal conditions and therefore it is possible that there was no significant thermal gradient in the magma reservoir at some stage in its evolution. There is also no compelling evidence for punctuated heat ?? chemical influxes during the intermediate stages of zircon growth. Judging by the zircon record, the main volume of the erupted magma evolved normally by secular cooling but the latest erupted portion is characterized by a reversal in chemistry that appears to indicate perfusion of the magma reservoir by-or zircon entrainment in-a less evolved melt from the one in which the zircons had previously resided. ?? 2010 Springer-Verlag.

Transformations to granular zircon revealed: Twinning, reidite, and ZrO2 in shocked zircon from Meteor Crater (Arizona, USA)

Science.gov (United States)

Cavosie, Aaron; Timms, Nicholas E.; Erickson, Timmons M.; Hagerty, Justin J.; Hörz, Friedrich

2016-01-01

Granular zircon in impact environments has long been recognized but remains poorly understood due to lack of experimental data to identify mechanisms involved in its genesis. Meteor Crater in Arizona (United States) contains abundant evidence of shock metamorphism, including shocked quartz, the high pressure polymorphs coesite and stishovite, diaplectic SiO2 glass, and lechatelierite (fused SiO2). Here we report the presence of granular zircon, a new shocked mineral discovery at Meteor Crater, that preserve critical orientation evidence of specific transformations that occurred during its formation at extreme impact conditions. The zircon grains occur as aggregates of sub-µm neoblasts in highly shocked Coconino Formation Sandstone (CFS) comprised of lechatelierite. Electron backscatter diffraction shows that each grain consists of multiple domains, some with boundaries disoriented by 65°, a known {112} shock-twin orientation. Other domains have crystallographic c-axes in alignment with {110} of neighboring domains, consistent with the former presence of the high pressure ZrSiO4 polymorph reidite. Additionally, nearly all zircon preserve ZrO2 + SiO2, providing evidence of partial dissociation. The genesis of CFS granular zircon started with detrital zircon that experienced shock-twinning and reidite formation from 20 to 30 GPa, ultimately yielding a phase that retained crystallographic memory; this phase subsequently recrystallized to systematically oriented zircon neoblasts, and in some areas partially dissociated to ZrO2. The lechatelierite matrix, experimentally constrained to form at >2000 °C, provided an ultra high-temperature environment for zircon dissociation (~1670 °C) and neoblast formation. The capacity of granular zircon to preserve a cumulative P-T record has not been recognized previously, and provides a new method for retrieving histories of impact-related mineral transformations in the crust at conditions far beyond which most rocks melt.

NASA Lunar Base Wireless System Propagation Analysis

Science.gov (United States)

Hwu, Shian U.; Upanavage, Matthew; Sham, Catherine C.

2007-01-01

There have been many radio wave propagation studies using both experimental and theoretical techniques over the recent years. However, most of studies have been in support of commercial cellular phone wireless applications. The signal frequencies are mostly at the commercial cellular and Personal Communications Service bands. The antenna configurations are mostly one on a high tower and one near the ground to simulate communications between a cellular base station and a mobile unit. There are great interests in wireless communication and sensor systems for NASA lunar missions because of the emerging importance of establishing permanent lunar human exploration bases. Because of the specific lunar terrain geometries and RF frequencies of interest to the NASA missions, much of the published literature for the commercial cellular and PCS bands of 900 and 1800 MHz may not be directly applicable to the lunar base wireless system and environment. There are various communication and sensor configurations required to support all elements of a lunar base. For example, the communications between astronauts, between astronauts and the lunar vehicles, between lunar vehicles and satellites on the lunar orbits. There are also various wireless sensor systems among scientific, experimental sensors and data collection ground stations. This presentation illustrates the propagation analysis of the lunar wireless communication and sensor systems taking into account the three dimensional terrain multipath effects. It is observed that the propagation characteristics are significantly affected by the presence of the lunar terrain. The obtained results indicate the lunar surface material, terrain geometry and antenna location are the important factors affecting the propagation characteristics of the lunar wireless systems. The path loss can be much more severe than the free space propagation and is greatly affected by the antenna height, surface material and operating frequency. The

(De)coupled zircon metamictization, radiation damage, and He diffusivity

Science.gov (United States)

Ault, A. K.; Guenthner, W.; Reiners, P. W.; Moser, A. C.; Miller, G. H.; Refsnider, K. A.

2017-12-01

We develop and apply a new protocol for targeting crystals for the zircon (U-Th)/He (He) thermochronometry to maximize effective U (eU) and corresponding closure temperature variability to develop zircon He date-eU correlations observed in some datasets. Our approach exploits visual proxies for radiation damage accumulation (metamictization) during zircon selection. We show that by purposefully targeting a spectrum of zircon textures from pristine to metamict grains, it is possible to generate broad eU variation in suites of zircon from a single sample and zircon He date-eU-metamictization trends that can be exploited to resolve increasingly complex thermal histories. We present plane light photographs, eU concentration, and zircon He results from 59 individual zircons from nine crystalline rock samples. Six of the nine samples come from exposed Proterozoic granitoids on SE Baffin Island, Canada; Boulder Creek, CO; Sandia Mountains, NM; and Mecca Hills, CA. We report data from three Archean Baffin samples to compare with the Proterozoic Baffin sample date-eU-metamictization trend. In each Proterozoic sample, target zircons display a spectrum of metamictization from pristine, transparent crystals to purple-brown, translucent grains. Progressive loss of transparency and increase in discoloration consistently corresponds to an increase in eU in all samples. Individual zircon eU varies from 89-1885 ppm and, within each sample, the total eU spread is 538 ppm to 1374 ppm. For any given eU value, the Archean zircon appear comparatively more metamict than the Proterozoic Baffin grains and samples collectively define a 1681 ppm range in eU, with more restrictive intrasample eU spreads (199-1120 ppm). Proterozoic samples from Baffin, Sandia, and Front Range yield negative zircon He date-eU correlations with intrasample date ranges of 90-783 Ma. Increasing eU and younger dates correspond with increasing metamictization. In contrast, all three Proterozoic Mecca Hills samples

Role of zircon in tracing crustal growth and recycling

Science.gov (United States)

Compston, W.; Williams, I. S.; Armstrong, R. A.; Claoue-Long, J. C.; Kinny, P. D.; Foster, J. J.; Kroener, A.; Pidgeon, R. T.; Myers, J. S.

Single crystal ion probe ages of zircons is discussed, which allow much better time resolution compared to other geochronological methods, although the technique is not without problems. Rocks from two areas that contain composite zircon populations, including true magmatic zircons as well as a variety of xenocrystic types are described. It is often difficult to distinguish these; xenocrystic zircons, for example, cannot always be identified on the basis of morphology alone. Additional evidence is needed before making age interpretations. Evidence is also presented of zircon growth long after the original time of crystallization, in some cases apparently at temperatures less than 300 C. The spectacular discovery of 4.1 to 4.2 Ga detrital zircons in metaquartzites from the Mount Narryer area of Western Australia is described. Similar zircons with ages as old as 4276 Ma have been found in the nearby Jack Hills area. The source areas or parent lithologies of these zircons have not yet been determined, but the author expects that they may be unrecognized or buried antecedents of the K rich Narryer gneisses. U or Th concentrations of zircon cannot be used to discriminate between felsic and mafic source rocks.

Beneficiation of low grade zircon concentrate

International Nuclear Information System (INIS)

Rehim, A.A.

1976-01-01

The zircon concentrate obtained from black sands, contains considerable amount of rutile and some ilmenite. It is necessary to separate these minerals before the metallurgical processing of zircon, as otherwise the zirconium products obtained will be contaminated with large amount of titanium. The present work explores the possibility of purification of zircon from rutile and other minerals by flotation. Effective separation can be obtained by selective flotation using oleic acid and liquid glass in alkaline medium or sodium silicon fluoride in weak acidic medium. (author)

Zircon/fluid trace element partition coefficients measured by recrystallization of Mud Tank zircon at 1.5 GPa and 800-1000 °C

Science.gov (United States)

Ayers, John C.; Peters, Timothy J.

2018-02-01

Hydrothermal zircon grains have trace element characteristics such as low Th/U, high U, and high rare earth element (REE) concentrations that distinguish them from magmatic, metamorphic, and altered zircon grains, but it is unclear whether these characteristics result from distinctive fluid compositions or zircon/fluid fractionation effects. New experiments aimed at measuring zircon/fluid trace element partition coefficients Dz/f involved recrystallizing natural Mud Tank zircon with low trace element concentrations in the presence of H2O, 1 m NaOH, or 1 m HCl doped with ∼1000 ppm of rare earth elements (REE), Y, U and Th and ∼500 ppm of Li, B, P, Nb, Ba, Hf, and Ta. Experiments were run for 168 h at 1.5 GPa, 800-1000 °C, and fO2 = NNO in a piston cylinder apparatus using the double capsule method. LA-ICP-MS analysis shows that run product zircon crystals have much higher trace element concentrations than in Mud Tank zircon starting material. Dz/f values were estimated from run product zircon analyses and bulk composition using mass balance. Most elements behave incompatibly, with median Dz/f being highest for Hf = 8 and lowest for B = 0.02. Addition of NaOH or HCl had little influence on Dz/f values. Dz/f for LREE are anomalously high, likely due to contamination of run product zircon with quenched solutes enriched in incompatible elements, so DLREE were estimated using lattice strain theory. Brice curves for +3 ions yield zircon/fluid DLu/DLa of ∼800-5000. A Brice curve fit to +4 ions yielded DCe4+ values. Estimated concentrations of Ce3+ and Ce4+ show that the average Ce4+/Ce3+ in zircon of 27 is much higher than in fluid of 0.02. Th and U show little fractionation, with median DTh/DU = 0.7, indicating that the low Th/U in natural hydrothermal zircon is inherited from the fluid. Natural fluid compositions estimated from measured Dz/f and published compositions of hydrothermal zircon grains from aplite and eclogite reflect the mineralogy of the host rock, e

Low-Energy Ballistic Transfers to Lunar Halo Orbits

Science.gov (United States)

Parker, Jeffrey S.

2009-01-01

Recent lunar missions have begun to take advantage of the benefits of low-energy ballistic transfers between the Earth and the Moon rather than implementing conventional Hohmann-like lunar transfers. Both Artemis and GRAIL plan to implement low-energy lunar transfers in the next few years. This paper explores the characteristics and potential applications of many different families of low-energy ballistic lunar transfers. The transfers presented here begin from a wide variety of different orbits at the Earth and follow several different distinct pathways to the Moon. This paper characterizes these pathways to identify desirable low-energy lunar transfers for future lunar missions.

Fission track dating of zircon: a multichronometer

International Nuclear Information System (INIS)

Carpena, J.

1992-01-01

Scattering in Fission Track ages of zircons of a single rock is possible when they present morphological and geochemical variations, if the greatest care is not taken in the choice of the etching conditions and the counting of tracks. The Fission Track study of two heterogeneous populations of zircons from the Mont Blanc granite and from the Gran Paradiso gneisses allows to show that zircon may work as a multichronometer

Single-zircon dating by stepwise Pb-evaporation constrains the Archean history of detrital zircons from the Jack Hills, Western Australia

International Nuclear Information System (INIS)

Kober, B.; Lippolt, H.J.; Pidgeon, R.T.

1989-01-01

Pb isotope analyses have been carried out on 42 zircon grains from a Western Australian metaconglomerate using stepwise Pb-evaporation directly in the ion source of a thermal ionization mass spectrometer. The metaconglomerate is from the Archean Jack Hills Metasedimentary Belt, and is known from ion microprobe (''SHRIMP'') analyses to contain a complex zircon population with ages between 4.2 Ga and 3.1 Ga. The same complex pattern of ages is found by the Pb evaporation studies. Five grains yielded minimum crystallization ages from 4.17 Ga to 4.07 Ga. The main population appears significantly younger, having been generated at about 3.55-3.3 Ga. The agreement between the two analytical approaches confirms the SHRIMP results and demonstrates the value of the stepwise-evaporation technique in determining the age patterns of mixing zircon populations. In many of the evaporative Pb isotope records the 207/206 ratios remained constant for all evaporation steps, which we interpret as evaporation from concordant zircon phases. However, for the majority of zircons 207/206 ratios increased with increasing evaporation temperature, and usually approached constant values during evaporation at the highest temperatures. This can be attributed to mixing of different radiogenic Pb components from either crystalline zircon phases of different ages or from domains of isotopically disturbed metamict zircon. Present results confirm > 4 Ga zircon ages in the metaconglomerate from the Hack Hills and substantiate formation of crust at a very early stage in the evolution of the earth. Results also confirm a major crust-forming event 3.55-3.3 Ga ago. (orig.)

Laser Ablation in situ (U-Th-Sm)/He and U-Pb Double-Dating of Apatite and Zircon: Techniques and Applications

Science.gov (United States)

McInnes, B.; Danišík, M.; Evans, N.; McDonald, B.; Becker, T.; Vermeesch, P.

2015-12-01

We present a new laser-based technique for rapid, quantitative and automated in situ microanalysis of U, Th, Sm, Pb and He for applications in geochronology, thermochronometry and geochemistry (Evans et al., 2015). This novel capability permits a detailed interrogation of the time-temperature history of rocks containing apatite, zircon and other accessory phases by providing both (U-Th-Sm)/He and U-Pb ages (+trace element analysis) on single crystals. In situ laser microanalysis offers several advantages over conventional bulk crystal methods in terms of safety, cost, productivity and spatial resolution. We developed and integrated a suite of analytical instruments including a 193 nm ArF excimer laser system (RESOlution M-50A-LR), a quadrupole ICP-MS (Agilent 7700s), an Alphachron helium mass spectrometry system and swappable flow-through and ultra-high vacuum analytical chambers. The analytical protocols include the following steps: mounting/polishing in PFA Teflon using methods similar to those adopted for fission track etching; laser He extraction and analysis using a 2 s ablation at 5 Hz and 2-3 J/cm2fluence; He pit volume measurement using atomic force microscopy, and U-Th-Sm-Pb (plus optional trace element) analysis using traditional laser ablation methods. The major analytical challenges for apatite include the low U, Th and He contents relative to zircon and the elevated common Pb content. On the other hand, apatite typically has less extreme and less complex zoning of parent isotopes (primarily U and Th). A freeware application has been developed for determining (U-Th-Sm)/He ages from the raw analytical data and Iolite software was used for U-Pb age and trace element determination. In situ double-dating has successfully replicated conventional U-Pb and (U-Th)/He age variations in xenocrystic zircon from the diamondiferous Ellendale lamproite pipe, Western Australia and increased zircon analytical throughput by a factor of 50 over conventional methods

Fission track dating of kimberlitic zircons

International Nuclear Information System (INIS)

Haggerty, S.E.

1983-01-01

The only reliable method for dating kimberlites at present is the lengthy and specialized hydrothermal procedure that extracts 206 Pb and 238 U from low-uranium zircons. This paper describes a second successful method by fission track dating of large single-crystal zircons, 1.0-1.5 cm in dimension. The use of large crystals overcomes the limitations imposed in conventional fission track analysis which utilizes crushed fragments. Low track densities, optical track dispersion, and the random orientation of polished surfaces in the etch and irradiation cycle are effectively overcome. Fission track ages of zircons from five African kimberlites are reported, from the Kimberley Pool (90.0 +- 6.5 m.y.), Orapa (87.4 +- 5.7 and 92.4 +- 6.1 m.y.), Nzega (51.1 +- 3.8 m.y.), Koffiefontein (90.9 +- 8.2 m.y.), and Val do Queve (133.4 +- 11.5 m.y.). In addition we report the first radiometric ages (707.9 +- 59.6 and 705.5 +- 61.0 m.y.) of crustal zircons from kimberlites in northwest Liberia. The fission track ages agree well with earlier age estimates. Most of the zircons examined in this study are zoned with respect to uranium but linear correlations are established (by regression analysis) between zones of variable uranium content, and within zones of constant uranium content (by analysis of variance). Concordance between the fission track method and the U/Pb technique is established and we concluded that track fading from thermal annealing has not taken place. Kimberlitic zircons dated in this study, therefore, record the time of eruption. (orig.)

Testing the reliability of information extracted from ancient zircon

Science.gov (United States)

Kielman, Ross; Whitehouse, Martin; Nemchin, Alexander

2015-04-01

Studies combining zircon U-Pb chronology, trace element distribution as well as O and Hf isotope systematics are a powerful way to gain understanding of the processes shaping Earth's evolution, especially in detrital populations where constraints from the original host are missing. Such studies of the Hadean detrital zircon population abundant in sedimentary rocks in Western Australia have involved analysis of an unusually large number of individual grains, but also highlighted potential problems with the approach, only apparent when multiple analyses are obtained from individual grains. A common feature of the Hadean as well as many early Archaean zircon populations is their apparent inhomogeneity, which reduces confidence in conclusions based on studies combining chemistry and isotopic characteristics of zircon. In order to test the reliability of information extracted from early Earth zircon, we report results from one of the first in-depth multi-method study of zircon from a relatively simple early Archean magmatic rock, used as an analogue to ancient detrital zircon. The approach involves making multiple SIMS analyses in individual grains in order to be comparable to the most advanced studies of detrital zircon populations. The investigated sample is a relatively undeformed, non-migmatitic ca. 3.8 Ga tonalite collected a few kms south of the Isua Greenstone Belt, southwest Greenland. Extracted zircon grains can be combined into three different groups based on the behavior of their U-Pb systems: (i) grains that show internally consistent and concordant ages and define an average age of 3805±15 Ma, taken to be the age of the rock, (ii) grains that are distributed close to the concordia line, but with significant variability between multiple analyses, suggesting an ancient Pb loss and (iii) grains that have multiple analyses distributed along a discordia pointing towards a zero intercept, indicating geologically recent Pb-loss. This overall behavior has

2007 Lunar Regolith Simulant Workshop Overview

Science.gov (United States)

McLemore, Carole A.; Fikes, John C.; Howell, Joe T.

2007-01-01

The National Aeronautics and Space Administration (NASA) vision has as a cornerstone, the establishment of an Outpost on the Moon. This Lunar Outpost will eventually provide the necessary planning, technology development, and training for a manned mission to Mars in the future. As part of the overall activity, NASA is conducting Earth-based research and advancing technologies to a Technology Readiness Level (TRL) 6 maturity under the Exploration Technology Development Program that will be incorporated into the Constellation Project as well as other projects. All aspects of the Lunar environment, including the Lunar regolith and its properties, are important in understanding the long-term impacts to hardware, scientific instruments, and humans prior to returning to the Moon and living on the Moon. With the goal of reducing risk to humans and hardware and increasing mission success on the Lunar surface, it is vital that terrestrial investigations including both development and verification testing have access to Lunar-like environments. The Marshall Space Flight Center (MSFC) is supporting this endeavor by developing, characterizing, and producing Lunar simulants in addition to analyzing existing simulants for appropriate applications. A Lunar Regolith Simulant Workshop was conducted by MSFC in Huntsville, Alabama, in October 2007. The purpose of the Workshop was to bring together simulant developers, simulant users, and program and project managers from ETDP and Constellation with the goals of understanding users' simulant needs and their applications. A status of current simulant developments such as the JSC-1A (Mare Type Simulant) and the NASA/U.S. Geological Survey Lunar Highlands-Type Pilot Simulant (NU-LHT-1 M) was provided. The method for evaluating simulants, performed via Figures of Merit (FoMs) algorithms, was presented and a demonstration was provided. The four FoM properties currently being assessed are: size, shape, density, and composition. Some of the

A comparison of two systems for lunar surface remote and mobile power applications

International Nuclear Information System (INIS)

Determan, W.R.; Otting, W.D.; Hunt, M.E.

1993-01-01

The free piston Stirling engine (FPSE) is now being developed by Mechanical Technology Incorporated (MTI) and NASA-LeRC for space power applications. Some conceptualizations of an isotope powered FPSE have been proposed. The performance characteristics of the proposed 2.5-kWe Stirling Isotope Power (STIP) system were developed for lunar surface remote and mobile applications. The Stirling system configuration uses a nonredundant power conversion system coupled to an annular heat source assembly (HSA) using an array of sodium heat pipes which transfer energy from the annular general-purpose heat source (GPHS) stack within the HSA to the Stirling heater head. The Stirling engine uses a dual-opposed piston design with heater head coupling. The engine coolers are connected to a single-pumped coolant loop, which rejects the cycle's waste heat to a radiator. Quantitative information, such as mass, area, and efficiency, are reported for the system. The results of a qualitative evaluation of the proposed STIP system against the desirable attributes of a lunar-based isotope power system are presented. Alternate configurations are also presented

Are there impact-formed zircons in the Hadean record?

Science.gov (United States)

Wielicki, M. M.; Lu, X.; Bell, E. A.; Schmitt, A. K.; Harrison, T. M.

2008-12-01

Detrital Hadean zircons from the Jack Hills, Western Australia, show a remarkable cluster of crystallization temperatures at 680±25°C. This is particularly surprising as a simple model relating rock composition and Zr concentration predicts that a very broad spectrum of crystallization temperatures (ca. 650°C to 1000°C) with a median value of 780°C, would result from impact melting of the Earth's surface. Magmatic fractionation would tend to increase the aforementioned values. Given the predicted high rate of impacts during the Hadean, the absence of such a population in the Jack Hills zircons could signal a profound sampling problem, a hint of a history much different than previously supposed, or our lack of understanding of zircon formation due to impact related processes. We have begun to examine the latter issue by investigating the crystallization temperatures of zircons formed in melt sheets preserved in the geologic record. The Sudbury Igneous Complex, formed at 1850±3 Ma within the second largest impact crater on Earth, includes two igneous units termed the Black and Felsic Norites. Examination of zircons from each by SIMS confirms their crystallization age at 1847.3±2.2 Ma and yields Ti-in-zircon temperatures of 720°C and 750°C, respectively. This is consistent with that predicted from zircon saturation systematics. A statistical test indicates that the combined norite population is distinct from the Hadean temperature distribution. Thus the question arises: where are the Hadean zircons expected to have formed at >780°C via impact processes? Similar analysis is being pursued for zircons from the Vredefort Impact Structure, South Africa, which should provide further information on impact-formed zircon temperature spectra.

Lunar power systems. Final report

International Nuclear Information System (INIS)

1986-12-01

The findings of a study on the feasibility of several methods of providing electrical power for a permanently manned lunar base are provided. Two fundamentally different methods for lunar electrical power generation are considered. One is the use of a small nuclear reactor and the other is the conversion of solar energy to electricity. The baseline goal was to initially provide 300 kW of power with growth capability to one megawatt and eventually to 10 megawatts. A detailed, day by day scenario for the establishment, build-up, and operational activity of the lunar base is presented. Also presented is a conceptual approach to a supporting transportation system which identifies the number, type, and deployment of transportation vehicles required to support the base. An approach to the use of solar cells in the lunar environment was developed. There are a number of heat engines which are applicable to solar/electric conversions, and these are examined. Several approaches to energy storage which were used by the electric power utilities were examined and those which could be used at a lunar base were identified

Lunar Wireless Power Transfer Feasibility Study

Energy Technology Data Exchange (ETDEWEB)

Freid, Sheldon [National Security Technologies, LLC. (NSTec), Mercury, NV (United States); Popovic, Zoya [Univ. of Colorado, Boulder, CO (United States); Beckett, David R. [Independent Consultant; Anderson, Scott R. [Independent Consultant; Mann, Diana [Independent Consultant; Walker, Stuart [Independent Consultant

2008-03-01

This study examines the feasibility of a multi-kilowatt wireless radio frequency (RF) power system to transfer power between lunar base facilities. Initial analyses, show that wireless power transfer (WPT) systems can be more efficient and less expensive than traditional wired approaches for certain lunar and terrestrial applications. The study includes evaluations of the fundamental limitations of lunar WPT systems, the interrelationships of possible operational parameters, and a baseline design approach for a notionial system that could be used in the near future to power remote facilities at a lunar base. Our notional system includes state-of-the-art photovoltaics (PVs), high-efficiency microwave transmitters, low-mass large-aperture high-power transmit antennas, high-efficiency large-area rectenna receiving arrays, and reconfigurable DC combining circuitry.

Morphology versus U-Pb systematics in zircon: A high-resolution isotopic study of a zircon population from a Variscan dike in the Central Alps

International Nuclear Information System (INIS)

Bossart, P.J.; Meier, M.; Oberli, F.; Steiger, R.H.

1986-01-01

U/Pb isotopic measurements on individual zircon crystals combined with morphological analyses permit the identification of three distinct components within the zircon population of the Saedelhorn diorite, a Variscan dike from the western Gotthard (Central Alps, Switzerland): (i) 94% of the grains in the zircon population are elongate crystals with pronounced skeletal morphology indicative of rapid growth from a supercooled melt. (ii) 5% of the population consist of turbid, mostly subhedral zircons frequently showing D-type morphology and elevated uranium contents compared to the skeletal variety. Single-crystal and multi-grain U-Pb isotopic data of group (i) and (ii) zircons define an intrusion age of 293 + 5/ -4 m.y. for the dike. (iii) Rare, transparent zircon crystals (< 1% of the zircons population) yield apparent U-Pb ages in the range of 370-490 m.y. and display morphological and isotopic characteristics closely resembling those of a Caledonian orthogneiss intruded by the dike. This implies presence of assimilated wall-rock components in the macroscopically homogeneous dike sample. (orig./WB)

Preparation and properties of calcium zirconate

International Nuclear Information System (INIS)

Dudek, M.; Bucko, M.; Rog, G.

2001-01-01

Dense samples of calcium zirconate were prepared. Electrical conductivity of the samples were measured in the temperature range 873 - 1273 K by both the d.c. four probe and the impedance spectroscopy methods. Calcium zirconate with small excess of calcium oxide appeared to be oxygen ion conductor. It was applied as an electrolyte in solid-state galvanic cells. (author)

Lunar landing and launch facilities and operations

Science.gov (United States)

1988-01-01

A preliminary design of a lunar landing and launch facility for a Phase 3 lunar base is formulated. A single multipurpose vehicle for the lunar module is assumed. Three traffic levels are envisioned: 6, 12, and 24 landings/launches per year. The facility is broken down into nine major design items. A conceptual description of each of these items is included. Preliminary sizes, capacities, and/or other relevant design data for some of these items are obtained. A quonset hut tent-like structure constructed of aluminum rods and aluminized mylar panels is proposed. This structure is used to provide a constant thermal environment for the lunar modules. A structural design and thermal analysis is presented. Two independent designs for a bridge crane to unload/load heavy cargo from the lunar module are included. Preliminary investigations into cryogenic propellant storage and handling, landing/launch guidance and control, and lunar module maintenance requirements are performed. Also, an initial study into advanced concepts for application to Phase 4 or 5 lunar bases has been completed in a report on capturing, condensing, and recycling the exhaust plume from a lunar launch.

Characterizing the Lunar Particulate Atmosphere with the Autonomous Lunar Dust Observer (ALDO)

Science.gov (United States)

Grund, C. J.; Colwell, J. A.

2008-07-01

Photoelectric effects and solar wind charge the lunar surface, levitating particles. ALDO maps suspended dust in 3D using lidar. Phenomenology and instrument modeling, applications, projected performance and concepts of operation are discussed.

Carbon Dioxide Adsorption by Calcium Zirconate at Higher Temperature

Directory of Open Access Journals (Sweden)

K. B. Kale

2012-12-01

Full Text Available The CO2 adsorption by calcium zirconate was explored at pre- and post- combustion temperature condition. The several samples of the calcium zirconate were prepared by different methods such as sol-gel, solid-solid fusion, template and micro-emulsion. The samples of the calcium zirconate were characterized by measurement of surface area, alkalinity/acidity, and recording the XRD patterns and SEM images. The CO2 adsorptions by samples of the calcium zirconate were studied in the temperature range 100 to 850 oC and the CO2 adsorptions were observed in the ranges of 6.88 to 40.6 wt % at 600 0C and 8 to 16.82 wt% at in between the temperatures 200 to 300 oC. The effect of Ca/Zr mol ratio in the samples of the calcium zirconate on the CO2 adsorption and alkalinity were discussed. The adsorbed moisture by the samples of the calcium zirconate was found to be useful for the CO2 adsorption. The promoted the samples of the calcium zirconate by K+, Na+, Rb+, Cs+, Ag+ and La3+ showed the increased CO2 adsorption. The exposure time of CO2 on the samples of the calcium zirconate showed the increased CO2 adsorption. The samples of the calcium zirconate were found to be regenerable and reusable several times for the adsorption of CO2 for at the post- and pre-combustion temperature condition. Copyright © 2012 by BCREC Undip. All rights reservedReceived: 23rd June 2012, Revised: 28th August 2012, Accepted: 30th August 2012[How to Cite: K. B. Kale, R. Y. Raskar, V. H. Rane and A. G.  Gaikwad (2012. Carbon Dioxide Adsorption by Calcium Zirconate at Higher Temperature. Bulletin of Chemical Reaction Engineering & Catalysis, 7 (2: 124-136. doi:10.9767/bcrec.7.2.3686.124-136] [How to Link / DOI: http://dx.doi.org/10.9767/bcrec.7.2.3686.124-136 ] | View in 

Lunar-derived titanium alloys for hydrogen storage

Science.gov (United States)

Love, S.; Hertzberg, A.; Woodcock, G.

1992-01-01

Hydrogen gas, which plays an important role in many projected lunar power systems and industrial processes, can be stored in metallic titanium and in certain titanium alloys as an interstitial hydride compound. Storing and retrieving hydrogen with titanium-iron alloy requires substantially less energy investment than storage by liquefaction. Metal hydride storage systems can be designed to operate at a wide range of temperatures and pressures. A few such systems have been developed for terrestrial applications. A drawback of metal hydride storage for lunar applications is the system's large mass per mole of hydrogen stored, which rules out transporting it from earth. The transportation problem can be solved by using native lunar materials, which are rich in titanium and iron.

Gold in Accessory Zircon (the Kozhim Massif, Subpolar Urals)

Science.gov (United States)

Denisova, Yuliya; Pystin, Aleksandr

2017-12-01

The crystals of zircon due to their resistance to external impact of various processes can reveal information about the environment of their formation and the inclusions observed of them. Zircon contains different mineral inclusions: biotite, plagioclase, quartz, apatite, etc. However, there is no information about gold inclusions in the zircons from granites of the Sudpolar Urals. The study results of the inclusions of gold in accessory zircon of the Kozhim granitic massif are presented in this paper. The studied mineral is a dark-brown translucent short-prismatic crystal containing the inclusion of gold and the allocations of quartz. According to studies, the inclusion of gold formed during the growth of zircon and it is the gold covered with a thin film of oxide gold. It was confirmed that the crystallization of the studied zircon occurred at a temperature of 800°C and above on the stage of formation of granites of Kozhim massif. The assumption is made about the additional temperature in the course of which was caused by decreasing of temperature up to 700° C and below during postmagmatic stage.

Chemical abrasion-SIMS (CA-SIMS) U-Pb dating of zircon from the late Eocene Caetano caldera, Nevada

Science.gov (United States)

Watts, Kathryn E.; Coble, Matthew A.; Vazquez, Jorge A.; Henry, Christopher D.; Colgan, Joseph P.; John, David A.

2016-01-01

Zircon geochronology is a critical tool for establishing geologic ages and time scales of processes in the Earth's crust. However, for zircons compromised by open system behavior, achieving robust dates can be difficult. Chemical abrasion (CA) is a routine step prior to thermal ionization mass spectrometry (TIMS) dating of zircon to remove radiation-damaged parts of grains that may have experienced open system behavior and loss of radiogenic Pb. While this technique has been shown to improve the accuracy and precision of TIMS dating, its application to high-spatial resolution dating methods, such as secondary ion mass spectrometry (SIMS), is relatively uncommon. In our efforts to U-Pb date zircons from the late Eocene Caetano caldera by SIMS (SHRIMP-RG: sensitive high resolution ion microprobe, reverse geometry), some grains yielded anomalously young U-Pb ages that implicated Pb-loss and motivated us to investigate with a comparative CA and non-CA dating study. We present CA and non-CA 206Pb/238U ages and trace elements determined by SHRIMP-RG for zircons from three Caetano samples (Caetano Tuff, Redrock Canyon porphyry, and a silicic ring-fracture intrusion) and for R33 and TEMORA-2 reference zircons. We find that non-CA Caetano zircons have weighted mean or bimodal U-Pb ages that are 2–4% younger than CA zircons for the same samples. CA Caetano zircons have mean U-Pb ages that are 0.4–0.6 Myr older than the 40Ar/39Ar sanidine eruption age (34.00 ± 0.03 Ma; error-weighted mean, 2σ), whereas non-CA zircons have ages that are 0.7–1.3 Myr younger. U-Pb ages do not correlate with U (~ 100–800 ppm), Th (~ 50–300 ppm) or any other measured zircon trace elements (Y, Hf, REE), and CA and non-CA Caetano zircons define identical trace element ranges. No statistically significant difference in U-Pb age is observed for CA versus non-CA R33 or TEMORA-2 zircons. Optical profiler measurements of ion microprobe pits demonstrate consistent depths of ~ 1.6�

Multivariate statistical analysis - an application to lunar materials

International Nuclear Information System (INIS)

Deb, M.

1978-01-01

The compositional characteristics of clinopyroxenes and spinels - two minerals considered to be very useful in deciphering lunar history, have been studied using the multivariate statistical method of principal component analysis. The mineral-chemical data used are from certain lunar rocks and fines collected by Apollo 11, 12, 14 and 15 and Luna 16 and 20 missions, representing mainly the mare basalts and also non-mare basalts, breccia and rock fragments from the highland regions, in which a large number of these minerals have been analyzed. The correlations noted in the mineral compositions, indicating substitutional relationships, have been interpreted on the basis of available crystal-chemical and petrological informations. Compositional trends for individual specimens have been delineated and compared by producing ''principal latent vector diagrams''. The percent variance of the principal components denoted by the eigenvalues, have been evaluated in terms of the crystallization history of the samples. Some of the major petrogenetic implications of this study concern the role of early formed cumulate phases in the near-surface fractionation of mare basalts, mixing of mineral compositions in the highland regolith and the subsolidus reduction trends in lunar spinels. (auth.)

Silica-calcium zirconate nanocomposite, studying its thermal

Indian Academy of Sciences (India)

Silica–calcium zirconate nanocomposite was prepared in a two-step procedure. First, nanocalcium zirconate was synthesized by the modified sol–gel method; then, silica was added to the prepared sol and the resulting product was calcined at 700–1000° C. Dilatometric measurements were performed to determine the ...

Does application of the Rosiwal principle to lunar soils require that concentrations of solar-wind-implanted species be grain-size independent

International Nuclear Information System (INIS)

Becker, R.H.

1977-01-01

A reconsideration of the application of the Rosiwal Principle to lunar soils indicates a flaw in arguments put forth previously by Criswell. Specifically, by introducing a boundary condition which must exist at the lunar surface, it is shown that concentrations of solar-wind-implanted species showing a dependence on grain size may be able to develop in soils at concentration levels below those required for saturation of grain surfaces. As a result, observed grain-size-dependent concentrations of solar-wind species in lunar soils do not necessarily require the exposure time scales or solar-wind fluxes deduced from the arguments of Criswell. (Auth.)

Mid-1970's imbalance in zircon supply and demand

International Nuclear Information System (INIS)

Van Gordon, D.V.; Collins, R.E.

1975-01-01

Mining and the historical development of the zircon market are briefly reviewed. Causes of the fluctuations in the zircon demand and supply and in the price are discussed. Possible adjustments (such as substitution of other materials in the steel foundry) are listed. Future uses of zircon will probably be limited to those which can justify high prices and those for which there are no substitutes. (DLC)

Lithofacies control in detrital zircon provenance studies: Insights from the Cretaceous Methow basin, southern Canadian Cordillera

Science.gov (United States)

DeGraaff-Surpless, K.; Mahoney, J.B.; Wooden, J.L.; McWilliams, M.O.

2003-01-01

High-frequency sampling for detrital zircon analysis can provide a detailed record of fine-scale basin evolution by revealing the temporal and spatial variability of detrital zircon ages within clastic sedimentary successions. This investigation employed detailed sampling of two sedimentary successions in the Methow/Methow-Tyaughton basin of the southern Canadian Cordillera to characterize the heterogeneity of detrital zircon signatures within single lithofacies and assess the applicability of detrital zircon analysis in distinguishing fine-scale provenance changes not apparent in lithologic analysis of the strata. The Methow/Methow-Tyaughton basin contains two distinct stratigraphic sequences of middle Albian to Santonian clastic sedimentary rocks: submarine-fan deposits of the Harts Pass Formation/Jackass Mountain Group and fluvial deposits of the Winthrop Formation. Although both stratigraphic sequences displayed consistent ranges in detrital zircon ages on a broad scale, detailed sampling within each succession revealed heterogeneity in the detrital zircon age distributions that was systematic and predictable in the turbidite succession but unpredictable in the fluvial succession. These results suggest that a high-density sampling approach permits interpretation of finescale changes within a lithologically uniform turbiditic sedimentary succession, but heterogeneity within fluvial systems may be too large and unpredictable to permit accurate fine-scale characterization of the evolution of source regions. The robust composite detrital zircon age signature developed for these two successions permits comparison of the Methow/Methow-Tyaughton basin age signature with known plutonic source-rock ages from major plutonic belts throughout the Cretaceous North American margin. The Methow/Methow-Tyaughton basin detrital zircon age signature matches best with source regions in the southern Canadian Cordillera, requiring that the basin developed in close proximity to the

Response of zircon to melting and metamorphism in deep arc crust, Fiordland (New Zealand): implications for zircon inheritance in cordilleran granites

Science.gov (United States)

Bhattacharya, Shrema; Kemp, A. I. S.; Collins, W. J.

2018-04-01

The Cretaceous Mount Daniel Complex (MDC) in northern Fiordland, New Zealand was emplaced as a 50 m-thick dyke and sheet complex into an active shear zone at the base of a Cordilleran magmatic arc. It was emplaced below the 20-25 km-thick, 125.3 ± 1.3 Ma old Western Fiordland Orthogneiss (WFO) and is characterized by metre-scale sheets of sodic, low and high Sr/Y diorites and granites. 119.3 ± 1.2 Ma old, pre-MDC lattice dykes and 117.4 ± 3.1 Ma late-MDC lattice dykes constrain the age of the MDC itself. Most dykes were isoclinally folded as they intruded, but crystallised within this deep-crustal, magma-transfer zone as the terrain cooled and was buried from 25 to 50 km (9-14 kbar), based on published P-T estimated from the surrounding country rocks. Zircon grains formed under these magmatic/granulite facies metamorphic conditions were initially characterized by conservatively assigning zircons with oscillatory zoning as igneous and featureless rims as metamorphic, representing 54% of the analysed grains. Further petrological assignment involved additional parameters such as age, morphology, Th/U ratios, REE patterns and Ti-in-zircon temperature estimates. Using this integrative approach, assignment of analysed grains to metamorphic or igneous groupings improved to 98%. A striking feature of the MDC is that only 2% of all igneous zircon grains reflect emplacement, so that the zircon cargo was almost entirely inherited, even in dioritic magmas. Metamorphic zircons of MDC show a cooler temperature range of 740-640 °C, reflects the moderate ambient temperature of the lower crust during MDC emplacement. The MDC also provides a cautionary tale: in the absence of robust field and microstructural relations, the igneous-zoned zircon population at 122.1 ± 1.3 Ma, derived mostly from inherited zircons of the WFO, would be meaningless in terms of actual magmatic emplacement age of MDC, where the latter is further obscured by younger (ca. 114 Ma) metamorphic overgrowths

Lunar Flashlight and Other Lunar Cubesats

Science.gov (United States)

Cohen, Barbara

2017-01-01

Water is a human-exploitable resource. Lunar Flashlight is a Cubesat mission to detect and map lunar surface ice in permanently-shadowed regions of the lunar south pole. EM-1 will carry 13 Cubesat-class missions to further smallsat science and exploration capabilities; much room to infuse LEO cubesat methodology, models, and technology. Exploring the value of concurrent measurements to measure dynamical processes of water sources and sinks.

Our Lunar Destiny: Creating a Lunar Economy

Science.gov (United States)

Rohwer, Christopher J.

2000-01-01

"Our Lunar Destiny: Creating a Lunar Economy" supports a vision of people moving freely and economically between the earth and the Moon in an expansive space and lunar economy. It makes the economic case for the creation of a lunar space economy and projects the business plan that will make the venture an economic success. In addition, this paper argues that this vision can be created and sustained only by private enterprise and the legal right of private property in space and on the Moon. Finally, this paper advocates the use of lunar land grants as the key to unleashing the needed capital and the economic power of private enterprise in the creation of a 21st century lunar space economy. It is clear that the history of our United States economic system proves the value of private property rights in the creation of any new economy. It also teaches us that the successful development of new frontiers-those that provide economic opportunity for freedom-loving people-are frontiers that encourage, respect and protect the possession of private property and the fruits of labor and industry. Any new 21st century space and lunar economy should therefore be founded on this same principle.

Separation of zircon from the beach sand deposit of Srikurmam area, Srikakulam district, Andhra Pradesh - a case study

International Nuclear Information System (INIS)

Rao, G.V.S.U.; Sharma, A.K.; Seshadrinath, S.T.; Fahmi, Sohail; William Prasad, Ch.; Nagabhushanam, B.

2011-01-01

Beach sand placer deposits occur along the eastern and western coasts of India, which contain heavy minerals, such as ilmenite, rutile, garnet, monazite, zircon and sillimanite. Among these, zircon is used in zircaloys (nuclear industry), ceramics, refractories, abrasives, etc. Separation and chemical characterization of pure zircon is a prelude for understanding the different elements and impurities present and its industrial application. In recent times, several methods are developed for beneficiation and separation of individual heavy minerals from beach sands. In this paper, separation of zircon from beach sand of Srikurmam area, Andhra Pradesh was taken up as a case study. The process flow sheet adopted for separation and isolation of pure zircon from beach sand sample consists of desliming of beach sand, wet tabling of sand fraction, removal of magnetite by low intensity magnetic separation from table concentrate, perm roll magnetic separation and induced roll magnetic separation of table concentrate. The concentrates were further subjected to iso-dynamic magnetic separator after observing impurity present in the sample under binocular stereomicroscope. In the present process, about 95% pure zircon was obtained. Further concentration of zircon was carried out under the binocular stereomicroscope by hand picking of impurity to obtain 99.5% pure zircon concentrate. The pure zircon concentrate was analyzed for major, minor and trace elements by chemical method for characterization of zircon and cross validation of physical processes through which the zircon concentrate was obtained. Chemical analysis of the pure zircon concentrate indicated 63.15 to 64.79% ZrO 2 and 32.2 to 32.8% SiO 2 . These values are nearer to that of pure zircon, which stoichiometrically contains 67.2% ZrO 2 and 32.8 % SiO 2 with little iron. In the present study, ZrO 2 +HfO 2 content varies from 65.27 to 66.17% and hafnium from 1.25 to 1.46% HfO 2 in the zircon concentrate. The variation

Natural radioactivity and radon specific exhalation rate of zircon sands

International Nuclear Information System (INIS)

Righi, S.; Verita, S.; Bruzzi, L.; Albertazzi, A.

2006-01-01

The study focuses on the radon emanation from zircon sands and their derivatives, which are widely used in many sectors of industry. In particular, the results obtained by experimental measurements on samples of zircon sands and zircon flours commonly used in Italian ceramic industries are reported. Zircon sands contain a significant concentration of natural radioactivity because Th and U may substitute zirconium in the zircon crystal lattice. The relevant routes of exposure of workers to T.E.N.O.R.M. from zircon materials are external radiation and internal exposure, either by inhalation of aerosols in dusty working conditions or by inhalation of radon in workplaces. The main objective of this investigation is to provide experimental data able to better calculate the internal exposure of workers due to radon inhalation. Zircon samples were surveyed for natural radioactivity, radon specific exhalation rate and emanation fraction. Measurements of radioactivity concentration were carried out using γ-spectrometry. Methods used for determining radon consisted in determining the 222 Rn activity accumulated in a vessel after a given accumulation build-up time. The average activity concentrations of 238 U and 232 Th in samples result about 2600 and 550 Bq kg-1, respectively; these concentrations are significantly higher than the world average noticed in soils, rocks and Earth crust. The 222 Rn specific exhalation rates result very low probably due to the low porosity of the material and the consequent difficulty for radon to be released from the zircon crystal lattice. (author)

Influence of some additions on zircon synthesis and its properties

International Nuclear Information System (INIS)

Goryacheva, Z.E.; Poplevina, O.G.; Suvorov, S.A.; Toropov, A.N.

1978-01-01

Kinetics of zircon synthesis from pure ZrO 2 and SiO 2 is studied in the presence of additions of magnesium, calcium and rare earth oxides. The addition introduction accelerates zircon formation, its yield reaching 97% at 1600 deg C. Constants of zircon formation reaction rate are determined in the presence of additions of various oxides. It is shown that synthetic zircon surpasses the natural one in tensile and density properties at similar thermostability. It is stable to the effect of molten alkaline borosilicate glass and does not polute it

Mass spectrographic analysis of selected chemical elements by microbial leaching of zircon

International Nuclear Information System (INIS)

Becker, S.; Dietze, H.J.; Bullmann, M.; Iske, U.

1986-01-01

Spark source mass spectrometry is a useful method for chemical element analysis of geological and biological samples. This sensitive technique (detection limit down to the ppb-range) is used to analyze leaching processes by means of several microorganisms. The problem of microbial leaching of chemical resistent materials was tested under laboratory conditions with regard to possible analytical and technical applications. Leaching of metals with chemolithotrophic and heterotrophic, organic acids producing microorganisms has been investigated with zircon from the Baltic Shield containing 0.7% rare earth elements and 1.67% hafnium. When zircon is leached with strains of thiobacillus ferrooxidans about 80% of the rare earth elements, Hf, Th and U can be recovered. (orig.) [de

A Multi-Wavelength Grain-by-Grain Survey of Lunar Soils in Search of Rare Materials

Science.gov (United States)

Crites, S.; Lucey, P. G.; Viti, T.

2014-12-01

apatite and zircons. We are developing the capability to measure the 3 micron region to search for hydrated minerals. Our system also incorporates a micromanipulator which will be used for sorting of soils and isolation of grains of interest. We will report on the status of the system and progress towards identifying and isolating rare grains in lunar soils.

Deployable structures for a human lunar base

Science.gov (United States)

Gruber, Petra; Häuplik, Sandra; Imhof, Barbara; Özdemir, Kürsad; Waclavicek, Rene; Perino, Maria Antoinetta

2007-06-01

The study Lunar exploration architecture—deployable structures for a lunar base was performed within the Alcatel Alenia Space “Lunar Exploration Architecture” study for the European Space Agency. The purpose of the study was to investigate bionic concepts applicable to deployable structures and to interpret the findings for possible implementation concepts. The study aimed at finding innovative solutions for deployment possibilities. Translating folding/unfolding principles from nature, candidate geometries were developed and researched using models, drawings and visualisations. The use of materials, joints between structural elements and construction details were investigated for these conceptual approaches. Reference scenarios were used to identify the technical and environmental conditions, which served as design drivers. Mechanical issues and the investigation of deployment processes narrowed the selection down to six chosen concepts. Their applicability was evaluated at a conceptual stage in relation to the timescale of the mission.

Lunar CATALYST

Data.gov (United States)

National Aeronautics and Space Administration — Lunar Cargo Transportation and Landing by Soft Touchdown (Lunar CATALYST) is a NASA initiative to encourage the development of U.S. private-sector robotic lunar...

Generalized Software Architecture Applied to the Continuous Lunar Water Separation Process and the Lunar Greenhouse Amplifier

Science.gov (United States)

Perusich, Stephen; Moos, Thomas; Muscatello, Anthony

2011-01-01

This innovation provides the user with autonomous on-screen monitoring, embedded computations, and tabulated output for two new processes. The software was originally written for the Continuous Lunar Water Separation Process (CLWSP), but was found to be general enough to be applicable to the Lunar Greenhouse Amplifier (LGA) as well, with minor alterations. The resultant program should have general applicability to many laboratory processes (see figure). The objective for these programs was to create a software application that would provide both autonomous monitoring and data storage, along with manual manipulation. The software also allows operators the ability to input experimental changes and comments in real time without modifying the code itself. Common process elements, such as thermocouples, pressure transducers, and relative humidity sensors, are easily incorporated into the program in various configurations, along with specialized devices such as photodiode sensors. The goal of the CLWSP research project is to design, build, and test a new method to continuously separate, capture, and quantify water from a gas stream. The application is any In-Situ Resource Utilization (ISRU) process that desires to extract or produce water from lunar or planetary regolith. The present work is aimed at circumventing current problems and ultimately producing a system capable of continuous operation at moderate temperatures that can be scaled over a large capacity range depending on the ISRU process. The goal of the LGA research project is to design, build, and test a new type of greenhouse that could be used on the moon or Mars. The LGA uses super greenhouse gases (SGGs) to absorb long-wavelength radiation, thus creating a highly efficient greenhouse at a future lunar or Mars outpost. Silica-based glass, although highly efficient at trapping heat, is heavy, fragile, and not suitable for space greenhouse applications. Plastics are much lighter and resilient, but are not

Gender disparity in BMD conversion: a comparison between Lunar and Hologic densitometers.

Science.gov (United States)

Ganda, Kirtan; Nguyen, Tuan V; Pocock, Nicholas

2014-01-01

Female-derived inter-conversion and standardised BMD equations at the lumbar spine and hip have not been validated in men. This study of 110 male subjects scanned on Hologic and Lunar densitometers demonstrates that published equations may not applicable to men at the lumbar spine. Male inter-conversion equations have also been derived. Currently, available equations for inter-manufacturer conversion of bone mineral density (BMD) and calculation of standardised BMD (sBMD) are used in both males and females, despite being derived and validated only in women. Our aim was to test the validity of the published equations in men. One hundred ten men underwent lumbar spine (L2-4), femoral neck (FN) and total hip (TH) dual X-ray absorptiometry (DXA) using Hologic and Lunar scanners. Hologic BMD was converted to Lunar using published equations derived from women for L2-4 and FN. Actual Lunar BMD (A-Lunar) was compared to converted (Lunar equivalent) Hologic BMD values (H-Lunar). sBMD was calculated separately using Hologic (sBMD-H) and Lunar BMD (sBMD-L) at L2-4, FN and TH. Conversion equations in men for Hologic to Lunar BMD were derived using Deming regression analysis. There was a strong linear correlation between Lunar and Hologic BMD at all skeletal sites. A-Lunar BMD was however significantly higher than derived H-Lunar BMD (p Lunar BMD to Hologic BMD, and formulae for lumbar spine sBMD, derived in women may not be applicable to men.

Dating of zircons by the fission track method

International Nuclear Information System (INIS)

Tenorio Hernandez, L.M.

1992-01-01

This work describes the methodology to date zircons by the Fission Track Method. A brief discussion is made of the physical principles of the method, physical properties of zircons and the geochemical properties of uranium. When starting with a hand sample, a mineral separation is required; to do this the following steps are needed: crushing and sieving of the sample, washing and drying, magnetic separation, heavy liquid separation (Bromoform 2.89 g/cm 3 , Diyodomethane = 3.31 g/cm 3 ), and manual separation on a stereoscopic microscope. Once the zircon concentrate is obtained, these are mounted on a FEP teflon mount, then polished and etched on an eutectic mix of 10 g. of KOH + 7.2 g. of NaOH, heated to 210 Centigrade degrees. Afterwards the mounts are prepared for irradiation, sterilizing and putting on top of them an external detector (a thin sheet of muscovite poor in uranium content). The package is then wrapped in plastic and sent to the reactor together with standard zircons of known age (Fish Canyon Tuff: Naeser et.al., 1981), mounted in the same way, plus standard glasses of known uranium content. The package was irradiated in a site known as SIRCA (Rotatory Capsules Irradiation System). Then the package is left to decay for several days, and then the external detectors are etched in a 48% concentrated hydrofluoric acid for 5 minutes. Once the samples are processed through the mentioned steps, spontaneous tracks appear in the zircons and induced tracks appear in the external detectors. On counting the tracks one obtains ρ s (spontaneous track density) and ρ 1 (induced track density). These two parameters together with another one called '#zeta #' (obtained from the standard zircons and glasses), are used to obtain the age of the sample. Zircons from Cerro de Mercado, Durango were dated and the age obtained was 30 ±5 Ma. This date is in agreement with similar results obtained by Fleisher and Naeser (1975) for zircons of the same locality and dated by the

Detrital Zircons Split Sibumasu in East Gondwana

Science.gov (United States)

Zhang, X.; Chung, S. L.

2017-12-01

It is widely accepted that Sibumasu developed as a united terrane and originated from NW Australian margin in East Gondwana. Here we report new detrital zircon U-Pb-Hf isotopic data from Sumatra that, in combination with literature data, challenge and refute the above long-held view. In particular, the East and West Sumatra terranes share nearly identical Precambrian to Paleozoic detrital zircon age distributions and Hf isotopes, indicating a common provenance/origin for them. The Sumatra detrital zircons exhibit a prominent population of ca. 1170-1070 Ma, indistinguishable from those of the Lhasa and West Burma terranes, with detritus most probably sourcing from western Australia. By contrast, Sibuma (Sibumasu excluding Sumatra) detrital zircons display a prevailing population of ca. 980-935 Ma, strongly resembling those of the western Qiangtang terrane, with detrital materials most likely derived from Greater India and Himalayas. Such markedly distinct detrital zircon age profiles between Sumatra and Sibuma require disparate sources/origin for them, provoking disintegration of the widely-adopted, but outdated, term Sibumasu and thus inviting a new configuration of East Gondwana in the early Paleozoic, with Sumatra and West Burma lying outboard the Lhasa terrane in the NW Australian margin and Sibuma situated in the northern Greater Indian margin. More future investigations are needed to establish the precise rifting and drifting histories of Sumatra and Sibuma, as two separated terranes, during the breakup of Gondwana.

Year 3 LUNAR Annual Report to the NASA Lunar Science Institute

OpenAIRE

Burns, Jack; Lazio, Joseph

2012-01-01

The Lunar University Network for Astrophysics Research (LUNAR) is a team of researchers and students at leading universities, NASA centers, and federal research laboratories undertaking investigations aimed at using the Moon as a platform for space science. LUNAR research includes Lunar Interior Physics & Gravitation using Lunar Laser Ranging (LLR), Low Frequency Cosmology and Astrophysics (LFCA), Planetary Science and the Lunar Ionosphere, Radio Heliophysics, and Exploration Science. The LUN...

Direct Chlorination of Zircon Sand

International Nuclear Information System (INIS)

Dwiretnani Sudjoko; Budi Sulistyo; Pristi Hartati; Sunardjo

2002-01-01

It was investigated the direct chlorination of zircon sand in a unit chlorination equipment. The process was in semi batch. The product gas was scrubbed in aqueous NaOH. It was search the influence of time, ratio of reactant and size of particle sand to the concentration of Zr and Si in the product. From these research it was found that as the times, ratio of reactant increased, the concentration of Zr increased, but the concentration of Si decreased, while as grain size of zircon sand decreased the concentration of Zr decreased, but the concentration of Si increased. (author)

Using the Lunar Phases Concept Inventory to Investigate College Students' Pre-instructional Mental Models of Lunar Phases

Science.gov (United States)

Lindell, Rebecca S.; Sommer, Steven R.

2004-09-01

The Lunar Phases Concept Inventory (LPCI) is a twenty-item multiple-choice inventory developed to aid instructors in assessing the mental models their students utilize when answering questions concerning phases of the moon. Based upon an in-depth qualitative investigation of students' understanding of lunar phases, the LPCI was designed to take advantage of the innovative model analysis theory to probe the different dimensions of students' mental models of lunar phases. As part of a national field test, pre-instructional LPCI data was collected for over 750 students from multiple post-secondary institutions across the United States and Canada. Application of model analysis theory to this data set allowed researchers to probe the different mental models of lunar phases students across the country utilize prior to instruction. Results of this analysis display strikingly similar results for the different institutions, suggesting a potential underlying cognitive framework.

Empirical constraints on the effects of radiation damage on helium diffusion in zircon

Science.gov (United States)

Anderson, Alyssa J.; Hodges, Kip V.; van Soest, Matthijs C.

2017-12-01

In this study, we empirically evaluate the impact of radiation damage on zircon (U-Th)/He closure temperatures for a suite of zircon crystals from the slowly cooled McClure Mountain syenite of south-central Colorado, USA. We present new zircon, titanite, and apatite conventional (U-Th)/He dates, zircon laser ablation (U-Th)/He and U-Pb dates, and zircon Raman spectra for crystals from the syenite. Titanite and apatite (U-Th)/He dates range from 447 to 523 Ma and 88.0 to 138.9 Ma, respectively, and display no clear correlation between (U-Th)/He date and effective uranium concentration. Conventional zircon (U-Th)/He dates range from 230.3 to 474 Ma, while laser ablation zircon (U-Th)/He dates show even greater dispersion, ranging from 5.31 to 520 Ma. Dates from both zircon (U-Th)/He datasets decrease with increasing alpha dose, indicating that most of the dispersion can be attributed to radiation damage. Alpha dose values for the dated zircon crystals range from effectively zero to 2.15 × 1019 α /g, spanning the complete damage spectrum. We use an independently constrained thermal model to empirically assign a closure temperature to each dated zircon grain. If we assume that this thermal model is robust, the zircon radiation damage accumulation and annealing model of Guenthner et al. (2013) does not accurately predict closure temperatures for many of the analyzed zircon crystals. Raman maps of the zircons dated by laser ablation document complex radiation damage zoning, sometimes revealing crystalline zones in grains with alpha dose values suggestive of amorphous material. Such zoning likely resulted in heterogeneous intra-crystalline helium diffusion and may help explain some of the discrepancies between our empirical findings and the Guenthner et al. (2013) model predictions. Because U-Th zoning is a common feature in zircon, radiation damage zoning is likely to be a concern for most ancient, slowly cooled zircon (U-Th)/He datasets. Whenever possible, multiple

Silicic melt evolution in the early Izu-Bonin arc recorded in detrital zircons: Zircon U-Pb geochronology and trace element geochemistry for Site U1438, Amami Sankaku Basin

Science.gov (United States)

Barth, A. P.; Tani, K.; Meffre, S.; Wooden, J. L.; Coble, M. A.

2016-12-01

Understanding the petrologic evolution of oceanic arc magmas through time is important because these arcs reveal the processes of formation and the early evolution of juvenile continental crust. The Izu-Bonin (IB) arc system has been targeted because it is one of several western Pacific intraoceanic arcs initiated at 50 Ma and because of its prominent spatial asymmetry, with widespread development of relatively enriched rear arc lavas. We examined Pb/U and trace element compositions in zircons recovered at IODP Site 351-U1438 and compared them to regional and global zircon suites. These new arc zircon data indicate that detrital zircons will yield new insights into the generation of IB silicic melts and form a set of useful geochemical proxies for interpreting ancient arc detrital zircon provenance. Project IBM drilling target IBM1 was explored by Expedition 351 at Site U1438, located in the proximal back-arc of the northern Kyushu-Palau Ridge (KPR) at 27.3°N. A 1.2 km thick section of Paleogene volcaniclastic rocks, increasingly lithified and hydrothermally altered with depth, constitutes a proximal rear arc sedimentary record of IB arc initiation and early arc evolution. The ages and compositions of U1438 zircons are compatible with provenance in one or more edifices of the northern KPR and are incompatible with drilling contamination. Melt zircon saturation temperatures and Ti-in-zircon thermometry suggest a provenance in relatively cool and silicic KPR melts. The abundances of selected trace elements with high native concentrations provide insight into the petrogenesis of U1438 detrital zircon host melts, and may be useful indicators of both short and long-term variations in melt compositions in arc settings. The U1438 zircons are slightly enriched in U and LREE and are depleted in Nb compared to zircons from mid-ocean ridges and the Parece-Vela Basin, as predicted for melts in a primitive oceanic arc setting with magmas derived from a highly depleted mantle

SiGe Based Low Temperature Electronics for Lunar Surface Applications

Science.gov (United States)

Mojarradi, Mohammad M.; Kolawa, Elizabeth; Blalock, Benjamin; Cressler, John

2012-01-01

The temperature at the permanently shadowed regions of the moon's surface is approximately -240 C. Other areas of the lunar surface experience temperatures that vary between 120 C and -180 C during the day and night respectively. To protect against the large temperature variations of the moon surface, traditional electronics used in lunar robotics systems are placed inside a thermally controlled housing which is bulky, consumes power and adds complexity to the integration and test. SiGe Based electronics have the capability to operate over wide temperature range like that of the lunar surface. Deploying low temperature SiGe electronics in a lander platform can minimize the need for the central thermal protection system and enable the development of a new generation of landers and mobility platforms with highly efficient distributed architecture. For the past five years a team consisting of NASA, university and industry researchers has been examining the low temperature and wide temperature characteristic of SiGe based transistors for developing electronics for wide temperature needs of NASA environments such as the Moon, Titan, Mars and Europa. This presentation reports on the status of the development of wide temperature SiGe based electronics for the landers and lunar surface mobility systems.

