Synthesis of calculational methods for the design and analysis of radiation shields for nuclear rocket systems. Volume 8 - DAFT, ODD-K angular flux tapes program Final progress report

ODD-K angular flux tape computer program for radiation shielding design and analysis in nuclear rocket system

Synthesis of calculational methods for the design and analysis of radiation shields for nuclear rocket systems. Volume 7 - NAGS, a Fortran 4 data processing program for calculation of neutron and gamma ray sources and neutron and gamma ray heating in two dimensional geometries Final progress report

Neutron flux and gamma ray source edit computer program for design and analysis of radiation shields in nuclear rocket system

Synthesis of calculational methods for the design and analysis of radiation shields for nuclear rocket systems. Volume 2 - Analysis of radiation measurements in a nuclear rocket propellant tank mockup using simulated liquid hydrogen

Calculational methods for nuclear rocket radiation shield design - analysis of radiation measurements in nuclear rocket propellant tank mockup using simulated liquid hydroge

Nuclear rocket shielding methods, modification, updating, and input data preparation. Volume 5 - Two-dimensional, discrete ordinates transport technique Final progress report

Two dimensional, discrete ordinates transport technique for use with nuclear rocket shielding methods, modification, updating, and data input preparation - Vol.

Nuclear rocket shielding methods, modification, updating, and input data preparation. Volume 1 - Synopsis of methods and results of analysis Final progress report

Analysis of data systems and computer programs for nuclear rocket shielding methods, modification, updating, and data input preparation - Vol.

Nondestructive Analysis of Astromaterials by Micro-CT and Micro-XRF Analysis for PET Examination

An integral part of any sample return mission is the initial description and classification of returned samples by the preliminary examination team (PET). The goal of the PET is to characterize and classify returned samples and make this information available to the larger research community who then conduct more in-depth studies on the samples. The PET tries to minimize the impact their work has on the sample suite, which has in the past limited the PET work to largely visual, nonquantitative measurements (e.g., optical microscopy). More modern techniques can also be utilized by a PET to nondestructively characterize astromaterials in much more rigorous way. Here we discuss our recent investigations into the applications of micro-CT and micro-XRF analyses with Apollo samples and ANSMET meteorites and assess the usefulness of these techniques in future PET. Results: The application of micro computerized tomography (micro-CT) to astromaterials is not a new concept. The technique involves scanning samples with high-energy x-rays and constructing 3-dimensional images of the density of materials within the sample. The technique can routinely measure large samples (up to approx. 2700 cu cm) with a small individual voxel size (approx. 30 cu m), and has the sensitivity to distinguish the major rock forming minerals and identify clast populations within brecciated samples. We have recently run a test sample of a terrestrial breccia with a carbonate matrix and multiple igneous clast lithologies. The test results are promising and we will soon analyze a approx. 600 g piece of Apollo sample 14321 to map out the clast population within the sample. Benchtop micro x-ray fluorescence (micro-XRF) instruments can rapidly scan large areas (approx. 100 sq cm) with a small pixel size (approx. 25 microns) and measure the (semi) quantitative composition of largely unprepared surfaces for all elements between Be and U, often with sensitivity on the order of a approx. 100 ppm. Our recent testing of meteorite and Apollo samples on micro-XRF instruments has shown that they can easily detect small zircons and phosphates (approx. 10 m), distinguish different clast lithologies within breccias, and identify different lithologies within small rock fragments (2-4 mm soil Apollo soil fragments)

Diffuse flow environments within basalt- and sediment-based hydrothermal vent ecosystems harbor specialized microbial communities

Hydrothermal vents differ both in surface input and subsurface geochemistry. The effects of these differences on their microbial communities are not clear. Here, we investigated both alpha and beta diversity of diffuse flow-associated microbial communities emanating from vents at a basalt-based hydrothermal system along the East Pacific Rise (EPR) and a sediment-based hydrothermal system, Guaymas Basin. Both Bacteria and Archaea were targeted using high throughput 16S rRNA gene pyrosequencing analyses. A unique aspect of this study was the use of a universal set of 16S rRNA gene primers to characterize total and diffuse flow-specific microbial communities from varied deep-sea hydrothermal environments. Both surrounding seawater and diffuse flow water samples contained large numbers of Marine Group I (MGI) Thaumarchaea and Gammaproteobacteria taxa previously observed in deep-sea systems. However, these taxa were geographically distinct and segregated according to type of spreading center. Diffuse flow microbial community profiles were highly differentiated. In particular, EPR dominant diffuse flow taxa were most closely associated with chemolithoautotrophs, and off axis water was dominated by heterotrophic-related taxa, whereas the opposite was true for Guaymas Basin. The diversity and richness of diffuse flow-specific microbial communities were strongly correlated to the relative abundance of Epsilonproteobacteria, proximity to macrofauna, and hydrothermal system type. Archaeal diversity was higher than or equivalent to bacterial diversity in about one third of the samples. Most diffuse flow-specific communities were dominated by OTUs associated with Epsilonproteobacteria, but many of the Guaymas Basin diffuse flow samples were dominated by either OTUs within the Planctomycetes or hyperthermophilic Archaea. This study emphasizes the unique microbial communities associated with geochemically and geographically distinct hydrothermal diffuse flow environments

