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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS1999

C/SiC Component & Material Analysis, Attachment Verification, & Blisk Turbopump Testing

Ceramic composite blisk components constructed of carbon fibers & silicon carbide ceramic matrix have been fabricated and tested. Room and cryogenic torque testing have verified the attachment configuration. The polar and quasi-isotropic blisks have been proof spun, balanced, and tested in the Simplex turbopump. Foreign particle impact analysis was conducted for C/SiC. Data and manufacturing lessons learned are significantly benefiting the development of the Reusable Launch Vehicle's ceramic matrix composite integrally bladed disk.

Effinger, Michael R.↗
NASA NTRS1995

Structural Damage Prediction and Analysis for Hypervelocity Impact: Consulting

A portion of the contract NAS8-38856, 'Structural Damage Prediction and Analysis for Hypervelocity Impacts,' from NASA Marshall Space Flight Center (MSFC), included consulting which was to be documented in the final report. This attachment to the final report contains memos produced as part of that consulting.

Source record↗
NASA NTRS2015

Risk-Based Causal Modeling of Airborne Loss of Separation

Maintaining safe separation between aircraft remains one of the key aviation challenges as the Next Generation Air Transportation System (NextGen) emerges. The goals of the NextGen are to increase capacity and reduce flight delays to meet the aviation demand growth through the 2025 time frame while maintaining safety and efficiency. The envisioned NextGen is expected to enable high air traffic density, diverse fleet operations in the airspace, and a decrease in separation distance. All of these factors contribute to the potential for Loss of Separation (LOS) between aircraft. LOS is a precursor to a potential mid-air collision (MAC). The NASA Airspace Operations and Safety Program (AOSP) is committed to developing aircraft separation assurance concepts and technologies to mitigate LOS instances, therefore, preventing MAC. This paper focuses on the analysis of causal and contributing factors of LOS accidents and incidents leading to MAC occurrences. Mid-air collisions among large commercial aircraft are rare in the past decade, therefore, the LOS instances in this study are for general aviation using visual flight rules in the years 2000-2010. The study includes the investigation of causal paths leading to LOS, and the development of the Airborne Loss of Separation Analysis Model (ALOSAM) using Bayesian Belief Networks (BBN) to capture the multi-dependent relations of causal factors. The ALOSAM is currently a qualitative model, although further development could lead to a quantitative model. ALOSAM could then be used to perform impact analysis of concepts and technologies in the AOSP portfolio on the reduction of LOS risk.

Geuther, Steven C.↗
NASA NTRS2015

Research-Based Monitoring, Prediction, and Analysis Tools of the Spacecraft Charging Environment for Spacecraft Users

The Space Weather Research Center (http://swrc. gsfc.nasa.gov) at NASA Goddard, part of the Community Coordinated Modeling Center (http://ccmc.gsfc.nasa.gov), is committed to providing research-based forecasts and notifications to address NASA's space weather needs, in addition to its critical role in space weather education. It provides a host of services including spacecraft anomaly resolution, historical impact analysis, real-time monitoring and forecasting, tailored space weather alerts and products, and weekly summaries and reports. In this paper, we focus on how (near) real-time data (both in space and on ground), in combination with modeling capabilities and an innovative dissemination system called the integrated Space Weather Analysis system (http://iswa.gsfc.nasa.gov), enable monitoring, analyzing, and predicting the spacecraft charging environment for spacecraft users. Relevant tools and resources are discussed.

space weather↗
NASA NTRS1993

Test report for single event effects of the 80386DX microprocessor

The Jet Propulsion Laboratory Section 514 Single Event Effects (SEE) Testing and Analysis Group has performed a series of SEE tests of certain strategic registers of Intel's 80386DX CHMOS 4 microprocessor. Following a summary of the test techniques and hardware used to gather the data, we present the SEE heavy ion and proton test results. We also describe the registers tested, along with a system impact analysis should these registers experience a single event upset.

Watson, R. Kevin↗
NASA NTRSDate not supplied

NASA Space Nuclear Propulsion (SNP) MBSE Initiatives

NASA’s Space Nuclear Propulsion (SNP) program is developing several MagicDraw SysML models to support the development of high performance Nuclear Thermal Rocket Engines (NTRE). Currently, the Demonstration Rocket for Agile Cislunar Operations (DRACO) project is aiming to perform the first ever flight demonstration of an NTRE, and NASA is developing a DRACO Insight Project Model Based Systems Engineering (MBSE) model to capture, define, analyze, and report on the flight and ground test system architecture, functional behavior, requirements, risks, and lessons learned. Additional models are in work for engine component trade trees, fault detection sensor coverage analysis using a Goal Function Tree (GFT) plugin, stakeholder engagement, and technology maturation projects. The GFT plugin is the Galois, Inc. Failure Recovery Instruction Generation using Automata derived from Traditional Engineering models (FRIGATE) tool. A new capability for Jira to MagicDraw data sharing using the OpenPDM collaboration platform is under development with partner Victory Solutions, Inc. to enhance risk impact analysis.

