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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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1,468 records · Page 82
All sourcesNASA NTRSDOE OSTI
NASA NTRS2024

Platte River Water Resources: Assessing Urban Flood Vulnerability to Select Restoration Sites for Urban Woods and Prairies in the Great Plains

In the Platte River Basin, wetlands provide ecosystem services such as flood mitigation and wildlife habitat. However, increasing urban development in the area has impacted natural floodplain processes, leading to a decline in wildlife habitat and an elevated flood risk for nearby communities. To address this issue, Audubon Great Plains’ Urban Woods and Prairies (UWP) Initiative focuses on restoring vital habitats within urban areas to protect bird species and reduce flood hazards. Our project used remotely sensed data, including Landsat 8 Operational Land Imagery (OLI), Sentinel-2 Multispectral Instrument (MSI), and Sentinel-1 Synthetic Aperture Radar (SAR), to assess land use and land cover from 2013 to 2023, as well as flood extent. Broad-scale analysis of the LULC showed some changes in land use patterns across the Central Platte River Basin, with the most notable being a decrease in Agricultural land coverage and an increase in Vegetation and Grassland coverage. Land use changes varied across 13 focal cities across the entire basin. In particular, developed land in Grand Island, NE, nearly tripled from 2019 to 2023, making it a good possible candidate for restoration efforts. We overlaid a flood extent map with the LULC classifications in Grand Island to identify possible restoration sites under UWP. This data will inform Audubon Great Plains in identifying potential restoration sites in key cities.

Jennifer Mathis↗
NASA NTRSDate not supplied

Classical Flutter Analysis of X-57 Aircraft Mod II, III, and IV Configurations

To support airworthiness assessment of the X-57 electric propulsion demonstrator aircraft, the National Aeronautics and Space Administration (NASA) completed classical flutter analysis of the Mod II, Mod III, and Mod IV aircraft configurations. Aeroelastic analysis was primarily performed using the ZAERO analysis code developed by Zona Technology. Supplemental computational fluid dynamics (CFD) flutter analysis for the Mod III and Mod IV configurations was performed using NASA’s FUN3D software to verify the aeroelastic behavior at deployed flaps conditions. The NASTRAN finite element models (FEMs) used for aeroelastic analysis were developed by NASA. The final Mod II FEM utilized shell elements for the wing and fuselage, and beam elements for the tail and wing control surfaces. For Mod III and Mod IV aircraft models, shell element wing FEMs developed throughout the Mod III/IV wing design cycle were utilized. The fuselage and empennage FEM components were shared between the Mod II, III, and IV aircraft models. ZAERO analyses predicted flutter boundaries were >60% beyond the X-57 flight-test envelope never exceed airspeed (V NE ) for all configurations. Aeroelastic Reynolds-averaged Navier–Stokes (RANS) CFD simulations using FUN3D of the Mod III/IV configurations predicted flap mode instability did not occur until at least speeds of 60% higher than the Mod III/IV maximum flap deployment airspeed (V FE ).

Keerti K. Bhamidipati↗
NASA NTRSDate not supplied

Mission Concept, Science, and Technology of the PRIMA Astrophysics Probe

PRIMA addresses questions about the origins and growth of planets, supermassive black holes, stars, and dust. Much of the radiant energy from these formation processes is obscured and only emerges in the far infrared (IR) where PRIMA observes (24–261 um). PRIMA’s PI science program (25% of its 5-year mission) focuses on three questions and feeds a rich archival Guest Investigator program: How do exoplanets form and what are the origins of their atmospheres? How do galaxies’ black holes and stellar masses co-evolve over cosmic time? How do interstellar dust and metals build up in galaxies over time? PRIMA provides access to atomic (C, N, O, Ne) and molecular lines (HD, H2O, OH), redshifted PAH emission bands, and far-IR dust emission. PRIMA’s 1.8-m, 4.5-K telescope serves two instruments using sensitive KIDs: the Far-InfraRed Enhanced Survey Spectrometer (continuous, high-resolution spectral coverage with over an order of magnitude improvement in spectral line sensitivity and 3-5 orders of magnitude improvement in spectral survey speed) and the PRIMA Imager (hyperspectral imaging, broadband polarimetry). PRIMA opens new discovery space with 75% of the time for General Observers.

Jason Glenn↗
NASA NTRS2024

Optimization of Mission Enabling Broadband Lyman Ultraviolet Series to Infrared Aluminum Lithium Fluoride Reflectors

The Habitable Worlds Observatory (HWO) concept NASA flagship mission aims extend the ultraviolet (UV) observation range and sensitivity capabilities of the Hubble Space Telescope (HST) with respective goals of reaching photons down to 100 nm and containing an ultraviolet multi-object spectrograph with sensitivity improved 30-100 times. Adding the sensitivity capabilities near the Lyman series spectral range of ~100-121.6 nm reduces the reliance of redshift for key diagnostic ion lines such as O VI (103.2 nm), and heavily ionized gases of Ne VIII (77.5 nm) and MgX (62.5 nm). Clean and unoxidized aluminum (Al) reflectors provide optimal efficiency over a broadband down to the extreme ultraviolet (EUV) wavelength of ~83 nm. To prevent oxidation and maintain high spectral efficiency down to ~100 nm, the Al reflector is conventionally overcoated with a thin lithium fluoride (LiF) layer. We investigate the optimization of the deposition of the Al+LiF coating material composition to attain high spectral efficiency broadband reflectors down to 100 nm and enable the scientific goals of HWO. Lithium hexafluoroaluminate (Li3AlF6) is investigated as a different composition form of LiF to overcoat Al. The spectral efficiency and durability of the reflectors is evaluated. We will demonstrate the use of Li3AlF6 as an overcoat to protect aluminum yields ultra-high efficiency at the Hydrogen Lyman-alpha (HLyα, 121.6 nm) line with experimental reflectance values peaking up to 99%.