Identification of New Lithic Clasts in Lunar Breccia 14305 by Micro-CT and Micro-XRF Analysis

From 1969 to 1972, Apollo astronauts collected 382 kg of rocks, soils, and core samples from six locations on the surface of the Moon. The samples were initially characterized, largely by binocular examination, in a custom-built facility at Johnson Space Center (JSC), and the samples have been curated at JSC ever since. Despite over 40 years of study, demand for samples remains high (~500 subsamples per year are allocated to scientists around the world), particularly for plutonic (e.g., anorthosites, norites, etc.) and evolved (e.g., granites, KREEP basalts) lithologies. The reason for the prolonged interest is that as new scientists and new techniques examine the samples, our understanding of how the Moon, Earth, and other inner Solar System bodies formed and evolved continues to grow. Scientists continually clamor for new samples to test their emerging hypotheses. Although all of the large Apollo samples that are igneous rocks have been classified, many Apollo samples are complex polymict breccias that have previously yielded large (cm-sized) igneous clasts. In this work we present the initial efforts to use the non-destructive techniques of micro-computed tomography (micro-CT) and micro x-ray fluorescence (micro-XRF) to identify large lithic clasts in Apollo 14 polymict breccia sample 14305. The sample in this study is 14305,483, a 150 g slab of regolith breccia 14305 measuring 10x6x2 cm (Figure 1a). The sample was scanned at the University of Texas High-Resolution X-ray CT Facility on an Xradia MicroXCT scanner. Two adjacent overlapping volumes were acquired at 49.2 micrometer resolution and stitched together, resulting in 1766 slices. Each volume was acquired at 100 kV accelerating voltage and 98 mA beam current with a 1 mm CaF2 filter, with 2161 views gathered over 360deg at 3 seconds acquisition time per view. Micro-XRF analyses were done at Washington University in St. Louis, Missouri on an EDAX Orbis PC micro-XRF instrument. Multiple scans were made at 40 kV accelerating voltage, 800 mA beam current, 30 m beam diameter, and a beam spacing of 30-120 micrometer. The micro-CT scan of 14305,483 (Figure 2) was able to identify several large lithic clasts (approx. 1 cm) within the interior of the slab. These clasts will be exposed by band-sawing or chipping of the slab, and their composition more fully characterized by subsequent micro-XRF analysis. In addition to lithic clasts, the micro-CT scans identified numerous mineral clasts, including many FeNi metal grains, as well as the prominent fractures within the slab. The micro-XRF analyses (Figure 1b,c) of the slab surfaces revealed the bulk chemical compositions (qualitative) of the different clast types observed. In particular, by looking at the ratios of major elements (e.g. Ca:Mg:Fe), differences among the many observed clast types are readily observed. Moreover, several clasts not apparent to the naked eye were revealed in the K:Al:Si ratio map. The scans are also able to identify small grains of Zr- and P-rich minerals (not shown), which could in turn yield important age dates for the samples

Nuclear rocket shielding methods, modification, updating, and input data preparation. Volume 3 - Cross section generation and data processing techniques Final progress report

Cross section generation and data processing techniques for nuclear rocket shielding methods, modification, updating, and input data preparation - Vol.

Artemis Curation: Preparing for Sample Return from the Lunar South Pole

Space Policy Directive-1 mandates that 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 addition, the Vice President stated that It is the stated policy of this administration and the United States of America to return American astronauts to the Moon within the next five years, that is, by 2024. These efforts, under the umbrella of the recently formed Artemis Program, include such historic goals as the flight of the first woman to the Moon and the exploration of the lunar south-polar region. Among the top priorities of the Artemis Program is the return of a suite of geologic samples, providing new and significant opportunities for progressing lunar science and human exploration. In particular, successful sample return is necessary for understanding the history of volatiles in the Solar System and the evolution of the Earth-Moon system, fully constraining the hazards of the lunar polar environment for astronauts, and providing the necessary data for constraining the abundance and distribution of resources for in-situ resource utilization (ISRU). Here we summarize the ef-forts of the Astromaterials Acquisition and Curation Office (hereafter referred to as the Curation Office) to ensure the success of Artemis sample return (per NASA Policy Directive (NPD) 7100.10E)