Electromagnetic energy applied to and gained from lunar materials

International Nuclear Information System (INIS)

Meek, T.T.; Vaniman, D.T.; Blake, R.D.; Cocks, F.H.

1986-01-01

Electromagnetic energy may be useful in microwave frequencies for in-situ melting or sintering of lunar regolith. Simple configurations of magnetron or gyrotron tubes might be constructed for unique melting geometries. For energy production, lunar ilmenite has potential applications in photovoltaic devices. 11 refs., 11 figs

Thermoluminescence of zircon: a kinetic model

CERN Document Server

Turkin, A A; Vainshtein, D I; Hartog, H W D

2003-01-01

The mineral zircon, ZrSiO sub 4 , belongs to a class of promising materials for geochronometry by means of thermoluminescence (TL) dating. The development of a reliable and reproducible method for TL dating with zircon requires detailed knowledge of the processes taking place during exposure to ionizing radiation, long-term storage, annealing at moderate temperatures and heating at a constant rate (TL measurements). To understand these processes one needs a kinetic model of TL. This paper is devoted to the construction of such a model. The goal is to study the qualitative behaviour of the system and to determine the parameters and processes controlling TL phenomena of zircon. The model considers the following processes: (i) Filling of electron and hole traps at the excitation stage as a function of the dose rate and the dose for both (low dose rate) natural and (high dose rate) laboratory irradiation. (ii) Time dependence of TL fading in samples irradiated under laboratory conditions. (iii) Short time anneali...

Lunar Riometry

Science.gov (United States)

Lazio, J.; Jones, D. L.; MacDowall, R. J.; Burns, J. O.; Kasper, J. C.

2011-12-01

The lunar exosphere is the exemplar of a plasma near the surface of an airless body. Exposed to both the solar and interstellar radiation fields, the lunar exosphere is mostly ionized, and enduring questions regarding its properties include its density and vertical extent and its behavior over time, including modification by landers. Relative ionospheric measurements (riometry) are based on the simple physical principle that electromagnetic waves cannot propagate through a partially or fully ionized medium below the plasma frequency, and riometers have been deployed on the Earth in numerous remote and hostile environments. A multi-frequency riometer on the lunar surface would be able to monitor, in situ, the peak plasma density of the lunar exosphere over time. We describe a concept for a riometer implemented as a secondary science payload on future lunar landers, such as those recommended in the recent Planetary Sciences Decadal Survey report. While the prime mission of such a riometer would be probing the lunar exosphere, our concept would also be capable to measuring the properties of nanometer- to micron-scale dust. The LUNAR consortium is funded by the NASA Lunar Science Institute to investigate concepts for astrophysical observatories on the Moon. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA.

Pengaruh Temperatur, Waktu, dan Aditif Dalam Pembuatan Zircon Micronized

Directory of Open Access Journals (Sweden)

Sajima

2017-05-01

Full Text Available Research on temperature, time and additives effects on milling process in micronized-zircon production has been conducted. The production of zircon micronized started from sorting process on mining products then followed by beneficiation, roasting, leaching, dryng and milling processes. The results showed that the optimum conditions of the roasting process was at the temperature of 425 °C, in 25 minutes and using 4% additives. In these conditions, micronized zircon (2 µm obtained as much as 92.10% in10 minutes milling time.

Investigations on microbial leaching of zircon by means of spark source mass spectrometry

International Nuclear Information System (INIS)

Becker, S.; Dietze, H.J.; Bullmann, M.; Iske, U.

1985-01-01

Spark source mass spectrometry is a useful method for chemical element analysis of geological and biological samples. This sensitive technique (detection limit down to the ppb-range) is used to analyze leaching processes by means of several microorganisms. The problem of microbial leaching of chemical resistent materials was tested under laboratory condition with regard to possible analytical and technical applications. Leaching of metalls with chemolithotrophic and heterotrophic, organic acids producing microorganisms has been investigated with zircon from Baltic Shield containing 0.7% rare earth elements and 1.67% hafnium. When zircon is leached with strains of Thiobacillus ferroxidans the rare earth elements, Hf, Th, and U mostly (about 80%) can be recovered. (author)

U-Th-Pb systematics in zircon and titanite

International Nuclear Information System (INIS)

Zartman, R.E.; Kwak, L.M.

1990-01-01

U-Th-Pb isotopic analyses of zircon and titanite were made for two core samples of granite from borehole ATK-1 drilled into the Eye-Dashwa Lakes pluton. One of the samples from near the bottom of the hole (990.97 to 996.78 m) yielded zircon and titanite that were slightly to severely disturbed isotopically. Eight fractions of zircon give an upper concordia intercept age of 2625 ± 16 Ma (MSWD = 34), which, based on an evaluation of the more concordant data points and on other geochronological results, is interpreted as being slightly too young. The time of crystallization is probably better approximated by the 207 Pb/ 206 Pb age of 2665 Ma determined on a slightly (∼8 percent) discordant titanite. The other sample from near the surface (3.85 to 9.61 m) generally revealed even more severely disturbed isotopic systematics for both zircon and titanite. The complex nature of the disturbances probably resulted from the penetration of meteoritic water into rock already modified by post-crystallization hydrothermal alteration. Nuclide migration occurred in both minerals -- during the Middle or Late Proterozoic for the zircon and during the modern weathering cycle for the titanite. Material balance calculations are used to demonstrate a recent relative gain of radiogenic Pb and/or loss of Th and U from the freshest-looking, least-altered titanite by exchange with altered, leucoxenite-bearing titanite

Spectroscopic determination of optimal hydration time of zircon surface

Energy Technology Data Exchange (ETDEWEB)

Ordonez R, E. [ININ, Departamento de Quimica, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Garcia R, G. [Instituto Tecnologico de Toluca, Division de Estudios del Posgrado, Av. Tecnologico s/n, Ex-Rancho La Virgen, 52140 Metepec, Estado de Mexico (Mexico); Garcia G, N., E-mail: eduardo.ordonez@inin.gob.m [Universidad Autonoma del Estado de Mexico, Facultad de Quimica, Av. Colon y Av. Tollocan, 50180 Toluca, Estado de Mexico (Mexico)

2010-07-01

When a mineral surface is immersed in an aqueous solution, it develops and electric charge produced by the amphoteric dissociation of hydroxyl groups created by the hydration of the solid surface. This is one influential surface property. The complete hydration process takes a time which is specific for each mineral species. The knowledge of the aqueous solution contact time for complete surface hydration is mandatory for further surface phenomena studies. This study deals with the optimal hydration time of the raw zircon (ZrSiO{sub 4}) surface comparing the classical potentiometric titrations with a fluorescence spectroscopy technique. The latter is easy and rea liable as it demands only one sample batch to determine the optimal time to ensure a total hydration of the zircon surface. The analytical results of neutron activation analysis showed the presence of trace quantities of Dy{sup 3+}, Eu{sup 3+} and Er{sup 3} in the bulk of zircon. The Dy{sup 3+} is structured in the zircon crystalline lattice and undergoes the same chemical reactions as zircon. Furthermore, the Dy{sup 3+} has a good fluorescent response whose intensity is enhanced by hydration molecules. The results show that, according to the potentiometric analysis, the hydration process for each batch (at least 8 sample batches) takes around 2 h, while the spectrometric method indicates only 5 minutes from only one batch. Both methods showed that the zircon surface have a 16 h optimal hydration time. (Author)

Spectroscopic determination of optimal hydration time of zircon surface

International Nuclear Information System (INIS)

Ordonez R, E.; Garcia R, G.; Garcia G, N.

2010-01-01

When a mineral surface is immersed in an aqueous solution, it develops and electric charge produced by the amphoteric dissociation of hydroxyl groups created by the hydration of the solid surface. This is one influential surface property. The complete hydration process takes a time which is specific for each mineral species. The knowledge of the aqueous solution contact time for complete surface hydration is mandatory for further surface phenomena studies. This study deals with the optimal hydration time of the raw zircon (ZrSiO 4 ) surface comparing the classical potentiometric titrations with a fluorescence spectroscopy technique. The latter is easy and rea liable as it demands only one sample batch to determine the optimal time to ensure a total hydration of the zircon surface. The analytical results of neutron activation analysis showed the presence of trace quantities of Dy 3+ , Eu 3+ and Er 3 in the bulk of zircon. The Dy 3+ is structured in the zircon crystalline lattice and undergoes the same chemical reactions as zircon. Furthermore, the Dy 3+ has a good fluorescent response whose intensity is enhanced by hydration molecules. The results show that, according to the potentiometric analysis, the hydration process for each batch (at least 8 sample batches) takes around 2 h, while the spectrometric method indicates only 5 minutes from only one batch. Both methods showed that the zircon surface have a 16 h optimal hydration time. (Author)

Two-stage model of development of heterogeneous uranium-lead systems in zircon

International Nuclear Information System (INIS)

Mel'nikov, N.N.; Zevchenkov, O.A.

1985-01-01

Behaviour of isotope systems of multiphase zircons at their two-stage distortion is considered. The results of calculations testify to the fact that linear correlations on the diagram with concordance can be explained including two-stage discovery of U-Pb systems of cogenetic zircons if zircon is considered physically heterogeneous and losing in its different part different ratios of accumulated radiogenic lead. ''Metamorphism ages'' obtained by these two-stage opening zircons are intermediate, and they not have geochronological significance while ''crystallization ages'' remain rather close to real ones. Two-stage opening zircons in some cases can be diagnosed by discordance of their crystal component

Topography of the Lunar Poles and Application to Geodesy with the Lunar Reconnaissance Orbiter

Science.gov (United States)

Mazarico, Erwan; Neumann, Gregory A.; Rowlands, David D.; Smith, David E.; Zuber, Maria T.

2012-01-01

The Lunar Orbiter Laser Altimeter (LOLA) [1] onboard the Lunar Reconnaissance Orbiter (LRO) [2] has been operating continuously since July 2009 [3], accumulating approx.5.4 billion measurements from 2 billion on-orbit laser shots. LRO s near-polar orbit results in very high data density in the immediate vicinity of the lunar poles, which are each sampled every 2h. With more than 10,000 orbits, high-resolution maps can be constructed [4] and studied [5]. However, this requires careful processing of the raw data, as subtle errors in the spacecraft position and pointing can lead to visible artifacts in the final map. In other locations on the Moon, ground tracks are subparallel and longitudinal separations are typically a few hundred meters. Near the poles, the track intersection angles can be large and the inter-track spacing is small (above 80 latitude, the effective resolution is better than 50m). Precision Orbit Determination (POD) of the LRO spacecraft [6] was performed to satisfy the LOLA and LRO mission requirements, which lead to a significant improvement in the orbit position knowledge over the short-release navigation products. However, with pixel resolutions of 10 to 25 meters, artifacts due to orbit reconstruction still exist. Here, we show how the complete LOLA dataset at both poles can be adjusted geometrically to produce a high-accuracy, high-resolution maps with minimal track artifacts. We also describe how those maps can then feedback to the POD work, by providing topographic base maps with which individual LOLA altimetric measurements can be contributing to orbit changes. These direct altimetry constraints improve accuracy and can be used more simply than the altimetric crossovers [6].

Crystallization process of zircon and fergusonite during hydrothermal alteration in Nechalacho REE deposit, Thor Lake, Canada

Science.gov (United States)

Hoshino, M.; Watanabe, Y.; Murakami, H.; Kon, Y.; Tsunematsu, M.

2012-04-01

The core samples of two drill holes, which penetrate sub-horizontal mineralized horizons at Nechalacho REE deposit in the Proterozoic Thor Lake syenite, Canada, were studied in order to clarify magmatic and hydrothermal processes that enriched HFSE (e.g. Zr, Nb, Y and REE). Zircon is the most common REE minerals in Nechalacho REE deposit. The zircon is divided into five types as follows: Type-1 zircon occurs as single grain in phlogopite and the chondrite-normalized REE pattern is characterized by a steeply-rising slope from the LREE to the HREE with a positive Ce-anomaly and negative Eu-anomaly. This chemical characteristic is similar to that of igneous zircon. Type-2 zircon consists of HREE-rich magmatic porous core and LREE-Nb-F-rich hydrothermal rim. This type zircon is mostly included in phlogopite and fluorite, and occasionally in microcline. Type-3 zircon is characterized by euhedral to anhedral crystal, occurring in a complex intergrowth with REE fluorocarbonates. Type-3 zircons have high contents of REE, Nb and fluorine. Type-4 zircon consists of porous-core and -rim zones, but their chemical compositions are similar to each other. This type zircon is a subhedral crystal rimmed by fergusonite. Type-5 zircon is characterized by smaller, porous and subhedral to anhedral crystals. The interstices between small zircons are filled by fergusonite. Type-4 and -5 zircons show low REE and Nb contents. Occurrences of these five types of zircon are different according to the depth and degree of the alteration by hydrothermal solutions rich in F- and CO3 of the two drill holes, which permit a model for evolution of the zircon crystallization in Nechalacho REE deposit as follows: (1) type-1 (single magmatic zircon) is formed in miaskitic syenite. (2) LREE-Nb-F-rich hydrothermal zircon formed around HREE-rich magmatic zircon (type-2 zircon); (3) type-3 zircon crystallized thorough F and CO3-rich hydrothermal alteration of type-2 zircon which formed the complex

Developing Zircon as a Probe of Planetary Impact History

Science.gov (United States)

Wielicki, Matthew

2014-12-01

The identification of Meteor Crater in Arizona as an extraterrestrial impact by Eugene Shoemaker provided the first evidence of this geologic phenomenon and opened the door to a new field of research that has eventually lead to the identification of over ~150 terrestrial impact structures. Subsequently impacts have been evoked in the formation of the moon, delivery of volatiles and bio-precursors to early Earth, creation of habitats for the earliest life and, in more recent times, major mass extinction events. However, understanding the impact flux to the Earth-Moon system has been complicated by the constant weathering and erosion at Earth's surface and the complex nature of impactite samples such that only a hand full of terrestrial craters have been accurately and precisely dated. Currently 40Ar/39Ar step-heating analysis of impactite samples is commonly used to infer impact ages but can be problematic due to the presence of relic clasts, incomplete 40Ar outgassing or excess 40Ar, and recoil and shock effects. The work presented here attempts to develop zircon geochronology to probe planetary impact histories as an alternative to current methods and provides another tool by which to constrain the bolide flux to the Earth-Moon system. Zircon has become the premier geo-chronometer in earth science and geochemical investigation of Hadean zircon from Western Australia has challenged the long-standing, popular conception that the near-surface Hadean Earth was an uninhabitable and hellish world; Zircons may preserve environmental information regarding their formation and thus provide a rare window into conditions on early Earth. Isotopic and petrologic analyses of these ancient grains have been interpreted to suggest that early Earth was more habitable than previously envisioned, with water oceans, continental crust, and possibly even plate tectonics. The Hadean is also suspected to be a time of major planetary bombardment however identifying impact signatures within

Lunar Health Monitor (LHM)

Science.gov (United States)

Lisy, Frederick J.

2015-01-01

Orbital Research, Inc., has developed a low-profile, wearable sensor suite for monitoring astronaut health in both intravehicular and extravehicular activities. The Lunar Health Monitor measures respiration, body temperature, electrocardiogram (EKG) heart rate, and other cardiac functions. Orbital Research's dry recording electrode is central to the innovation and can be incorporated into garments, eliminating the need for conductive pastes, adhesives, or gels. The patented dry recording electrode has been approved by the U.S. Food and Drug Administration. The LHM is easily worn under flight gear or with civilian clothing, making the system completely versatile for applications where continuous physiological monitoring is needed. During Phase II, Orbital Research developed a second-generation LHM that allows sensor customization for specific monitoring applications and anatomical constraints. Evaluations included graded exercise tests, lunar mission task simulations, functional battery tests, and resting measures. The LHM represents the successful integration of sensors into a wearable platform to capture long-duration and ambulatory physiological markers.

Lunar Reconnaissance Orbiter Lunar Workshops for Educators

Science.gov (United States)

Jones, A. P.; Hsu, B. C.; Hessen, K.; Bleacher, L.

2012-12-01

The Lunar Workshops for Educators (LWEs) are a series of weeklong professional development workshops, accompanied by quarterly follow-up sessions, designed to educate and inspire grade 6-12 science teachers, sponsored by the Lunar Reconnaissance Orbiter (LRO). Participants learn about lunar science and exploration, gain tools to help address common student misconceptions about the Moon, find out about the latest research results from LRO scientists, work with data from LRO and other lunar missions, and learn how to bring these data to their students using hands-on activities aligned with grade 6-12 National Science Education Standards and Benchmarks and through authentic research experiences. LWEs are held around the country, primarily in locations underserved with respect to NASA workshops. Where possible, workshops also include tours of science facilities or field trips intended to help participants better understand mission operations or geologic processes relevant to the Moon. Scientist and engineer involvement is a central tenant of the LWEs. LRO scientists and engineers, as well as scientists working on other lunar missions, present their research or activities to the workshop participants and answer questions about lunar science and exploration. This interaction with the scientists and engineers is consistently ranked by the LWE participants as one of the most interesting and inspiring components of the workshops. Evaluation results from the 2010 and 2011 workshops, as well as preliminary analysis of survey responses from 2012 participants, demonstrated an improved understanding of lunar science concepts among LWE participants in post-workshop assessments (as compared to identical pre-assessments) and a greater understanding of how to access and effectively share LRO data with students. Teachers reported increased confidence in helping students conduct research using lunar data, and learned about programs that would allow their students to make authentic

Lunar cement

Science.gov (United States)

Agosto, William N.

1992-01-01

With the exception of water, the major oxide constituents of terrestrial cements are present at all nine lunar sites from which samples have been returned. However, with the exception of relatively rare cristobalite, the lunar oxides are not present as individual phases but are combined in silicates and in mixed oxides. Lime (CaO) is most abundant on the Moon in the plagioclase (CaAl2Si2O8) of highland anorthosites. It may be possible to enrich the lime content of anorthite to levels like those of Portland cement by pyrolyzing it with lunar-derived phosphate. The phosphate consumed in such a reaction can be regenerated by reacting the phosphorus product with lunar augite pyroxenes at elevated temperatures. Other possible sources of lunar phosphate and other oxides are discussed.

Connecting Returned Apollo Soils and Remote Sensing: Application to the Diviner Lunar Radiometer

Science.gov (United States)

Greenhagen, B. T.; DonaldsonHanna, K. L.; Thomas, I. R.; Bowles, N. E.; Allen, Carlton C.; Pieters, C. M.; Paige, D. A.

2014-01-01

The Diviner Lunar Radiometer, onboard NASA's Lunar Reconnaissance Orbiter, has produced the first global, high resolution, thermal infrared observations of an airless body. The Moon, which is the most accessible member of this most abundant class of solar system objects, is also the only body for which we have extraterrestrial samples with known spatial context, returned Apollo samples. Here we present the results of a comprehensive study to reproduce an accurate simulated lunar environment, evaluate the most appropriate sample and measurement conditions, collect thermal infrared spectra of a representative suite of Apollo soils, and correlate them with Diviner observations of the lunar surface. It has been established previously that thermal infrared spectra measured in simulated lunar environment (SLE) are significantly altered from spectra measured under terrestrial or martian conditions. The data presented here were collected at the University of Oxford Simulated Lunar Environment Chamber (SLEC). In SLEC, we simulate the lunar environment by: (1) pumping the chamber to vacuum pressures (less than 10-4 mbar) sufficient to simulate lunar heat transport processes within the sample, (2) cooling the chamber with liquid nitrogen to simulate radiation to the cold space environment, and (3) heating the samples with heaters and lamp to set-up thermal gradients similar to those experienced in the upper hundreds of microns of the lunar surface. We then conducted a comprehensive suite of experiments using different sample preparation and heating conditions on Apollo soils 15071 (maria) and 67701 (highland) and compared the results to Diviner noontime data to select the optimal experimental conditions. This study includes thermal infrared SLE measurements of 10084 (A11 - LM), 12001 (A12 - LM), 14259 (A14 - LM), 15071 (A15 - S1), 15601 (A15 - S9a), 61141 (A16 - S1), 66031 (A16 - S6), 67701 (A16 - S11), and 70181 (A17 - LM). The Diviner dataset includes all six Apollo sites

Annealing effects on cathodoluminescence of zircon

Science.gov (United States)

Tsuchiya, Y.; Nishido, H.; Noumi, Y.

2011-12-01

U-Pb zircon dating (e. g., SHRIMP) is an important tool to interpret a history of the minerals at a micrometer-scale, where cathodoluminescence (CL) imaging allows us to recognize internal zones and domains with different chemical compositions and structural disorder at high spatial resolution. The CL of zircon is attributed by various types of emission centers, which are extrinsic ones such as REE impurities and intrinsic ones such as structural defects. Metamictization resulted from radiation damage to the lattice by alpha particles from the decay of U and Th mostly causes an effect on the CL features of zircon as a defect center. However, slightly radiation-damaged zircon, which is almost nondetectable by XRD, has not been characterized using CL method. In this study, annealing effects on CL of zircon has been investigated to clarify a recovery process of the damaged lattice at low radiation dose. A single crystal of zircon from Malawi was selected for CL measurements. It contains HfO2: 2.30 w.t %, U: 241 ppm and Th: 177 ppm. Two plate samples perpendicular to c and a axes were prepared for annealing experiments during 12 hours from room temperature to 1400 degree C. Color CL images were captured using a cold-cathode microscope (Luminoscope: Nuclide ELM-3R). CL spectral measurements were conducted using an SEM (JEOL: JSM-5410) combined with a grating monochromator (Oxford: Mono CL2) to measure CL spectra ranging from 300 to 800 nm in 1 nm steps with a temperature controlled stage. The dispersed CL was collected by a photoncounting method using a photomultiplier tube (Hamamatsu: R2228) and converted to digital data. All CL spectra were corrected for the total instrumental response. Spectral analysis reveals an anisotropy of the CL emission bands related to intrinsic defect center in blue region, radiation-induced defect center from 500 to 700 nm, and trivalent Dy impurity center at 480 and 580 nm, but their relative intensities are almost constant. CL on the

Lunar feldspathic meteorites: Constraints on the geology of the lunar highlands, and the origin of the lunar crust

Science.gov (United States)

Gross, Juliane; Treiman, Allan H.; Mercer, Celestine N.

2014-02-01

The composition of the lunar crust provides clues about the processes that formed it and hence contains information on the origin and evolution of the Moon. Current understanding of lunar evolution is built on the Lunar Magma Ocean hypothesis that early in its history, the Moon was wholly or mostly molten. This hypothesis is based on analyses of Apollo samples of ferroan anorthosites (>90% plagioclase; molar Mg/(Mg+Fe)=Mg#Moon's surface, and remote sensing data, show that ferroan anorthosites are not globally distributed and that the Apollo highland samples, used as a basis for the model, are influenced by ejecta from the Imbrium basin. In this study we evaluate anorthosites from all currently available adequately described lunar highland meteorites, representing a more widespread sampling of the lunar highlands than Apollo samples alone, and find that ∼80% of them are significantly more magnesian than Apollo ferroan anorthosites. Interestingly, Luna mission anorthosites, collected outside the continuous Imbrium ejecta, are also highly magnesian. If the lunar highland crust consists dominantly of magnesian anorthosites, as suggested by their abundance in samples sourced outside Imbrium ejecta, a reevaluation of the Lunar Magma Ocean model is a sensible step forward in the endeavor to understand lunar evolution. Our results demonstrate that lunar anorthosites are more similar in their chemical trends and mineral abundance to terrestrial massif anorthosites than to anorthosites predicted in a Lunar Magma Ocean. This analysis does not invalidate the idea of a Lunar Magma Ocean, which seems a necessity under the giant impact hypothesis for the origin of the moon. However, it does indicate that most rocks now seen at the Moon's surface are not primary products of a magma ocean alone, but are products of more complex crustal processes.

Photometric Lunar Surface Reconstruction

Science.gov (United States)

Nefian, Ara V.; Alexandrov, Oleg; Morattlo, Zachary; Kim, Taemin; Beyer, Ross A.

2013-01-01

Accurate photometric reconstruction of the Lunar surface is important in the context of upcoming NASA robotic missions to the Moon and in giving a more accurate understanding of the Lunar soil composition. This paper describes a novel approach for joint estimation of Lunar albedo, camera exposure time, and photometric parameters that utilizes an accurate Lunar-Lambertian reflectance model and previously derived Lunar topography of the area visualized during the Apollo missions. The method introduced here is used in creating the largest Lunar albedo map (16% of the Lunar surface) at the resolution of 10 meters/pixel.

Building an Economical and Sustainable Lunar Infrastructure to Enable Lunar Industrialization

Science.gov (United States)

Zuniga, Allison F.; Turner, Mark; Rasky, Daniel; Loucks, Mike; Carrico, John; Policastri, Daniel

2017-01-01

A new concept study was initiated to examine the architecture needed to gradually develop an economical, evolvable and sustainable lunar infrastructure using a public/private partnerships approach. This approach would establish partnership agreements between NASA and industry teams to develop a lunar infrastructure system that would be mutually beneficial. This approach would also require NASA and its industry partners to share costs in the development phase and then transfer operation of these infrastructure services back to its industry owners in the execution phase. These infrastructure services may include but are not limited to the following: lunar cargo transportation, power stations, communication towers and satellites, autonomous rover operations, landing pads and resource extraction operations. The public/private partnerships approach used in this study leveraged best practices from NASA's Commercial Orbital Transportation Services (COTS) program which introduced an innovative and economical approach for partnering with industry to develop commercial cargo services to the International Space Station. This program was planned together with the ISS Commercial Resupply Services (CRS) contracts which was responsible for initiating commercial cargo delivery services to the ISS for the first time. The public/private partnerships approach undertaken in the COTS program proved to be very successful in dramatically reducing development costs for these ISS cargo delivery services as well as substantially reducing operational costs. To continue on this successful path towards installing economical infrastructure services for LEO and beyond, this new study, named Lunar COTS (Commercial Operations and Transport Services), was conducted to examine extending the NASA COTS model to cis-lunar space and the lunar surface. The goals of the Lunar COTS concept are to: 1) develop and demonstrate affordable and commercial cis-lunar and surface capabilities, such as lunar cargo

Peculiar Feldspar And Quartz Inclusions Within Zircons From Anorthosites, North Eastern Desert, Egypt

Science.gov (United States)

Eliwa, H. A.; Dawoud, M. I.; Khalaf, I. M.; Negendank, J. F.; Itaya, T.

2004-12-01

Zircons from three anorthosite outcrops along Wadi Dib area, north Eastern Desert of Egypt contain abundant and conspicuous inclusions of quartz, feldspar, amphibole and apatite. These anorthosites, as (50-100m thick) layers, represent the top of mafic-ultramafic intrusions exhibiting rhythmic layering visible by reputation of melanocratic and leucocratic layers. Field and microscopic studies exhibit that these anorthosites were affected by the action of residual magmatic solutions associated with the late stage crystallization of the younger granites, which modified their mineralogical composition. They are composed totally of plagioclase with subordinate amount of clinoenstatite, augite, amphibole, biotite, K-feldspar, and quartz. Accessories are magnetite, ilmenite, apatite and zircon. The abundance and the mode of occurrence of K-feldspar, quartz, and biotite with apatite and zircon among the megacrysts suggest their formation is ascribed to the interaction with the residual solutions. The microprobe data exhibit difference between feldspar and amphiboles contained herein zircons and those as anorthosite mineral constituents. The genetic relationship between zircons and their inclusions suggests later growth of zircons than inclusions and most probably at the final stage of rock modification. Zircons are magmatic and found in the interstitial feldspar and quartz among plagioclase megacrysts in aggregates or as individual grains. The microscopic and SEM images investigation exhibit that most zircons are subhedral to euhedral equant and prismatic crystals. Most zircons have same range of crystal morphologies and internal growth structures with predominance of prism /{100/} and pyramid /{101/} and occasionally prism /{110/} and pyramid /{111/}. No evidences for poly-faceted grains, inherited cores or later overgrowths were detected. CL images distinguished zircons with visible core-rim structures and others with regular and continuous growth zones contained herein

Zircon U-Pb ages of Guyana greenstone-gneiss terrane

Energy Technology Data Exchange (ETDEWEB)

Gibbs, A.K. (Cornell Univ., Ithaca, NY (USA)); Olszewski, W.J. Jr. (New Hampshire Univ., Durham (USA))

1982-04-01

Isotopic U-Pb studies of zircons collected from weathered metagreywackes of the Barama-Mazaruni Supergroup of northern Guyana, South America, demonstrate an age of origin of ca. 2250 Ma. This is the best estimate for the age of the associated metavolcanic rocks. Zircons from weathered gneiss of the Bartica complex, adjacent to the volcanic-sedimentary belts, yield a similar age. The contiguous greenstone-gneiss terrane of eastern Venezuela is also of similar age and comparable greenstone-gneiss terranes of eastern Suriname and French Guiana are probably also of this age. Continental crust formation of a style closely comparable to that of the Canadian Archean occurred on a very widespread scale in the Lower Proterozoic of the Guiana shield. The lead losses from the weathered zircons are comparable to those from zircons from fresh rock from the adjacent terrane of Venezuela, and the advantages of field concentration from numerous saprolite exposures warrant use of such material in future geochronological studies of the region.

New zircon (U-Th)/He and U/Pb eruption age for the Rockland tephra, western USA

Science.gov (United States)

Coble, Matthew A.; Burgess, Seth D.; Klemetti, Erik W.

2017-09-01

Eruption ages of a number of prominent Quaternary volcanic deposits remain inaccurately and/or imprecisely constrained, despite their importance as regional stratigraphic markers in paleo-environment reconstruction and as evidence of climate-altering eruptions. Accurately dating volcanic deposits presents challenging analytical considerations, including poor radiogenic yield, scarcity of datable minerals, and contamination of crystal populations by magma, eruption, and transport processes. One prominent example is the Rockland tephra, which erupted from the Lassen Volcanic Center in the southern Cascade arc. Despite a range in published eruption ages from 0.40 to 0.63 Ma, the Rockland tephra is extensively used as a marker bed across the western United States. To more accurately and precisely constrain the age of the Rockland tephra-producing eruption, we report U/Pb crystallization dates from the outermost ∼2 μm of zircon crystal faces (surfaces) using secondary ion mass spectrometry (SIMS). Our new weighted mean 238U/206Pb age for Rockland tephra zircon surfaces is 0.598 ± 0.013 Ma (2σ) and MSWD = 1.11 (mean square weighted deviation). As an independent test of the accuracy of this age, we obtained new (U-Th)/He dates from individual zircon grains from the Rockland tephra, which yielded a weighted mean age of 0.599 ± 0.012 Ma (2σ, MSWD = 5.13). We also obtained a (U-Th)/He age of 0.628 ± 0.014 Ma (MSWD = 1.19) for the Lava Creek Tuff member B, which was analyzed as a secondary standard to test the accuracy of the (U-Th)/He technique for Quaternary tephras, and to evaluate assumptions made in the model-age calculation. Concordance of new U/Pb and (U-Th)/He zircon ages reinforces the accuracy of our preferred Rockland tephra eruption age, and confirms that zircon surface dates sample zircon growth up to the time of eruption. We demonstrate the broad applicability of coupled U/Pb zircon-surface and single-grain zircon (U-Th)/He geochronology to accurate

Radioactivity in the zircon industry

International Nuclear Information System (INIS)

Selby, J.H.

2002-01-01

In a presentation from the Zircon Industry, it was shown that zircon sand contains significant concentrations of uranium, 3,500 to 4,500 Bq/kg, and thorium, 400 to 600 Bq/kg. Deposits mainly occur in South Africa, Australia, India and the USA. The mining is done by dredging or by just shoveling the sand onto trucks. The separation could be done by dry or wet concentration. Also the milling could be by dry or wet processes. The dry process has the highest risk of dust generation. The maximum potential annual dose for the milling process has been assessed to be about 5mSv. Measurements from South Africa and Australia indicate lower doses, 0.2 to 1 mSv/y

Lunar Dust and Lunar Simulant Activation, Monitoring, Solution and Cellular Toxicity Properties

Science.gov (United States)

Wallace, William; Jeevarajan, A. S.

2009-01-01

During the Apollo missions, many undesirable situations were encountered that must be mitigated prior to returning humans to the moon. Lunar dust (that part of the lunar regolith less than 20 microns in diameter) was found to produce several problems with mechanical equipment and could have conceivably produced harmful physiological effects for the astronauts. For instance, the abrasive nature of the dust was found to cause malfunctions of various joints and seals of the spacecraft and suits. Additionally, though efforts were made to exclude lunar dust from the cabin of the lunar module, a significant amount of material nonetheless found its way inside. With the loss of gravity correlated with ascent from the lunar surface, much of the finer fraction of this dust began to float and was inhaled by the astronauts. The short visits tothe Moon during Apollo lessened exposure to the dust, but the plan for future lunar stays of up to six months demands that methods be developed to minimize the risk of dust inhalation. The guidelines for what constitutes "safe" exposure will guide the development of engineering controls aimed at preventing the presence of dust in the lunar habitat. This work has shown the effects of grinding on the activation level of lunar dust, the changes in dissolution properties of lunar simulant, and the production of cytokines by cellular systems. Grinding of lunar dust leads to the production of radicals in solution and increased dissolution of lunar simulant in buffers of different pH. Additionally, ground lunar simulant has been shown to promote the production of IL-6 and IL-8, pro-inflammatory cytokines, by alveolar epithelial cells. These results provide evidence of the need for further studies on these materials prior to returning to the lunar surface.

Lunar horticulture.

Science.gov (United States)

Walkinshaw, C. H.

1971-01-01

Discussion of the role that lunar horticulture may fulfill in helping establish the life support system of an earth-independent lunar colony. Such a system is expected to be a hybrid between systems which depend on lunar horticulture and those which depend upon the chemical reclamation of metabolic waste and its resynthesis into nutrients and water. The feasibility of this approach has been established at several laboratories. Plants grow well under reduced pressures and with oxygen concentrations of less than 1% of the total pressure. The carbon dioxide collected from the lunar base personnel should provide sufficient gas pressure (approx. 100 mm Hg) for growing the plants.

Cis-Lunar Base Camp

Science.gov (United States)

Merrill, Raymond G.; Goodliff, Kandyce E.; Mazanek, Daniel D.; Reeves, John D., Jr.

2012-01-01

Historically, when mounting expeditions into uncharted territories, explorers have established strategically positioned base camps to pre-position required equipment and consumables. These base camps are secure, safe positions from which expeditions can depart when conditions are favorable, at which technology and operations can be tested and validated, and facilitate timely access to more robust facilities in the event of an emergency. For human exploration missions into deep space, cis-lunar space is well suited to serve as such a base camp. The outer regions of cis-lunar space, such as the Earth-Moon Lagrange points, lie near the edge of Earth s gravity well, allowing equipment and consumables to be aggregated with easy access to deep space and to the lunar surface, as well as more distant destinations, such as near-Earth Asteroids (NEAs) and Mars and its moons. Several approaches to utilizing a cis-lunar base camp for sustainable human exploration, as well as some possible future applications are identified. The primary objective of the analysis presented in this paper is to identify options, show the macro trends, and provide information that can be used as a basis for more detailed mission development. Compared within are the high-level performance and cost of 15 preliminary cis-lunar exploration campaigns that establish the capability to conduct crewed missions of up to one year in duration, and then aggregate mass in cis-lunar space to facilitate an expedition from Cis-Lunar Base Camp. Launch vehicles, chemical propulsion stages, and electric propulsion stages are discussed and parametric sizing values are used to create architectures of in-space transportation elements that extend the existing in-space supply chain to cis-lunar space. The transportation options to cis-lunar space assessed vary in efficiency by almost 50%; from 0.16 to 0.68 kg of cargo in cis-lunar space for every kilogram of mass in Low Earth Orbit (LEO). For the 15 cases, 5-year campaign

Application of automation and robotics to lunar surface human exploration operations

Science.gov (United States)

Woodcock, Gordon R.; Sherwood, Brent; Buddington, Patricia A.; Bares, Leona C.; Folsom, Rolfe; Mah, Robert; Lousma, Jack

1990-01-01

Major results of a study applying automation and robotics to lunar surface base buildup and operations concepts are reported. The study developed a reference base scenario with specific goals, equipment concepts, robot concepts, activity schedules and buildup manifests. It examined crew roles, contingency cases and system reliability, and proposed a set of technologies appropriate and necessary for effective lunar operations. This paper refers readers to four companion papers for quantitative details where appropriate.

Laser-Assisted Atom Probe Tomography of Deformed Minerals: A Zircon Case Study.

Science.gov (United States)

La Fontaine, Alexandre; Piazolo, Sandra; Trimby, Patrick; Yang, Limei; Cairney, Julie M

2017-04-01

The application of atom probe tomography to the study of minerals is a rapidly growing area. Picosecond-pulsed, ultraviolet laser (UV-355 nm) assisted atom probe tomography has been used to analyze trace element mobility within dislocations and low-angle boundaries in plastically deformed specimens of the nonconductive mineral zircon (ZrSiO4), a key material to date the earth's geological events. Here we discuss important experimental aspects inherent in the atom probe tomography investigation of this important mineral, providing insights into the challenges in atom probe tomography characterization of minerals as a whole. We studied the influence of atom probe tomography analysis parameters on features of the mass spectra, such as the thermal tail, as well as the overall data quality. Three zircon samples with different uranium and lead content were analyzed, and particular attention was paid to ion identification in the mass spectra and detection limits of the key trace elements, lead and uranium. We also discuss the correlative use of electron backscattered diffraction in a scanning electron microscope to map the deformation in the zircon grains, and the combined use of transmission Kikuchi diffraction and focused ion beam sample preparation to assist preparation of the final atom probe tip.

Benefits of Using a Mars Forward Strategy for Lunar Surface Systems

Science.gov (United States)

Mulqueen, Jack; Griffin, Brand; Smitherman, David; Maples, Dauphne

2009-01-01

This paper identifies potential risk reduction, cost savings and programmatic procurement benefits of a Mars Forward Lunar Surface System architecture that provides commonality or evolutionary development paths for lunar surface system elements applicable to Mars surface systems. The objective of this paper is to identify the potential benefits for incorporating a Mars Forward development strategy into the planned Project Constellation Lunar Surface System Architecture. The benefits include cost savings, technology readiness, and design validation of systems that would be applicable to lunar and Mars surface systems. The paper presents a survey of previous lunar and Mars surface systems design concepts and provides an assessment of previous conclusions concerning those systems in light of the current Project Constellation Exploration Architectures. The operational requirements for current Project Constellation lunar and Mars surface system elements are compared and evaluated to identify the potential risk reduction strategies that build on lunar surface systems to reduce the technical and programmatic risks for Mars exploration. Risk reduction for rapidly evolving technologies is achieved through systematic evolution of technologies and components based on Moore's Law superimposed on the typical NASA systems engineering project development "V-cycle" described in NASA NPR 7120.5. Risk reduction for established or slowly evolving technologies is achieved through a process called the Mars-Ready Platform strategy in which incremental improvements lead from the initial lunar surface system components to Mars-Ready technologies. The potential programmatic benefits of the Mars Forward strategy are provided in terms of the transition from the lunar exploration campaign to the Mars exploration campaign. By utilizing a sequential combined procurement strategy for lunar and Mars exploration surface systems, the overall budget wedges for exploration systems are reduced and the

Mass-spectrometric mining of Hadean zircons by automated SHRIMP multi-collector and single-collector U/Pb zircon age dating: The first 100,000 grains

Science.gov (United States)

Holden, Peter; Lanc, Peter; Ireland, Trevor R.; Harrison, T. Mark; Foster, John J.; Bruce, Zane

2009-09-01

The identification and retrieval of a large population of ancient zircons (>4 Ga; Hadean) is of utmost priority if models of the early evolution of Earth are to be rigorously tested. We have developed a rapid and accurate U-Pb zircon age determination protocol utilizing a fully automated multi-collector ion microprobe, the ANU SHRIMP II, to screen and date these zircons. Unattended data acquisition relies on the calibration of a digitized sample map to the Sensitive High Resolution Ion MicroProbe (SHRIMP) sample-stage co-ordinate system. High precision positioning of individual grains can be produced through optical image processing of a specified mount location. The focal position of the mount can be optimized through a correlation between secondary-ion steering and the spot position on the target. For the Hadean zircon project, sample mounts are photographed and sample locations (normally grain centers) are determined off-line. The sample is loaded, reference points calibrated, and the target positions are then visited sequentially. In SHRIMP II multiple-collector mode, zircons are initially screened (ca. 5 s data acquisition) through their 204Pb corrected 207Pb/206Pb ratio; suitable candidates are then analyzed in a longer routine to obtain better measurement statistics, U/Pb, and concentration data. In SHRIMP I and SHRIMP RG, we have incorporated the automated analysis protocol to single-collector measurements. These routines have been used to analyze over 100,000 zircons from the Jack Hills quartzite. Of these, ca. 7%, have an age greater than 3.8 Ga, the oldest grain being 4372 +/- 6 Ma (2[sigma]), and this age is part of a group of analyses around 4350 Ma which we interpret as the age when continental crust first began to coalesce in this region. In multi-collector mode, the analytical time taken for a single mount with 400 zircons is approximately 6 h; whereas in single-collector mode, the analytical time is ca. 17 h. With this productivity, we can produce

Lunar transportation system

Science.gov (United States)

1993-07-01

The University Space Research Association (USRA) requested the University of Minnesota Spacecraft Design Team to design a lunar transportation infrastructure. This task was a year long design effort culminating in a complete conceptual design and presentation at Johnson Space Center. The mission objective of the design group was to design a system of vehicles to bring a habitation module, cargo, and crew to the lunar surface from LEO and return either or both crew and cargo safely to LEO while emphasizing component commonality, reusability, and cost effectiveness. During the course of the design, the lunar transportation system (LTS) has taken on many forms. The final design of the system is composed of two vehicles, a lunar transfer vehicle (LTV) and a lunar excursion vehicle (LEV). The LTV serves as an efficient orbital transfer vehicle between the earth and the moon while the LEV carries crew and cargo to the lunar surface. Presented in the report are the mission analysis, systems layout, orbital mechanics, propulsion systems, structural and thermal analysis, and crew systems, avionics, and power systems for this lunar transportation concept.

Petrology of lunar rocks and implication to lunar evolution

Science.gov (United States)

Ridley, W. I.

1976-01-01

Recent advances in lunar petrology, based on studies of lunar rock samples available through the Apollo program, are reviewed. Samples of bedrock from both maria and terra have been collected where micrometeorite impact penetrated the regolith and brought bedrock to the surface, but no in situ cores have been taken. Lunar petrogenesis and lunar thermal history supported by studies of the rock sample are discussed and a tentative evolutionary scenario is constructed. Mare basalts, terra assemblages of breccias, soils, rocks, and regolith are subjected to elemental analysis, mineralogical analysis, trace content analysis, with studies of texture, ages and isotopic composition. Probable sources of mare basalts are indicated.

High-precision ID-TIMS zircon U-Pb geochronology using new 1013 Ohm resistors

Science.gov (United States)

Von Quadt, A.; Buret, Y.; Large, S.; Peytcheva, I.; Trinquier, A.; Wotzlaw, J. F.

2015-12-01

Faraday cups equipped with high gain amplifiers provide a means to measure small ion beams in static mode without the limited linear range of ion counting systems. We tested the application of newly available 1013 Ohm resistors to ID-TIMS zircon U-Pb geochronology using a range of natural and synthetic reference materials. The TritonPlus-RPQ at the Institute of Geochemistry and Petrology, ETH Zurich, is equipped with five new 1013 Ohm resistors and one MasCom secondary electron multiplier, allowing to measure the 202-204-205-206-207-208Pb masses in static mode. U is measured subsequently as U-oxide (265-267-270UO2) during a second step, also in static Faraday mode. The gain calibration of the 1013 Ohm resistors was performed using the procedure of Trinquier (2014), with 144Nd-146Nd being measured using 1011 Ohm resistor and 142-143-145-148-150Nd being measured using 1013 Ohm resitors (Trinquier, 2014; Koornneef et al., 2014). Standard deviations of the noise in all five new 1013 Ohm resistors are lower than 5.0 x 10-6 over a 6 month period, with no shift occurring over this time interval. This new detector set-up was tested by analyzing natural zircon standard materials and synthetic U/Pb solutions (www.earthime.org), ranging in age from ~2 Ma to ~600 Ma. All natural zircon standards were chemically abraded (Mattinson, 2005) and all samples were spiked with the ET2535 tracer solution. U-Pb dates obtained using the static measurement routine are compared to measurements employing dynamic peak jumping routines on the MasCom multiplier. This study illustrates the benefits and current limitations of using high gain amplifiers to measure small ion beams for zircon U-Pb geochronology compared to conventional dynamic ion counting techniques. Mattinson, J.M. (2005) Chemical Geology 220:47-66; Trinquier, A. (2014) Application Note 30281; Koornneef, J. et al (2014) Analytica Chimica Acta 819:49-55.

Lunar Topography: Results from the Lunar Orbiter Laser Altimeter

Science.gov (United States)

Neumann, Gregory; Smith, David E.; Zuber, Maria T.; Mazarico, Erwan

2012-01-01

The Lunar Orbiter Laser Altimeter (LOLA) onboard the Lunar Reconnaissance Orbiter (LRO) has been operating nearly continuously since July 2009, accumulating over 6 billion measurements from more than 2 billion in-orbit laser shots. LRO's near-polar orbit results in very high data density in the immediate vicinity of the lunar poles, with full coverage at the equator from more than 12000 orbital tracks averaging less than 1 km in spacing at the equator. LRO has obtained a global geodetic model of the lunar topography with 50-meter horizontal and 1-m radial accuracy in a lunar center-of-mass coordinate system, with profiles of topography at 20-m horizontal resolution, and 0.1-m vertical precision. LOLA also provides measurements of reflectivity and surface roughness down to its 5-m laser spot size. With these data LOLA has measured the shape of all lunar craters 20 km and larger. In the proposed extended mission commencing late in 2012, LOLA will concentrate observations in the Southern Hemisphere, improving the density of the polar coverage to nearly 10-m pixel resolution and accuracy to better than 20 m total position error. Uses for these data include mission planning and targeting, illumination studies, geodetic control of images, as well as lunar geology and geophysics. Further improvements in geodetic accuracy are anticipated from the use of re ned gravity fields after the successful completion of the Gravity Recovery and Interior Laboratory (GRAIL) mission in 2012.

Do Hf isotopes in magmatic zircons represent those of their host rocks?

Science.gov (United States)

Wang, Di; Wang, Xiao-Lei; Cai, Yue; Goldstein, Steven L.; Yang, Tao

2018-04-01

Lu-Hf isotopic system in zircon is a powerful and widely used geochemical tracer in studying petrogenesis of magmatic rocks and crustal evolution, assuming that zircon Hf isotopes can represent initial Hf isotopes of their parental whole rock. However, this assumption may not always be valid. Disequilibrium partial melting of continental crust would preferentially melt out non-zircon minerals with high time-integrated Lu/Hf ratios and generate partial melts with Hf isotope compositions that are more radiogenic than those of its magma source. Dissolution experiments (with hotplate, bomb and sintering procedures) of zircon-bearing samples demonstrate this disequilibrium effect where partial dissolution yielded variable and more radiogenic Hf isotope compositions than fully dissolved samples. A case study from the Neoproterozoic Jiuling batholith in southern China shows that about half of the investigated samples show decoupled Hf isotopes between zircons and the bulk rocks. This decoupling could reflect complex and prolonged magmatic processes, such as crustal assimilation, magma mixing, and disequilibrium melting, which are consistent with the wide temperature spectrum from ∼630 °C to ∼900 °C by Ti-in-zircon thermometer. We suggest that magmatic zircons may only record the Hf isotopic composition of their surrounding melt during crystallization and it is uncertain whether their Hf isotopic compositions can represent the primary Hf isotopic compositions of the bulk magmas. In this regard, using zircon Hf isotopic compositions to trace crustal evolution may be biased since most of these could be originally from disequilibrium partial melts.

Lunar e-Library: A Research Tool Focused on the Lunar Environment

Science.gov (United States)

McMahan, Tracy A.; Shea, Charlotte A.; Finckenor, Miria; Ferguson, Dale

2007-01-01

As NASA plans and implements the Vision for Space Exploration, managers, engineers, and scientists need lunar environment information that is readily available and easily accessed. For this effort, lunar environment data was compiled from a variety of missions from Apollo to more recent remote sensing missions, such as Clementine. This valuable information comes not only in the form of measurements and images but also from the observations of astronauts who have visited the Moon and people who have designed spacecraft for lunar missions. To provide a research tool that makes the voluminous lunar data more accessible, the Space Environments and Effects (SEE) Program, managed at NASA's Marshall Space Flight Center (MSFC) in Huntsville, AL, organized the data into a DVD knowledgebase: the Lunar e-Library. This searchable collection of 1100 electronic (.PDF) documents and abstracts makes it easy to find critical technical data and lessons learned from past lunar missions and exploration studies. The SEE Program began distributing the Lunar e-Library DVD in 2006. This paper describes the Lunar e-Library development process (including a description of the databases and resources used to acquire the documents) and the contents of the DVD product, demonstrates its usefulness with focused searches, and provides information on how to obtain this free resource.

What can zircon ages from the Jack Hills detrital zircon suite really tell us about Hadean geodynamics?

Science.gov (United States)

Whitehouse, Martin; Nemchin, Alexander

2015-04-01

As the only direct sample of the Hadean Earth, detrital zircon grains from the Jack Hills, Western Australia, have been the subject of intense investigation over the almost three decades since their discovery. A wide variety of geochemical and isotopic analyses of these grains, as well as their mineral inclusions, have been used variously to support two fundamentally different models for Hadean geodynamics: (i) Some form of (not necessarily modern-style) plate recycling generating felsic (continental-type?) crust at the boundaries [1, 2], or conversely (ii) the persistence of a long-lived, stagnant basaltic lid within which magmatism occurred as a result of internal temperature perturbations and/or impacts [3, 4], a model also generally consistent with a wide range of observations from post-Hadean geochemical reservoirs. Despite the considerable time and resources expended, the majority of these studies uncritically accept the individual U-Pb zircon ages, even though their veracity is key to many of the interpretations [5, 6]. We report here the results of an in-depth evaluation of all published (and new) U-Pb ages from the Jack Hills zircon suite in order to define age populations that can be used with a high degree of confidence in geodynamic interpretations. A notable problem in the interpretation of U-Pb data from ancient zircon grains (including those as young as the Neoarchean) is that disturbance of the systematics even several 100 Ma after crystallization causes data to spread along the concordia curve without becoming discernably discordant within the relatively large error bounds associated with U/Pb ages from in situ dating methods (e.g. SIMS). While 207Pb/206Pb ages are typically more precise, individually they provide no means to detect Pb-loss-induced younging. However, if two or preferably more analyses have been made in the same zircon growth zone, a reasonable evaluation of the possibility of Pb-loss can be made. In the available Jack Hills zircon

Lunar lander stage requirements based on the Civil Needs Data Base

Science.gov (United States)

Mulqueen, John A.

1992-01-01

This paper examines the lunar lander stages that will be necessary for the future exploration and development of the Moon. Lunar lander stage sizing is discussed based on the projected lunar payloads listed in the Civil Needs Data Base. Factors that will influence the lander stage design are identified and discussed. Some of these factors are (1) lunar orbiting and lunar surface lander bases; (2) implications of direct landing trajectories and landing from a parking orbit; (3) implications of landing site and parking orbit; (4) implications of landing site and parking orbit selection; (5) the use of expendable and reusable lander stages; and (6) the descent/ascent trajectories. Data relating the lunar lander stage design requirements to each of the above factors and others are presented in parametric form. These data will provide useful design data that will be applicable to future mission model modifications and design studies.

Integrated Lunar Information Architecture for Decision Support Version 3.0 (ILIADS 3.0)

Science.gov (United States)

Talabac, Stephen; Ames, Troy; Blank, Karin; Hostetter, Carl; Brandt, Matthew

2013-01-01

ILIADS 3.0 provides the data management capabilities to access CxP-vetted lunar data sets from the LMMP-provided Data Portal and the LMMP-provided On-Moon lunar data product server. (LMMP stands for Lunar Mapping and Modeling Project.) It also provides specific quantitative analysis functions to meet the stated LMMP Level 3 functional and performance requirements specifications that were approved by the CxP. The purpose of ILIADS 3.0 is to provide an integrated, rich client lunar GIS software application

Zircons and fluids: An experimental investigation with applications for radioactive waste disposal: Progress report, June 1, 1988--March 1, 1989

International Nuclear Information System (INIS)

Sinha, A.K.; Hewitt, D.A.; Ribbe, P.H.; Wayne, D.

1989-01-01

Experimental hydrothermal investigations of natural zircons have shown significant variations in loss of uranium. The percent loss is related to the composition of the fluid used in the experimental changes, rather than pressure and temperature alone. Development of microfractures provide an increase in surface area, and may be critical in developing adsorption models for actinides associated with radioactive waste storage. Zircons are being synthesized with various elemental substitution schemes prior to hydrothermal stability tests. 55 refs., 3 figs., 6 tabs

Provenance of zircon of the lowermost sedimentary cover, Estonia, East-European Craton

Directory of Open Access Journals (Sweden)

Konsa, M.

1999-12-01

Full Text Available Bulk and accessory mineral composition of fresh and weathered crystalline rocks, and sedimentary deposits overlying the crystalline-sedimentary unconformity have been examined in core samples from 28 drill holes in Estonia. Before the Late Vendian to Early Cambrian regional subsidence and sedimentation, the region represented a flat plateau within the Svecofennian Domain. Palaeo-and Mesoproterozoic crystalline rocks, regardless their different initial mineral composition, subcrop under the Upper Vendian/Lower Cambrian sedimentary cover as usually intensely weathered rocks (saprolites composed of residual quartz, altered micas and prevailing clay minerals mainly of the kaolinite group. Thus, the bulk mineral composition of any basement crystalline rocks imparts no specific inherited rock-forming minerals into the covering sedimentary rocks. From the variety of accessory and opaque minerals of crystalline rocks, only zircon populations survived in saprolites. Crystalline rocks of different origin yield different zircons. Relationships between the zircon typology of the basement rocks having specific areas of distribution and the sedimentary rocks immediately overlying those crystalline rocks were the main subject of this study. The result is that siliciclastic sedimentary rocks covering weathered crystalline rocks only in places inherited zircons with typological features characteristic of specific basement areas. In northeastern Estonia, local lenses of the Oru Member (the earliest Upper Vendian sedimentary rocks in Estonia resembling the debris of weathered crystalline rocks yield accessory zircon which in a 1-2 m thick layer above the basement surface is similar to the zircons of the underlying weathering mantle of certain crystalline rocks. In the next unit, the Moldova Member, up to 43 m above the basement surface, a mixture of zircons resembling those of various local basement rocks has been found. Further upwards, in the Vendian and Lower

Chemical characterisation of zircon-cadmium sulfoselenide ceramic pigments

International Nuclear Information System (INIS)

Gazulla Barreda, M. F.; Rodrigo Edo, M.; Blasco Roca, E.; Orduna Cordero, M.

2013-01-01

The present paper addresses the development of a methodology that allows the complete chemical characterisation of zircon cadmium sulfoselenide ceramic pigments including minor and major elements. To develop the methodology, five zircon-cadmium sulfoselenide pigments with different hues were selected, studying the different measurement process steps, from sample preparation to the optimisation of the measurement of the different components of the pigments by spectroscopic techniques (WD-XRF and elemental analysis by combustion and IR detection). The chemical characterisation method developed was validated with synthetic standards prepared from the mixture of certified reference materials and pure oxides because no certified referenced materials of this type of pigments were commercially available. The developed method can be used for a complete chemical characterization of zircon-cadmium sulfoselenide ceramic pigments with a very low uncertainty for all the elements analysed. (Author)

SP-100 power system conceptual design for lunar base applications

International Nuclear Information System (INIS)

Mason, L.S.; Bloomfield, H.S.; Hainley, D.C.

1989-01-01

A conceptual design is presented for a nuclear power system utilizing an SP-100 reactor and multiple Stirling cycle engines for operation on the lunar surface. Based on the results of this study, it was concluded that this power plant could be a viable option for an evolutionary lunar base. The design concept consists of a 2500 kWt (kilowatt thermal) SP-100 reactor coupled to eight free-piston Stirling engines. Two of the engines are held in reserve to provide conversion system redundancy. The remaining engines operate at 91.7 percent of their rated capacity of 150 kWe. The design power level for this system is 825 kWe. Each engine has a pumped heat-rejection loop connected to a heat pipe radiator. Power system performance, sizing, layout configurations, shielding options, and transmission line characteristics are described. System components and integration options are compared for safety, high performance, low mass, and ease of assembly. The power plant was integrated with a proposed human lunar base concept to ensure mission compatibility. This study should be considered a preliminary investigation; further studies are planned to investigate the effect of different technologies on this baseline design

Mechanisms of strain accommodation in plastically-deformed zircon under simple shear deformation conditions during amphibolite-facies metamorphism

Science.gov (United States)

Kovaleva, Elizaveta; Klötzli, Urs; Wheeler, John; Habler, Gerlinde

2018-02-01

This study documents the strain accommodation mechanisms in zircon under amphibolite-facies metamorphic conditions in simple shear. Microstructural data from undeformed, fractured and crystal-plastically deformed zircon crystals are described in the context of the host shear zone, and evaluated in the light of zircon elastic anisotropy. Our work challenges the existing model of zircon evolution and shows previously undescribed rheological characteristics for this important accessory mineral. Crystal-plastically deformed zircon grains have axis oriented parallel to the foliation plane, with the majority of deformed grains having axis parallel to the lineation. Zircon accommodates strain by a network of stepped low-angle boundaries, formed by switching between tilt dislocations with the slip systems {010} and {110} and rotation axis [001], twist dislocations with the rotation axis [001], and tilt dislocations with the slip system {001} and rotation axis [010]. The slip system {110} is newly described for zircon. Most misorientation axes in plastically-deformed zircon grains are parallel to the XY plane of the sample and have [001] crystallographic direction. Such behaviour of strained zircon lattice is caused by elastic anisotropy that has a direct geometric control on the rheology, deformation mechanisms and dominant slip systems in zircon. Young's modulus and P wave velocity have highest values parallel to zircon [001] axis, indicating that zircon is elastically strong along this direction. Poisson ratio and Shear modulus demonstrate that zircon is also most resistant to shearing along [001]. Thus, [001] axis is the most common rotation axis in zircon. The described zircon behaviour is important to take into account during structural and geochronological investigations of (poly)metamorphic terrains. Geometry of dislocations in zircon may help reconstructing the geometry of the host shear zone(s), large-scale stresses in the crust, and, possibly, the timing of

Closed-Loop Pure Oxygen Static Feed Fuel Cell for Lunar Missions, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — In order to address the NASA lunar mission, DESC proposes to develop a proton exchange membrane (PEM) closed-loop pure oxygen fuel cell for application to lunar...

Investigating the Early Carbon Cycle Using Carbonaceous Inclusions and Dissolved Carbon in Detrital Zircon

Science.gov (United States)

Bell, E. A.; Boehnke, P.; Harrison, M.; Mao, W. L.

2015-12-01

Because the terrestrial rock record extends only to ~4 Ga and older materials thus far identified are limited to detrital zircons, information about volatile abundances and cycles on early Earth is limited. Carbon, for instance, plays an important role not only in the modern biosphere but also in deep recycling of materials between the crust and mantle. We are investigating the record of carbon abundance and origin in Hadean zircons from Jack Hills (W. Australia) using two main approaches. First, carbon may partition into the zircon structure at trace levels during crystallization from a magma, and better understanding of this partitioning behavior will allow for zircon's use as a monitor of magmatic carbon contents. We have measured carbon abundances in zircon from a variety of igneous rocks (gabbro; I-, A-, and S-type granitoids) via SIMS and found that although abundances are typically low (average raw 12C/30Si ~ 1x10-6), S-type granite zircons can reach a factor of 1000 over this background. Around 10% of Hadean zircons investigated show similar enrichments, consistent with other evidence for the derivation of many Jack Hills zircons from S-type granitoids and with the establishment of modern-level carbon abundances in the crust by ca. 4.2 Ga. Diamond and graphite inclusions reported in the Jack Hills zircons by previous studies proved to be contamination by polishing debris, leaving the true abundance of these materials in the population uncertain. On a second front, we have identified and investigated primary carbonaceous inclusions in these zircons. From a population of over 10,000 Jack Hills zircons, we identified one concordant 4.10±0.01 Ga zircon that contains primary graphite inclusions (so interpreted due to their enclosure in a crack-free zircon host as shown by transmission X-ray microscopy and their crystal habit). Their δ13CPDB of -24±5‰ is consistent with a biogenic origin and, in the absence of a likely inorganic mechanism to produce such a

Lunar Impact Basins: Stratigraphy, Sequence and Ages from Superposed Impact Crater Populations Measured from Lunar Orbiter Laser Altimeter (LOLA) Data

Science.gov (United States)

Fassett, C. I.; Head, J. W.; Kadish, S. J.; Mazarico, E.; Neumann, G. A.; Smith, D. E.; Zuber, M. T.

