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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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

First look analyses of five cycles of ERTS-1 imagery over County of Los Angeles: Assessment of data utility for urban development and regional planning

Significant results have been obtained from the analyses of ERTS-1 imagery from five cycles over Test Site SR 124 by classical photointerpretation and by an interactive hybrid multispectral information extraction system (GEMS). The synopticity, periodicity and multispectrality of ERTS coverage, available for the first time to LA County planners, have opened up both a new dimensionality in data and offer new capability in preparation of planning inputs. Photointerpretation of ERTS images has produced over 25 overlays at 1:1,000,000 scale depicting regional relations and urban structure in terms of several hundred linear and areal features. To mention only one such result, a possible new fault lineament has been discovered on the northern slope of the Santa Monica mountains in the scene 1144-18015, composited of MSS bands 4, 5, 6,. GEMS analysis of the ERTS products has provided new or improved information in the following planning data categories: urban vegetation; land cover segregation; man-made and natural impact monitoring; urban design; and suitability. ERTS data analysis has allowed planners to establish trends that directly impact planning policies. This new source of information will not only assist current methods to be more efficient, but permits entirely new planning methodologies to be employed.

Raje, S.↗
NASA NTRS2003

The Urban Heat Island Phenomenon: How Its Effects Can Influence Environmental Decision Making in Your Community

Reinvestment in urban centers is breathing new life into neighborhoods that have been languishing as a result of explosive suburban development over the past several decades. In cities all over the country, adaptive reuse, brownfields redevelopment, transforming urban landscapes, economies, and quality of life. However, the way in which this development occurs has the potential to exacerbate the urban heat island (UHI) phenomenon, an existing problem in many areas and one which poses a threat to the long-term sustainability and environmental quality of cities. The UHI phenomenon is rooted in the science of how the land covers respond to solar heating and can adversely effect the environment. This phenomenon is responsible for urban centers having higher air temperatures and poorer air quality than suburban areas. In addition, the UHI phenomenon causes metrological occurrences, degrades water quality, increases energy demands, poses threats to public health and contributes to global warming. While the name of the phenomenon implies that is solely an urban issue, research has shown that the effects of the UHI are becoming prevalent in suburbs, as well. The UHI phenomenon can plague regions - urban centers and their suburbs. Furthermore, heat islands have been found to exist in both city centers and suburban communities. As suburban areas increasingly develop using land covers and building materials common to urban areas, they are inheriting urban problems - such as heat islands. In this way, it may be necessary for non-urban communities to engage in heat island mitigation. The good news is that through education and planning, the effects of the UHI phenomenon can be prevented and mitigated. Heat islands are more a product of urban design rather than the density of development. Therefore, cities can continue to grow and develop without exacerbating the UHI by employing sustainable development strategies.

Estes, Maurice G., Jr.↗
NASA NTRSDate not supplied

Aircraft Design Implications for Urban Air Mobility Vehicles Performing Public Good Missions

NASA has previously designed and described set of concept aircraft to serve as reference vehicles for Urban Air Mobility (UAM), to encourage public discussion and research. These vehicles are used in this paper to quantify how suitable UAM aircraft might be for missions other than their primary commercial design missions. A set of representative public good missions are described, along with design requirements and equipage. For two of these missions, the additional weight, power, and cost to facilitate a basic vehicle which may be built or configured with the ability to perform these missions is quantified. Special layout and other considerations which may impact vehicle design are described. For aircraft designed to the NASA UAM reference mission, the addition of some meaningful public good missions causes less than 10% growth in weight and power for fossil-fueled aircraft; advanced batteryelectric powered aircraft grow by a significantly larger amount and may only be possible with relaxed requirements. Meaningful public good missions with UAM vehicles are feasible, provided that public good mission requirements are considered and incorporated in the conceptual design stage of development.

Aircraft↗
NASA NTRS2018

Observations from Exploration of VTOL Urban Air Mobility Designs

NASA is exploring rotorcraft designs for VTOL air taxi operations, also known as urban air mobility (UAM) or on-demand mobility (ODM) applications. Several concept vehicles have been developed, intended to focus and guide NASA research activities in support of aircraft development for this emerging market. This paper summarizes the work conducted to date. To initially explore the broad design trade-space, three concept vehicles were designed: a quadrotor with electric propulsion; a side-by-side helicopter with hybrid propulsion; and a tiltwing with turbo-electric propulsion. Next a specific UAM mission was developed, accounting for the existing geography, population patterns, infrastructure, and weather in twenty-eight markets across the United States of America. Then in order to quantify the tradeoffs and performance targets necessary for practical implementation of the UAM vision, aircraft were designed to perform this mission, considering a range of aircraft types and propulsion system architectures: quadrotor aircraft, with turboshaft and all-electric propulsion; side-by-side aircraft, with turboshaft and all-electric propulsion; and lift+cruise aircraft with all-electric and turbo-electric propulsion. In examining these vehicles, performance targets and recurring technology themes emerged, which can guide investments in research and development within NASA, other government agencies, academia, and industry. In addition, results from the designs support observations about the trade-offs and key design decisions.

