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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 559 records · Page 31
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

A Review on Advanced Manufacturing for Hydrogen Storage Applications

Hydrogen is a notoriously difficult substance to store yet has endless energy applications. Thus, the study of long-term hydrogen storage, and high-pressure bulk hydrogen storage have been the subject of much research in the last several years. To create a research path forward, it is important to know what research has already been done, and what is already known about hydrogen storage. In this review, several approaches to hydrogen storage are addressed, including high-pressure storage, cryogenic liquid hydrogen storage, and metal hydride absorption. Challenges and advantages are offered based on reported research findings. Since the project looks closely at advanced manufacturing, techniques for the same are outlined as well. There are seven main categories into which most rapid prototyping styles fall. Each is briefly explained and illustrated as well as some generally accepted advantages and drawbacks to each style. An overview of hydrogen adsorption on metal hydrides, carbon fibers, and carbon nanotubes are presented. The hydrogen storage capacities of these materials are discussed as well as the differing conditions in which the adsorption was performed under. Concepts regarding storage shape and materials accompanied by smaller-scale advanced manufacturing options for hydrogen storage are also presented.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Measuring Thickness-Dependent Relative Light Yield and Detection Efficiency of Scintillator Screens

Digital camera-based neutron imaging systems consisting of a neutron scintillator screen optically coupled to a digital camera are the most common digital neutron imaging system used in the neutron imaging community and are available at any state-of-the-art imaging facility world-wide. Neutron scintillator screens are the integral component of these imaging system that directly interacts with the neutron beam and dictates the neutron capture efficiency and image quality limitations of the imaging system. This work describes a novel approach for testing neutron scintillators that provides a simple and efficient way to measure relative light yield and detection efficiency over a range of scintillator thicknesses using a single scintillator screen and only a few radiographs. Additionally, two methods for correlating the screen thickness to the measured data were implemented and compared. An example 6LiF:ZnS scintillator screen with nominal thicknesses ranging from 0–300 μm was used to demonstrate this approach. The multi-thickness screen and image and data processing methods are not exclusive to neutron scintillator screens but could be applied to X-ray imaging as well. This approach has the potential to benefit the entire radiographic imaging community by offering an efficient path forward for manufacturers to develop higher-performance scintillators and for imaging facilities and service providers to determine the optimal screen parameters for their particular beam and imaging system.

42 ENGINEERING↗
DOE OSTI2017

Radar Detectability Studies of Slow and Small Zodiacal Dust Cloud Particles. III. The Role of Sodium and the Head Echo Size on the Probability of Detection

We present a path forward on a long-standing issue concerning the flux of small and slow meteoroids, which are believed to be the dominant portion of the incoming meteoric mass flux into the Earth’s atmosphere. Such a flux, which is predicted by dynamical dust models of the Zodiacal Cloud, is not evident in ground-based radar observations. For decades this was attributed to the fact that the radars used for meteor observations lack the sensitivity to detect this population, due to the small amount of ionization produced by slow-velocity meteors. Such a hypothesis has been challenged by the introduction of meteor head echo (HE) observations with High Power and Large Aperture radars, in particular the Arecibo 430 MHz radar. Janches et al. developed a probabilistic approach to estimate the detectability of meteors by these radars and initially showed that, with the current knowledge of ablation and ionization, such particles should dominate the detected rates by one to two orders of magnitude compared to the actual observations. In this paper, we include results in our model from recently published laboratory measurements, which showed that (1) the ablation of Na is less intense covering a wider altitude range; and (2) the ionization probability, β{sub ip}, for Na atoms in the air is up to two orders of magnitude smaller for low speeds than originally believed. By applying these results and using a somewhat smaller size of the HE radar target we offer a solution that reconciles these observations with model predictions.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2025

