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

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At least 1,189 records · Page 66
All sourcesNASA NTRSDOE OSTI
NASA NTRS2019

Model Based Engineering for Software Assurance

NASA's successful development of next generation space vehicles, habitats, and robotic systems will require reliable hardware and software systems. The aim of this initiative is to develop modeling methodology and tools to support Model-Based Systems Engineering (MBSE) for software assurance and reliability analysis. This effort expands the Unified Modeling Language (UML) software design models to include fault data for the extraction of Failure Modes and Effects Criticality Analysis (FMECA) and Fault Tree Analysis (FTA) for software. We explored different modeling approaches to integrate the UML software design models with the Systems Modeling Language (SysML) system models to generate an integrated model and reliability tools that take into account software and hardware interfaces.The benefits of this concept directly affect the safety community with quick turnarounds to produce software assurance and reliability analysis artifacts and the ability to visualize failure effects, both hardware and software. The result is enhanced system design integrity and early identification of system risks. This initiative will enable software assurance activities early in the system design lifecycle, facilitating the discovery of design weaknesses and enhancing the capability to produce safe, hazard-free systems

Wang, Lui↗
NASA NTRS2016

Mars 2020 Coring Drill: Prototype Testing and Analysis

The Mars 2020 rover will carry a new subsystem to collect and prepare Martian rocks and regolith (loose, unconsolidated) samples. This includes a rotary percussive coring drill and a set of sample tubes. About 30 of these sample tubes will be deposited at select locations for return on a potential future sample-retrieval mission. In laboratories on Earth, specimens from Mars could be analyzed for evidence of past life on Mars and possible health hazards for future human missions. Hardware and control algorithms for the coring drill are based heavily on testing. Results from testing of prototype hardware are used to refine the design

Kreichbaum, Kristopher↗
DOE OSTI2023

Effect of feed composition on the production of off-gases during vitrification of simulated low-activity nuclear waste

During the vitrification of nuclear waste, hazardous and radioactive emissions are generated from the feed-to-glass conversion reactions, in addition to discharges from forced air bubbling and air inleakage. Although the major gaseous emissions are water vapor, nitrogen, and carbon dioxide, various monitored environmental pollutants are also released, such as nitrogen oxides or sulfur dioxide. In addition, reactions between organics and nitrates in the feed may also form products of incomplete combustion such as carbon monoxide and acetonitrile. Although off-gas emissions are commonly measured during both laboratory- and pilot-scale melter testing, no predictive tool is currently available to a priori estimate the composition of gaseous emissions during nuclear waste vitrification. This work forms a basis for the development of such predictive tool by measuring gas evolution from a broad range of simulated low-activity waste melter feeds using evolved gas analysis data and developing correlations between the feed and off-gas compositions. Using reaction stoichiometry and regression analysis, we demonstrate that next to the content of nitrogen and organic carbon in the feed, the gaseous emissions are affected by the feed reduction-oxidation conditions – the more the feed is reduced, the less nitrogen monoxide, and more carbon monoxide and acetonitrile evolves. In conclusion, the results presented in this work provide a first step towards reducing the amount of expensive physical melter testing and the regression analysis provides a simple tool for rapid optimization of feed composition with respect to off-gas composition.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2025

Mechanically induced thermal runaway severity analysis of Li-ion batteries and continuous energy release monitoring

The large-scale deployment of Li-ion batteries in stationary energy storage and electrical vehicle applications demands a strong focus on safety, particularly on the thermal runaway risk and severity evaluation. A standardized single-side mechanical indentation test protocol was developed to induce an internal short-circuit (ISC) and evaluate cells' thermal runaway severity at different state of charge (SOC). The observed hazard severity (OHS in five categories) and evaluated scores in this work have a comprehensive consideration of each cell's capacity, initial voltage, SOC, temperature and voltage change, allowing a better evaluation of the cells' thermal runaway potential. This method was applied to about 200 Li-ion batteries in order to build an extensive thermal runaway database covering various SOCs, capacities and chemistries. In this study, we monitored the transitions of stored electrochemical energy and applied mechanical energy into both thermal energy and acoustic emissions (AE). The surface temperature and mechanical failures were monitored by infrared imaging and AE to capture critical events within battery cells throughout the mechanical indentation tests. Furthermore, the initial temperature maps can predict two types of follow-up events: thermal runaway or gradual heat release via conduction. Analyzing each cell's severity, AEs, and leveraging the evolving database offer insights into predicting occurrences of thermal runaway. The test method, thermal runaway severity evaluation and prediction, and the corresponding database provide battery designers, manufacturers, and end-users a clear overview of Li-ion batteries' thermal runaway potential under mechanical abuse, advancing the safety design of Li-ion batteries.