2012-01-01

Impact basin formation is a fundamental process in the evolution of the Moon and records the history of impactors in the early solar system. In order to assess the stratigraphy, sequence, and ages of impact basins and the impactor population as a function of time, we have used topography from the Lunar Orbiter Laser Altimeter (LOLA) on the Lunar Reconnaissance Orbiter (LRO) to measure the superposed impact crater size-frequency distributions for 30 lunar basins (D = 300 km). These data generally support the widely used Wilhelms sequence of lunar basins, although we find significantly higher densities of superposed craters on many lunar basins than derived by Wilhelms (50% higher densities). Our data also provide new insight into the timing of the transition between distinct crater populations characteristic of ancient and young lunar terrains. The transition from a lunar impact flux dominated by Population 1 to Population 2 occurred before the mid-Nectarian. This is before the end of the period of rapid cratering, and potentially before the end of the hypothesized Late Heavy Bombardment. LOLA-derived crater densities also suggest that many Pre-Nectarian basins, such as South Pole-Aitken, have been cratered to saturation equilibrium. Finally, both crater counts and stratigraphic observations based on LOLA data are applicable to specific basin stratigraphic problems of interest; for example, using these data, we suggest that Serenitatis is older than Nectaris, and Humboldtianum is younger than Crisium. Sample return missions to specific basins can anchor these measurements to a Pre-Imbrian absolute chronology.

The significance of zircon characteristic and its uranium concentration in evaluation of uranium metallogenetic prospect

International Nuclear Information System (INIS)

Li Yaosong; Zhu Jiechen; Xia Yuliang

1992-02-01

Zircon characteristic and its relation to uranium metallogenetic process have been studied on the basis of physics properties and chemical compositions. It is indicated that the colour of zircon crystal is related to uranium concentration; on the basis of method of zircon population type of Pupin J.P., the sectional plan of zircon population type has been designed, from which result that zircon population type of uranium-producing rock body is distributed mainly in second section, secondly in fourth section; U in zircon presents synchronous increase trend with Th, Hf and Ta; the uranium concentration in zircon from uranium-producing geologic body increases obviously and its rate of increase is more than that of the uranium concentration in rock; the period, in which uranium concentration in zircon is increased, is often related to better uranium-producing condition in that period of this area. 1785 data of the average uranium concentration in zircon have been counted and clear regularity has been obtained, namely the average uranium concentrations in zircon in rich uranium-producing area, rock, geologic body and metallogenetic zone are all higher than that in poor or no uranium-producing area, rock, geologic body and metallogenetic zone. This shows that the average uranium concentration in zircon within the region in fact reflects the primary uranium-bearing background in region and restricts directly follow-up possibility of uranium mineralization. On the basis of this, the uranium source conditions of known uranium metallogenetic zones and prospective provinces have been discussed, and the average uranium concentrations in zircon from magmatic rocks for 81 districts have been contrasted and graded, and some districts in which exploration will be worth doing further are put forward

Perspectives on Lunar Helium-3

Science.gov (United States)

Schmitt, Harrison H.

1999-01-01

return on investment, access to capital markets for a lunar 3He and terrestrial fusion power business will require a near-term return on investment, based on early applications of IEC fusion technology (10).

Contribution to the study of xenotime and zircon flotation

International Nuclear Information System (INIS)

Scorzeli, Isabella Bernstein; Torem, Mauricio Leonardo

1995-01-01

Flotation and electrokinetics behaviour have studied with xenotime (YPO 4 ) and zircon (Zr Si O 4 ) from a mixture of grains with 90% xenotime and 10% zircon, produced in cassiterite concentration process. Micro flotation and zeta potential have been also studied, by using oleic acid P.A. and DP1-6256 as collectors, and sodium metasillicate and Procol DA911 as modifier agents

Lunar magnetism

Science.gov (United States)

Hood, L. L.; Sonett, C. P.; Srnka, L. J.

1984-01-01

Aspects of lunar paleomagnetic and electromagnetic sounding results which appear inconsistent with the hypothesis that an ancient core dynamo was the dominant source of the observed crustal magnetism are discussed. Evidence is summarized involving a correlation between observed magnetic anomalies and ejecta blankets from impact events which indicates the possible importance of local mechanisms involving meteoroid impact processes in generating strong magnetic fields at the lunar surface. A reply is given to the latter argument which also presents recent evidence of a lunar iron core.

The Lunar Transit Telescope (LTT) - An early lunar-based science and engineering mission

Science.gov (United States)

Mcgraw, John T.

1992-01-01

The Sentinel, the soft-landed lunar telescope of the LTT project, is described. The Sentinel is a two-meter telescope with virtually no moving parts which accomplishes an imaging survey of the sky over almost five octaves of the electromagnetic spectrum from the ultraviolet into the infrared, with an angular resolution better than 0.1 arsec/pixel. The Sentinel will incorporate innovative techniques of interest for future lunar-based telescopes and will return significant engineering data which can be incorporated into future lunar missions. The discussion covers thermal mapping of the Sentinel, measurement of the cosmic ray flux, lunar dust, micrometeoroid flux, the lunar atmosphere, and lunar regolith stability and seismic activity.

Burn Delay Analysis of the Lunar Orbit Insertion for Korea Pathfinder Lunar Orbiter

Science.gov (United States)

Bae, Jonghee; Song, Young-Joo; Kim, Young-Rok; Kim, Bangyeop

2017-12-01

The first Korea lunar orbiter, Korea Pathfinder Lunar Orbiter (KPLO), has been in development since 2016. After launch, the KPLO will execute several maneuvers to enter into the lunar mission orbit, and will then perform lunar science missions for one year. Among these maneuvers, the lunar orbit insertion (LOI) is the most critical maneuver because the KPLO will experience an extreme velocity change in the presence of the Moon’s gravitational pull. However, the lunar orbiter may have a delayed LOI burn during operation due to hardware limitations and telemetry delays. This delayed burn could occur in different captured lunar orbits; in the worst case, the KPLO could fly away from the Moon. Therefore, in this study, the burn delay for the first LOI maneuver is analyzed to successfully enter the desired lunar orbit. Numerical simulations are performed to evaluate the difference between the desired and delayed lunar orbits due to a burn delay in the LOI maneuver. Based on this analysis, critical factors in the LOI maneuver, the periselene altitude and orbit period, are significantly changed and an additional delta-V in the second LOI maneuver is required as the delay burn interval increases to 10 min from the planned maneuver epoch.

A cislunar transportation system fuelled by lunar resources

Science.gov (United States)

Sowers, G. F.

2016-11-01

A transportation system for a self sustaining economy in cislunar space is discussed. The system is based on liquid oxygen (LO2), liquid hydrogen (LH2) propulsion whose fuels are derived from ice mined at the polar regions of the Moon. The elements of the transportation system consist of the Advanced Cryogenic Evolved Stage (ACES) and the XEUS lander, both being developed by United Launch Alliance (ULA). The main propulsion elements and structures are common between ACES and XEUS. Both stages are fully reusable with refueling of their LO2/LH2 propellants. Utilization of lunar sourced propellants has the potential to dramatically lower the cost of transportation within the cislunar environs. These lower costs dramatically lower the barriers to entry of a number of promising cislunar based activities including space solar power. One early application of the architecture is providing lunar sourced propellant to refuel ACES for traditional spacecraft deployment missions. The business case for this application provides an economic framework for a potential lunar water mining operation.

A short and long range study of mullite-zirconia-zircon composites

Energy Technology Data Exchange (ETDEWEB)

Rendtorff, Nicolas M.; Conconi, Maria S.; Aglietti, Esteban F. [Centro de Tecnologia de Recursos Minerales y Ceramica (CETMIC: CONICET-CIC) (Argentina); Chain, Cecilia Y.; Pasquevich, Alberto F. [Universidad Nacional de La Plata, Departamento de Fisica, IFLP, Facultad de Ciencias Exactas (Argentina); Rivas, Patricia C. [CONICET (Argentina); Martinez, Jorge A., E-mail: toto@fisica.unlp.edu.ar; Caracoche, Maria C. [Universidad Nacional de La Plata, Departamento de Fisica, IFLP, Facultad de Ciencias Exactas (Argentina)

2010-06-15

In the field of refractory materials, ceramics containing mullite-zirconia are the basis of those most used in the industry of glass and steel. It is known that the addition of zircon improves the behavior of the refractory used in service. Knowing that some mullite-zirconia composites properties as fracture strength and the elastic modulus E are associated with the material microstructure integrity, the eventual thermal decomposition of zircon into zirconia and silica could seriously alter the material elastic properties. In this paper the phase content of a series of mullite-zirconia-zircon (3Al{sub 2}O{sub 3}.2SiO{sub 2}-ZrO{sub 2}-ZrSiO{sub 4}) composites is determined at atomic level via perturbed angular correlations (PAC) and compared with that derived from the long range X-ray diffraction technique. PAC results on the as-prepared materials indicate that all nominal zircon is present and that it involves two types of nanoconfigurations, one of them describing aperiodic regions. The thermomechanical properties already reported for these materials could be related to the crystalline to aperiodic zircon concentrations ratio they exhibit.

Zircon (Hf, O isotopes) as melt indicator: Melt infiltration and abundant new zircon growth within melt rich layers of granulite-facies lenses versus solid-state recrystallization in hosting amphibolite-facies gneisses (central Erzgebirge, Bohemian Massif)

Science.gov (United States)

Tichomirowa, Marion; Whitehouse, Martin; Gerdes, Axel; Schulz, Bernhard

2018-03-01

In the central Erzgebirge within the Bohemian Massif, lenses of high pressure and ultrahigh pressure felsic granulites occur within meta-sedimentary and meta-igneous amphibolite-facies felsic rocks. In the felsic granulite, melt rich parts and restite form alternating layers, and were identified by petrology and bulk rock geochemistry. Mineral assemblages representing the peak P-T conditions were best preserved in melanocratic restite layers. In contrast, in the melt rich leucocratic layers, garnet and related HP minerals as kyanite are almost completely resorbed. Both layers display differences in accessory minerals: melanosomes have frequent and large monazite and Fe-Ti-minerals but lack xenotime and apatite; leucosomes have abundant apatite and xenotime while monazite is rare. Here we present a detailed petrographic study of zircon grains (abundance, size, morphology, inclusions) in granulite-facies and amphibolite-facies felsic gneisses, along with their oxygen and hafnium isotope compositions. Our data complement earlier Usbnd Pb ages and trace element data (REE, Y, Hf, U) on zircons from the same rocks (Tichomirowa et al., 2005). Our results show that the degree of melting determines the behaviour of zircon in different layers of the granulites and associated amphibolite-facies rocks. In restite layers of the granulite lenses, small, inherited, and resorbed zircon grains are preserved and new zircon formation is very limited. In contrast, new zircons abundantly grew in the melt rich leucocratic layers. In these layers, the new zircons (Usbnd Pb age, trace elements, Hf, O isotopes) best preserve the information on peak metamorphic conditions due to intense corrosion of other metamorphic minerals. The new zircons often contain inherited cores. Compared to cores, the new zircons and rims show similar or slightly lower Hf isotope values, slightly higher Hf model ages, and decreased oxygen isotope ratios. The isotope compositions (Hf, O) of new zircons indicate

Finding the "true" age: ways to read high-precision U-Pb zircon dates

Science.gov (United States)

Schaltegger, U.; Schoene, B.; Ovtcharova, M.; Sell, B. K.; Broderick, C. A.; Wotzlaw, J.

2011-12-01

Refined U-Pb dating techniques, applying an empirical chemical abrasion treatment prior to analysis [1], and using a precisely calibrated double isotope Pb, U EARTHTIME tracer solution, have led to an unprecedented two problems: (A) Post-crystallization Pb loss from decay damaged areas is considered to be mitigated by applying chemical abrasion techniques. The success of such treatment can, however, not be assumed a priori. The following examples demonstrate that youngest zircons are not biased by lead loss but represent close-to-youngest zircon growth: (i) coincidence of youngest zircon dates with co-magmatic titanite in tonalite; (ii) coincidence with statistically equivalent clusters of 206Pb/238U dates from zircon in residual melts of cogenetic mafic magmas; (iii) youngest zircons in ash beds of sedimentary sequences do not violate the stratigraphic superposition, whereas conventional statistical interpretation (mean or median values) does; (iv) results of published inter-laboratory cross-calibration tests using chemical abrasion on natural zircon crystals of the same sample arrive at the same 206Pb/238U result within case of single, significantly younger dates (>3 sigma), and are common in many pre-Triassic and hydrothermally altered rocks. (B) Pre-eruptive/pre-intrusive growth is found to be the main reason for scattered zircon ages in igneous rocks. Zircons crystallizing from the final magma batch are called autocrystic [3]. Autocrystic growth will happen in a moving or stagnant magma shortly before or after the rheological lockup by the crystals. Last crystallizing zircons in the interstitial melt may therefore postdate emplacement of the magma. The range of 206Pb/238U ages may yield a time frame for the cooling of a given magma batch, which could be added to quantitative thermal models of magma emplacement and cooling. Hf isotopes and trace elements of the dated zircon are used to trace the nature of the dated grains [4], specifically for identification of

Closer look at lunar volcanism

International Nuclear Information System (INIS)

Vaniman, D.T.; Heiken, G.; Taylor, G.J.

1984-01-01

Although the American Apollo and Soviet Luna missions concentrated on mare basalt samples, major questions remain about lunar volcanism. Lunar field work will be indispensable for resolving the scientific questions about ages, compositions, and eruption processes of lunar volcanism. From a utilitarian standpoint, a better knowledge of lunar volcanism will also yield profitable returns in lunar base construction (e.g., exploitation of rille or lava-tube structures) and in access to materials such as volatile elements, pure glass, or ilmenite for lunar industry

Production of electronic grade lunar silicon by disproportionation of silicon difluoride

Science.gov (United States)

Agosto, William N.

1993-01-01

Waldron has proposed to extract lunar silicon by sodium reduction of sodium fluorosilicate derived from reacting sodium fluoride with lunar silicon tetrafluoride. Silicon tetrafluoride is obtained by the action of hydrofluoric acid on lunar silicates. While these reactions are well understood, the resulting lunar silicon is not likely to meet electronic specifications of 5 nines purity. Dale and Margrave have shown that silicon difluoride can be obtained by the action of silicon tetrafluoride on elemental silicon at elevated temperatures (1100-1200 C) and low pressures (1-2 torr). The resulting silicon difluoride will then spontaneously disproportionate into hyperpure silicon and silicon tetrafluoride in vacuum at approximately 400 C. On its own merits, silicon difluoride polymerizes into a tough waxy solid in the temperature range from liquid nitrogen to about 100 C. It is the silicon analog of teflon. Silicon difluoride ignites in moist air but is stable under lunar surface conditions and may prove to be a valuable industrial material that is largely lunar derived for lunar surface applications. The most effective driver for lunar industrialization may be the prospects for industrial space solar power systems in orbit or on the moon that are built with lunar materials. Such systems would require large quantities of electronic grade silicon or compound semiconductors for photovoltaics and electronic controls. Since silicon is the most abundant semimetal in the silicate portion of any solar system rock (approximately 20 wt percent), lunar silicon production is bound to be an important process in such a solar power project. The lunar silicon extraction process is discussed.

Phosphorus Adsorption and Desorption Properties of Minnesota Basalt Lunar Simulant and Lunar Glass Simulant

Science.gov (United States)

Sutter, Brad; Hossner, Lloyd R.; Ming, Douglas W.

1996-01-01

Phosphorus (P) adsorption and desorption characteristics of Minnesota Basalt Lunar Simulant (MBLS) and Lunar Glass Simulant (LGS) were evaluated. Results of P interactions with lunar simulants indicated that mineral and glass components adsorbed between 50 and 70% of the applied P and that between 85 and 100% of the applied P was desorbed. The Extended Freundlich equation best described the adsorption data (r(sup 2) = 0.92), whereas the Raven/Hossner equation best described the desorption data ((r(sup 2) = 0.97). Kinetic desorption results indicated that MBLS and LGS released most of their P within 15 h. The expanded Elovich equation fit the data best at shorter times while t/Q(sub DT) equation had a better fit at longer times. These results indicate that P does not strongly adsorb to the two simulants and that any P that was adsorbed was readily desorbed in the presence of anion exchange resin. This work suggests that multiple small applications of P (10-20 mg P/kg) should be added to the simulants to ensure adequate solution P for plant uptake and efficient use of P fertilizer.

Refractory Materials of Zirconate. Part 2: Synthesis and some properties of strontium, zirconate, calcium zirconate and barium zirconate

Science.gov (United States)

Okubo, Tsutomo; Yonemochi, Osamu; Nakamura, Kazuo; Maeda, Minoru

1988-01-01

Chemical compounds SrZrO3, CaZrO3, and BaZrO3 were synthesized by solid reaction and arc fusion, and their properties examined. Results were as follows: (1) in the synthesis of CaZrO3 by solid reaction, ZrO2 solid solution with cubic form was produced, which then changed into CaZrO3; (2) the BaZrO3 was a cubic form and did not show any transformation, while SrZrO3 and CaZrO3 with an orthorhombic form transformed to a cubic form at high temperature; and (3) the solubility of BaZrO3 in acid and its vaporization rate at a high temperature were greater than those of zirconates.

View of the Lunar Module 'Orion' and Lunar Roving Vehicle during first EVA

Science.gov (United States)

1972-01-01

A view of the Lunar Module (LM) 'Orion' and Lunar Roving Vehicle (LRV), as photographed by Astronaut Charles M. Duke Jr., lunar module pilot, during the first Apollo 16 extravehicular activity (EVA-1) at the Descates landing site. Astronaut John W. Young, commander, can be seen directly behind the LRV. The lunar surface feature in the left background is Stone Mountain.

The composition of zircon in Variscan granites from Northern Portugal

Directory of Open Access Journals (Sweden)

Martins, H. C.B.

2014-12-01

Full Text Available A group of slightly peraluminous Variscan plutons in Northern Portugal were selected from the study of zircon composition. The selected plutons are: the Vila Pouca de Aguiar and the Lavadores-Madalena plutons with I-type affinities and the Vieira do Minho pluton, an l-S transitional type. Zircon occurs as euhedral to subhedral crystals and exhibit finely concentric oscillatory magmatic zoning mainly related to variations of Hf, Y, U and Th concentrations. Most zircon crystals show the dominant “xenotime” substitution. The zircon crystals have Zr/Hf ratio in the range of 21 to 52, with no significant differences between the different granites. These values are in the same range of other peraluminous granites and are in accordance with a crustal signature of zircon. Moreover, the range of Zr/Hf values in zircon crystals overlaps with that of crustal sources and consequently to the potential protoliths proposed in the genesis of the Vieira do Minho and the Vila Pouca de Aguiar plutons, namely meta-igneous crustal sources at different levels. Although zircon from the Lavadores-Madalena pluton has a compositional range similar to the other plutons, an origin by hibridisation has been proposed. However, similar zircon chemistry between this pluton and Vila Pouca de Aguiar and Vieira do Minho plutons could also suggest a similar crustal source.Se han seleccionado tres plutones graniticos variscos en el norte de Portugal para el estudio de la composición del circón. Los plutones son: Vila Pouca de Aguiar y Lavadores-Madalena con afinidad de tipo-I y el plutón de Vieira do Minho de tipo transicional I-S. Los circones se presentan en cristales euhédricos a subhédricos y tienen zonados magmáticos, concéntricos oscilatorios finos ligados principalmente a variaciones de las concentraciones del Hf, Y, U y Th. La mayoría de los cristales de circón muestran la sustitución dominante “xenotima”. Los zircones tienen relaciones Zr/Hf que var

Lunar Reconnaissance Orbiter Lunar Workshops for Educators, Year 1 Report

Science.gov (United States)

Jones, A. P.; Hsu, B. C.; Bleacher, L.; Shaner, A. J.; Dalton, H.

2011-12-01

This past summer, the Lunar Reconnaissance Orbiter (LRO) sponsored a series of weeklong professional development workshops designed to educate and inspire grade 6-12 science teachers: the Lunar Workshops for Educators. Participants learned about lunar science and exploration, gained tools to help address common student misconceptions about the Moon, heard some of the latest research results from LRO scientists, worked with LRO data, and learned how to bring these data to their students using hands-on activities aligned with grade 6-12 National Science Education Standards and Benchmarks. Where possible, the workshops also included tours of science facilities or field trips intended to help the teachers better understand mission operations or geologic processes relevant to the Moon. The workshops were very successful. Participants demonstrated an improved understanding of lunar science concepts in post-workshop assessments (as compared to identical pre-assessments) and a greater understanding of how to access and productively share data from LRO with their students and provide them with authentic research experiences. Participant feedback on workshop surveys was also enthusiastically positive. 5 additional Lunar Workshops for Educators will be held around the country in the summer of 2012. For more information and to register, visit http://lunar.gsfc.nasa.gov/lwe/index.html.

Application of Open Source Software by the Lunar Mapping and Modeling Project

Science.gov (United States)

Ramirez, P.; Goodale, C. E.; Bui, B.; Chang, G.; Kim, R. M.; Law, E.; Malhotra, S.; Rodriguez, L.; Sadaqathullah, S.; Mattmann, C. A.; Crichton, D. J.

2011-12-01

The Lunar Mapping and Modeling Project (LMMP), led by the Marshall Space Flight center (MSFC), is responsible for the development of an information system to support lunar exploration, decision analysis, and release of lunar data to the public. The data available through the lunar portal is predominantly derived from present lunar missions (e.g., the Lunar Reconnaissance Orbiter (LRO)) and from historical missions (e.g., Apollo). This project has created a gold source of data, models, and tools for lunar explorers to exercise and incorporate into their activities. At Jet Propulsion Laboratory (JPL), we focused on engineering and building the infrastructure to support cataloging, archiving, accessing, and delivery of lunar data. We decided to use a RESTful service-oriented architecture to enable us to abstract from the underlying technology choices and focus on interfaces to be used internally and externally. This decision allowed us to leverage several open source software components and integrate them by either writing a thin REST service layer or relying on the API they provided; the approach chosen was dependent on the targeted consumer of a given interface. We will discuss our varying experience using open source products; namely Apache OODT, Oracle Berkley DB XML, Apache Solr, and Oracle OpenSSO (now named OpenAM). Apache OODT, developed at NASA's Jet Propulsion Laboratory and recently migrated over to Apache, provided the means for ingestion and cataloguing of products within the infrastructure. Its usage was based upon team experience with the project and past benefit received on other projects internal and external to JPL. Berkeley DB XML, distributed by Oracle for both commercial and open source use, was the storage technology chosen for our metadata. This decision was in part based on our use Federal Geographic Data Committee (FGDC) Metadata, which is expressed in XML, and the desire to keep it in its native form and exploit other technologies built on

Zircons and fluids: An experimental investigation with applications for radioactive waste disposal

International Nuclear Information System (INIS)

Sinha, A.K.; Student, J.; Essex, R.

1991-01-01

The long-term stability of nuclear waste forms or barriers is related to changes in physical properties of the material induced through radiation damage and subsequent changes in solubility. Investigations conducted by us on natural zircons (ZrSiO 4 ) supports a positive correlation between level of alpha damage and fluid composition to enhanced levels of corrosion. New data are presented on the nature and rate of the solution process. We also present data on our continuing efforts to synthesize and characterize both pure ZrSiO 4 and doped with U, Th, Hf, Dy and P

Lithium in Jack Hills zircons: Evidence for extensive weathering of Earth's earliest crust

Science.gov (United States)

Ushikubo, Takayuki; Kita, Noriko T.; Cavosie, Aaron J.; Wilde, Simon A.; Rudnick, Roberta L.; Valley, John W.

2008-08-01

In situ Li analyses of 4348 to 3362 Ma detrital zircons from the Jack Hills, Western Australia by SIMS reveal that the Li abundances (typically 10 to 60 ppm) are commonly over 10,000 times higher than in zircons crystallized from mantle-derived magmas and in mantle-derived zircon megacrysts (typically Jack Hills zircons also have fractionated lithium isotope ratios ( δ7Li = - 19 to + 13‰) about five times more variable than those recorded in primitive ocean floor basalts (2 to 8‰), but similar to continental crust and its weathering products. Values of δ7Li below - 10‰ are found in zircons that formed as early as 4300 Ma. The high Li compositions indicate that primitive magmas were not the source of Jack Hills zircons and the fractionated values of δ7Li suggest that highly weathered regolith was sampled by these early Archean magmas. These new Li data provide evidence that the parent magmas of ancient zircons from Jack Hills incorporated materials from the surface of the Earth that interacted at low temperature with liquid water. These data support the hypothesis that continental-type crust and oceans existed by 4300 Ma, within 250 million years of the formation of Earth and the low values of δ7Li suggest that weathering was extensive in the early Archean.

Lunar-A

Indian Academy of Sciences (India)

penetrators will be transmitted to the earth station via the Lunar-A mother spacecraft orbiting at an altitude of about .... to save the power consumption of the Lunar-A penetrator .... and an origin-time versus tidal-phases correlation. (Toksoz et al ...

Lunar Sample Compendium

Science.gov (United States)

Meyer, Charles

2005-01-01

The purpose of the Lunar Sample Compendium will be to inform scientists, astronauts and the public about the various lunar samples that have been returned from the Moon. This Compendium will be organized rock by rock in the manor of a catalog, but will not be as comprehensive, nor as complete, as the various lunar sample catalogs that are available. Likewise, this Compendium will not duplicate the various excellent books and reviews on the subject of lunar samples (Cadogen 1981, Heiken et al. 1991, Papike et al. 1998, Warren 2003, Eugster 2003). However, it is thought that an online Compendium, such as this, will prove useful to scientists proposing to study individual lunar samples and should help provide backup information for lunar sample displays. This Compendium will allow easy access to the scientific literature by briefly summarizing the significant findings of each rock along with the documentation of where the detailed scientific data are to be found. In general, discussion and interpretation of the results is left to the formal reviews found in the scientific literature. An advantage of this Compendium will be that it can be updated, expanded and corrected as need be.

Lunar Circular Structure Classification from Chang 'e 2 High Resolution Lunar Images with Convolutional Neural Network

Science.gov (United States)

Zeng, X. G.; Liu, J. J.; Zuo, W.; Chen, W. L.; Liu, Y. X.

2018-04-01

Circular structures are widely distributed around the lunar surface. The most typical of them could be lunar impact crater, lunar dome, et.al. In this approach, we are trying to use the Convolutional Neural Network to classify the lunar circular structures from the lunar images.

New Insights on the Recrystallization and New Growth of Extensively Radiation-damaged Zircon

Science.gov (United States)

Hanchar, J. M.; Schmitz, M. D.; Wirth, R.

2012-12-01

Approximately 10 grams of cm-sized nearly metamict zircon crystals from the Saranac Prospect in the Bancroft District of Ontario were combined by breaking into small pieces and then ground under ethanol to a fine powder with an agate mortar and pestle in order to make enough homogeneously mixed material for multiple powder X-Ray and diffraction scans, high-resolution transmission electron microscopy (HR-TEM) measurements, and chemical abrasion isotope dilution thermal ionization mass spectrometry (CA-TIMS). While these large zircon crystals ground to a powder have a larger surface area and not in the same physical state (i.e., brown and metamict) as what is typically analyzed in single zircon CA-ID-TIMS U-Pb analysis (clear euhedral grains), the physical and chemical changes that occur during the heat treatment used in CA-TIMS are thought to be similar processes. Aliquots of the ground zircon powder were annealed in situ using a Pt furnace in a powder diffractometer during which time simultaneous powder diffraction patterns were acquired starting at 25°C, at elevated temperature (from 500°C to 1400°C) at selected time intervals, and then again at 25°C. The powder X-ray diffraction results indicate that below ~900°C the recrystallization of the zircon powder commences but is incomplete, even after 36 hours, with diffuse low intensity diffraction peaks. At 1150°C the zircon powder shows significant recrystallization. At 1150°C, the recrystallization is essentially complete in less than one hour. Before heating the zircon powder samples consisted of clear, transparent to brown, translucent, complexly zoned fragments. After heating at 900°C the zircon powder retained a smaller percentage of clear or brown complexly zoned fragments, while the majority of material had transformed to oscillatory or irregularly zoned, dominantly white opaque microcrystalline fragments. The clear fragments were hypothesized to be preexisting original crystalline zircon, the brown

Spacesuit Integrated Carbon Nanotube Dust Mitigation System for Lunar Exploration

Science.gov (United States)

Manyapu, Kavya Kamal

Lunar dust proved to be troublesome during the Apollo missions. The lunar dust comprises of fine particles, with electric charges imparted by solar winds and ultraviolet radiation. As such, it adheres readily, and easily penetrates through smallest crevices into mechanisms. During Apollo missions, the powdery dust substantially degraded the performance of spacesuits by abrading suit fabric and clogging seals. Dust also degraded other critical equipment such as rovers, thermal control and optical surfaces, solar arrays, and was thus shown to be a major issue for surface operations. Even inside the lunar module, Apollo astronauts were exposed to this dust when they removed their dust coated spacesuits. This historical evidence from the Apollo missions has compelled NASA to identify dust mitigation as a critical path. This important environmental challenge must be overcome prior to sending humans back to the lunar surface and potentially to other surfaces such as Mars and asteroids with dusty environments. Several concepts were successfully investigated by the international research community for preventing deposition of lunar dust on rigid surfaces (ex: solar cells, thermal radiators). However, applying these technologies for flexible surfaces and specifically to spacesuits has remained an open challenge, due to the complexity of the suit design, geometry, and dynamics. The research presented in this dissertation brings original contribution through the development and demonstration of the SPacesuit Integrated Carbon nanotube Dust Ejection/Removal (SPIcDER) system to protect spacesuits and other flexible surfaces from lunar dust. SPIcDER leverages the Electrodynamic Dust Shield (EDS) concept developed at NASA for use on solar cells. For the SPIcDER research, the EDS concept is customized for application on spacesuits and flexible surfaces utilizing novel materials and specialized design techniques. Furthermore, the performance of the active SPIcDER system is enhanced

Lunar Quest in Second Life, Lunar Exploration Island, Phase II

Science.gov (United States)

Ireton, F. M.; Day, B. H.; Mitchell, B.; Hsu, B. C.

2010-12-01

Linden Lab’s Second Life is a virtual 3D metaverse created by users. At any one time there may be 40,000-50,000 users on line. Users develop a persona and are seen on screen as a human figure or avatar. Avatars move through Second Life by walking, flying, or teleporting. Users form communities or groups of mutual interest such as music, computer graphics, and education. These groups communicate via e-mail, voice, and text within Second Life. Information on downloading the Second Life browser and joining can be found on the Second Life website: www.secondlife.com. This poster details Phase II in the development of Lunar Exploration Island (LEI) located in Second Life. Phase I LEI highlighted NASA’s LRO/LCROSS mission. Avatars enter LEI via teleportation arriving at a hall of flight housing interactive exhibits on the LRO/ LCROSS missions including full size models of the two spacecraft and launch vehicle. Storyboards with information about the missions interpret the exhibits while links to external websites provide further information on the mission, both spacecraft’s instrument suites, and related EPO. Other lunar related activities such as My Moon and NLSI EPO programs. A special exhibit was designed for International Observe the Moon Night activities with links to websites for further information. The sim includes several sites for meetings, a conference stage to host talks, and a screen for viewing NASATV coverage of mission and other televised events. In Phase II exhibits are updated to reflect on-going lunar exploration highlights, discoveries, and future missions. A new section of LEI has been developed to showcase NASA’s Lunar Quest program. A new exhibit hall with Lunar Quest information has been designed and is being populated with Lunar Quest information, spacecraft models (LADEE is in place) and kiosks. A two stage interactive demonstration illustrates lunar phases with static and 3-D stations. As NASA’s Lunar Quest program matures further

Laser-powered lunar base

International Nuclear Information System (INIS)

Costen, R.; Humes, D.H.; Walker, G.H.; Williams, M.D.; Deyoung, R.J.

1989-01-01

The objective was to compare a nuclear reactor-driven Sterling engine lunar base power source to a laser-to-electric converter with orbiting laser power station, each providing 1 MW of electricity to the lunar base. The comparison was made on the basis of total mass required in low-Earth-orbit for each system. This total mass includes transportation mass required to place systems in low-lunar orbit or on the lunar surface. The nuclear reactor with Sterling engines is considered the reference mission for lunar base power and is described first. The details of the laser-to-electric converter and mass are discussed. The next two solar-driven high-power laser concepts, the diode array laser or the iodine laser system, are discussed with associated masses in low-lunar-orbit. Finally, the payoff for laser-power beaming is summarized

Zircon ages in granulite facies rocks: decoupling from geochemistry above 850 °C?

Science.gov (United States)

Kunz, Barbara E.; Regis, Daniele; Engi, Martin

2018-03-01

Granulite facies rocks frequently show a large spread in their zircon ages, the interpretation of which raises questions: Has the isotopic system been disturbed? By what process(es) and conditions did the alteration occur? Can the dates be regarded as real ages, reflecting several growth episodes? Furthermore, under some circumstances of (ultra-)high-temperature metamorphism, decoupling of zircon U-Pb dates from their trace element geochemistry has been reported. Understanding these processes is crucial to help interpret such dates in the context of the P-T history. Our study presents evidence for decoupling in zircon from the highest grade metapelites (> 850 °C) taken along a continuous high-temperature metamorphic field gradient in the Ivrea Zone (NW Italy). These rocks represent a well-characterised segment of Permian lower continental crust with a protracted high-temperature history. Cathodoluminescence images reveal that zircons in the mid-amphibolite facies preserve mainly detrital cores with narrow overgrowths. In the upper amphibolite and granulite facies, preserved detrital cores decrease and metamorphic zircon increases in quantity. Across all samples we document a sequence of four rim generations based on textures. U-Pb dates, Th/U ratios and Ti-in-zircon concentrations show an essentially continuous evolution with increasing metamorphic grade, except in the samples from the granulite facies, which display significant scatter in age and chemistry. We associate the observed decoupling of zircon systematics in high-grade non-metamict zircon with disturbance processes related to differences in behaviour of non-formula elements (i.e. Pb, Th, U, Ti) at high-temperature conditions, notably differences in compatibility within the crystal structure.

Lower-Cost, Relocatable Lunar Polar Lander and Lunar Surface Sample Return Probes

Science.gov (United States)

Amato, G. Michael; Garvin, James B.; Burt, I. Joseph; Karpati, Gabe

2011-01-01

Key science and exploration objectives of lunar robotic precursor missions can be achieved with the Lunar Explorer (LEx) low-cost, robotic surface mission concept described herein. Selected elements of the LEx concept can also be used to create a lunar surface sample return mission that we have called Boomerang

Lunar Meteorites: A Global Geochemical Dataset

Science.gov (United States)

Zeigler, R. A.; Joy, K. H.; Arai, T.; Gross, J.; Korotev, R. L.; McCubbin, F. M.

2017-01-01

To date, the world's meteorite collections contain over 260 lunar meteorite stones representing at least 120 different lunar meteorites. Additionally, there are 20-30 as yet unnamed stones currently in the process of being classified. Collectively these lunar meteorites likely represent 40-50 distinct sampling locations from random locations on the Moon. Although the exact provenance of each individual lunar meteorite is unknown, collectively the lunar meteorites represent the best global average of the lunar crust. The Apollo sites are all within or near the Procellarum KREEP Terrane (PKT), thus lithologies from the PKT are overrepresented in the Apollo sample suite. Nearly all of the lithologies present in the Apollo sample suite are found within the lunar meteorites (high-Ti basalts are a notable exception), and the lunar meteorites contain several lithologies not present in the Apollo sample suite (e.g., magnesian anorthosite). This chapter will not be a sample-by-sample summary of each individual lunar meteorite. Rather, the chapter will summarize the different types of lunar meteorites and their relative abundances, comparing and contrasting the lunar meteorite sample suite with the Apollo sample suite. This chapter will act as one of the introductory chapters to the volume, introducing lunar samples in general and setting the stage for more detailed discussions in later more specialized chapters. The chapter will begin with a description of how lunar meteorites are ejected from the Moon, how deep samples are being excavated from, what the likely pairing relationships are among the lunar meteorite samples, and how the lunar meteorites can help to constrain the impactor flux in the inner solar system. There will be a discussion of the biases inherent to the lunar meteorite sample suite in terms of underrepresented lithologies or regions of the Moon, and an examination of the contamination and limitations of lunar meteorites due to terrestrial weathering. The

Strontium zirconate as silicon and aluminum scavenger in yttria stabilized zirconia

DEFF Research Database (Denmark)

Andersen, Thomas; Hansen, Karin Vels; Chorkendorff, Ib

2011-01-01

Here we report on strontium zirconate as a getter for silicon dioxide and aluminum oxide in yttria stabilized zirconia (YSZ) single crystals for cleaning purposes. YSZ single crystals were covered with strontium zirconate powder and heat treated at 1450°C in water vapor. After treatment the YSZ...... by transmission electron microscopy (TEM) the interface region between bump and YSZ single crystal bulk was examined. EDS showed a homogeneous distribution of silicon and aluminum through the cross section of a bump. The results suggest strontium zirconate as a good getter for silicon and aluminum from bulk...

U-Pb dating by zircon dissolution method using chemical abrasion

Energy Technology Data Exchange (ETDEWEB)

Takehara, Lucy, E-mail: lucytakehara@gmail.com.br [Servico Geologico do Brasil (CPRM), Brasilia, DF (Brazil); Chemale Junior, Farid [Universidade de Brasilia (UnB), Brasilia, DF (Brazil). Inst. de Geociencias. Lab. de Geocronologia; Hartmann, Leo A. [Universidade Federal do Rio Grande do Sul (UFRS), Porto Alegre, RS (Brazil). Inst. de Geociencias; Dussin, Ivo A.; Kawashita, Koji [Universidade de Sao Paulo (USP), SP, (Brazil). Centro de Pesquisa Geocronologicas

2012-06-15

Chemical abrasion was carried out on zircons grains of the Temora II standard for U-Pb dating prior to analyses using in situ Laser Ablation-Multi Collector Ion Coupled Plasma Mass Spectrometer (LA-ICPMS) followed by the Isotope Dissolution Thermal Ionization Mass Spectrometer (ID-TIMS) method. The proposed methodology was herein applied in order to reduce primarily the effects of secondary Pb loss, the presence of common lead and/or silicate impurities. Nine Temora II zircon grains were analyzed by the laser ablation method yielding an age of 418.3 +- 4.3 Ma. Zircon grains of a same population were separated for chemical abrasion before dissolution and mass spectrometry analyses. Six fractions of them were separated for isotope dissolution using {sup 235}U-{sup 205}Pb mixed spike after we have checked and assured the laboratory conditions of low blank values for total Pb of less than 2 pg/g. The obtained U-Pb zircon age by the ID-TIMS method was 415.7 +- 1.8 Ma (error 0.43 %) based on four successful determinations. The results are consistent with the published ages for the Temora diorite (Temora I - 416.75 +- 1.3 Ma; Temora II - 416.78 +- 0.33 Ma) and established as 416 +- 0.33 Ma. The technique is thus recommended for high precision U-Pb zircon analyses (error < 1 %), mainly for high resolution stratigraphic studies of Phanerozoic sequences. (author)

Paleozoic and Paleoproterozoic Zircon in Igneous Xenoliths Assimilated at Redoubt Volcano, Alaska

Science.gov (United States)

Bacon, C. R.; Vazquez, J. A.; Wooden, J. L.

2010-12-01

Historically active Redoubt Volcano is a basalt-to-dacite cone constructed upon the Jurassic-early Tertiary Alaska-Aleutian Range batholith. New SHRIMP-RG U-Pb age and trace-element concentration results for zircons from gabbroic xenoliths and crystal-rich andesitic mush from a late Pleistocene pyroclastic deposit indicate that ~310 Ma and ~1865 Ma igneous rocks underlie Redoubt at depth. Two gabbros have sharply terminated prismatic zircons that yield ages of ~310 Ma. Zircons from a crystal mush sample are overwhelmingly ~1865 Ma and appear rounded due to incomplete dissolution. Binary plots of element concentrations or ratios show clustering of data for ~310-Ma grains and markedly coherent trends for ~1865-Ma grains; e.g., ~310-Ma grains have higher Eu/Eu* than most of the ~1865-Ma grains, the majority of which form a narrow band of decreasing Eu/Eu* with increasing Hf content which suggests that ~1865-Ma zircons come from igneous source rocks. It is very unlikely that detrital zircons from a metasedimentary rock would have this level of homogeneity in age and composition. One gabbro contains abundant ~1865 Ma igneous zircons, ~300-310 Ma fluid-precipitated zircons characterized by very low U and Th concentrations and Th/U ratios, and uncommon ~100 Ma zircons. We propose that (1) ~310 Ma gabbro xenoliths from Redoubt Volcano belong to the same family of plutons dated by Aleinikoff et al. (USGS Circular 1016, 1988) and Gardner et al. (Geology, 1988) located ≥500 km to the northeast in basement rocks of the Wrangellia and Alexander terranes and (2) ~1865 Ma zircons are inherited from igneous rock, potentially from a continental fragment that possibly correlates with the Fort Simpson terrane or Great Bear magmatic zone of the Wopmay Orogen of northwestern Laurentia. Possibly, elements of these Paleoproterozoic terranes intersected the Paleozoic North American continental margin where they may have formed a component of the basement to the Wrangellia

Precision Lunar Laser Ranging For Lunar and Gravitational Science

Science.gov (United States)

Merkowitz, S. M.; Arnold, D.; Dabney, P. W.; Livas, J. C.; McGarry, J. F.; Neumann, G. A.; Zagwodzki, T. W.

2008-01-01

Laser ranging to retroreflector arrays placed on the lunar surface by the Apollo astronauts and the Soviet Lunar missions over the past 39 years have dramatically increased our understanding of gravitational physics along with Earth and Moon geophysics, geodesy, and dynamics. Significant advances in these areas will require placing modern retroreflectors and/or active laser ranging systems at new locations on the lunar surface. Ranging to new locations will enable better measurements of the lunar librations, aiding in our understanding of the interior structure of the moon. More precise range measurements will allow us to study effects that are too small to be observed by the current capabilities as well as enabling more stringent tests of Einstein's theory of General Relativity. Setting up retroreflectors was a key part of the Apollo missions so it is natural to ask if future lunar missions should include them as well. The Apollo retroreflectors are still being used today, and nearly 40 years of ranging data has been invaluable for scientific as well as other studies such as orbital dynamics. However, the available retroreflectors all lie within 26 degrees latitude of the equator, and the most useful ones within 24 degrees longitude of the sub-earth meridian. This clustering weakens their geometrical strength.

Lunar electrostatic effects and protection

International Nuclear Information System (INIS)

Sun, Yongwei; Yuan, Qingyun; Xiong, Jiuliang

2013-01-01

The space environment and features on the moon surface are factors in strong electrostatic electrification. Static electricity will be produced in upon friction between lunar soil and detectors or astronauts on the lunar surface. Lunar electrostatic environment effects from lunar exploration equipment are very harmful. Lunar dust with electrostatic charge may enter the equipment or even cover the instruments. It can affect the normal performance of moon detectors. Owing to the huge environmental differences between the moon and the earth, the electrostatic protection technology on the earth can not be applied. In this paper, we review the electrostatic characteristics of lunar dust, its effects on aerospace equipment and moon static elimination technologies. It was concluded that the effect of charged lunar dust on detectors and astronauts should be completely researched as soon as possible.

Contrasting Cu-Au and Sn-W Granite Metallogeny through the Zircon Geochemical and Isotopic Record

Science.gov (United States)

Gardiner, Nicholas; Hawkesworth, Chris; Robb, Laurence; Whitehouse, Martin; Roberts, Nick; Kirkland, Chris

2017-04-01

Magmatic genesis and evolution - mediated by geodynamic setting - exert a primary control on the propensity of granites to be metal fertile. A revolution in our understanding of these petrogenetic processes has been made through a range of mineral-based tools, most notably the common accessory mineral zircon. There is consequently considerable interest in whether the geochemical and isotopic compositions of zircon can be applied to metallogenic problems. The paired magmatic belts of Myanmar have broadly contrasting metallogenic affinities (Sn-W versus Cu-Au), and are interpreted to have formed on the accretionary margin of the subducting Neo-Tethys Ocean. They therefore present the opportunity to geochemically compare and contrast the zircon compositions in two end-member types of granite-hosted mineral deposits generated in collisional settings. We present an integrated zircon isotope (U-Pb, Lu-Hf, O) and trace element dataset that fingerprint: (a) source; (b) redox conditions; and (c) degree of fractionation. These variables all impact on magma fertility, and our key question to address is whether they can be reliably traced and calibrated within the Myanmar zircon record. Granitoid-hosted zircons from the I-type copper arc have juvenile ɛHf (+7 to +12) and mantle-like δ18O (5.3 ‰), whereas zircons from the S-type tin belt have low ɛHf (-7 to -13) and heavier δ18O (6.2-7.7 ‰). Plotting Hf versus U/Yb reaffirms that the tin belt magmas contain greater crustal contributions than the copper arc rocks. Links between whole rock Rb/Sr and zircon Eu/Eu* highlights that the latter can be used to monitor magma fractionation in systems that crystallize plagioclase (low Sr/Y). Ce/Ce* and Eu/Eu* in zircon are thus sensitive to redox and fractionation respectively, and can be used to evaluate the sensitivity of zircons to the metallogenic affinity of their host rocks. Tin contents that exceed the solubility limit are required in order to make a magmatic

NORM exposure to workers at a zircon sand processing factory

International Nuclear Information System (INIS)

Andersen, T.; Israelson, C.

2003-01-01

The National Institute of Radiation Hygiene (NIRH) has estimated doses to workers at a Danish zircon-processing industry. Calculations of internal doses were made after measuring dust concentrations in the working area and content of radium-226 and thorium-232 in the zircon sand. The total effective dose from internal and external irradiation was calculated to approximately 0,75 mSv/y. (orig.)

The Lunar Orbiter Laser Altimeter (LOLA) on NASA's Lunar Reconnaissance Orbiter (LRO) mission

Science.gov (United States)

Riris, H.; Cavanaugh, J.; Sun, X.; Liiva, P.; Rodriguez, M.; Neuman, G.

2017-11-01

The Lunar Orbiter Laser Altimeter (LOLA) instrument [1-3] on NASA's Lunar Reconnaissance Orbiter (LRO) mission, launched on June 18th, 2009, from Kennedy Space Center, Florida, will provide a precise global lunar topographic map using laser altimetry. LOLA will assist in the selection of landing sites on the Moon for future robotic and human exploration missions and will attempt to detect the presence of water ice on or near the surface, which is one of the objectives of NASA's Exploration Program. Our present knowledge of the topography of the Moon is inadequate for determining safe landing areas for NASA's future lunar exploration missions. Only those locations, surveyed by the Apollo missions, are known with enough detail. Knowledge of the position and characteristics of the topographic features on the scale of a lunar lander are crucial for selecting safe landing sites. Our present knowledge of the rest of the lunar surface is at approximately 1 km kilometer level and in many areas, such as the lunar far side, is on the order of many kilometers. LOLA aims to rectify that and provide a precise map of the lunar surface on both the far and near side of the moon. LOLA uses short (6 ns) pulses from a single laser through a Diffractive Optical Element (DOE) to produce a five-beam pattern that illuminates the lunar surface. For each beam, LOLA measures the time of flight (range), pulse spreading (surface roughness), and transmit/return energy (surface reflectance). LOLA will produce a high-resolution global topographic model and global geodetic framework that enables precise targeting, safe landing, and surface mobility to carry out exploratory activities. In addition, it will characterize the polar illumination environment, and image permanently shadowed regions of the lunar surface to identify possible locations of surface ice crystals in shadowed polar craters.

Point defects in crystalline zircon (zirconium silicate), ZrSiO4: electron paramagnetic resonance studies

Science.gov (United States)

Tennant, W. C.; Claridge, R. F. C.; Walsby, C. J.; Lees, N. S.

This article outlines the present state of knowledge of paramagnetic defects in crystalline zircon as obtained mainly, but not exclusively, from electron paramagnetic resonance (EPR) studies in crystalline zircon (zirconium silicate, ZrSiO4). The emphasis is on single-crystal studies where, in principle, unambiguous analysis is possible. Firstly, the crystallography of zircon is presented. Secondly, the relationships between available crystal-site symmetries and the symmetries of observed paramagnetic species in zircon, and how these observations lead to unambiguous assignments of point-group symmetries for particular paramagnetic species are detailed. Next, spin-Hamiltonian (SH) analysis is discussed with emphasis on the symmetry relationships that necessarily exist amongst the Laue classes of the crystal sites in zircon, the paramagnetic species occupying those sites and the SH itself. The final sections of the article then survey the results of EPR studies on zircon over the period 1960-2002.

Chemical characteristics of zircon from A-type granites and comparison to zircon of S-type granites

Czech Academy of Sciences Publication Activity Database

Breiter, Karel; Lamarão, C. N.; Krás Borges, R. M.; Dall'Agnol, R.

1192/195, April (2014), s. 208-225 ISSN 0024-4937 Institutional support: RVO:67985831 Keywords : zircon * A-type granites * S-type granites * Wiborg batholith * Brazil * Krušné hory/Erzgebirge Subject RIV: DD - Geochemistry Impact factor: 4.482, year: 2014

Heterogeneity in lunar anorthosite meteorites: implications for the lunar magma ocean model.

Science.gov (United States)

Russell, Sara S; Joy, Katherine H; Jeffries, Teresa E; Consolmagno, Guy J; Kearsley, Anton

2014-09-13

The lunar magma ocean model is a well-established theory of the early evolution of the Moon. By this model, the Moon was initially largely molten and the anorthositic crust that now covers much of the lunar surface directly crystallized from this enormous magma source. We are undertaking a study of the geochemical characteristics of anorthosites from lunar meteorites to test this model. Rare earth and other element abundances have been measured in situ in relict anorthosite clasts from two feldspathic lunar meteorites: Dhofar 908 and Dhofar 081. The rare earth elements were present in abundances of approximately 0.1 to approximately 10× chondritic (CI) abundance. Every plagioclase exhibited a positive Eu-anomaly, with Eu abundances of up to approximately 20×CI. Calculations of the melt in equilibrium with anorthite show that it apparently crystallized from a magma that was unfractionated with respect to rare earth elements and ranged in abundance from 8 to 80×CI. Comparisons of our data with other lunar meteorites and Apollo samples suggest that there is notable heterogeneity in the trace element abundances of lunar anorthosites, suggesting these samples did not all crystallize from a common magma source. Compositional and isotopic data from other authors also suggest that lunar anorthosites are chemically heterogeneous and have a wide range of ages. These observations may support other models of crust formation on the Moon or suggest that there are complexities in the lunar magma ocean scenario to allow for multiple generations of anorthosite formation. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

First lunar outpost

Science.gov (United States)

Andino, Aureo F.; Silva, Daniel; Ortiz, Nelson; Alvarez, Omar; Colon, Julio A.; Colon, Myrelle; Diaz, Alicia; Escobar, Xochiquetzal Y.; Garcia, Alberto; Gonzalez, Isabel C.

1992-01-01

Design and research efforts at the University of Puerto Rico have focused on the evaluation and refinement of the Habitability Criteria for a prolonged human presence in space during the last four years. Living quarters for a Mars mission and a third generation lunar base concept were proposed. This academic year, 1991-92, work on further refinement of the habitability criteria and design of partial gravity furniture was carried on. During the first semester, design alternatives for furniture necessary in a habitat design optimized for lunar and Martian environments were developed. Designs are based on recent research data from lunar and Mars gravity simulations, and current NASA standards. Artifacts will be submitted to NASA architects to be tested in KC-135 flights. Test findings will be submitted for incorporation in future updates to NASA habitat design standards. Second semester work was aimed at integrating these findings into the First Lunar Outpost (FLO), a mission scenario currently being considered by NASA. The mission consists of a manned return to the moon by crews of four astronauts for periods of 45 days. The major hardware components of the mission are as follows: (1) a Crew Module for the delivery of the crew and their supplies, and (2) the Habitat Module, which will arrive on the Moon unmanned. Our design efforts concentrated on this Habitat Module and on application of habitability criteria. Different geometries for the pressure vessel and their impact on the interior architecture were studied. Upon the selection of a geometry, a more detailed analysis of the interior design was performed, taking into consideration the reduced gravity, and the protection against radiation, micrometeorites, and the extreme temperature variation. A proposal for a FLO was submitted by the students, consisting essentially of a 24-feet (7.3 m.) by 35-feet (10.67 m) high vertical cylinder with work areas, crew quarters, galley, wardroom, leisure facilities, health

REE Partitioning in Lunar Minerals

Science.gov (United States)

Rapp, J. F.; Lapen, T. J.; Draper, D. S.

2015-01-01

Rare earth elements (REE) are an extremely useful tool in modeling lunar magmatic processes. Here we present the first experimentally derived plagioclase/melt partition coefficients in lunar compositions covering the entire suite of REE. Positive europium anomalies are ubiquitous in the plagioclase-rich rocks of the lunar highlands, and complementary negative Eu anomalies are found in most lunar basalts. These features are taken as evidence of a large-scale differentiation event, with crystallization of a global-scale lunar magma ocean (LMO) resulting in a plagioclase flotation crust and a mafic lunar interior from which mare basalts were subsequently derived. However, the extent of the Eu anomaly in lunar rocks is variable. Fagan and Neal [1] reported highly anorthitic plagioclase grains in lunar impact melt rock 60635,19 that displayed negative Eu anomalies as well as the more usual positive anomalies. Indeed some grains in the sample are reported to display both positive and negative anomalies. Judging from cathodoluminescence images, these anomalies do not appear to be associated with crystal overgrowths or zones.

Lunar resource base

Science.gov (United States)

Pulley, John; Wise, Todd K.; Roy, Claude; Richter, Phil

A lunar base that exploits local resources to enhance the productivity of a total SEI scenario is discussed. The goals were to emphasize lunar science and to land men on Mars in 2016 using significant amounts of lunar resources. It was assumed that propulsion was chemical and the surface power was non-nuclear. Three phases of the base build-up are outlined, the robotic emplacement of the first elements is detailed and a discussion of future options is included.

Phase quantification of mullite-zirconia and zircon commercial powders using PAC and XRD techniques

Energy Technology Data Exchange (ETDEWEB)

Rendtorff, Nicolas M.; Conconi, Maria S.; Aglietti, Esteban F. [Centro de Tecnologia de Recursos Minerales y Ceramica (CETMIC: CONICET-CIC) (Argentina); Chain, Cecilia Y.; Pasquevich, Alberto F. [Universidad Nacional de La Plata, Departamento de Fisica, IFLP, Facultad de Ciencias Exactas (Argentina); Rivas, Patricia C. [CONICET (Argentina); Martinez, Jorge A., E-mail: toto@fisica.unlp.edu.ar; Caracoche, Maria C. [Universidad Nacional de La Plata, Departamento de Fisica, IFLP, Facultad de Ciencias Exactas (Argentina)

2010-06-15

The short range technique of the Perturbed Angular Correlation (PAC) and x-ray diffraction (Rietveld) methods have been employed to determine the phase content in commercial mullite-zirconia and zircon raw materials that are ordinarily used to produce ceramic materials. The PAC technique, which probes zirconium-containing compounds at nanoscopic level, showed that zircon contains crystalline ZrSiO{sub 4} and an important amount of a structurally distorted zircon, which is also observed accompanying monoclinic zirconia in mullite-zirconia. This particular zircon phase was not detected by the long range x-ray diffraction-Rietveld technique. After an annealing treatment, important changes in crystalline contents of the powders allow confirming, by the x-ray diffraction-Rietveld method, the preexistence of this particular zircon phase. This fact must be taken into account when preparing multicomposites based on the present raw materials.

The International Lunar Decade Declaration

Science.gov (United States)

Beldavs, V.; Foing, B.; Bland, D.; Crisafulli, J.

2015-10-01

The International Lunar Decade Declaration was discussed at the conference held November 9-13, 2014 in Hawaii "The Next Giant Leap: Leveraging Lunar Assets for Sustainable Pathways to Space" - http://2014giantleap.aerospacehawaii.info/ and accepted by a core group that forms the International Lunar Decade Working Group (ILDWG) that is seeking to make the proposed global event and decade long process a reality. The Declaration will be updated from time to time by members of the ILDWreflecting new knowledge and fresh perspectives that bear on building a global consortium with a mission to progress from lunar exploration to the transformation of the Moon into a wealth gene rating platform for the expansion of humankind into the solar system. When key organizations have endorsed the idea and joined the effort the text of the Declaration will be considered final. An earlier International Lunar Decade proposal was issued at the 8th ICEUM Conference in 2006 in Beijing together with 13 specific initiatives for lunar exploration[1,2,3]. These initiatives have been largely implemented with coordination among the different space agencies involved provided by the International Lunar Exploration Working Group[2,3]. The Second International Lunar Decade from 2015 reflects current trends towards increasing involvement of commercial firms in space, particularly seeking opportunities beyond low Earth orbit. The central vision of the International Lunar Decade is to build the foundations for a sustainable space economy through international collaboration concurrently addressing Lunar exploration and building a shared knowledge base;Policy development that enables collabo rative research and development leading to lunar mining and industrial and commercial development;Infrastructure on the Moon and in cislunar space (communications, transport, energy systems, way-stations, other) that reduces costs, lowers risks and speeds up the time to profitable operations;Enabling technologies

Space Solar Power Technology Demonstration for Lunar Polar Applications: Laser-Photovoltaic Wireless Power Transmission

Science.gov (United States)

Henley, M. W.; Fikes, J. C.; Howell, J.; Mankins, J. C.; Howell, Joe T. (Technical Monitor)

2002-01-01

Space Solar Power technology offers unique benefits for near-term NASA space science missions, which can mature this technology for other future applications. "Laser-Photo-Voltaic Wireless Power Transmission" (Laser-PV WPT) is a technology that uses a laser to beam power to a photovoltaic receiver, which converts the laser's light into electricity. Future Laser-PV WPT systems may beam power from Earth to satellites or large Space Solar Power satellites may beam power to Earth, perhaps supplementing terrestrial solar photo-voltaic receivers. In a near-term scientific mission to the moon, Laser-PV WPT can enable robotic operations in permanently shadowed lunar polar craters, which may contain ice. Ground-based technology demonstrations are proceeding, to mature the technology for this initial application, in the moon's polar regions.

Energy for lunar resource exploitation

Science.gov (United States)

Glaser, Peter E.

1992-02-01

Humanity stands at the threshold of exploiting the known lunar resources that have opened up with the access to space. America's role in the future exploitation of space, and specifically of lunar resources, may well determine the level of achievement in technology development and global economic competition. Space activities during the coming decades will significantly influence the events on Earth. The 'shifting of history's tectonic plates' is a process that will be hastened by the increasingly insistent demands for higher living standards of the exponentially growing global population. Key to the achievement of a peaceful world in the 21st century, will be the development of a mix of energy resources at a societally acceptable and affordable cost within a realistic planning horizon. This must be the theme for the globally applicable energy sources that are compatible with the Earth's ecology. It is in this context that lunar resources development should be a primary goal for science missions to the Moon, and for establishing an expanding human presence. The economic viability and commercial business potential of mining, extracting, manufacturing, and transporting lunar resource based materials to Earth, Earth orbits, and to undertake macroengineering projects on the Moon remains to be demonstrated. These extensive activities will be supportive of the realization of the potential of space energy sources for use on Earth. These may include generating electricity for use on Earth based on beaming power from Earth orbits and from the Moon to the Earth, and for the production of helium 3 as a fuel for advanced fusion reactors.

KOREAN LUNAR LANDER – CONCEPT STUDY FOR LANDING-SITE SELECTION FOR LUNAR RESOURCE EXPLORATION

Directory of Open Access Journals (Sweden)

K. J. Kim

2016-06-01

Full Text Available As part of the national space promotion plan and presidential national agendas South Korea’s institutes and agencies under the auspices of the Ministry of Science, Information and Communication Technology and Future Planning (MSIP are currently developing a lunar mission package expected to reach Moon in 2020. While the officially approved Korean Pathfinder Lunar Orbiter (KPLO is aimed at demonstrating technologies and monitoring the lunar environment from orbit, a lander – currently in pre-phase A – is being designed to explore the local geology with a particular focus on the detection and characterization of mineral resources. In addition to scientific and potential resource potentials, the selection of the landing-site will be partly constrained by engineering constraints imposed by payload and spacecraft layout. Given today’s accumulated volume and quality of available data returned from the Moon’s surface and from orbital observations, an identification of landing sites of potential interest and assessment of potential hazards can be more readily accomplished by generating synoptic snapshots through data integration. In order to achieve such a view on potential landing sites, higher level processing and derivation of data are required, which integrates their spatial context, with detailed topographic and geologic characterizations. We are currently assessing the possibility of using fuzzy c-means clustering algorithms as a way to perform (semi- automated terrain characterizations of interest. This paper provides information and background on the national lunar lander program, reviews existing approaches – including methods and tools – for landing site analysis and hazard assessment, and discusses concepts to detect and investigate elemental abundances from orbit and the surface. This is achieved by making use of manual, semi-automated as well as fully-automated remote-sensing methods to demonstrate the applicability of

Glass and Glass-Ceramic Materials from Simulated Composition of Lunar and Martian Soils: Selected Properties and Potential Applications

Science.gov (United States)

Ray, C. S.; Sen, S.; Reis, S. T.; Kim, C. W.

