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All sourcesNASA NTRSDOE OSTI
NASA NTRS2019

Fast-Time Simulation for Evaluating the Impact of Estimated Flight Ready Time Uncertainty on Surface Metering

NASA has been developing and demonstrating new concepts and technologies for Integrated Arrival, Departure, and Surface (IADS) traffic management capabilities under the Airspace Technology Demonstration 2 (ATD-2) project. One of the IADS capabilities in the ATD-2 project is surface metering enabled by a tactical surface scheduler to provide controllers with the pushback advisories for departures at gates. The tactical surface scheduler uses the estimated flight ready times provided by airlines, called Earliest Off-Block Times (EOBTs), as input to calculate the target off-block times for pushback advisories. However, the EOBTs are often inaccurate and deviate from the actual flight ready times, which may reduce the benefits of surface metering. In this paper, a linear regression model is developed to model the EOBT uncertainty distribution over time based on actual EOBT data collected at Charlotte airport. This EOBT model is integrated with a tactical surface scheduler and a fast-time simulation tool. To evaluate the impact of the EOBT accuracy on airport surface operations, fast-time simulations are implemented for selected traffic scenarios under different levels of modelled EOBT accuracy. The simulation results show that the EOBT uncertainty affects several performance metrics related to the surface metering, such as gate hold, taxi time reduction, and target takeoff time predictability, which in turn influences ATD-2's scheduler performance.

tactical surface scheduler↗
NASA NTRS1988

The use of available potential energy to evaluate the impact of satellite data on numerical model analysis during FGGE

To evaluate the effect of the FGGE satellite observing system, the following two data sets were compared by examining the available potential energy (APE) and extratropical cyclone activity within the entire global domain during the first Special Observing Period: (1) the complete FGGE IIIb set, which incorporates satellite soundings, and (2) a NOSAT set which incorporates only conventional data. The time series of the daily total APEs indicate that NOSAT values are larger than the FGGE values, although in the Northern Hemisphere the differences are negligible. Analyses of cyclone scale features revealed only minor differences between the Northern Hemisphere FGGE and NOSAT analyses. On the other hand, substantial differences were revealed in the two Southern Hemisphere analyses, where the satellite soundings apparently add detail to the FGGE set.

Horn, Lyle H.↗
NASA NTRS2012

The SPoRT-WRF: Evaluating the Impact of NASA Datasets on Convective Forecasts

The Short-term Prediction Research and Transition Center (SPoRT) is a collaborative partnership between NASA and operational forecasting entities, including a number of National Weather Service offices. SPoRT transitions real-time NASA products and capabilities to its partners to address specific operational forecast challenges. One challenge that forecasters face is applying convection-allowing numerical models to predict mesoscale convective weather. In order to address this specific forecast challenge, SPoRT produces real-time mesoscale model forecasts using the Weather Research and Forecasting (WRF) model that includes unique NASA products and capabilities. Currently, the SPoRT configuration of the WRF model (SPoRT-WRF) incorporates the 4-km Land Information System (LIS) land surface data, 1-km SPoRT sea surface temperature analysis and 1-km Moderate resolution Imaging Spectroradiometer (MODIS) greenness vegetation fraction (GVF) analysis, and retrieved thermodynamic profiles from the Atmospheric Infrared Sounder (AIRS). The LIS, SST, and GVF data are all integrated into the SPoRT-WRF through adjustments to the initial and boundary conditions, and the AIRS data are assimilated into a 9-hour SPoRT WRF forecast each day at 0900 UTC. This study dissects the overall impact of the NASA datasets and the individual surface and atmospheric component datasets on daily mesoscale forecasts. A case study covering the super tornado outbreak across the Ce ntral and Southeastern United States during 25-27 April 2011 is examined. Three different forecasts are analyzed including the SPoRT-WRF (NASA surface and atmospheric data), the SPoRT WRF without AIRS (NASA surface data only), and the operational National Severe Storms Laboratory (NSSL) WRF (control with no NASA data). The forecasts are compared qualitatively by examining simulated versus observed radar reflectivity. Differences between the simulated reflectivity are further investigated using convective parameters along with model soundings to determine the impacts of the various NASA datasets. Additionally, quantitative evaluation of select meteorological parameters is performed using the Meteorological Evaluation Tools model verification package to compare forecasts to in situ surface and upper air observations.