Space Nuclear Propulsion (SNP)↗
NASA NTRS1988

Surface crack analysis applied to impact damage in a thick graphite-epoxy composite

The residual tensile strength of a thick graphite/epoxy composite with impact damage was predicted using surface crack analysis. The damage was localized to a region directly beneath the impact site and extended only part way through the laminate. The damaged region contained broken fibers, and the locus of breaks in each layer resembled a crack perpendicular to the direction of the fibers. In some cases, the impacts broke fibers without making a visible crater. The impact damage was represented as a semi-elliptical surface crack with length and depth equal to that of the impact damage. The maximum length and depth of the damage were predicted with a stress analysis and a maximum shear stress criterion. The predictions and measurements of strength were in good agreement.

Poe, C. C., Jr.↗
NASA NTRS1990

Surface crack analysis applied to impact damage in a thick graphite/epoxy composite

The residual tensile strength of a thick graphite/epoxy composite with impact damage was predicted using surface crack analysis. The damage was localized to a region directly beneath the impact site and extended only part way through the laminate. The damaged region contained broken fibers, and the locus of breaks in each layer resembled a crack perpendicular to the direction of the fibers. In some cases, the impacts broke fibers without making a visible crater. The impact damage was represented as a semi-elliptical surface crack with length and depth equal to that of the impact damage. The maximum length and depth of the damage were predicted with a stress analysis and a maximum shear stress criterion. The predictions and measurements of strength were in good agreement.

Poe, Clarence C., Jr.↗
NASA NTRS1978

Energy impact assessment of NASA's past, present, and future space launch vehicles

An approach to analyze the total energy required for overall support of space launch vehicles is outlined along with some of the basic data required for such analyses. Selected results obtained by using this approach are presented for various past (some are already phased out), present, and future NASA launch vehicles, including an estimate of the total annual energy required to support one projected NASA launch vehicle traffic model. The material presented is expected to give a better insight into the details of an energy impact analysis. Major conclusions are that: (1) for expendable launch vehicle systems, the energy required to manufacture hardware and support launch operations is most significant; (2) for totally reusable systems, the energy required to process/manufacture propellants and fluids is by far the most significant contributor; and (3) up to 1991, the projected highest annual energy requirement for the NASA launch vehicles does not constitute a significant energy impact relative to the nation's total energy needs.

Rice, E. E.↗
NASA NTRS1995

Line Profile of H Lyman (alpha) from Dissociative Excitation of H2 with Application to Jupiter

Observations of the H Lyman(alpha) (Ly-alpha) emission from Jupiter have shown pronounced emissions, exceeding solar fluorescence, in the polar aurora and equatorial "bulge" regions. The H Ly-alpha line profiles from these regions are broader than expected, indicating high-energy processes producing fast atoms as determined from the observed Doppler broadening. Toward understanding that process a high-resolution ultraviolet (UV) spectrometer was employed for the first measurement of the H Ly-alpha emission Doppler profile from dissociative excitation of H2 by electron impact. Analysis of the deconvolved line profile reveals the existence of a narrow central peak of 40 +/- 4 mA full width at half maximum and a broad pedestal base about 240 mA wide. Two distinct dissociation mechanisms account for this Doppler structure. Slow H(2p) atoms characterized by a distribution function with peak energy near 80 meV produce the peak profile, which is nearly independent of the electron impact energy. Slow H(2p) atoms arise from direct dissociation and predissociation of singly excited states which have a dissociation limit of 14.68 eV. The wings of H Ly-alpha arise from dissociative excitation of a series of doubly excited states which cross the Franck-Condon region between 23 and 40 eV. The profile of the wings is dependent on the electron impact energy, and the distribution function of fast H(2p) atoms is therefore dependent on the electron impact energy. The fast atom kinetic energy distribution at 100 eV electron impact energy spans the energy range from 1 to 10 eV with a peak near 4 eV. For impact energies above 23 eV the fast atoms contribute to a slightly asymmetric structure of the line profile. The absolute cross sections of the H Ly-alpha line peak and wings were measured over the range from 0 to 200 eV. Analytic model coefficients are given for the measured cross sections which can be applied to planetary atmosphere auroral and dayglow calculations. The dissociative excitation process, while one contributing process, appears insufficient by itself to explain the line broadening observed at Jupiter.

