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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 397 records · Page 22
All sourcesNASA NTRSDOE OSTI
NASA NTRS2009

Quick-Connect Windowed Non-Stick Penetrator Tips for Rapid Sampling

Standard penetrator sampling systems were designed in order to allow for sampling via penetrators to produce a full set of sample acquisitions including volatile liquids, fine powders, and solid fragments. A gravity harpoon sampler has been designed with a removable tip and a quick coupling. The separation allows for sample handling and eliminates sample cross-contamination. Also, this design allows for multiple use of the penetrator body, which is the largest and heaviest part of the penetrator, while allowing for multiple changes of the light-mass, penetrator tip to avoid sample cross-contamination. The penetrator tip design has been improved by adding a spring trap to retain the sample, as well as a means for connecting to a quick coupling. Quick connect tips have been demonstrated in a sample handling carousel. The penetrator was released and rewound and the tips were released into a circular platter for rotation into instrument stations. The pyro-harpoon sampler was fabricated and tested with a NASA Standard Initiator (NSI) pyrotechnic charge. Initial tests collected cryogenic ice, but removal of the small pyro-harpoon from the ice was difficult. A brass metal sheath was then fitted over the harpoon tip, and removal from the ice was greatly alleviated by leaving the sheath in the ice. Quartz windows in the tips allow direct optical and spectral imaging and gas chromatography-mass spectrometer (GCMS) pyrolysis, and were found to survive impact. All systems were successfully tested by dropping into sand and into cryogenic ice.

Sherritt, Stewart↗
NASA NTRS2010

SUB 1-Millimeter Size Fresnel Micro Spectrometer

An ultra-small micro spectrometer with less than 1mm diameter was constructed using Fresnel diffraction. The fabricated spectrometer has a diameter of 750 nmicrometers and a focal length of 2.4 mm at 533nm wavelength. The micro spectrometer was built with a simple negative zone plate that has an opaque center with an ecliptic shadow to remove the zero-order direct beam to the aperture slit. Unlike conventional approaches, the detailed optical calculation indicates that the ideal spectral resolution and resolving power do not depend on the miniaturized size but only on the total number of rings. We calculated 2D and 3D photon distribution around the aperture slit and confirmed that improved micro-spectrometers below 1mm size can be built with Fresnel diffraction. The comparison between mathematical simulation and measured data demonstrates the theoretical resolution, measured performance, misalignment effect, and improvement for the sub-1mm Fresnel micro-spectrometer. We suggest the utilization of an array of micro spectrometers for tunable multi-spectral imaging in the ultra violet range.

Park, Yeonjoon↗
NASA NTRS2010

Geologic Mapping of the Lunar South Pole Quadrangle (LQ-30)

In this study we use recent image, spectral and topographic data to map the geology of the lunar South Pole quadrangle (LQ-30) at 1:2.5M scale [1-7]. The overall objective of this research is to constrain the geologic evolution of LQ-30 (60 -90 S, 0 - 180 ) with specific emphasis on evaluation of a) the regional effects of impact basin formation, and b) the spatial distribution of ejecta, in particular resulting from formation of the South Pole-Aitken (SPA) basin and other large basins. Key scientific objectives include: 1) Determining the geologic history of LQ-30 and examining the spatial and temporal variability of geologic processes within the map area. 2) Constraining the distribution of impact-generated materials, and determining the timing and effects of major basin-forming impacts on crustal structure and stratigraphy in the map area. And 3) assessing the distribution of potential resources (e.g., H, Fe, Th) and their relationships with surface materials.