Zavodsky, Bradley↗
NASA NTRS2005

Wake Vortex Advisory System (WakeVAS) Evaluation of Impacts on the National Airspace System

This report is one of a series that describes an ongoing effort in high-fidelity modeling/simulation, evaluation and analysis of the benefits and performance metrics of the Wake Vortex Advisory System (WakeVAS) Concept of Operations being developed as part of the Virtual Airspace Modeling and Simulation (VAMS) project. A previous study, determined the overall increases in runway arrival rates that could be achieved at 12 selected airports due to WakeVAS reduced aircraft spacing under Instrument Meteorological Conditions. This study builds on the previous work to evaluate the NAS wide impacts of equipping various numbers of airports with WakeVAS. A queuing network model of the National Airspace System, built by the Logistics Management Institute, Mclean, VA, for NASA (LMINET) was used to estimate the reduction in delay that could be achieved by using WakeVAS under non-visual meteorological conditions for the projected air traffic demand in 2010. The results from LMINET were used to estimate the total annual delay reduction that could be achieved and from this, an estimate of the air carrier variable operating cost saving was made.

Smith, Jeremy C.↗
NASA NTRS2024

An Approach to Evaluating the Impact of Small-Core Turbofan Technologies on Engine and Aircraft Performance

NASA’s Hybrid Thermally Efficient Core (HyTEC) project aims to accelerate the development of small-core turbofan engine technologies to enable a fuel burn reduction of 5 to 10 percent for next-generation aircraft, compared to 2020s best-in-class technology. This paper presents a demonstration of methods for evaluating the potential performance impact of small-core engine technologies developed under Phase 1 of the HyTEC project. The approach involves model-based systems analysis, where small-core innovations are integrated into baseline turbofan and aircraft systems models, creating a notional vision system. Performance of the vision system is examined at both the engine and vehicle level. The examined performance metrics include: engine bypass ratio, overall pressure ratio, high pressure compressor exit corrected mass flow, and aircraft fuel burn. The CFM LEAP-1B28 and Boeing 737 MAX 8 are chosen as the baseline state-of-the-art systems. Preliminary results map a design space for the small-core vision system and quantify the distinct effects of technologies on the key metrics.

Michael A Bennett↗
NASA NTRSDate not supplied

An Approach to Evaluating the Impact of Small-core Turbofan Technologies on Engine and Aircraft Performance

NASA’s Hybrid Thermally Efficient Core (HyTEC) project aims to accelerate the development of small-core turbofan engine technologies to enable a fuel burn reduction of 5 to 10 percent for next-generation aircraft, compared to 2020s best-in-class technology. This paper presents a demonstration of methods for evaluating the potential performance impact of small-core engine technologies developed under Phase 1 of the HyTEC project. The approach involves model-based systems analysis, where small-core innovations are integrated into baseline turbofan and aircraft systems models, creating a notional vision system. Performance of the vision system is examined at both the engine and vehicle level. The examined performance metrics include: engine bypass ratio, overall pressure ratio, high pressure compressor exit corrected mass flow, and aircraft fuel burn. The CFM LEAP-1B28 and Boeing 737 MAX 8 are chosen as the baseline state-of-the-art systems. Preliminary results map a design space for the small-core vision system and quantify the distinct effects of technologies on the key metrics.

Michael Bennett↗
NASA NTRS1979

The role of rim slumping in the modification of lunar impact craters

The role of rim slumping in the formation of terraces on interior crater walls and consequent modifications of the shapes of large lunar impact craters is evaluated. Impact excavation cavities were reconstructed by means of a terrace restoration model for twelve lunar craters ranging in diameter from 19 to 137 km. For craters up to 30 km, reconstructed cavity depths are comparable to or greater than cavity depths extrapolated from nonterraced smaller craters, and in the 30 to 70 km diameter range, the reconstructed cavity depths are significantly greater. For craters larger than 70 km, however, the reconstructed cavity depths are consistently less than those predicted from small crater morphometry, indicating a significant additional contribution from ejecta fallback and basement rebound to the modification of the shape of impact craters greater than 70 km.