Ajello, Joseph M.↗
NASA NTRS2011

Browsing Space Weather Data and Models with the Integrated Space Weather Analysis (iSWA) System

The Integrated Space Weather Analysis (iSWA) System is a comprehensive web-based platform for space weather information that combines data from solar, heliospheric and geospace observatories with forecasts based on the most advanced space weather models. The iSWA system collects, generates, and presents a wide array of space weather resources in an intuitive, user-configurable, and adaptable format - thus enabling users to respond to current and future space weather impacts as well as enabling post-impact analysis. iSWA currently provides over 200 data and modeling products, and features a variety of tools that allow the user to browse, combine, and examine data and models from various sources. This presentation will consist of a summary of the iSWA products and an overview of the customizable user interfaces, and will feature several tutorial demonstrations highlighting the interactive tools and advanced capabilities.

Maddox, Marlo M.↗
NASA NTRS2018

Socioeconomic Impact Evaluation for Near Real-time Flood Detection in the Lower Mekong River Basin

Flood events pose a severe threat to communities in the Lower Mekong River Basin. The combination of population growth, urbanization, and economic development exacerbate the impacts of these events. Flood damage assessments, critical for understanding the effects of flooding on the local population and informing decision-makers about future risks, are frequently used to quantify the economic losses due to storms. Remote sensing systems provide a valuable tool for monitoring flood conditions and assessing their severity more rapidly than traditional post-event evaluations. The frequency and severity of extreme flood events are projected to increase, further highlighting the need for improved flood monitoring and impact analysis. In this study we integrate a socioeconomic damage assessment model with a near real-time flood remote sensing and decision support tool (NASA's Project Mekong). Direct damages to populations, infrastructure, and land cover are assessed using the 2011 Southeast Asian flood as a case study. Improved land use/land cover and flood depth assessments result in rapid loss estimates throughout the Mekong River Basin. Results suggest that rapid initial estimates of flood impacts can provide valuable information to governments, international agencies, and disaster responders in the wake of extreme flood events.

Mekong Basin↗
NASA NTRS1992

A systems analysis of the impact of navigation instrumentation on-board a Mars rover, based on a covariance analysis of navigation performance

As part of the Space Exploration Initiative, the exploration of Mars will undoubtedly require the use of rovers, both manned and unmanned. Many mission scenarios have been developed, incorporating rovers which range in size from a few centimeters to ones large enough to carry a manned crew. Whatever the mission, accurate navigation of the rover on the Martian surface will be necessary. This thesis considers the initial rover missions, where minimal in-situ navigation aids will be available on Mars. A covariance analysis of the rover's navigation performance is conducted, assuming minimal on-board instrumentation (gyro compass and speedometer), a single orbiting satellite, and a surface beacon at the landing site. Models of the on-board instruments are varied to correspond to the accuracy of various levels of these instruments currently available. A comparison is made with performance of an on-board IMU. Landing location and satellite orbits are also varied.

Leber, Douglas Eric↗
NASA NTRS1984

Large-Scale Advanced Prop-Fan (LAP) blade design

This report covers the design analysis of a very thin, highly swept, propeller blade to be used in the Large-Scale Advanced Prop-Fan (LAP) test program. The report includes: design requirements and goals, a description of the blade configuration which meets requirements, a description of the analytical methods utilized/developed to demonstrate compliance with the requirements, and the results of these analyses. The methods described include: finite element modeling, predicted aerodynamic loads and their application to the blade, steady state and vibratory response analyses, blade resonant frequencies and mode shapes, bird impact analysis, and predictions of stalled and unstalled flutter phenomena. Summarized results include deflections, retention loads, stress/strength comparisons, foreign object damage resistance, resonant frequencies and critical speed margins, resonant vibratory mode shapes, calculated boundaries of stalled and unstalled flutter, and aerodynamic and acoustic performance calculations.