Mest, S. C.↗
NASA NTRS2010

Constraining the Properties of the Eta Carinae System via 3-D SPH Models of Space-Based Observations: The Absolute Orientation of the Binary Orbit

The extremely massive (> 90 Solar Mass) and luminous (= 5 x 10(exp 6) Solar Luminosity) star Eta Carinae, with its spectacular bipolar "Homunculus" nebula, comprises one of the most remarkable and intensely observed stellar systems in the galaxy. However, many of its underlying physical parameters remain a mystery. Multiwavelength variations observed to occur every 5.54 years are interpreted as being due to the collision of a massive wind from the primary star with the fast, less dense wind of a hot companion star in a highly elliptical (e approx. 0.9) orbit. Using three-dimensional (3-D) Smoothed Particle Hydrodynamics (SPH) simulations of the binary wind-wind collision in Eta Car, together with radiative transfer codes, we compute synthetic spectral images of [Fe III] emission line structures and compare them to existing Hubble Space Telescope/Space Telescope Imaging Spectrograph (HST/STIS) observations. We are thus able, for the first time, to constrain the absolute orientation of the binary orbit on the sky. An orbit with an inclination of i approx. 40deg, an argument of periapsis omega approx. 255deg, and a projected orbital axis with a position angle of approx. 312deg east of north provides the best fit to the observations, implying that the orbital axis is closely aligned in 3-1) space with the Homunculus symmetry axis, and that the companion star orbits clockwise on the sky relative to the primary.

Madura, Thomas I.↗
NASA NTRS2006

Using Heaps in Recursive Hierarchical Segmentation of Data

A modification to increase processing speed has been made in the algorithm and implementing software reported in Modified Recursive Hierarchical Segmentation of Data (GSC-14681-1), NASA Tech Briefs, Vol. 30, No. 6 (June 2006), page 51. That software performs recursive hierarchical segmentation of data having spatial characteristics (e.g., spectral-image data). The segmentation process includes an iterative subprocess, in each iteration of which it is necessary to determine a best pair of regions to merge [merges being justified by one or more measure(s) similarity of pixels in the regions]. In the previously reported version of the algorithm and software, the choice of a best pair of regions to merge involved the use of a fully sorted list of regions. That version was computationally inefficient because a fully sorted list is not needed: what is needed is only the identity of the pair of regions characterized by the smallest measure of dissimilarity. The present modification replaces the use of a fully sorted list with the use of data heaps, which are computationally more efficient for performing the required comparisons among dissimilarity measures. The modification includes the incorporation of standard and modified functions for creating and updating data heaps

Tilton, James C.↗
NASA NTRS2002

Proceedings of the 11th JPL Airborne Earth Science Workshop

This publication contains the proceedings of the JPL Airborne Earth Science Workshop forum held to report science research and applications results with spectral images measured by the NASA Airborne Visible/Infrared Imaging Spectrometer (AVIRIS). These papers were presented at the Jet Propulsion Laboratory from March 5-8, 2001. Electronic versions of these papers may be found at the A VIRIS Web http://popo.jpl.nasa.gov/pub/docs/workshops/aviris.proceedings.html

Airborne Visible/Infrared Imaging Spectrometer (AV↗
NASA NTRS2011

Constraining the Properties of the Eta Carinae System via 3-D SPH Models of Space-Based Observations: The Absolute Orientation of the Binary Orbit

The extremely massive (> 90 Stellar Mass) and luminous (= 5 x 10(exp 6) Stellar Luminosity) star Eta Carinae, with its spectacular bipolar "Homunculus" nebula, comprises one of the most remarkable and intensely observed stellar systems in the Galaxy. However, many of its underlying physical parameters remain unknown. Multiwavelength variations observed to occur every 5.54 years are interpreted as being due to the collision of a massive wind from the primary star with the fast, less dense wind of a hot companion star in a highly elliptical (e approx. 0.9) orbit. Using three-dimensional (3-D) Smoothed Particle Hydrodynamics (SPH) simulations of the binary wind-wind collision, together with radiative transfer codes, we compute synthetic spectral images of [Fe III] emission line structures and compare them to existing Hubble Space Telescope/Space Telescope Imaging Spectrograph (HST/STIS) observations. We are thus able, for the first time, to tightly constrain the absolute orientation of the binary orbit on the sky. An orbit with an inclination of approx. 40deg, an argument of periapsis omega approx. 255deg, and a projected orbital axis with a position angle of approx. 312deg east of north provides the best fit to the observations, implying that the orbital axis is closely aligned in 3-D space with the Homunculus symmetry axis, and that the companion star orbits clockwise on the sky relative to the primary.