2005-01-01

In-situ resource processing and utilization on planetary bodies is an important and integral part of NASA's space exploration program. Within this scope and context, our general effort is primarily aimed at developing glass and glass-ceramic type materials using lunar and martian soils, and exploring various applications of these materials for planetary surface operations. Our preliminary work to date have demonstrated that glasses can be successfully prepared from melts of the simulated composition of both lunar and martian soils, and the melts have a viscosity-temperature window appropriate for drawing continuous glass fibers. The glasses are shown to have the potential for immobilizing certain types of nuclear wastes without deteriorating their chemical durability and thermal stability. This has a direct impact on successfully and economically disposing nuclear waste generated from a nuclear power plant on a planetary surface. In addition, these materials display characteristics that can be manipulated using appropriate processing protocols to develop glassy or glass-ceramic magnets. Also discussed in this presentation are other potential applications along with a few selected thermal, chemical, and structural properties as evaluated up to this time for these materials.

Optimized Radiator Geometries for Hot Lunar Thermal Environments

Science.gov (United States)

Ochoa, Dustin

2013-01-01

The optimum radiator configuration in hot lunar thermal environments is one in which the radiator is parallel to the ground and has no view to the hot lunar surface. However, typical spacecraft configurations have limited real estate available for top-mounted radiators, resulting in a desire to use the spacecraft's vertically oriented sides. Vertically oriented, flat panel radiators will have a large view factor to the lunar surface, and thus will be subjected to significant incident lunar infrared heat. Consequently, radiator fluid temperatures will need to exceed approximately 325 K (assuming standard spacecraft radiator optical properties) in order to provide positive heat rejection at lunar noon. Such temperatures are too high for crewed spacecraft applications in which a heat pump is to be avoided. A recent study of vertically oriented radiator configurations subjected to lunar noon thermal environments led to the discovery of a novel radiator concept that yielded positive heat rejection at lower fluid temperatures. This radiator configuration, called the Intense Thermal Infrared Reflector (ITIR), has exhibited superior performance to all previously analyzed concepts in terms of heat rejection in the lunar noon thermal environment. A key benefit of ITIR is the absence of louvers or other moving parts and its simple geometry (no parabolic shapes). ITIR consists of a specularly reflective shielding surface and a diffuse radiating surface joined to form a horizontally oriented V-shape (shielding surface on top). The point of intersection of these surfaces is defined by two angles, those which define the tilt of each surface with respect to the local horizontal. The optimum set of these angles is determined on a case-by-case basis. The idea assumes minimal conductive heat transfer between shielding and radiating surfaces, and a practical design would likely stack sets of these surfaces on top of one another to reduce radiator thickness.

Ion Irradiation Damage in Zirconate and Titanate Ceramics for Pu Disposition

International Nuclear Information System (INIS)

Stewart, Martin W.; Begg, Bruce D.; Finnie, K.; Colella, Michael; Li, H.; McLeod, Terry; Smith, Katherine L.; Zhang, Zhaoming; Weber, William J.; Thevuthasan, Suntharampillai

2004-01-01

In this paper, we discuss the effect of ion irradiation on pyrochlore-rich titanate and defect-fluorite zirconate ceramics designed for plutonium immobilization. Samples, with Ce as an analogue for Pu, were made via oxide routes and consolidated by cold-pressing and sintering. Ion irradiation damage was carried out with 2 MeV Au2+ ions to a fluence of 5 ions nm-2 in the accelerator facilities within the Environmental Molecular Sciences Laboratory at Pacific Northwest National Laboratory. Irradiated and non-irradiated samples were examined by x-ray diffraction, scanning and transmission electron microscopy, x-ray photoelectron and infrared spectroscopy, and spectroscopic ellipsometry. Samples underwent accelerated leach testing at pH 1.75 (nitric acid) at 90 C for 28 days. The zirconate samples were more ion-irradiation damage resistant than the titanate samples, showing little change after ion-irradiation whereas the titanate samples formed an amorphous surface layer ∼ 500 nm thick. While all samples had high aqueous durability, the titanate leach rate was ∼ 5 times that of the zirconate. The ion-irradiation increased the leach rate of the titanate without impurities by ∼ 5 times. The difference in the leach rates between irradiated and unirradiated zirconate samples is small. However, the zirconates were less able to incorporate impurities than the titanate ceramics and required higher sintering temperatures, ∼ 1500 C compared to 1350 C for the titanates.

Theoretical modeling of zircon's crystal morphology according to data of atomistic calculations

Science.gov (United States)

Gromalova, Natalia; Nikishaeva, Nadezhda; Eremin, Nikolay

2017-04-01

Zircon is an essential mineral that is used in the U-Pb dating. Moreover, zircon is highly resistant to radioactive exposure. It is of great interest in solving both fundamental and applied problems associated with the isolation of high-level radioactive waste. There is significant progress in forecasting of the most energetically favorable crystal structures at the present time. Unfortunately, the theoretical forecast of crystal morphology at high technological level is under-explored nowadays, though the estimation of crystal equilibrium habit is extremely important in studying the physical and chemical properties of new materials. For the first time, the thesis about relation of the equilibrium shape of a crystal with its crystal structure was put forward in the works by O.Brave. According to it, the idealized habit is determined in the simplest case by a correspondence with the reticular densities Rhkl of individual faces. This approach, along with all subsequent corrections, does not take into account the nature of atoms and the specific features of the chemical bond in crystals. The atomistic calculations of crystal surfaces are commonly performed using the energetic characteristics of faces, namely, the surface energy (Esurf), which is a measure of the thermodynamic stability of the crystal face. The stable crystal faces are characterized by small positive values of Esurf. As we know from our previous research (Gromalova et al.,2015) one of the constitutive factors affecting the value of the surface energy in calculations is a choice of potentials model. In this regard, we studied several sets of parameters of atomistic interatomic potentials optimized previously. As the first test model («Zircon 1») were used sets of interatomic potentials of interaction Zr-O, Si-O and O-O in the form of Buckingham potentials. To improve playback properties of zircon additionally used Morse potential for a couple of Zr-Si, as well as the three-particle angular harmonic

Lunar Metal Oxide Electrolysis with Oxygen and Photovoltaic Array Production Applications

Science.gov (United States)

Curreri, P. A.; Ethridge, E.; Hudson, S.; Sen, S.

2006-01-01

This paper presents the results of a Marshall Space Flight Center funded effort to conduct an experimental demonstration of the processing of simulated lunar resources by the molten oxide electrolysis (MOE) process to produce oxygen and metal from lunar resources to support human exploration of space. Oxygen extracted from lunar materials can be used for life support and propellant, and silicon and metallic elements produced can be used for in situ fabrication of thin-film solar cells for power production. The Moon is rich in mineral resources, but it is almost devoid of chemical reducing agents, therefore, molten oxide electrolysis, MOE, is chosen for extraction, since the electron is the most practical reducing agent. MOE was also chosen for following reasons. First, electrolytic processing offers uncommon versatility in its insensitivity to feedstock composition. Secondly, oxide melts boast the twin key attributes of highest solubilizing capacity for regolith and lowest volatility of any candidate electrolytes. The former is critical in ensuring high productivity since cell current is limited by reactant solubility, while the latter simplifies cell design by obviating the need for a gas-tight reactor to contain evaporation losses as would be the case with a gas or liquid phase fluoride reagent operating at such high temperatures. In the experiments reported here, melts containing iron oxide were electrolyzed in a low temperature supporting oxide electrolyte (developed by D. Sadoway, MIT). The production of oxygen and reduced iron were observed. Electrolysis was also performed on the supporting electrolyte with JSC-1 Lunar Simulant. The cell current for the supporting electrolyte alone is negligible while the current for the electrolyte with JSC-1 shows significant current and a peak at about -0.6 V indicating reductive reaction in the simulant.

Bringing You the Moon: Lunar Education Efforts of the Center for Lunar Science and Education

Science.gov (United States)

Shaner, A. J.; Shupla, C.; Shipp, S.; Allen, J.; Kring, D. A.; Halligan, E.; LaConte, K.

2012-01-01

The Center for Lunar Science and Exploration (CLSE), a collaboration between the Lunar and Planetary Institute and NASA's Johnson Space Center, is one of seven member teams of the NASA Lunar Science Institute. In addition to research and exploration activities, the CLSE team is deeply invested in education and public outreach. Overarching goals of CLSE education are to strengthen the future science workforce, attract and retain students in STEM disciplines, and develop advocates for lunar exploration. The team's efforts have resulted in a variety of programs and products, including the creation of a variety of Lunar Traveling Exhibits and the High School Lunar Research Project, featured at http://www.lpi.usra.edu/nlsi/education/.

Lunar Prospector Orbit Determination Uncertainties Using the High Resolution Lunar Gravity Models

Science.gov (United States)

Carranza, Eric; Konopliv, Alex; Ryne, Mark

1999-01-01

The Lunar Prospector (LP) mission began on January 6, 1998, when the LP spacecraft was launched from Cape Canaveral, Florida. The objectives of the mission were to determine whether water ice exists at the lunar poles, generate a global compositional map of the lunar surface, detect lunar outgassing, and improve knowledge of the lunar magnetic and gravity fields. Orbit determination of LP performed at the Jet Propulsion Laboratory (JPL) is conducted as part of the principal science investigation of the lunar gravity field. This paper will describe the JPL effort in support of the LP Gravity Investigation. This support includes high precision orbit determination, gravity model validation, and data editing. A description of the mission and its trajectory will be provided first, followed by a discussion of the orbit determination estimation procedure and models. Accuracies will be examined in terms of orbit-to-orbit solution differences, as a function of oblateness model truncation, and inclination in the plane-of-sky. Long term predictions for several gravity fields will be compared to the reconstructed orbits to demonstrate the accuracy of the orbit determination and oblateness fields developed by the Principal Gravity Investigator.

Extrusion and properties of lead zirconate titanate piezoelectric ceramics

DEFF Research Database (Denmark)

Cai, S.; Millar, C.E.; Pedersen, L.

1997-01-01

The purpose of this work was to develop a procedure for fabricating electroceramic actuators with good piezoelectric properties. The preparation of lead zirconate titanate (PZT) piezoelectric ceramic rods and tubes by extrusion processing is described. The microstructure of extrudates was investi......The purpose of this work was to develop a procedure for fabricating electroceramic actuators with good piezoelectric properties. The preparation of lead zirconate titanate (PZT) piezoelectric ceramic rods and tubes by extrusion processing is described. The microstructure of extrudates...

Emerging technologies for processing and utilization of zircon

International Nuclear Information System (INIS)

Rao, S.M.; Balkishan, B.

2013-01-01

Zirconium occupies a prominent place in today's industry due to diverse applications of its chemical compounds. About 95% of zirconium is consumed in the form of zircon, zirconia and zirconium chemicals. The balance 5% of zirconium is consumed as the metal and its alloys. Because of its attractive nuclear properties zirconium alloys with very low hafnium content are used in the nuclear industry. Bio-compatibility, corrosion resistance and mechanical strength of zirconium alloys make them suitable for the manufacture of human organs and medicinal and pharmaceutical equipment. Other commercial areas of application of zirconium compounds include foundry, refractory, abrasives, opacifiers, oxygen sensors, catalysis, advanced ceramics, gems, paint dryers, pigments etc. The talk outlines the technologies involved in the production of nuclear grade zirconium alloys, manufacture of zirconium metal powder, gem grade zirconia and zirconium compounds like oxy-chloride, basic sulphate and basic carbonate etc. (author)

MOONLIGHT: A NEW LUNAR LASER RANGING RETROREFLECTOR AND THE LUNAR GEODETIC PRECESSION

Directory of Open Access Journals (Sweden)

M. Martini

2013-12-01

Full Text Available Since the 1970s Lunar Laser Ranging (LLR to the Apollo Cube Corner Retroreflector (CCR arrays (developed by the University of Maryland, UMD supplied almost all significant tests of General Relativity (Alley et al., 1970; Chang et al., 1971; Bender et al.,1973: possible changes in the gravitational constant, gravitational self-energy, weak equivalence principle, geodetic precession, inverse-square force-law. The LNF group, in fact, has just completed a new measurement of the lunar geodetic precession with Apollo array, with accuracy of 9 × 10−3, comparable to the best measurement to date. LLR has also provided significant information on the composition and origin of the moon. This is the only Apollo experiment still in operation. In the 1970s Apollo LLR arrays contributed a negligible fraction of the ranging error budget. Since the ranging capabilities of ground stations improved by more than two orders of magnitude, now, because of the lunar librations, Apollo CCR arrays dominate the error budget. With the project MoonLIGHT (Moon Laser Instrumentation for General relativity High-accuracy Tests, in 2006 INFN-LNF joined UMD in the development and test of a new-generation LLR payload made by a single, large CCR (100mm diameter unaffected by the effect of librations. With MoonLIGHT CCRs the accuracy of the measurement of the lunar geodetic precession can be improved up to a factor 100 compared to Apollo arrays. From a technological point of view, INFN-LNF built and is operating a new experimental apparatus (Satellite/lunar laser ranging Characterization Facility, SCF and created a new industry-standard test procedure (SCF-Test to characterize and model the detailed thermal behavior and the optical performance of CCRs in accurately laboratory-simulated space conditions, for industrial and scientific applications. Our key experimental innovation is the concurrent measurement and modeling of the optical Far Field Diffraction Pattern (FFDP and the

Effect of pressure on Zircon's (ZrSiO4) Raman active modes: a first-principles study

Science.gov (United States)

Sheremetyeva, Natalya; Cherniak, Daniele; Watson, Bruce; Meunier, Vincent

Zircon is a mineral commonly found in the Earth crust. Its remarkable properties have given rise to considerable attention. This includes possible inclusion of radioactive elements in natural samples, which allows for geochronological investigations. Subsequently, Zircon was proposed as possible host material for radioactive waste management. Internal radiation damage in zircon leads to the destruction of its crystal structure (an effect known as metamictization) which is subject to ongoing research. Recently, the effect of pressure and temperature on synthetic zircon has been analyzed experimentally using Raman spectroscopy which led to the calibration of zircon as a pressure sensor in diamond-anvil cell experiments. While there have been a number of theoretical studies, the effect of pressure on the Raman active modes of zircon has not been investigated theoretically. Here we present a first-principles pressure calibration of the Raman active modes in Zircon employing density-functional theory (DFT). We find excellent quantitative agreement of the slopes ∂ω / ∂P with the experimental ones and are able to rationalize the ω vs. P behavior based on the details of the vibrational modes.

High-temperature mechanical properties of a uniaxially reinforced zircon-silicon carbide composite

International Nuclear Information System (INIS)

Singh, R.N.

1990-01-01

This paper reports that mechanical properties of a monolithic zircon ceramic and zircon-matrix composites uniaxially reinforced with either uncoated or BN-coated silicon carbide monofilaments were measured in flexure between 25 degrees and 1477 degrees C. Monolithic zircon ceramics were weak and exhibited a brittle failure up to abut 1300 degrees C. An increasing amount of the plastic deformation was observed before failure above about 1300 degrees C. In contrast, composites reinforced with either uncoated or BN-coated Sic filaments were stronger and tougher than the monolithic zircon at all test temperatures between 25 degrees and 1477 degrees. The ultimate strength and work-of-fracture of composite samples decreased with increasing temperature. A transgranular matrix fracture was shown by the monolithic and composite samples tested up to about 1200 degrees C, whereas an increasing amount of the intergranular matrix fracture was displayed above 1200 degrees C

Endogenous Lunar Volatiles

Science.gov (United States)

McCubbin, F. M.; Liu, Y.; Barnes, J. J.; Anand, M.; Boyce, J. W.; Burney, D.; Day, J. M. D.; Elardo, S. M.; Hui, H.; Klima, R. L.; Magna, T.; Ni, P.; Steenstra, E.; Tartèse, R.; Vander Kaaden, K. E.

2018-04-01

This abstract discusses numerous outstanding questions on the topic of endogenous lunar volatiles that will need to be addressed in the coming years. Although substantial insights into endogenous lunar volatiles have been gained, more work remains.

Lunar imaging and ionospheric calibration for the Lunar Cherenkov technique

NARCIS (Netherlands)

McFadden, R.; Scholten, O.; Mevius, M.

2013-01-01

The Lunar Cherenkov technique is a promising method for UHE neutrino and cosmic ray detection which aims to detect nanosecond radio pulses produced during particle interactions in the Lunar regolith. For low frequency experiments, such as NuMoon, the frequency dependent dispersive effect of the

Kickstarting a New Era of Lunar Industrialization via Campaign of Lunar COTS Missions

Science.gov (United States)

Zuniga, Allison F.; Turner, Mark; Rasky, Daniel; Pittman, Robert B.; Zapata, Edgar

2016-01-01

To support the goals of expanding our human presence and current economic sphere beyond LEO, a new plan was constructed for NASA to enter into partnerships with industry to foster and incentivize a new era of lunar industrialization. For NASA to finally be successful in achieving sustainable human exploration missions beyond LEO, lessons learned from our space history have shown that it is essential for current program planning to include affordable and economic development goals as well as address top national priorities to obtain much needed public support. In the last 58 years of NASA's existence, only Apollo's human exploration missions beyond LEO were successful since it was proclaimed to be a top national priority during the 1960's. However, the missions were not sustainable and ended abruptly in 1972 due to lack of funding and insufficient economic gain. Ever since Apollo, there have not been any human missions beyond LEO because none of the proposed program plans were economical or proclaimed a top national priority. The proposed plan outlines a new campaign of low-cost, commercial-enabled lunar COTS (Commercial Orbital Transfer Services) missions which is an update to the Lunar COTS plan previously described. The objectives of this new campaign of missions are to prospect for resources, determine the economic viability of extracting those resources and assess the value proposition of using these resources in future exploration architectures such as Mars. These missions would be accomplished in partnership with commercial industry using the wellproven COTS Program acquisition model. This model proved to be very beneficial to both NASA and its industry partners as NASA saved significantly in development and operational costs, as much as tenfold, while industry partners successfully expanded their market share and demonstrated substantial economic gain. Similar to COTS, the goals for this new initiative are 1) to develop and demonstrate cost-effective, cis-lunar

A neutron and synchrotron investigation of the electronic structure of lanthanide zirconates

International Nuclear Information System (INIS)

Clements, Richard; Kennedy, Brendan; Ling, Chris; Stampfl, Anton P.J.

2009-01-01

Full text: The lanthanide zirconates are of interest for use in inert matrix fuels and nuclear wasteforms. A variety of studies have been performed to determine the suitability of a material as an inert matrix or wasteform. For use in these applications, the material's structure must be resistant to radiation damage and its thermal, thermodynamic and mechanical properties must be known. The structure's ability to incorporate an actinide host into the lattice vacancy must also be known. These properties may be better understood by investigating the f-electronic structure, which has historically proved difficult to model. We have undertaken a synthesis of the full range of lanthanide zirconate series using solid state techniques. We have performed neutron powder diffraction on a selection of the series in conjunction with the following measurements using synchrotron radiation: powder x-ray diffraction, VUV photoluminescence spectra, x-ray photoemission spectroscopy (XPS) and x-ray absorption near edge spectroscopy (XANES) The results are to be analysed using OFT modeling techniques. These results will be presented, along with details of the analysis and synthetic techniques used.

Technicians work with Apollo 14 lunar sample material in Lunar Receiving Lab.

Science.gov (United States)

1971-01-01

Glove handlers work with freshly opened Apollo 14 lunar sample material in modularized cabinets in the Lunar Receiving Laboratory at the Manned Spacecraft Center. The glove operator on the right starts to pour fine lunar material which he has just taken from a tote bag. This powdery sample was among the last to be revealed of the 90-odd pounds of material brought back to Earth by the Apollo 14 crewmen.

Orbital studies of lunar magnetism

Science.gov (United States)

Mcleod, M. G.; Coleman, P. J., Jr.

1982-01-01

Limitations of present lunar magnetic maps are considered. Optimal processing of satellite derived magnetic anomaly data is also considered. Studies of coastal and core geomagnetism are discussed. Lunar remanent and induced lunar magnetization are included.

Enthalpy of formation of zircon

International Nuclear Information System (INIS)

Ellison, A.J.G.; Navrotsky, A.

1992-01-01

Using high-temperature solution calorimetry in molt 2PbO · B 2 O 3 , the enthalpy of reaction of the formation of zircon, ZrSiO 4 , from its constituent oxides has been determined: Δ 4 H 977 (ZrSiO 4 ) = -27.9 (±1.9) kJ/mol. With previously reported data for the heat contents of ZrO 2 SiO 2 and ZrSiO 4 and standard-state enthalpies of formation of ZrO 2 and SiO 2 , we obtain Δ f H 298 degrees. (ZrSiO 4 ) = -2034.2 (±3.1) kJ/mol and Δ t G 298 degrees (ZrSiO 4 ) = -1919.8 kJ/mol. The free energy value is in excellent agreement with a range previously estimated from solid-state reaction equilibria. At higher temperature also the data are in close agreement with existing data, though the data sets diverge somewhat with increasing T. In this paper the limitations of the data for predicting the breakdown temperature of zircon into its constituent oxides are discussed

Microwave-assisted hydrothermal synthesis of lead zirconate fine powders

Directory of Open Access Journals (Sweden)

Apinpus Rujiwatra

2011-01-01

Full Text Available A rapid synthesis of lead zirconate fine powders by microwave-assisted hydrothermal technique is reported. The influences of type of lead precursor, concentration of potassium hydroxide mineraliser, applied microwave power and irradiation time are described. The synthesised powders were characterised by powder X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopic microanalysis and light scattering technique. The merits of the microwave application in reducing reaction time and improving particle mono-dispersion and size uniformity as well as the drawbacks, viz. low purity of the desired phase and increasing demand of mineraliser, are discussed in relation to conventional heating method.

Current—voltage characteristics of lead zirconate titanate/nickel bilayered hollow cylindrical magnetoelectric composites

International Nuclear Information System (INIS)

De-An, Pan; Shen-Gen, Zhang; Jian-Jun, Tian; Li-Jie, Qiao; Jun-Sai, Sun; Volinsky, Alex A.

2010-01-01

Current–voltage measurements obtained from lead zirconate titanate/nickel bilayered hollow cylindrical magnetoelectric composite showed that a sinusoidal current applied to the copper coil wrapped around the hollow cylinder circumference induces voltage across the lead zirconate titanate layer thickness. The current–voltage coefficient and the maximum induced voltage in lead zirconate titanate at 1 kHz and resonance (60.1 kHz) frequencies increased linearly with the number of the coil turns and the applied current. The resonance frequency corresponds to the electromechanical resonance frequency. The current–voltage coefficient can be significantly improved by optimizing the magnetoelectric structure geometry and/or increasing the number of coil turns. Hollow cylindrical lead zirconate titanate/nickel structures can be potentially used as current sensors. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Detrital zircon ages in Buller and Takaka terranes, New Zealand : constraints on early Zealandia history

International Nuclear Information System (INIS)

Adams, C.J.; Mortimer, N.; Campbell, H.J.; Griffin, W.L.

2015-01-01

Detrital zircon ages are presented for 34 early Palaeozoic sandstones from Buller and Takaka terranes, New Zealand, and formerly adjacent parts of Australia-Antarctica. The Buller-Takaka datasets always have two major groups: Ordovician-late Neoproterozoic, 444-700 Ma (but mainly 540-700 Ma), termed 'Gondwana Assembly' (GA), and early Neoproterozoic-Mesoproterozoic, 700-1600 Ma (but mainly 900-1200 Ma), termed 'Rodinia Assembly' (RA). In both terranes, significant age components within these groups are strikingly similar and also have RA/GA ratios, 0.6-1.8. The Cambrian volcanic arc of the Takaka Terrane has contributed little to the zircon patterns. Proportions of Late Cambrian-Early Ordovician zircons, characteristic of granitoid sources in the Ross-Delamerian Orogen are low. The zircons are predominantly reworked with contemporary zircons only evident in a few Buller datasets. The zircon patterns suggest that two major sources (late Mesoproterozoic and late Neoproterozoic), enduring over 120 Ma, were widely distributed and it is postulated they form Precambrian basement beneath southern Zealandia. (author).

Can Fractional Crystallization of a Lunar Magma Ocean Produce the Lunar Crust?

Science.gov (United States)

Rapp, Jennifer F.; Draper, David S.

2013-01-01

New techniques enable the study of Apollo samples and lunar meteorites in unprecedented detail, and recent orbital spectral data reveal more about the lunar farside than ever before, raising new questions about the supposed simplicity of lunar geology. Nevertheless, crystallization of a global-scale magma ocean remains the best model to account for known lunar lithologies. Crystallization of a lunar magma ocean (LMO) is modeled to proceed by two end-member processes - fractional crystallization from (mostly) the bottom up, or initial equilibrium crystallization as the magma is vigorously convecting and crystals remain entrained, followed by crystal settling and a final period of fractional crystallization [1]. Physical models of magma viscosity and convection at this scale suggest that both processes are possible. We have been carrying out high-fidelity experimental simulations of LMO crystallization using two bulk compositions that can be regarded as end-members in the likely relevant range: Taylor Whole Moon (TWM) [2] and Lunar Primitive Upper Mantle (LPUM) [3]. TWM is enriched in refractory elements by 1.5 times relative to Earth, whereas LPUM is similar to the terrestrial primitive upper mantle, with adjustments made for the depletion of volatile alkalis observed on the Moon. Here we extend our earlier equilibrium-crystallization experiments [4] with runs simulating full fractional crystallization

Ancient xenocrystic zircon in young volcanic rocks of the southern Lesser Antilles island arc

Science.gov (United States)

Rojas-Agramonte, Yamirka; Williams, Ian S.; Arculus, Richard; Kröner, Alfred; García-Casco, Antonio; Lázaro, Concepción; Buhre, Stephan; Wong, Jean; Geng, Helen; Echeverría, Carlos Morales; Jeffries, Teresa; Xie, Hangqian; Mertz-Kraus, Regina

2017-10-01

The Lesser Antilles arc is one of the best global examples in which to examine the effects of the involvement of subducted sediment and crustal assimilation in the generation of arc crust. Most of the zircon recovered in our study of igneous and volcaniclastic rocks from Grenada and Carriacou (part of the Grenadines chain) is younger than 2 Ma. Within some late Paleogene to Neogene ( 34-0.2 Ma) lavas and volcaniclastic sediments however, there are Paleozoic to Paleoarchean ( 250-3469 Ma) xenocrysts, and Late Jurassic to Precambrian zircon ( 158-2667 Ma) are found in beach and river sands. The trace element characteristics of zircon clearly differentiate between different types of magmas generated in the southern Lesser Antilles through time. The zircon population from the younger arc (Miocene, 22-19 Ma, to Present) has minor negative Eu anomalies, well-defined positive Ce anomalies, and a marked enrichment in heavy rare earth elements (HREE), consistent with crystallization from very oxidized magmas in which Eu2 + was in low abundance. In contrast, zircon from the older arc (Eocene to mid-Oligocene, 30-28 Ma) has two different REE patterns: 1) slight enrichment in the light (L)REE, small to absent Ce anomalies, and negative Eu anomalies and 2) enriched High (H)REE, positive Ce anomalies and negative Eu anomalies (a similar pattern is observed in the xenocrystic zircon population). The combination of positive Ce and negative Eu anomalies in the zircon population of the older arc indicates crystallization from magmas that were variably, but considerably less oxidized than those of the younger arc. All the igneous zircon has positive εHf(t), reflecting derivation from a predominantly juvenile mantle source. However, the εHf(t) values vary significantly within samples, reflecting considerable Hf isotopic heterogeneity in the source. The presence of xenocrystic zircon in the southern Lesser Antilles is evidence for the assimilation of intra-arc crustal sediments and

Perfect zircon for rock dating no fairy tale

International Nuclear Information System (INIS)

Anon

2000-01-01

The scheme used to date rocks is based on the radioactive decay of uranium. Minute traces of uranium locked inside the zircon crystals have been decaying over aeons, producing lead. Scientists know that the decay occurs at a fixed rate and how quickly it happens. By measuring the relative amounts of uranium and lead encased in the crystals, scientists can determine how old the rock is. But sometimes lead is lost from zircon crystals via processes such as weathering (if the rocks were exposed on the surface) or deformation and metamorphism (if the rocks had crystallised deep in the earth and been subjected to high temperatures and pressure). Hence the special nature of the Temora rocks- a 417 million years old zirconium-containing rock which have been partially exposed in recent times in a remote paddock in NSW, Australia. SHRIMP dating was used for initial tests on the Temora rocks. Then, in December last year, the sample was sent to the world-recognised authority, Canada's Royal Ontario Museum, for independent analysis and dating via chemical decomposition. The museum confirmed the near perfect quality of the zircon and its age

Late magmatic stage of the zoned Caleu pluton (Central Chile): insights from zircon crystallization conditions

Science.gov (United States)

Molina, P. G.; Parada, M.; Gutierrez, F. J.; Chang-Qiang, M.; Jianwei, L.; Yuanyuan, L.

2012-12-01

The Caleu pluton consists of three N-S elongated lithological zones: Gabbro-Diorite Zone (GDZ), Tonalite Zone (TZ) and Granodiorite Zone (GZ); western, middle and eastern portions of the pluton, respectively. The zones are thought to be previously differentiated in a common, isotopically depleted (Sr-Nd), subjacent magma reservoir at a 4 kbar equivalent depth. The emplacement should have occurred at the climax of the Cretaceous rifting. We present preliminary results of U238/Pb206 zircon geochronology; zircon saturation, Tsat(Zrn), and crystallization temperatures (Ti-in-Zrn); as well as relative oxidation states at time of crystallization, based on: (i) the sluggish REE and HFSE subsolidus diffusivities in zircon; (ii) the behavior of Ti4+↔Si4+ and Ce4+↔Zr4+ isovalent replacement, in addition to a constrained TiO2 activity in almost all typical crustal rocks; and (iii) relative oxidation states at time of crystallization, respectively. The latter are obtained by interpolation of the partition coefficients of trivalent (REE) and tetravalent (HFSE) curves in Onuma diagrams for each zircon, and then estimating relative Ce(IV)/Ce(III) ratios. Results obtained from 4 samples (a total of 77 zircon grains) collected from the three mentioned lithological zones indicate U/Pb ages of approximately 99.5 ±1.5 Ma, 96.8 ±0.6 Ma, and 94.4 +2.2 -0.8 Ma; and Ti-in Zrn ranges of ca. 720-870°C, ca. 680-820°C and ca. 750-840°C, for the GDZ, TZ and GZ samples, respectively. On the other hand Tsat(Zrn) of ca. 750-780°C in the TZ, and ca. 830-890°C in the GZ, were obtained. As expected saturation temperatures are similar or higher than Ti-in-Zrn obtained in zircon grains of TZ and GZ, respectively. Cathodoluminiscence images in zircon suggest a magmatic origin, due to absence of complex zoning patterns and fairly well conserved morphologies. Exceptionally the GDZ sample zircons show evidence of inheritance, indicating a xenocrystic and/or antecrystic origin. A relative Ce

A Dual Launch Robotic and Human Lunar Mission Architecture

Science.gov (United States)

Jones, David L.; Mulqueen, Jack; Percy, Tom; Griffin, Brand; Smitherman, David

2010-01-01

paper describes a complete transportation architecture including the analysis of transportation element options and sensitivities including: transportation element mass to surface landed mass; lander propellant options; and mission crew size. Based on this analysis, initial design concepts for the launch vehicle, crew module and lunar lander are presented. The paper also describes how the dual launch lunar mission architecture would fit into a more general overarching human space exploration philosophy that would allow expanded application of mission transportation elements for missions beyond the Earth-moon realm.

Lunar ash flows - Isothermal approximation.

Science.gov (United States)

Pai, S. I.; Hsieh, T.; O'Keefe, J. A.

1972-01-01

Suggestion of the ash flow mechanism as one of the major processes required to account for some features of lunar soil. First the observational background and the gardening hypothesis are reviewed, and the shortcomings of the gardening hypothesis are shown. Then a general description of the lunar ash flow is given, and a simple mathematical model of the isothermal lunar ash flow is worked out with numerical examples to show the differences between the lunar and the terrestrial ash flow. The important parameters of the ash flow process are isolated and analyzed. It appears that the lunar surface layer in the maria is not a residual mantle rock (regolith) but a series of ash flows due, at least in part, to great meteorite impacts. The possibility of a volcanic contribution is not excluded. Some further analytic research on lunar ash flows is recommended.

Zircon evidence for incorporation of terrigenous sediments into the magma source of continental basalts.

Science.gov (United States)

Xu, Zheng; Zheng, Yong-Fei; Zhao, Zi-Fu

2018-01-09

Crustal components may be incorporated into continental basalts by either shallow contamination or deep mixing. While the former proceeds at crustal depths with common preservation of refractory minerals, the latter occurs at mantle depths with rare survival of relict minerals. Discrimination between the two mechanisms has great bearing to subcontinental mantle geochemistry. Here we report the occurrence of relict zircons in Cenozoic continental basalts from eastern China. A combined study of zircon U-Pb ages and geochemistry indicates that detrital zircons were carried by terrigenous sediments into a subcontinental subduction zone, where the zircon were transferred by fluids into the magma sources of continental basalts. The basalts were sampled from three petrotectonic units with distinct differences in their magmatic and metamorphic ages, making the crustal contamination discernible. The terrigenous sediments were carried by the subducting oceanic crust into the asthenospheric mantle, producing both soluble and insoluble materials at the slab-mantle interface. These materials were served as metasomatic agents to react with the overlying mantle wedge peridotite, generating a kind of ultramafic metasomatites that contain the relict zircons. Therefore, the occurrence of relict zircons in continental basalts indicates that this refractory mineral can survive extreme temperature-pressure conditions in the asthenospheric mantle.

Conceptual design of a lunar oxygen pilot plant Lunar Base Systems Study (LBSS) task 4.2

Science.gov (United States)

1988-01-01

The primary objective was to develop conceptual designs of two pilot plants to produce oxygen from lunar materials. A lunar pilot plant will be used to generate engineering data necessary to support an optimum design of a larger scale production plant. Lunar oxygen would be of primary value as spacecraft propellant oxidizer. In addition, lunar oxygen would be useful for servicing nonregenerative fuel cell power systems, providing requirements for life support, and to make up oxygen losses from leakage and airlock cycling. Thirteen different lunar oxygen production methods are described. Hydrogen reduction of ilmenite and extraction of solar-wind hydrogen from bulk lunar soil were selected for conceptual design studies. Trades and sensitivity analyses were performed with these models.

Lunar and Vesta Web Portals

Science.gov (United States)

Law, E.; JPL Luna Mapping; Modeling Project Team

2015-06-01

The Lunar Mapping and Modeling Project offers Lunar Mapping and Modeling Portal (http://lmmp.nasa.gov) and Vesta Trek Portal (http://vestatrek.jpl.nasa.gov) providing interactive visualization and analysis tools to enable users to access mapped Lunar and Vesta data products.

Lunar Lava Tube Sensing

Science.gov (United States)

York, Cheryl Lynn; Walden, Bryce; Billings, Thomas L.; Reeder, P. Douglas

1992-01-01

Large (greater than 300 m diameter) lava tube caverns appear to exist on the Moon and could provide substantial safety and cost benefits for lunar bases. Over 40 m of basalt and regolith constitute the lava tube roof and would protect both construction and operations. Constant temperatures of -20 C reduce thermal stress on structures and machines. Base designs need not incorporate heavy shielding, so lightweight materials can be used and construction can be expedited. Identification and characterization of lava tube caverns can be incorporated into current precursor lunar mission plans. Some searches can even be done from Earth. Specific recommendations for lunar lava tube search and exploration are (1) an Earth-based radar interferometer, (2) an Earth-penetrating radar (EPR) orbiter, (3) kinetic penetrators for lunar lava tube confirmation, (4) a 'Moon Bat' hovering rocket vehicle, and (5) the use of other proposed landers and orbiters to help find lunar lava tubes.

The Lunar Magma Ocean (LMO) Paradigm Versus the Realities of Lunar Anorthosites

Science.gov (United States)

Treiman, A. H.; Gross, J.

2018-05-01

The paradigm of the Lunar Magma Ocean (LMO) is inconsistent with much chemical and compositional data on lunar anorthosites. The paradigm of serial anorthosite diapirism is more consistent, though not a panacea.

Chronology of early lunar crust

International Nuclear Information System (INIS)

Dasch, E.J.; Nyquist, L.E.; Ryder, G.

1988-01-01

The chronology of lunar rocks is summarized. The oldest pristine (i.e., lacking meteoritic contamination of admixed components) lunar rock, recently dated with Sm-Nd by Lugmair, is a ferroan anorthosite, with an age of 4.44 + 0.02 Ga. Ages of Mg-suite rocks (4.1 to 4.5 Ga) have large uncertainties, so that age differences between lunar plutonic rock suites cannot yet be resolved. Most mare basalts crystallized between 3.1 and 3.9 Ga. The vast bulk of the lunar crust, therefore, formed before the oldest preserved terrestrial rocks. If the Moon accreted at 4.56 Ga, then 120 Ma may have elapsed before lunar crust was formed

The Lunar Dust Environment

Science.gov (United States)

Szalay, Jamey Robert

Planetary bodies throughout the solar system are continually bombarded by dust particles, largely originating from cometary activities and asteroidal collisions. Surfaces of bodies with thick atmospheres, such as Venus, Earth, Mars and Titan are mostly protected from incoming dust impacts as these particles ablate in their atmospheres as 'shooting stars'. However, the majority of bodies in the solar system have no appreciable atmosphere and their surfaces are directly exposed to the flux of high speed dust grains. Impacts onto solid surfaces in space generate charged and neutral gas clouds, as well as solid secondary ejecta dust particles. Gravitationally bound ejecta clouds forming dust exospheres were recognized by in situ dust instruments around the icy moons of Jupiter and Saturn, and had not yet been observed near bodies with refractory regolith surfaces before NASA's Lunar Dust and Environment Explorer (LADEE) mission. In this thesis, we first present the measurements taken by the Lunar Dust Explorer (LDEX), aboard LADEE, which discovered a permanently present, asymmetric dust cloud surrounding the Moon. The global characteristics of the lunar dust cloud are discussed as a function of a variety of variables such as altitude, solar longitude, local time, and lunar phase. These results are compared with models for lunar dust cloud generation. Second, we present an analysis of the groupings of impacts measured by LDEX, which represent detections of dense ejecta plumes above the lunar surface. These measurements are put in the context of understanding the response of the lunar surface to meteoroid bombardment and how to use other airless bodies in the solar system as detectors for their local meteoroid environment. Third, we present the first in-situ dust measurements taken over the lunar sunrise terminator. Having found no excess of small grains in this region, we discuss its implications for the putative population of electrostatically lofted dust.

Geochemical fingerprints and pebbles zircon geochronology

Indian Academy of Sciences (India)

Home; Journals; Journal of Earth System Science; Volume 125; Issue 7. Geochemical fingerprints and pebbles zircon geochronology: Implications for the provenance and tectonic setting of Lower Cretaceous sediments in the Zhucheng Basin (Jiaodong peninsula, North China). Jin-Long Ni Jun-Lai Liu Xiao-Ling Tang ...

Uranium and Thorium in zircon sands processed in Northeastern Brazil

International Nuclear Information System (INIS)

Hazin, Clovis A.; Farias, Emerson E. G. de

2008-01-01

Zircon the main mineral of zirconium is a silicate mineral product (ZrSiO 4 ) obtained from beach sand deposits, along with other minerals such as kyanite, ilmenite, and rutile. All zircons contain some radioactive impurities due to the presence of uranium, thorium and their respective decay products in the crystalline structure of zircon, as well as potassium-40. Uranium and thorium substitute Zr 4+ in the mineral through an internal process called isomorphous replacement of zirconium. For this study, samples were collected both from a mineral sand processing plant located in the coastal region of Northeastern brazil and from the beach sands used in the process. The aim of this study was to assess the 238 U, 232 Th and 40 K contents in the beach sands and in the mineral products extracted from the sands in that facility, with special emphasis on zircon. Measurements were performed through gamma spectrometry, by using a high-purity germanium detector (HPGe) coupled to a multichannel analyzer. Activity concentration for 238 U and 232 Th in zircon sands ranged from 5462±143 to 19286±46 Bq kg -1 and from 1016±7 to 7162±38 Bq kg -1 , respectively. For 40 K, on the other hand, activity concentration values ranged from 81±14 to 681±26 Bq Kg -1 . The results of the measurements carried out for raw sand samples showed activity concentrations between 2.7±0.6 and 7.9±0.9 Bq kg -1 and 6.5±0.4 and 9.4±0.6 Bq kg -1 for 238 U and 23T h respectively, and from 48.8±3.1 to 76.1±2.4 Bq kg -1 for 40 K. Activity concentrations of 238 U and 232 Th in kyanite, ilmenite and rutile samples were also determined. (author)

Echo simulation of lunar penetrating radar: based on a model of inhomogeneous multilayer lunar regolith structure

Science.gov (United States)

Dai, Shun; Su, Yan; Xiao, Yuan; Feng, Jian-Qing; Xing, Shu-Guo; Ding, Chun-Yu

2014-12-01

Lunar Penetrating Radar (LPR) based on the time domain Ultra-Wideband (UWB) technique onboard China's Chang'e-3 (CE-3) rover, has the goal of investigating the lunar subsurface structure and detecting the depth of lunar regolith. An inhomogeneous multi-layer microwave transfer inverse-model is established. The dielectric constant of the lunar regolith, the velocity of propagation, the reflection, refraction and transmission at interfaces, and the resolution are discussed. The model is further used to numerically simulate and analyze temporal variations in the echo obtained from the LPR attached on CE-3's rover, to reveal the location and structure of lunar regolith. The thickness of the lunar regolith is calculated by a comparison between the simulated radar B-scan images based on the model and the detected result taken from the CE-3 lunar mission. The potential scientific return from LPR echoes taken from the landing region is also discussed.

Echo simulation of lunar penetrating radar: based on a model of inhomogeneous multilayer lunar regolith structure

International Nuclear Information System (INIS)

Dai Shun; Su Yan; Xiao Yuan; Feng Jian-Qing; Xing Shu-Guo; Ding Chun-Yu

2014-01-01

Lunar Penetrating Radar (LPR) based on the time domain Ultra-Wideband (UWB) technique onboard China's Chang'e-3 (CE-3) rover, has the goal of investigating the lunar subsurface structure and detecting the depth of lunar regolith. An inhomogeneous multi-layer microwave transfer inverse-model is established. The dielectric constant of the lunar regolith, the velocity of propagation, the reflection, refraction and transmission at interfaces, and the resolution are discussed. The model is further used to numerically simulate and analyze temporal variations in the echo obtained from the LPR attached on CE-3's rover, to reveal the location and structure of lunar regolith. The thickness of the lunar regolith is calculated by a comparison between the simulated radar B-scan images based on the model and the detected result taken from the CE-3 lunar mission. The potential scientific return from LPR echoes taken from the landing region is also discussed

Lunar Atmosphere Probe Station: A Proof-of-Concept Instrument Package for Monitoring the Lunar Atmosphere

Science.gov (United States)

Lazio, J.; Jones, D. L.; MacDowall, R. J.; Stewart, K. P.; Burns, J. O.; Farrell, W. M.; Giersch, L.; O'Dwyer, I. J.; Hicks, B. C.; Polisensky, E. J.; Hartman, J. M.; Nesnas, I.; Weiler, K.; Kasper, J. C.

2013-12-01

The lunar exosphere is the exemplar of a plasma near the surface of an airless body. Exposed to both the solar and interstellar radiation fields, the lunar exosphere is mostly ionized, and enduring questions regarding its properties include its density and vertical extent, the extent of contributions from volatile outgassing from the Moon, and its behavior over time, including response to the solar wind and modification by landers. Relative ionospheric measurements (riometry) are based on the simple physical principle that electromagnetic waves cannot propagate through a partially or fully ionized medium below the plasma frequency, and riometers have been deployed on the Earth in numerous remote and hostile environments. A multi-frequency riometer on the lunar surface would be able to monitor, *in situ*, the vertical extent of the lunar exosphere over time. We provide an update on a concept for a riometer implemented as a secondary science payload on future lunar landers, such as those recommended in the recent Planetary Sciences Decadal Survey report or commercial ventures. The instrument concept is simple, consisting of an antenna implemented as a metal deposited on polyimide film and receiver. We illustrate various deployment mechanisms and performance of a prototype in increasing lunar analog conditions. While the prime mission of such a riometer would be probing the lunar exosphere, our concept would also be capable to measuring the properties of dust impactors. The Lunar University Network for Astrophysical Research consortium is funded by the NASA Lunar Science Institute to investigate concepts for astrophysical observatories on the Moon. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. Artist's impression of the Lunar Atmosphere Probe Station.

Beneficiation of lunar ilmenite

Science.gov (United States)

Ruiz, Joaquin

1991-01-01

One of the most important commodities lacking in the moon is free oxygen which is required for life and used extensively for propellent. Free oxygen, however, can be obtained by liberating it from the oxides and silicates that form the lunar rocks and regolith. Ilmenite (FeTiO3) is considered one of the leading candidates for production of oxygen because it can be reduced with a reasonable amount of energy and it is an abundant mineral in the lunar regolith and many mare basalts. In order to obtain oxygen from ilmenite, a method must be developed to beneficiate ilmenite from lunar material. Two possible techniques are electrostatic or magnetic methods. Both methods have complications because lunar ilmenite completely lacks Fe(3+). Magnetic methods were tested on eucrite meteorites, which are a good chemical simulant for low Ti mare basalts. The ilmenite yields in the experiments were always very low and the eucrite had to be crushed to xxxx. These data suggest that magnetic separation of ilmenite from fine grain lunar basalts would not be cost effective. Presently, experiments are being performed with electrostatic separators, and lunar regolith is being waited for so that simulants do not have to be employed.

Use of Open Standards and Technologies at the Lunar Mapping and Modeling Project

Science.gov (United States)

Law, E.; Malhotra, S.; Bui, B.; Chang, G.; Goodale, C. E.; Ramirez, P.; Kim, R. M.; Sadaqathulla, S.; Rodriguez, L.

2011-12-01

The Lunar Mapping and Modeling Project (LMMP), led by the Marshall Space Flight center (MSFC), is tasked by NASA. The project is responsible for the development of an information system to support lunar exploration activities. It provides lunar explorers a set of tools and lunar map and model products that are predominantly derived from present lunar missions (e.g., the Lunar Reconnaissance Orbiter (LRO)) and from historical missions (e.g., Apollo). At Jet Propulsion Laboratory (JPL), we have built the LMMP interoperable geospatial information system's underlying infrastructure and a single point of entry - the LMMP Portal by employing a number of open standards and technologies. The Portal exposes a set of services to users to allow search, visualization, subset, and download of lunar data managed by the system. Users also have access to a set of tools that visualize, analyze and annotate the data. The infrastructure and Portal are based on web service oriented architecture. We designed the system to support solar system bodies in general including asteroids, earth and planets. We employed a combination of custom software, commercial and open-source components, off-the-shelf hardware and pay-by-use cloud computing services. The use of open standards and web service interfaces facilitate platform and application independent access to the services and data, offering for instances, iPad and Android mobile applications and large screen multi-touch with 3-D terrain viewing functions, for a rich browsing and analysis experience from a variety of platforms. The web services made use of open standards including: Representational State Transfer (REST); and Open Geospatial Consortium (OGC)'s Web Map Service (WMS), Web Coverage Service (WCS), Web Feature Service (WFS). Its data management services have been built on top of a set of open technologies including: Object Oriented Data Technology (OODT) - open source data catalog, archive, file management, data grid framework

Visibility of lunar surface features - Apollo 14 orbital observations and lunar landing.

Science.gov (United States)

Ziedman, K.

1972-01-01

Description of an in-flight visibility test conducted during the Apollo 14 mission for the purpose of validating and extending the mathematical visibility models used previously in the course of the Apollo program to examine the constraints on descent operations imposed by lunar visibility limitations. Following a background review of the effects on mission planning of the visibility limitations due to downsun lunar surface detail 'washout' and a discussion of the visibility prediction techniques previously used for studying lunar visibility problems, the visibility test rationale and procedures are defined and the test results presented. The results appear to confirm the validity of the visibility prediction techniques employed in lunar visibility problem studies. These results provide also a basis for improving the accuracy of the prediction techniques by appropriate modifications.

Lunar and interplanetary trajectories

CERN Document Server

Biesbroek, Robin

2016-01-01

This book provides readers with a clear description of the types of lunar and interplanetary trajectories, and how they influence satellite-system design. The description follows an engineering rather than a mathematical approach and includes many examples of lunar trajectories, based on real missions. It helps readers gain an understanding of the driving subsystems of interplanetary and lunar satellites. The tables and graphs showing features of trajectories make the book easy to understand. .

Lunar Water Resource Demonstration

Science.gov (United States)

Muscatello, Anthony C.

2008-01-01

In cooperation with the Canadian Space Agency, the Northern Centre for Advanced Technology, Inc., the Carnegie-Mellon University, JPL, and NEPTEC, NASA has undertaken the In-Situ Resource Utilization (ISRU) project called RESOLVE. This project is a ground demonstration of a system that would be sent to explore permanently shadowed polar lunar craters, drill into the regolith, determine what volatiles are present, and quantify them in addition to recovering oxygen by hydrogen reduction. The Lunar Prospector has determined these craters contain enhanced hydrogen concentrations averaging about 0.1%. If the hydrogen is in the form of water, the water concentration would be around 1%, which would translate into billions of tons of water on the Moon, a tremendous resource. The Lunar Water Resource Demonstration (LWRD) is a part of RESOLVE designed to capture lunar water and hydrogen and quantify them as a backup to gas chromatography analysis. This presentation will briefly review the design of LWRD and some of the results of testing the subsystem. RESOLVE is to be integrated with the Scarab rover from CMIJ and the whole system demonstrated on Mauna Kea on Hawaii in November 2008. The implications of lunar water for Mars exploration are two-fold: 1) RESOLVE and LWRD could be used in a similar fashion on Mars to locate and quantify water resources, and 2) electrolysis of lunar water could provide large amounts of liquid oxygen in LEO, leading to lower costs for travel to Mars, in addition to being very useful at lunar outposts.

LADEE LUNAR DUST EXPERIMENT

Data.gov (United States)

National Aeronautics and Space Administration — This archive bundle includes data taken by the Lunar Dust Experiment (LDEX) instrument aboard the Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft....

Assessment of source material (U and Th) in exploration, mining, processing of zircon sand in Central Kalimantan

International Nuclear Information System (INIS)

Dedi Hermawan; Pandu Dewanto; Sudarto

2011-01-01

From 2004 to 2008, according to data released by the Commerce Department, the volume of zircon sand and concentrates exports has increased highly. One of many locations in Indonesia that widely available zircon sand is Kalimantan island. For example, Central Kalimantan Province in 2007 to 2008 exports about 51,000 tones up to 79,000 tones of zircon sand annually. The concentration of source material in the zircon sand is important to be known because the presence of natural radioactive U and Th in zircon sand has the potential radiation hazard. Therefore it is necessary to conduct an assessment the potential reserves related to the source material contained in the zircon sand and radiation safety that are applied in the process of mining or processing of zircon sand. In this paper the location of mining and processing of zircon sand is restricted to the province of Central Kalimantan. From the assessment obtained that source material which is carried by zircon sand export form the province of Central Kalimantan have the potential to exceed the limits set by the BAPETEN Chairman Decree No.9 of 2006 About the Implementation of the Additional Protocol to the Accountability System and Control of Nuclear Materials. In terms of compliance with radiation safety, required increased surveillance of K3 during mining, process / processing by the worker, supervisor / supervisors and regional management company to be able the achievement of compliance with the provisions of the management of materials and the safety of radiation sources based on national regulations (BAPETEN) and international. (author)

Design and Construction of Manned Lunar Base

Science.gov (United States)

Li, Zhijie

2016-07-01

Building manned lunar base is one of the core aims of human lunar exploration project, which is also an important way to carry out the exploitation and utilization of lunar in situ resources. The most important part of manned lunar base is the design and construction of living habitation and many factors should be considered including science objective and site selection. Through investigating and research, the scientific goals of manned lunar base should be status and characteristics ascertainment of lunar available in situ resources, then developing necessary scientific experiments and utilization of lunar in situ resources by using special environment conditions of lunar surface. The site selection strategy of manned lunar base should rely on scientific goals according to special lunar surface environment and engineering capacity constraints, meanwhile, consulting the landing sites of foreign unmanned and manned lunar exploration, and choosing different typical regions of lunar surface and analyzing the landform and physiognomy, reachability, thermal environment, sunlight condition, micro meteoroids protection and utilization of in situ resources, after these steps, a logical lunar living habitation site should be confirmed. This paper brings out and compares three kinds of configurations with fabricating processes of manned lunar base, including rigid module, flexible and construction module manned lunar base. 1.The rigid habitation module is usually made by metal materials. The design and fabrication may consult the experience of space station, hence with mature technique. Because this configuration cannot be folded or deployed, which not only afford limit working and living room for astronauts, but also needs repetitious cargo transit between earth and moon for lunar base extending. 2. The flexible module habitation can be folded in fairing while launching. When deploying on moon, the configuration can be inflatable or mechanically-deployed, which means under

Development and mechanical properties of structural materials from lunar simulants

Science.gov (United States)

Desai, Chandra S.; Girdner, K.; Saadatmanesh, H.; Allen, T.

1991-01-01

Development of the technologies for manufacture of structural and construction materials on the Moon, utilizing local lunar soil (regolith), without the use of water, is an important element for habitats and explorations in space. Here, it is vital that the mechanical behavior such as strength and flexural properties, fracture toughness, ductility and deformation characteristics be defined toward establishment of the ranges of engineering applications of the materials developed. The objective is to describe the research results in two areas for the above goal: (1) liquefaction of lunar simulant (at about 100 C) with different additives (fibers, powders, etc.); and (2) development and use of a new triaxial test device in which lunar simulants are first compressed under cycles of loading, and then tested with different vacuums and initial confining or in situ stress.

Influence of the Choice of Lunar Gravity Model on Orbit Determination for Lunar Orbiters

Directory of Open Access Journals (Sweden)

Young-Rok Kim

2018-01-01

Full Text Available We examine the influence of the lunar gravity model on the orbit determination (OD of a lunar orbiter operating in a 100 km high, lunar polar orbit. Doppler and sequential range measurements by three Deep Space Network antennas and one Korea Deep Space Antenna were used. For measurement simulation and OD analysis, STK11 and ODTK6 were utilized. GLGM2, LP100K, LP150Q, GRAIL420A, and GRAIL660B were used for investigation of lunar gravity model selection effect. OD results were assessed by position and velocity uncertainties with error covariance and an external orbit comparison using simulated true orbit. The effect of the lunar gravity models on the long-term OD, degree and order level, measurement-acquisition condition, and lunar altitude was investigated. For efficiency verification, computational times for the five lunar gravity models were compared. Results showed that significant improvements to OD accuracy are observed by applying a GRAIL-based model; however, applying a full order and degree gravity modeling is not always the best strategy, owing to the computational burden. Consequently, we consider that OD using GRAIL660B with 70 × 70 degree and order is the most efficient strategy for mission preanalysis. This study provides useful guideline for KPLO OD analysis during nominal mission operation.

Researches on hazard avoidance cameras calibration of Lunar Rover

Science.gov (United States)

Li, Chunyan; Wang, Li; Lu, Xin; Chen, Jihua; Fan, Shenghong

2017-11-01

Lunar Lander and Rover of China will be launched in 2013. It will finish the mission targets of lunar soft landing and patrol exploration. Lunar Rover has forward facing stereo camera pair (Hazcams) for hazard avoidance. Hazcams calibration is essential for stereo vision. The Hazcam optics are f-theta fish-eye lenses with a 120°×120° horizontal/vertical field of view (FOV) and a 170° diagonal FOV. They introduce significant distortion in images and the acquired images are quite warped, which makes conventional camera calibration algorithms no longer work well. A photogrammetric calibration method of geometric model for the type of optical fish-eye constructions is investigated in this paper. In the method, Hazcams model is represented by collinearity equations with interior orientation and exterior orientation parameters [1] [2]. For high-precision applications, the accurate calibration model is formulated with the radial symmetric distortion and the decentering distortion as well as parameters to model affinity and shear based on the fisheye deformation model [3] [4]. The proposed method has been applied to the stereo camera calibration system for Lunar Rover.

Improvement of conditions for ceramics sintering on the base of lead zirconate-titanate

International Nuclear Information System (INIS)

Glinchuk, M.D.; Kim, P.V.; Bykov, I.P.; Lyashchenko, A.B.

1989-01-01

Lead zirconate-titanate powders of different graininess are studied for their phase composition. The finest grains of the powder consist of lead zirconate-titanate with the rhombohedral structure. Grains of 3-5 μm size are a mixture of lead zirconate-titanate and lead titanate, the latter exceeding 50% (by weight) causes the effect of anomalous expansion in the process of sintering. Control of the technological parameters of the synthesis permits producing powder with favourable correlation of the above phases and grain sizes. Sintering of such a powder induces no effect of the anomalous expansion with an increased density of the product attained

Prospective Ukrainian lunar orbiter mission

Science.gov (United States)

Shkuratov, Y.; Litvinenko, L.; Shulga, V.; Yatskiv, Y.; Kislyuk, V.

Ukraine has launch vehicles that are able to deliver about 300 kg to the lunar orbit. Future Ukrainian lunar program may propose a polar orbiter. This orbiter should fill principal information gaps in our knowledge about the Moon after Clementine and Lunar Prospector missions and the future missions, like Smart-1, Lunar-A, and Selene. We consider that this can be provided by radar studies of the Moon with supporting optical polarimetric observations from lunar polar orbit. These experiments allow one to better understand global structure of the lunar surface in a wide range of scales, from microns to kilometers. We propose three instruments for the prospective lunar orbiter. They are: a synthetic aperture imaging radar (SAR), ground-penetrating radar (GPR), and imaging polarimeter (IP). The main purpose of SAR is to study with high resolution (50 m) the permanently shadowed sites in the lunar polar regions. These sites are cold traps for volatiles, and have a potential of resource utilization. Possible presence of water ice in the regolith in the sites makes them interesting for permanent manned bases on the Moon. Radar imaging and mapping of other interesting regions could be also planned. Multi-frequencies multi-polarization soun d ing of the lunar surface with GPR can provide information about internal structure of the lunar surface from meters to several hundred meters deep. GPR can be used for measuring the megaregolith layer properties, detection of cryptomaria, and studies of internal structure of the largest craters. IP will be a CCD camera with an additional suite of polarizers. Modest spatial resolution (100 m) should provide a total coverage or a large portion of the lunar surface in oblique viewing basically at large phase angles. Polarization degree at large (>90°) phase angles bears information about characteristic size of the regolith particles. Additional radiophysical experiments are considered with the use of the SAR system, e.g., bistatic radar

The Lunar Source Disk: Old Lunar Datasets on a New CD-ROM

Science.gov (United States)

Hiesinger, H.

1998-01-01

A compilation of previously published datasets on CD-ROM is presented. This Lunar Source Disk is intended to be a first step in the improvement/expansion of the Lunar Consortium Disk, in order to create an "image-cube"-like data pool that can be easily accessed and might be useful for a variety of future lunar investigations. All datasets were transformed to a standard map projection that allows direct comparison of different types of information on a pixel-by pixel basis. Lunar observations have a long history and have been important to mankind for centuries, notably since the work of Plutarch and Galileo. As a consequence of centuries of lunar investigations, knowledge of the characteristics and properties of the Moon has accumulated over time. However, a side effect of this accumulation is that it has become more and more complicated for scientists to review all the datasets obtained through different techniques, to interpret them properly, to recognize their weaknesses and strengths in detail, and to combine them synoptically in geologic interpretations. Such synoptic geologic interpretations are crucial for the study of planetary bodies through remote-sensing data in order to avoid misinterpretation. In addition, many of the modem datasets, derived from Earth-based telescopes as well as from spacecraft missions, are acquired at different geometric and radiometric conditions. These differences make it challenging to compare or combine datasets directly or to extract information from different datasets on a pixel-by-pixel basis. Also, as there is no convention for the presentation of lunar datasets, different authors choose different map projections, depending on the location of the investigated areas and their personal interests. Insufficient or incomplete information on the map parameters used by different authors further complicates the reprojection of these datasets to a standard geometry. The goal of our efforts was to transfer previously published lunar

Mechanical properties of lunar regolith and lunar soil simulant

Science.gov (United States)

Perkins, Steven W.