Violette, John A.↗
NASA NTRS1996

Line Profile of H Lyman-Beta Emission from Dissociative Excitation of H2

A high-resolution ultraviolet spectrometer was employed for a measurement of the H Lyman-Beta(H L(sub Beta)) emission Doppler line profile at 1025.7 A from dissociative excitation of H2 by electron impact. Analysis of the deconvolved line profile reveals the existence of a narrow central peak, less than 30 mA full width at half maximum (FWHM), and a broad pedestal base about 260 mA FWHM. Analysis of the red wing of the line profile is complicated by a group of Wemer and Lyman rotational lines 160-220 mA from the line center. Analysis of the blue wing of the line profile gives the kinetic-energy distribution. There are two main kinetic-energy components to the H(3p) distribution: (1) a slow distribution with a peak value near 0 eV from singly excited states, and (2) a fast distribution with a peak contribution near 7 eV from doubly excited states. Using two different techniques, the absolute cross section of H L(sub Beta)p is found to be 3.2+/-.8 x 10(exp -19)sq cm at 100-eV electron impact energy. The experimental cross-section and line-profile results can be compared to previous studies of H(alpha) (6563.7 A) for principal quantum number n=3 and L(sub alpha)(1215.7 A) for n=2.

Ajello, Joseph M.↗
NASA NTRS2017

Lightweight Multifunctional Planetary Probe for Extreme Environment Exploration and Locomotion

The demand to explore new worlds requires the development of advanced technologies that enable landed science on uncertain terrains or in hard to reach locations. As a result, contemporary Entry, Descent, Landing, (EDL) and additional locomotion (EDLL) profiles are becoming increasingly more complex, with the introduction of lifting/guided entries, hazard avoidance on descent, and a plethora of landing techniques including airbags and the skycrane maneuver. The inclusion of each of these subsystems into a mission profile is associated with a substantial mass penalty. This report explores the new all-in-one entry vehicle concept, TANDEM, a new combined EDLL concept, and compares it to the current state of the art EDL systems. The explored system is lightweight and collapsible and provides the capacity for lifting/guided entry, guided descent, hazard avoidance, omnidirectional impact protection and surface locomotion without the aid of any additional subsystems. This Phase I study explored: 1. The capabilities and feasibility of the TANDEM concept as an EDLL vehicle. 2. Extensive impact analysis to ensure mission success in unfavorable landing conditions, and safe landing in Tessera regions. 3. Development of a detailed design for a conceptual mission to Venus. As a result of our work it was shown that: 1. TANDEM provides additional benefits over the Adaptive, Deployable Entry Placement Technology (ADEPT) including guided descent and surface locomotion, while reducing the mass by 38% compared to the ADEPT-VITaL mission. 2. Demonstrated that the design of tensegrity structures, and TANDEM specifically, grows linearly with an increase in velocity, which was previously unknown. 3. Investigation of surface impact revealed a promising results that suggest a properly configured TANDEM vehicle can safely land and preform science in the Tessera regions, which was previously labeled by the Decadal Survey as, largely inaccessible despite its high scientific interest. This work has already resulted in a NASA TM and will be submitted to the Journal of Spacecraft and Rockets.

landing techniques↗
NASA NTRS2020

The GGCMI Phase 2 emulators: global gridded crop model responses to changes in CO2, temperature, water, and nitrogen (version 1.0)

Statistical emulation allows combining advantageous features of statistical and process-based crop models for understanding the effects of future climate changes on crop yields. We describe here the development of emulators for nine process-based crop models and five crops using output from the Global Gridded Model Intercomparison Project (GGCMI) Phase 2. The GGCMI Phase 2 experiment is designed with the explicit goal of producing a structured training dataset for emulator development that samples across four dimensions relevant to crop yields: atmospheric carbon dioxide (CO2) concentrations, temperature, water supply, and nitrogen inputs (CTWN). Simulations are run under two different adaptation assumptions: that growing seasons shorten in warmer climates, and that cultivar choice allows growing seasons to remain fixed. The dataset allows emulating the climatological-mean yield response of all models with a simple polynomial in mean growing-season values. Climatological-mean yields are a central metric in climate change impact analysis; we show here that they can be captured without relying on interannual variations. In general, emulation errors are negligible relative to differences across crop models or even across climate model scenarios; errors become significant only in some marginal lands where crops are not currently grown. We demonstrate that the resulting GGCMI emulators can reproduce yields under realistic future climate simulations, even though the GGCMI Phase 2 dataset is constructed with uniform CTWN offsets, suggesting that the effects of changes in temperature and precipitation distributions are small relative to those of changing means. The resulting emulators therefore capture relevant crop model responses in a lightweight, computationally tractable form, providing a tool that can facilitate model comparison, diagnosis of interacting factors affecting yields, and integrated assessment of climate impacts.

James A Franke↗