Observations from Exploration↗
NASA NTRSDate not supplied

Mechanical Design of the Urban Air Mobility Side-by-Side Test Stand

The Urban Air Mobility Side-by-Side Test Stand (SBS) is a new capability for the National Aeronautics and Space Administration (NASA) to test the conceptual side-by-side rotorcraft configuration. This test stand enhances the experimental capabilities of the Revolutionary Vertical Lift Technology (RVLT) Project and is primarily designed to be tested in the U.S. Army’s 7-by 10-Foot Wind Tunnel at NASA Ames Research Center. One of the goals for the SBS is to identify the optimal degree of rotor overlap that will yield the best aerodynamic performance. The SBS has two counter-rotating, intermeshing rotors that can vary in lateral separation. The test stand can pitch nose up and nose down, with each rotor having the capability to be trimmed independently through cyclic and collective controls. Six-axis load cells and rotary torque sensors are placed underneath each rotor to measure the thrust, torque, and side force from each rotor system. This paper describes the mechanical design of the SBS and outlines the structural analyses conducted to ensure a safety factor of 4 for ultimate strength and 3 for yield strength during all experimental testing.

Mechanical Design↗
DOE OSTI2024

Leveraging generative AI for urban digital twins: a scoping review on the autonomous generation of urban data, scenarios, designs, and 3D city models for smart city advancement

The digital transformation of modern cities by integrating advanced information, communication, and computing technologies has marked the epoch of data-driven smart city applications for efficient and sustainable urban management. Despite their effectiveness, these applications often rely on massive amounts of high-dimensional and multi-domain data for monitoring and characterizing different urban sub-systems, presenting challenges in application areas that are limited by data quality and availability, as well as costly efforts for generating urban scenarios and design alternatives. As an emerging research area in deep learning, Generative Artificial Intelligence (GenAI) models have demonstrated their unique values in content generation. This paper aims to explore the innovative integration of GenAI techniques and urban digital twins to address challenges in the planning and management of built environments with focuses on various urban sub-systems, such as transportation, energy, water, and building and infrastructure. The survey starts with the introduction of cutting-edge generative AI models, such as the Generative Adversarial Networks (GAN), Variational Autoencoders (VAEs), Generative Pre-trained Transformer (GPT), followed by a scoping review of the existing urban science applications that leverage the intelligent and autonomous capability of these techniques to facilitate the research, operations, and management of critical urban subsystems, as well as the holistic planning and design of the built environment. Based on the review, we discuss potential opportunities and technical strategies that integrate GenAI models into the next-generation urban digital twins for more intelligent, scalable, and automated smart city development and management.

3D city modeling↗
NASA NTRS2018

Observations from Exploration of VTOL Urban Air Mobility Designs

This presentation will be displayed on the Aeromechanics Branch website. It outlines: NASA Exploration of Urban Air Mobility, Reduced-Emission Rotorcraft Concepts, Concept Vehicles for Air Taxi Operations, Vehicles for UAM Mission and Market and Observations.

Urban Air Mobility Designs↗
NASA NTRSDate not supplied

On the Modeling of Urban Air Mobility Vehicle Takeoff and Landing Operations in the FAA Aviation Environmental Design Tool

Urban air mobility (UAM) vehicles are anticipated to operate in close proximity to the public. A possible barrier to the introduction of UAM vehicles as a transit solution is their community noise impact, particularly around vertiports. The Federal Aviation Administration Aviation Environmental Design Tool (AEDT) is the mandated tool to assess aircraft noise and other environmental impacts due to federal actions at civilian airports, vertiports, or in U.S. airspace for commercial flight operations. However, AEDT was designed to model fixed-wing aircraft and conventional helicopter operations, not UAM vehicles. Prior work by the authors showed significant differences in noise contours of UAM departures and approaches when modeling operations as fixed-wing and helicopter types in AEDT. This paper identifies the sources of those differences. Additionally, a NASA time-marching simulation tool is used to generate noise exposure predictions for equivalent operations to help identify differences associated with the noise model implemented in AEDT and offer possible changes to assess UAM community noise impact more consistently with simulation-based modeling.