1989-01-01

Through the Surveyor 3 and 7, and Apollo 11-17 missions a knowledge of the mechanical properties of Lunar regolith were gained. These properties, including material cohesion, friction, in-situ density, grain-size distribution and shape, and porosity, were determined by indirect means of trenching, penetration, and vane shear testing. Several of these properties were shown to be significantly different from those of terrestrial soils, such as an interlocking cohesion and tensile strength formed in the absence of moisture and particle cementation. To characterize the strength and deformation properties of Lunar regolith experiments have been conducted on a lunar soil simulant at various initial densities, fabric arrangements, and composition. These experiments included conventional triaxial compression and extension, direct tension, and combined tension-shear. Experiments have been conducted at low levels of effective confining stress. External conditions such as membrane induced confining stresses, end platten friction and material self weight have been shown to have a dramatic effect on the strength properties at low levels of confining stress. The solution has been to treat these external conditions and the specimen as a full-fledged boundary value problem rather than the idealized elemental cube of mechanics. Centrifuge modeling allows for the study of Lunar soil-structure interaction problems. In recent years centrifuge modeling has become an important tool for modeling processes that are dominated by gravity and for verifying analysis procedures and studying deformation and failure modes. Centrifuge modeling is well established for terrestrial enginering and applies equally as well to Lunar engineering. A brief review of the experiments is presented in graphic and outline form.

Extrapolation of zircon fission-track annealing models

International Nuclear Information System (INIS)

Palissari, R.; Guedes, S.; Curvo, E.A.C.; Moreira, P.A.F.P.; Tello, C.A.; Hadler, J.C.

2013-01-01

One of the purposes of this study is to give further constraints on the temperature range of the zircon partial annealing zone over a geological time scale using data from borehole zircon samples, which have experienced stable temperatures for ∼1 Ma. In this way, the extrapolation problem is explicitly addressed by fitting the zircon annealing models with geological timescale data. Several empirical model formulations have been proposed to perform these calibrations and have been compared in this work. The basic form proposed for annealing models is the Arrhenius-type model. There are other annealing models, that are based on the same general formulation. These empirical model equations have been preferred due to the great number of phenomena from track formation to chemical etching that are not well understood. However, there are two other models, which try to establish a direct correlation between their parameters and the related phenomena. To compare the response of the different annealing models, thermal indexes, such as closure temperature, total annealing temperature and the partial annealing zone, have been calculated and compared with field evidence. After comparing the different models, it was concluded that the fanning curvilinear models yield the best agreement between predicted index temperatures and field evidence. - Highlights: ► Geological data were used along with lab data for improving model extrapolation. ► Index temperatures were simulated for testing model extrapolation. ► Curvilinear Arrhenius models produced better geological temperature predictions

Mineralogical and chemical properties of the lunar regolith

Science.gov (United States)

Mckay, David S.; Ming, Douglas W.

1989-01-01

The composition of lunar regolith and its attendant properties are discussed. Tables are provided listing lunar minerals, the abundance of plagioclase feldspar, pyroxene, olivine, and ilmenite in lunar materials, typical compositions of common lunar minerals, and cumulative grain-size distribution for a large number of lunar soils. Also provided are charts on the chemistry of breccias, the chemistry of lunar glass, and the comparative chemistry of surface soils for the Apollo sites. Lunar agglutinates, constructional particles made of lithic, mineral, and glass fragments welded together by a glassy matrix containing extremely fine-grained metallic iron and formed by micrometeoric impacts at the lunar surface, are discussed. Crystalline, igneous rock fragments, breccias, and lunar glass are examined. Volatiles implanted in lunar materials and regolith maturity are also addressed.

Detection of the lunar body tide by the Lunar Orbiter Laser Altimeter.

Science.gov (United States)

Mazarico, Erwan; Barker, Michael K; Neumann, Gregory A; Zuber, Maria T; Smith, David E

2014-04-16

The Lunar Orbiter Laser Altimeter instrument onboard the Lunar Reconnaissance Orbiter spacecraft collected more than 5 billion measurements in the nominal 50 km orbit over ∼10,000 orbits. The data precision, geodetic accuracy, and spatial distribution enable two-dimensional crossovers to be used to infer relative radial position corrections between tracks to better than ∼1 m. We use nearly 500,000 altimetric crossovers to separate remaining high-frequency spacecraft trajectory errors from the periodic radial surface tidal deformation. The unusual sampling of the lunar body tide from polar lunar orbit limits the size of the typical differential signal expected at ground track intersections to ∼10 cm. Nevertheless, we reliably detect the topographic tidal signal and estimate the associated Love number h 2 to be 0.0371 ± 0.0033, which is consistent with but lower than recent results from lunar laser ranging. Altimetric data are used to create radial constraints on the tidal deformationThe body tide amplitude is estimated from the crossover dataThe estimated Love number is consistent with previous estimates but more precise.

Summary of the results from the lunar orbiter laser altimeter after seven years in lunar orbit

Science.gov (United States)

Smith, David E.; Zuber, Maria T.; Neumann, Gregory A.; Mazarico, Erwan; Lemoine, Frank G.; Head, James W., III; Lucey, Paul G.; Aharonson, Oded; Robinson, Mark S.; Sun, Xiaoli; Torrence, Mark H.; Barker, Michael K.; Oberst, Juergen; Duxbury, Thomas C.; Mao, Dandan; Barnouin, Olivier S.; Jha, Kopal; Rowlands, David D.; Goossens, Sander; Baker, David; Bauer, Sven; Gläser, Philipp; Lemelin, Myriam; Rosenburg, Margaret; Sori, Michael M.; Whitten, Jennifer; Mcclanahan, Timothy

2017-02-01

In June 2009 the Lunar Reconnaissance Orbiter (LRO) spacecraft was launched to the Moon. The payload consists of 7 science instruments selected to characterize sites for future robotic and human missions. Among them, the Lunar Orbiter Laser Altimeter (LOLA) was designed to obtain altimetry, surface roughness, and reflectance measurements. The primary phase of lunar exploration lasted one year, following a 3-month commissioning phase. On completion of its exploration objectives, the LRO mission transitioned to a science mission. After 7 years in lunar orbit, the LOLA instrument continues to map the lunar surface. The LOLA dataset is one of the foundational datasets acquired by the various LRO instruments. LOLA provided a high-accuracy global geodetic reference frame to which past, present and future lunar observations can be referenced. It also obtained high-resolution and accurate global topography that were used to determine regions in permanent shadow at the lunar poles. LOLA further contributed to the study of polar volatiles through its unique measurement of surface brightness at zero phase, which revealed anomalies in several polar craters that may indicate the presence of water ice. In this paper, we describe the many LOLA accomplishments to date and its contribution to lunar and planetary science.

Summary of the Results from the Lunar Orbiter Laser Altimeter after Seven Years in Lunar Orbit

Science.gov (United States)

Smith, David E.; Zuber, Maria T.; Neumann, Gregory A.; Mazarico, Erwan; Lemoine, Frank G.; Head, James W., III; Lucey, Paul G.; Aharonson, Oded; Robinson, Mark S.; Sun, Xiaoli;

Man-Made Debris In and From Lunar Orbit

Science.gov (United States)

Johnson, Nicholas L.; McKay, Gordon A. (Technical Monitor)

1999-01-01

During 1966-1976, as part of the first phase of lunar exploration, 29 manned and robotic missions placed more than 40 objects into lunar orbit. Whereas several vehicles later successfully landed on the Moon and/or returned to Earth, others were either abandoned in orbit or intentionally sent to their destruction on the lunar surface. The former now constitute a small population of lunar orbital debris; the latter, including four Lunar Orbiters and four Lunar Module ascent stages, have contributed to nearly 50 lunar sites of man's refuse. Other lunar satellites are known or suspected of having fallen from orbit. Unlike Earth satellite orbital decays and deorbits, lunar satellites impact the lunar surface unscathed by atmospheric burning or melting. Fragmentations of lunar satellites, which would produce clouds of numerous orbital debris, have not yet been detected. The return to lunar orbit in the 1990's by the Hagoromo, Hiten, Clementine, and Lunar Prospector spacecraft and plans for increased lunar exploration early in the 21st century, raise questions of how best to minimize and to dispose of lunar orbital debris. Some of the lessons learned from more than 40 years of Earth orbit exploitation can be applied to the lunar orbital environment. For the near-term, perhaps the most important of these is postmission passivation. Unique solutions, e.g., lunar equatorial dumps, may also prove attractive. However, as with Earth satellites, debris mitigation measures are most effectively adopted early in the concept and design phase, and prevention is less costly than remediation.

Going back in time with zircon

International Nuclear Information System (INIS)

Burger, A.; Faurie, J.

1978-01-01

Uranium-lead age dating, with zircon as the agent is the most recent advance in exploring rocks and minerals to define their stratigraphic sequence. The authors believe it will have a tremendous effect on the accurate mapping of the earth's mineral resources, including those of Antartica; indeed, even of the moon

Synthesis, Characterization and Thermal Diffusivity of Holmium and Praseodymium Zirconates

OpenAIRE

Stopyra M.; Niemiec D.; Moskal G.

2016-01-01

A2B2O7 oxides with pyrochlore or defected fluorite structure are among the most promising candidates for insulation layer material in thermal barrier coatings. The present paper presents the procedure of synthesis of holmium zirconate Ho2Zr2O7 and praseodymium zirconate Pr2Zr2O7 via Polymerized-Complex Method (PCM). Thermal analysis of precursor revealed that after calcination at relatively low temperature (700°C) fine-crystalline, single-phase material is obtained. Thermal diffusivity was me...

Lunar Navigation Architecture Design Considerations

Science.gov (United States)

D'Souza, Christopher; Getchius, Joel; Holt, Greg; Moreau, Michael

2009-01-01

The NASA Constellation Program is aiming to establish a long-term presence on the lunar surface. The Constellation elements (Orion, Altair, Earth Departure Stage, and Ares launch vehicles) will require a lunar navigation architecture for navigation state updates during lunar-class missions. Orion in particular has baselined earth-based ground direct tracking as the primary source for much of its absolute navigation needs. However, due to the uncertainty in the lunar navigation architecture, the Orion program has had to make certain assumptions on the capabilities of such architectures in order to adequately scale the vehicle design trade space. The following paper outlines lunar navigation requirements, the Orion program assumptions, and the impacts of these assumptions to the lunar navigation architecture design. The selection of potential sites was based upon geometric baselines, logistical feasibility, redundancy, and abort support capability. Simulated navigation covariances mapped to entry interface flightpath- angle uncertainties were used to evaluate knowledge errors. A minimum ground station architecture was identified consisting of Goldstone, Madrid, Canberra, Santiago, Hartebeeshoek, Dongora, Hawaii, Guam, and Ascension Island (or the geometric equivalent).

Zircon reveals protracted magma storage and recycling beneath Mount St. Helens

Science.gov (United States)

Claiborne, L.L.; Miller, C.F.; Flanagan, D.M.; Clynne, M.A.; Wooden, J.L.

2010-01-01

Current data and models for Mount St. Helens volcano (Washington, United States) suggest relatively rapid transport from magma genesis to eruption, with no evidence for protracted storage or recycling of magmas. However, we show here that complex zircon age populations extending back hundreds of thousands of years from eruption age indicate that magmas regularly stall in the crust, cool and crystallize beneath the volcano, and are then rejuvenated and incorporated by hotter, young magmas on their way to the surface. Estimated dissolution times suggest that entrained zircon generally resided in rejuvenating magmas for no more than about a century. Zircon elemental compositions reflect the increasing influence of mafic input into the system through time, recording growth from hotter, less evolved magmas tens of thousands of years prior to the appearance of mafic magmas at the surface, or changes in whole-rock geochemistry and petrology, and providing a new, time-correlated record of this evolution independent of the eruption history. Zircon data thus reveal the history of the hidden, long-lived intrusive portion of the Mount St. Helens system, where melt and crystals are stored for as long as hundreds of thousands of years and interact with fresh influxes of magmas that traverse the intrusive reservoir before erupting. ?? 2010 Geological Society of America.

Phase transformations in lead zirconate-titanate doped with lanthanum

Energy Technology Data Exchange (ETDEWEB)

Ishchuk, V M; Morozov, E M

1979-07-01

Presented are the results of studies on the character of phase transitions of the lead-lanthanum zirconate-titanate (LLZT) system. The replacement of lead by lanthanum leads to the expansion of the region of antisegnetoelectric (ASE) states of solid solutions of lead zirconate-titanate (LZT) in the direction of PbTiO/sub 3/ concentration growth. An intermediate region is revealed between segnetoelectric (SE) and ASE states, material properties in which depend on their prehistory: annealed samples are in the ASE state, whereas the application of electric field exceeding some critical value induces the SE state. A family of phase diagrams obtained at consequent replacement of lead by lanthanum permits to identify phase states in any series of LLZT with a constant ratio of Zr:Ti, in the x/65/35 series in particular. Thermally depolarized state of materials of this series at x<6.5 is shown to be antisegnetoelectric at all the temperatures below the Curie point Tsub(c), and heating causes phase transition of ASE..-->..PE (paraelectric state) at Tsub(c). Polarized samples being heated, a successiveness of phase transitions of SE..-->..ASE takes place at T/sub 0/, and that of ASE reversible PE at Tsub(C) (Tsub(0)..ASE phase transition in the LZT system.

Enhanced provenance interpretation using combined U-Pb and (U-Th)/He double dating of detrital zircon grains from lower Miocene strata, proximal Gulf of Mexico Basin, North America

Science.gov (United States)

Xu, Jie; Stockli, Daniel F.; Snedden, John W.

2017-10-01

Detrital zircon U-Pb analysis is an effective approach for investigating sediment provenance by relating crystallization age to potential crystalline source terranes. Studies of large passive margin basins, such as the Gulf of Mexico Basin, that have received sediment from multiple terranes with non-unique crystallization ages or sedimentary strata, benefit from additional constraints to better elucidate provenance interpretation. In this study, U-Pb and (U-Th)/He double dating analyses on single zircons from the lower Miocene sandstones in the northern Gulf of Mexico Basin reveal a detailed history of sediment source evolution. U-Pb age data indicate that most zircon originated from five major crystalline provinces, including the Western Cordillera Arc (1800 Ma) terranes. Zircon (U-Th)/He ages record tectonic cooling and exhumation in the U.S. since the Mesoproterozoic related to the Grenville to Laramide Orogenies. The combined crystallization and cooling information from single zircon double dating can differentiate volcanic and plutonic zircons. Importantly, the U-Pb-He double dating approach allows for the differentiation between multiple possible crystallization-age sources on the basis of their subsequent tectonic evolution. In particular, for Grenville zircons that are present in all of lower Miocene samples, four distinct zircon U-Pb-He age combinations are recognizable that can be traced back to four different possible sources. The integrated U-Pb and (U-Th)/He data eliminate some ambiguities and improves the provenance interpretation for the lower Miocene strata in the northern Gulf of Mexico Basin and illustrate the applicability of this approach for other large-scale basins to reconstruct sediment provenance and dispersal patterns.

The new lunar ephemeris INPOP17a and its application to fundamental physics

Science.gov (United States)

Viswanathan, V.; Fienga, A.; Minazzoli, O.; Bernus, L.; Laskar, J.; Gastineau, M.

2018-05-01

We present here the new INPOP lunar ephemeris, INPOP17a. This ephemeris is obtained through the numerical integration of the equations of motion and of rotation of the Moon, fitted over 48 yr of lunar laser ranging (LLR) data. We also include the 2 yr of infrared LLR data acquired at the Grasse station between 2015 and 2017. Tests of the universality of free-fall are performed. We find no violation of the principle of equivalence at the (-3.8 ± 7.1) × 10-14 level. A new interpretation in the frame of dilaton theories is also proposed.

Data Analysis Techniques for a Lunar Surface Navigation System Testbed

Science.gov (United States)

Chelmins, David; Sands, O. Scott; Swank, Aaron

2011-01-01

NASA is interested in finding new methods of surface navigation to allow astronauts to navigate on the lunar surface. In support of the Vision for Space Exploration, the NASA Glenn Research Center developed the Lunar Extra-Vehicular Activity Crewmember Location Determination System and performed testing at the Desert Research and Technology Studies event in 2009. A significant amount of sensor data was recorded during nine tests performed with six test subjects. This paper provides the procedure, formulas, and techniques for data analysis, as well as commentary on applications.

Lunar regolith stratigraphy analysis based on the simulation of lunar penetrating radar signals

Science.gov (United States)

Lai, Jialong; Xu, Yi; Zhang, Xiaoping; Tang, Zesheng

2017-11-01

The thickness of lunar regolith is an important index of evaluating the quantity of lunar resources such as 3He and relative geologic ages. Lunar penetrating radar (LPR) experiment of Chang'E-3 mission provided an opportunity of in situ lunar subsurface structure measurement in the northern mare imbrium area. However, prior work on analyzing LPR data obtained quite different conclusions of lunar regolith structure mainly because of the missing of clear interface reflectors in radar image. In this paper, we utilized finite-difference time-domain (FDTD) method and three models of regolith structures with different rock density, number of layers, shapes of interfaces, and etc. to simulate the LPR signals for the interpretation of radar image. The simulation results demonstrate that the scattering signals caused by numerous buried rocks in the regolith can mask the horizontal reflectors, and the die-out of radar echo does not indicate the bottom of lunar regolith layer and data processing such as migration method could recover some of the subsurface information but also result in fake signals. Based on analysis of simulation results, we conclude that LPR results uncover the subsurface layered structure containing the rework zone with multiple ejecta blankets of small crater, the ejecta blanket of Chang'E-3 crater, and the transition zone and estimate the thickness of the detected layer is about 3.25 m.

Multi-state autonomous drilling for lunar exploration

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Chen Chongbin

2016-10-01

Full Text Available Due to the lack of information of subsurface lunar regolith stratification which varies along depth, the drilling device may encounter lunar soil and lunar rock randomly in the drilling process. To meet the load safety requirements of unmanned sampling mission under limited orbital resources, the control strategy of autonomous drilling should adapt to the indeterminable lunar environments. Based on the analysis of two types of typical drilling media (i.e., lunar soil and lunar rock, this paper proposes a multi-state control strategy for autonomous lunar drilling. To represent the working circumstances in the lunar subsurface and reduce the complexity of the control algorithm, lunar drilling process was categorized into three drilling states: the interface detection, initiation of drilling parameters for recognition and drilling medium recognition. Support vector machine (SVM and continuous wavelet transform were employed for the online recognition of drilling media and interface, respectively. Finite state machine was utilized to control the transition among different drilling states. To verify the effectiveness of the multi-state control strategy, drilling experiments were implemented with multi-layered drilling media constructed by lunar soil simulant and lunar rock simulant. The results reveal that the multi-state control method is capable of detecting drilling state variation and adjusting drilling parameters timely under vibration interferences. The multi-state control method provides a feasible reference for the control of extraterrestrial autonomous drilling.

Critical Robotic Lunar Missions

Science.gov (United States)

Plescia, J. B.

2018-04-01

Perhaps the most critical missions to understanding lunar history are in situ dating and network missions. These would constrain the volcanic and thermal history and interior structure. These data would better constrain lunar evolution models.

Lunar base thermoelectric power station study

Science.gov (United States)

Determan, William; Frye, Patrick; Mondt, Jack; Fleurial, Jean-Pierre; Johnson, Ken; Stapfer, G.; Brooks, Michael D.; Heshmatpour, Ben

2006-01-01

Under NASA's Project Prometheus, the Nuclear Systems Program, the Jet Propulsion Laboratory, Pratt & Whitney Rocketdyne, and Teledyne Energy Systems have teamed with a number of universities, under the Segmented Thermoelectric Multicouple Converter (STMC) program, to develop the next generation of advanced thermoelectric converters for space reactor power systems. Work on the STMC converter assembly has progressed to the point where the lower temperature stage of the segmented multicouple converter assembly is ready for laboratory testing and the upper stage materials have been identified and their properties are being characterized. One aspect of the program involves mission application studies to help define the potential benefits from the use of these STMC technologies for designated NASA missions such as the lunar base power station where kilowatts of power are required to maintain a permanent manned presence on the surface of the moon. A modular 50 kWe thermoelectric power station concept was developed to address a specific set of requirements developed for this mission. Previous lunar lander concepts had proposed the use of lunar regolith as in-situ radiation shielding material for a reactor power station with a one kilometer exclusion zone radius to minimize astronaut radiation dose rate levels. In the present concept, we will examine the benefits and requirements for a hermetically-sealed reactor thermoelectric power station module suspended within a man-made lunar surface cavity. The concept appears to maximize the shielding capabilities of the lunar regolith while minimizing its handling requirements. Both thermal and nuclear radiation levels from operation of the station, at its 100-m exclusion zone radius, were evaluated and found to be acceptable. Site preparation activities are reviewed and well as transport issues for this concept. The goal of the study was to review the entire life cycle of the unit to assess its technical problems and technology

Apollo Missions to the Lunar Surface

Science.gov (United States)

Graff, Paige V.

2018-01-01

Six Apollo missions to the Moon, from 1969-1972, enabled astronauts to collect and bring lunar rocks and materials from the lunar surface to Earth. Apollo lunar samples are curated by NASA Astromaterials at the NASA Johnson Space Center in Houston, TX. Samples continue to be studied and provide clues about our early Solar System. Learn more and view collected samples at: https://curator.jsc.nasa.gov/lunar.

Optimal Lunar Landing Trajectory Design for Hybrid Engine

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Dong-Hyun Cho

2015-01-01

Full Text Available The lunar landing stage is usually divided into two parts: deorbit burn and powered descent phases. The optimal lunar landing problem is likely to be transformed to the trajectory design problem on the powered descent phase by using continuous thrusters. The optimal lunar landing trajectories in general have variety in shape, and the lunar lander frequently increases its altitude at the initial time to obtain enough time to reduce the horizontal velocity. Due to the increment in the altitude, the lunar lander requires more fuel for lunar landing missions. In this work, a hybrid engine for the lunar landing mission is introduced, and an optimal lunar landing strategy for the hybrid engine is suggested. For this approach, it is assumed that the lunar lander retrofired the impulsive thruster to reduce the horizontal velocity rapidly at the initiated time on the powered descent phase. Then, the lunar lander reduced the total velocity and altitude for the lunar landing by using the continuous thruster. In contradistinction to other formal optimal lunar landing problems, the initial horizontal velocity and mass are not fixed at the start time. The initial free optimal control theory is applied, and the optimal initial value and lunar landing trajectory are obtained by simulation studies.

Lunar Exploration Missions Since 2006

Science.gov (United States)

Lawrence, S. J. (Editor); Gaddis, L. R.; Joy, K. H.; Petro, N. E.

2017-01-01

The announcement of the Vision for Space Exploration in 2004 sparked a resurgence in lunar missions worldwide. Since the publication of the first "New Views of the Moon" volume, as of 2017 there have been 11 science-focused missions to the Moon. Each of these missions explored different aspects of the Moon's geology, environment, and resource potential. The results from this flotilla of missions have revolutionized lunar science, and resulted in a profoundly new emerging understanding of the Moon. The New Views of the Moon II initiative itself, which is designed to engage the large and vibrant lunar science community to integrate the results of these missions into new consensus viewpoints, is a direct outcome of this impressive array of missions. The "Lunar Exploration Missions Since 2006" chapter will "set the stage" for the rest of the volume, introducing the planetary community at large to the diverse array of missions that have explored the Moon in the last decade. Content: This chapter will encompass the following missions: Kaguya; ARTEMIS (Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon’s Interaction with the Sun); Chang’e-1; Chandrayaan-1; Moon Impact Probe; Lunar Reconnaissance Orbiter (LRO); Lunar Crater Observation Sensing Satellite (LCROSS); Chang’e-2; Gravity Recovery and Interior Laboratory (GRAIL); Lunar Atmosphere and Dust Environment Explorer (LADEE); Chang’e-3.

Elemental and Isotopic Tomography at Single-Atom-Scale in 4.0 and 2.4 Ga Zircons

Science.gov (United States)

Valley, J. W.; Reinhard, D. A.; Snoeyenbos, D.; Lawrence, D.; Martin, I.; Kelly, T. F.; Ushikubo, T.; Strickland, A.; Cavosie, A. J.

2012-12-01

Atom probe tomography can determine identity (mass/charge ratio) and 3-D position of individual atoms in minerals such as zircon. These data provide unique information for understanding the thermal history and mechanisms of mineral reaction and exchange, including radiation damage. Nine needle-shaped specimens ~100 nm in diameter (at the apex) were sampled from 2 zircons by FIB and analyzed with a local-electrode atom probe (LEAP), CAMECA LEAP 4000X HR. The LEAP uses pulsed-laser heating to field evaporate the tip of a zircon needle and accelerates the ions into a position-sensitive TOF-MS. With due care for complex isobaric interferences (molecules, multiple ionizations) and background correction, it is possible to individually identify up to 10E8 atoms/needle (36% detection efficiency) by mass/charge (MRP ~ 1000@ m/n=16Da) and position (X-Y-Z coordinates on 0.2 nm scale) (Kelly & Larson 2012). The 3-D distribution of Pb and Y differ at atom-scale in the 2 zircons. Zircon #1 (4007 Ma, Jack Hills, W. Australia, Cavosie 2005, Ushikubo et al. 2008, Bouvier et al. 2011) is homogeneous in Pb and Y. In contrast, incompatible elements, including Pb and Y, are concentrated in equant 5-10 nm dia. domains, spaced ~50 nm apart in zircon #2 (2438 Ma, Albion-Raft R-Grouse Ck core complex, Utah, Strickland et al. 2011). U is homogeneously distributed in both zircons. The analyzed domains suffered 4-8 x 10E15 α-decay events/mg due to U and Th decay and yet both zircons yield >97% concordant U-Pb ages by SIMS, suggesting annealing of radiation damage during the life of the zircons. The 207-Pb/206-Pb ratios for these nm-scale domains, as measured by LEAP, average 0.17 for the 2.4 Ga Zrc2 (3 needles) and 0.43 for the 4.0 Ga Zrc1 (5 needles). These ratios are less precise (±40% 2σ) due to ultra-small sample size, but are in excellent agreement with values measured by SIMS, 0.1684 and 0.4269, respectively. Thus Pb in both zircons is radiogenic. The Pb-Y-rich domains and lack of

The ESA Lunar Lander and the search for Lunar Volatiles

Science.gov (United States)

Morse, A. D.; Barber, S. J.; Pillinger, J. M.; Sheridan, S.; Wright, I. P.; Gibson, E. K.; Merrifield, J. A.; Waltham, N. R.; Waugh, L. J.; Pillinger, C. T.

2011-10-01

Following the Apollo era the moon was considered a volatile poor body. Samples collected from the Apollo missions contained only ppm levels of water formed by the interaction of the solar wind with the lunar regolith [1]. However more recent orbiter observations have indicated that water may exist as water ice in cold polar regions buried within craters at concentrations of a few wt. % [2]. Infrared images from M3 on Chandrayaan-1 have been interpreted as showing the presence of hydrated surface minerals with the ongoing hydroxyl/water process feeding cold polar traps. This has been supported by observation of ephemeral features termed "space dew" [3]. Meanwhile laboratory studies indicate that water could be present in appreciable quantities in lunar rocks [4] and could also have a cometary source [5]. The presence of sufficient quantities of volatiles could provide a resource which would simplify logistics for long term lunar missions. The European Space Agency (ESA's Directorate of Human Spaceflight and Operations) have provisionally scheduled a robotic mission to demonstrate key technologies to enable later human exploration. Planned for launch in 2018, the primary aim is for precise automated landing, with hazard avoidance, in zones which are almost constantly illuminated (e.g. at the edge of the Shackleton crater at the lunar south pole). These regions would enable the solar powered Lander to survive for long periods > 6 months, but require accurate navigation to within 200m. Although landing in an illuminated area, these regions are close to permanently shadowed volatile rich regions and the analysis of volatiles is a major science objective of the mission. The straw man payload includes provision for a Lunar Volatile and Resources Analysis Package (LVRAP). The authors have been commissioned by ESA to conduct an evaluation of possible technologies to be included in L-VRAP which can be included within the Lander payload. Scientific aims are to demonstrate the

Application of Apollo cosmic radiation dosimetry to lunar colonization studies

International Nuclear Information System (INIS)

English, R.A.; Bailey, J.V.; Brown, R.D.

1972-01-01

The radiation data gathered from the lunar landing missions of Apollo 11 through Apollo 15 are presented. These data have been analyzed to provide dosimetry evaluation of the ambient radiation and radiation from potential solar particle events for the planning of safe, long-term stays of relatively large numbers of individuals upon the moon. (U.S.)

What is a lunar standstill III?

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Lionel Duke Sims

2016-12-01

Full Text Available Prehistoric monument alignments on lunar standstills are currently understood for horizon range, perturbation event, crossover event, eclipse prediction, solstice full Moon and the solarisation of the dark Moon. The first five models are found to fail the criteria of archaeoastronomy field methods. The final model of lunar-solar conflation draws upon all the observed components of lunar standstills – solarised reverse phased sidereal Moons culminating in solstice dark Moons in a roughly nine-year alternating cycle between major and minor standstills. This lunar-solar conflation model is a syncretic overlay upon an antecedent Palaeolithic template for lunar scheduled rituals and amenable to transformation.

The first discovery of Hadean zircon in garnet granulites from the Sutam River (Aldan Shield)

Science.gov (United States)

Glukhovskii, M. Z.; Kuz'min, M. I.; Bayanova, T. B.; Lyalina, L. M.; Makrygina, V. A.; Shcherbakova, T. F.

2017-09-01

For the first time in Russia, a Hadean zircon grain with an age of 3.94 Ga (ID-TIMS) has been discovered in high-aluminous garnet granulites of the Aldan Shield among the U-Pb zircons with an age from 1.92 Ga. In this connection, the problems of its parental source, the petrogenesis of granulites that captured this zircon, and the mechanism of occurrence of these deep rocks in the upper horizons of the crust have been solved. The comparison of the geochemistry of garnet granulites and the middle crust has shown that the granulites are enriched in the entire range of rare-earth elements (except for the Eu minimum), as well as in Al2O3, U, and Th and are depleted in the most mobile elements (Na, Ca, Sr). In the upper part of the allitic weathering zone of the middle crust, which formed under conditions of arid climate, this zircon grain was originated from the weathered granites from the middle crust. In the latter case, they were empleced discretely in the upper granite-gneiss crust under high pressure conditions (the rutile age is 1.83-1.82 Ga). The zircon with an age of 3.94 Ga is comparable to the Hadean zircons from orthogneisses of the Acasta region (Canadian Shield, 4.03-3.94 Ga).

A long-lived lunar dynamo driven by continuous mechanical stirring.

Science.gov (United States)

Dwyer, C A; Stevenson, D J; Nimmo, F

2011-11-09

Lunar rocks contain a record of an ancient magnetic field that seems to have persisted for more than 400 million years and which has been attributed to a lunar dynamo. Models of conventional dynamos driven by thermal or compositional convection have had difficulty reproducing the existence and apparently long duration of the lunar dynamo. Here we investigate an alternative mechanism of dynamo generation: continuous mechanical stirring arising from the differential motion, due to Earth-driven precession of the lunar spin axis, between the solid silicate mantle and the liquid core beneath. We show that the fluid motions and the power required to drive a dynamo operating continuously for more than one billion years and generating a magnetic field that had an intensity of more than one microtesla 4.2 billion years ago are readily obtained by mechanical stirring. The magnetic field is predicted to decrease with time and to shut off naturally when the Moon recedes far enough from Earth that the dissipated power is insufficient to drive a dynamo; in our nominal model, this occurred at about 48 Earth radii (2.7 billion years ago). Thus, lunar palaeomagnetic measurements may be able to constrain the poorly known early orbital evolution of the Moon. This mechanism may also be applicable to dynamos in other bodies, such as large asteroids.

Simulated Lunar Testing of Metabolic Heat Regenerated Temperature Swing Adsorption

Science.gov (United States)

Padilla, Sebastian A.; Bower, Chad E.; Iacomini, Christie S.; Paul, Heather L.

2012-01-01

Metabolic heat regenerated Temperature Swing Adsorption (MTSA) technology is being developed for thermal and carbon dioxide (CO2) control for a Portable Life Support System (PLSS), as well as water recycling. An Engineering Development Unit (EDU) of the MTSA Subassembly (MTSAS) was designed and assembled for optimized Martian operations, but also meets system requirements for lunar operations. For lunar operations the MTSA sorption cycle is driven via a vacuum swing between suit ventilation loop pressure and lunar vacuum. The focus of this effort was testing in a simulated lunar environment. This environment was simulated in Paragon's EHF vacuum chamber. The objective of the testing was to evaluate the full cycle performance of the MTSA Subassembly EDU, and to assess CO2 loading and pressure drop of the wash coated aluminum reticulated foam sorbent bed. Lunar environment testing proved out the feasibility of pure vacuum swing operation, making MTSA a technology that can be tested and used on the Moon prior to going to Mars. Testing demonstrated better than expected CO2 Nomenclature loading on the sorbent and nearly replicates the equilibrium data from the sorbent manufacturer. This exceeded any of the previous sorbent loading tests performed by Paragon. Subsequently, the increased performance of the sorbent bed design indicates future designs will require less mass and volume than the current EDU rendering MTSA as very competitive for Martian PLSS applications.

Study of nanoconfigurations in Zircon-Mullite composites using perturbed angular correlations

Energy Technology Data Exchange (ETDEWEB)

Chain, Cecilia Y., E-mail: yamil@fisica.unlp.edu.ar; Pasquevich, Alberto F. [Universidad Nacional de La Plata, Departamento de Fisica, IFLP, Facultad de Ciencias Exactas (Argentina); Rivas, Patricia C. [CONICET (Argentina); Martinez, Jorge A.; Caracoche, Maria C. [Universidad Nacional de La Plata, Departamento de Fisica, IFLP, Facultad de Ciencias Exactas (Argentina); Rendtorff, Nicolas M. [CONICET (Argentina); Conconi, Maria S. [Centro de Tecnologia de Recursos Minerales y Ceramica (CETMIC: CONICET-CIC) (Argentina); Aglietti, Esteban F. [CONICET (Argentina)

2010-06-15

It has been already published that, at nanoscopic level, zircon exhibits wide regions of aperiodic material not detected by the ordinary techniques used to analyse the obtained product in the production of ceramic materials. In this paper it is reported how the Perturbed Angular Correlations (PAC) technique has assisted the interpretation of a mismatch between experiment and theoretical estimation of a mechanical property in some zircon-mullite composites. In fact, it has been proved that the difference observed between the calculated and the experimental value of the elastic modulus in composites of the form (1-x) ZrSiO{sub 4} - x 3Al{sub 2}O{sub 3}.2SiO{sub 2} (with x = 15, 25, 35 and 45 wt.%) behaves very similarly as the relative amount of aperiodic zircon determined by PAC. This result allows to re-interpret the mullite role during the materials preparation.

SHRIMP U-Pb dating of detrital zircons in metamorphic rocks from northern Kyushu, western Japan

International Nuclear Information System (INIS)

Tsutsumi, Yukiyasu; Yokoyama, Kazumi; Terada, Kentaro; Sano, Yuji

2003-01-01

Radiometric ages of detrital zircons in psammitic schists from the Nagasaki, Kurume, Konoha and Kiyama areas, northern Kyushu, were obtained from 238 U/ 206 Pb ratio and isotopic compositions of Pb using a Sensitive High Resolution Ion Microprobe (SHRIMP II). Zircons from the Nagasaki, Kurume and Konoha areas show bimodal age distribution with peaks at ca. 1900 Ma and 250 Ma. It is suggested from this study that the older zircons were derived from Proterozoic landmass and the Korean Peninsula. Zircons from the Kiyama metamorphic rock show a different pattern with ages concentrated at 380-590 Ma. Such zircons are rare in rock samples from the Nagasaki, Kurume and Konoha areas, indicating that Kiyama rocks and a different origin than those from the other three areas. The youngest zircons from the Kiyama, Nagasaki, Kurume and Konoha areas show ages of 382±23 Ma, 238±13 Ma, 249±13 Ma, and 175±4 Ma, respectively, These data mark the upper age limit of their deposition. Since a continuous igneous activity occurred during the period from 300 to 170 Ma in Far East Asia, and the metamorphic age has been close to the zircon age of each area, these youngest ages for the Nagasaki, Kurume and Konoha areas are considered nearly contemporary to the depositional ages. An evaluation of the nature of metamorphism and available ages suggest the possibility that the Nagasaki metamorphic rocks as well as the schist from the Kurume area belong to the Suo zone of the Sangun belt, whereas the metamorphic rocks in the Konoha area may belong to the Ryoke belt or Suo zone of the Sangun belt. (author)

Academic aspects of lunar water resources and their relevance to lunar protolife.

Science.gov (United States)

Green, Jack

2011-01-01

Water ice has been discovered on the moon by radar backscatter at the North Pole and by spectrometry at the South Pole in the Cabeus crater with an extrapolated volume for both poles of conservatively 10(9) metric tons. Various exogenic and endogenic sources of this water have been proposed. This paper focuses on endogenic water sources by fumaroles and hot springs in shadowed polar craters. A survey of theoretical and morphological details supports a volcanic model. Release of water and other constituents by defluidization over geological time was intensified in the Hadean Eon (c.a. 4600 to 4000 My). Intensification factors include higher heat flow by now-extinct radionuclides, tidal flexing and higher core temperatures. Lesser gravity would promote deeper bubble nucleation in lunar magmas, slower rise rates of gases and enhanced subsidence of lunar caldera floors. Hadean volcanism would likely have been more intense and regional in nature as opposed to suture-controlled location of calderas in Phanerozoic Benioff-style subduction environments. Seventy-seven morphological, remote sensing and return sample features were categorized into five categories ranging from a volcano-tectonic origin only to impact origin only. Scores for the most logical scenario were 69 to eight in favor of lunar volcanism. Ingredients in the Cabeus plume analysis showed many volcanic fluids and their derivatives plus a large amount of mercury. Mercury-rich fumaroles are well documented on Earth and are virtually absent in cometary gases and solids. There are no mercury anomalies in terrestrial impact craters. Volcanic fluids and their derivatives in lunar shadow can theoretically evolve into protolife. Energy for this evolution can be provided by vent flow charging intensified in the lunar Hadean and by charge separation on freezing fumarolic fluids in shadow. Fischer-Tropsch reactions on hydrothermal clays can yield lipids, polycyclic aromatic hydrocarbons and amino acids. Soluble

Zircon and ilmenite from the beach placers of southern coast of Tamil Nadu, east coast of India

International Nuclear Information System (INIS)

Angusamy, N.; Rajamanickam, G.V.; Loveson, V.J.

2004-01-01

Zircons were studied from the two different zones of enrichment of placer deposits namely, Kanyakumari-Kuttankuli (KK) and Kallar-Vaippar (VP) along the southern coast of Tamil Nadu. The average heavy mineral contents were 67 wt % for KK and 64 wt % in VP region. The heavy mineral assemblage of the two zones were akin to each other. However, monazite was present in the KK region. In KK, zircons were rounded (44.5 - 63.2 %), overgrown (4.1-16 %), and euhedral (9-4.9 %) while in VP, they are largely broken (47.8-59.6 %), rounded (22.2-38.9 %), and euhedral (7.3-8.1 %). Mean length and breadth of zircons of KK and VP ranged from 0.22-0.26 mm and 0.07-0.13 mm and, 0.06 - 0.16 mm and 0.07-0.11 mm, respectively. Zircons of VP are more fine-grained and well-rounded than KK. The northerly currents, in the Gulf of Mannar, must have transported and deposited the heavy minerals due to the inflection of coastline, and downwarped basinal structure. REE pattern of zircons exhibit Eu and Ce anomalies which could be explained only in terms of crystallochemical factors and the bulk compositional differences of the melt. In the study area, abundance of rounded zircons, length/breadth (L/B) ratios, reduced major axis (RMA) angles, indicated that the source rock for zircons must have been primarily of charnockites. The distribution, composition and REE content of zircons compare well with that of other countries where it is currently under exploitation. (author)

Interpretation of zircon coronae textures from metapelitic granulites of the Ivrea–Verbano Zone, northern Italy: two-stage decomposition of Fe–Ti oxides

Directory of Open Access Journals (Sweden)

E. Kovaleva

2017-07-01

Full Text Available In this study, we report the occurrence of zircon coronae textures in metapelitic granulites of the Ivrea–Verbano Zone. Unusual zircon textures are spatially associated with Fe–Ti oxides and occur as (1 vermicular-shaped aggregates 50–200 µm long and 5–20 µm thick and as (2 zircon coronae and fine-grained chains, hundreds of micrometers long and ≤ 1 µm thick, spatially associated with the larger zircon grains. Formation of such textures is a result of zircon precipitation during cooling after peak metamorphic conditions, which involved: (1 decomposition of Zr-rich ilmenite to Zr-bearing rutile, and formation of the vermicular-shaped zircon during retrograde metamorphism and hydration; and (2 recrystallization of Zr-bearing rutile to Zr-depleted rutile intergrown with quartz, and precipitation of the submicron-thick zircon coronae during further exhumation and cooling. We also observed hat-shaped grains that are composed of preexisting zircon overgrown by zircon coronae during stage (2. Formation of vermicular zircon (1 preceded ductile and brittle deformation of the host rock, as vermicular zircon is found both plastically and cataclastically deformed. Formation of thin zircon coronae (2 was coeval with, or immediately after, brittle deformation as coronae are found to fill fractures in the host rock. The latter is evidence of local, fluid-aided mobility of Zr. This study demonstrates that metamorphic zircon can nucleate and grow as a result of hydration reactions and mineral breakdown during cooling after granulite-facies metamorphism. Zircon coronae textures indicate metamorphic reactions in the host rock and establish the direction of the reaction front.

Lunar domes properties and formation processes

CERN Document Server

Lena, Raffaello; Phillips, Jim; Chiocchetta, Maria Teresa

2013-01-01

Lunar domes are structures of volcanic origin which are usually difficult to observe due to their low heights. The Lunar Domes Handbook is a reference work on these elusive features. It provides a collection of images for a large number of lunar domes, including telescopic images acquired with advanced but still moderately intricate amateur equipment as well as recent orbital spacecraft images. Different methods for determining the morphometric properties of lunar domes (diameter, height, flank slope, edifice volume) from image data or orbital topographic data are discussed. Additionally, multispectral and hyperspectral image data are examined, providing insights into the composition of the dome material. Several classification schemes for lunar domes are described, including an approach based on the determined morphometric quantities and spectral analyses. Furthermore, the book provides a description of geophysical models of lunar domes, which yield information about the properties of the lava from which the...

Fostering Outreach, Education and Exploration of the Moon Using the Lunar Mapping & Modeling Portal

Science.gov (United States)

Dodge, K.; Law, E.; Malhotra, S.; Chang, G.; Kim, R. M.; Bui, B.; Sadaqathullah, S.; Day, B. H.

2014-12-01

The Lunar Mapping and Modeling Portal (LMMP)[1], is a web-based Portal and a suite of interactive visualization and analysis tools for users to access mapped lunar data products (including image mosaics, digital elevation models, etc.) from past and current lunar missions (e.g., Lunar Reconnaissance Orbiter, Apollo, etc.). Originally designed as a mission planning tool for the Constellation Program, LMMP has grown into a generalized suite of tools facilitating a wide range of activities in support of lunar exploration including public outreach, education, lunar mission planning and scientific research. LMMP fosters outreach, education, and exploration of the Moon by educators, students, amateur astronomers, and the general public. These efforts are enhanced by Moon Tours, LMMP's mobile application, which makes LMMP's information accessible to people of all ages, putting opportunities for real lunar exploration in the palms of their hands. Our talk will include an overview of LMMP and a demonstration of its technologies (web portals, mobile apps), to show how it serves NASA data as commodities for use by advanced visualization facilities (e.g., planetariums) and how it contributes to improving teaching and learning, increasing scientific literacy of the general public, and enriching STEM efforts. References:[1] http://www.lmmp.nasa.gov

Drilling Automation Tests At A Lunar/Mars Analog Site

Science.gov (United States)

Glass, B.; Cannon, H.; Hanagud, S.; Lee, P.; Paulsen, G.

2006-01-01

Future in-situ lunar/martian resource utilization and characterization, as well as the scientific search for life on Mars, will require access to the subsurface and hence drilling. Drilling on Earth is hard - an art form more than an engineering discipline. The limited mass, energy and manpower in planetary drilling situations makes application of terrestrial drilling techniques problematic. The Drilling Automation for Mars Exploration (DAME) project is developing drilling automation and robotics for projected use in missions to the Moon and Mars in the 2011-15 period. This has been tested recently, drilling in permafrost at a lunar/martian analog site (Haughton Crater, Devon Island, Canada).

Searching for Lunar Horizon Glow With the Lunar Orbiter Laser Altimeter (LOLA)

Science.gov (United States)

Barker, M. K.; Mazarico, E. M.; McClanahan, T. P.; Sun, X.; Smith, D. E.; Neumann, G. A.; Zuber, M. T.; Head, J. W., III

2017-12-01

The dust environment of the Moon is sensitive to the interplanetary meteoroid population and dust transport processes near the lunar surface, and this affects many aspects of lunar surface science and planetary exploration. The interplanetary meteoroid population poses a significant risk to spacecraft, yet it remains one of the more uncertain constituents of the space environment. Observed and hypothesized lunar dust transport mechanisms have included impact-generated dust plumes, electrostatic levitation, and dynamic lofting. Many details of the impactor flux and impact ejection process are poorly understood, a fact highlighted by recent discrepant estimates of the regolith mixing rate. Apollo-era observations of lunar horizon glow (LHG) were interpreted as sunlight forward-scattered by exospheric dust grains levitating in the top meter above the surface or lofted to tens of kilometers in altitude. However, recent studies have placed limits on the dust density orders of magnitude less than what was originally inferred, raising new questions on the time variability of the dust environment. Motivated by the need to better understand dust transport processes and the meteoroid population, the Lunar Orbiter Laser Altimeter (LOLA) aboard the Lunar Reconnaissance Orbiter (LRO) is conducting a campaign to search for LHG with the LOLA Laser Ranging (LR) system. Advantages of this LOLA LHG search include: (1) the LOLA-LR telescope can observe arbitrarily close to the Sun at any time during the year without damaging itself or the other instruments, (2) a long temporal baseline with observations both during and outside of meteor streams, which will improve the chances of detecting LHG, and (3) a focus on altitudes methodology, and preliminary results.

Determination of Uranium, Thorium and Radium 226 in Zircon containig sands by alpha spectrometry

International Nuclear Information System (INIS)

Spezzano, P.

1985-01-01

The industrial utilization of Zircon sands for the production of refractories presents radiological problems owing to the risk of inhalation of Uranium, Thorium and their decay products, present in high concentrations in such materials. A method of analysis was realized for the determination of Uranium, Thorium and Radium-226 in Zircon sands, including the total dissolution of the sample, radiochemical separation and final measurement by alpha spectrometry with surface barrier detector. The concentrations of the main alpha-emitting radionuclides presents in two samples of Zircon sands have been determined and the possibility of disequilibrium along the decay series has been pointed out

In situ detrital zircon (U-Th)/He thermochronology

Science.gov (United States)

Tripathy, A.; Monteleone, B. D.; van Soest, M. C.; Hodges, K.; Hourigan, J. K.

2010-12-01

Detrital studies of both sand and rock are relevant to many problems, ranging from the climate and tectonics feedback debate to the long-term record of orogenic evolution. When applying the conventional (U-Th)/He technique to such studies, two important issues arise. Often, only euhedral grains are permissible for analysis in order to make simple geometric corrections for α-recoil. In detrital samples, this is problematic because euhedral grains can be scarce due to mechanical abrasion during transport, and potentially introduce bias in favour of more proximally sourced grains. Second, inherent to detrital studies is the need to date many grains (>100) per sample to ensure a representative sampling of the sediment source region, thus making robust conventional detrital studies both expensive and time-consuming. UV laser microprobes can improve this by permitting careful targeting of the grain interior away from the α-ejection zone, rendering the α-recoil correction unnecessary, thus eliminating bias toward euhedral grains. In the Noble Gas, Geochemistry, and Geochronology Laboratory at ASU, apatite and zircon have been successfully dated using in situ methods. For this study, the conventional and in situ techniques are compared by dating zircons from a modern river sand that drains a small catchment in the Mesozoic-Cenozoic Ladakh Batholith in NW India. This sample has a simple provenance, which allows us to demonstrate the robustness of the in situ method. Moreover, different microbeam techniques will be explored to establish the most efficient approach to obtain accurate and precise U-Th concentrations using synrock, which is our powdered, homogenized, and reconstituted zircon-rock standard. Without this, such in situ U-Th data would be difficult to obtain. 117 zircons were dated using the conventional (U-Th)/He method, revealing dates ranging from 9.70±0.35 to 106.6±3.5 Ma (2σ) with the major mode at 26 Ma. For comparison, 44 grains were dated using the in

Conceptual Design of Korea Aerospace Research Institute Lunar Explorer Dynamic Simulator

Directory of Open Access Journals (Sweden)

Dong-Young Rew

2010-12-01

Full Text Available In lunar explorer development program, computer simulator is necessary to provide virtual environments that vehicle confronts in lunar transfer, orbit, and landing missions, and to analyze dynamic behavior of the spacecraft under these environments. Objective of simulation differs depending on its application in spacecraft development cycle. Scope of use cases considered in this paper includes simulation of software based, processor and/or hardware in the loop, and support of ground-based flight test of developed vehicle. These use cases represent early phase in development cycle but reusability of modeling results in the next design phase is considered in defining requirements. A simulator architecture in which simulator platform is located in the middle and modules for modeling, analyzing, and three dimensional visualizing are connected to that platform is suggested. Baseline concepts and requirements for simulator development are described. Result of trade study for selecting simulation platform and approaches of defining other simulator components are summarized. Finally, characters of lunar elevation map data which is necessary for lunar terrain generation is described.

New SHRIMP U-Pb zircon ages of the metapelitic granulites from NW of Madurai, Southern India

International Nuclear Information System (INIS)

Prakash, D.

2010-01-01

Zircon cathodoluminescent imaging and SHRIMP U-Pb dating were carried out for metapelitic rocks (sapphirine-hearing granulites and garnet-cordierite gneisses) from the NW of Madurai, Southern India. The cathodoluminescence images reveal the complex, inhomogeneous internal structure having irregular-shaped core and overgrowths. Zircon grains have obliterated oscillatory zoning. SHRIMP U-Pb chronological results yield ages of 550 ± 15 Ma and 530 ± 50 Ma as a time of metamorphic overprint, and the age of 2509 ± 12 Ma and 2509 ± 30 Ma corresponding to a timing of protolith formation for sapphirine-bearing granulites and garnet-cordierite gneisses respectively. Zircon ages reflect that continental crust in the NW of Madurai region resulted from the recycling of Archaean protolith of an igneous origin similar to the preserved crust in the southern part of Dharwar craton. The present SHRIMP U-Pb zircon ages are in close agreement with earlier published Nd isotopic data which suggest an extended precrustal history of their protoliths. The abraded zircon grains indicate multiple recycling and repeated metamorphism that has ultimately resulted in present day continental crust exposed in Madurai region. These SHRIMP U-Pb zircon ages from metapelitic UHT granulites are also significant to understanding the architecture of the SGT during the amalgamation of Gondwana in Neoproterozoic time. (author)

Lunar surface engineering properties experiment definition

Science.gov (United States)

Mitchell, J. K.; Goodman, R. E.; Hurlbut, F. C.; Houston, W. N.; Willis, D. R.; Witherspoon, P. A.; Hovland, H. J.

1971-01-01

Research on the mechanics of lunar soils and on developing probes to determine the properties of lunar surface materials is summarized. The areas of investigation include the following: soil simulation, soil property determination using an impact penetrometer, soil stabilization using urethane foam or phenolic resin, effects of rolling boulders down lunar slopes, design of borehole jack and its use in determining failure mechanisms and properties of rocks, and development of a permeability probe for measuring fluid flow through porous lunar surface materials.

Pb, U, Ti, Hf and Zr distributions in zircons determined by proton microprobe and fission track techniques

International Nuclear Information System (INIS)

Clark, G.J.; Gulson, B.L.; Cookson, J.A.

1979-01-01

A proton microprobe has been used to determine Pb, Tl, Hf and Zr distributions across four single zircon crystals separated from a 'rapakivi' granite. The Pb and Zr data are quantitative: Pb and Tl concentrations were below the measurable limits for determinations in situ by most other techniques. The distribution of U in the same crystals was determined by the fission track technique. Limits on precision of U allow only a qualitative correlation of U and Pb, whereas the Tl and Pb correlation is more exactly determined. Zircons with distinct cores and overgrowths exhibited uniform Zr and Hf concentrations across the crystals, whereas the high U rims and 'inclusions' (domains) also had high Tl and Pb contents. Since almost all the Pb in these zircons is derived by radioactive decay of U, the Tl substitution has paralleled that of U. The results indicate that the high U domains are 'hot spots' rather than a separate mineral phase. The strong positive correlation of U and Pb indicates that there is little U daughter product migration relative to U, within the crystal. However, for the zircon population investigated here, the data are equivocal on the question of whether U addition to zircon crystals is associated with new zircon growth or not. In either case, the heterogeneous U and Pb distributions complicate any interpretations of U-Pb isotopic analysis for such zircon populations. (author)

Multi-mode Li diffusion in natural zircons: Evidence for diffusion in the presence of step-function concentration boundaries

Science.gov (United States)

Tang, Ming; Rudnick, Roberta L.; McDonough, William F.; Bose, Maitrayee; Goreva, Yulia

2017-09-01

Micron- to submicron-scale observations of Li distribution and Li isotope composition profiles can be used to infer the mechanisms of Li diffusion in natural zircon. Extreme fractionation (20-30‰) within each single crystal studied here confirms that Li diffusion commonly occurs in zircon. Sharp Li concentration gradients frequently seen in zircons suggest that the effective diffusivity of Li is significantly slower than experimentally determined (Cherniak and Watson, 2010; Trail et al., 2016), otherwise the crystallization/metamorphic heating of these zircons would have to be unrealistically fast (years to tens of years). Charge coupling with REE and Y has been suggested as a mechanism that may considerably reduce Li diffusivity in zircon (Ushikubo et al., 2008; Bouvier et al., 2012). We show that Li diffused in the direction of decreasing Li/Y ratio and increasing Li concentration (uphill diffusion) in one of the zircons, demonstrating charge coupling with REE and Y. Quantitative modeling reveals that Li may diffuse in at least two modes in natural zircons: one being slow and possibly coupled with REE+Y, and the other one being fast and not coupled with REE+Y. The partitioning of Li between these two modes during its diffusion may depend on the pre-diffusion substitution mechanism of REE and Y in the zircon lattice. Based on our results, sharp Li concentration gradients are not indicative of limited diffusion, and can be preserved at temperatures >700 °C on geologic timescales. Finally, large δ7 Li variations observed in the Hadean Jack Hills zircons may record kinetic fractionation, rather than a record of ancient intense weathering in the granite source materials.

Analyze of viability of ZrSiO_4-Fe_2O_3 pigments synthesis, from decomposition of the zircon

International Nuclear Information System (INIS)

Prim, S.R.; Folgueiras, M.V.; Winter, D.M.

2011-01-01

Zircon pigments are commonly used in ceramic industry due to their high chemical and thermal stability. In the present work, the viability of synthesis of a zircon ceramic pigment from intermediate products obtained from decomposition zircon sand with NaOH and/or KOH at 750 and 850 °C was studied. The intermediate products were used as raw materials to produce pigments. Iron oxide from rolling process of sheet metal was used as chromophore. The crystalline phases formed were characterized by X-ray diffraction. The results have shown that it was possible to obtain the partial decomposition of zircon which enables the development of the synthesis of zircon pigment. (author)

Electrophoretic growth of lead zirconate titanate nanorods

Energy Technology Data Exchange (ETDEWEB)

Limmer, S.J.; Seraji, S.; Forbess, M.J.; Wu Yun; Chou, T.P.; Nguyen, C.; Cao Guozhong [Washington Univ., Seattle, WA (United States). Dept. of Materials Science and Engineering

2001-08-16

Nanorods of lead zirconate titanate (PZT)-a ferro- and piezoelectric material-up to 10 {mu}m in length and 70 to 150 nm in diameter are produced by sol-gel electrophoresis of PZT in a track-etched polycarbonate membrane, which is used as a template. (orig.)

Endogenous Lunar Volatiles

Science.gov (United States)

McCubbin, F. M.; Liu, Y.; Barnes, J. J.; Boyce, J. W.; Day, J. M. D.; Elardo, S. M.; Hui, H.; Magna, T.; Ni, P.; Tartese, R.;

Hydrogen Distribution in the Lunar Polar Regions

Science.gov (United States)

Sanin, A. B.; Mitrofanov, I. G.; Litvak, M. L.; Bakhtin, B. N.; Bodnarik, J. G.; Boynton, W. V.; Chin, G.; Evans, L. G.; Harshmann, K.; Fedosov, F.;

Structural analysis of radiation damage in zircon and thorite: An X-ray absorption spectroscopic study

International Nuclear Information System (INIS)

Farges, F.; Calas, G.

1991-01-01

Metamictization effects have been investigated in zircon, thorite, uranothorite, and thorogummite using X-ray absorption spectroscopy at Zr-K, Th-L III edges. Extended X-ray absorption fine structure (EXAFS) spectra of metamict samples are characterized by a major contribution due to the O nearest neighbors with some contributions from next-nearest neighbors (Si and Zr in zircon, Si in thorite). In zircon, Zr-O distances decrease by ∼0.1 angstrom while the coordination number of Zr decreases from 8 to 7. In contrast, the eightfold coordination of Th in crystalline thorite is preserved in metamict thorite, Si second neighbors around Zr or Th are generally observed in metamict samples with distances close to those measured in crystalline phases. No other contribution to EXAFS is observed in thorite, but Zr-Zr distances are observed in zircon. They decrease by ca. 0.3 Angstrom as a function of zircon metamictization. Metamictization processes are characterized by a loss of medium range order. There is no evidence for decomposition into crystalline oxides. The structural interpretation of EXAFS data must take into account the creation of O vacancies arising from a displacement or tilting of the SiO 4 tetrahedra during metamictization of zircon-like structures. If the cation can take a lower coordination number (as in the case of Zr), a coordination change allows the local structure to be partly maintained during metamictization. If not, as for Th, the local structure is rapidly destroyed

Erosive Wear Characterization of Materials for Lunar Construction

Science.gov (United States)

Mpagazehe, Jeremiah N.; Street, Kenneth W., Jr.; Delgado, Irebert R.; Higgs, C. Fred, III

2012-01-01

NASA s Apollo missions revealed that exhaust from the retrorockets of landing spacecraft may act to significantly accelerate lunar dust on the surface of the Moon. A recent study by Immer et al. (C. Immer, P.T. Metzger, P.E. Hintze, A. Nick, and R. Horan, Apollo 12 Lunar Module exhaust plume impingement on Lunar Surveyor III, Icarus, Vol. 211, pp. 1089-1102, 2011) investigated coupons returned to Earth from the Surveyor III lunar probe which were subjected to lunar dust impingement by the Apollo 12 Lunar Module landing. Their study revealed that even with indirect impingement, the spacecraft sustained erosive damage from the fast-moving lunar dust particles. In this work, results are presented from a series of erosive wear experiments performed on 6061 Aluminum using the JSC-1AF lunar dust simulant. Optical profilometry was used to investigate the surface after the erosion process. It was found that even short durations of lunar dust simulant impacting at low velocities produced substantial changes in the surface.

Respiratory Toxicity of Lunar Highland Dust

Science.gov (United States)

James, John T.; Lam, Chiu-wing; Wallace, William T.

2009-01-01

Lunar dust exposures occurred during the Apollo missions while the crew was on the lunar surface and especially when microgravity conditions were attained during rendezvous in lunar orbit. Crews reported that the dust was irritating to the eyes and in some cases respiratory symptoms were elicited. NASA s vision for lunar exploration includes stays of 6 months on the lunar surface hence the health effects of periodic exposure to lunar dust need to be assessed. NASA has performed this assessment with a series of in vitro and in vivo tests on authentic lunar dust. Our approach is to "calibrate" the intrinsic toxicity of lunar dust by comparison to a nontoxic dust (TiO2) and a highly toxic dust (quartz) using intratrachael instillation of the dusts in mice. A battery of indices of toxicity is assessed at various time points after the instillations. Cultures of selected cells are exposed to test dusts to assess the adverse effects on the cells. Finally, chemical systems are used to assess the nature of the reactivity of various dusts and to determine the persistence of reactivity under various environmental conditions that are relevant to a space habitat. Similar systems are used to assess the dissolution of the dust. From these studies we will be able to set a defensible inhalation exposure standard for aged dust and predict whether we need a separate standard for reactive dust. Presently-available data suggest that aged lunar highland dust is slightly toxic, that it can adversely affect cultured cells, and that the surface reactivity induced by grinding the dust persists for a few hours after activation.

