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

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All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

An Experimental Study on Low Pressure Frost Formation for Lunar Polar Water Capture

In-situ resource utilization (ISRU) is a vital component of NASA’s mission to the Moon and beyond, as the extraction of resources from the environment can reduce payload weight and the frequency of resupply missions. Since the discovery of water in the regolith of the permanently shadowed regions (PSR) of the Moon, its extraction and transport has become an area of increasing interest for NASA. One proposed method is heating icy regolith to free the water before desublimating and transporting it as ice in a tanker. However, little is known regarding the dynamics of frost growth at low pressures, and an understanding of the heat transfer process is required to properly size the heat exchanger for the tanker. To investigate this phenomenon, a cold plate was placed in a vacuum chamber with water vapor directed at its surface. The chamber pressure (300 and 500 Pa) and cold plate temperature (–18 to –5 °C) were kept below the triple point and varied throughout the experiment to examine their impact on frost layer heat transfer. As water flowed into the chamber and deposited on the cold plate surface, the heat flux and temperature were measured along with the frost layer thickness and/or mass. Density calculated at the conclusion of each test suggests the frost layer is denser than that of frost grown at atmospheric pressure. The results demonstrate unexpected density and heat transfer characteristics and require development of a new model of frost growth for lunar conditions.

In situ Resource Utiliztion↗
NASA NTRSDate not supplied

An Experimental Study on Low Pressure Frost Formation for Lunar Polar Water Capture

In-situ resource utilization (ISRU) is a vital component of NASA’s mission to the Moon and beyond, as the extraction of resources from the environment can reduce payload weight and the frequency of resupply missions. Since the discovery of water in the regolith of the permanently shadowed regions (PSR) of the Moon, its extraction and transport has become an area of increasing interest for NASA. One proposed method is heating icy regolith to free the water before de-sublimating and transporting it as ice in a tanker. However, little is known regarding the dynamics of frost growth at low pressures, and an understanding of the heat transfer process is required to properly size the heat exchanger for the tanker. To investigate this phenomenon, a cold plate was placed in a vacuum chamber with water vapor directed at its surface. The chamber pressure (300 and 500 Pa) and cold plate temperature (–18 to –5 °C) were kept below the triple point and varied throughout the experiment to examine their impact on frost layer heat transfer. As water flowed into the chamber and deposited on the cold plate surface, the heat flux and temperature were measured along with the frost layer thickness and/or mass. Density calculated at the conclusion of each test suggests the frost layer is denser than that of frost grown at atmospheric pressure. The results demonstrate unexpected density and heat transfer characteristics and require development of a new model of frost growth for lunar conditions

Lunar polar↗
NASA NTRS2019

Incorporation of Functionalized Polyhedral Oligomeric Silsesquioxane Nanomaterials as Reinforcing Agents for Impact Ice Mitigating Coatings

In-flight, aircraft are exposed to a wide range of environments. One commonly exposed environment are clouds containing super-cooled water droplets. These water drop- lets exist in a metastable state below the freezing point of water, in the range of 0 to -20°C. As the vehicle impacts the droplets, latent heat is released and within milliseconds the droplets convert to ice. This process is referred to as impact icing or in-flight icing.1 Impact icing is a major concern for aircraft since it can lead to degraded aerodynamic performance and, if left un- treated, can lead to loss of the vehicle. Active approaches (i.e., pneumatic boots, heated air ducts) typically utilized in mitigating in-flight ice accretion significantly increases vehicle weight and cannot be applied to all aircraft.1-3 A passive approach based on coatings is desired, but durability issues are a concern, especially on the wing leading edge.3 Nanomaterials have been shown to afford significant improvement in coating and composite physical properties at low loading levels.4 In this study, Polyhedral Oligomeric Silsesquioxane (POSS) nanomaterials have been shown to increase coating durability. Also, with wide variety of functionalities present on the arm structure, POSS nanomaterials have been shown to readily alter coating surface chemistry to mitigate impact ice adhesion from -16 to -8°C in a simulated in-flight icing environment.

