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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 505 records · Page 28
All sourcesNASA NTRSDOE OSTI
NASA NTRS1998

The Hadean, Through a Glass Telescopically: Observations of Young Solar Analogs

Investigations into the Earth's surface environment during the Hadean eon (prior to 3.8 Ga) are hampered by the paucity of the geological and geochemical record and the relative inaccessibility of better-preserved surfaces with possibly similar early histories (i.e., Mars). One approach is to observe nearby, young solar-mass stars as analogs to the Hadean Sun and its environment. A catalog of 38 G and early K stars within 25 pc was constructed based on main-sequence status, bolometric luminosity, lack of known stellar companions within 800 AU, and coronal X-ray luminosities commensurate with the higher activity of solar-mass stars <0.8 b.y. old. Spectroscopic data support the assignment of ages of 0.2 - 0.8 Ga for most of these stars. Observations of these objects will provide insight into external forces that influenced Hadean atmosphere, ocean, and surface evolution (and potential ecosystems), including solar luminosity evolution, the flux and spectrum of solar ultraviolet radiation, the intensity of the solar wind, and the intensity and duration of a late period of heavy bombardment. The standard model of solar evolution predicts a luminosity of 0.75 solar luminosity at the end of the Hadean, implying a terrestrial surface temperature inconsistent with the presence of liquid water and motivating atmospheric greenhouse models. An alternative model fo solar evolution that invokes mass loss, constructed to explain solar Li depletion, attenuates or reverses this luminosity evolution of the atmospheres of Earth and the other terrestrial planets. This model can be tested by Li abundance measurements. The continuum emission from stellar wind plasma during significant mass loss may be detectable at millimeter and radio wavelengths. The Earth (and Moon) experienced a period of intense bombardment prior to 3.8 Ga, long after accretion was completed in the inner solar system and possibly associated with the clearing of residual planetesimals in the outer solar system. Such a bombardment may have contributed volatiles and organics to the surface, but also have limited the appearacne of a biosphere. While planetary systems around solar systems cannot be detected directly with present technology, the thermal emission from the interplanetary dust generated during a similar heavy bombardment period can be. Midinfrared observations of a large uniform sample of solar analogs are used to constrain the frequency and duration of such events.

Gaidos, E. J.↗
NASA NTRS2001

The Fabrication of an Evanescent Field Sensor

We present current results concerning novel sensor-based applications for tilted angle fiber Bragg gratings summarized in a recently filed patent. In addition, concepts involving the coupling of light out of the core region of an optical fiber using ablated corrugations to induce interactions with the surrounding media will also be discussed. The interactions between the media and the coupled light formulate the sensing mechanism for both of these devices. The research illustrated here is an extension of previous work that investigated the affects of intense UV radiation fields on both SiO2 and Ge-doped SiO2-based structures (specifically optical fibers and preforms). Finally, these sensors were devised in order to satisfy an experimental task set forth by NASA Glenn involving the production of a prototype evanescent field sensor capable of real-time, dynamic index of refraction measurements as well as early (ultra-high sensitivity) detection of icing on airplane wings.

Lyons, Donald R.↗
NASA NTRS2001

Remote Sensing of the Urban Heat Island Effect: Assessment of Risks to Human Health and Development of Mitigation Strategies for Sustainable Cities

The growth of cities, both in population and in areal extent, appears as an inexorable process. Urbanization continues at a rapid rate, and it is estimated that by the year 2025, 80% of the world's population will live in cities. One of the more egregious side effects of urbanization is the deterioration in air quality as a result of increased vehicular traffic, industrialization and related activities. In the United States alone, under the more stringent air quality guidelines established by the U.S. Environmental Protection Agency (EPA) in 1997, nearly 300 counties in 34 states will not meet the new air quality standards for ground level ozone. The mitigation of one the physical/environmental characteristics of urbanization known as the urban heat island (UHI) effect, is now being looked at more closely as a possible way to bring down ground level ozone levels in cities and assist states in improving air quality. The UHI results from the replacement of "natural" land covers (e.g., trees, grass) with urban land surface types, such as pavement and buildings. Heat stored in these surfaces is released into the air and results in a "dome" of elevated air temperatures that presides over cities. The effect of this dome of elevated air temperatures is known as the UHI, which is most prevalent about 2-3 hours after sunset on days with intense solar radiation and calm winds. Given the local and regional impacts of the UHI, there are significant potential affects on human health, particularly as related to heat stress and ozone on body temperature regulation and on the cardiovascular and respiratory systems. In this study we are using airborne and satellite remote sensing data to analyze how differences in the urban landscape influence or drive the development of the UHI over four U.S. cities. Additionally, we are assessing what the potential impact is on risks to human health, and developing mitigation strategies to make urban areas more environmentally sustainable.