Ferroelectric devices using lead zirconate titanate (PZT) nanoparticles.

Science.gov (United States)

Paik, Young Hun; Kojori, Hossein Shokri; Kim, Sung Jin

2016-02-19

We successfully demonstrate the synthesis of lead zirconate titanate nanoparticles (PZT NPs) and a ferroelectric device using the synthesized PZT NPs. The crystalline structure and the size of the nanocrystals are studied using x-ray diffraction and transmission electron microscopy, respectively. We observe PZT NPs and this result matches dynamic light scattering measurements. A solution-based low-temperature process is used to fabricate PZT NP-based devices on an indium tin oxide substrate. The fabricated ferroelectric devices are characterized using various optical and electrical measurements and we verify ferroelectric properties including ferroelectric hysteresis and the ferroelectric photovoltaic effect. Our approach enables low-temperature solution-based processes that could be used for various applications. To the best of our knowledge, this low-temperature solution processed ferroelectric device using PZT NPs is the first successful demonstration of its kind.

Major zircon megacryst suites of the Indo-Pacific lithospheric margin (ZIP) and their petrogenetic and regional implications

Science.gov (United States)

Sutherland, Lin; Graham, Ian; Yaxley, Gregory; Armstrong, Richard; Giuliani, Gaston; Hoskin, Paul; Nechaev, Victor; Woodhead, Jon

2016-04-01

Zircon megacrysts (± gem corundum) appear in basalt fields of Indo-Pacific origin over a 12,000 km zone (ZIP) along West Pacific continental margins. Age-dating, trace element, oxygen and hafnium isotope studies on representative zircons (East Australia-Asia) indicate diverse magmatic sources. The U-Pb (249 to 1 Ma) and zircon fission track (ZFT) ages (65 to 1 Ma) suggest thermal annealing during later basalt transport, with < 1 to 203 Ma gaps between the U-Pb and ZFT ages. Magmatic growth zonation and Zr/Hf ratios (0.01-0.02) suggest alkaline magmatic sources, while Ti—in—zircon thermometry suggests that most zircons crystallized within ranges between 550 and 830 °C. Chondrite-normalised multi-element plots show variable enrichment patterns, mostly without marked Eu depletion, indicating little plagioclase fractionation in source melts. Key elements and ratios matched against zircons from magmatic rocks suggest a range of ultramafic to felsic source melts. Zircon O-isotope ratios (δ18O in the range 4 to 11‰) and initial Hf isotope ratios (ɛHf in the range +2 to +14) encompass ranges for both mantle and crustal melts. Calculated Depleted Mantle (TDM 0.03-0.56 Ga) and Crustal Residence (0.20-1.02 Ga) model ages suggest several mantle events, continental break-ups (Rodinia and Gondwana) and convergent margin collisions left imprints in the zircon source melts. East Australian ZIP sites reflect prolonged intraplate magmatism (~85 Ma), often during times of fast-migrating lithosphere. In contrast, East Asian-Russian ZIP sites reflect later basaltic magmatism (<40 Ma), often linked to episodes of back-arc rifting and spreading, slow-migrating lithosphere and slab subduction.

[Possibility of exacerbation of allergy by lunar regolith].

Science.gov (United States)

Horie, Masanori; Kambara, Tatsunori; Kuroda, Etsushi; Miki, Takeo; Honma, Yoshiyuki; Aoki, Shigeru; Morimoto, Yasuo

2012-09-01

Japan, U.S.A. and other foreign space agencies have plans for the construction of a lunar base and long-term stay of astronauts on the moon. The surface of the moon is covered by a thick layer of soil that includes fine particles called "lunar regolith", which is formed by meteorite impact and space weathering. Risk assessment of particulate matter on the moon is important for astronauts working in microgravity on the moon. However, there are few investigations about the biological influences of lunar regolith. Especially, there is no investigation about allergic activity to lunar regolith. The main chemical components of lunar regolith are SiO2, Al2O3, CaO, FeO, etc. Of particular interest, approximately 50% of lunar regolith consists of SiO2. There is a report that the astronauts felt hay fever-like symptoms from the inhalation of the lunar regolith. Yellow sand, whose chemical components are similar to lunar regolith, enhances allergenic reactions, suggesting the possibility that lunar regolith has an adjuvant-like activity. Although intraperitoneal administration of lunar regolith with ovalbumin to mouse did not show enhancement of allergenic reactions, further evaluation of lunar regolith's potential to exacerbate the effects of allergies is essential for development of the moon.

Lunar phases and crisis center telephone calls.

Science.gov (United States)

Wilson, J E; Tobacyk, J J

1990-02-01

The lunar hypothesis, that is, the notion that lunar phases can directly affect human behavior, was tested by time-series analysis of 4,575 crisis center telephone calls (all calls recorded for a 6-month interval). As expected, the lunar hypothesis was not supported. The 28-day lunar cycle accounted for less than 1% of the variance of the frequency of crisis center calls. Also, as hypothesized from an attribution theory framework, crisis center workers reported significantly greater belief in lunar effects than a non-crisis-center-worker comparison group.

Rapid cooling rates at an active mid-ocean ridge from zircon thermochronology

Science.gov (United States)

Schmitt, Axel K.; Perfit, Michael R.; Rubin, Kenneth H.; Stockli, Daniel F.; Smith, Matthew C.; Cotsonika, Laurie A.; Zellmer, Georg F.; Ridley, W. Ian

2011-01-01

Oceanic spreading ridges are Earth's most productive crust generating environment, but mechanisms and rates of crustal accretion and heat loss are debated. Existing observations on cooling rates are ambiguous regarding the prevalence of conductive vs. convective cooling of lower oceanic crust. Here, we report the discovery and dating of zircon in mid-ocean ridge dacite lavas that constrain magmatic differentiation and cooling rates at an active spreading center. Dacitic lavas erupted on the southern Cleft segment of the Juan de Fuca ridge, an intermediate-rate spreading center, near the intersection with the Blanco transform fault. Their U–Th zircon crystallization ages (29.3-4.6+4.8 ka; 1δ standard error s.e.) overlap with the (U–Th)/He zircon eruption age (32.7 ± 1.6 ka) within uncertainty. Based on similar 238U-230Th disequilibria between southern Cleft dacite glass separates and young mid-ocean ridge basalt (MORB) erupted nearby, differentiation must have occurred rapidly, within ~ 10–20 ka at most. Ti-in-zircon thermometry indicates crystallization at 850–900 °C and pressures > 70–150 MPa are calculated from H2O solubility models. These time-temperature constraints translate into a magma cooling rate of ~ 2 × 10-2 °C/a. This rate is at least one order-of-magnitude faster than those calculated for zircon-bearing plutonic rocks from slow spreading ridges. Such short intervals for differentiation and cooling can only be resolved through uranium-series (238U–230Th) decay in young lavas, and are best explained by dissipating heat convectively at high crustal permeability.

Lunar magma transport phenomena

Science.gov (United States)

Spera, Frank J.

1992-01-01

An outline of magma transport theory relevant to the evolution of a possible Lunar Magma Ocean and the origin and transport history of the later phase of mare basaltic volcanism is presented. A simple model is proposed to evaluate the extent of fractionation as magma traverses the cold lunar lithosphere. If Apollo green glasses are primitive and have not undergone significant fractionation en route to the surface, then mean ascent rates of 10 m/s and cracks of widths greater than 40 m are indicated. Lunar tephra and vesiculated basalts suggest that a volatile component plays a role in eruption dynamics. The predominant vapor species appear to be CO CO2, and COS. Near the lunar surface, the vapor fraction expands enormously and vapor internal energy is converted to mixture kinetic energy with the concomitant high-speed ejection of vapor and pyroclasts to form lunary fire fountain deposits such as the Apollo 17 orange and black glasses and Apollo 15 green glass.

Modelling of Lunar Dust and Electrical Field for Future Lunar Surface Measurements

Science.gov (United States)

Lin, Yunlong

Modelling of the lunar dust and electrical field is important to future human and robotic activities on the surface of the moon. Apollo astronauts had witnessed the maintaining of micron- and millimeter sized moon dust up to meters level while walked on the surface of the moon. The characterizations of the moon dust would enhance not only the scientific understanding of the history of the moon but also the future technology development for the surface operations on the moon. It has been proposed that the maintaining and/or settlement of the small-sized dry dust are related to the size and weight of the dust particles, the level of the surface electrical fields on the moon, and the impaction and interaction between lunar regolith and the solar particles. The moon dust distributions and settlements obviously affected the safety of long term operations of future lunar facilities. For the modelling of the lunar dust and the electrical field, we analyzed the imaging of the legs of the moon lander, the cover and the footwear of the space suits, and the envelope of the lunar mobiles, and estimated the size and charges associated with the small moon dust particles, the gravity and charging effects to them along with the lunar surface environment. We also did numerical simulation of the surface electrical fields due to the impaction of the solar winds in several conditions. The results showed that the maintaining of meters height of the micron size of moon dust is well related to the electrical field and the solar angle variations, as expected. These results could be verified and validated through future on site and/or remote sensing measurements and observations of the moon dust and the surface electrical field.

Detrital zircon ages from southern Norway - implications for the Proterozoic evolution of the southwestern Baltic Shield

Science.gov (United States)

Knudsen, T.-L.; Andersen, T.; Whitehouse, M. J.; Vestin, J.

An ion-microprobe (SIMS) U-Pb zircon dating study on four samples of Precambrian metasediments from the high-grade Bamble Sector, southern Norway, gives the first information on the timing of discrete crust-forming events in the SW part of the Baltic Shield. Recent Nd and Pb studies have indicated that the sources of the clastic metasediments in this area have crustal histories extending back to 1.7 to 2.1Ga, although there is no record of rocks older than 1.6Ga in southern Norway. The analysed metasediments are from a sequence of intercalated, centimetre to 10-metre wide units of quartzites, semi-metapelites, metapelites and mafic granulites. The zircons can be grouped in two morphological populations: (1) long prismatic; (2) rounded, often flattened. The BSE images reveal that both populations consist of oscillatory zoned, rounded and corroded cores (detrital grains of magmatic origin), surrounded by homogeneous rims (metamorphic overgrowths). The detrital zircons have 207Pb/206Pb ages between 1367 and 1939Ma, with frequency maxima in the range 1.85 to 1.70Ga and 1.60 to 1.50Ga. There is no correlation between crystal habit and age of the zircon. One resorbed, inner zircon core in a detrital grain is strongly discordant and gives a composite inner core-magmatic outer core 207Pb/206Pb age of 2383 Ma. Two discrete, unzoned zircons have 207Pb/206Pb ages of 1122 and 1133Ma, representing zircon growth during the Sveconorwegian high-grade metamorphism. Also the μm wide overgrowths, embayments in the detrital cores and apparent ``inner cores'' which represent secondary metamorphic zircon growth in deep embayments in detrital grains, are of Sveconorwegian age. The composite-detrital-metamorphic zircon analyses give generally discordant 206Pb/238U versus 207Pb/235U ratios and maximum 207Pb/206Pb ages of 1438Ma. These data demonstrate the existence of a protocrust of 1.7 to 2.0Ga in the southwestern part of the Baltic Shield, implying a break in the overall westward

Overturn of magma ocean ilmenite cumulate layer: Implications for lunar magmatic evolution and formation of a lunar core

Science.gov (United States)

Hess, P. C.; Parmentier, E. M.

1993-01-01

We explore a model for the chemical evolution of the lunar interior that explains the origin and evolution of lunar magmatism and possibly the existence of a lunar core. A magma ocean formed during accretion differentiates into the anorthositic crust and chemically stratified cumulate mantle. The cumulative mantle is gravitationally unstable with dense ilmenite cumulate layers overlying olivine-orthopyroxene cumulates with Fe/Mg that decreases with depth. The dense ilmenite layer sinks to the center of the moon forming the core. The remainder of the gravitationally unstable cumulate pile also overturns. Any remaining primitive lunar mantle rises to its level of neutral buoyancy in the cumulate pile. Perhaps melting of primitive lunar mantle due to this decompression results in early lunar Mg-rich magmatism. Because of its high concentration of incompatible heat producing elements, the ilmenite core heats the overlying orthopyroxene-bearing cumulates. As a conductively thickening thermal boundary layer becomes unstable, the resulting mantle plumes rise, decompress, and partially melt to generate the mare basalts. This model explains both the timing and chemical characteristics of lunar magmatism.

Understanding the Lunar System Architecture Design Space

Science.gov (United States)

Arney, Dale C.; Wilhite, Alan W.; Reeves, David M.

2013-01-01

Based on the flexible path strategy and the desire of the international community, the lunar surface remains a destination for future human exploration. This paper explores options within the lunar system architecture design space, identifying performance requirements placed on the propulsive system that performs Earth departure within that architecture based on existing and/or near-term capabilities. The lander crew module and ascent stage propellant mass fraction are primary drivers for feasibility in multiple lander configurations. As the aggregation location moves further out of the lunar gravity well, the lunar lander is required to perform larger burns, increasing the sensitivity to these two factors. Adding an orbit transfer stage to a two-stage lunar lander and using a large storable stage for braking with a one-stage lunar lander enable higher aggregation locations than Low Lunar Orbit. Finally, while using larger vehicles enables a larger feasible design space, there are still feasible scenarios that use three launches of smaller vehicles.

Lunar Dust Separation for Toxicology Studies

Science.gov (United States)

Cooper, Bonnie L.; McKay, D. S.; Riofrio, L. M.; Taylor, L. A.; Gonzalex, C. P.

2010-01-01

During the Apollo missions, crewmembers were briefly exposed to dust in the lunar module, brought in after extravehicular activity. When the lunar ascent module returned to micro-gravity, the dust that had settled on the floor now floated into the air, causing eye discomfort and occasional respiratory symptoms. Because our goal is to set an exposure standard for 6 months of episodic exposure to lunar dust for crew on the lunar surface, these brief exposures of a few days are not conclusive. Based on experience with industrial minerals such as sandblasting quartz, an exposure of several months may cause serious damage, while a short exposure may cause none. The detailed characteristics of sub-micrometer lunar dust are only poorly known, and this is the size range of particles that are of greatest concern. We have developed a method for extracting respirable dust (<2.5 micron) from Apollo lunar soils. This method meets stringent requirements that the soil must be kept dry, exposed only to pure nitrogen, and must conserve and recover the maximum amount of both respirable dust and coarser soil. In addition, we have developed a method for grinding coarser lunar soil to produce sufficient respirable soil for animal toxicity testing while preserving the freshly exposed grain surfaces in a pristine state.

Status and Future of Lunar Geoscience.

Science.gov (United States)

1986

A review of the status, progress, and future direction of lunar research is presented in this report from the lunar geoscience working group of the National Aeronautics and Space Administration. Information is synthesized and presented in four major sections. These include: (1) an introduction (stating the reasons for lunar study and identifying…

U-Pb ages of detrital zircon from Pegasus Group, Stewart Island

International Nuclear Information System (INIS)

Walker, N.; Tulloch, A.J.; Allibone, A.

1998-01-01

Stewart Island (New Zealand) is relatively unaffected by Cenozoic deformation related to the present-day plate boundary and has thus been a locale of investigations that focus on the relationship between Mesozoic continental margin magmatic rocks and the Western Province (WP) of NZ. Pegasus Group metasedimentary rocks represent the only candidate for WP equivalents on Stewart Island. We measured U-Pb and 207 Pb / 206 Pb ages of detrital zircons from the Pegasus Group in an effort to validate the correlation with the WP. On SI, Pegasus Group is exposed over a small area in the southern Tin Range where it forms amphibolite facies roof pendants and screens among plutons of mid Paleozoic to mid Cretaceous age. Mica schists predominate, with lesser amounts of psammite and metaquartzite and rare calcareous schist and amphibolite. Zircons were extracted from metaquarzite and 24 grains were chosen on the basis of morphology for geochronologic investigation. Sixteen single crystals were dated by U-Pb TIMS; 8 additional grains were studied by the total evaporation method described by Kober. Despite vigorous air abrasion prior to processing, the 16 grains measured by conventional U-Pb TIMS yielded slightly normally discordant ages that we interpret to reflect minor Pb-loss. The 8 grains studied by the total evaporation method yielded more than four analytically identical /sup 207 Pb / 206 Pb ages within each grain at progressively higher temperatures (1515-1580 degrees C) of evaporation. The results permit the following general conclusions: 1) the age range of 420-2700 Ma is grossly similar to that reported from the Greenland Group/Victoria Paragneiss (Ireland 1992) of the Buller Terrane, WP; 2) the zircon population is dominantly 530-680 Ma but a subsidiary population is 900-1100 Ma; 3) no zircons with ages that match the timing of the Ross Orogen (530-480 Ma) were identified; 4) two grains of 420 Ma and a 453 Ma are probably too young for the paleontogically

Nanophase Fe0 in lunar soils

Indian Academy of Sciences (India)

globules that occur in the rinds of many soil grains and in the ... tinitic glass is a quenched product of silicate melts, also produced by micrometeorite impacts on lunar soils ..... stand impact processes and their products. ... cules at night; the earth's atmosphere by con- .... deep lunar interior from an inversion of lunar free oscil-.

Extraction of Water from Lunar Permafrost

Science.gov (United States)

Ethridge, Edwin C.; Kaukler, William

2009-01-01

Remote sensing indicates the presence of hydrogen rich regions associated with the lunar poles. The logical hypothesis is that there is cryogenically trapped water ice located in craters at the lunar poles. Some of the craters have been in permanent darkness for a billion years. The presence of water at the poles as well as other scientific advantages of a polar base, have influenced NASA plans for the lunar outpost. The lunar outpost has water and oxygen requirements on the order of 1 ton per year scaling up to as much as 5 tons per year. Microwave heating of the frozen permafrost has unique advantages for water extraction. Proof of principle experiments have successfully demonstrated that microwaves will couple to the cryogenic soil in a vacuum and the sublimed water vapor can be successfully captured on a cold trap. Dielectric property measurements of lunar soil simulant have been measured. Microwave absorption and attenuation in lunar soil simulant has been correlated with measured dielectric properties. Future work will be discussed.

Lunar Industry & Research Base Concept

Science.gov (United States)

Lysenko, J.; Kaliapin, M.; Osinovyy, G.

2017-09-01

Currently, all main space industry players, such as Europe, USA, Russia, China, etc., are looking back again at the idea of Moon exploration building there a manned lunar base. Alongside with other world spacefaring nations, Yuzhnoye State Design Office with its long-time development experience, technological and intellectual potential, organized its own conceptual work on development of the Lunar Industry & Research Base. In the frames of conceptual project "Lunar Industrial & Research Base" were formed its appearance, preliminary configuration and infrastructure at different stages of operation, trajectory and flight scheme to the Moon, as well as terms of the project's realization, and main technical characteristics of the systems under development, such as space transportation system for crew and cargo delivery to lunar surface and return to Earth, standardized designs of lunar modules, lunar surface vehicles, etc. The "Lunar Industrial & Research Base" project's preliminary risk assessment has shown a high value of its overall risk due to the lack of reliable information about the Moon, technical risks, long-term development of its elements, very high financial costs and dependence on state support. This points to the fact that it is reasonable to create such a global project in cooperation with other countries. International cooperation will expand the capabilities of any nation, reduce risks and increase the success probability of automated or manned space missions. It is necessary to create and bring into operation practical mechanisms for long-term space exploration on a global scale. One of the ways to do this is to create a multinational agency which would include both state enterprises and private companies.

Microstructural evaluation of alumina-niobium and alumina- niobium-zircon ceramics for ballistic application

International Nuclear Information System (INIS)

Mota, Juliana Machado da; Lopes, Cristina Moniz Araujo; Melo, Francisco Lourenco Cristovao de

2009-01-01

This study aimed to evaluate the microstructural of Alumina- Niobium and Alumina- Niobium-Zircon ceramics. Samples with 3.5 x 4.5 x 34 mm dimensions were prepared by uniaxial pressure (50 MPa) followed by isostatic pressure (300 MPa). The samples were sintered at 1500 ° C for 1 hour. The ceramics obtained were characterized by scanning electron microscopy (SEM) and X-ray diffraction, to evaluate the phases and microstructures. In order to analyze the microstructure, by SEM the samples were prepared using two techniques: heat treatment (1350 ° C for 5 minutes) and thermochemical treatment (500 ° C for 8 minutes in a solution of NaOH and KOH) on polished and fractured surfaces. The results showed that despite differences between the two etchings, both were effective to analyze the microstructure. (author)

Solid-support substrates for plant growth at a lunar base

Science.gov (United States)

Ming, D. W.; Galindo, C.; Henninger, D. L.

1990-01-01

Zeoponics is only in its developmental stages at the Johnson Space Center and is defined as the cultivation of plants in zeolite substrates that contain several essential plant growth cations on their exchange sites, and have minor amounts of mineral phases and/or anion-exchange resins that supply essential plant growth anions. Zeolites are hydrated aluminosilicates of alkali and alkaline earth cations with the ability to exchange most of their constituent exchange cations as well as hydrate/dehydrate without change to their structural framework. Because zeolites have extremely high cation exchange capabilities, they are very attractive media for plant growth. It is possible to partially or fully saturate plant-essential cations on zeolites. Zeoponic systems will probably have their greatest applications at planetary bases (e.g., lunar bases). Lunar raw materials will have to be located that are suited for the synthesis of zeolites and other exchange resings. Lunar 'soil' simulants have been or are being prepared for zeolite/smectite synthesis and 'soil' dissolution studies.

On the connection of the ESR characteristics of zircons with the degree of their defectiveness

International Nuclear Information System (INIS)

Matyash, I.V.; Brik, A.E.; Derski, L.S.; Larikov, A.L.; Ponomarenko, A.N.

1989-01-01

The dynamic characteristics of the electron-hole centres (EHC) in zircons with various degree of defectiveness have been studied. Crystalline and amorphous regions are typical of different sets of EHC, having essentially different relaxation characteristics. Lack of cross-relaxation between these centres shows that they are localized in different parts of the crystal. The influence of autoirradiation and of corresponding defectiveness of the matrix upon the intensity of the EHC signals (V i ) has been studied. In the specimens of high crystallinity V i increases as the content of radioactive elements and defectiveness increases. In the essentially metamict specimens the situation reverses. Interpretation of this effect is given considering the dose dependence of the ESR signals and the ratio of the crystal and metamict volumes in the studied object. The transformations of the EHC set is traced along the amorphization of the zircon matrix due to the autoirradiation. ESR signals corresponding to different phases in zircon have been recorded. The correlation of the zircon grain size and the static magnetic susceptibility with V i have been studied. In the specimens of high crystallinity such correlation is absent and in metamict specimens the intensities V i decrease as the grain sizes decrease. The interpretation of this fact is proposed. It has been shown that the ESR studies reflect the processes of income and migration of the impurity elements in zircons and the ways of the zircon crystal matrix decay in a geological time scale. The factors controlling such a decay have been found. (author)

Nanogeochronology of discordant zircon measured by atom probe microscopy of Pb-enriched dislocation loops

Science.gov (United States)

Peterman, Emily M.; Reddy, Steven M.; Saxey, David W.; Snoeyenbos, David R.; Rickard, William D. A.; Fougerouse, Denis; Kylander-Clark, Andrew R. C.

2016-01-01

Isotopic discordance is a common feature in zircon that can lead to an erroneous age determination, and it is attributed to the mobilization and escape of radiogenic Pb during its post-crystallization geological evolution. The degree of isotopic discordance measured at analytical scales of ~10 μm often differs among adjacent analysis locations, indicating heterogeneous distributions of Pb at shorter length scales. We use atom probe microscopy to establish the nature of these sites and the mechanisms by which they form. We show that the nanoscale distribution of Pb in a ~2.1 billion year old discordant zircon that was metamorphosed c. 150 million years ago is defined by two distinct Pb reservoirs. Despite overall Pb loss during peak metamorphic conditions, the atom probe data indicate that a component of radiogenic Pb was trapped in 10-nm dislocation loops that formed during the annealing of radiation damage associated with the metamorphic event. A second Pb component, found outside the dislocation loops, represents homogeneous accumulation of radiogenic Pb in the zircon matrix after metamorphism. The 207Pb/206Pb ratios measured from eight dislocation loops are equivalent within uncertainty and yield an age consistent with the original crystallization age of the zircon, as determined by laser ablation spot analysis. Our results provide a specific mechanism for the trapping and retention of radiogenic Pb during metamorphism and confirm that isotopic discordance in this zircon is characterized by discrete nanoscale reservoirs of Pb that record different isotopic compositions and yield age data consistent with distinct geological events. These data may provide a framework for interpreting discordance in zircon as the heterogeneous distribution of discrete radiogenic Pb populations, each yielding geologically meaningful ages. PMID:27617295

Lunar phase-dependent expression of cryptochrome and a photoperiodic mechanism for lunar phase-recognition in a reef fish, goldlined spinefoot.

Science.gov (United States)

Fukushiro, Masato; Takeuchi, Takahiro; Takeuchi, Yuki; Hur, Sung-Pyo; Sugama, Nozomi; Takemura, Akihiro; Kubo, Yoko; Okano, Keiko; Okano, Toshiyuki

2011-01-01

Lunar cycle-associated physiology has been found in a wide variety of organisms. Recent study has revealed that mRNA levels of Cryptochrome (Cry), one of the circadian clock genes, were significantly higher on a full moon night than on a new moon night in coral, implying the involvement of a photoreception system in the lunar-synchronized spawning. To better establish the generalities surrounding such a mechanism and explore the underlying molecular mechanism, we focused on the relationship between lunar phase, Cry gene expression, and the spawning behavior in a lunar-synchronized spawner, the goldlined spinefoot (Siganus guttatus), and we identified two kinds of Cry genes in this animal. Their mRNA levels showed lunar cycle-dependent expression in the medial part of the brain (mesencephalon and diencephalon) peaking at the first quarter moon. Since this lunar phase coincided with the reproductive phase of the goldlined spinefoot, Cry gene expression was considered a state variable in the lunar phase recognition system. Based on the expression profiles of SgCrys together with the moonlight's pattern of timing and duration during its nightly lunar cycle, we have further speculated on a model of lunar phase recognition for reproductive control in the goldlined spinefoot, which integrates both moonlight and circadian signals in a manner similar to photoperiodic response.

Lunar geophysics, geodesy, and dynamics

Science.gov (United States)

Williams, J. G.; Dickey, J. O.

2002-01-01

Experience with the dynamics and data analyses for earth and moon reveals both similarities and differences. Analysis of Lunar Laser Ranging (LLR) data provides information on the lunar orbit, rotation, solid-body tides, and retroreflector locations.

Reaction of strontium zirconate with refractory borides and carbides

International Nuclear Information System (INIS)

Bowker, J.C.; Lane, J.E.

1990-01-01

The chemical compatibility of the potential oxide ceramic matrix material, strontium zirconate, and several different potential nonoxide ceramic reinforcement materials was studied by elevated temperature reaction. Results are presented in this paper

3-D Characterization of Detrital Zircon Grains and its Implications for Fluvial Transport, Mixing, and Preservation Bias

Science.gov (United States)

Markwitz, V.; Kirkland, C. L.; Mehnert, A.; Gessner, K.; Shaw, J.

2017-12-01

Detrital zircon studies can suffer from selective loss of provenance information due to U-Pb age discordance, metamictization, metamorphic overprinting and fluviatile transport processes. The relationship between isotopic composition and zircon grain shape, and how grain shape is modified during transport, is largely unknown. We combine X-ray tomography with U-Pb geochronology to quantify how fluvial transport affects 3-D zircon shape, detrital age signature, and grain density along the Murchison River, whose catchment comprises Eoarchean to Early Paleozoic source rocks in Western Australia. We acquired tomographic volumes and isotopic data from 373 detrital zircons to document changes in size, shape and density in transport direction, and explore how grain shape, age spectra and the proportion of discordant material vary along the channel. Results show that shape characteristics are sensitive to transport distance, stream gradient, proximity to source material, and whether the source consists of primary or recycled zircons. With increasing transport distance, grain lengths decrease more than their widths. Furthermore, the loss of metamict grains occurs at a near constant rate, resulting in a linear increase of mean calculated zircon density by ca. 0.03 g/cm3 per 100 km transport distance. 3-D grain shape is therefore strongly linked to detrital age signature, and mean grain density is a function of the absolute transport distance. 3-D shape characteristics provide valuable information on detrital zircon populations, including the interaction between source materials with fluvial transport processes, which significantly affects preservation bias and, by inference, the representativeness of the sampled data.

The roles and functions of a lunar base Nuclear Technology Center

International Nuclear Information System (INIS)

Buden, D.; Angelo, J.A. Jr.

1991-01-01

This paper describes the roles and functions of a special Nuclear Technology Center which is developed as an integral part of a permanent lunar base. Numerous contemporary studies clearly point out that nuclear energy technology will play a major role in any successful lunar/Mars initiative program and in the overall establishment of humanity's solar system civilization. The key role of nuclear energy in the providing power has been recognized. A Nuclear Technology Center developed as part of of a permanent lunar base can also help bring about many other nuclear technology applications, such as producing radioisotopes for self-illumination, food preservation, waste sterilization, and medical treatment; providing thermal energy for mining, materials processing and agricultural; and as a source of emergency habitat power. Designing such a center will involve the deployment, operation, servicing and waste product management and disposal of megawatt class reactor power plants. This challenge must be met with a minimum of direct human support at the facility. Furthermore, to support the timely, efficient integration of this Nuclear Technology Center in the evolving lunar base infrastructure, an analog of such a facility will be needed here on Earth. 12 refs., 4 figs., 1 tab

Pressure-induced phase transformation in zircon-type orthovanadate SmVO4 from experiment and theory

International Nuclear Information System (INIS)

Popescu, C; Garg, Alka B; Errandonea, D; Sans, J A; Rodriguez-Hernández, P; Radescu, S; Muñoz, A; Achary, S N; Tyagi, A K

2016-01-01

The compression behavior of zircon-type samarium orthovanadate, SmVO 4 , has been investigated using synchrotron-based powder x-ray diffraction and ab initio calculations of up to 21 GPa. The results indicate the instability of ambient zircon phase at around 6 GPa, which transforms to a high-density scheelite-type phase. The high-pressure phase remains stable up to 21 GPa, the highest pressure reached in the present investigations. On pressure release, the scheelite phase is recovered. The crystal structure of the high-pressure phase and the equations of state for the zircon- and scheelite-type phases have been determined. Various compressibilities, such as the bulk, axial and bond compressibilities, estimated from the experimental data are found to be in good agreement with the results obtained from theoretical calculations. The calculated elastic constants show that the zircon structure becomes mechanically unstable beyond the transition pressure. Overall there is good agreement between the experimental and theoretical findings. (paper)

Lunar and Planetary Science XXXV: Moon and Mercury

Science.gov (United States)

2004-01-01

The session" Moon and Mercury" included the following reports:Helium Production of Prompt Neutrinos on the Moon; Vapor Deposition and Solar Wind Implantation on Lunar Soil-Grain Surfaces as Comparable Processes; A New Lunar Geologic Mapping Program; Physical Backgrounds to Measure Instantaneous Spin Components of Terrestrial Planets from Earth with Arcsecond Accuracy; Preliminary Findings of a Study of the Lunar Global Megaregolith; Maps Characterizing the Lunar Regolith Maturity; Probable Model of Anomalies in the Polar Regions of Mercury; Parameters of the Maximum of Positive Polarization of the Moon; Database Structure Development for Space Surveying Results by Moon -Zond Program; CM2-type Micrometeoritic Lunar Winds During the Late Heavy Bombardment; A Comparison of Textural and Chemical Features of Spinel Within Lunar Mare Basalts; The Reiner Gamma Formation as Characterized by Earth-based Photometry at Large Phase Angles; The Significance of the Geometries of Linear Graben for the Widths of Shallow Dike Intrusions on the Moon; Lunar Prospector Data, Surface Roughness and IR Thermal Emission of the Moon; The Influence of a Magma Ocean on the Lunar Global Stress Field Due to Tidal Interaction Between the Earth and Moon; Variations of the Mercurian Photometric Relief; A Model of Positive Polarization of Regolith; Ground Truth and Lunar Global Thorium Map Calibration: Are We There Yet?;and Space Weathering of Apollo 16 Sample 62255: Lunar Rocks as Witness Plates for Deciphering Regolith Formation Processes.

Detrital zircon geochronology and provenance of the Chubut Group in the northeast of Patagonia, Argentina

Science.gov (United States)

Navarro, Edgardo L.; Astini, Ricardo A.; Belousova, Elena; Guler, M. Verónica; Gehrels, George

2015-11-01

The Chubut Group constitutes the most widespread sedimentary unit in NE Patagonia, characterized by variable-energy fluvial deposits. U-Pb analysis of detrital zircons from two sections of the Chubut Group constraint the age of the oldest sedimentary rocks in the northeast of the Somuncurá - Cañadón Asfalto Basin. In the Cañadón Williams area, at San Jorge section, 20 km NW of Telsen locality, dating of 56 detrital zircons from a medium to coarse sandstone indicated a maximum depositional age of 109 ± 1 Ma (n = 4). These sandstones were interpreted to represent shallow channels, associated with a lacustrine system. In the Telsen locality, a laser ablation analysis of 115 detrital zircons from a medium to coarse-grained sandstone, from fluvial channel facies, yielded a maximum depositional age of ca. 106 ± 1 Ma (n = 8). Both ages are consistent with volcanic events of the Barremian to Albian age in the central Patagonian Andes Region. Cathodoluminescence images of zircons from the San Jorge sample suggest an igneous origin, which is further supported by Th/U values above 0.5 in most of the grains. The distribution of the statistical modes of the main age populations of detrital zircons for the two samples [182, 185 and 189 Ma for Telsen sample (T2S) and 181 ± 1 Ma for San Jorge sample (SJS)] matches the age of the volcanic Marifil Formation. The rocks of the Marifil Formation of these ages are exposed NE to SE of the study area. The abundance of zircons of similar Jurassic ages (n = 52 for SJS and n = 105 for T2S) and the external morphology of the zircons in the sample SJS, implies a close proximity of the source area. Suggestion that the Marifil Formation was the main provenance source is also supported by northeast-southeasterly paleocurrents measured at the San Jorge and Telsen sections.

Do Zircon age Spectra Record Magmatic Cyclicity at Soufrière (Saint Lucia, Lesser Antilles)?

Science.gov (United States)

Schmitt, A. K.; Stockli, D. F.; Lindsay, J. M.

2007-12-01

The Soufrière Volcanic Center (Saint Lucia, Lesser Antilles) is a long-lived arc-volcanic system that evolved over the past 5 - 6 Ma. Its most recent volcanic activity between 20 and 40 ka was concentrated within the prominent Qualibou topographic depression and produced two voluminous pyroclastic deposits: Choiseul and the overlying Belfond. In addition, several dacitic lava domes exist within the Qualibou depression. Because evidence of earlier volcanic activity in long-lived magma systems is frequently obliterated by subsequent eruptive or volcano-tectonic events, high spatial resolution U-Th dating of zircon combined with (U-Th)/He dating is a powerful tool to identify magma crystallization episodes at depth and to link these to the eruptive record. U-Th model ages and disequilibrium corrected U-Pb ages for 56 individual zircons from Soufrière lavas (Morne Bonin, Belfond, Terre Blanche) and pumice (Choiseul, Belfond) were determined by secondary ionization mass spectrometry. The majority of results is on unpolished zircons where analysis pits integrate over the outermost ~10 μm of individual grains with a lateral spatial resolution of ~40 μm. Selected grains were subsequently analyzed by (U-Th)/He methods. Belfond and Terre Blanche (U-Th)/He zircon ages (~20 ka) agree with previous 14C charcoal ages, whereas Morne Bonin ages are much older (~250 ka). Overall, the U-Th zircon crystallization age spectrum reveals a remarkable range between ~20 and ~600 ka and displays multiple peaks, among which the most prominent are tentatively identified at ~40 ka, ~80 ka, ~130 ka, ~200 ka and ~500 ka. The distribution of rim ages indicates that most zircons lack overgrowth dating from just prior to the eruption, but the youngest ages for each sample overlap with the eruption ages. Soufrière zircons thus reveal magma intrusion, cooling, and crystallization cycles within the underlying plutonic system for which the volcanic stratigraphic record is sketchy.

Petrologic Characteristics of the Lunar Surface.

Science.gov (United States)

Wang, Xianmin; Pedrycz, Witold

2015-11-27

Petrologic analysis of the lunar surface is critical for determining lunar formation and evolution. Here, we report the first global petrologic map that includes the five most important lunar lithological units: the Ferroan Anorthositic (FAN) Unit, the Magnesian Suite (MS) Unit, the Alkali Suite (AS) Unit, the KREEP Basalt (KB) Unit and the Mare Basalt (MB) Unit. Based on the petrologic map and focusing on four long-debated and important issues related to lunar formation and evolution, we draw the following conclusions from the new insights into the global distribution of the five petrologic units: (1) there may be no petrogenetic relationship between MS rocks and KB; (2) there may be no petrogenetic link between MS and AS rocks; (3) the exposure of the KREEP component on the lunar surface is likely not a result of MB volcanism but is instead mainly associated with the combined action of plutonic intrusion, KREEP volcanism and celestial collision; (4) the impact size of the South Pole-Aitken basin is constrained, i.e., the basin has been excavated through the whole crust to exhume a vast majority of lower-crustal material and a very limited mantle components to the lunar surface.

Fatigue-free lead zirconate titanate-based capacitors for nonvolatile memories

International Nuclear Information System (INIS)

Shannigrahi, S. R.; Jang, Hyun M.

2001-01-01

The development of lead zirconate titanate (PZT)-based capacitors has been a long time goal of ferroelectric random access memories (FRAM). However, PZT-based perovskites with common platinum (Pt) electrodes have suffered from a significant reduction of the remanent polarization (P r ) after a certain number of read/write cycles (electrical fatigue). We now report the development of fatigue-free lanthanum-modified PZT capacitors using common Pt electrodes. The capacitors fabricated at 580 o C by applying a PZT seed layer exhibited fatigue-free behavior up to 6.5 x 10 10 switching cycles, a quite stable charge retention profile with time, and comparatively high P r values, all of which assure their suitability for practical FRAM applications. Copyright 2001 American Institute of Physics

Mechanisms and timescales of generating eruptible rhyolitic magmas at Yellowstone caldera from zircon and sanidine geochronology and geochemistry

Science.gov (United States)

Stelten, Mark; Cooper, Kari M.; Vazquez, Jorge A.; Calvert, Andrew T.; Glessner, Justin G

2015-01-01

We constrain the physical nature of the magma reservoir and the mechanisms of rhyolite generation at Yellowstone caldera via detailed characterization of zircon and sanidine crystals hosted in three rhyolites erupted during the (ca. 170 – 70 ka) Central Plateau Member eruptive episode – the most recent post-caldera magmatism at Yellowstone. We present 238U-230Th crystallization ages and trace-element compositions of the interiors and surfaces (i.e., unpolished rims) of individual zircon crystals from each rhyolite. We compare these zircon data to 238U- 230Th crystallization ages of bulk sanidine separates coupled with chemical and isotopic data from single sanidine crystals. Zircon age and trace-element data demonstrate that the magma reservoir that sourced the Central Plateau Member rhyolites was long-lived (150 – 250 kyr) and genetically related to the preceding episode of magmatism, which occurred ca. 256 ka. The interiors of most zircons in each rhyolite were inherited from unerupted material related to older stages of Central Plateau Member magmatism or the preceding late Upper Basin Member magmatism (i.e., are antecrysts). Conversely, most zircon surfaces crystallized near the time of eruption from their host liquids (i.e., are autocrystic). The repeated recycling of zircon interiors from older stages of magmatism demonstrates that sequentially erupted Central Plateau Member rhyolites are genetically related. Sanidine separates from each rhyolite yield 238U-230Th crystallization ages at or near the eruption age of their host magmas, coeval with the coexisting zircon surfaces, but are younger than the coexisting zircon interiors. Chemical and isotopic data from single sanidine crystals demonstrate that the sanidines in each rhyolite are in equilibrium with their host melts, which considered along with their near-eruption crystallization ages suggests that nearly all CPM sanidines are autocrystic. The paucity of antecrystic sanidine crystals relative to

Isotope, scanning electron microscope, and energy dispersive spectrometer studies of heterogeneous zircons from radioactive granites in the Grenville structural province, Quebec and Ontario

International Nuclear Information System (INIS)

Rimsaite, J.

1981-01-01

Heterogeneous zircons yielded discordant Pb-U, Pb-Th, and 207 Pb- 206 Pb isotopic ages. Most data points fall below the concordia curve, implying losses of daughter elements, bqt they define a discordia line that intersects the concordia at approximately 90 Ma and 1020 Ma. To obtain evidence for mobilization of U and radiogenic Pb, zircon grains were studied using a scanning electron microscope coupled with an energy dispersive spectrometer. High magnification backscattered and secondary electron images of the zircon revealed narrow fractures, zoning and diverse mineral inclusions. Three groups of mineral inclusions observed were: 1) those predating zoned zircon and apparently serving as a nucleus; 2) uraninite, feldspar, and apatite associated with the growth and zoning of the host zircon; and 3) fracture-fillings that postdate crystallization of the host zircon. The U- and Pb-rich inclusions incorporated into the zircon grains during and after its crystallization markedly affect isotopic ages of the host zircon. Migration of Pb and U have occurred along fractures in zircon. Zircon, uraninite, and other associated minerals have decomposed and complex reactions have taken place between the liberated Zr, U, Th and other elements to produce overgrowths on mineral grains and unidentified Zr-bearing material in fractures

Possible Applications of Photoautotrophic Biotechnologies at Lunar Settlements

Science.gov (United States)

McKay, David S.; Allen, Carl; Jones, J. A.; Bayless, D.; Brown, I.; Sarkisova, S.; Garrison, D.

2007-01-01

The most ambitious goal of the Vision of Space Exploration is to extend human presence across the solar system. Today, however, missions would have to bring all of the propellant, air, food, water, habitable volumes and shielding needed to sustain settlers beyond Earth. That is why resources for propellants, life support and construction of support systems and habitats must be found in space and utilized if humans hope to ever explore and colonize the solar system. The life support, fuel production and material processing systems currently proposed for spaceflight are essentially disconnected. Only traditional crop production has been proposed as a segment for bioregenerative life support systems, although the efficiency of higher plants for air regeneration is generally low. Thus, the investigation of air bioregeneration techniques based on the activity of photosynthetic organisms with higher rates of CO2 scrubbing and O2 release is very timely and important. Future systems for organic waste utilization in space may also benefit from the use of specific microorganisms. This janitorial job is efficiently carried out by microbes on Earth, which drive and connect different elemental cycles. It is likely that environmental control and life support systems based on bioregeneration will be capable of converting both organic and inorganic components of the waste at lunar settlements into edible biomass. The most challenging technologies for future lunar settlements are the extraction of elements (e.g. Fe, O, Si, etc) from local rocks for industrial feedstocks and the production of propellants. While such extraction can be accomplished by purely inorganic processes, the high energy requirements of such processes motivates the search for alternative technologies with lower energy requirements and appropriate efficiency. Well-developed terrestrial industrial biotechnologies for metals extraction and conversion could therefore be the prototypes for extraterrestrial

The Future Lunar Flora Colony

Science.gov (United States)

Goel, E. G.; Guven, U. G.

2017-10-01

A constructional design for the primary establishment for a lunar colony using the micrometeorite rich soil is proposed. It highlights the potential of lunar regolith combined with Earth technology for water and oxygen for human outposts on the Moon.

On the valency state of radiogenic lead in zircon and its consequences

DEFF Research Database (Denmark)

Kramers, J.; Frei, Robert; Newville, M.

2009-01-01

nucleus comes to rest. Further, a zircon grain, being small, should remain highly oxidizing in its interior by the constant loss of ß-particles, maintaining the 4+ state of radiogenic Pb. From its effective ion radius, similar to that of Zr4+, and its charge, Pb4+ has to be compatible in the zircon...... not resemble that of PbO2. The arguments why radiogenic Pb should be tetravalent are based on analogies with studies relating to the tetravalent state of 234Th and the hexavalent state of 234U, which show that a-recoil in silicates generates a strongly oxidizing environment at the site where the recoiling......-recoil damaged sites could be leached out by any electrolyte solution that reduces it to the divalent state, making it both incompatible and soluble. Thus, discordia can be generated in weathering. The curious observation that discordant Archaean zircon suites generally define trends to lower intercepts at up...

Moon 101: Introducing Students to Lunar Science and Exploration

Science.gov (United States)

Shaner, A. J.; Shipp, S. S.; Allen, J. S.; Kring, D. A.

2011-12-01

Moon 101 is designed with the purpose of familiarizing students with lunar geology and exploration. Armed with guiding questions, students read articles covering various lunar science topics and browse images from past and current lunar missions to familiarize themselves with available lunar data sets. Moon 101 was originally created for high school students preparing to conduct open-inquiry, lunar research. Most high school students' knowledge of lunar science is limited to lunar phases and tides, and their knowledge of lunar exploration is close to non-existent. Moon 101 provides a summary of the state of knowledge of the Moon's formation and evolution, and the exploration that has helped inform the lunar science community. Though designed for high school students, Moon 101 is highly appropriate for the undergraduate classroom, especially at the introductory level where resources for teaching lunar science are scarce. Moon 101 is comprised of two sections covering lunar science (formation and geologic evolution of the Moon) and one section covering lunar exploration. Students read information on the formation and geologic evolution of the Moon from sources such as the Planetary Science Research Discoveries (PSRD) website and the USGS professional paper A Geologic History of the Moon by Wilhelms. While these resources are not peer-reviewed journals, the information is presented at a level more advanced than articles from newspapers and popular science magazines. This ensures that the language is accessible to students who do not have a strong lunar/planetary science background, or a strong science background in general. Formation readings include information on older and current formation hypotheses, including the Giant Impact Hypothesis, the Magma Ocean hypothesis, and the age of the lunar crust. Lunar evolution articles describe ideas such as the Late Heavy Bombardment and geologic processes such as volcanism and impact cratering. After reading the articles

U-Pb ages and Hf isotope compositions of zircons in plutonic rocks from the central Famatinian arc, Argentina

Science.gov (United States)

Otamendi, Juan E.; Ducea, Mihai N.; Cristofolini, Eber A.; Tibaldi, Alina M.; Camilletti, Giuliano C.; Bergantz, George W.

2017-07-01

The Famatinian arc formed around the South Iapetus rim during the Ordovician, when oceanic lithosphere subducted beneath the West Gondwana margin. We present combined in situ U-Th-Pb and Lu-Hf isotope analyses for zircon to gain insights into the origin and evolution of Famatinian magmatism. Zircon crystals sampled from four intermediate and silicic plutonic rocks confirm previous observations showing that voluminous magmatism took place during a relatively short pulse between the Early and Middle Ordovician (472-465 Ma). The entire zircon population for the four plutonic rocks yields coherent εHf negative values and spreads over several ranges of initial εHf(t) units (-0.3 to -8.0). The range of εHf units in detrital zircons of Famatinian metasedimentary rocks reflects a prolonged history of the cratonic sources during the Proterozoic to the earliest Phanerozoic. Typical tonalites and granodiorites that contain zircons with evolved Hf isotopic compositions formed upon incorporating (meta)sedimentary materials into calc-alkaline metaluminous magmas. The evolved Hf isotope ratios of zircons in the subduction related plutonic rocks strongly reflect the Hf isotopic character of the metasedimentary contaminant, even though the linked differentiation and growth of the Famatinian arc crust was driven by ascending and evolving mantle magmas. Geochronology and Hf isotope systematics in plutonic zircons allow us understanding the petrogenesis of igneous series and the provenance of magma sources. However, these data could be inadequate for computing model ages and supporting models of crustal evolution.

Academic Aspects of Lunar Water Resources and Their Relevance to Lunar Protolife

Directory of Open Access Journals (Sweden)

Jack Green

2011-09-01

Full Text Available Water ice has been discovered on the moon by radar backscatter at the North Pole and by spectrometry at the South Pole in the Cabeus crater with an extrapolated volume for both poles of conservatively 109 metric tons. Various exogenic and endogenic sources of this water have been proposed. This paper focuses on endogenic water sources by fumaroles and hot springs in shadowed polar craters. A survey of theoretical and morphological details supports a volcanic model. Release of water and other constituents by defluidization over geological time was intensified in the Hadean Eon (c.a. 4600 to 4000 My. Intensification factors include higher heat flow by now-extinct radionuclides, tidal flexing and higher core temperatures. Lesser gravity would promote deeper bubble nucleation in lunar magmas, slower rise rates of gases and enhanced subsidence of lunar caldera floors. Hadean volcanism would likely have been more intense and regional in nature as opposed to suture-controlled location of calderas in Phanerozoic Benioff-style subduction environments. Seventy-seven morphological, remote sensing and return sample features were categorized into five categories ranging from a volcano-tectonic origin only to impact origin only. Scores for the most logical scenario were 69 to eight in favor of lunar volcanism. Ingredients in the Cabeus plume analysis showed many volcanic fluids and their derivatives plus a large amount of mercury. Mercury-rich fumaroles are well documented on Earth and are virtually absent in cometary gases and solids. There are no mercury anomalies in terrestrial impact craters. Volcanic fluids and their derivatives in lunar shadow can theoretically evolve into protolife. Energy for this evolution can be provided by vent flow charging intensified in the lunar Hadean and by charge separation on freezing fumarolic fluids in shadow. Fischer-Tropsch reactions on hydrothermal clays can yield lipids, polycyclic aromatic hydrocarbons and amino

On the lunar node resonance of the orbital plane evolution of the Earth's satellite orbits

Science.gov (United States)

Zhu, Ting-Lei

2018-06-01

This paper aims to investigate the effects of lunar node resonance on the circular medium Earth orbits (MEO). The dynamical model is established in classical Hamiltonian systems with the application of Lie transform to remove the non-resonant terms. Resonant condition, stability and phase structures are studied. The lunar node resonance occurs when the secular changing rates of the orbital node (with respect to the equator) and the lunar node (with respect to the ecliptic) form a simple integer ratio. The resonant conditions are satisfied for both inclined and equatorial orbits. The orbital plane would have long period (with typical timescales of several centuries) fluctuation due to the resonance.

Dating of zircon from high-grade rocks: Which is the most reliable method?

Directory of Open Access Journals (Sweden)

Alfred Kröner

2014-07-01

Full Text Available Magmatic zircon in high-grade metamorphic rocks is often characterized by complex textures as revealed by cathodoluminenscence (CL that result from multiple episodes of recrystallization, overgrowth, Pb-loss and modifications through fluid-induced disturbances of the crystal structure and the original U-Th-Pb isotopic systematics. Many of these features can be recognized in 2-dimensional CL images, and isotopic analysis of such domains using a high resolution ion-microprobe with only shallow penetration of the zircon surface may be able to reconstruct much of the magmatic and complex post-magmatic history of such grains. In particular it is generally possible to find original magmatic domains yielding concordant ages. In contrast, destructive techniques such as LA-ICP-MS consume a large volume, leave a deep crater in the target grain, and often sample heterogeneous domains that are not visible and thus often yield discordant results which are difficult to interpret. We provide examples of complex magmatic zircon from a southern Indian granulite terrane where SHRIMP II and LA-ICP-MS analyses are compared. The SHRIMP data are shown to be more precise and reliable, and we caution against the use of LA-ICP-MS in deciphering the chronology of complex zircons from high-grade terranes.

Pb-Pb zircon ages of the Porto Nacional high-grade metamorphic terrain, northern portion of the Goias Massif, central Brazil

Energy Technology Data Exchange (ETDEWEB)

Gorayeb, Paulo Sergio de Sousa; Moura, Candido Augusto Veloso [Para Univ., Belem, PA (Brazil). Centro de Geociencias]. E-mail: gorayebp@ufpa.br; c_moura@ufpa.br; Barros, Gisele Ribeiro de [Para Univ., Belem, PA (Brazil). Programa Institucional de Bolsas de Iniciacao Cientifica (PIBIC)]. E-mail: agbarros@amazon.com.br

2000-03-01

Single zircon Pb-evaporation ages were determined for a mafic granulite, two enderbites and a kinzigite of the Porto Nacional High-Grade Metamorphic Terrain (PNHGT) in the Goias massif. Zircons from mafic granulites and one of the enderbites of yielded average {sup 207} Pb/{sup 206} Pb ages of 2125{+-}3 Ma and 2153{+-}1 Ma, respectively, being interpreted as minimum ages of the igneous protoliths. The other enderbite, whose zircons presented round terminations, yielded an average {sup 207} Pb/{sup 206} Pb age of 2097 {+-} 2 Ma. Zircons from the kinzigite, displaying cores and rims overgrowth, presented {sup 207} Pb/{sup 206} Pb ages ranging between 2027 and 2115 Ma. However, a very homogeneous zircon crystal without overgrowth yielded age of 2100 {+-} 2 Ma, with a distinctive low Th/U value (0.02). This zircon is interpreted as a metamorphic crystal and its age probably sets the age of the granulite facies metamorphism, indicating that the PNHGT is a result of the Transamazonian thermotectonic event. (author)

A Change in Igneous Activity of the Jack Hills Zircon Sources ca. 3.9 Ga

Science.gov (United States)

Bell, E. A.; Harrison, T. M.

2010-12-01

New Ti-in-zircon crystallization temperature (Txlln) data for Jack Hills zircons reveal that the tight clustering of Hadean grains around a Txlln of 680°C, possibly indicative of felsic-to-intermediate minimum melting conditions, continues to ~3.92 Ga. Between 3.92-3.82 Ga the 680°C clustering ceases and most concordant grains cluster around an apparent Txlln of 610°C. A small group of zircons with higher Txlln (~750°C), present during the Hadean, is also observed during this period. After 3.82 Ga a Hadean-like distribution resumes for ~100 Ma. This large, concordant, low-Ti group at ~3.9 Ga is statistically distinct from the Hadean distribution and appears to be unique in the Jack Hills zircon record. The existence of coeval high- and low-Ti groups suggests that two distinct zircon-forming processes are distinguishable ~3.9 Ga, unlike during the Hadean. The significant numbers of zircons with apparent Txlln below 600°C may be suggestive of subsolidus formation, since igneous units with solidii below 600°C are relatively rare. The higher-Ti group is more consistent with an intermediate to mafic igneous origin but metamorphic overprinting or subsolidus formation at granulite grade cannot be ruled out by Txlln alone. A substantial proportion of the high-Ti group display oscillatory and disrupted oscillatory zoning in cathodoluminescence images, usually indicative of igneous origins and later metamorphism, respectively; most low-Ti grains are homogeneous. Several of each group display patchy zonation indicative of metamorphic overprinting. Although several grains with apparent Txlln >600°C display oscillatory zonation, the majority of the low-Ti group do not show textural evidence for igneous origins. We interpret these results to indicate the transition from a mechanism(s) that produced dominantly 680°C apparent zircon temperatures at ca. 3.9 Ga to include a new zircon-forming process in the sediment source(s), likely a protracted period of metamorphism

Basic radio interferometry for future lunar missions

NARCIS (Netherlands)

Aminaei, Amin; Klein Wolt, Marc; Chen, Linjie; Bronzwaer, Thomas; Pourshaghaghi, Hamid Reza; Bentum, Marinus Jan; Falcke, Heino

2014-01-01

In light of presently considered lunar missions, we investigate the feasibility of the basic radio interferometry (RIF) for lunar missions. We discuss the deployment of two-element radio interferometer on the Moon surface. With the first antenna element is envisaged to be placed on the lunar lander,

Constraints on the timing of multiple thermal events and re-equilibration recorded by high-U zircon and xenotime: Case study of pegmatite from Piława Górna (Góry Sowie Block, SW Poland)

Science.gov (United States)

Budzyń, Bartosz; Sláma, Jiří; Kozub-Budzyń, Gabriela A.; Konečný, Patrik; Holický, Ivan; Rzepa, Grzegorz; Jastrzębski, Mirosław

2018-06-01

The application of zircon and xenotime geochronometers requires knowledge of their potential and limitations related to possible disturbance of the age record. The alteration of the intergrown zircon and xenotime in pegmatite from the Góry Sowie Block (SW Poland) was studied using the electron microprobe analysis, X-ray WDS compositional mapping, micro-Raman analysis, and LA-ICP-MS U-Pb dating of zircon and xenotime, as well as the U-Th-total Pb dating of uraninite. These microanalytical techniques were applied to understand the formation mechanisms of the secondary textures related to post-magmatic processes in the zircon and xenotime intergrowth, and to constrain their timing. Textural and compositional features combined with U-Pb data indicate that the pegmatite-related crystallization of the zircon and xenotime intergrowth occurred ca. 2.09 Ga (2086 ± 35 Ma for zircon and 2093 ± 52 Ma for xenotime), followed by the re-equilibration of zircon and xenotime ca. 370 Ma (373 ± 18 Ma and 368 ± 6 Ma, respectively) during the formation of the younger pegmatite. The zircon and xenotime were most likely derived from Precambrian basement rocks and emplaced in the pegmatite as a restite. The zircon preserved textures related to diffusion-reaction processes that affected its high-U core (up to ca. 9.6 wt% UO2), which underwent further metamictization and amorphization due to self-radiation damage. The zircon rim and xenotime were affected by coupled dissolution-reprecipitation processes that resulted in patchy zoning, age disturbance and sponge-like textures. Xenotime was also partially replaced by fluorapatite or hingganite-(Y) and Y-enriched allanite-(Ce). The termination of the low-temperature alteration was constrained by the U-Th-total Pb age of the uraninite inclusions that crystallized in zircon at 281 ± 2 Ma, which is consistent with the age of 278 ± 15 Ma obtained from the youngest cluster of U-Pb ages in the re-equilibrated high-U zircon domains. This study

Educating the Next Generation of Lunar Scientists

Science.gov (United States)

Shaner, A. J.; Shipp, S. S.; Allen, J. S.; Kring, D. A.

2010-12-01

The Center for Lunar Science and Exploration (CLSE), a collaboration between the Lunar and Planetary Institute (LPI) and NASA’s Johnson Space Center (JSC), is one of seven member teams of the NASA Lunar Science Institute (NLSI). In addition to research and exploration activities, the CLSE team is deeply invested in education and outreach. In support of NASA’s and NLSI’s objective to train the next generation of scientists, CLSE’s High School Lunar Research Project is a conduit through which high school students can actively participate in lunar science and learn about pathways into scientific careers. The High School Lunar Research Project engages teams of high school students in authentic lunar research that envelopes them in the process of science and supports the science goals of the CLSE. Most high school students’ lack of scientific research experience leaves them without an understanding of science as a process. Because of this, each team is paired with a lunar scientist mentor responsible for guiding students through the process of conducting a scientific investigation. Before beginning their research, students undertake “Moon 101,” designed to familiarize them with lunar geology and exploration. Students read articles covering various lunar geology topics and analyze images from past and current lunar missions to become familiar with available lunar data sets. At the end of “Moon 101”, students present a characterization of the geology and chronology of features surrounding the Apollo 11 landing site. To begin their research, teams choose a research subject from a pool of topics compiled by the CLSE staff. After choosing a topic, student teams ask their own research questions, within the context of the larger question, and design their own research approach to direct their investigation. At the conclusion of their research, teams present their results and, after receiving feedback, create and present a conference style poster to a panel of

The simulation of lunar gravity field recovery from D-VLBI of Chang’E-1 and SELENE lunar orbiters

Science.gov (United States)

Yan, Jianguo; Ping, Jingsong; Matsumoto, K.; Li, Fei

2008-07-01

The lunar gravity field is a foundation to study the lunar interior structure, and to recover the evolution history of the Moon. It is still an open and key topic for lunar science. For above mentioned reasons, it becomes one of the important scientific objectives of recent lunar missions, such as KAGUYA (SELENE) the Japanese lunar mission and Chang’E-1, the Chinese lunar mission. The Chang’E-1 and the SELENE were successfully launched in 2007. It is estimated that these two missions can fly around the Moon longer than 6 months simultaneously. In these two missions, the Chinese new VLBI (Very Long Baseline Interferometry) network will be applied for precise orbit determination (POD) by using a differential VLBI (D-VLBI) method during the mission period. The same-beam D-VLBI technique will contribute to recover the lunar gravity field together with other conventional observables, i.e. R&RR (Range and Range Rate) and multi-way Doppler. Taking VLBI tracking conditions into consideration and using the GEODYNII/SOVLE software of GSFC/NASA/USA [Rowlands, D.D., Marshall, J.A., Mccarthy, J., et al. GEODYN II System Description, vols. 1 5. Contractor Report, Hughes STX Corp. Greenbelt, MD, 1997; Ullman, R.E. SOLVE program: mathematical formulation and guide to user input, Hughes/STX Contractor Report, Contract NAS5-31760. NASA Goddard Space Flight Center, Greenbelt, Maryland, 1994], we simulated the lunar gravity field recovering ability with and without D-VLBI between the Chang’E-1 and SELENE main satellite. The cases of overlapped flying and tracking period of 30 days, 60 days and 90 days have been analyzed, respectively. The results show that D-VLBI tracking between two lunar satellites can improve the gravity field recovery remarkably. The results and methods introduced in this paper will benefit the actual missions.