Beck, Devon M.↗
NASA NTRS1996

X-Ray Imaging Study

The space environment in which the Space Station Freedom and other space platforms will orbit is truly a hostile environment. For example, the currently estimated integral fluence for electrons above 1 Mev at 2000 nautical miles is above 2 x 1O(exp 10) electrons/sq cm/day and the proton integral fluence is above 1 x 10(exp 9) protons/sq cm/day. At the 200 - 400 nautical miles, which is more representative of the altitude which will provide the environment for the Space Station, each of these fluences will be proportionally less; however, the data indicates that the radiation environment will obviously have an effect on structural materials exposed to the environment for long durations. The effects of this combined environment is the issue which needs to be understood for the long term exposure of structures in space. At the same time, there will be substantial potential for collisions between the space platforms and space debris. The current NASA catalogue contains over 4500 objects floating in space which are not considered payloads. This debris can have significant effects on collision with orbiting spacecraft. In order to better understand the effect of these hostile phenomena on spacecraft, several types of studies are being performed to simulate at some level the effect of the environment. In particular the study of debris clouds produced by hypervelocity impact on the various surfaces anticipated on the Space Station is very important at this point in time. The need to assess the threat of such debris clouds on space structures is an on-going activity. The Space Debris Impact facility in Building 4612 provides a test facility to monitor the types of damage produced with hypervelocity impact. These facilities are used to simulate space environmental effects from energetic particles. Flash radiography or x-ray imaging has traditionally provided such information and as such has been an important tool for recording damage in situ with the event. The proper operation of the system can provide much useful information with respect to parametric analysis of the hypervelocity experiment. The following report outlines the procedures developed to optimize the operation of the x-ray imaging system and its operational characteristics.

OBrien, Susan K.↗
NASA NTRS2010

Target and Projectile: Material Effects on Crater Excavation and Growth

Scaling relationships allow the initial conditions of an impact to be related to the excavation flow and final crater size and have proven useful in understanding the various processes that lead to the formation of a planetary-scale crater. In addition, they can be examined and tested through laboratory experiments in which the initial conditions of the impact are known and ejecta kinematics and final crater morphometry are measured directly. Current scaling relationships are based on a point-source assumption and treat the target material as a continuous medium; however, in planetary-scale impacts, this may not always be the case. Fragments buried in a megaregolith, for instance, could easily approach or exceed the dimensions of the impactor; rubble-pile asteroids could present similar, if not greater, structural complexity. Experiments allow exploration into the effects of target material properties and projectile deformation style on crater excavation and dimensions. This contribution examines two of these properties: (1) the deformation style of the projectile, ductile (aluminum) or brittle (soda-lime glass) and (2) the grain size of the target material, 0.5-1 mm vs. 1-3 mm sand.

Anderson, J. L. B.↗
DOE OSTI2024

Grain boundary self-diffusion and point defect interactions in α -U via molecular dynamics

Though metallic U-Zr fuel has been used in nuclear reactors since the 1960s, many of its fundamental and thermodynamic properties are still unknown. The a-U phase, which has a highly anisotropic crystal structure and physical properties, is present in U-Zr fuel. The character and behavior of a-U grain boundaries will strongly impact fuel thermophysical performance under irradiation. Here, we study the interaction of point defects with grain boundaries, diffusion along grain boundaries, and the predicted diffusional creep behavior of a-U via molecular dynamics. We calculate the segregation energy of vacancies and interstitials to grain boundaries and quantify the biased sink strength of the grain boundaries, and observe that this sink strength is not strongly dependent on the grain boundary orientation. We also find that grain boundary diffusivity is strongly dependent on the grain boundary energy and grain boundary orientation. The presence of point defects within the grain boundary can induce diffusion in grain boundaries with low formation energies and can enhance diffusion in high-energy grain boundaries. We also find that diffusional creep of a-U at prototypical metallic fuel operation conditions is extremely high and could help explain observed metallic fuel swelling behaviors.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
NASA NTRS1983

