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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 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
NASA NTRS2011

SIERRA-Flux: Measuring Regional Surface Fluxes of Carbon Dioxide, Methane, and Water Vapor from an Unmanned Aircraft System

The Eddy-Covariance Method for quantifying surface-atmosphere fluxes is a foundational technique for measuring net ecosystem exchange and validating regional-to-global carbon cycle models. While towers or ships are the most frequent platform for measuring surface-atmosphere exchange, experiments using aircraft for flux measurements have yielded contributions to several large-scale studies including BOREAS, SMACEX, RECAB by providing local-to-regional coverage beyond towers. The low-altitude flight requirements make airborne flux measurements particularly dangerous and well suited for unmanned aircraft.

Fladeland↗
DOE OSTI2022

Systems and Implementation: Integrating Unmanned Aircraft Systems into Physical Protection Systems at Fixed Sites and During Transportation

Physical protection systems, and response forces in particular, are designed to prevent an adversary from successfully completing a malevolent act against a facility or transport operations. Timely detection and assessment of any potential adversary action against a target is an essential element of materials security. The timely detection and assessment must then be followed-up by a capable and timely response that might be enhanced with the additional situational awareness provided by unmanned aircraft systems (UAS). The United States Department of Energy’s National Nuclear Security Administration Office of International Nuclear Security has been exploring capabilities provided by UAS to support response force operations within the physical protection system. UAS have the potential to provide response force commanders and operators with situational awareness in assessing adversary locations and actions as well as the locations of responders. UAS may be utilized for area searches ahead of responder pathways to identify potential threats and to provide situational awareness of areas not normally covered by cameras (such as areas outside the fence line outside at fixed facilities). In addition, UAS can provide real-time information to transportation convoy teams that pass through constantly changing public access environments. This paper will provide operational recommendations to be addressed when integrating UAS into existing physical protection systems at fixed sites and during transport. Recommendations will include aspects of the following: needs analysis; tactics and techniques to support detection and assessment as well as response force deployment; remote pilot selection, qualifications, training, and currency; UAS selection criteria; UAS laws and regulations; possible cost sharing with other facility operations; and on-scene emergency management.

Stockwell, Brandon↗
NASA NTRS2020

Recent NASA Wind Tunnel Free-Flight Testing of a Multirotor Unmanned Aircraft System Vehicle

Wind tunnel free-flight tests of a small quadrotor vehicle were completed in the NASA Langley 12-Foot Low Speed Tunnel and 20-Foot Vertical Spin Tunnel. The primary objective of these tests was to acquire flight data in forward and descending flight for the purpose of assessing the fidelity of an all-attitude flight dynamics simulation previously developed from static and dynamic wind tunnel data. A secondary objective was to demonstrate and mature free-flight test methods specific to the emerging class of small unmanned aircraft and urban air mobility vehicles. Experimental flight data correlated well with simulation predictions which included steady trim conditions consistent with straight and level flight and quasi-steady conditions associated with descent velocities prone to vortex ring state development. The test method was shown to be well suited to these classes of vehicles and several unique infrastructure requirements, including tether systems and data acquisition requirements were identified. In addition, unique operational test techniques and safety procedures were developed to accommodate the testing. Results of these tests will be used to support air traffic management studies and research into safety assurance concepts that enable the integration of these classes of vehicles into the National Airspace System.