Quattrochi, Dale A.↗
NASA NTRS2002

High Spatial Resolution Thermal Remote Sensing of the Urban Heat Island Effect: Assessment of Risks to Human Health and Development of Mitigation Strategies for Sustainable Cities

The growth of cities, both in population and in areal extent, appears as an inexorable process. Urbanization continues at a rapid rate, and it is estimated that by the year 2025, 80% of the world's population will live in cities. One of the more egregious side effects of urbanization is the deterioration in air quality as a result of increased vehicular traffic, industrialization and related activities. In the United States alone, under the more stringent air quality guidelines established by the U.S. Environmental Protection Agency (EPA) in 1997, nearly 300 counties in 34 states will not meet the new air quality standards for ground level ozone. The mitigation of one the physical/environmental characteristics of urbanization known as the urban heat island (UHI) effect, is now being looked at more closely as a possible way to bring down ground level ozone levels in cities and assist states in improving air quality. The UHI results from the replacement of "natural" land covers (e.g., trees, grass) with urban land surface types, such as pavement and buildings. Heat stored in these surfaces is released into the air and results in a "dome" of elevated air temperatures that presides over cities. The effect of this dome of elevated air temperatures is known as the UHI, which is most prevalent about 2-3 hours after sunset on days with intense solar radiation and calm winds. Given the local and regional impacts of the UHI, there are significant potential affects on human health, particularly as related to heat stress and ozone on body temperature regulation and on the cardiovascular and respiratory systems. In this study we are using airborne and satellite remote sensing data to analyze how differences in the urban landscape influence or drive the development of the UHI over four U.S. cities. Additionally, we are assessing what the potential impact is on risks to human health, and developing mitigation strategies to make urban areas more environmentally sustainable.

Quattrochi, Dale A.↗
NASA NTRS2000

High Resolution X-Ray Spectroscopy of zeta Puppis with the XMM-Newton Reflection Grating Spectrometer

We present the first high resolution X-ray spectrum of the bright O4Ief supergiant star Puppis, obtained with the Reflection Grating Spectrometer on- board XMM-Newton. The spectrum exhibits bright emission lines of hydrogen-like and helium-like ions of nitrogen, oxygen, neon, magnesium, and silicon, as well as neon-like ions of iron. The lines are all significantly resolved, with characteristic velocity widths of order 1000 - 1500 km/ s. The nitrogen lines are especially strong, and indicate that the shocked gas in the wind is mixed with CNO-burned material, as has been previously inferred for the atmosphere of this star from ultraviolet spectra. We find that the forbidden to intercombination line ratios within the helium-like triplets are anomalously low for N VI, O VII, and Ne IX. While this is sometimes indicative of high electron density, we show that in this case, it is instead caused by the intense ultraviolet radiation field of the star. We use this interpretation to derive constraints on the location of the X-ray emitting shocks within the wind that agree remarkably well with current theoretical models for this system.

Kahn, S. M.↗
NASA NTRS2004

Simulation experiments of the effect of space environment on bacteriophage and DNA thin films

The main goal of PUR experiment (phage and uracil response) is to examine and quantify the effect of specific space conditions on nucleic acid models. To achieve this an improved method was elaborated for the preparation of DNA and bacteriophage thin films. The homogeneity of the films was controlled by UV spectroscopy and microscopy. To provide experimental evidence for the hypothesis that interplanetary transfer of the genetic material is possible, phage T7 and isolated T7 DNA thin films have been exposed to selected space conditions: intense UVC radiation (lambda=254 nm) and high vacuum (10(-4) Pa). The effects of DNA hydration, conformation and packing on UV radiation damage were examined. Characteristic changes in the absorption spectrum, in the electrophoretic pattern of DNA and the decrease of the amount of PCR products have been detected indicating the photodamage of isolated and intraphage DNA. c2004 COSPAR. Published by Elsevier Ltd. All rights reserved.