Deep space optical communications experiment

An optical communications experiment between a deep space vehicle and an earth terminal is under consideration for later in this decade. The experimental link would be incoherent (direct detection) and would employ two-way cooperative pointing. The deep space optical transceiver would ride piggyback on a spacecraft with an independent scientific objective. Thus, this optical transceiver is being designed for minimum spacecraft impact - specifically, low mass and low power. The choices of laser transmitter, coding/modulation scheme, and pointing mechanization are discussed. A representative telemetry link budget is presented.

Kinman, P.↗
NASA NTRS2016

Similar Estimates of Temperature Impacts on Global Wheat Yield by Three Independent Methods

The potential impact of global temperature change on global crop yield has recently been assessed with different methods. Here we show that grid-based and point-based simulations and statistical regressions (from historic records), without deliberate adaptation or CO2 fertilization effects, produce similar estimates of temperature impact on wheat yields at global and national scales. With a 1 C global temperature increase, global wheat yield is projected to decline between 4.1% and 6.4%. Projected relative temperature impacts from different methods were similar for major wheat-producing countries China, India, USA and France, but less so for Russia. Point-based and grid-based simulations, and to some extent the statistical regressions, were consistent in projecting that warmer regions are likely to suffer more yield loss with increasing temperature than cooler regions. By forming a multi-method ensemble, it was possible to quantify 'method uncertainty' in addition to model uncertainty. This significantly improves confidence in estimates of climate impacts on global food security.

Climate impacts↗
DOE OSTI2025

Generalizing the compressible pairwise interaction extended point-particle model

Ejecta physics plays an important role in material interfaces that are impacted by a strong shock wave. When a shock impacts a rough surface of solid material and melts it, the Richtmyer–Meshkov instability grows perturbations on the surface, which can eject particles. After release, the ejecta travel through the post-shock compressible flow. To accurately simulate a large number of ejecta particles, an Euler–Lagrange approach is preferred, which requires modeling the subgrid-scale physics involved with fluid–particle interactions. We generalize the previous work from Hsiao et al. (2023) to consider systems of moving particles subject to any loading shock. The following improvements were made: (1) Particles are allowed to move relative to each other (2) Non-planar shocks are accounted for along with allowing for variable shock speeds. As a result, the generalized algorithm was tested with particle-resolved simulations for canonical test cases. The results of these tests are discussed and analyzed.

97 MATHEMATICS AND COMPUTING↗
NASA NTRS1989

Transient dynamic analysis of laminated composite plates subjected to transverse impact

The dynamic response of a composite laminate plate to transverse impact loading is simulated numerically. An FEM scheme based on an eight-point brick element and three-dimensional linear elasticity theory is employed, assuming that the laminate layers are homogeneous and orthotropic. The derivation of the model is given in detail; the numerical implementation is briefly outlined; and results for the impact of 0.5-inch-diameter Al spheres at 500, 1000, and 1500 inch/sec on clamped or simply supported 3 x 3-inch plates made of T300/934 graphite/epoxy prepreg with ply orientation (0/-45/45/90)2S are presented in extensive graphs. The model is shown to provide accurate information on the histories of impactor-plate contact force; impactor displacement and velocity; and displacement, velocity, strain, and stress throughout the plate.