Acoustic emission↗
NASA NTRS2010

Analysis of a Hypergolic Propellant Explosion During Processing of Launch Vehicles in the VAB

NASA is developing launch vehicles to support missions to Low Earth Orbit (LEO), the moon and deep space. Whether manned or unmanned, the vehicle components will likely be integrated in the Vehicle Assembly Building (VAB) at Kennedy Space Center (KSC) and typically include a fueled spacecraft (SC) that sits on top of one or more stages. The processing of a fueled SC involves hazardous operations when it is brought into the VAB Transfer Aisle and lifted a significant height for mating with lower stages. Accidents resulting from these hazardous operations could impact unrelated personnel working in buildings adjacent to the VAB. Safe separation distances based on the DOD Explosives Standards Quantity-Distance (Q-D) approach result in large IBD arcs. This paper presents site-specific air blast and fragmentation hazard analyses for comparison with the Q-D arcs as well as consequence and risk analyses to provide added information for the decision maker. A new physics-based fragmentation model is presented that includes: a) the development of a primary fragment list (which defines the fragment characteristics) associated with a hypergolic propellant explosion, b) a description of a 3D fragment bounce model, c) the results of probabilistic Monte-Carlo simulations (that include uncertainties in the fragment characteristics) to determine: i) the hazardous fragment density distance, ii) the expected number of wall/roof impacts and penetrations to over 40 buildings adjacent to the VAB, and iii) the risk to building occupants.

Chrostowski, Jon D.↗
NASA NTRS1998

Urban Environment Initiative

The Urban Environment Initiative (UEI), has been established as part of a Cooperative Agreement with the National Aeronautics and Space Administration (NASA). The UEI is part of NASA's overall High Performance Computing and Communications (HPCC) and the Information Infrastructure Technology Applications (IITA) programs. The goal of the UEI is to provide public access to Earth Science information and promote its use with a focus on the environment of urban areas. This goal will be accomplished through collaborative efforts of the UEI team with both community-based and local/regional governmental organizations. The UEI team is comprised of four organizations representing private industry, NASA, and universities: Prime Technologies Service Corporation, NASA's Minority University Space Interdisciplinary Network (MU-SPIN) California State University, at Los Angeles, and Central State University (Wilberforce, OH). "Urban Environment" refers to the web of environmental, economic, and social factors that combine to create the urban world in which we live. Examples of these factors are population distribution, neighborhood demographic profiles, economic resources, business activities, location and concentration of environmental hazards and various pollutants, proximity and level of urban services, which form the basis of the urban environment and ultimately affect our lives and experiences. The use of Geographic Information Systems (GIS) and remote sensing allows data to be visualized in the forms of maps and spatial images. The use of these tools allow analysis of information about urban environments. Also included are descriptions of the four query types which will assist in understanding the maps.

Source record↗
NASA NTRS2021

Improving Flood and Drought Management in Agricultural River Basins: An Application to the Mun River Basin in Thailand

Agriculture productivity is regularly affected by floods and droughts, and the severity is likely to increase in the future. Even if significant efforts are spent on water development projects, ineffective project planning often means that they continue to occur or are only partly mitigated, for example, in the Mun River Basin, Thailand, where 1000s of water projects have been implemented. Despite this, the basin regularly experiences floods and droughts. In this study, an analysis of the adverse impacts of basin-scale floods and droughts on rice cultivation in the Mun River Basin is conducted, and an estimation of the coping capacity of existing measures. The results demonstrate that while the total storage capacity of in-situ and ongoing projects would be sufficient to tackle both hazards, it can only be achieved if the projects are effectively utilised. Based on this, proposed solutions for the region include small farm ponds, a subsurface floodwater harvesting system, and oxbow lake reconnections. The suggested measures are practicable, economical, environmentally low-impact, and their implementation (if executed with appropriate care) would reduce flood and drought problems in the basin. Notably, the measures and calculation methods proposed for this basin can also be applied to other crops and regions.