Settle, M.↗
NASA NTRS2021

Evaluating the Impact of Model Resolutions and Cumulus Parameterization on Precipitation in NU-WRF: A Case Study in the Central Great Plains

Regional climate models are expected to exhibit improved skill at finer spatial resolutions due to improved representation of land surface heterogeneity. However, at spatial scales between 1 to 10 km (grey scales), these improvements are often illusive due to the competing benefits from spatial resolution and cumulus parameterization. This study provides insights into the impact of model resolution and cumulus parameterization on precipitation prediction in the Central Great Plains by using an object-based evaluation method. Our results show limited improvement solely from finer resolution but larger improvement without using the cumulus scheme at a 4-kmresolution. Compared to traditional evaluation methods, the object-based analysis shows that without the cumulus scheme the spatial properties of precipitation are better represented. In contrast, all model configurations show a dry bias in precipitation days and a tendency to produce widespread precipitation but with fewer hours with precipitationwhich indicates other shortcomings in the model.

Yuqi Zhang↗
NASA NTRS1976

High pressure liquid and gaseous oxygen impact sensitivity evaluation of materials for use at Kennedy Space Center

The sensitivity of materials in contact with gaseous oxygen (GOX) or liquid oxygen (LOX) was examined. Specifically, the reactivity of materials when in contact with GOX or LOX if subjected to such stimuli as mechanical impact, adiabatic compression (pneumatic impact), or an electrical discharge in the form of a spark were examined. Generally, materials are more sensitive in gaseous oxygen than in liquid oxygen and impact sensitivity is known to increase with increasing pressure. Materials presently being used or considered for use in oxygen systems at KSC were evaluated. Results are given in tabular form.

Bryan, C. J.↗
NASA NTRS1991

Lessons from cross-fleet/cross-airline observations - Evaluating the impact of CRM/LOFT training

A review is presented of the crew resource management/line oriented flight training (CRM/LOFT) program to help determine the level of standardization across fleets and airlines in the critical area of evaluating crew behavior and performance. One of the goals of the project is to verify that check airmen and LOFT instructors within organizations are evaluating CRM issues consistently and that differences observed between fleets are not a function of idiosyncracies on the part of observers. Attention is given to the research tools for crew evaluation.

Butler, Roy E.↗
NASA NTRS2022

Evaluating the Impact of Chemical Complexity and Horizontal Resolution on Tropospheric Ozone Over the Conterminous US With a Global Variable Resolution Chemistry Model

A new configuration of the Community Earth System Model (CESM)/Community Atmosphere Model with full chemistry (CAM-chem) supporting the capability of horizontal mesh refinement through the use of the spectral element (SE) dynamical core is developed and called CESM/CAM-chem-SE. Horizontal mesh refinement in CESM/CAM-chem-SE is unique and novel in that pollutants such as ozone are accurately represented at human exposure relevant scales while also directly including global feedbacks. CESM/CAM-chem-SE with mesh refinement down to ∼14 km over the conterminous US (CONUS) is the beginning of the Multi-Scale Infrastructure for Chemistry and Aerosols (MUSICAv0). Here MUSICAv0 is evaluated and used to better understand how horizontal resolution and chemical complexity impact ozone and ozone precursors over CONUS as compared to measurements from five aircraft campaigns, which occurred in 2013. This field campaign analysis demonstrates the importance of using finer horizontal resolution to accurately simulate ozone precursors such as nitrogen oxides and carbon monoxide. In general, the impact of using more complex chemistry on ozone and other oxidation products is more pronounced when using finer horizontal resolution where a larger number of chemical regimes are resolved. Large model biases for ozone near the surface remain in the Southeast US as compared to the aircraft observations even with updated chemistry and finer horizontal resolution. This suggests a need for adding the capability of replacing sections of global emission inventories with regional inventories, increasing the vertical resolution in the planetary boundary layer, and reducing model biases in meteorological variables such as temperature and clouds.

MUSICA↗
NASA NTRS2009

A Combination of Traditional and Novel Methods Used to Evaluate the Impact of an EVA Glove on Hand Performance