Enabling Robust Exoplanet Atmospheric Retrievals with Gaussian Processes

Atmospheric retrievals are essential tools for interpreting exoplanet transmission and eclipse spectra, enabling quantitative constraints on the chemical composition, aerosol properties, and thermal structure of planetary atmospheres. The James Webb Space Telescope (JWST) offers unprecedented spectral precision, resolution, and wavelength coverage, unlocking transformative insights into the formation, evolution, climate, and potential habitability of planetary systems. However, this opportunity is accompanied by challenges: modeling assumptions and unaccounted-for noise or signal sources can bias retrieval outcomes and their interpretation. To address these limitations, we introduce a Gaussian process (GP)-aided atmospheric retrieval framework that flexibly accounts for unmodeled features and correlated noise in exoplanet spectra. We validate this method on synthetic JWST observations, and show that GP-aided retrievals reduce bias in inferred abundances and better capture model–data mismatches than traditional approaches. We also introduce the concept of mean squared error to quantify the trade-off between bias and variance, arguing that this metric more accurately reflects retrieval performance than bias alone. We then reanalyze the NIRISS/SOSS JWST transmission spectrum of WASP-96 b, finding that GP-aided retrievals yield broader constraints on CO 2 and H 2 O, possibly alleviating tension between previous retrieval results and equilibrium predictions. Our GP framework provides precise and accurate constraints while highlighting regions where models fail to explain the data. As JWST matures and future facilities come online, a deeper understanding of the limitations of both data and models will be essential, and GP-enabled retrievals like the one presented here offer a principled path forward.

Rotman, Yoav [Arizona State Univ., Tempe, AZ (Unit↗
DOE OSTI2015

Policy and Technical Issues Facing a Fissile Material (Cutoff) Treaty. Chapter 14

We report the largest obstacle to creating nuclear weapons, starting with the ones that destroyed Hiroshima and Nagasaki, has been to make sufficient quantities of fissile materials – highly enriched uranium (HEU) and plutonium – to sustain an explosive fission chain reaction.1 Recognition of this fact has, for more than fifty years, underpinned both the support for and the opposition to adoption of an international treaty banning at a minimum the production of more fissile materials for nuclear weapons, commonly referred to as a fissile material cutoff treaty (FMCT).

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗
DOE OSTI2015

Pan-spectral observing system simulation experiments of shortwave reflectance and long-wave radiance for climate model evaluation

Abstract. Top-of-atmosphere (TOA) spectrally resolved shortwave reflectances and long-wave radiances describe the response of the Earth's surface and atmosphere to feedback processes and human-induced forcings. In order to evaluate proposed long-duration spectral measurements, we have projected 21st Century changes from the Community Climate System Model (CCSM3.0) conducted for the Intergovernmental Panel on Climate Change (IPCC) A2 Emissions Scenario onto shortwave reflectance spectra from 300 to 2500 nm and long-wave radiance spectra from 2000 to 200 cm –1 at 8 nm and 1 cm –1 resolution, respectively. The radiative transfer calculations have been rigorously validated against published standards and produce complementary signals describing the climate system forcings and feedbacks. Additional demonstration experiments were performed with the Model for Interdisciplinary Research on Climate (MIROC5) and Hadley Centre Global Environment Model version 2 Earth System (HadGEM2-ES) models for the Representative Concentration Pathway 8.5 (RCP8.5) scenario. The calculations contain readily distinguishable signatures of low clouds, snow/ice, aerosols, temperature gradients, and water vapour distributions. The goal of this effort is to understand both how climate change alters reflected solar and emitted infrared spectra of the Earth and determine whether spectral measurements enhance our detection and attribution of climate change. This effort also presents a path forward to understand the characteristics of hyperspectral observational records needed to confront models and inline instrument simulation. Such simulation will enable a diverse set of comparisons between model results from coupled model intercomparisons and existing and proposed satellite instrument measurement systems.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2026

Commercialization of Reflected Target Non-Intrusive Assessment (ReTNA) Tool, for Indoor Optical Analysis of Heliostats

Under HelioCon, NLR began developing a new optical measurement system, called Reflected Target Non-Intrusive Assessment (ReTNA). ReTNA has shown promise towards addressing metrology gaps for heliostat used in concentrated solar thermal (CST) plant. This project is focused on advancing this measurement system from the laboratory into industry, where it can provide valuable information for heliostat developers during research, development, and qualification of a heliostat design, and be used for quality assurance during heliostat manufacture. Over the course of this project, ReTNA was deployed at several commercial heliostat facilities. The system developed and deployed with the primary project partner, Solar Dynamics LLC, is described in detail. The report discusses each project Milestone, the ending status, the achieved value, and how these Milestones improve and qualify the ReTNA measurement tool. Finally, the final report covers the market advancements, path forward, commercial successes, and lessons learned. Final Technical report for TCF Base Technology-Specific project TCF-23-20118, Commercialization of Reflected Target Non-Intrusive Assessment (ReTNA) tool, for indoor optical analysis of Heliostats.