Reference reactor module for NASA's lunar surface fission power system

International Nuclear Information System (INIS)

Poston, David I.; Kapernick, Richard J.; Dixon, David D.; Werner, James; Qualls, Louis; Radel, Ross

2009-01-01

Surface fission power systems on the Moon and Mars may provide the first US application of fission reactor technology in space since 1965. The Affordable Fission Surface Power System (AFSPS) study was completed by NASA/DOE to determine the cost of a modest performance, low-technical risk surface power system. The AFSPS concept is now being further developed within the Fission Surface Power (FSP) Project, which is a near-term technology program to demonstrate system-level TRL-6 by 2013. This paper describes the reference FSP reactor module concept, which is designed to provide a net power of 40 kWe for 8 years on the lunar surface; note, the system has been designed with technologies that are fully compatible with a Martian surface application. The reactor concept uses stainless-steel based. UO 2 -fueled, pumped-NaK fission reactor coupled to free-piston Stirling converters. The reactor shielding approach utilizes both in-situ and launched shielding to keep the dose to astronauts much lower than the natural background radiation on the lunar surface. The ultimate goal of this work is to provide a 'workhorse' power system that NASA can utilize in near-term and future Lunar and Martian mission architectures, with the eventual capability to evolve to very high power, low mass systems, for either surface, deep space, and/or orbital missions.

Lunar surface exploration using mobile robots

Science.gov (United States)

Nishida, Shin-Ichiro; Wakabayashi, Sachiko

2012-06-01

A lunar exploration architecture study is being carried out by space agencies. JAXA is carrying out research and development of a mobile robot (rover) to be deployed on the lunar surface for exploration and outpost construction. The main target areas for outpost construction and lunar exploration are mountainous zones. The moon's surface is covered by regolith. Achieving a steady traversal of such irregular terrain constitutes the major technical problem for rovers. A newly developed lightweight crawler mechanism can effectively traverse such irregular terrain because of its low contact force with the ground. This fact was determined on the basis of the mass and expected payload of the rover. This paper describes a plan for Japanese lunar surface exploration using mobile robots, and presents the results of testing and analysis needed in their development. This paper also gives an overview of the lunar exploration robot to be deployed in the SELENE follow-on mission, and the composition of its mobility, navigation, and control systems.

Lunar nitrogen: Secular variation or mixing?

International Nuclear Information System (INIS)

Norris, S.J.; Wright, I.P.; Pillinger, C.T.

1986-01-01

The two current models to explain the nearly 40% variation of the lunar nitrogen isotopic composition are: (1) secular variation of solar wind nitrogen; and (2) a two component mixing model having a constant, heavy solar wind admixed with varying amounts of indigenous light lunar N (LLN). Both models are needed to explain the step pyrolysis extraction profile. The secular variation model proposes that the low temperature release is modern day solar wind implanted into grain surfaces, the 900 C to 1100 C release is from grain surfaces which were once exposed to the ancient solar wind but which are now trapped inside agglutinates, and the >1100 C release as spallogenic N produced by cosmic rays. The mixing model ascribes the components to solar wind, indigenous lunar N and spallogenic N respectively. An extension of either interpretation is that the light N seen in lunar breccias or deep drill cores represent conditions when more N-14 was available to the lunar surface

A lunar polar expedition

Science.gov (United States)

Dowling, Richard; Staehle, Robert L.; Svitek, Tomas

1992-09-01

Advanced exploration and development in harsh environments require mastery of basic human survival skill. Expeditions into the lethal climates of Earth's polar regions offer useful lessons for tommorrow's lunar pioneers. In Arctic and Antarctic exploration, 'wintering over' was a crucial milestone. The ability to establish a supply base and survive months of polar cold and darkness made extensive travel and exploration possible. Because of the possibility of near-constant solar illumination, the lunar polar regions, unlike Earth's may offer the most hospitable site for habitation. The World Space Foundation is examining a scenario for establishing a five-person expeditionary team on the lunar north pole for one year. This paper is a status report on a point design addressing site selection, transportation, power, and life support requirements.

Simultaneous determinations of U-Pb age and REE abundances for zircons using AfF excimer laser ablation-ICPMS

International Nuclear Information System (INIS)

Iizuka, Tsuyoshi; Hirata, Takafumi

2004-01-01

Using a laser-ablation-inductively coupled plasma mass spectrometer (LA-ICPMS), U-Pb age and rare earth element (REE) abundances have been determined simultaneously from a single 20 μm ablation pit of zircon. The laser ablation system utilizing 193 nm wave-length ArF excimer laser produces stable and reproducible signal intensities resulted in good precisions on measurements of element concentrations and isotopic ratios. Because of the higher energy density of the deep ultra-violet laser beam, ablation fractionation between Pb and U were reduced even with the prolonged ablation, and thus accuracy of Pb-U age was improved significantly. A chicane-type ion lens system was applied to a quadrupole-based ICPMS instrument. With the chicane ion lens, higher elemental sensitivity (4 times or light mass range and 3 times for mid to heavy mass range) and lower white background ( 238 U- 206 Pb ages for Nancy standard zircon (Nancy 91500), SHRIMP calibration standard zircon (SL13) and Antarctic zircon (PMA7) obtained in this study were 1064 ± 24 Ma, 569 ± 78 Ma and 2438 ± 101 Ma (2-sigma), respectively. Relative age differences from previous reports were 0.2%, 0.4% and 3.2% respectively, demonstrative of high reliability of the method. The REE abundances in zircon samples were calibrated using a NIST 610 glass standard reference material. The resulting REE abundance data for zircons (Nancy 91500 and SL13) show good agreement with those for literature values within the analytical precision of ∼20%. The matrix effect that may occur between the synthetic glass standard and zircon crystals is obviously smaller than the precision and thus negligible for this precision levels. The data presented here demonstrate clearly that the combination of ArF excimer laser an ICPMS equipped with the chicane ion lens has a potential to become a significant tool for zircon geochemistry. (author)

Geophysical evidence for melt in the deep lunar interior and implications for lunar evolution

Science.gov (United States)

Khan, A.; Connolly, J. A. D.; Pommier, A.; Noir, J.

2014-10-01

Analysis of lunar laser ranging and seismic data has yielded evidence that has been interpreted to indicate a molten zone in the lowermost mantle overlying a fluid core. Such a zone provides strong constraints on models of lunar thermal evolution. Here we determine thermochemical and physical structure of the deep Moon by inverting lunar geophysical data (mean mass and moment of inertia, tidal Love number, and electromagnetic sounding data) in combination with phase-equilibrium computations. Specifically, we assess whether a molten layer is required by the geophysical data. The main conclusion drawn from this study is that a region with high dissipation located deep within the Moon is required to explain the geophysical data. This region is located within the mantle where the solidus is crossed at a depth of ˜1200 km (≥1600°C). Inverted compositions for the partially molten layer (150-200 km thick) are enriched in FeO and TiO2 relative to the surrounding mantle. The melt phase is neutrally buoyant at pressures of ˜4.5-4.6 GPa but contains less TiO2 (<15 wt %) than the Ti-rich (˜16 wt %) melts that produced a set of high-density primitive lunar magmas (density of 3.4 g/cm3). Melt densities computed here range from 3.25 to 3.45 g/cm3 bracketing the density of lunar magmas with moderate-to-high TiO2 contents. Our results are consistent with a model of lunar evolution in which the cumulate pile formed from crystallization of the magma ocean as it overturned, trapping heat-producing elements in the lower mantle.

Lunar Impact Flash Locations from NASA's Lunar Impact Monitoring Program

Science.gov (United States)

Moser, D. E.; Suggs, R. M.; Kupferschmidt, L.; Feldman, J.

2015-01-01

Meteoroids are small, natural bodies traveling through space, fragments from comets, asteroids, and impact debris from planets. Unlike the Earth, which has an atmosphere that slows, ablates, and disintegrates most meteoroids before they reach the ground, the Moon has little-to-no atmosphere to prevent meteoroids from impacting the lunar surface. Upon impact, the meteoroid's kinetic energy is partitioned into crater excavation, seismic wave production, and the generation of a debris plume. A flash of light associated with the plume is detectable by instruments on Earth. Following the initial observation of a probable Taurid impact flash on the Moon in November 2005,1 the NASA Meteoroid Environment Office (MEO) began a routine monitoring program to observe the Moon for meteoroid impact flashes in early 2006, resulting in the observation of over 330 impacts to date. The main objective of the MEO is to characterize the meteoroid environment for application to spacecraft engineering and operations. The Lunar Impact Monitoring Program provides information about the meteoroid flux in near-Earth space in a size range-tens of grams to a few kilograms-difficult to measure with statistical significance by other means. A bright impact flash detected by the program in March 2013 brought into focus the importance of determining the impact flash location. Prior to this time, the location was estimated to the nearest half-degree by visually comparing the impact imagery to maps of the Moon. Better accuracy was not needed because meteoroid flux calculations did not require high-accuracy impact locations. But such a bright event was thought to have produced a fresh crater detectable from lunar orbit by the NASA spacecraft Lunar Reconnaissance Orbiter (LRO). The idea of linking the observation of an impact flash with its crater was an appealing one, as it would validate NASA photometric calculations and crater scaling laws developed from hypervelocity gun testing. This idea was

Simulated Lunar Testing of Metabolic Heat Regenerated Temperature Swing Adsorption Technology

Science.gov (United States)

Padilla, Sebastian A.; Bower, Chad; Iacomini, Christie S.; Paul, H.

2011-01-01

Metabolic heat regenerated Temperature Swing Adsorption (MTSA) technology is being developed for thermal and carbon dioxide (CO2) control for a Portable Life Support System (PLSS), as well as water recycling. An Engineering Development Unit (EDU) of the MTSA subassembly was designed and assembled for optimized Martian operations, but also meets system requirements for lunar operations. For lunar operations the MTSA sorption cycle is driven via a vacuum swing between suit ventilation loop pressure and lunar vacuum. The focus of this effort is operations and testing in a simulated lunar environment. This environment was simulated in Paragon s EHF vacuum chamber. The objective of this testing was to evaluate the full cycle performance of the MTSA Subassembly EDU, and to assess CO2 loading and pressure drop of the wash coated aluminum reticulated foam sorbent bed. The lunar testing proved out the feasibility of pure vacuum swing operation, making MTSA a technology that can be tested and used on the Moon prior to going to Mars. Testing demonstrated better than expected CO2 loading on the sorbent and nearly replicates the equilibrium data from the sorbent manufacturer. This had not been achieved in any of the previous sorbent loading tests performed by Paragon. Subsequently, the increased performance of the sorbent bed design indicates future designs will require less mass and volume than the current EDU rendering MTSA as very competitive for Martian PLSS applications.

First oxygen from lunar basalt

Science.gov (United States)

Gibson, M. A.; Knudsen, C. W.; Brueneman, D. J.; Kanamori, H.; Ness, R. O.; Sharp, L. L.; Brekke, D. W.; Allen, C. C.; Morris, R. V.; Keller, L. P.

1993-01-01

The Carbotek/Shimizu process to produce oxygen from lunar soils has been successfully demonstrated on actual lunar samples in laboratory facilities at Carbotek with Shimizu funding and support. Apollo sample 70035 containing approximately 25 percent ilmenite (FeTiO3) was used in seven separate reactions with hydrogen varying temperature and pressure: FeTiO3 + H2 yields Fe + TiO2 + H2O. The experiments gave extremely encouraging results as all ilmenite was reduced in every experiment. The lunar ilmenite was found to be about twice as reactive as terrestrial ilmenite samples. Analytical techniques of the lunar and terrestrial ilmenite experiments performed by NASA Johnson Space Center include iron Mossbauer spectroscopy (FeMS), optical microscopy, SEM, TEM, and XRD. The Energy and Environmental Research Center at the University of North Dakota performed three SEM techniques (point count method, morphology determination, elemental mapping), XRD, and optical microscopy.

Thermodynamics of lunar ilmenite reduction

Science.gov (United States)

Altenberg, B. H.; Franklin, H. A.; Jones, C. H.

1993-01-01

With the prospect of returning to the moon, the development of a lunar occupation would fulfill one of the goals of the Space Exploration Initiative (SEI) of the late 1980's. Processing lunar resources into useful products, such as liquid oxygen for fuel and life support, would be one of many aspects of an active lunar base. ilmenite (FeTiO3) is found on the lunar surface and can be used as a feed stock to produce oxygen. Understanding the various ilmenite-reduction reactions elucidates many processing options. Defining the thermodynamic chemical behavior at equilibrium under various conditions of temperature and pressures can be helpful in specifying optimal operating conditions. Differences between a previous theoretical analysis and experimentally determined results has sparked interest in trying to understand the effect of operating pressure on the hydrogen-reduction-of-ilmenite reaction. Various aspects of this reduction reaction are discussed.

The enigma of lunar magnetism

Science.gov (United States)

Hood, L. L.

1981-01-01

Current understandings of the nature and probable origin of lunar magnetism are surveyed. Results of examinations of returned lunar samples are discussed which reveal the main carrier of the observed natural remanent magnetization to be iron, occasionally alloyed with nickel and cobalt, but do not distinguish between thermoremanent and shock remanent origins, and surface magnetometer data is presented, which indicates small-scale magnetic fields with a wide range of field intensities implying localized, near-surface sources. A detailed examination is presented of orbital magnetometer and charged particle data concerning the geologic nature and origin of magnetic anomaly sources and the directional properties of the magnetization, which exhibit a random distribution except for a depletion in the north-south direction. A lunar magnetization survey with global coverage provided by a polar orbiting satellite is suggested as a means of placing stronger constraints on the origin of lunar crustal magnetization.

Lunar Riometry: Proof-of-Concept Instrument Package

Science.gov (United States)

Lazio, J.; Jones, D. L.; MacDowall, R. J.; Stewart, K.; Giersch, L.; Burns, J. O.; Farrell, W. M.; Kasper, J. C.; O'Dwyer, I.; Hartman, J.

2012-12-01

The lunar exosphere is the exemplar of a plasma near the surface of an airless body. Exposed to both the solar and interstellar radiation fields, the lunar exosphere is mostly ionized, and enduring questions regarding its properties include its density and vertical extent, the extent of contributions from volatile outgassing from the Moon, and its behavior over time, including response to the solar wind and modification by landers. Relative ionospheric measurements (riometry) is based on the simple physical principle that electromagnetic waves cannot propagate through a partially or fully ionized medium below the plasma frequency, and riometers have been deployed on the Earth in numerous remote and hostile environments. A multi-frequency riometer on the lunar surface would be able to monitor, in situ, the vertical extent of the lunar exosphere over time. We describe a concept for a riometer implemented as a secondary science payload on future lunar landers, such as those recommended in the recent Planetary Sciences Decadal Survey report. The instrument concept is simple, consisting of an antenna implemented as a metal deposited on polyimide film and receiver. We illustrate various deployment mechanisms and performance of a prototype in increasing lunar analog conditions. While the prime mission of such a riometer would be probing the lunar exosphere, our concept would also be capable to measuring the properties of dust impactors. The Lunar University Network for Astrophysical Research consortium is funded by the NASA Lunar Science Institute to investigate concepts for astrophysical observatories on the Moon. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA.

Dielectric Strontium Zirconate Sprayed by a Plasma Torch.

Czech Academy of Sciences Publication Activity Database

Ctibor, Pavel; Sedláček, J.; Janata, Marek

2017-01-01

Roč. 10, č. 4 (2017), s. 225-230 ISSN 2008-2134 Institutional support: RVO:61389021 Keywords : Plasma spraying * Electrical properties * Strontium Zirconate * Insulators Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass OBOR OECD: Ceramics www.pccc.icrc.ac.ir/Articles/18/1/18/1010/

Building an Economical and Sustainable Lunar Infrastructure to Enable Lunar Science and Space Commerce

Science.gov (United States)

Zuniga, Allison; Turner, Mark; Rasky, Dan

2017-01-01

A new concept study was initiated to examine the framework needed to gradually develop an economical and sustainable lunar infrastructure using a public private partnerships approach. This approach would establish partnership agreements between NASA and industry teams to develop cis-lunar and surface capabilities for mutual benefit while sharing cost and risk in the development phase and then allowing for transfer of operation of these infrastructure services back to its industry owners in the execution phase. These infrastructure services may include but are not limited to the following: lunar cargo transportation, power stations, energy storage devices, communication relay satellites, local communication towers, and surface mobility operations.

Gamma-rays attenuation of zircons from Cambodia and South Africa at different energies: A new technique for identifying the origin of gemstone

International Nuclear Information System (INIS)

Limkitjaroenporn, P.; Kaewkhao, J.

2014-01-01

In this work, the gamma-rays interaction properties of zircons from Cambodia and South Africa have been studied. The densities of Cambodian and South African’s zircons are 4.6716±0.0040 g/cm 3 and 4.5505±0.0018 g/cm 3 , respectively. The mass attenuation coefficient and the effective atomic number of gemstones were measured with the gamma-ray in energies range 223–662 keV using the Compton scattering technique. The mass attenuation coefficients of both zircons decreased with the increasing of gamma-rays energies. The different mass attenuation coefficients between the two zircons observed at gamma-ray energies below 400 keV are attributed to the differences in the photoelectric interaction. The effective atomic number of zircons was decreased with the increasing of gamma-ray energies and showed totally different values between the Cambodia and South Africa sources. The origins of the two zircons could be successfully identified by the method based on gamma-rays interaction with matter with advantage of being a non-destructive testing. - Highlights: • Gamma-rays interaction of zircons from Cambodia and South Africa studied. • Measured energy is during 223–662 keV. • Different μ m between the two zircons observed at gamma-ray energies below 400 keV. • The origins the two zircons could be successfully identified

The search for Ar in the lunar atmosphere using the Lunar Reconnaissance Orbiter's LAMP instrument.

Science.gov (United States)

Cook, J. C.; Stern, S. A.; Feldman, P. D.; Gladstone, R.; Retherford, K. D.; Greathouse, T. K.; Grava, C.

2014-12-01

The Apollo 17 mass spectrometer, LACE, first measured mass 40 particles in the lunar atmosphere, and over a nine-month period, detected variations correlated with the lunar day (Hoffman et al., 1973, LPSC, 4, 2865). LACE detected a high particle density at dusk (0.6-1.0x104 cm-3), decreasing through the lunar night to a few hundred cm-3, then increasing rapidly before dawn to levels 2-4 times greater than at dusk. No daytime measurements were made due to instrument saturation. Given the LACE measurements' periodic nature, and the Ar abundance in lunar regolith samples (Kaiser, 1972, EPSL, 13, 387), it was concluded that mass 40 was likely due to Ar. Benna et al. (2014, LPSC, 45, 1535) recently reported that the Neutral Mass Spectrometer (NMS) aboard LADEE also detected Ar (mass 40) with similar diurnal profiles. We report on UV spectra of the lunar atmosphere as obtained by the Lunar Reconnaissance Orbiter (LRO). Aboard LRO is the UV-spectrograph, LAMP (Lyman Alpha Mapping Project), spanning the spectral range 575 to 1965 Å. LAMP is typically oriented toward the surface and has been mapping the Moon since September 2009. LAMP also observes the tenuous lunar atmosphere when the surface is in darkness, but the atmospheric column below LRO is illuminated. We have previously used nadir oriented twilight observations to examine the sparse lunar atmosphere (Feldman et al., 2012, Icarus, 221, 854; Cook et al., 2013, Icarus, 225, 681; Stern et al., 2013, Icarus, 226, 1210; Cook & Stern 2014, Icarus, 236, 48). In Cook et al., 2013, we reported an upper limit for Ar of 2.3x104 cm-3. Since then, we have collected additional data and refined our search method by focusing on the regions (near equator) and local times (dawn and dusk) where Ar has been reported previously. We have carefully considered effective area calibration and g-factor accuracies and find these to be unlikely explanations for the order of magnitude differences. We will report new results, which provide much

Tests of the lunar hypothesis

Science.gov (United States)

Taylor, S. R.

1984-01-01

The concept that the Moon was fissioned from the Earth after core separation is the most readily testable hypothesis of lunar origin, since direct comparisons of lunar and terrestrial compositions can be made. Differences found in such comparisons introduce so many ad hoc adjustments to the fission hypothesis that it becomes untestable. Further constraints may be obtained from attempting to date the volatile-refractory element fractionation. The combination of chemical and isotopic problems suggests that the fission hypothesis is no longer viable, and separate terrestrial and lunar accretion from a population of fractionated precursor planetesimals provides a more reasonable explanation.

Development of a lunar infrastructure

Science.gov (United States)

Burke, J. D.

1988-01-01

The problem of building an infrastructure on the moon is discussed, assuming that earth-to-moon and moon-to-earth transport will be available. The sequence of events which would occur in the process of building an infrastructure is examined. The human needs which must be met on a lunar base are discussed, including minimal life support, quality of life, and growth stages. The technology available to meet these needs is reviewed and further research in fields related to a lunar base, such as the study of the moon's polar regions and the limits of lunar agriculture, is recommended.

A preliminary geochemical study of zircons and monazites from ...

Indian Academy of Sciences (India)

R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

equation of Watson and Harrison (1983) predicts that zircon with Zr-contents ... tion equation of Montel (1993) predicts that the .... and geochemistry of the basalts of Gujarat state (western ... solution kinetics: implications for the thorium and light.

Geochronology and Geochemistry of Zircons from the IODP Site U1437 in the Rear of the Izu-Bonin Volcanic Arc

Science.gov (United States)

Andrews, G. D.; Schmitt, A. K.; Busby, C. J.; Brown, S. R.

2015-12-01

Zircons recovered from International Ocean Discovery Program Expedition 350 Site U1437 (31°47.390'N, 139°01.580'E) in the Izu-Bonin arc were analyzed by SIMS to constrain their age (U/Pb geochronology) and geochemistry (trace elements, δ18O); LA-ICP-MS ɛHf analyses are pending. Seven intervals were dated successfully: six tuffs and lapilli-tuffs between 680.99 and 1722.46 m below sea floor (mbsf) and a single peperitic rhyolitic intrusion at 1388.86 - 1390.07 mbsf. Thirty-two intervals which underwent mineral separation lacked zircon, or yielded zircon much older than age expectations for U1437. Geochronology results from separated zircons confirm and extend the shipboard age model to 1360.77 mbsf where Late Miocene (Tortonian) submarine volcanic rocks (11.3 ±0.7 Ma; n = 17) were sampled. In-situ measurement of zircons associated with magnetite crystals in the rhyolite intrusion yield an age of 13.6 ±1.7 Ma (n = 9). Zircon U contents are low (typically <300 ppm), with trace element ratios characteristic of oceanic lithosphere and near-mantle δ18O values (4-6 ‰). Individual Miocene zircon crystals are difficult to distinguish by age alone from those in the drilling mud (sepiolite) used during Expedition 350; the sepiolite is quarried by IMV Nevada in the Amargosa Valley. Our analysis of thirty-three zircons from the sepiolite finds that they have a broad and varied age distribution (2 - 2033 Ma) with a prominent peak at 12-14 Ma, bimodal δ18O values (peaks at 5-5.5 and 6.5-7.5 ‰), and dominantly continental trace element signatures. Three zircons from U1437 are tentatively identified as sepiolite-derived, but a single Eocene grain (51.7 ±2.4 Ma) recovered from 1722.46 mbsf has an age unlike those in the sepiolite, and potentially is genuinely xenocrystic. The majority of U1437 zircons thus crystallized from evolved melts lacking continental characteristics, although thermal and compositional conditions conducive for zircon crystallization appear to have

New Age for Lunar Exploration

Science.gov (United States)

Taylor, G. J.; Martel, L. M. V.

2018-04-01

Lunar-focused research and plans to return to the lunar surface for science and exploration have reemerged since the Space Policy Directive-1 of December 11, 2017 amended the National Space Policy to include the following, "Lead an innovative and sustainable program of exploration with commercial and international partners to enable human expansion across the solar system and to bring back to Earth new knowledge and opportunities. Beginning with missions beyond low-Earth orbit, the United States will lead the return of humans to the Moon for long-term exploration and utilization, followed by human missions to Mars and other destinations." In response to this revision, NASA proposes a Lunar Exploration and Discovery Program in the U.S. fiscal year 2019 Budget Request. It supports NASA's interests in commercial and international partnerships in Low-Earth Orbit (LEO), long-term exploration in Cislunar space beyond LEO, and research and exploration conducted on the Moon to inform future crewed missions, even to destinations beyond the Moon. (Cislunar refers to the volume of space between LEO and the Moon's orbital distance.) The lunar campaign strengthens the integration of human and robotic activities on the lunar surface with NASA's science, technology, and exploration goals.

The lunar tide in sporadic E

Directory of Open Access Journals (Sweden)

R. J. Stening

1999-10-01

Full Text Available It seems that the wind shear theory is accepted for the explanation of sporadic E at mid and low latitudes. Some examples from Arecibo are displayed to show this. The effect of lunar tides should then modify the wind-shear theory in a manner that yields the observed features of the lunar tide in the critical frequency foEs and the height h'Es of the sporadic E. This is shown to imply that the phase of the lunar tide in h'Es should be the same as the phase of the lunar tide in the eastward wind and that the phase of the lunar tide in foEs is three hours later. Hourly values of foEs, f bEs (the blanketing critical frequency and h'Es from several observatories are analysed for the lunar semidiurnal tide. It is found that the phase of the tide in foEs is often about 3 hours later than for h'Es in agreement with the theory. Seasonal variations in the tide are also examined with the statistically most significant results (largest amplitudes usually occurring in summer. After reviewing the many difficulties associated with determining the lunar tide in Es, both experimentally and theoretically, the analysed phase results are compared with what might be expected from Hagan's global scale wave model. Agreement is only fair (a success rate of 69% among the cases examined but probably as good as might be expected.Key words. Ionosphere (ionosphere – atmosphere interactions – ionospheric irregularities, Meteorology and atmosphere dynamics (waves and tides

A novel lunar bed rest analogue.

Science.gov (United States)

Cavanagh, Peter R; Rice, Andrea J; Licata, Angelo A; Kuklis, Matthew M; Novotny, Sara C; Genc, Kerim O; Englehaupt, Ricki K; Hanson, Andrea M

2013-11-01

Humans will eventually return to the Moon and thus there is a need for a ground-based analogue to enable the study of physiological adaptations to lunar gravity. An important unanswered question is whether or not living on the lunar surface will provide adequate loading of the musculoskeletal system to prevent or attenuate the bone loss that is seen in microgravity. Previous simulations have involved tilting subjects to an approximately 9.5 degrees angle to achieve a lunar gravity component parallel to the long-axis of the body. However, subjects in these earlier simulations were not weight-bearing, and thus these protocols did not provide an analogue for load on the musculoskeletal system. We present a novel analogue which includes the capability to simulate standing and sitting in a lunar loading environment. A bed oriented at a 9.5 degrees angle was mounted on six linear bearings and was free to travel with one degree of freedom along rails. This allowed approximately 1/6 body weight loading of the feet during standing. "Lunar" sitting was also successfully simulated. A feasibility study demonstrated that the analogue was tolerated by subjects for 6 d of continuous bed rest and that the reaction forces at the feet during periods of standing were a reasonable simulation of lunar standing. During the 6 d, mean change in the volume of the quadriceps muscles was -1.6% +/- 1.7%. The proposed analogue would appear to be an acceptable simulation of lunar gravity and deserves further exploration in studies of longer duration.

Zircon's Archean of the Ural

International Nuclear Information System (INIS)

Krasnobaev, A.A.; Cherednichenko, N.V.

2005-01-01

The age of zircons from metamorphic rocks of the Taratashsky complex located on the Western slope of the South Urals was determined by the methods of U-Pb isotope dating. The age values obtained suggest a two-stage model of the complex evolution at early stages of its existence. The age of 2913±133 mln. years identifies the age of granulite metamorphism, while the age 2127±65 mln. years indicates the period of the most intensive transformations of the rocks within the complex, which were accompanied by occurrence of high-temperature diaphthorites [ru

Soft mode of lead zirconate

International Nuclear Information System (INIS)

Pan'ko, G.F.; Prisedskij, V.V.; Klimov, V.V.

1983-01-01

Anisotropic diffusional scattering of electrons on PbZrO 3 crystal in the temperature range of phase transition has been recorded. As a result of its analysis it has been established that in lead zirconate the rotational vibrational mode G 25 plays the role of soft mode. The experiment is carried out using PbZrO 3 monocrystals in translucent electron microscope EhM-200, operating in the regime of microdiffraction at accelerating voltage of 150 kV and beam current 50 μA; sample preparation is realized using the method of shearing and fragmentation

Composition of zircons from the Cornubian Batholith of SW England and comparison with zircons from other European Variscan rare-metal granites

Czech Academy of Sciences Publication Activity Database

Breiter, Karel; Müller, A.; Shail, R.; Simons, B.

2016-01-01

Roč. 80, č. 7 (2016), s. 1-17 ISSN 0026-461X R&D Projects: GA ČR GA14-13600S Institutional support: RVO:67985831 Keywords : zircon * chemical composition * Cornwall * rare-metal granite Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.285, year: 2016

Evaluating the High School Lunar Research Projects Program

Science.gov (United States)

Shaner, A. J.; Shupla, C.; Shipp, S.; Allen, J.; Kring, D. A.

2013-01-01

The Center for Lunar Science and Exploration (CLSE), a collaboration between the Lunar and Planetary Institute and NASA s Johnson Space Center, is one of seven member teams of the NASA Lunar Science Institute (NLSI). In addition to research and exploration activities, the CLSE team is deeply invested in education and outreach. In support of NASA s and NLSI s objective to train the next generation of scientists, CLSE s High School Lunar Research Projects program is a conduit through which high school students can actively participate in lunar science and learn about pathways into scientific careers. The objectives of the program are to enhance 1) student views of the nature of science; 2) student attitudes toward science and science careers; and 3) student knowledge of lunar science. In its first three years, approximately 168 students and 28 teachers from across the United States have participated in the program. Before beginning their research, students undertake Moon 101, a guided-inquiry activity designed to familiarize them with lunar science and exploration. Following Moon 101, and guided by a lunar scientist mentor, teams choose a research topic, ask their own research question, and design their own research approach to direct their investigation. At the conclusion of their research, teams present their results to a panel of lunar scientists. This panel selects four posters to be presented at the annual Lunar Science Forum held at NASA Ames. The top scoring team travels to the forum to present their research in person.

Modeling Respiratory Toxicity of Authentic Lunar Dust

Science.gov (United States)

Santana, Patricia A.; James, John T.; Lam, Chiu-Wing

2010-01-01

The lunar expeditions of the Apollo operations from the 60 s and early 70 s have generated awareness about lunar dust exposures and their implication towards future lunar explorations. Critical analyses on the reports from the Apollo crew members suggest that lunar dust is a mild respiratory and ocular irritant. Currently, NASA s space toxicology group is functioning with the Lunar Airborne Dust Toxicity Assessment Group (LADTAG) and the National Institute for Occupational Safety and Health (NIOSH) to investigate and examine toxic effects to the respiratory system of rats in order to establish permissible exposure levels (PELs) for human exposure to lunar dust. In collaboration with the space toxicology group, LADTAG and NIOSH the goal of the present research is to analyze dose-response curves from rat exposures seven and twenty-eight days after intrapharyngeal instillations, and model the response using BenchMark Dose Software (BMDS) from the Environmental Protection Agency (EPA). Via this analysis, the relative toxicities of three types of Apollo 14 lunar dust samples and two control dust samples, titanium dioxide (TiO2) and quartz will be determined. This will be executed for several toxicity endpoints such as cell counts and biochemical markers in bronchoaveolar lavage fluid (BALF) harvested from the rats.

Sample-scale zircon geochemical and geochronological heterogeneities as indicators of residual liquid infiltration events in the incrementally assembled Caleu Pluton, Central Chile

Science.gov (United States)

Molina, P. G.; Parada, M. A.; Gutiérrez, F. J.; Ma, C.; Li, J.; Liu, Y.

2013-12-01

The Upper Cretaceous metaluminous Caleu Pluton is emplaced at a depth equivalent of 2kbar and consists of four lithological zones: the Gabbro-Dioritic Zone (GDZ), the Quartz-Monzodioritic Zone (QMDZ), the Granodioritic Zone (GZ) and the Monzogranitic Zone (MGZ). The zones would have been fed from a deeper magma reservoir emplaced at a 4 kbar. U238/Pb206 LA-ICP-MS geochronology of zircon grains of the four lithological zones (82 analyzed spots, 4 samples) indicates a maximum zircon crystallization range of ca. 106-91 Ma for the pluton as a whole. The U-Pb zircon age distribution of the four samples shows three inflection points at about 101, 99 and 96 Ma, separating four zircon crystallization events with the following weighted average ages and 2σ confidence intervals: 103.×1.6 Ma (n=4), 100.3×0.68 Ma (n=14), 97.49×0.49 Ma (n=25) and 94.66×0.44 Ma (n=30). The GDZ sample records the first three events, the GZ and QMDZ samples record the last three events while the MGZ only have zircons formed during the last two events. It is interesting to note that the youngest event of zircon formation coincide with the Ar/Ar cooling ages (95-93 Ma) previously obtained in hornblende, biotite and plagioclase of the four lithological zones, as a consequence of a rapid pluton exhumation. Temperatures of zircon crystallization (Ti-in-Zrn) obtained in each sample are variable and roughly lower than the zircon saturation temperatures. Most of the Ti-in-Zrn temperatures indicate late-stage crystallization conditions, consistent with the calculated melt composition from which zircons would have crystallized and the observed coexistence of zircons with quartz-orthoclase symplectites, hornblende and interstitial anhedral biotite. There are variable and overlapped total incompatible element concentrations in zircons of the four lithological zones regardless its age and Ti-in-Zrn temperatures, indicating that the melts from which zircon crystallized at different moments, were equivalent

CisLunar Habitat Internal Architecture Design Criteria

Science.gov (United States)

Jones, R.; Kennedy, K.; Howard, R.; Whitmore, M.; Martin, C.; Garate, J.

2017-01-01

BACKGROUND: In preparation for human exploration to Mars, there is a need to define the development and test program that will validate deep space operations and systems. In that context, a Proving Grounds CisLunar habitat spacecraft is being defined as the next step towards this goal. This spacecraft will operate differently from the ISS or other spacecraft in human history. The performance envelope of this spacecraft (mass, volume, power, specifications, etc.) is being defined by the Future Capabilities Study Team. This team has recognized the need for a human-centered approach for the internal architecture of this spacecraft and has commissioned a CisLunar Phase-1 Habitat Internal Architecture Study Team to develop a NASA reference configuration, providing the Agency with a "smart buyer" approach for future acquisition. THE CISLUNAR HABITAT INTERNAL ARCHITECTURE STUDY: Overall, the CisLunar Habitat Internal Architecture study will address the most significant questions and risks in the current CisLunar architecture, habitation, and operations concept development. This effort is achieved through definition of design criteria, evaluation criteria and process, design of the CisLunar Habitat Phase-1 internal architecture, and the development and fabrication of internal architecture concepts combined with rigorous and methodical Human-in-the-Loop (HITL) evaluations and testing of the conceptual innovations in a controlled test environment. The vision of the CisLunar Habitat Internal Architecture Study is to design, build, and test a CisLunar Phase-1 Habitat Internal Architecture that will be used for habitation (e.g. habitability and human factors) evaluations. The evaluations will mature CisLunar habitat evaluation tools, guidelines, and standards, and will interface with other projects such as the Advanced Exploration Systems (AES) Program integrated Power, Avionics, Software (iPAS), and Logistics for integrated human-in-the-loop testing. The mission of the CisLunar

Acoustic response of piezoelectric lead-zirconate-titanate to a 400MeV/n xenon beam

CERN Document Server

Miyachi, T; Ito, H

2003-01-01

Characteristics of lead-zirconate-titanate (PZT) elements were studied by directly irradiating them with a 400 MeV/n Xe beam. The elements were sensitive to 10 sup 4 Xe ions and their output amplitudes were proportional to the beam intensity. An ensemble of those output amplitudes displayed a Bragg-curve-like response towards the range of 400 MeV/n Xe ion. We discuss the potential of PZT elements as a radiation detector and their application to high-intensity and high-energy detectors. (author)

APOLLO 10 ASTRONAUT ENTERS LUNAR MODULE SIMULATOR

Science.gov (United States)

1969-01-01

Apollo 10 lunar module pilot Eugene A. Cernan prepares to enter the lunar module simulator at the Flight Crew Training Building at the NASA Spaceport. Cernan, Apollo 10 commander Thomas P. Stafford and John W. Young, command module pilot, are to be launched May 18 on the Apollo 10 mission, a dress rehearsal for a lunar landing later this summer. Cernan and Stafford are to detach the lunar module and drop to within 10 miles of the moon's surface before rejoining Young in the command/service module. Looking on as Cernan puts on his soft helmet is Snoopy, the lovable cartoon mutt whose name will be the lunar module code name during the Apollo 10 flight. The command/service module is to bear the code name Charlie Brown.

Real-Time Science Operations to Support a Lunar Polar Volatiles Rover Mission

Science.gov (United States)

Heldmann, Jennifer L.; Colaprete, Anthony; Elphic, Richard C.; Mattes, Greg; Ennico, Kimberly; Fritzler, Erin; Marinova, Margarita M.; McMurray, Robert; Morse, Stephanie; Roush, Ted L.;

U-Pb ages in meta-rhyolite zircon from Arai Group and associated granites

International Nuclear Information System (INIS)

Pimentel, M.M.; Fuck, R.A.

1991-01-01

Geochronology results by V-Pb method in zircon of granite rocks from staniferous province of Goias and rhyolite Arai groups are revealed. Two distinct episode of acid magmatism in Paleo-and Meso proterozoic are presented. V-Pb data in zircon from Sucuri and Soledade granites of the province from Parana River with ages of higher intercepted are also defined. This ages are consider mistakes, similar the V-Pb age of a rhyolite from Arai group. (author)

U-Pb Detrital Zircon Ages from Sarawak: Changes in Provenance Reflecting the Tectonic Evolution of Southeast Asia

Science.gov (United States)

Breitfeld, H. T.; Galin, T.; Hall, R.

2014-12-01

Sarawak is located on the northern edge of Sundaland in NW Borneo. Five sedimentary basins are distinguished with ages from Triassic to Cenozoic. New light mineral, heavy mineral and U-Pb detrital zircon ages show differences in provenance reflecting the tectonic evolution of the region. The oldest clastic sediments are Triassic of the Sadong-Kuching Basin and were sourced by a Carnian to Norian volcanic arc and erosion of Cathaysian rocks containing zircons of Paleoproterozoic age. Sandstones of the Upper Jurassic to Cretaceous Bau-Pedawan Basin have distinctive zircon populations indicating a major change of tectonic setting, including initiation of subduction below present-day West Sarawak in the Late Jurassic. A wide range of inherited zircon ages indicates various Cathaysian fragments as major source areas and the arrival of the SW Borneo Block following subduction beneath the Schwaner Mountains in the early Late Cretaceous. After collision of the SW Borneo Block and the microcontinental fragments with Sundaland in the early Late Cretaceous, deep marine sedimentation (Pedawan Formation) ceased, and there was uplift forming the regional Pedawan-Kayan unconformity. Two episodes of extension were responsible for basin development on land from the latest Cretaceous onwards, probably in a strike-slip setting. The first episode formed the Kayan Basin in the Latest Cretaceous (Maastrichtian) to Early Paleocene, and the second formed the Ketungau Basin and the Penrissen Sandstone in the Middle to Late Eocene. Zircons indicate nearby volcanic activity throughout the Early Cenozoic in NW Borneo. Inherited zircon ages indicate an alternation between Borneo and Tin Belt source rocks. A large deep marine basin, the Rajang Basin, formed north of the Lupar Line fault. Zircons from sediments of the Rajang Basin indicate they are of similar age and provenance as the contemporaneous terrestrial sediments to the south suggesting a narrow steep continental Sundaland margin at the

Strategy for the International Lunar Decade

Science.gov (United States)

Beldavs, V.; Dunlop, D.; Foing, B.

2015-10-01

related concerns. The Moon Treaty (1979) will be reviewed for its applicability to the development of the international regime that will be required to govern mining, industrial development and commercial activities on the Moon. ILD has already been a significant topic in several international conferences.Through this and many other conferences to follow the initial organizers expect that key organizations will see a role for their activities within the ILD process, endorse it and start to shape implementation plans. This report will focus on overall strategies for the ILD process to fully engage multiple countries and organizations building towards a shared vision through a diversity of scientific, technical and cultural perspectives. Public outreach and involvement of the public, particularly youth and schools will be an important component of the overall strategy. The activities of the International Lunar Decade Working Group can be followed at https://ildwg.wordpress.com .

Real-Time Salmonella Detection Using Lead Zirconate Titanate-Titanium Microcantilevers

National Research Council Canada - National Science Library

McGovern, John-Paul; Shih, Wan Y; Shih, Wei-Heng; Sergi, Mauro; Chaiken, Irwin

2005-01-01

.... We have developed and investigated the use of a lead zirconate titanate - titanium (PZT-Ti) microcantilever for in situ detection of the common food- and water-born pathogen, Salmonella typhimurium...

Proterozoic to Mesozoic evolution of North-West Africa and Peri-Gondwana microplates: Detrital zircon ages from Morocco and Canada

Science.gov (United States)

Marzoli, Andrea; Davies, Joshua H. F. L.; Youbi, Nasrrddine; Merle, Renaud; Dal Corso, Jacopo; Dunkley, Daniel J.; Fioretti, Anna Maria; Bellieni, Giuliano; Medina, Fida; Wotzlaw, Jörn-Frederik; McHone, Greg; Font, Eric; Bensalah, Mohamed Khalil

2017-05-01

The complex history of assemblage and disruption of continental plates surrounding the Atlantic Ocean is in part recorded by the distribution of detrital zircon ages entrained in continental sedimentary strata from Morocco (Central High Atlas and Argana basins) and Canada (Grand Manan Island, New Brunswick). Here we investigate detrital zircon from the latest Triassic (ca. 202 Ma) sedimentary strata directly underlying lava flows of the Central Atlantic magmatic province or interlayered within them. SHRIMP (Sensitive High-Resolution Ion MicroProbe) and LA-ICP-MS (Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry) U-Pb ages for zircon range from Paleozoic to Archean with a dominant Neoproterozoic peak, and significant amounts of ca. 2 Ga zircon. These ages suggest a prevailing West African (Gondwanan) provenance at all sampling sites. Notably, the Paleoproterozoic zircon population is particularly abundant in central Morocco, north of the High Atlas chain, suggesting the presence of Eburnean-aged rocks in this part of the country, which is consistent with recent geochronologic data from outcropping rocks. Minor amounts of late Mesoproterozoic and early Neoproterozoic zircon ages (ca. 1.1-0.9 Ga) in Moroccan samples are more difficult to interpret. A provenance from Avalonia or Amazonia, as proposed by previous studies is not supported by the age distributions observed here. An involvement of more distal source regions, possibly located in north-eastern Africa (Arabian Nubian Shield) would instead be possible. Paleozoic zircon ages are abundant in the Canadian sample, pointing to a significant contribution from Hercynian aged source rocks. Such a signal is nearly absent in the Moroccan samples, suggesting that zircon-bearing Hercynian granitic rocks of the Moroccan Meseta block were not yet outcropping at ca. 200 Ma. The only Moroccan samples that yield Paleozoic zircon ages are those interlayered within the CAMP lavas, suggesting an increased dismantling

U-Pb systematics of zircon and titanite from the Gardnos impact structure, Norway: Evidence for impact at 546 Ma?

Science.gov (United States)

Kalleson, E.; Corfu, F.; Dypvik, H.

2009-05-01

Zircon and titanite were investigated in impactites of the Gardnos structure, a crater formed in Sveconorwegian (ca. 1 Ga) crust, which was then overridden in the Devonian by Caledonian nappes. Observed deformation features in zircons are granular texture, planar microstructures, and likely the incorporation of organic carbon during impact causing black staining of the zircon grains. The grains were studied by scanning electron microscopy (SEM) and cathode luminescence (CL) and dated by U-Pb isotope dilution - thermo-ionization mass spectrometry (ID-TIMS). Zircon grains without impact related features have U-Pb data showing moderate discordance (5-13%) and indicating formation ages mostly in the range of 1600-1000 Ma, except detrital zircon ages as old as >2481 Ma, reflecting the diversity of target rocks in the area. Titanite with concordant ages of 995-999 Ma dates metamorphism during final juxtaposition of the Telemarkia on the Idefjorden terrane to the east. Zircon grains with demonstrated or presumed shock features yield highly discordant (14-40%) U-Pb data, with a majority of them plotting along an array with a lower intercept of about 340 Ma reflecting the influence of the Caledonian orogeny and recent Pb-loss. One zircon grain was totally reset at 379 Ma during late Caledonian metamorphism, which also caused local growth of new titanite. A specific group of zircon grains yields data with relatively high discordance for moderate U contents, and five of these analyses, including that of a grain with proven granular or aggregate texture, fit a discordia line with an upper intercept of 546 ± 5 Ma. These features are interpreted as indicating zircon break-down to an amorphous state during impact, with subsequent recrystallization into microcrystalline aggregates causing extensive to complete Pb loss. We further suggest that their crystallinity prevented Pb loss during the Caledonian orogeny, while the small subgrain size and increasing metamictisation allowed

Provenance of sediments from Sumatra, Indonesia - Insights from detrital U-Pb zircon geochronology, heavy mineral analyses and Raman spectroscopy

Science.gov (United States)

Liebermann, C.; Hall, R.; Gough, A.

2017-12-01

The island of Sumatra is situated at the southwestern margin of the Indonesian archipelago. Although it is the sixth largest island in the world, the geology of the Sumatra sedimentary basins and their underlying basement is relatively poorly understood in terms of their provenance. This work is a multi-proxy provenance study utilizing U-Pb detrital zircon dating by LA-ICP-MS combined with optical and Raman spectroscopy-based heavy mineral analysis. It will help to unravel the stratigraphy of Sumatra, contribute to paleogeographic reconstruction of western SE Asia, and aid a wider understanding of Sumatran petroleum plays. Thin section analyses, heavy mineral assemblages, and >3500 concordant U-Pb zircon ages, from samples acquired during two fieldwork seasons indicate a mixed provenance for Cenozoic sedimentary formations, including both local igneous sources and mature basement rocks. Characteristic Precambrian zircon age spectra are found in all analysed Cenozoic sedimentary strata. These can be correlated with zircon age populations found in Sumatran basement rocks; Neoproterozoic and Mesoproterozoic age groups are dominant (c. 500-600 Ma, c. 850-1000 Ma, c. 1050-1200 Ma). Paleoproterozoic to Archaean zircons occur as minor populations. The Phanerozoic age spectra of the Cenozoic formations are characterised by distinct Carboniferous, Permo-Triassic, and Jurassic-Cretaceous zircon populations. Permo-Triassic zircons are interpreted to come from granitoids in the Malay peninsula or Sumatra itself. Eocene to Lower Miocene strata are characterised by ultrastable heavy minerals such as zircon, tourmaline, and rutile, which together with garnet, suggest the principal sources were igneous and metamorphic basement rocks. Cenozoic zircons appear only from the Middle Miocene onwards. This change is interpreted to indicate a new contribution from a local volcanic arc, and is supported by the occurrence of unstable heavy minerals such as apatite and clinopyroxene, and the

Annealing of natural metamict zircons. I low degree of radiation damage

CERN Document Server

Colombo, M

1998-01-01

In-situ time dependent high temperature X-ray powder diffraction was used to investigate the ordering process occurring during annealing of natural zircons with a low degree of radiation damage. It was possible to distinguish two stages of this process. Firstly, the diffusion of defects induced by alpha-particles, this stage contributes only to a certain degree of relaxation in the unit cell. In the second stage there is some degree of recrystallization. A hkl-dependence in the variation of the integrated intensity is observed and the increase in the volume of crystalline zircon is therefore related to a process of migration of dislocations.

Detrital zircon U-Pb geochronology of Cambrian to Triassic miogeoclinal and eugeoclinal strata of Sonora, Mexico

Science.gov (United States)

Gehrels, G.E.; Stewart, John H.

1998-01-01

One hundred and eighty two individual detrital zircon grains from Cambrian through Permian miogeoclinal strata, Ordovician eugeoclinal rocks, and Triassic post-orogenic sediments in northwestern Sonora have been analyzed. During Cambrian, Devonian, Permian, and Triassic time, most zircons accumulating along this part of the Cordilleran margin were shed from 1.40-1.45 and 1.62-1.78 Ga igneous rocks that are widespread in the southwestern United States and northwestern Mexico. Zircons with ages of approximately 1.11 Ga are common in Cambrian strata and were apparently shed from granite bodies near the sample site. The sources of 225-280 Ma zircons in our Triassic sample are more problematic, as few igneous rocks of these ages are recognized in northwestern Mexico. Such sources may be present but unrecognized, or the grains could have been derived from igneous rocks of the appropriate ages to the northwest in the Mojave Desert region, to the east in Chihuahua and Coahuila, or to the south in accreted(?) arc-type terranes. Because the zircon grains in our Cambrian and Devonian to Triassic samples could have accumulated in proximity to basement rocks near their present position or in the Death Valley region of southern California, our data do not support or refute the existence of the Mojave-Sonora megashear. Ordovician strata of both miogeoclinal and eugeoclinal affinity are dominated by >1.77 Ga detrital zircons, which are considerably older than most basement rocks in the region. Zircon grains in the miogeoclinal sample were apparently derived from the Peace River arch area of northwestern Canada and transported southward by longshore currents. The eugeoclinal grains may also have come from the Peace River arch region, with southward transport by either sedimentary or tectonic processes, or they may have been shed from off-shelf slivers of continents (perhaps Antarctica?) removed from the Cordilleran margin during Neoproterozoic rifting. It is also possible that the

Spinel-rich lithologies in the lunar highland crust: Linking lunar samples, crystallization experiments and remote sensing

Science.gov (United States)

Gross, J.; Treiman, A. H.

2012-12-01

The discovery of areas rich in (Mg,Fe)-Al spinel on the rims and central peaks of lunar impact basins (by the M3 mapping spectrometer on Chandrayaan-1) has revived the old puzzle of the origin of lunar spinel. (Mg,Fe)-Al spinel is rare but widespread in lunar highlands rocks, and thus might be an important component of the lunar crust [1-3]. However, the origin of this spinel is not clear. Lunar (Mg,Fe)-Al spinel could have formed (1) during 'normal' basalt petrogenesis at high pressure; (2) during low-pressure crystallization of melts rich in olivine and plagioclase components, e.g. impact-melted lunar troctolite; or (3) formed at low pressure during assimilation of anorthosite into picritic magma; thus, lunar spinel-rich areas represent old (pre-impact) intrusions of magma. In the absence of spinel-rich samples from the Moon, however, these ideas have been highly speculative. Here we describe a rock fragment from lunar meteorite ALHA 81005 that we recently reported [4] that not only contains spinel, but is the first spinel-rich lunar sample described. This fragment contains ~30% (Mg,Fe)Al spinel and is so fine grained that it reasonably could represent a larger rock body. However, the fragment is so rich in spinel that it could not have formed by melting a peridotitic mantle or a basaltic lunar crust. The clast's small grain size and its apparent disequilibrium between spinel and pyroxene suggest fairly rapid crystallization at low pressure. It could have formed as a spinel cumulate from an impact melt of troctolitic composition; or from a picritic magma that assimilated crustal anorthosite on its margins. The latter mechanism is preferred because it explains the petrographic and chemical features of our clast, and is consistent with the regional setting of the Moscoviense spinel deposit [4]. To better understand the origin and formation history(s) of spinel-rich rocks, we also performed liquidus/crystallization experiments at low-pressure as analogues for impact

Sound velocity and compressibility for lunar rocks 17 and 46 and for glass spheres from the lunar soil.

Science.gov (United States)

Schreiber, E; Anderson, O L; Sogat, N; Warren, N; Scholz, C

1970-01-30

Four experiments on lunar materials are reported: (i) resonance on glass spheres from the soil; (ii) compressibility of rock 10017; (iii) sound velocities of rocks 10046 and 10017; (iv) sound velocity of the lunar fines. The data overlap and are mutually consistent. The glass beads and rock 10017 have mechanical properties which correspond to terrestrial materials. Results of (iv) are consistent with low seismic travel times in the lunar maria. Results of analysis of the microbreccia (10046) agreed with the soil during the first pressure cycle, but after overpressure the rock changed, and it then resembled rock 10017. Three models of the lunar surface were constructed giving density and velocity profiles.

Lunar Radio Telescopes: A Staged Approach for Lunar Science, Heliophysics, Astrobiology, Cosmology, and Exploration

Science.gov (United States)

Lazio, Joseph; Bowman, Judd D.; Burns, Jack O.; Farrell, W. M.; Jones, D. L.; Kasper, J. C.; MacDowall, R. J.; Stewart, K. P.; Weiler, K.

2012-01-01

Observations with radio telescopes address key problems in cosmology, astrobiology, heliophysics, and planetary science including the first light in the Universe (Cosmic Dawn), magnetic fields of extrasolar planets, particle acceleration mechanisms, and the lunar ionosphere. The Moon is a unique science platform because it allows access to radio frequencies that do not penetrate the Earth's ionosphere and because its far side is shielded from intense terrestrial emissions. The instrument packages and infrastructure needed for radio telescopes can be transported and deployed as part of Exploration activities, and the resulting science measurements may inform Exploration (e.g., measurements of lunar surface charging). An illustrative roadmap for the staged deployment of lunar radio telescopes

Structural Analysis of Lunar Subsurface with Chang'E 3 Lunar Penetrating Radar

Science.gov (United States)

Xu, Yi; Lai, Jialong; Tang, Zesheng

2015-04-01

Geological structure of the subsurface of the Moon provides valuable information for our understanding of lunar evolution. Recently, Chang'E 3 has utilized lunar penetrating radar (LPR), which is equipped on the lunar rover named as Yutu, to detect the lunar geological structure in Northern Imbrium (44.1260N, 19.5014W) for the first time. As an in-situ detector, Chang'E 3 LPR has higher horizontal and vertical resolution and less clutter impact compared to spaceborne radars such as Chandrayaan-1 and Kaguya. In this work, we analyze the LPR data at 500 MHz transmission frequency to obtain the shallow subsurface structure of the landing area of Chang'E 3 in Mare Imbrium. First, filter method and amplitude recover algorithms are introduced for data processing to alleviate the adverse effects of environment and system noises and compensate the amplitude losses during signal propagation. Next, based on the processed LPR data, we present the methods to determine the interfaces between layers. A three-layered structure of the shallow surface of the Moon has been observed. The corresponding real part of relative dielectric constant is inverted with deconvolution method. The average dielectric constants of the surface, second and third layer is 2.8, 3.2 and 3.6, respectively. The phenomenon that the average dielectric constant increases with the depth is consistent with prior art. With the obtained dielectric constants, the thickness of each layer can be calculated. One possible geological picture of the observed three-layered structure is presented as follows. The top layer is lunar regolith with its thickness ranging from 0.59 m to 0.9 m. The second layer is the ejecta blanket of the nearby impact crater, and the corresponding thickness is between 3.6m to 3.9m, which is in good agreement with the model of ejecta blanket thickness (height) as a function of distance from the crater center proposed by Melosh in 1989. The third layer is regarded as early lunar regolith with 4

Radiation Shielding of Lunar Regolith/Polyethylene Composites and Lunar Regolith/Water Mixtures

Science.gov (United States)

Johnson, Quincy F.; Gersey, Brad; Wilkins, Richard; Zhou, Jianren

2011-01-01

Space radiation is a complex mixed field of ionizing radiation that can pose hazardous risks to sophisticated electronics and humans. Mission planning for lunar exploration and long duration habitat construction will face tremendous challenges of shielding against various types of space radiation in an attempt to minimize the detrimental effects it may have on materials, electronics, and humans. In late 2009, the Lunar Crater Observation and Sensing Satellite (LCROSS) discovered that water content in lunar regolith found in certain areas on the moon can be up to 5.6 +/-2.8 weight percent (wt%) [A. Colaprete, et. al., Science, Vol. 330, 463 (2010). ]. In this work, shielding studies were performed utilizing ultra high molecular weight polyethylene (UHMWPE) and aluminum, both being standard space shielding materials, simulated lunar regolith/ polyethylene composites, and simulated lunar regolith mixed with UHMWPE particles and water. Based on the LCROSS findings, radiation shielding experiments were conducted to test for shielding efficiency of regolith/UHMWPE/water mixtures with various percentages of water to compare relative shielding characteristics of these materials. One set of radiation studies were performed using the proton synchrotron at the Loma Linda Medical University where high energy protons similar to those found on the surface of the moon can be generated. A similar experimental protocol was also used at a high energy spalation neutron source at Los Alamos Neutron Science Center (LANSCE). These experiments studied the shielding efficiency against secondary neutrons, another major component of space radiation field. In both the proton and neutron studies, shielding efficiency was determined by utilizing a tissue equivalent proportional counter (TEPC) behind various thicknesses of shielding composite panels or mixture materials. Preliminary results from these studies indicated that adding 2 wt% water to regolith particles could increase shielding of

Effects of varying environmental conditions on emissivity spectra of bulk lunar soils: Application to Diviner thermal infrared observations of the Moon

Science.gov (United States)

Donaldson Hanna, K. L.; Greenhagen, B. T.; Patterson, W. R.; Pieters, C. M.; Mustard, J. F.; Bowles, N. E.; Paige, D. A.; Glotch, T. D.; Thompson, C.

2017-02-01

Currently, few thermal infrared measurements exist of fine particulate (samples (e.g. minerals, mineral mixtures, rocks, meteorites, and lunar soils) measured under simulated lunar conditions. Such measurements are fundamental for interpreting thermal infrared (TIR) observations by the Diviner Lunar Radiometer Experiment (Diviner) onboard NASA's Lunar Reconnaissance Orbiter as well as future TIR observations of the Moon and other airless bodies. In this work, we present thermal infrared emissivity measurements of a suite of well-characterized Apollo lunar soils and a fine particulate (sample as we systematically vary parameters that control the near-surface environment in our vacuum chamber (atmospheric pressure, incident solar-like radiation, and sample cup temperature). The atmospheric pressure is varied between ambient (1000 mbar) and vacuum (radiation is varied between 52 and 146 mW/cm2, and the sample cup temperature is varied between 325 and 405 K. Spectral changes are characterized as each parameter is varied, which highlight the sensitivity of thermal infrared emissivity spectra to the atmospheric pressure and the incident solar-like radiation. Finally spectral measurements of Apollo 15 and 16 bulk lunar soils are compared with Diviner thermal infrared observations of the Apollo 15 and 16 sampling sites. This comparison allows us to constrain the temperature and pressure conditions that best simulate the near-surface environment of the Moon for future laboratory measurements and to better interpret lunar surface compositions as observed by Diviner.

Electrostatic Power Generation from Negatively Charged, Simulated Lunar Regolith

Science.gov (United States)

Choi, Sang H.; King, Glen C.; Kim, Hyun-Jung; Park, Yeonjoon

2010-01-01

Research was conducted to develop an electrostatic power generator for future lunar missions that facilitate the utilization of lunar resources. The lunar surface is known to be negatively charged from the constant bombardment of electrons and protons from the solar wind. The resulting negative electrostatic charge on the dust particles, in the lunar vacuum, causes them to repel each other minimizing the potential. The result is a layer of suspended dust about one meter above the lunar surface. This phenomenon was observed by both Clementine and Surveyor spacecrafts. During the Apollo 17 lunar landing, the charged dust was a major hindrance, as it was attracted to the astronauts' spacesuits, equipment, and the lunar buggies. The dust accumulated on the spacesuits caused reduced visibility for the astronauts, and was unavoidably transported inside the spacecraft where it caused breathing irritation [1]. In the lunar vacuum, the maximum charge on the particles can be extremely high. An article in the journal "Nature", titled "Moon too static for astronauts?" (Feb 2, 2007) estimates that the lunar surface is charged with up to several thousand volts [2]. The electrostatic power generator was devised to alleviate the hazardous effects of negatively charged lunar soil by neutralizing the charged particles through capacitive coupling and thereby simultaneously harnessing power through electric charging [3]. The amount of power generated or collected is dependent on the areal coverage of the device and hovering speed over the lunar soil surface. A thin-film array of capacitors can be continuously charged and sequentially discharged using a time-differentiated trigger discharge process to produce a pulse train of discharge for DC mode output. By controlling the pulse interval, the DC mode power can be modulated for powering devices and equipment. In conjunction with a power storage system, the electrostatic power generator can be a power source for a lunar rover or other

A Synthesis of VIIRS Solar and Lunar Calibrations

Science.gov (United States)

Eplee, Robert E.; Turpie, Kevin R.; Meister, Gerhard; Patt, Frederick S.; Fireman, Gwyn F.; Franz, Bryan A.; McClain, Charles R.