Farm pond↗
NASA NTRSDate not supplied

Plans for NASA Contributions to Position, Navigation, and Timing at the Moon

Dating back to the Apollo missions, navigation in cislunar space has traditionally been performed with radiometric tracking and orbit estimation in Earth-based systems. The selected landing zones for Apollo enabled direct to Earth line of sight. Up to the present day, lunar orbiting science missions continue to rely on Earth sensors and processing. The upcoming Artemis and science missions seek different objectives, including landing and traversing in lunar locations occulted from view by Earth. Sustaining a burgeoning and diverse lunar mission set requires in-situ navigation capabilities that do not rely exclusively on Earth-based tracking and provide accurate and timely position, navigation, and timing (PNT) knowledge defined in a lunar reference system. These missions prefer a seamless transition from Earth-centric to lunar-centric PNT systems to reduce complexity and size, weight, and power (SWaP) on their missions. NASA’s heritage in successful high-altitude Global Navigation Satellite System (GNSS) reception is informing an expanded Space Service Volume to the moon and the development of lower SWaP GNSS receivers for the lunar missions. To overcome the geometric restrictions from GNSS –from both limited Dilution of Precision at the moon and lunar occultation – NASA is pursuing PNT services from the Lunar Communications Relay and Navigation System (LCRNS) as part of the interoperable LunaNet architecture to provide lunar-centric navigation services. For situations that require additional sensors, e.g. hazard detection, NASA’s optical navigation algorithms and close-range topographic sensors combine with observables from LunaNet in autonomous navigation software that brings robustness to the PNT solution. This presentation will provide an overview of NASA’s LCRNS PNT services, high-altitude GNSS and close-range sensors, processing algorithms and performance analysis, as well as efforts underway to define the underpinning Lunar Reference System.

Cheryl J. Gramling↗
NASA NTRS2020

Assessment of Extremes in Global Precipitation Products: How Reliable Are They?

Global gridded precipitation products have proven essential for many applications ranging from hydrological modeling and climate model validation to natural hazard risk assessment. They provide a global picture of how precipitation varies across time and space, specifically in regions where ground-based observations are scarce. While the application of global precipitation products has become widespread, there is limited knowledge on how well these products represent the magnitude and frequency of extreme precipitation—the key features in triggering flood hazards. Here, five global precipitation datasets (MSWEP, CFSR, CPC, PERSIANN-CDR, and WFDEI) are compared to each other and to surface observations. The spatial variability of relatively high precipitation events (tail heaviness) and the resulting discrepancy among datasets in the predicted precipitation return levels were evaluated for the time period 1979–2017. The analysis shows that 1) these products do not provide a consistent representation of the behavior of extremes as quantified by the tail heaviness, 2) there is strong spatial variability in the tail index, 3) the spatial patterns of the tail heaviness generally match the Köppen–Geiger climate classification, and 4) the predicted return levels for 100 and 1000 years differ significantly among the gridded products. More generally, our findings reveal shortcomings of global precipitation products in representing extremes and highlight that there is no single global product that performs best for all regions and climates.