The gloved hand is an astronaut s primary means of interacting with the environment, so performance on an EVA is strongly impacted by any restrictions imposed by the glove. As a result, these restrictions have been the subject of study for decades. However, previous studies have generally been unsuccessful in quantifying glove mobility and tactility. Instead, studies have tended to focus on the dexterity, strength and functional performance of the gloved hand. Therefore, it has been difficult to judge the impact of each type of restriction on the glove s overall capability. The lack of basic information on glove mobility in particular, is related to the difficulty in instrumenting a gloved hand to allow an accurate evaluation. However, the current study aims at developing novel technological capabilities to provide metrics for mobility and tactility that can be used to assess the performance of a glove in a way that could enable designers and engineers to improve upon their current designs. A series of evaluations were performed in ungloved, unpressurized and pressurized (4.3 psi) conditions, to allow a comparison across pressures and to the baseline barehanded condition. In addition, a subset of the testing was also performed with the Thermal Micrometeoroid Garment (TMG) removed. This test case in particular provided some interesting insight into how much of an impact the TMG has on gloved mobility -- in some cases, as much as pressurization of the glove. Previous rule-of-thumb estimates had assumed that the TMG would have a much lower impact on mobility, while these results suggest that an improvement in the TMG could actually have a significant impact on glove performance. Similarly, tactility testing illustrated the impact of glove pressurization on tactility and provided insight on the design of interfaces to the glove. The metrics described in this paper have been used to benchmark the Phase VI EVA glove and to develop requirements for the next generation glove for the Constellation program.

Rajulu, Sudhakar↗
NASA NTRS2016

Evaluating the Impact of Data Placement to Spark and SciDB with an Earth Science Use Case

We investigate the impact of data placement for two Big Data technologies, Spark and SciDB, with a use case from Earth Science where data arrays are multidimensional. Simultaneously, this investigation provides an opportunity to evaluate the performance of the technologies involved. Two datastores, HDFS and Cassandra, are used with Spark for our comparison. It is found that Spark with Cassandra performs better than with HDFS, but SciDB performs better yet than Spark with either datastore. The investigation also underscores the value of having data aligned for the most common analysis scenarios in advance on a shared nothing architecture. Otherwise, repartitioning needs to be carried out on the fly, degrading overall performance.

Spark↗
NASA NTRS2019

Evaluation of Impact Energy Attenuators and Composite Material Designs of a UAM VTOL Concept Vehicle

The development of Vertical Take-off and Landing (VTOL) vehicles for the Urban Air Mobility (UAM) markets presents a need for light weight vehicle structures with effective occupant protection capabilities. The National Aeronautics and Space Administration (NASA) has been working to fill that need, recently developing a cadre of concept vehicles to help characterize UAM design feasibility. This paper describes a study, using these concept vehicles, to evaluate the use of advanced composite structure and energy attenuating designs in the UAM vehicle design space. A finite element model (FEM) of a single passenger quadrotor concept vehicle was developed in LS-Dyna® and simulated under nominal and off-nominal vertical impact conditions. A variety of energy attenuating design mechanisms were implemented within this model to quantify their effectiveness in improving occupant safety. The use of carbon composites in both the energy attenuation mechanisms and vehicle structure was evaluated. The results of this study found significant reduction in occupant injury risk with the implementation of energy absorbing composite crush tubes and landing gear within the vehicle design. Additionally the use of a carbon fiber as a structural material was found to provide significant weight reduction while maintaining similar occupant loads to that predicted with an aluminum structure. This work provides a preliminary evaluation of design mechanisms and materials that may be used to optimize occupant protection capabilities within the UAM market.

Putnam, Jacob↗
NASA NTRSDate not supplied

Evaluating the Impact of Agricultural Soil NOx Emissions on Air Quality Using Advanced Satellite, Ground-based, and Model Data

Soil moisture can also influence the concentration of atmospheric trace gases by moderating the emission of nitrogen oxides (NOx = NO + NO2) from agricultural fields. Human activities can play an important role in controlling the available soil moisture depending on irrigation demand and agricultural management. To further complicate matters, nitrogen fertilizer use has also been found to be a significant source of NOx emissions in agricultural areas. In fact, some of the highest emissions have been reported from fertilized soils in high-temperature agricultural regions, such as the Imperial Valley of California. Since NO2 is an important precursor to ozone formation in the troposphere, which is a leading cause of premature death in humans, it is critical to understand how natural and anthropogenic factors contribute to NOx emissions in these areas. O3 pollution is also a growing threat to global food security due to its detrimental impacts on crop production. This work uses a suite of satellite, ground-based, and model data to investigate how agricultural soil NOx emissions from natural (rainfall) and anthropogenic factors (irrigation, nitrogen fertilizer) govern air quality over California. We evaluate the capabilities of using SMAP retrievals and SMAP Land Information System (LIS) output for monitoring irrigation activities over the major agricultural areas of California by conducting intensive analyses of soil moisture and precipitation data. High-resolution trace gas observations from the new generation TROPOspheric Monitoring Instrument (TROPOMI) sensor are used to characterize and monitor the variability of trace gases and air quality conditions associated with soil NOx emissions. We also synthesize satellite, ground-based, and agriculture data to estimate the separate contributions from rainfall, irrigation, and nitrogen fertilizer practices on soil NOx emissions and associated air quality conditions. Finally, unprecedented hourly trace gas retrievals from the NASA Tropospheric Emissions: Monitoring of Pollution (TEMPO) geostationary satellite sensor are used to monitor the diurnal evolution of NO2 and O3 concentrations from soil NOx emissions.