Madura, Thomas I.↗
NASA NTRS2012

Assessment of Global Cloud Datasets from Satellites: Project and Database Initiated by the GEWEX Radiation Panel

Clouds cover about 70% of the Earth's surface and play a dominant role in the energy and water cycle of our planet. Only satellite observations provide a continuous survey of the state of the atmosphere over the whole globe and across the wide range of spatial and temporal scales that comprise weather and climate variability. Satellite cloud data records now exceed more than 25 years in length. However, climatologies compiled from different satellite datasets can exhibit systematic biases. Questions therefore arise as to the accuracy and limitations of the various sensors. The Global Energy and Water cycle Experiment (GEWEX) Cloud Assessment, initiated in 2005 by the GEWEX Radiation Panel, provided the first coordinated intercomparison of publically available, standard global cloud products (gridded, monthly statistics) retrieved from measurements of multi-spectral imagers (some with multiangle view and polarization capabilities), IR sounders and lidar. Cloud properties under study include cloud amount, cloud height (in terms of pressure, temperature or altitude), cloud radiative properties (optical depth or emissivity), cloud thermodynamic phase and bulk microphysical properties (effective particle size and water path). Differences in average cloud properties, especially in the amount of high-level clouds, are mostly explained by the inherent instrument measurement capability for detecting and/or identifying optically thin cirrus, especially when overlying low-level clouds. The study of long-term variations with these datasets requires consideration of many factors. A monthly, gridded database, in common format, facilitates further assessments, climate studies and the evaluation of climate models.

Stubenrauch, C. J.↗
NASA NTRS2012

Extensive MRO CRISM Observations of 1.27 micron O2 Airglow in Mars Polar Night and Their Comparison to MRO MCS Temperature Profiles and LMD GCM Simulations

The Martian polar night distribution of 1.27 micron (0-0) band emission from O2 singlet delta [O2(1Delta(sub g))] is determined from an extensive set of Mars Reconnaissance Orbiter (MRO) Compact Reconnaissance Imaging Spectral Mapping (CRISM) limb scans observed over a wide range of Mars seasons, high latitudes, local times, and longitudes between 2009 and 2011. This polar nightglow reflects meridional transport and winter polar descent of atomic oxygen produced from CO2 photodissociation. A distinct peak in 1.27 micron nightglow appears prominently over 70-90NS latitudes at 40-60 km altitudes, as retrieved for over 100 vertical profiles of O2(1Delta(sub g)) 1.27 micron volume emission rates (VER). We also present the first detection of much (x80+/-20) weaker 1.58 micron (0-1) band emission from Mars O2(1Delta(sub g)). Co-located polar night CRISM O2(1Delta(sub g)) and Mars Climate Sounder (MCS) (McCleese et al., 2008) temperature profiles are compared to the same profiles as simulated by the Laboratoire de Météorologie Dynamique (LMD) general circulation/photochemical model (e.g., Lefèvre et al., 2004). Both standard and interactive aerosol LMD simulations (Madeleine et al., 2011a) underproduce CRISM O2(1Delta(sub g)) total emission rates by 40%, due to inadequate transport of atomic oxygen to the winter polar emission regions. Incorporation of interactive cloud radiative forcing on the global circulation leads to distinct but insufficient improvements in modeled polar O2(1Delta(sub g)) and temperatures. The observed and modeled anti-correlations between temperatures and 1.27 mm band VER reflect the temperature dependence of the rate coefficient for O2(1Delta(sub g)) formation, as provided in Roble (1995).