Bacteriophage T7/genetics/radiation effects↗
NASA NTRS1979

Window Insulation

A highly reflective insulating material developed to protect NASA spacecraft from intense solar radiation is now being used in a commercially-available window-insulating product which offers significant energy savings. Called Nunsun, it is a thin metallized film adhesively bonded to windows of homes, office buildings, schools, industrial plants and other facilities; the film reflects the sun's heat and glare outward, thereby cutting down on energy costs for cooling. Trained dealer personnel can affix the film to windows of any size in minutes (right), converting ordinary glass to heat-reflective mirror glass at a fraction of the cost. Manufactured by National Metallizing, a division of Standard Packaging Corporation, Cranbury, New Jersey, Nunsun is also available in windowshade form.

Source record↗
NASA NTRS1989

CCD imaging sensors

A method for promoting quantum efficiency (QE) of a CCD imaging sensor for UV, far UV and low energy x-ray wavelengths by overthinning the back side beyond the interface between the substrate and the photosensitive semiconductor material, and flooding the back side with UV prior to using the sensor for imaging. This UV flooding promotes an accumulation layer of positive states in the oxide film over the thinned sensor to greatly increase QE for either frontside or backside illumination. A permanent or semipermanent image (analog information) may be stored in a frontside SiO.sub.2 layer over the photosensitive semiconductor material using implanted ions for a permanent storage and intense photon radiation for a semipermanent storage. To read out this stored information, the gate potential of the CCD is biased more negative than that used for normal imaging, and excess charge current thus produced through the oxide is integrated in the pixel wells for subsequent readout by charge transfer from well to well in the usual manner.

Janesick, James R.↗
NASA NTRS2008

Development of the Lunar Environments Test System (LETS)

The lunar surface is an inhospitable environment to work in to say the least. The environment on the lunar surface is defined by intense ultraviolet radiation, solar wind radiation (primarily electrons and protons), electrically charged dust layers, and temperatures as low as -200 C. As NASA makes plans to send manned missions to the moon's surface, significant preparation must be undertaken to ensure that the materials and mechanical components used on those missions can survive in the harsh environment. The work presented will detail the development of the Lunar Environment Test System (LETS) at the Marshall Space Flight Center that will allow scientists and engineers the ability to test new materials, mechanical components, and proposed mission hardware in a representative lunar surface environment. The LETS encompasses all the environments of the lunar surface including vacuum, thermal extremes, vacuum ultraviolet radiation, and protons and electrons from the solar wind.

Vaughn, Jason A.↗
NASA NTRS2012

The Carbonates in ALH 84001 Record the Evolution of the Martian Atmosphere Through Multiple Formation Events

Current Martian conditions restrict the presence of liquid water due to low temperatures (approx 210K), a thin atmosphere (approx 7mb), and intense UV radiation. However, past conditions on Mars may have been different with the possibility that the ancient Martian climate was warm and wet with a dense CO2 atmosphere. The cycling of carbon on Mars through atmospheric CO2 and carbonate minerals is critical for deciphering its climate history. In particular stable isotopes contained in carbonates can provide information of their origin and formation environment as well as possibly hinting at the composition of global reservoirs such as atmospheric CO2. Martian meteorite ALH 84001 contains widely studied carbonate rosettes that have been dated to approx. 3.9 Ga and have been used to interpret climatic conditions present at that time. However, there is mount-ing evidence for multiple episodes of carbonate formation in ALH 84001 with potentially distinct isotopic compositions. This study seeks to tease out these different carbonate assemblages using stepped phosphoric acid dissolution and analysis of carbon and triple oxygen stable isotopes. In addition, we report SIMS analyses of the delta O-18 several petrographically unusual carbonate phases in the meteorite.