John V Foster↗
NASA NTRS2016

Lighter-Than-Air (LTA) "AirStation": Unmanned Aircraft System (UAS) Carrier Concept

Proposals for adapting modern airship technologies for military missions have mostly focused on exploiting the airships high flight endurance and low fuel requirement to conduct direct surveillance missions requiring high degrees of persistence over the areas to be observed. While this mission has value, it constrains the airship in two regards. (1) It places all the surveillance sensors, communication systems, and other mission equipment in the airship itself. (2) It requires the airship to be physically in the vicinity of the areas to be directly observed. A more advanced utilization of airship technology would be to add the capability to deploy a separate set of surveillance equipment, thereby enabling indirect and distributed observation operations. This can be undertaken by installing surveillance equipment in a squadron of unmanned aircraft systems (UAS) that can be carried and operated remotely from the airship, and then return to the airship as a base of support. This could be accomplished by deploying 20-30 UASs on an optionally manned (5 person crew) airship. The mission focus of the airship UAS carrier would be for support of distributed intelligence, surveillance and reconnaissance (ISR), close air support (CAS), maritime patrol and interdiction, electronic warfare (EW), persistent area dominance and missile defense. The logic for utilizing an airship carrier over a ground base to deploy UAS will be examined. Whether to be used as a stand-alone platform or in concert with conventional intelligence gathering techniques, the airship UAS carrier can provide the following benefits: a mobile base that will remain accessible despite political fallout which may render a ground base unavailable for use, the psychological impact of a power projection tool that has no geographical limits (imagined in the same way a naval carrier group projects power), cost-saving intelligence gathering over manned alternatives (assumption), and a wider area of influence when compared to an immobile ground base that must facilitate the transfer of UAS to other bases in order to overfly particular areas (all operations, launch, recover, etc. take place from the airship).

Hochstetler, Ron↗
NASA NTRS2012

NASA's UAS [Unmanned Aircraft Systems] Related Activities

NASA continues to operate all sizes of UAS in all classes of airspace both domestically and internationally. Missions range from highly complex operations in coordination with piloted aircraft, ground, and space systems in support of science objectives to single aircraft operations in support of aeronautics research. One such example is a scaled commercial transport aircraft being used to study recovery techniques due to large upsets. NASA's efforts to support routine UAS operations continued on several fronts last year. At the national level in the United States (U.S.), NASA continued its support of the UAS Executive Committee (ExCom) comprised of the Federal Aviation Administration (FAA), Department of Defense (DoD), Department of Homeland Security (DHS), and NASA. The committee was formed in recognition of the need of UAS operated by these agencies to access to the National Airspace System (NAS) to support operational, training, development and research requirements. Recommendations were received on how to operate both manned and unmanned aircraft in class D airspace and plans are being developed to validate and implement those recommendations. In addition the UAS ExCom has begun developing recommendations for how to achieve routine operations in remote areas as well as for small UAS operations in class G airspace. As well as supporting the UAS ExCom, NASA is a participant in the recently formed Aviation Rule Making Committee for UAS. This committee, established by the FAA, is intended to propose regulatory guidance which would enable routine civil UAS operations. As that effort matures NASA stands ready to supply the necessary technical expertise to help that committee achieve its objectives. By supporting both the UAS ExCom and UAS ARC, NASA is positioned to provide its technical expertise across the full spectrum of UAS airspace access related topic areas. The UAS NAS Access Project got underway this past year under the leadership of NASA s Aeronautics Research Mission Directorate. This project is focused on advancing the state of the art and providing research and analysis results in the areas of Separation Assurance, Communications (non-governmental spectrum allocation for UAS), Certification, and Human System Integration (ground control station design/pilot interfaces). The project is working in close coordination with the FAA and industry standards organizations (e.g. RTCA SC 203). More details on this project are provided in a separate article in this year's yearbook