Risk assessment↗
NASA NTRSDate not supplied

Machine Learning for the Validation of Expert-Elicited Causal Risk Diagrams

Exposure to spaceflight poses risk to human health in complex ways. To help manage this risk, the Human Systems Risk Board (HSRB) at the National Aeronautics and Space Administration (NASA) maintains a set of causal diagrams that attempt to explain how spaceflight hazards generate health risks and lead to adverse outcomes both in-mission, immediately post-mission, and over the long term. These causal risk diagrams are formulated as directed acyclic graphs (DAGs) and can function as knowledge graphs of connected risks and outcomes. These DAGs have proven useful for communication, and, through network analysis, have allowed for the identification of structurally important factors in the risk network. However, the utility these DAGs provide is directly proportional to their verisimilitude, making assessment of this trait using empirical data – whether from actual human spaceflight or various spaceflight analogue exposures and model organisms – a high priority. In this research we explore the use of machine learning algorithms to learn DAG structure from empirical data as a means of evaluating human-elicited DAG structures. To do so, we test several different graph structure-learning algorithms on data concerning changes in the bones of rats and mice after exposure to either spaceflight or a spaceflight analogue. We explore potential methods for indexing the similarity between each algorithm’s output DAG with all the others and with that of the expert-elicited DAG. We discuss next steps in this ongoing line of research and open science initiatives underway to complete them.

directed acyclic graphs↗
DOE OSTI2025

Investigation of the iodate sorption mechanism by CoAl LDH through experiments and ab initio molecular dynamics simulations

Radioiodine released during the nuclear-fuel cycle constitutes a persistent radiological hazard. In this study, the IO 3 – uptake mechanism of CoAl LDH was resolved by combining pH-controlled sorption experiments, synchrotron XAFS, and DFT-based AIMD simulations. At pH close to 6, approximately 90% of IO 3 – was removed, and the equilibrium distribution coefficient reached about 1.7 × 10 4 mL g –1 . EXAFS analysis indicated an average iodine–oxygen bond length of 1.81 Å and a coordination number near 3, with the fit R-factor equal to 0.002. The simulations faithfully reproduced the experimental spectrum and revealed transient proton hopping events that generated metastable I–O–H species inside the interlayer, thereby confirming nitrate-to-iodate exchange as the controlling capture pathway. Atomic density profiles and radial distribution functions further showed that IO 3 – adopt an end-on orientation perpendicular to the hydroxide sheets, while water molecules mediate proton migration without disturbing the host lattice. In conclusion, the integrated experimental–computational evidence demonstrates that CoAl LDH can rapidly and selectively sequester IO 3 – under near-neutral conditions, offering atomic scale guidance for the rational engineering of layered sorbents for advanced radioactive-waste treatment.

Kang, Jaehyuk [Jeju National Univ. (Korea, Republi↗
DOE OSTI2025

Characterizing How Meteorological Forcing Selection and Parameter Uncertainty Influence Community Land Model Version 5 Hydrological Applications in the United States

Despite the increasing use of large-scale Land Surface Models (LSMs) in predicting hydrological responses in extreme conditions, there's a critical gap in understanding the uncertainties in these predictions. This study addresses this gap through a detailed diagnostic evaluation of the uncertainties arising from meteorological forcing selection and model parametrization in hydrological simulations of the Community Land Model version 5 (CLM5). CLM5 is configured at a spatial scale of about 12-km to simulate runoff processes for 464 headwater watersheds, selected from the Catchment Attributes for Large-Sample Studies (CAMELS) dataset to be representative of physiographic and climatic gradients across the conterminous United States. For each watershed, CLM5 is driven by five commonly used gridded forcing datasets in combination with a large ensemble (> 1200) of key CLM5 hydrologic parameters. Our results suggest that uncertainty in CLM5 runoff simulations resulting from both forcing and parametric sources is markedly higher in arid regions, e.g., Great Plains and Midwest regions. Uncertainty in low flow is dominated by parametric uncertainty, while the selection of meteorological forcing contributes more dominantly to high flow and seasonal flows during fall and spring. Our analysis also demonstrates that the selection of forcing datasets and the metrics used to calibrate CLM5 significantly impact the model’s predictive accuracy in extreme event severity for both floods and droughts. Overall, the results from this study highlight the need to understand and account for forcing and parametric uncertainties in CLM5 simulations, particularly for hazard and risk assessments addressing hydrologic extremes.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1986