14 SOLAR ENERGY↗
DOE OSTI2026

Guideline for Characterizing and Evaluating a Candidate Project Site for Solar Thermal Applications

This document presents a structured procedure for characterizing and evaluating candidate project sites for concentrating solar power (CSP) and solar heat for industrial processes (SHIP) applications. The objective is to provide project developers, researchers, and other stakeholders with a consistent, technology-agnostic framework for early-stage site assessment, enabling informed decision-making prior to significant investment in project development. Site selection is a critical factor in project success or failure for both CSP and SHIP projects. Key factors such as solar resource availability, land characteristics, environmental and regulatory constraints, infrastructure availability, and community context are determined by the choice of project site and can materially impact project performance, cost, schedule, and overall viability. This procedure is designed to systematically evaluate these factors, identify potential fatal flaws, and prioritize the most favorable candidate sites for further development. The process begins with rapid screening-level evaluation, using publicly available data to assess solar resource, land availability and suitability, zoning and land-use compatibility, and exclusion zones such as protected lands or sensitive habitats. Sites that meet the minimum screening criteria advance to a more detailed characterization. Subsequent sections of this report provide guidance for a next-level assessment of the most important technical and environmental parameters, including: 1) Solar resource quality, variability, and uncertainty using multiyear datasets and, where appropriate, on-site measurement campaigns; 2) Meteorological conditions such as wind, temperature, extreme weather events, and soiling impacts; 3) Land characteristics including slope, shading, and geotechnical conditions; and 4) Environmental and regulatory considerations, including permitting processes, endangered species, cultural resources, and visual impacts. The procedure also addresses infrastructure and integration considerations, including: 1) Grid interconnection requirements for CSP power generation projects; 2) Electrical and operational integration for SHIP facilities; 3) Water availability, quality, and permitting constraints, which are particularly critical for CSP in arid regions; and 4) Site access, construction logistics, and availability of workforce and supporting services. Recognizing the importance of social and economic context, the procedure includes evaluation of community engagement factors, such as stakeholder sentiment, proximity to sensitive visual receptors, workforce development opportunities, and local economic incentives. The outputs of these assessments are synthesized in a cost and risk evaluation, translating site characteristics into expected impacts on capital cost, operating cost, schedule, and technical risk. This is complemented by screening-level performance modeling, including 8760 simulations and long-term projections, to quantify expected energy or thermal output, assess variability thereof, and support comparison between candidate sites. Finally, the procedure provides high-level guidance on a structured go/no-go decision framework, categorizing sites based on identified risks and constraints, and outlining a clear path forward to feasibility studies and front-end engineering design for viable projects. By standardizing the site characterization process across both CSP and SHIP applications, this guideline aims to: 1) Improve consistency and transparency in early-stage project evaluation; 2) Reduce development risk and avoid investment in nonviable project sites; 3) Support collaboration between developers, researchers, and public agencies; and 4) Accelerate successful deployment of concentrating solar technologies for both power generation and industrial process heat.

14 SOLAR ENERGY↗
DOE OSTI2018

Stellarator Research Opportunities: A Report of the National Stellarator Coordinating Committee

This document is the product of a stellarator community workshop, organized by the National Stellarator Coordinating Committee and referred to as Stellcon, that was held in Cambridge, Massachusetts in February 2016, hosted by MIT. The workshop was widely advertised, and was attended by 40 scientists from 12 different institutions including national labs, universities and private industry, as well as a representative from the Department of Energy. The final section of this document describes areas of community wide consensus that were developed as a result of the discussions held at that workshop. Areas where further study would be helpful to generate a consensus path forward for the US stellarator program are also discussed. The program outlined in this document is directly responsive to many of the strategic priorities of FES as articulated in ‘‘Fusion Energy Sciences: A Ten-Year Perspective (2015–2025)’’ [1]. The natural disruption immunity of the stellarator directly addresses ‘‘Elimination of transient events that can be deleterious to toroidal fusion plasma confinement devices’’ an area of critical importance for the US fusion energy sciences enterprise over the next decade. Another critical area of research ‘‘Strengthening our partnerships with international research facilities,’’ is being significantly advanced on the W7-X stellarator in Germany and serves as a test-bed for development of successful international collaboration on ITER. This report also outlines how materials science as it relates to plasma and fusion sciences, another critical research area, can be carried out effectively in a stellarator. Additionally, significant advances along two of the Research Directions outlined in the report; ‘‘Burning Plasma Science: Foundations—Next-generation research capabilities’’, and ‘‘Burning Plasma Science: Long pulse—Sustainment of Long-Pulse Plasma Equilibria’’ are proposed.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
NASA NTRS1979

Total aircraft flight-control system - Balanced open- and closed-loop control with dynamic trim maps

The availability of the airborne digital computer has made possible a Total Aircraft Flight Control System (TAFCOS) that uses virtually the complete nonlinear propulsive and aerodynamic data for the aircraft to construct dynamic trim maps that represent an inversion of the aircraft model. The trim maps, in series with the aircraft, provide essentially a linear feed-forward path. Basically, open-loop trajectory control is employed with only a small perturbation feedback signal required to compensate for inaccuracy in the aircraft model and for external disturbances. Simulation results for application to an automatic carrier-landing system are presented. Flight-test results for a STOL aircraft operating automatically over a major portion of its flight regime are presented. The concept promises a more rapid and straightforward design from aerodynamic principles, particularly for highly nonlinear configurations, and requires substantially less digital computer capacity than conventional automatic flight-control system designs.