optical coatings↗
NASA NTRS2024

Optimization of Mission Enabling Broadband Lyman Ultraviolet Series to Infrared Aluminum Lithium Fluoride Reflectors

The Habitable Worlds Observatory (HWO) concept NASA flagship mission aims extend the ultraviolet (UV) observation range and sensitivity capabilities of the Hubble Space Telescope (HST) with respective goals of reaching photons down to 100 nm and containing an ultraviolet multi-object spectrograph with sensitivity improved 30-100 times. Adding the sensitivity capabilities near the Lyman series spectral range of ~100-121.6 nm reduces the reliance of redshift for key diagnostic ion lines such as O VI (103.2 nm), and heavily ionized gases of Ne VIII (77.5 nm) and MgX (62.5 nm). Clean and unoxidized aluminum (Al) reflectors provide optimal efficiency over a broadband down to the extreme ultraviolet (EUV) wavelength of ~83 nm. To prevent oxidation and maintain high spectral efficiency down to ~100 nm, the Al reflector is conventionally overcoated with a thin lithium fluoride (LiF) layer. We investigate the optimization of the deposition of the Al+LiF coating material composition to attain high spectral efficiency broadband reflectors down to 100 nm and enable the scientific goals of HWO. Lithium hexafluoroaluminate (Li3AlF6) is investigated as a different composition form of LiF to overcoat Al. The spectral efficiency and durability of the reflectors is evaluated. We will demonstrate the use of Li3AlF6 as an overcoat to protect aluminum yields ultra-high efficiency at the Hydrogen Lyman-alpha (HLyα, 121.6 nm) line with experimental reflectance values peaking up to 99%.

optical coatings↗
NASA NTRSDate not supplied

Investigating the Use of Machine Learning (ML) to Assess Tropospheric Doppler Radar Wind Profiler (TDRWP) Data Quality

Manual Quality Control (MQC) of Tropospheric Doppler Radar Wind Profiler (TDRWP) data is essential for defining an accurate climatology for downstream aerospace vehicle assessments. MQC traditionally takes around 30.5 hours per year of radar data. The Marshall Space Flight Center Natural Environments Branch (MSFC NE) used machine learning (ML) to test the feasibility of automating the MQC process, showing a potential to reduce labor by 300%. However, analysis of the model showed some false positives. We compared a neural network to the model to validate it and develop a process for assessing comparable solutions in the future.

Corey Walker↗
NASA NTRS2025

Nonthermal Velocities in a Solar Active Region Observed by SERTS

We present measurements of coronal nonthermal Doppler velocities in NOAA Active Region 7870 observed by the Solar EUV Research Telescope and Spectrograph during its 1995 sounding rocket flight (SERTS-95). The instrument included a multilayer-coated toroidal diffraction grating that enhanced its sensitivity in second order at wavelengths between about 171 and 225 Å. Analyses of spectra from this flight were previously published but did not address the issue of nonthermal velocities; we do so here for spectra averaged over the 123װ .8 segment of the slit for which the brightest portion of the region observed by SERTS was recorded. All emission lines are fit with Gaussian profiles. With post-flight laboratory spectra of He ii and Ne II-IIINe we derive a first-order instrumental width (full width at half-maximum intensity) of Finst,1 = 50.6 ± 3.1 mÅ and a second-order instrumental width of Finst,2 = 25.3 ±1.5 mÅ. For emission lines of Fe x−Fe xv, formed at 6.05 ≤ log T(K) ≤ 6.35, we find nonthermal velocities between 26.1 and 35.0 km s −1 , independent of temperature; this range corresponds to Vnonth = 30.6 ± 4.5 km s −1 . For the two unblended Fe xii lines at 192.394 and 193.509 Å closest to the maximum sensitivity of SERTS-95, we have Vnonth = 33.7 ± 1.3 km s −1 . When solar observations are used to derive or confirm instrumental widths for spectrometers in orbit, those observations should compensate for nonthermal velocities such as the ones reported here in order to extract instrumental widths that are free of nonthermal broadening.

Jeffrey W Brosius↗
NASA NTRS2020

Advances in Understanding High-Mass X-ray Binaries with INTEGRAL and Future Directions

High mass X-ray binaries are among the brightest X-ray sources in the Milky Way, as well as in nearby Galaxies. Thanks to their highly variable emissions and complex phenomenology, they have attracted the interest of the high energy astrophysical community since the dawn of X-ray Astronomy. In more recent years, they have challenged our comprehension of physical processes in many more energy bands, ranging from the infrared to very high energies. In this review, we provide a broad but concise summary of the physical processes dominating the emission from high mass X-ray binaries across virtually the whole electromagnetic spectrum. These comprise the interaction of stellar winds with the high gravitational and magnetic fields of compact objects, the behaviour of matter under extreme magnetic and gravity conditions, and the perturbation of the massive star evolutionary processes. We highlight the role of the INTEGRAL mission in the discovery of many of the most interesting objects in the high mass X-ray binary class and its contribution in reviving the interest for these sources over the past two decades. We show how the INTEGRAL discoveries have not only contributed to significantly increase the number of high mass X-ray binaries known, thus advancing our understanding of the population as a whole, but also have opened new windows of investigation that stimulated the multi-wavelength approach nowadays common in most astrophysical research fields. We conclude the review by providing an overview of future facilities being planned from the X-ray to the very high energy domain that will hopefully help us in finding an answer to the many questions left open after more than 18 years of INTEGRAL scientific observations.

Peter Kretschmar↗