Atmosphere↗
NASA NTRS2014

Mechanisms and Observations of Coronal Dimming for the 2010 August 7 Event

Coronal dimming of extreme ultraviolet (EUV) emission has the potential to be a useful forecaster of coronal mass ejections (CMEs). As emitting material leaves the corona, a temporary void is left behind which can be observed in spectral images and irradiance measurements. The velocity and mass of the CMEs should impact the character of those observations. However, other physical processes can confuse the observations. We describe these processes and the expected observational signature, with special emphasis placed on the differences. We then apply this understanding to a coronal dimming event with an associated CME that occurred on 2010 August 7. Data from the Solar Dynamics Observatory's (SDO) Atmospheric Imaging Assembly (AIA) and EUV Variability Experiment (EVE) are used for observations of the dimming, while the Solar and Heliospheric Observatory's (SoHO) Large Angle and Spectrometric Coronagraph (LASCO) and the Solar Terrestrial Relations Observatory's (STEREO) COR1 and COR2 are used to obtain velocity and mass estimates for the associated CME. We develop a technique for mitigating temperature effects in coronal dimming from full-disk irradiance measurements taken by EVE. We find that for this event, nearly 100% of the dimming is due to mass loss in the corona.

Solar↗
NASA NTRS2014

Development and Preliminary Testing of a High Precision Long Stroke Slit Change Mechanism for the SPICE Instrument

In the frame of ESA's Solar Orbiter scientific mission, Almatech has been selected to design, develop and test the Slit Change Mechanism of the SPICE (SPectral Imaging of the Coronal Environment) instrument. In order to guaranty optical cleanliness level while fulfilling stringent positioning accuracies and repeatability requirements for slit positioning in the optical path of the instrument, a linear guiding system based on a double flexible blade arrangement has been selected. The four different slits to be used for the SPICE instrument resulted in a total stroke of 16.5 mm in this linear slit changer arrangement. The combination of long stroke and high precision positioning requirements has been identified as the main design challenge to be validated through breadboard models testing. This paper presents the development of SPICE's Slit Change Mechanism (SCM) and the two-step validation tests successfully performed on breadboard models of its flexible blade support system. The validation test results have demonstrated the full adequacy of the flexible blade guiding system implemented in SPICE's Slit Change Mechanism in a stand-alone configuration. Further breadboard test results, studying the influence of the compliant connection to the SCM linear actuator on an enhanced flexible guiding system design have shown significant enhancements in the positioning accuracy and repeatability of the selected flexible guiding system. Preliminary evaluation of the linear actuator design, including a detailed tolerance analyses, has shown the suitability of this satellite roller screw based mechanism for the actuation of the tested flexible guiding system and compliant connection. The presented development and preliminary testing of the high-precision long-stroke Slit Change Mechanism for the SPICE Instrument are considered fully successful such that future tests considering the full Slit Change Mechanism can be performed, with the gained confidence, directly on a Qualification Model. The selected linear Slit Change Mechanism design concept, consisting of a flexible guiding system driven by a hermetically sealed linear drive mechanism, is considered validated for the specific application of the SPICE instrument, with great potential for other special applications where contamination and high precision positioning are dominant design drivers.

Paciotti, Gabriel↗
NASA NTRS2015

Dramatic Change in Jupiter's Great Red Spot

Jupiter's Great Red Spot (GRS) is one of its most distinct and enduring features, having been continuously observed since the 1800's. It currently spans the smallest latitude and longitude size ever recorded. Here we show analyses of 2014 Hubble spectral imaging data to study the color, structure and internal dynamics of this long-live storm.

Red Spot↗
NASA NTRS2016

Pluto and Charon: Surface Colors and Compositions - A Hypothesis

The surface of Pluto displays an array of colors ranging from yellow to red to brown, while the surface of Charon is largely gray with a north polar zone of red color similar to regions on Pluto. Pluto's surface shows layers of intensely colored material in tilted and transported blocks, and fractured geo-graphical units. This arrangement suggests episodes of formation or deposition of that material interspersed with episodes of emplacement of ices having little or no color. The ices identified on the surfaces of these two bodies (N2, CH4, CO, C2H6, H2O on Pluto, and H2O and NH3 on Charon) are colorless, as are nearly all ices in a powdery state. The colors on Pluto probably arise from the in situ formation of a macro-molecular carbonaceous material generated by energetic processing of the ices on the surface. Laboratory experiments producing refractory tholins particularly relevant to Pluto explored the chemistry of both UV and low-energy electron bombardment of a mix of Pluto ices (N2:CH4:CO = 100:1:1). We can term this Pluto ice tholin PIT. Water ice in the crystalline state characterizes Charon's surface, and while most of Charon's surface is neutral in color, with geometric albedo approximately 0.38, the polar zone and a light cover of fainter but similar reddish color over some surface regions suggest a common origin with the colored material on Pluto. NH3 or NH3 x nH2O was identified from disk-integrated Earth-based spectra, and a few concentrated NH3 exposures have been found in the New Horizons spectral images.