Aaron R Naeger↗
NASA NTRSDate not supplied

SimUAM: A Comprehensive Microsimulation Toolchain to Evaluate the Impact of Urban Air Mobility in Metropolitan Areas

Over the past several years, Urban Air Mobility (UAM) has galvanized enthusiasm from investors and researchers, marrying expertise in aircraft design, transportation, logistics, artificial intelligence, battery chemistry, and broader policymaking. However, two significant questions remain unexplored: (1) What is the value of UAM in a region’s transportation network? and (2) How can UAM be effectively deployed to realize and maximize this value to all stakeholders, including riders and local economies? To adequately understand the value proposition of UAM for metropolitan areas, the authors develop a holistic multi-modal toolchain, SimUAM, to model and simulate UAM and its impacts on travel behavior. This toolchain has several components: (1) Microsimulation Analysis for Network Traffic Assignment (MANTA): A fast, high-fidelity regional-scale traffic microsimulator, (2) VertiSim: Agranular, discrete-event vertiport and pedestrian simulator, (3) Flexible Engine for Fast-time Evaluation of Flight Environments (Fe3): A high-fidelity, trajectory-based aerial microsimulation. SimUAM, rooted in granular, GPU-based microsimulation, models millions of trips and their movements in the street network and in the air, producing interpretable and actionable performance metrics for UAM designs and deployments. Once the ground-air interface is modeled, the authors find that the market for UAM decreases across all network designs relative to models with static assumptions about transfer times. However, significant improvements can be made to balance the demand and optimize the networks for transfer time, likely increasing the number of benefited trips. The modularity, extensibility, and speed of the platform will allow for rapid scenario planning and sensitivity analysis, effectively acting as a detailed performance assessment tool.

urban air mobility↗
NASA NTRS1990

Image correlation nondestructive evaluation of impact damage in a glass fiber composite

Presented in viewgraph format, digital image correlation, damage in fibrous composites, and damaged coupons (cross-ply scotchply GI-Ep laminate) are outlined. It was concluded that the image correlation accuracy was 0.03 percent; strains can be processed through Tsai-Hill failure criteria to qualify the damage; the statistical data base must be generated to evaluate certainty of the damage estimate; size effects need consideration; and better numerical techniques are needed.

Russell, Samuel S.↗
NASA NTRSDate not supplied

Evaluating GXS Impact in the Context of International Coordination

The proposed NOAA/NASA Geostationary eXtended Observations (GeoXO) program plans to include a hyperspectral infrared (IR) sounder on its central satellite. Expected to launch in the mid-2030s, the GeoXO Sounder (GXS) will join international counterparts in a geostationary orbit. Ahead of launch, the NASA Global Modeling and Assimilation Office (GMAO) assessed the potential effectiveness of GXS both as a single GEO IR sounder and as part of a global ring of such instruments, including those already being built by international agencies. Using an observing system simulation experiment (OSSE) framework, GXS was assessed from a global numerical weather prediction (NWP) perspective. The ability of GXS, both alone and as part of a global ring of GEO sounders, to improve weather prediction of thermodynamic variables was evaluated globally and regionally. Compared to a control, GXS dominated regional analysis and forecast improvements, and contributed significantly to global increases in forecast skill. However, more sustained global improvements on the order of 4 days rely on international partnerships. Using the FSOI metric over CONUS, the GXS observations provide the strongest radiance impact on the moist energy error norm reduction. Additionally, GXS shows the capability to improve hurricane forecast track errors, resulting in improved forecast warnings. Overall, the persistent atmospheric profile information from GXS over much of the western hemisphere provide an opportunity to improve the representation of weather systems and their forecasts.

Erica McGrath-Spangler↗