Smith, G. A.↗
NASA NTRS1991

Application of modern control design methodology to oblique wing research aircraft

A Linear Quadratic Regulator synthesis technique was used to design an explicit model following control system for the Oblique Wing Research Aircraft (OWRA). The forward path model (Maneuver Command Generator) was designed to incorporate the desired flying qualities and response decoupling. The LQR synthesis was based on the use of generalized controls, and it was structured to provide a proportional/integral error regulator with feedforward compensation. An unexpected consequence of this design approach was the ability to decouple the control synthesis into separate longitudinal and lateral directional designs. Longitudinal and lateral directional control laws were generated for each of the nine design flight conditions, and gain scheduling requirements were addressed. A fully coupled 6 degree of freedom open loop model of the OWRA along with the longitudinal and lateral directional control laws was used to assess the closed loop performance of the design. Evaluations were performed for each of the nine design flight conditions.

Vincent, James H.↗
NASA NTRS1995

Neural-Network Controller For Vibration Suppression

Neural-network-based adaptive-control system proposed for vibration suppression of flexible space structures. Controller features three-layer neural network and utilizes output feedback. Measurements generated by various sensors on structure. Feed forward path also included to speed up response in case plant exhibits predominantly linear dynamic behavior. System applicable to single-input single-output systems. Work extended to multiple-input multiple-output systems as well.

Boussalis, Dhemetrios↗
NASA NTRS2006

Integrated System Health Management (ISHM) Technology Demonstration Project Final Report

Integrated System Health Management (ISHM) is an essential capability that will be required to enable upcoming explorations mission systems such as the Crew Exploration Vehicle (CEV) and Crew Launch Vehicle (CLV), as well as NASA aeronautics missions. However, the lack of flight experience and available test platforms have held back the infusion by NASA Ames Research Center (ARC) and the Jet Propulsion Laboratory (JPL) of ISHM technologies into future space and aeronautical missions. To address this problem, a pioneer project was conceived to use a high-performance aircraft as a low-cost proxy to develop, mature, and verify the effectiveness of candidate ISHM technologies. Given the similarities between spacecraft and aircraft, an F/A-18 currently stationed at Dryden Flight Research Center (DFRC) was chosen as a suitable host platform for the test bed. This report describes how the test bed was conceived, how the technologies were integrated on to the aircraft, and how these technologies were matured during the project. It also describes the lessons learned during the project and a forward path for continued work.

Mackey, Ryan↗
NASA NTRS2008

Advanced Imaging for Space Science

Future NASA interferometric missions will realize high-resolution with less mass and volume compared to filled-apertures thus saving in cost over comparable filled-aperture systems. However, interferometeric aperture systems give reduced sensitivity requiring longer integration times to achieve a desired signal-to-noise ratio but is likely the only cost effective path forward for high-resolution space imaging.

Lyon, Richard G.↗
NASA NTRS2009

802.16e System Profile for NASA Extra-Vehicular Activities

This report identifies an 802.16e system profile that is applicable to a lunar surface wireless network, and specifically for meeting extra-vehicular activity (EVA) data flow requirements. EVA suit communication needs are addressed. Design-driving operational scenarios are considered. These scenarios are then used to identify a configuration of the 802.16e system (system profile) that meets EVA requirements, but also aim to make the radio realizable within EVA constraints. Limitations of this system configuration are highlighted. An overview and development status is presented by Toyon Research Corporation concerning the development of an 802.16e compatible modem under NASA s Small Business Innovative Research (SBIR) Program. This modem is based on the recommended system profile developed as part of this report. Last, a path forward is outlined that presents an evolvable solution for the EVA radio system and lunar surface radio networks. This solution is based on a custom link layer, and 802.16e compliant physical layer compliant to the identified system profile, and a later progression to a fully interoperable 802.16e system.