Wu, Hsi-Yung T.↗
NASA NTRS1993

Research program on the Manson impact structure, Iowa

At or near the end of the Cretaceous, at least two large impact events occurred in the western hemisphere. One impact formed the 180-km diameter Chicxulub crater on the northern tip of the Yucatan peninsula. Another formed the 35-km diameter Manson structure in western Iowa. Several lines of evidence, including the chemical and isotopic composition of glass found in the K/T boundary layer at sites in the Gulf of Mexico and Caribbean region, the regional variation in thickness and the size of spherules in the K/T boundary layer, and indications at and near the boundary of disturbance and deposition of beds by giant waves in the Gulf of Mexico, point to Chicxulub as a major source of K/T boundary material, including a lower layer of clay at K/T boundary sites in western North America. The size, abundance, and mineral and lithic composition of shocked grains from an upper K/T boundary layer found at western North American sites, on the other hand, point to Manson as a possible source crater. More than one impact seems to be indicated by the K/T boundary stratigraphy in western North America, and present constraints on the age of the Manson structure suggest that it, as well as Chicxulub, may be a K/T boundary crater. Multiple craters produced over a relatively short interval of time are much more likely to have been formed by impact of comets rather than by impact of asteroids. Among likely mechanisms that could have produced multiple craters at or near the time of the K/T boundary are as follows: (1) splitting of a comet shortly before impact with Earth (impacts may have been spaced over about an hour), (2) fragmentation of a very large, Sun-grazing, periodic comet to form a compact stream of comets that intercepted the Earth's orbit (impacts may have been spread over about a century), and (3) perturbation of the Oort comet cloud by a passing massive object to form a comet shower in the inner solar system (impacts may have been spread over about a million years). Only in the first two cases are the impacts likely to have been close enough in time to contribute to the observed K/T boundary layers. All mechanisms could have produced many more than two craters.

Shoemaker, E. M.↗
NASA NTRS2023

A Single-Point Modeling Approach for the Intercomparison and Evaluation of Ozone Dry Deposition Across Chemical Transport Models (Activity 2 of AQMEII4)

A primary sink of air pollutants and their precursors is dry deposition. Dry deposition estimates differ across chemical transport models, yet an understanding of the model spread is incomplete. Here, we introduce Activity 2 of the Air Quality Model Evaluation International Initiative Phase 4 (AQMEII4). We examine 18 dry deposition schemes from regional and global chemical transport models as well as standalone models used for impact assessments or process understanding. We configure the schemes as single-point models at eight Northern Hemisphere locations with observed ozone fluxes. Single-point models are driven by a common set of site-specific meteorological and environmental conditions. Five of eight sites have at least 3 years and up to 12 years of ozone fluxes. The interquartile range across models in multiyear mean ozone deposition velocities ranges from a factor of 1.2 to 1.9 annually across sites and tends to be highest during winter compared with summer. No model is within 50 % of observed multiyear averages across all sites and seasons, but some models perform well for some sites and seasons. For the first time, we demonstrate how contributions from depositional pathways vary across models. Models can disagree with respect to relative contributions from the pathways, even when they predict similar deposition velocities, or agree with respect to the relative contributions but predict different deposition velocities. Both stomatal and nonstomatal uptake contribute to the large model spread across sites. Our findings are the beginning of results from AQMEII4 Activity 2, which brings scientists who model air quality and dry deposition together with scientists who measure ozone fluxes to evaluate and improve dry deposition schemes in the chemical transport models used for research, planning, and regulatory purposes.

Dry deposition↗
DOE OSTI2025

A Bayesian Framework for Spectral Reprojection

Abstract Fourier partial sum approximations yield exponential accuracy for smooth and periodic functions, but produce the infamous Gibbs phenomenon for non-periodic ones. Spectral reprojection resolves the Gibbs phenomenon by projecting the Fourier partial sum onto a Gibbs complementary basis, often prescribed as the Gegenbauer polynomials. Noise in the Fourier data and the Runge phenomenon both degrade the quality of the Gegenbauer reconstruction solution, however. Motivated by its theoretical convergence properties, this paper proposes a new Bayesian framework for spectral reprojection, which allows a greater understanding of the impact of noise on the reprojection method from a statistical point of view. We are also able to improve the robustness with respect to the Gegenbauer polynomials parameters. Finally, the framework provides a mechanism to quantify the uncertainty of the solution estimate.