2013-01-01

The NASA VIIRS Ocean Science Team (VOST) has developed two independent calibrations of the SNPP VIIRS moderate resolution reflective solar bands using solar diffuser and lunar observations through June 2013. Fits to the solar calibration time series show mean residuals per band of 0.078-0.10%. There are apparent residual lunar libration correlations in the lunar calibration time series that are not accounted for by the ROLO photometric model of the Moon. Fits to the lunar time series that account for residual librations show mean residuals per band of 0.071-0.17%. Comparison of the solar and lunar time series shows that the relative differences in the two calibrations are 0.12-0.31%. Relative uncertainties in the VIIRS solar and lunar calibration time series are comparable to those achieved for SeaWiFS, Aqua MODIS, and Terra MODIS. Intercomparison of the VIIRS lunar time series with those from SeaWiFS, Aqua MODIS, and Terra MODIS shows that the scatter in the VIIRS lunar observations is consistent with that observed for the heritage instruments. Based on these analyses, the VOST has derived a calibration lookup table for VIIRS ocean color data based on fits to the solar calibration time series.

Geophysical evidence for melt in the deep lunar interior and implications for lunar evolution (Invited)

Science.gov (United States)

Khan, A.; Connolly, J. A.; Pommier, A.

2013-12-01

Analysis of lunar seismic and lunar laser ranging data has yielded evidence that has been interpreted to indicate a molten zone in the lower-most mantle and/or the outer core of the Moon. Such a zone would provide strong constraints on models of the thermal evolution of the Moon. Here we invert lunar geophysical data in combination with phase-equilibrium modeling to derive information about the thermo-chemical and physical structure of the deep lunar interior. Specifically, we assess whether a molten layer is required by the geophysical data and, if so, its likely composition and physical properties (e.g., density and seismic wave speeds). The data considered are mean mass and moment of inertia, second-degree tidal Love number, and frequency-dependent electromagnetic sounding data. The main conclusion drawn from this study is that a region with high dissipation located deep within the Moon is indeed required to explain the geophysical data. If this dissipative region is located within the mantle, then the solidus is crossed at a depth of ~1200 km (>1600 deg C). The apparent absence of far-side deep moonquakes (DMQs) is supporting evidence for a highly dissipative layer. Inverted compositions for the partially molten layer (typically 100--200 km thick) are enriched in FeO and TiO2 relative to the surrounding mantle. While the melt phase in >95 % of inverted models is neutrally buoyant at pressures of ~4.5--4.6 GPa, the melt contains less TiO2 (>~4 wt %) than the Ti-rich (~16 wt % TiO2) melts that produced a set of high-density primitive lunar magmas (~3.4 g/ccm). Melt densities computed here range from 3.3 to 3.4 g/ccm bracketing the density of lunar magmas with moderate-to-high TiO2 contents. Our results are consistent with a model of lunar evolution in which the cumulate pile formed from crystallization of the magma ocean as it overturned, trapping heat-producing elements in the lower mantle.

Uranium in the rock fragments from Lunar soil

International Nuclear Information System (INIS)

Komarov, A.N.; Sergeev, S.A.

1983-01-01

Uranium content and distribution in Lunar rock fragments 0.4-0.9 mm in size from ''Lunar-16+ -20, -24'' stations were studied by the method of autoradiography. Uranium is almost absent in rock-forming minerals and is concentrated in some accessory mineral. Uranium content in microgabro fragments from ''Lunar-20 and -24'' equals (0.0n - n.0)16 -6 g/g. Variations are not related to fragment representation. Radiogra-- phies of fragments from Lunar soil showed the uranium distribution from uniform (in glasses) to extremely nonuniform in some holocrystalline rocks. It was pointed out, that uranium micro distributions in Lunar and Earth (effusive and magmatic) rocks have common features. In both cases rock-forming minerals don't contain appreciable uranium amount in the form of isomorphic admixture; uranium is highly concentrated in some accessory minerais. The difference lies in tne absence of hydroxyl -containing secondary minerals, which are enriched with uranium on Earth, in Lunar rocks. ''Film'' uranium micromineralization, which occurs in rocks of the Earth along the boundaries of mineral grains is absent in Lunar rocks as well

Significance of zircon U-Pb ages from the Pescadero felsite, west-central California coast ranges

Science.gov (United States)

McLaughlin, Robert J.; Moore, Diane E.; ,; Martens, UWE C.; Clark, J.C.

2011-01-01

Weathered felsite is associated with the late Campanian–Maastrichtian Pigeon Point Formation near Pescadero, California. Poorly exposed, its age and correlation are uncertain. Is it part of the Pigeon Point section west of the San Gregorio–Hosgri fault? Does it rest on Nacimiento block basement? Is it dextrally offset from the Oligocene Cambria Felsite, ∼185 km to the southeast? Why is a calc-alkaline hypabyssal igneous rock intrusive into the outboard accretionary prism? To address these questions, we analyzed 43 oscillatory-zoned zircon crystals from three incipiently recrystallized pumpellyite ± prehnite ± laumontite-bearing Pescadero felsite samples by sensitive high-resolution ion microprobe–reverse geometry (SHRIMP-RG) and laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) techniques. Thirty-three zircons gave late Mesozoic U-Pb ages, with single-grain values ranging from 81 to 167 Ma; ten have pre-Mesozoic, chiefly Proterozoic ages. A group of the four youngest Pescadero zircons yielded an apparent maximum igneous age of ca. 86–90 Ma. Reflecting broad age scatter and presence of partly digested sandstone inclusions, we interpret the rest of the zircons (perhaps all) as xenocrysts. Twenty-three zircons were separated and analyzed from two samples of the similar Cambria Felsite, yielding a unimodal 27 Ma U-Pb age. Clearly, the origin of the Upper Oligocene Cambria Felsite is different from that of the Upper Cretaceous Pescadero felsite; these rocks are not correlated, and do not constrain displacement along the San Gregorio–Hosgri fault. Peak ages differ slightly, but relative probability curves for Mesozoic and pre-Mesozoic Pescadero zircons compare well, for example, with abundant U-Pb age data for detrital zircons from Franciscan metaclastic strata ∼100 km to the east in the Diablo Range–San Francisco Bay area, San Joaquin Great Valley Group turbidites, Upper Cretaceous Nacimiento block Franciscan strata, and Upper

Retention capacity of samarium (III) in zircon for it possible use in retaining walls for confinement of nuclear residues

International Nuclear Information System (INIS)

Garcia G, N.

2006-01-01

Mexico, as country that produces part of its electric power by nuclear means, should put special emphasis in the development of technologies guided to the sure and long term confinement of the high level nuclear residuals. This work studies the capacity that has the natural zircon to retain to the samarium (III) in solution, by what due, firstly, to characterize the zircon for technical instrumental to determine the purity and characteristic of the mineral in study. The instrumental techniques that were used to carry out the physicochemical characterization were the neutron activation analysis (NAA), the infrared spectroscopy (IS), the thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), semiquantitative analysis, dispersive energy spectroscopy (EDS), X-ray diffraction (XRD) and luminescence technique. The characterization of the surface properties carries out by means of the determination of the surface area using the BET multipoint technique, acidity constants, hydration time, the determination of the point of null charge (pH PCN ) and density of surface sites (D s ). The luminescence techniques were useful to determine the optimal point hydration of the zircon and for the quantification of the samarium, for that here intends the development of both analysis techniques. With the adjustment of the titration curves in the FITEQL 4 package the constants of surface acidity in the solid/liquid interface were determined. To the finish of this study it was corroborated that the zircon is a mineral that presents appropriate characteristics to be proposed as a contention barrier for the deep geologic confinement. With regard to the study of adsorption that one carries out the samarium retention it is superior to 90% under the described conditions. This investigation could also be applicable in the confinement of dangerous industrial residuals. (Author)

A Multispectral Micro-Imager for Lunar Field Geology

Science.gov (United States)

Nunez, Jorge; Farmer, Jack; Sellar, Glenn; Allen, Carlton

2009-01-01

Field geologists routinely assign rocks to one of three basic petrogenetic categories (igneous, sedimentary or metamorphic) based on microtextural and mineralogical information acquired with a simple magnifying lens. Indeed, such observations often comprise the core of interpretations of geological processes and history. The Multispectral Microscopic Imager (MMI) uses multi-wavelength, light-emitting diodes (LEDs) and a substrate-removed InGaAs focal-plane array to create multispectral, microscale reflectance images of geological samples (FOV 32 X 40 mm). Each pixel (62.5 microns) of an image is comprised of 21 spectral bands that extend from 470 to 1750 nm, enabling the discrimination of a wide variety of rock-forming minerals, especially Fe-bearing phases. MMI images provide crucial context information for in situ robotic analyses using other onboard analytical instruments (e.g. XRD), or for the selection of return samples for analysis in terrestrial labs. To further assess the value of the MMI as a tool for lunar exploration, we used a field-portable, tripod-mounted version of the MMI to image a variety of Apollo samples housed at the Lunar Experiment Laboratory, NASA s Johnson Space Center. MMI images faithfully resolved the microtextural features of samples, while the application of ENVI-based spectral end member mapping methods revealed the distribution of Fe-bearing mineral phases (olivine, pyroxene and magnetite), along with plagioclase feldspars within samples. Samples included a broad range of lithologies and grain sizes. Our MMI-based petrogenetic interpretations compared favorably with thin section-based descriptions published in the Lunar Sample Compendium, revealing the value of MMI images for astronaut and rover-mediated lunar exploration.

Experimental Fractional Crystallization of the Lunar Magma Ocean

Science.gov (United States)

Rapp, J. F.; Draper, D. S.

2012-01-01

The current paradigm for lunar evolution is of crystallization of a global scale magma ocean, giving rise to the anorthositic crust and mafic cumulate interior. It is thought that all other lunar rocks have arisen from this differentiated interior. However, until recently this paradigm has remained untested experimentally. Presented here are the first experimental results of fractional crystallization of a Lunar Magma Ocean (LMO) using the Taylor Whole Moon (TWM) bulk lunar composition [1].

Plume Mitigation: Soil Erosion and Lunar Prospecting Sensor Project

Science.gov (United States)

Metzger, Philip T.

2014-01-01

Demonstrate feasibility of the simplest, lowest-mass method of measuring density of a cloud of lunar soil ejected by rocket exhaust, using new math techniques with a small baseline laser/camera system. Focus is on exploring the erosion process that occurs when the exhaust plume of a lunar rocket impacts the regolith. Also, predicting the behavior of the lunar soil that would be blasted from a lunar landing/launch site shall assist in better design and protection of any future lunar settlement from scouring of structures and equipment. NASA is gathering experimental data to improve soil erosion models and understand how lunar particles enter the plume flow.

Experimental reduction of simulated lunar glass by carbon and hydrogen and implications for lunar base oxygen production

International Nuclear Information System (INIS)

Mckay, D.S.; Morris, R.V.; Jurewicz, A.J.

1991-01-01

The most abundant element in lunar rocks and soils is oxygen which makes up approximately 45 percent by weight of the typical lunar samples returned during the Apollo missions. This oxygen is not present as a gas but is tightly bound to other elements in mineral or glass. When people return to the Moon to explore and live, the extraction of this oxygen at a lunar outpost may be a major goal during the early years of operation. Among the most studied processes for oxygen extraction is the reduction of ilmenite by hydrogen gas to form metallic iron, titanium oxide, and oxygen. A related process is proposed which overcomes some of the disadvantages of ilmenite reduction. It is proposed that oxygen can be extracted by direct reduction of native lunar pyroclactic glass using either carbon, carbon monoxide, or hydrogen. In order to evaluate the feasibility of this proposed process a series of experiments on synthetic lunar glass are presented. The results and a discussion of the experiments are presented

Lunar sample studies

International Nuclear Information System (INIS)

1977-01-01

Lunar samples discussed and the nature of their analyses are: (1) an Apollo 15 breccia which is thoroughly analyzed as to the nature of the mature regolith from which it derived and the time and nature of the lithification process, (2) two Apollo 11 and one Apollo 12 basalts analyzed in terms of chemistry, Cross-Iddings-Pirsson-Washington norms, mineralogy, and petrography, (3) eight Apollo 17 mare basalts, also analyzed in terms of chemistry, Cross-Iddings-Pirsson-Washington norms, mineralogy, and petrography. The first seven are shown to be chemically similar although of two main textural groups; the eighth is seen to be distinct in both chemistry and mineralogy, (4) a troctolitic clast from a Fra Mauro breccia, analyzed and contrasted with other high-temperature lunar mineral assemblages. Two basaltic clasts from the same breccia are shown to have affinities with rock 14053, and (5) the uranium-thorium-lead systematics of three Apollo 16 samples are determined; serious terrestrial-lead contamination of the first two samples is attributed to bandsaw cutting in the lunar curatorial facility

Infrared Lunar Laser Ranging at Calern : Impact on Lunar Dynamics

Science.gov (United States)

Viswanathan, Vishnu; Fienga, Agnes; Manche, Herve; Gastineau, Mickael; Courde, Clement; Torre, Jean Marie; Exertier, Pierre; Laskar, Jacques

2017-04-01

Introduction: Since 2015, in addition to the traditional green (532nm), infrared (1064nm) has been the preferred wavelength for lunar laser ranging at the Calern lunar laser ranging (LLR) site in France. Due to the better atmospheric transmission of IR with respect to Green, nearly 3 times the number of normal points have been obtained in IR than in Green [1]. Dataset: In our study, in addition to the historical data obtained from various other LLR sites, we include the recent IR normal points obtained from Calern over the 1 year time span (2015-2016), constituting about 4.2% of data spread over 46 years of LLR. Near even distribution of data provided by IR on both the spatial and temporal domain, helps us to improve constraints on the internal structure of the Moon modeled within the planetary ephemeris : INPOP [2]. Data reduction: IERS recommended models have been used in the data reduction software GINS (GRGS,CNES) [3]. Constraints provided by GRAIL [4], on the Lunar gravitational potential and Love numbers have been taken into account in the least-square fit procedure. Earth orientation parameters from KEOF series have been used as per a recent study [5]. Results: New estimates on the dynamical parameters of the lunar core will be presented. Acknowledgements: We thank the lunar laser ranging observers at Observatoire de la Côte d'Azur, France, McDonald Observatory, Texas, Haleakala Observatory, Hawaii, and Apache Point Observatory in New Mexico for providing LLR observations that made this study possible. The research described in this abstract was carried out at Geoazur-CNRS, France, as a part of a PhD thesis funded by Observatoire de Paris and French Ministry of Education and Research. References: [1] Clement C. et al. (2016) submitted to A&A [2] Fienga A. et al. (2015) Celest Mech Dyn Astr, 123: 325. doi:10.1007/s10569-015-9639-y [3] Viswanathan V. et al. (2015) EGU, Abstract 18, 13995 [4] Konopliv A. S. et al. (2013) J. Geophys. Res. Planets, 118, 1415

Isotopes as tracers of the sources of the lunar material and processes of lunar origin.

Science.gov (United States)

Pahlevan, Kaveh

2014-09-13

Ever since the Apollo programme, isotopic abundances have been used as tracers to study lunar formation, in particular to study the sources of the lunar material. In the past decade, increasingly precise isotopic data have been reported that give strong indications that the Moon and the Earth's mantle have a common heritage. To reconcile these observations with the origin of the Moon via the collision of two distinct planetary bodies, it has been proposed (i) that the Earth-Moon system underwent convective mixing into a single isotopic reservoir during the approximately 10(3) year molten disc epoch after the giant impact but before lunar accretion, or (ii) that a high angular momentum impact injected a silicate disc into orbit sourced directly from the mantle of the proto-Earth and the impacting planet in the right proportions to match the isotopic observations. Recently, it has also become recognized that liquid-vapour fractionation in the energetic aftermath of the giant impact is capable of generating measurable mass-dependent isotopic offsets between the silicate Earth and Moon, rendering isotopic measurements sensitive not only to the sources of the lunar material, but also to the processes accompanying lunar origin. Here, we review the isotopic evidence that the silicate-Earth-Moon system represents a single planetary reservoir. We then discuss the development of new isotopic tracers sensitive to processes in the melt-vapour lunar disc and how theoretical calculations of their behaviour and sample observations can constrain scenarios of post-impact evolution in the earliest history of the Earth-Moon system. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Lunar plant biology--a review of the Apollo era.

Science.gov (United States)

Ferl, Robert J; Paul, Anna-Lisa

2010-04-01

Recent plans for human return to the Moon have significantly elevated scientific interest in the lunar environment with emphasis on the science to be done in preparation for the return and while on the lunar surface. Since the return to the Moon is envisioned as a dedicated and potentially longer-term commitment to lunar exploration, questions of the lunar environment and particularly its impact on biology and biological systems have become a significant part of the lunar science discussion. Plants are integral to the discussion of biology on the Moon. Plants are envisioned as important components of advanced habitats and fundamental components of advanced life-support systems. Moreover, plants are sophisticated multicellular eukaryotic life-forms with highly orchestrated developmental processes, well-characterized signal transduction pathways, and exceedingly fine-tuned responses to their environments. Therefore, plants represent key test organisms for understanding the biological impact of the lunar environment on terrestrial life-forms. Indeed, plants were among the initial and primary organisms that were exposed to returned lunar regolith from the Apollo lunar missions. This review discusses the original experiments involving plants in association with the Apollo samples, with the intent of understanding those studies within the context of the first lunar exploration program and drawing from those experiments the data to inform the studies critical within the next lunar exploration science agenda.

Fabrication and electrical characterization of 15% yttrium-doped barium zirconate-nitrate freeze drying method combined with vacuum heating

International Nuclear Information System (INIS)

Imashuku, Susumu; Uda, Tetsuya; Nose, Yoshitaro; Awakura, Yasuhiro

2011-01-01

Research highlights: → Very fine 15% yttrium-doped barium zirconate powder of particle size about 30 nm was obtained by synthesizing at 500 deg. C in vacuum from powder mixed by the nitrate freeze-drying method. → Large and homogeneous grains of 15% yttrium-doped barium zirconate were easily obtained using the synthesized powder. → Grain boundary resistance was not inversely proportional to the grain size as theoretically expected. → Specific grain boundary conductivity varies with samples because impurities and/or evaporation loss of barium oxide might affect the grain-boundary resistance in 15% yttrium-doped barium zirconate. - Abstract: We applied a nitrate freeze-drying method to obtain a fine synthesized powder of 15% yttrium-doped barium zirconate. Fine 15% yttrium-doped barium zirconate powder of particle size about 30 nm was obtained by synthesizing at 500 deg. C in vacuum from a powder mixed by the nitrate freeze-drying method. However, we could not obtain such fine powder by synthesizing in air. Using the powder synthesized in vacuum, large and homogeneous grains of 15% yttrium-doped barium zirconate were easily obtained after sintering. Then, the bulk and grain boundary resistance were evaluated by AC 2-terminal measurement of sample in the form of bar and pellet and DC 4-terminal measurement of bar-shape sample. The grain boundary resistance was not inversely proportional to the grain size as theoretically expected. We concluded that specific grain boundary conductivity varies with samples. Some impurities, evaporation loss of barium oxide and/or other unexpected reasons might affect the grain boundary resistance in 15% yttrium-doped barium zirconate.

Zircon U-Pb age and Hf-O isotopes of felsic rocks from the Atlantis Bank, Southwest Indian Ridge

Science.gov (United States)

Liu, C. Z.; Zhang, W. Q.

2017-12-01

Hole U1473A was drilled to 790 meters below seafloor on the Atlantis Bank, an oceanic core complex in the Southwest Indian Ridge, where the upper crust has been removed by detachment faulting. The recovered core consists dominantly of olivine gabbro, with subordinate gabbro, gabbro with varying Fe-Ti oxide concentrations. Felsic veins intermittently occur throughout the whole core section. Zircons separated from twenty-four felsic samples have been conducted for U-Pb dating and O isotope analyses on the Cameca 1280 and Lu-Hf isotopes by laser ablation coupled with a MC-ICPMS. The zircons have highly variable contents of U (12-2078 ppm) and Th (5-801 ppm), yielding Th/U ratios of 0.33-0.81. They are typical oceanic zircons as defined by the trace element discrimination plots of Grimes et al. (2015). The weighted mean 206Pb/238U ages of the analyzed zircons vary from 11.29 to 12.57 Ma. Age differences between felsic veins throughout the whole core are not resolved within analytical uncertainty of the SIMS measurements. All felsic samples have similar zircon Hf isotope compositions, with initial 176Hf/177Hf ratios of 0.283126-0.283197 and ɛHf values of 12.76-15.27. Zircons from all felsic samples but one have mantle-like δ18O values of 5.14-5.50‰. Zircons from one sample show partial resorption or total recrystallization; in comparison, they have lower δ18O values of 4.81±0.21‰. Such characteristics provide clear evidence for hydrothermal alteration after magmatic intrusion.

Evolution of the Gondwanaland Archaean Shield: ion microprobe zircon dating and southwestern Australia/Wilkes Land, Antartica

International Nuclear Information System (INIS)

Lovering, J.F.; Comaford, D.J.

1979-01-01

The ion microprobe has been used to study 207 Pb/ 206 Pb ages on 20μm-sized sites on single zircon grains from coastal rocks on either side of the rift in the Gondwanaland Archaean Shield between southwestern Australia and Wilkes Land, Antarctica. The ages on individual sites on zircon grains from a variety of rock types from southwestern Australia show a range from 1600 m.y. to about 3400 m.y., with an inverse dependence on the uranium abundance at each site. Ages of zircons from rocks from the Antartic region show a range from 1600 m.y. to 3100 m.y

Global silicate mineralogy of the Moon from the Diviner lunar radiometer.

Science.gov (United States)

Greenhagen, Benjamin T; Lucey, Paul G; Wyatt, Michael B; Glotch, Timothy D; Allen, Carlton C; Arnold, Jessica A; Bandfield, Joshua L; Bowles, Neil E; Donaldson Hanna, Kerri L; Hayne, Paul O; Song, Eugenie; Thomas, Ian R; Paige, David A

2010-09-17

We obtained direct global measurements of the lunar surface using multispectral thermal emission mapping with the Lunar Reconnaissance Orbiter Diviner Lunar Radiometer Experiment. Most lunar terrains have spectral signatures that are consistent with known lunar anorthosite and basalt compositions. However, the data have also revealed the presence of highly evolved, silica-rich lunar soils in kilometer-scale and larger exposures, expanded the compositional range of the anorthosites that dominate the lunar crust, and shown that pristine lunar mantle is not exposed at the lunar surface at the kilometer scale. Together, these observations provide compelling evidence that the Moon is a complex body that has experienced a diverse set of igneous processes.

Lunar heat-flow experiment

Science.gov (United States)

Langseth, M. G.

1977-01-01

The principal components of the experiment were probes, each with twelve thermometers of exceptional accuracy and stability, that recorded temperature variations at the surface and in the regolith down to 2.5 m. The Apollo 15 experiment and the Apollo 17 probes recorded lunar surface and subsurface temperatures. These data provided a unique and valuable history of the interaction of solar energy with lunar surface and the effects of heat flowing from the deep interior out through the surface of the moon. The interpretation of these data resulted in a clearer definition of the thermal and mechanical properties of the upper two meters of lunar regolith, direct measurements of the gradient in mean temperature due to heat flow from the interior and a determination of the heat flow at the Apollo 15 and Apollo 17 sites.

Detrital Zircons From the Jack Hills and Mount Narryer, Western Australia: Geochronological, Morphological, and Geochemical Evidence for Diverse >4000 Ma Source Rocks

Science.gov (United States)

Crowley, J. L.; Myers, J. S.; Sylvester, P. J.; Cox, R. A.

2004-05-01

Detrital zircons from all major clastic units in the Jack Hills and Mount Narryer metasedimentary belts, Western Australia, were analyzed for morphology, internal zoning, inclusion mineralogy, age, and trace element concentrations (latter two obtained by laser-ablation microprobe ICPMS). The results show that zircons were derived from a wide diversity of rocks, including previously described, >4000 Ma grains that are older than any known terrestrial rocks. In three metaconglomerate samples from the western Jack Hills, 4200-3800 Ma zircons ("old grains") comprise 14% of the population, 3800-3600 Ma grains form only 2%, and 3550-3250 Ma zircons ("young grains") are dominant with a significant peak at 3380 Ma. Old and young grains are interpreted as being from similar rock types because they are indistinguishable in trace element concentrations, size (several hundred microns), morphology (subequant, typically fragmented), internal zoning (typically both oscillatory and sector), and U concentration (50-200 ppm). Many of these properties suggest an intermediate plutonic source, whereas an evolved granitic source was previously interpreted from rare-earth element and oxygen isotope data. Detrital zircons in quartzites and metaconglomerates at Mount Narryer differ significantly from zircons from the western Jack Hills. Old grains comprise only 3% (most of which are 4200-4100 Ma), 3800-3600 Ma zircons form 31%, and there are peaks at 3650, 3600, and 3500 Ma. Old and young grains have similar properties that suggest granitic sources, such as elongate prismatic morphology, oscillatory zoning, high U concentrations (100-600 ppm), and xenotime and monazite inclusions. Trace element concentrations are broadly similar to those in Jack Hills zircons, with notable exceptions being generally higher U, smaller Ce and Eu anomalies, and lower Nb/Ta. It is considered unlikely that Jack Hills zircons were derived from granitic gneisses that surround the metasedimentary belts because

Lunar Flashlight

Data.gov (United States)

National Aeronautics and Space Administration — Lunar Flashlight (LF) is an innovative cubesat mission sponsored by NASA’s Advanced Exploration Systems (AES) division to be launched on the Space Launch System...

A study of a production process for hafnium-free zirconium from zircon

International Nuclear Information System (INIS)

Ratanalert, N.

1985-01-01

The purpose of this experiment was to extract and purify the zirconium from zircon. The effects of time of extraction and stripping of zirconium, concentration of feed solution, concentration of hydrochloric acid in stripping process, equilibrium curve of extraction of zirconium and hafnium and equilibrium curve of stripping zirconium or scrubbing hafnium were studied from standard zirconium and hafnium. The results, subsequently were applied to the extraction procedures for zirconium from zircon. Minus 100 mesh zircon was fused with sodium hydroxide in the ratio of 1 : 6 at 700 degree C for l hour. After fusion the zirconate was leached with water and dissolved in hot concentrated hydrochloric acid. Zirconyl chloride octahydrate crystallized out when the solution was cooled. An agueons solution of zirconyl chloride was used as the feed to the hexone - thiocyanate solvent extraction process. This was prepared by dissolving zirconyl chloride octahydrate crystal in waster. This zirconium feed solution in 1 M HCl and 1 M N H 4 CNS was extracted with 2.7 m N H 4 CNS in hexone and then stripped with 3.6 M HCl the aqueous phase was got rid of thiocyanate ion by extracting with pure hexone, then the zirconium in aqueous phase was precipitated with sulfuric acid and ammonium hydroxide at pH 1.8 - 2.0 and zirconium oxide was obtained by ignition at 700 degree C. The process could be modified to improve the purity of zirconium by using cation exchange resin to get rid of thiocyanate ion after solvent extraction process

Zirconium oxide obtainment from brazilian zircon concentrate

International Nuclear Information System (INIS)

Ribeiro, S.; Martins, A.H.

1991-01-01

This work presents the experimental results of studies about alkaline melting, acid leaching and sulfation steps for obtention of zirconium oxide and partially stabilized zirconia by yttrium and rare-earth coprecipitation in chlorine medium, starting from the brazilian zircon concentrate. Using statistical methods of factorial design and the Packett-Burman approach, the results are discussed and the optimal conditions of the production steps were determined. (author)

Optimal Lunar Landing Trajectory Design for Hybrid Engine

OpenAIRE

Cho, Dong-Hyun; Kim, Donghoon; Leeghim, Henzeh

2015-01-01

The lunar landing stage is usually divided into two parts: deorbit burn and powered descent phases. The optimal lunar landing problem is likely to be transformed to the trajectory design problem on the powered descent phase by using continuous thrusters. The optimal lunar landing trajectories in general have variety in shape, and the lunar lander frequently increases its altitude at the initial time to obtain enough time to reduce the horizontal velocity. Due to the increment in the altitude,...

Crustal growth history of the Korean Peninsula:Constraints from detrital zircon ages in modern river sediments

Institute of Scientific and Technical Information of China (English)

Taejin Choi; Yong Il Lee; Yuji Orihashi

2016-01-01

U-Pb analyses were carried out on detrital zircon grains from major river-mouth sediments draining South Korea to infer provenance characteristics and the crustal growth history of the southern Korean Peninsula, using a laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS). The Korean Peninsula is located in the East Asian continental margin and mainly comprises three Precambrian massifs and two metamorphic belts in between them. We obtained 515 concordant to slightly discordant zircon ages ranging from ca. 3566 to ca. 48 Ma. Regardless of river-mouth location, predominance of Mesozoic (249e79 Ma) and Paleoproterozoic (2491e1691 Ma) ages with subordinate Archean ages in-dicates that the zircon ages reflect present exposures of plutonic/metamorphic rocks in the drainage basins of the South Korean rivers and the crustal growth of the southern Korean Peninsula was focused in these two periods. Comparison of detrital zircon-age data between the North and South Korean river sediments reveals that the Paleoproterozoic zircon age distributions of both regions are nearly identical, while the NeoproterozoicePaleozoic ages exist and the Mesozoic ages are dominant in southern Korean Peninsula. This result suggests that Precambrian terrains in Korea record the similar pre-Mesozoic magmatic history and that the influence of Mesozoic magmatism was mainly focused in South Korea.

Distribution of Amino Acids in Lunar Regolith

Science.gov (United States)

Elsila, J. E.; Callahan, M. P.; Glavin, D. P.; Dworkin, J. P.; Noble, S. K.; Gibson, E. K., Jr.

2014-01-01

One of the most eagerly studied questions upon initial return of lunar samples was whether significant amounts of organic compounds, including amino acids, were present. Analyses during the 1970s produced only tentative and inconclusive identifications of indigenous amino acids. Those analyses were hampered by analytical difficulties including relative insensitivity to certain compounds, the inability to separate chiral enantiomers, and the lack of compound-specific isotopic measurements, which made it impossible to determine whether the detected amino acids were indigenous to the lunar samples or the results of contamination. Numerous advances have been made in instrumentation and methodology for amino acid characterization in extraterrestrial samples in the intervening years, yet the origin of amino acids in lunar regolith samples has been revisited only once for a single lunar sample, (3) and remains unclear. Here, we present initial data from the analyses of amino acid abundances in 12 lunar regolith samples. We discuss these abundances in the context of four potential amino acid sources: (1) terrestrial biological contamination; (2) contamination from lunar module (LM) exhaust; (3) derivation from solar windimplanted precursors; and (4) exogenous delivery from meteorites.

Line Profile Measurements of the Lunar Exospheric Sodium

Science.gov (United States)

Oliversen, Ronald J.; Mierkiewicz, Edwin J.; Line, Michael R.; Roesler, Fred L.; Lupie, Olivia L.

2012-01-01

We report ongoing results of a program to measure the lunar sodium exospheric line profile from near the lunar limb out to two lunar radii (approx 3500 km). These observations are conducted from the National Solar Observatory McMath-Pierce telescope using a dual-etalon Fabry-Perot spectrometer with a resolving power of 180,600 (1.7 km/s) to measure line widths and velocity shifts of the Na D2 (5889 950 A) emission line in equatorial and polar regions at different lunar phases. The typical field of view (FOV) is 3 arcmin (approx 360 km) with an occasional smaller 1 arcmin FOV used right at the limb edge. The first data were obtained from full Moon to 3 days following full Moon (waning phase) in March 2009 as part of a demonstration run aimed at establishing techniques for a thorough study of temperatures and velocity variations in the lunar sodium exosphere. These data indicate velocity displacements from different locations off the lunar limb range between 150 and 600 m/s from the lunar rest velocity with a precision of +/- 20 to +/- 50 m/s depending on brightness. The measured Doppler line widths for observations within 10.5 arcmin of the east and south lunar limbs for observations between 5 deg and 40 deg lunar phase imply temperatures ranging decreasing from 3250 +/- 260K to 1175 +/- 150K. Additional data is now being collected on a quarterly basis since March 2011 and preliminary results will be reported.

Lunar surface fission power supplies: Radiation issues

International Nuclear Information System (INIS)

Houts, M.G.; Lee, S.K.

1994-01-01

A lunar space fission power supply shield that uses a combination of lunar regolith and materials brought from earth may be optimal for early lunar outposts and bases. This type of shield can be designed such that the fission power supply does not have to be moved from its landing configuration, minimizing handling and required equipment on the lunar surface. Mechanisms for removing heat from the lunar regolith are built into the shield, and can be tested on earth. Regolith activation is greatly reduced compared with a shield that uses only regolith, and it is possible to keep the thermal conditions of the fission power supply close to these seen in free space. For a well designed shield, the additional mass required to be brought fro earth should be less than 1000 kg. Detailed radiation transport calculations confirm the feasibility of such a shield

Lunar surface fission power supplies: Radiation issues

International Nuclear Information System (INIS)

Houts, M.G.; Lee, S.K.

1994-01-01

A lunar space fission power supply shield that uses a combination of lunar regolith and materials brought from earth may be optimal for early lunar outposts and bases. This type of shield can be designed such that the fission power supply does not have to be moved from its landing configuration, minimizing handling and required equipment on the lunar surface. Mechanisms for removing heat from the lunar regolith are built into the shield, and can be tested on earth. Regolith activation is greatly reduced compared with a shield that uses only regolith, and it is possible to keep the thermal conditions of the fission power supply close to those seen in free space. For a well designed shield, the additional mass required to be brought from earth should be less than 1,000 kg. Detailed radiation transport calculations confirm the feasibility of such a shield

High temperature studies on scheelite and zircon type ThGeO4

International Nuclear Information System (INIS)

Patwe, S.J.; Achary, S.N.; Tyagi, A.K.

2008-01-01

The detailed structural analyses of two polymorphs of ThGeO 4 , namely, zircon (stable) and scheelite (metastable) types have been carried out from the in situ high temperature X-ray diffraction studies. Though both the polymorphs show positive thermal expansion, the coefficient of volume thermal expansion of scheelite modification is almost double of that for zircon modification. The anisotropies in thermal expansion behaviors are also different for the two modifications. The differences in thermal expansion behaviors have been explained from the differences in structural arrangements and anisotropy of the ThO 8 polyhedra in these two modifications. (author)

The 3.5 Ga granulites of the Bug polymetamorphic complex, Ukraine (U-Pb SHRIMP-II zircon data)

Science.gov (United States)

Lobach-Zhuchenko, Svetlana; Kaulina, Tatiana; Baltybaev, Shauket; Yurchenko, Anastasija; Balagansky, Victor; Skublov, Sergei; Sukach, Vitaliji

2014-05-01

The Bug polymetamorphic complex composes the south-west of the Ukrainian Shield. It experienced multistage deformation and metamorphism of 3.6 to 1.95 Ga. The age of protolith of the gneiss enderbite is up to 3.7-3.6 Ga (Claesson et al., 2006: Lobach-Zhuchenko et al., 2010, 2013; Bibikova et al, 2013). The 3.5 old granulitic zircon (sample UR132) was found in a light grey massive medium grained with weak foliation granulite from the Odessa quarry located at the right riverside of the Bug (N 48° 13' 55.2''; E 29° 59' 75''). The rock is mafic in composition (SiO2 = 51.50 wt%, #mg=0.43, (La/Yb)n =7.5), and shows enrichment in Sr (333 ppm), Zr (244 ppm), and Nb (12 ppm) compared to MORB. This contains antiperthitic plagioclase (An30-35), hypersthene (En0.46 Fs0.53 Wo0.01 ), diopside (En0.33 Fs0.20Wo0.47), quartz, ilmenite, magnetite, apatite, and zircon. Three types of zircon are recognized. (1) Large (~300 μm) isometric and oval grains displaying bright colour and sector zoning in CL. Some crystals have fir-tree texture. Isometric shape together with fir-tree zoning is typical for zircons growing under conditions of granulite- facies metamorphism (Hoskin and Schaltegger, 2003). These zircons are low in U and Th, have high Th/U ratios (0.61-1.1), and display decreasing of element contents from the centre to margin (ppm): U - 68 to 44, Th - 58 to 19, total REE - 723 to 406, Y - 1049 to 553, and Li - 1.23 to 0.91 at the constant (Lu/La)n ratios (4200-4600). Zircon's crystallization temperature calculated from the Ti content is 705 °C and is consistent with those calculated on the base of the mineral composition. (2) Small sized (60-100 μm) zircons. Most of these occur within plagioclase and truncate antiperthite lamellae. They show euhedral zoned cores and bright rims in CL. (3) Zircons principally distinguished from those of groups 1 and 2. These are dark in CL, some grains are severely structurally damaged and contain numerous inclusions (Qzt, Pl, Kfsp, rare Opx

Computer simulating observations of the Lunar physical libration for the Japanese Lunar project ILOM

Science.gov (United States)

Petrova, Natalia; Hanada, Hideo

2010-05-01

are calculated using the analytical theory of physical libration Petrova et al. (2008; 2009). We cannot use Newton's method for solution of the equation, because the Jacobian | | || δδfx11 δδfx12 δδf1x3-|| || δδfx2 δδfx2 δδf2x-|| J(X ) = || δf13 δf23 δ3f3-|| = 0. || δx1 δx2 δx3 || We transformed equations to the iteration form xi = φi(X). Used iteration methods have unsatisfactory convergence: inaccuracy in polar distance of 1 milliseconds of arc causes inaccuracy of 0.01arcsec in ρ and in Iσ, and 0.1 arcsec in ?. Results of our computer simulating showed It's necessary to carry out measuring of polar distances of stars in several meridians simultaneously to increase sample of stars. It's necessary to find additional links (relations) between observed parameters and libration angles to have stable mathematical methods to receive solutions for lunar rotation with high accuracy. The research was supported by the Russian-Japanese grant RFFI-JSPS 09-02-92113, (2009-2010) References: Hanada H., Noda H., Kikuchi F. et al., 2009. Different kind of observations of lunar rotation and gravity for SELENE-2. Proc of conf. Astrokazan-2009, August 19 - 26, Kazan, Russia. p. 172-175 Petrova N., Gusev A., Kawano N., Hanada H., 2008. Free librations of the two-layer Moon and the possibilities of their detection. Advances in Space Res., v 42, p. 1398-1404 Petrova N., Gusev A., Hanada H., Ivanova T., Akutina V., 2009. Application of the analytical theory of Lunar physical libration for simulating observations of stars for the future Japanese project ILOM. Proc of conf. Astrokazan-2009, August 19 - 26, Kazan, Russia. p.197 - 201.

Pan-African U-Pb zircon age from apatite-magnetite veins of eastern ghats granulite belt, India

International Nuclear Information System (INIS)

Kovach, V.P.; Salnikova, E.B.; Kotov, A.B.; Yakovleva, S.Z.; Rao, A.T.

1997-01-01

206 Pb/ 238 U ages of zircon correspond to 502±3 Ma and 207 Pb/ 206 Pb ages are equal to 508±14 Ma. U-Pb isotopic study of the Kasipatnam zircon has led to the recognition of pan-African thermal event in the eastern ghats granulite belt, India. (author)

Indigenous lunar construction materials

Science.gov (United States)

Rogers, Wayne P.; Sture, Stein

1991-01-01

The utilization of local resources for the construction and operation of a lunar base can significantly reduce the cost of transporting materials and supplies from Earth. The feasibility of processing lunar regolith to form construction materials and structural components is investigated. A preliminary review of potential processing methods such as sintering, hot-pressing, liquification, and cast basalt techniques, was completed. The processing method proposed is a variation on the cast basalt technique. It involves liquification of the regolith at 1200-1300 C, casting the liquid into a form, and controlled cooling. While the process temperature is higher than that for sintering or hot-pressing (1000-1100 C), this method is expected to yield a true engineering material with low variability in properties, high strength, and the potential to form large structural components. A scenario for this processing method was integrated with a design for a representative lunar base structure and potential construction techniques. The lunar shelter design is for a modular, segmented, pressurized, hemispherical dome which could serve as habitation and laboratory space. Based on this design, estimates of requirements for power, processing equipment, and construction equipment were made. This proposed combination of material processing method, structural design, and support requirements will help to establish the feasibility of lunar base construction using indigenous materials. Future work will refine the steps of the processing method. Specific areas where more information is needed are: furnace characteristics in vacuum; heat transfer during liquification; viscosity, pouring and forming behavior of molten regolith; design of high temperature forms; heat transfer during cooling; recrystallization of basalt; and refinement of estimates of elastic moduli, compressive and tensile strength, thermal expansion coefficient, thermal conductivity, and heat capacity. The preliminary

Fatigue studies in compensated bulk lead zirconate titanate

International Nuclear Information System (INIS)

Verdier, Cyril; Morrison, Finlay D.; Lupascu, Doru C.; Scott, James F.

2005-01-01

Impedance analysis studies were carried out on compensated bulk lead zirconate titanate samples. Fatigue is concomitant with the onset of dielectric loss. This is shown to be dominantly due to an irreversibly modified near-surface layer that can be polished off. The highly compensated nature of these samples minimizes the role of oxygen vacancies

Estimates of volume and magma input in crustal magmatic systems from zircon geochronology: the effect of modelling assumptions and system variables

Directory of Open Access Journals (Sweden)

Luca eCaricchi

2016-04-01

Full Text Available Magma fluxes in the Earth’s crust play an important role in regulating the relationship between the frequency and magnitude of volcanic eruptions, the chemical evolution of magmatic systems and the distribution of geothermal energy and mineral resources on our planet. Therefore, quantifying magma productivity and the rate of magma transfer within the crust can provide valuable insights to characterise the long-term behaviour of volcanic systems and to unveil the link between the physical and chemical evolution of magmatic systems and their potential to generate resources. We performed thermal modelling to compute the temperature evolution of crustal magmatic intrusions with different final volumes assembled over a variety of timescales (i.e., at different magma fluxes. Using these results, we calculated synthetic populations of zircon ages assuming the number of zircons crystallising in a given time period is directly proportional to the volume of magma at temperature within the zircon crystallisation range. The statistical analysis of the calculated populations of zircon ages shows that the mode, median and standard deviation of the populations varies coherently as function of the rate of magma injection and final volume of the crustal intrusions. Therefore, the statistical properties of the population of zircon ages can add useful constraints to quantify the rate of magma injection and the final volume of magmatic intrusions.Here, we explore the effect of different ranges of zircon saturation temperature, intrusion geometry, and wall rock temperature on the calculated distributions of zircon ages. Additionally, we determine the effect of undersampling on the variability of mode, median and standards deviation of calculated populations of zircon ages to estimate the minimum number of zircon analyses necessary to obtain meaningful estimates of magma flux and final intrusion volume.

Lunar dusty plasma: A result of interaction of the solar wind flux and ultraviolet radiation with the lunar surface

International Nuclear Information System (INIS)

Lisin, E A; Tarakanov, V P; Petrov, O F; Popel, S I

2015-01-01

One of the main problems of future missions to the Moon is associated with lunar dust. Solar wind flux and ultraviolet radiation interact with the lunar surface. As a result, there is a substantial surface change and a near-surface plasma sheath. Dust particles from the lunar regolith, which turned in this plasma because of any mechanical processes, can levitate above the surface, forming dust clouds. In preparing of the space experiments “Luna-Glob” and “Luna-Resource” particle-in-cell calculations of the near-surface plasma sheath parameters are carried out. Here we present some new results of particle-in-cell simulation of the plasma sheath formed near the surface of the moon as a result of interaction of the solar wind and ultraviolet radiation with the lunar surface. The conditions of charging and stable levitation of dust particles in plasma above the lunar surface are also considered. (paper)

Chemistry and structure of lunar and synthetic armalcolite

International Nuclear Information System (INIS)

Wechsler, B.A.; Prewitt, C.T.; Papike, J.J.

1976-01-01

A study of the chemical trends displayed by lunar armalcolites has been made in conjunction with single-crystal X-ray structure refinements of lunar and synthetic armalcolite in order to assess the possible importance of Ti 3+ in lunar armalcolite and to characterize the effects of cation substitutions on the structure. The apparent cation deficiences found in lunar armalcolites analyzed with the electron microprobe most likely reflect the presence of Ti 3+ , although the existence of vacancies cannot be ruled out. Structure refinements of an Apollo 17 armalcolite are consistent with either interpretation. These results support experimental evidence suggesting the presence of Ti 3+ in armalcolite and indicate that virtually all lunar armalcolites probably contain approximately 4-11 mol.% Ti 2 3+ Ti 4+ 0 5 component in solid solution. The cation distribution in lunar armalcolite is essentially completely ordered. However, synthetic crystals quenched from near 1200 0 C have been found to retain significant cation disorder. (Auth.)

Zinnia Germination and Lunar Soil Amendment

Science.gov (United States)

Reese, Laura

2017-01-01

Germination testing was performed to determine the best method for germinating zinnias. This method will be used to attempt to germinate the zinnia seeds produced in space. It was found that seed shape may be critically important in determining whether a seed will germinate or not. The ability of compost and worm castings to remediate lunar regolith simulant for plant growth was tested. It was found that neither treatment effectively improves plant growth in lunar regolith simulant. A potential method of improving lunar regolith simulant by mixing it with arcillite was discovered.

Adsorption of Hg on lunar samples

International Nuclear Information System (INIS)

Reed, G.W. Jr.; Jovanovic, S.

1985-01-01

Understanding the presence, migration mechanisms and trapping of indigneous gases and volatiles on the moon is the objective of this study. The rare gases Ar and Xe and highly volatile Hg 0 and Br 0 (and/or their compounds) have been determined to be present in the lunar regolith. Evidence for these elements in the moon was recently reviewed. Studies of the sorption behavior of Xe on lunar material have been carried out. We report here preliminary results of a study designed to rationalize the behavior of Hg in lunar material

Zircon U-Pb and Hf isotopic constraints on the magmatic evolution of the Northern Luzon Arc

Directory of Open Access Journals (Sweden)

Yu-Ming Lai

2018-01-01

Full Text Available The complete volcanic sequences restored in the Coastal Range of Taiwan are key archives for better understanding the magmatic and tectonic evolution of the Northern Luzon Arc. This paper reports (1 new zircon U-Pb ages and Hf isotopic data of fourteen volcanic samples from different sequences of four major volcanoes in the Coastal Range, (2 Hf isotopic data of dated magmatic and detrital zircons from two offshore volcanic islands, Lutao and Lanyu. These data indicate that the arc magmatism in the Coastal Range started at ~15 Ma, most active at ~9 Ma, and ceased at ~4.2 Ma. Magmatic zircons from the arc rocks show a significant variation in Hf isotopic composition, with εHf(T values varying from +24.9 to +4.8. As pointed out by our previous studies, old continental zircons that show Cathaysian-type ages and Hf isotope features are common in samples from the Yuemei, Chimei, and Lanyu volcanoes, supporting the notion for the influence of the existence of an accreted micro-continent or continental fragment plays a role in the petrogenesis. Such inherited zircons are not observed in the Chengkuang’ao and Tuluanshan volcanoes and uncommon in Lutao, implying the discontinuity or a limited extent of the accreted continental fragment. The εHf(T values are high and positive from ~15 - 8 Ma (+25 to +15; ±5ε-unit variation, and became lower from ~6 to 4.2 Ma (+20 to +8; ±6ε units and the lowest from ~1.3 Ma (+19 to +5; ±7ε units. Such a temporal variation in zircon Hf isotopic ratios can be also identified in whole-rock Hf and Nd isotopic compositions, which decrease from ~6 Ma when the Northern Luzon Arc may have started colliding with the Eurasian continental margin.

Towards the Next International Lunar Decade

Science.gov (United States)

Beldavs, Vidvuds

2016-07-01

The idea of an International Lunar Decade (ILD) germinated in work underway in the International Lunar Working Group (ILEWG) coordinated by ESA starting before 2000. Envisioned was an International Geophysical Year (IGY) inspired global collaborative undertaking to better understand the Moon, its origins and resources as a step towards lunar development and possible human settlement. By 2006 the ILD idea had evolved sufficiently that the ILEWG endorsed it and endorsement was also received from COSPAR [1] The Planetary Society under the leadership of Louis Friedman championed the ILD idea, received a grant from the Secure World Foundation to promote it at various conferences as well as to the United Nations Committee on the Peaceful Uses of Outer Space (COPUOS). Friedman made a presentation about ILD to COPUOS in February, 2007 [2]. Despite positive interest in the idea no member state of COPUOS chose to promote it. The ILD agenda was adopted by ILEWG and largely fulfilled by the member space agencies in the decade from 2007-2014, but without UN endorsement as a global initiative. In 2013 an idea for an International Lunar Decade took hold among a group of space activists that included ideas for an International Lunar Research Park [3], an International Lunar Geophysical Year and other elements including an article published by V. Beldavs in the Space Review on January 14, 2014 [4]. These various thought streams were brought to focus at the conference "The Next Giant Leap: Leveraging Lunar Assets for Sustainable Pathways to Space", November 9-13, 2014 in Hawaii that resulted in the International Lunar Decade Declaration [3] and the formation of the working group (ILDWG) to promote implementation of ILD. In 2015 numerous organizations and influential persons were approached and informed about the idea of a framework for international collaboration sustained over a decade to gain an understanding of the Moon and its resources and to develop the technologies and

Endogenous Lunar Volatiles: Insights into the Abundances of Volatiles in the Moon from Lunar Apatite

Science.gov (United States)

McCubbin, Francis

2016-01-01

At the time of publication of New Views of the Moon, it was thought that the Moon was bone dry with less than about 1 ppb H2O. However in 2007, initial reports at the 38th Lunar and Planetary Science Conference speculated that H-species were present in both apatites and pyroclastic volcanic lunar glasses. These early reports were later confirmed through peer-review, which motivated many subsequent studies on magmatic volatiles in and on the Moon within the last decade. Some of these studies have cast into question the post-Apollo view of lunar formation, the distribution and sources of volatiles in the Earth-Moon system, and the thermal and magmatic evolution of the Moon. The mineral apatite has been one of the pillars of this new field of study, and it will be the primary focus of this abstract. Although apatite has been used both to understand the abundances of volatiles in lunar systems as well as the isotopic compositions of those volatiles, the focus here will be on the abundances of F, Cl, and H2O. This work demonstrates the utility of apatite in advancing our understanding of lunar volatiles, hence apatite should be among the topics covered in the endogenous lunar volatile chapter in NVM II. Truncated ternary plot of apatite X-site occupancy (mol%) from highlands apatite and mare basalt apatite plotted on the relative volatile abundance diagram from. The solid black lines delineate fields of relative abundances of F, Cl, and H2O (on a weight basis) in the melt from which the apatite crystallized. The diagram was constructed using available apatite/melt partitioning data for fluorine, chlorine, and hydroxyl.

Evaluating the High School Lunar Research Projects Program

Science.gov (United States)

Shaner, A. J.; Shipp, S. S.; Allen, J.; Kring, D. A.

2012-12-01

The Center for Lunar Science and Exploration (CLSE), a collaboration between the Lunar and Planetary Institute and NASA's Johnson Space Center, is one of seven member teams of the NASA Lunar Science Institute (NLSI). In addition to research and exploration activities, the CLSE team is deeply invested in education and outreach. In support of NASA's and NLSI's objective to train the next generation of scientists, CLSE's High School Lunar Research Projects program is a conduit through which high school students can actively participate in lunar science and learn about pathways into scientific careers. The objectives of the program are to enhance 1) student views of the nature of science; 2) student attitudes toward science and science careers; and 3) student knowledge of lunar science. In its first three years, approximately 140 students and 28 teachers from across the United States have participated in the program. Before beginning their research, students undertake Moon 101, a guided-inquiry activity designed to familiarize them with lunar science and exploration. Following Moon 101, and guided by a lunar scientist mentor, teams choose a research topic, ask their own research question, and design their own research approach to direct their investigation. At the conclusion of their research, teams present their results to a panel of lunar scientists. This panel selects four posters to be presented at the annual Lunar Science Forum held at NASA Ames. The top scoring team travels to the forum to present their research. Three instruments have been developed or modified to evaluate the extent to which the High School Lunar Research Projects meets its objectives. These three instruments measure changes in student views of the nature of science, attitudes towards science and science careers, and knowledge of lunar science. Exit surveys for teachers, students, and mentors were also developed to elicit general feedback about the program and its impact. The nature of science

Lunar Plants

Data.gov (United States)

National Aeronautics and Space Administration — We present an open design for a first plant growth module on the Moon (LPX). The primary science goal of lunar habitat is to investigate germination and initial...

40Ar/39Ar dating and zircon chronochemistry for the Izu-Bonin rear arc, IODP site U1437

Science.gov (United States)

Schmitt, A. K.; Konrad, K.; Andrews, G. D.; Horie, K.; Brown, S. R.; Koppers, A. A. P.; Busby, C.; Tamura, Y.

2016-12-01

The scientific objective of IODP Expedition 350 drilling at Site U1437 (31°47.390'N, 139°01.580'E) was to reveal the "missing half of the subduction factory": the rear arc of a long-lived intraoceanic subduction zone. Site U1437 lies in a 50 km long and 20 km wide volcano-bounded basin, 90 km west of the Izu arc front, and is the only IODP site drilled in the rear arc. The Izu rear arc is dominated by Miocene basaltic to dacitic seamount chains, which strike at a high angle to the arc front. Radiometric dating targeted a single igneous unit (1390 mbsf), and fine to coarse volcaniclastic units for which we present zircon and 40Ar/39Ar (hornblende, plagioclase, and groundmass) age determinations. All zircons analyzed as grain separates were screened for contamination from drill-mud (Andrews et al., 2016) by analyzing trace elements and, where material was available, O and Hf isotope compositions. Igneous Unit 1 is a rhyolite sheet and yielded concordant in-situ and crystal separate U-Pb zircon ages (13.7±0.3 Ma; MSWD = 1.3; n = 40 spots), whereas the 40Ar/39Ar hornblende plateau age (12.9±0.3; MSWD = 1.1; n = 9 steps) is slightly younger, possibly reflecting pre-eruptive zircon crystallization, or alteration of hornblende. U-Pb zircon and 40Ar/39Ar plateau ages from samples above igneous Unit 1 are concordant with biostratigraphic and paleomagnetic ages (available to 1300 mbsf), but plagioclase and groundmass samples below 1300 m become younger with depth, hinting at post-depositional alteration. A single zircon from 1600 mbsf yielded a U-Pb age of 15.4±1.8 Ma; its trace element composition resembles other igneous zircons from U1437, and is tentatively interpreted as a Middle Miocene age for the lowermost lithostratigraphic unit VII. Oxygen and Hf isotopic values of igneous zircon indicate mantle origins, with some influence of assimilation of hydrothermally altered oceanic crust evident in sub-mantle oxygen isotopic compositions. Lessons from site U1437 are

Using the magmatic record to constrain the growth of continental crust-The Eoarchean zircon Hf record of Greenland

Science.gov (United States)

Fisher, Christopher M.; Vervoort, Jeffrey D.

2018-04-01

Southern West Greenland contains some of the best-studied and best-preserved magmatic Eoarchean rocks on Earth, and these provide an excellent vantage point from which to view long-standing questions regarding the growth of the earliest continental crust. In order to address the questions surrounding early crustal growth and complementary mantle depletion, we present Laser Ablation Split Stream (LASS) analyses of the U-Pb and Hf isotope compositions of zircon from eleven samples of the least-altered meta-igneous rocks from the Itsaq (Amîtsoq) Gneisses of the Isukasia and Nuuk regions of southern West Greenland. This analytical technique allows a less ambiguous approach to determining the age and Hf isotope composition of complicated zircon. Results corroborate previous findings that Eoarchean zircon from the Itsaq Gneiss (∼3.85 Ga to ∼3.63 Ga) were derived from a broadly chondritic source. In contrast to the Sm-Nd whole rock isotope record for southern West Greenland, the zircon Lu-Hf isotope record provides no evidence for early mantle depletion, nor does it suggest the presence of crust older than ∼3.85 Ga in Greenland. Utilizing LASS U-Pb and Hf data from the Greenland zircons studied here, we demonstrate the importance of focusing on the magmatic (rather than detrital) zircon record to more confidently understand early crustal growth and mantle depletion. We compare the Greenland Hf isotope data with other Eoarchean magmatic complexes such as the Acasta Gneiss Complex, Nuvvuagittuq greenstone belt, and the gneissic complexes of southern Africa, and all lack zircons with suprachondritic Hf isotope compositions. In total, these data suggest only a very modest volume of crust was produced during (or survived from) the Hadean and earliest Eoarchean. There remains no record of planet-scale early Earth mantle depletion in the Hf isotope record prior to 3.8 Ga.

Protoliths of enigmatic Archaean gneisses established from zircon inclusion studies: Case study of the Caozhuang quartzite, E. Hebei, China

Directory of Open Access Journals (Sweden)

Allen P. Nutman

2014-07-01

Full Text Available A diverse suite of Archaean gneisses at Huangbaiyu village in the North China Craton, includes rare fuchsite-bearing (Cr-muscovite siliceous rocks – known as the Caozhuang quartzite. The Caozhuang quartzite is strongly deformed and locally mylonitic, with silica penetration and pegmatite veining common. It contains abundant 3880–3600 Ma and some Palaeoarchaean zircons. Because of its siliceous nature, the presence of fuchsite and its complex zircon age distribution, it has until now been accepted as a (mature quartzite. However, the Caozhuang quartzite sample studied here is feldspathic. The shape and cathodoluminescence petrography of the Caozhuang quartzite zircons show they resemble those found in immature detrital sedimentary rocks of local provenance or in Eoarchaean polyphase orthogneisses, and not those in mature quartzites. The Caozhuang quartzite intra-zircon mineral inclusions are dominated by quartz, with lesser biotite, apatite (7% and alkali-feldspar, and most inclusions are morphologically simple. A Neoarchaean orthogneiss from near Huangbaiyu displays morphologically simple inclusions with much more apatite (73%, as is typical for fresh calc-alkaline granitoids elsewhere. Zircons were also examined from a mature conglomerate quartzite clast and an immature feldspathic sandstone of the overlying weakly metamorphosed Mesoproterozoic Changcheng System. These zircons have oscillatory zoning, showing they were sourced from igneous rocks. The quartzite clast zircons contain only rare apatite inclusions (<1%, with domains with apatite habit now occupied by intergrowths of muscovite + quartz ± Fe-oxides ± baddeleyite. We interpret that these were once voids after apatite inclusions that had dissolved during Mesoproterozoic weathering, which were then filled with clays ± silica and then weakly metamorphosed. Zircons in the immature feldspathic sandstone show a greater amount of preserved apatite (11%, but with petrographic

Lunar soil as shielding against space radiation

Energy Technology Data Exchange (ETDEWEB)

Miller, J. [Lawrence Berkeley National Laboratory, MS 83R0101, 1 Cyclotron Road, Berkeley, CA 94720 (United States)], E-mail: miller@lbl.gov; Taylor, L. [Planetary Geosciences Institute, Department of Earth and Planetary Sciences, University of Tennessee, Knoxville, TN 37996 (United States); Zeitlin, C. [Southwest Research Institute, Boulder, CO 80302 (United States); Heilbronn, L. [Department of Nuclear Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Guetersloh, S. [Department of Nuclear Engineering, Texas A and M University, College Station, TX 77843 (United States); DiGiuseppe, M. [Northrop Grumman Corporation, Bethpage, NY 11714 (United States); Iwata, Y.; Murakami, T. [National Institute of Radiological Sciences, Chiba 263-8555 (Japan)

2009-02-15

We have measured the radiation transport and dose reduction properties of lunar soil with respect to selected heavy ion beams with charges and energies comparable to some components of the galactic cosmic radiation (GCR), using soil samples returned by the Apollo missions and several types of synthetic soil glasses and lunar soil simulants. The suitability for shielding studies of synthetic soil and soil simulants as surrogates for lunar soil was established, and the energy deposition as a function of depth for a particular heavy ion beam passing through a new type of lunar highland simulant was measured. A fragmentation and energy loss model was used to extend the results over a range of heavy ion charges and energies, including protons at solar particle event (SPE) energies. The measurements and model calculations indicate that a modest amount of lunar soil affords substantial protection against primary GCR nuclei and SPE, with only modest residual dose from surviving charged fragments of the heavy beams.

Integrated lunar materials manufacturing process