Measurement and application of fault latency

The time interval between the occurrence of a fault and the detection of the error caused by the fault is divided by the generation of that error into two parts: fault latency and error latency. Since the moment of error generation is not directly observable, all related works in the literature have dealt with only the sum of fault and error latencies, thereby making the analysis of their separate effects impossible. To remedy this deficiency, (1) a new methodology for indirectly measuring fault latency is presented; the distribution of fault latency is derived from the methodology; and (3) the knowledge of fault latency is applied to the analysis of two important examples. The proposed methodology has been implemented for measuring fault latency in the Fault-Tolerant Multiprocessor (FTMP) at the NASA Airlab. The experimental results show wide variations in the mean fault latencies of different function circuits within FTMP. Also, the measured distributions of fault latency are shown to have monotone hazard rates. Consequently, Gamma and Weibull distributions are selected for the least-squares fit as the distribution of fault latency.

Shin, K. G.↗
NASA NTRS2004

Special Purpose Crew Restraints for Teleoperation

With permanent human presence onboard the International Space Station (ISS), and long duration space missions being planned for the moon and Mars, humans will be living and working in microgravity over increasingly long periods of time. In addition to weightlessness, the confined nature of a spacecraft environment results in ergonomic challenges such as limited visibility, and access to the activity area. These challenges can result in prolonged periods of unnatural postures for the crew, ultimately causing pain, injury, and loss of productivity. Determining the right set of human factors requirements and providing an ergonomically designed environment is crucial to mission success. While a number of general purpose restraints have been used on ISS (handrails, foot loops), experience has shown that these general purpose restraints may not be optimal, or even acceptable for some tasks that have unique requirements. For example, some onboard activities require extreme stability (e.g., glovebox microsurgery), and others involve the use of arm, torso and foot movements in order to perform the task (e-g. robotic teleoperation); standard restraint systems will not work in these situations. The Usability Testing and Analysis Facility (WAF) at the NASA Johnson Space Center began evaluations of crew restraints for these special situations by looking at NASAs Robonaut. Developed by the Robot Systems Technology Branch, Robonaut is a humanoid robot that can be remotely operated through a tetepresence control system by an operator. It was designed to perform work in hazardous environments (e.g., Extra Vehicular Activities). A Robonaut restraint was designed, modeled for the population, and ultimately tested onboard the KC-135 microgravity aircraft. While in microgravity, participants were asked to get in and out of the restraint from different locations, perform maximum reach exercises, and finally to teleoperate Robonaut while in the restraint. The sessions were videotaped, and participants completed a questionnaire at the end of each flight day. Results from this evaluation are being used to develop the human factors design requirements for teleoperation tasks in microgravity.

Whitmore, Mihriban↗
NASA NTRS2017

One Step Plasma Passivation and Precision Cleaning

Over the past several years, Kennedy Space Center (KSC) researchers developed two solvent-free techniques for precision cleaning of ground support equipment (GSE) that possess low commodity requirements and produce small or no waste streams. During testing of low-pressure air plasma as one of these cleaning techniques, physical changes in the surface of stainless steel test pieces were observed; cursory testing revealed that the test part had developed a thick oxide layer on the surface compared to untreated parts. This result indicated that the plasma process might not only serve as a green technology for precision cleaning of parts, but it may also passivate the surface at the same time. Current methodology in use at KSC’s Components Refurbishment & Chemical Analysis (CRCA) Facility for passivation of corrosion-resistant steels for aerospace applications follows an SAE International Standard, AMS2700, where parts are submerged in either a nitric acid or nitric acid/sodium dichromate bath at predetermined temperatures and contact times. These baths require constant testing to ensure effective treatment, use corrosive and carcinogenic chemicals, and produce hazardous waste. The passivation bath is one of the multiple steps employed at the facility, while cleaning with multiple environmentally-unfriendly solvents comprise several more steps before parts are recertified to a specific cleanliness level in their clean room. Based on the behavior of the stainless steel surface during cleaning optimization studies, it was believed that the plasma technology could be extended to passivation, combining what is currently many steps into a single, solvent- and waste-free system.