Foore, Lawrence R.↗
NASA NTRS2009

Balloon Exoplanet Nulling Interferometer (BENI)

We evaluate the feasibility of using a balloon-borne nulling interferometer to detect and characterize exosolar planets and debris disks. The existing instrument consists of a 3-telescope Fizeau imaging interferometer with 3 fast steering mirrors and 3 delay lines operating at 800 Hz for closed-loop control of wavefront errors and fine pointing. A compact visible nulling interferometer is under development which when coupled to the imaging interferometer would in-principle allow deep suppression of starlight. We have conducted atmospheric simulations of the environment above 100,000 feet and believe balloons are a feasible path forward towards detection and characterization of a limited set of exoplanets and their debris disks. Herein we will discuss the BENI instrument, the balloon environment and the feasibility of such as mission.

Lyon, Richard G.↗
NASA NTRS2010

NASA Supportability Engineering Implementation Utilizing DoD Practices and Processes

The Ares I design and development program made the determination early in the System Design Review Phase to utilize DoD ILS and LSA approach for supportability engineering as an integral part of the system engineering process. This paper is to provide a review of the overall approach to design Ares-I with an emphasis on a more affordable, supportable, and sustainable launch vehicle. Discussions will include the requirements development, design influence, support concept alternatives, ILS and LSA planning, Logistics support analyses/trades performed, LSA tailoring for NASA Ares Program, support system infrastructure identification, ILS Design Review documentation, Working Group coordination, and overall ILS implementation. At the outset, the Ares I Project initiated the development of the Integrated Logistics Support Plan (ILSP) and a Logistics Support Analysis process to provide a path forward for the management of the Ares-I ILS program and supportability analysis activities. The ILSP provide the initial planning and coordination between the Ares-I Project Elements and Ground Operation Project. The LSA process provided a system engineering approach in the development of the Ares-I supportability requirements; influence the design for supportability and development of alternative support concepts that satisfies the program operability requirements. The LSA planning and analysis results are documented in the Logistics Support Analysis Report. This document was required during the Ares-I System Design Review (SDR) and Preliminary Design Review (PDR) review cycles. To help coordinate the LSA process across the Ares-I project and between programs, the LSA Report is updated and released quarterly. A System Requirement Analysis was performed to determine the supportability requirements and technical performance measurements (TPMs). Two working groups were established to provide support in the management and implement the Ares-I ILS program, the Integrated Logistics Support Working Group (ILSWG) and the Logistics Support Analysis Record Working Group (LSARWG). The Ares I ILSWG is established to assess the requirements and conduct, evaluate analyses and trade studies associated with acquisition logistic and supportability processes and to resolve Ares I integrated logistics and supportability issues. It established a strategic collaborative alliance for coordination of Logistics Support Analysis activates in support of the integrated Ares I vehicle design and development of logistics support infrastructure. A Joint Ares I - Orion LSAR Working Group was established to: 1) Guide the development of Ares-I and Orion LSAR data and serve as a model for future Constellation programs, 2) Develop rules and assumptions that will apply across the Constellation program with regards to the program's LSAR development, and 3) Maintain the Constellation LSAR Style Guide.

Smith, David A.↗
NASA NTRS2010

Assessment of Hybrid RANS/LES Turbulence Models for Aeroacoustics Applications

Predicting the noise from aircraft with exposed landing gear remains a challenging problem for the aeroacoustics community. Although computational fluid dynamics (CFD) has shown promise as a technique that could produce high-fidelity flow solutions, generating grids that can resolve the pertinent physics around complex configurations can be very challenging. Structured grids are often impractical for such configurations. Unstructured grids offer a path forward for simulating complex configurations. However, few unstructured grid codes have been thoroughly tested for unsteady flow problems in the manner needed for aeroacoustic prediction. A widely used unstructured grid code, FUN3D, is examined for resolving the near field in unsteady flow problems. Although the ultimate goal is to compute the flow around complex geometries such as the landing gear, simpler problems that include some of the relevant physics, and are easily amenable to the structured grid approaches are used for testing the unstructured grid approach. The test cases chosen for this study correspond to the experimental work on single and tandem cylinders conducted in the Basic Aerodynamic Research Tunnel (BART) and the Quiet Flow Facility (QFF) at NASA Langley Research Center. These configurations offer an excellent opportunity to assess the performance of hybrid RANS/LES turbulence models that transition from RANS in unresolved regions near solid bodies to LES in the outer flow field. Several of these models have been implemented and tested in both structured and unstructured grid codes to evaluate their dependence on the solver and mesh type. Comparison of FUN3D solutions with experimental data and numerical solutions from a structured grid flow solver are found to be encouraging.

Vatsa, Veer N.↗