aeroacoustics↗
NASA NTRSDate not supplied

On the Modeling of Urban Air Mobility Vehicle Takeoff and Landing Operations in the FAA Aviation Environmental Design Tool

Urban air mobility (UAM) vehicles are anticipated to operate in close proximity to the public. A possible barrier to the introduction of UAM vehicles as a transit solution is their community noise impact, particularly around vertiports. The Federal Aviation Administration Aviation Environmental Design Tool (AEDT) is the mandated tool to assess aircraft noise and other environmental impacts due to federal actions at civilian airports, vertiports, or in U.S. airspace for commercial flight operations. However, AEDT was designed to model fixed-wing aircraft and conventional helicopter operations, not UAM vehicles. Prior work by the authors showed significant differences in noise contours of UAM departures and approaches when modeling operations as fixed-wing and helicopter types in AEDT. This paper identifies the sources of those differences. Additionally, a NASA time-marching simulation tool is used to generate noise exposure predictions for equivalent operations to help identify differences associated with the noise model implemented in AEDT and offer possible changes to assess UAM community noise impact more consistently with simulation-based modeling.

aeroacoustics↗
NASA NTRSDate not supplied

Guidance for Designing Safety into Urban Air Mobility: Hazard Analysis Techniques

The national airspace system is exceptionally safe, specifically in terms of commercial air traffic operations. The introduction of innovative aircraft (such as electric vertical takeoff and landing vehicles) undergoing novel operations (such as for an urban air passenger carrying mission) is a potential disruptor to the current means of regulating and ensuring the safety of air travel. The aviation industry and associated regulatory bodies are adapting their approaches to assuring system safety to enable these new paradigms. However, any system safety analysis requires that a hazard assessment be performed. In this work, we consider the Functional Hazard Assessment (FHA) and Systems Theoretic Process Analysis (STPA) techniques for hazard assessment and evaluate whether they can be used in a complementary fashion for regulatory approval purposes. We perform an FHA and an STPA on an electric vertical takeoff and landing (eVTOL) vehicle undergoing an urban air mobility (UAM) passenger carrying reference scenario and present excerpts of this analysis. We then draw parallels between the techniques and highlight elements where they naturally reinforce to each other’s results, specifically in the consideration of hazard severity with respect to flight phases, the design of hazard mitigations, and the applicability of the results to all types of regulatory approvals (e.g., type certification, operational approval, and crew training).

Mallory S Graydon↗
NASA NTRS2020

In-time System-wide Safety Assurance (ISSA) Concept of Operations and Design Considerations for Urban Air Mobility (UAM)

Emerging operations involving Advanced Air Mobility (AAM), such as Urban Air Mobility (UAM), pose a challenge to safety assurance and to accessibility within the National Airspace System (NAS).In particular, the public has a low tolerance for risk in aviation and the current NAS tends to be labor-intensive with limited ability to scale up for UAM. In response to this landscape, NASA is collaborating with industry to define a Concept of Operations (ConOps) for In-time System-Wide Safety Assurance (ISSA) for scalable UAM involving a service-oriented architecture. This architecture focuses safety investments for technological solutions that can overcome safety related barriers for emerging operations. By working with industry, consensus can be reached on desirable system traits that are based on integration and fusion of data and leverage increasingly autonomous and automated systems. These complex systems can identify anomalies, precursors, and trends that together enable more proactive management of operational risks. AAM and UAM elevate the need for risk management in relation to increasing density and heterogeneity of vehicles and operations. Whereas safety in today’s NAS is built on a history of programs and technologies that react to incidents and accidents, AAM presents an opportunity to leverage that experience and its implications and proactively integrate safety into the earliest designs of vehicles and systems. In a perfect world AAM and UAM would not be inherently dangerous but until then ensuring the highest quality of safety requirements is the bridge to mitigating risks.

In-Time System-Wide Safety Assurance↗
NASA NTRSDate not supplied

Designing A Coaxial Quadrotor for Urban Air Mobility

The NASA Revolutionary Vertical Lift Technology Project has created several Urban Air Mobility reference design vehicles to aid the burgeoning UAM industry. With over 700 conceptual designs already proposed, much interest has been generated across many unique configurations to bring vertical flight to the masses. The quadrotor configuration is one of the NASA reference vehicles, and does have some conceptual designs proposed in the industry. This study looks at the conceptual design of a coaxial quadrotor vehicle as an extension of the NASA RVLT quadrotor concept vehicle. The coaxial quadrotor has a similar layout to the quadrotor, but with a coaxial rotor at each of the four corners of the vehicle. Trade studies carried out using the NASA Design and Analysis of Rotorcraft (NDARC) tool analyzed the vehicle sizing, design gross weight, and performance for four design variants. The variants all use the baseline coaxial quadrotor layout, but analyze the effects of two major design choices: 1) variable pitch vs variable speed rotor control, and 2) motor to rotor power transmission via a gearbox vs direct-drive. The results indicate one design variant may have more benefits on some of the design objectives while another configuration may better satisfy the others.