Bauer, Jeffrey↗
NASA NTRS2016

The Pilatus Unmanned Aircraft System for Lower Atmospheric Research

This paper presents details of the University of Colorado (CU) "Pilatus" unmanned research aircraft, assembled to provide measurements of aerosols, radiation and thermodynamics in the lower troposphere. This aircraft has a wingspan of 3.2 m and a maximum take-off weight of 25 kg, and it is powered by an electric motor to reduce engine exhaust and concerns about carburetor icing. It carries instrumentation to make measurements of broadband up- and downwelling shortwave and longwave radiation, aerosol particle size distribution, atmospheric temperature, relative humidity and pressure and to collect video of flights for subsequent analysis of atmospheric conditions during flight. In order to make the shortwave radiation measurements, care was taken to carefully position a high-quality compact inertial measurement unit (IMU) and characterize the attitude of the aircraft and its orientation to the upward-looking radiation sensor. Using measurements from both of these sensors, a correction is applied to the raw radiometer measurements to correct for aircraft attitude and sensor tilt relative to the sun. The data acquisition system was designed from scratch based on a set of key driving requirements to accommodate the variety of sensors deployed. Initial test flights completed in Colorado provide promising results with measurements from the radiation sensors agreeing with those from a nearby surface site. Additionally, estimates of surface albedo from onboard sensors were consistent with local surface conditions, including melting snow and bright runway surface. Aerosol size distributions collected are internally consistent and have previously been shown to agree well with larger, surface-based instrumentation. Finally the atmospheric state measurements evolve as expected, with the near-surface atmosphere warming over time as the day goes on, and the atmospheric relative humidity decreasing with increased temperature. No directional bias on measured temperature, as might be expected due to uneven heating of the sensor housing over the course of a racetrack pattern, was detected. The results from these flights indicate that the CU Pilatus platform is capable of performing research-grade lower tropospheric measurement missions.

de Boer, Gijs↗
NASA NTRS2016

Assessing the Impact of Operational Constraints on the Near-Term Unmanned Aircraft System Traffic Management Supported Market

An economic impact market analysis was conducted for 16 leading sectors of commercial Unmanned Aerial System (UAS) applications predicted to be enabled by 2020 through the NASA UAS Traffic Management (UTM) program. Subject matter experts from seven industries were interviewed to validate concept of operations (ConOps) and market adoption assumptions for each sector. The market analysis was used to estimate direct economic impacts for each sector including serviceable addressable market, capital investment, revenue recovery potential, and operations cost savings. The resultant economic picture distinguishes the agricultural, pipeline and railroad inspection, construction, and maritime sectors of the nascent commercial UAS industry as providing the highest potential economic value in the United States. Sensitivity studies characterized the variability of select UAS sectors economic value to key regulatory or UTM ConOps requirements such as weight, altitude, and flight over populated area constraints. Takeaways from the analysis inform the validation of UTM requirements, technologies and timetables from a commercial market need and value viewpoint. This work concluded in August 2015 and reflects the state of the UAS industry and market projections at that time.

Air Traffic Management↗
NASA NTRS2016

Unmanned Aircraft System (UAS) Traffic Management (UTM): Enabling Civilian Low-Altitude Airspace and Unmanned Aerial System Operations

Just a year ago we laid out the UTM challenges and NASA's proposed solutions. During the past year NASA's goal continues to be to conduct research, development and testing to identify airspace operations requirements to enable large-scale visual and beyond visual line-of-sight UAS operations in the low-altitude airspace. Significant progress has been made, and NASA is continuing to move forward.

UTM↗
NASA NTRS2017

The Generic Resolution Advisor and Conflict Evaluator (GRACE) for Unmanned Aircraft Detect-And-Avoid Systems

The paper describes the Generic Resolution Advisor and Conflict Evaluator (GRACE), a novel alerting and guidance algorithm that combines flexibility, robustness, and computational efficiency. GRACE is generic since it was designed without any assumptions regarding temporal or spatial scales, aircraft performance, or its sensor and communication systems. Therefore, GRACE was adopted as a core component of the Java Architecture for Detect-And-Avoid (DAA) Extensibility and Modeling, developed by NASA as a research and modeling tool for Unmanned Aerial Systems Integration in the National Airspace System (NAS). GRACE has been used in a number of real-time and fast-time experiments supporting evolving requirements of DAA research, including parametric studies, NAS-wide simulations, human-in-the-loop experiments, and live flight tests.

Unmanned Aircraft↗