Paul Hintze↗
DOE OSTI2021

Equatorial waves triggering extreme rainfall and floods in southwest Sulawesi, Indonesia

On the basis of detailed analysis of a case study and long-term climatology, it is shown that equatorial waves and their interactions serve as precursors for extreme rain and flood events in the central Maritime Continent region of southwest Sulawesi, Indonesia. Meteorological conditions on January 22, 2019, leading to heavy rainfall and devastating flooding in this area were studied. It is shown that a convectively coupled Kelvin wave (CCKW) and a convectively coupled Rossby wave (CCERW) embedded within the larger-scale envelope of the Madden-Julian Oscillation (MJO) enhanced convective phase, contributed to the onset of a mesoscale convective system which developed over the Java Sea. Low-Level convergence from the CCKW forced mesoscale convective organization and orographic ascent of moist air over the slopes of southwest Sulawesi. Climatological analysis shows that 92 % of December-January-February floods and 76% of extreme rain events in this region were immediately preceded by positive low-level westerly wind anomalies. It is estimated that both CCKWs and CCERWs propagating over Sulawesi double the chance of floods and extreme rain event development, which the probability of such hazardous events occurring during their combined activity is eight times greater than on a random day. While the MJO is a key component shaping tropical atmospheric variability, it is shown that its usefulness as a single factor for extreme weather-driven hazard prediction is limited.

Latos, Beata↗
DOE OSTI2022

Augmentation of WRF-Hydro to simulate overland-flow- and streamflow-generated debris flow susceptibility in burn scars

In steep wildfire-burned terrains, intense rainfall can produce large runoff that can trigger highly destructive debris flows. However, the ability to accurately characterize and forecast debris flow susceptibility in burned terrains using physics-based tools remains limited. Here, we augment the Weather Research and Forecasting Hydrological modeling system (WRF-Hydro) to simulate both overland and channelized flows and assess postfire debris flow susceptibility over a regional domain. We perform hindcast simulations using high-resolution weather-radar-derived precipitation and reanalysis data to drive non-burned baseline and burn scar sensitivity experiments. Our simulations focus on January 2021 when an atmospheric river triggered numerous debris flows within a wildfire burn scar in Big Sur – one of which destroyed California's famous Highway 1. Compared to the baseline, our burn scar simulation yields dramatic increases in total and peak discharge and shorter lags between rainfall onset and peak discharge, consistent with streamflow observations at nearby US Geological Survey (USGS) streamflow gage sites. For the 404 catchments located in the simulated burn scar area, median catchment-area-normalized peak discharge increases by ~ 450 % compared to the baseline. Catchments with anomalously high catchment-area-normalized peak discharge correspond well with post-event field-based and remotely sensed debris flow observations. We suggest that our regional postfire debris flow susceptibility analysis demonstrates WRF-Hydro as a compelling new physics-based tool whose utility could be further extended via coupling to sediment erosion and transport models and/or ensemble-based operational weather forecasts. Given the high-fidelity performance of our augmented version of WRF-Hydro, as well as its potential usage in probabilistic hazard forecasts, we argue for its continued development and application in postfire hydrologic and natural hazard assessments.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1977

Overview of NASA/Marshall Space Flight Center's program on knowledge of atmospheric processes

The Marshall Space Flight Center (MSFC) is charged with the responsibility to enhance aviation safety through improving understanding of various atmospheric phenomena. A brief discussion is presented concerning the tasks and work being accomplished by MSFC. The tasks are defined as follows: (1) to determine and define the turbulence and steady wind environments induced by buildings, towers, hills, trees, etc., (2) to identify, develop, and apply natural environment technology for the reconstruction and/or simulation of the natural environment for aircraft accident investigation and hazard identification, (3) to develop basic information about free atmosphere perturbations, (4) to develop and apply fog modification mathematical models to assess candidate fog modification schemes and to develop appropriate instrumentation to aquire basic data about fog. To accomplish these tasks MSFC has developed a program involving field data acquisition, wind tunnel studies, theoretical studies, data analysis, and flight simulation studies.

Camp, D. W.↗