UAM↗
NASA NTRSDate not supplied

Urban Air Mobility Fleet Manager Gap Analysis and System Design

NASA’s Urban Air Mobility (UAM) Sub-Project is engaged in re-search to facilitate the introduction of air taxis into the US National Airspace System. Given the history of conventional aircraft operations, it is clear that dispatcher support will be required for UAM. This paper presents a gap analysis, system requirements, and a workstation design concept for the UAM dispatcher or Fleet Manager (FM) position. The gap analysis focuses on the differences be-tween the tasks of the airline dispatcher and those projected for the FM. FM system capabilities and data requirements are then presented as foundations for soft-ware development. An initial user interface concept is provided. The FM software uses a single, large display. The system supports prediction, monitoring, and task execution. This paper is intended to support FM software design for future air taxi systems.

Richard Mogford↗
NASA NTRS2019

Urban Air Mobility Fleet Manager Gap Analysis and System Design

NASA's Urban Air Mobility (UAM) Sub-Project is engaged in research to support the introduction of air taxis into the National Airspace System. Such operations will require a range of communication, navigation, and surveillance systems. Air vehicles for UAM are under development and will initially have human pilots. Separation from other aircraft, obstacles, and weather may be a pilot responsibility or provided by an operator's ground-based systems. Eventually, air taxis may be flown from the ground or fly autonomously. There will be a need for dispatch services for UAM. This report presents a gap analysis, data and capability requirements, and workstation design concepts for the UAM dispatcher or Fleet Manager (FM) position.

Mogford, Richard↗
DOE OSTI2020

URBANopt: An Open-Source Software Development Kit for Community and Urban District Energy Modeling: Preprint

Urban building modeling tools are developing rapidly; these tools use emerging simulation workflows for specific urban environmental design tasks, such as assessing the impacts of energy efficiency technologies at a district scale. However, with the emergence of new environmental design tasks, addressing all possible use cases and tasks is challenging and cannot be covered by a single tool. Urban-scale analysis at this level of complexity often requires linking multiple emerging tools, rather than using a single tool, to adequately evaluate a variety of possible fields in urban environmental design. To achieve this, flexible platforms are needed to support multiple input formats (e.g., geometric and non-geometric building properties), enabling the mapping of such inputs to underlying simulation engines. This paper provides an overview of the open-source URBANopt Software Development Kit (SDK) for modeling high-performance buildings and energy systems at a district scale. URBANopt's flexible SDK is composed of several modules that can be customized to integrate with other tools and generate new workflows to perform urban environmental design tasks, such as capturing interactions between individual buildings, district energy systems, distributed energy resources, and the electric distribution grid. We describe the functionality of the core SDK modules in URBANopt (called Core Gem, GeoJSON Gem, and Scenario Gem) and discuss the flexibility of these modules as a means of integration with a variety of tools. We also document and demonstrate technical details of writing and combining new modules to create customized workflows. Finally, we present a case study that uses the URBANopt SDK to model a hypothetical mixed-use urban project and simulate various scenarios to meet district energy performance goals.

buildings↗
NASA NTRSDate not supplied

Conceptual Design of Tiltrotor Aircraft for Urban Air Mobility

There has been an abundance of new and novel aircraft designs created for Urban Air Mobility (UAM) in recent years. The National Aeronautics and Space Administration (NASA) contributes to the research and development of this industry in part by applying its aircraft design tools to create conceptual designs of UAM reference vehicles. The vehicles are intended to quantify the tradeoffs and performance capabilities necessary for VTOL (vertical takeoff and landing) aircraft in the UAM design space. The reference vehicles represent a variety of configurations that seek to encompass many of the design characteristics suitable for UAM. This work focuses on the conceptual design process of two new NASA reference vehicles. Both aircraft are configured as conventional tiltrotors, but one is powered by turboshaft engines, and one is fully electric. The sizing and performance of the two aircraft are discussed, as well as how the performance and characteristics compare to a selection of other NASA reference vehicles. It is found that the tiltrotor configuration is capable of reaching speeds 43% to 51% faster than the other turboshaft designs, and 54% to 93% faster than the other electric designs. The increased speed leads to a 24% to 42% decrease in overall mission time.

Conceptual Design↗