Li, Tongtong (ORCID:0000000276644764)↗
DOE OSTI2024

Measuring differential particle correlations in relativistic nuclear collisions

This study explores the transverse momentum ( p T ) dependencies of symmetric and asymmetric correlations (SC and ASC) with one and two particles of interest in Au + Au collisions at 200 GeV. Leveraging a multiphase transport (AMPT) model, the investigation delves into the sensitivity of these correlations to the final state effects, providing valuable insights into their potential for constraining the final state effects' p T dependencies. The HIJING model is employed as a benchmark for nonflow correlations, shedding light on their impact on interpreting SC and ASC data. Moreover, the study points out that differential SC and ASC with one and two particles of interest (POIs) typically incorporate contributions from event-plane angle fluctuations. Consequently, this work highlights the significance of SC and ASC with one and two POIs as valuable tools for investigating the p T nature of the final state effects and advocates for comprehensive experimental measurements across various beam energies and system sizes to enhance understanding and provide additional constraints for theoretical models. Published by the American Physical Society 2024

Physics↗
DOE OSTI2025

Videos, photos, and AI-derived grain size data associated with “High-throughput AI Video Surveys Enable Reproducible Multiscale Sediment Size Mapping, with Implications for Hydrobiogeochemical Parameterization”

NOTE: The manuscript associated with this data package is currently in review. The data may be revised based on reviewer feedback. Upon manuscript acceptance, this data package will be updated with the final dataset and additional metadata. This data package is associated with the manuscript “High-throughput AI Video Surveys Enable Reproducible Multiscale Sediment Size Mapping, with Implications for Hydrobiogeochemical Parameterization” under review. This data package includes five data types: 1) raw photos and videos from drone survey and walking smartphone surveys; 2) images derived from raw videos; 3) manual labeling of reference scales; 4) metadata for all images and photo resolution derived from artificial intelligence (AI) models or manual labels, 5) grain size data obtained from AI models for all photos, 6) metadata and grain size data after quality control, 7) summaries of sample efficiency for all data, and 8) computational fluid dynamics (CFD) data used to support hydro-biogeochemical (HBGC) parameter estimation. Such data is used to 1) demonstrate significant improvements in accuracy, efficiency, and quality control for grain size data collection with the help of AI models, 2) study the spatial heterogeneity of grain size and observation reproducibility based on tens of thousands of data points generated by the AI models, and 3) evaluate the impacts of grain size heterogeneity on key HBGC parameters across sediment-to-reach and hourly-to-yearly scales. In particular, the data package contains 116 folders and 179696 files. The files include 41 videos in .mov format, 64047 photos in .jpg format, 13541 video-derived photos in .png format, 12747 segmentation mask data in .tif format, 12747 segmentation data in .json format, 24771 .csv files that with metadata and grain size for each individual photo as well as water depth and velocity data from CFD and observation, 51791 .txt files of raw AI predicted labels, and 11 flight record data in .srt format. The summary for all metadata and grain size statistics information is included in “Scales_V3_NG.csv” and “Statistics_V3_NG.csv”. The summary for data that pass data quality control (QC) level 0-2 is included in “QCStatistics_V3_NG.csv”. The QC level 0 represents photos whose photo resolution is positive, excluding photos that miss reference scale. The QC level 1 means reference scale circularity uncertainty is less than 5% for smartphone images while representing photo resolution is larger than 0.44 mm/pixel for drone images. The QC level 2 means excluding photos whose grain number is less than 100, a minimum number of grains recommended by classic literature. The summary for each video’s name, length, frame rates, survey area, grain number, survey efficiency, etc. can be found in “QCSummary_V3_NG.csv”. The summary for site name, GPS coordinates, and number of images at each site can be found in “SitesSummary_V3_*.csv” files. Overall computational efficiency summary is reported in Table 4 of accompanying manuscript. Additionally, the nitrate concentration data used in this work was downloaded from an existing dataset published on ESS-DIVE (Boat-Dragged Sensor Hanford Reach.csv; Conner A. et al., 2020). We thank the United States Forest Service, Washington Department of Fish and Wildlife, Washington Department of Natural Resources, Cowiche Canyon Conservatory, Port of Benton, and the Confederated Tribes and Bands of the Yakama Nation for access to field locations where the data were collected. We also thank the Yakama Nation Tribal Council and Yakama Nation Fisheries for working with us to facilitate data collection and optimization of data usage according to their values and worldview.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