Shaheen, R.↗
NASA NTRS2019

Analyses and Methods of Solid Rocket Motor Material Irradiation at Marshall Space Flight Center

The search for life on other worlds is among humanity’s greatest endeavors. Europa represents the most probable location to discover extraterrestrial life in our solar system, owing to its surface composition of ice covering a liquid water ocean, warmed by the tidal forces of its orbit around Jupiter. Unfortunately, the Jovian system hosts the most intense planetary radiation environment in the solar system due to the charged particles, namely electrons and protons, trapped by Jupiter’s immense magnetic field. Any mission that attempts to approach or land on Europa must survive this radiation environment [Hand et al, 2017]. Radiation effects were identified as a priority risk to the successful development of a de-orbit stage and solid rocket motor (SRM) early in the Europa Lander De-orbit Stage project concept. The effects of primary concern tend to occur very near the outer surface of the SRM. The charged particles deposit their energy quickly and are mostly stopped in the outer metallic case, but a significant portion of radiation penetrates through the bondline and outer propellant regions. High doses of ionizing radiation are known to cause significant changes to mechanical properties of many materials, especially polymers. For polymers such as the rubber-like materials (elastomers) in a solid rocket motor, the primary damage mechanism is known as cross-linking, in which ionization causes the restructuring of the matrix of long polymer chains. Ionization energy breaks the long polymer chains and allows formation of new cross-linked bonding sites. This hardens and often strengthens the polymer, but at the cost of decreased flexibility (or modulus). Propellant, insulation, liner, and pyrotechnic materials were identified as higher risk items, and so were irradiated at Marshall Space Flight Center (MSFC) for investigation of changes in mechanical and ballistic properties. This process required significant levels of analysis to evaluate how the radiation environment evolves within the spacecraft during the mission, and also to evaluate how dose is delivered into test articles within the irradiating facilities.

Caffrey, Jarvis↗
NASA NTRS2019

Analyses and Methods of Solid Rocket Motor Material Irradiation at Marshall Space Flight Center

The search for life on other worlds is among humanity’s greatest endeavors. Europa represents the most probable location to discover extraterrestrial life in our solar system, owing to its surface composition of ice covering a liquid water ocean, warmed by the tidal forces of its orbit around Jupiter. Unfortunately, the Jovian system hosts the most intense planetary radiation environment in the solar system due to the charged particles, namely electrons and protons, trapped by Jupiter’s immense magnetic field. Any mission that attempts to approach or land on Europa must survive this radiation environment [Hand et al, 2017]. Radiation effects were identified as a priority risk to the successful development of a de-orbit stage and solid rocket motor (SRM) early in the Europa Lander De-orbit Stage project concept. The effects of primary concern tend to occur very near the outer surface of the SRM. The charged particles deposit their energy quickly and are mostly stopped in the outer metallic case, but a significant portion of radiation penetrates through the bondline and outer propellant regions. High doses of ionizing radiation are known to cause significant changes to mechanical properties of many materials, especially polymers. For polymers such as the rubber-like materials (elastomers) in a solid rocket motor, the primary damage mechanism is known as cross-linking, in which ionization causes the restructuring of the matrix of long polymer chains. Ionization energy breaks the long polymer chains and allows formation of new cross-linked bonding sites. This hardens and often strengthens the polymer, but at the cost of decreased flexibility (or modulus). Propellant, insulation, liner, and pyrotechnic materials were identified as higher risk items, and so were irradiated at Marshall Space Flight Center (MSFC) for investigation of changes in mechanical and ballistic properties. This process required significant levels of analysis to evaluate how the radiation environment evolves within the spacecraft during the mission, and also to evaluate how dose is delivered into test articles within the irradiating facilities.