First Observation of Neutrino Candidates in ProtoDUNE

The Neutrino Platform at CERN hosts two massive prototypes for the DUNE Far Detector to test the technology for the coming Horizontal Drift and Vertical Drift designs, almost perfectly on axis with the direction of the SPS beamline pointed towards the North Area. The 400 GeV/c SPS protons impacting on the T2 target area may produce exotic particles that could travel ~700 meters to the detectors, in addition to a substantial flux of neutrinos. Simulations of the neutrino flux demonstrate that thousands of neutrino interactions are expected per week in the active volume of NP04 spanning energies from a few GeV up to 180 GeV, constituting the main background for such search. The first step towards establishing a BSM physics program at the Neutrino Platform is therefore to observe neutrinos originating from the SPS beam. A sample of high-energy neutrino events in a DUNE FD-like LArTPC may also be of broader use to the DUNE collaboration. For example, by testing the performance of reconstruction algorithms on highly-energetic neutrino interactions with large hadronic showers. An initial neutrino search was performed by developing filters to remove cosmic events. After filtering, the remaining events were eye-scanned to identify neutrino candidates amongst the residual cosmic background. Over two of the available NP04 runs, 29 neutrino candidates were identified. A separate run taken with the SPS beam off yielded no neutrino candidates. An analysis is now under development that will use all available data, large Monte Carlo samples and full event reconstruction, with the aim of confirming whether NP04 is capable of observing feebly interacting particles originating from the SPS beam.

Pullia, Dario [CERN]↗
NASA NTRS1972

Measurements of O(1 D) quenching rates in the F-region

In-situ determinations of the quenching of O(1 D) atoms by N2 and O2 molecules were made from observations of 6300 A nightglow intensity enhancements produced by the Platteville 1.6 MW transmitter. The heating of F-region electrons near the point of reflection of the RF wave leads to electron impact excitation of oxygen atoms to the O(1 D) state. It is shown that the resulting region of enhance 6300 A emission is localized to the region of electron energy absorption for heating at the lower altitudes. At 225 km the measured time constants for intensity buildup following transmitter turn-on and for intensity decay following turn-off are identical and equal to (13 plus or minus 1) sec. Time constants varying from 30 to 80 sec are found for the altitude range 260 to 300 km. The inferred quenching coefficient for the whole altitude range, 225 to 300 km, is 4.4 + 2 or - 1 x 10 to the minus 11th power cu cm/sec at 950 K, in good agreement with laboratory data. The quenching frequency obtained at 225 km, when referred to the altitude 120 km, is equal to (21 plus or minus 2)/sec, in agreement with less direct ionospheric determinations.

Sipler, D. P.↗
NASA NTRS1979

Cost-effective technology advancement directions for electric propulsion transportation systems in earth-orbital missions

The directions that electric propulsion technology should take to meet the primary propulsion requirements for earth-orbital missions in the most cost effective manner are determined. The mission set requirements, state of the art electric propulsion technology and the baseline system characterized by it, adequacy of the baseline system to meet the mission set requirements, cost optimum electric propulsion system characteristics for the mission set, and sensitivities of mission costs and design points to system level electric propulsion parameters are discussed. The impact on overall costs than specific masses or costs of propulsion and power systems is evaluated.

Regetz, J. D., Jr.↗