Caffrey, Jarvis↗
NASA NTRS2017

The Intelligent Landing System for Safe and Precise Landing on Europa

Europa, the smallest of Jupiter’s Galilean moons, is thought to harbor a vast liquid water ocean beneath its icy crust, making it one of the most scientifically intriguing targets for a robotic surface sampling mission in our Solar System. However, autonomously landing a spacecraft safely and precisely on Europa poses unique challenges, such as very little existing high-resolution reconnaissance imagery, a surface expected to be very rough and hazardous over a wide range of scales, an extremely intense ionizing radiation environment, and very limited lander resources for mass and volume. To address these challenges, we propose a novel Intelligent Landing System (ILS) combining four Guidance, Navigation & Control (GN&C) sensing functions – velocimetry, altimetry, map-relative localization, and hazard detection – that would together enable safe and precise landing on Europa’s surface. The ILS is a smart sensor system, combining an inertial measurement unit (IMU), a monocular, passive-optical camera, and a light detection and ranging (Li-DAR) sensor with dedicated computing resources as well as an onboard 3D terrain map. The ILS leverages more than a decade of technology development from programs such as the Lander Vision System, currently baselined on the Mars 2020 mission. This paper provides a detailed description of the proposed ILS architecture and concept of operations, as well as select preliminary simulation results to assess performance and robustness.

Trawny, Nikolas↗
NASA NTRS2024

JWST Mid-Infrared Spectroscopy Resolves Gas, Dust, and Ice in Young Stellar Objects in the Large Magellanic Cloud

In this work, we present spectra of 11 young stellar objects (YSOs) taken with the Mid-Infrared Instrument (MIRI) / Medium Resolution Spectroscopy (MRS) instrument onboard the James Webb Space Telescope (JWST). The YSOs are located in the N79 region of the Large Magellanic Cloud (LMC), an active star forming region with hundreds of Spitzer - and Herschel-identified YSOs and host to super star cluster (SSC) candidate H72.97-69.39. The three giant molecular clouds (GMCs) in N79 (East, West, and South) have varying star formation rates and stellar populations. MRS follow-up observations of four Spitzer -identified YSOs in N79 East, West, and South reveal that what seemed to be a single, massive YSO is actually a cluster of YSOs. We discuss the emission and absorption lines of six YSOs which have complete or almost-complete spectral coverage from 4.9 – 27.9 µm. YSO Y3, located in N79 East, is the youngest source in this study and likely to be less than 10,000 years old inferred from the prominent CH 4 , NH 3 , CH 3 OH, CH 3 OCHO, and CO 2 ice absorption features. The most luminous source is the central ionizing YSO of SSC H72.97-69.39, Y4, which has dozens of fine-structure and H 2 emission lines. Unlike the other YSOs in this work, Y4 has no polyaromatic hydrocarbon (PAH) emission lines due to the intense ionizing radiation destroying these large carbon chain molecules. The mass accretion rate based on H I (7-6) line luminosity of YSOs Y1, Y2, Y4, and Y9 range between 1.22 × 10 −4 – 1.89 × 10 −2 M ⊙ yr −1 For the first time in the mid-infrared, we are able to resolve individual high-mass protostars forming in small clusters in an extra-galactic environment like the LMC.

Omnarayni Nayak↗
NASA NTRS2007

Modeling of Radiative Transfer in Protostellar Disks

This program implements a spectral line, radiative transfer tool for interpreting Spitzer Space Telescope observations by matching them with models of protostellar disks for improved understanding of planet and star formation. The Spitzer Space Telescope detects gas phase molecules in the infrared spectra of protostellar disks, with spectral lines carrying information on the chemical composition of the material from which planets form. Input to the software includes chemical models developed at JPL. The products are synthetic images and spectra for comparison with Spitzer measurements. Radiative transfer in a protostellar disk is primarily affected by absorption and emission processes in the dust and in molecular gases such as H2, CO, and HCO. The magnitude of the optical absorption and emission is determined by the population of the electronic, vibrational, and rotational energy levels. The population of the molecular level is in turn determined by the intensity of the radiation field. Therefore, the intensity of the radiation field and the population of the molecular levels are inter-dependent quantities. To meet the computational challenges of solving for the coupled radiation field and electronic level populations in disks having wide ranges of optical depths and spatial scales, the tool runs in parallel on the JPL Dell Cluster supercomputer with C++ and Fortran compiler with a Message Passing Interface. Because this software has been developed on a distributed computing platform, the modeling of systems previously beyond the reach of available computational resources is possible.

VonAllmen, Paul↗