Pluto↗
NASA NTRS2015

Toward an Integrated Solution to Mitigate the Impact of Volcanic Ash to Aviation

The science community is making a concerted effort to improve the reliability of dispersion models for the forecasting of volcanic ash plumes. Toward this end, it has been observed that the assimilation of diverse, accurate and frequent surface, airborne and satellite observations of the source and distal ash plumes may hold the key. Various international research organizations and operational agencies make these observations using a variety of active and passive remote sensing systems and use them to initialize atmospheric trajectory and dispersion models. These observation systems range from surface LIDAR and ceilometers, to airborne radiometers and nephelometers, to satellite radiometers, multi-spectral imagers, LIDAR and UV-photometers. None of these systems alone is a panacea, however, their synergistic application holds great promise toward solving this complex problem. Additionally, the aeronautical and science communities are working to better understand the quantitative thresholds and tolerances of aviation systems to volcanic ash to better inform scientists of the accuracy requirements for dispersion model forecasts. A number of the most recent and promising efforts in all of these area are discussed in this presentation.

Murray, John J.↗
NASA NTRS2016

Non-Equilibrium Plasma Applications for Water Purification Supporting Human Spaceflight and Terrestrial Point-of-Use

2016 NASA Glenn Technology Day Panel Presentation on May 24, 2016. The panel description is: Environmental Impact: NASA Glenn Water Capabilities Both global water scarcity and water treatment concerns are two of the most predominant environmental issues of our time. Glenn researchers share insights on a snow sensing technique, hyper spectral imaging of Lake Erie algal blooms, and a discussion on non-equilibrium plasma applications for water purification supporting human spaceflight and terrestrial point-of-use. The panel moderator will be Bryan Stubbs, Executive Director of the Cleveland Water Alliance.

Water resource/reuse↗
NASA NTRS2017

The Shadow Knows: Using Shadows to Investigate the Structure of the Pretransitional Disk of HD 100453

We present Gemini Planet Imager polarized intensity imagery of HD 100453 in Y, J, and K1 bands that reveals an inner gap (9-18 au), an outer disk (18-39 au) with two prominent spiral arms, and two azimuthally localized dark features that are also present in Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) total intensity images. Spectral energy distribution fitting further suggests that the radial gap extends to 1 au. The narrow, wedge-like shape of the dark features appears similar to predictions of shadows cast by an inner disk that is misaligned with respect to the outer disk. Using the Monte Carlo radiative transfer code HOCHUNCK3D, we construct a model of the disk that allows us to determine its physical properties in more detail. From the angular separation of the features, we measure the difference in inclination between the disks (45deg) and their major axes, PA = 140deg east of north for the outer disk, and 100deg for the inner disk. We find an outer-disk inclination of 25deg +/- 10deg from face-on, in broad agreement with the Wagner et al. measurement of 34deg. SPHERE data in J and H bands indicate a reddish disk, which indicates that HD 100453 is evolving into a young debris disk.

Spectro-Polarimetric High-contrast Exoplanet REsea↗
NASA NTRS2017

Finding the Needles in the Haystacks: High-Fidelity Models of the Modern and Archean Solar System for Simulating Exoplanet Observations

We present two state-of-the-art models of the solar system, one corresponding to the present day and one to the Archean Eon 3.5 billion years ago. Each model contains spatial and spectral information for the star, the planets, and the interplanetary dust, extending to 50 au from the Sun and covering the wavelength range 0.3-2.5 micron. In addition, we created a spectral image cube representative of the astronomical backgrounds that will be seen behind deep observations of extrasolar planetary systems, including galaxies and Milky Way stars. These models are intended as inputs to high-fidelity simulations of direct observations of exoplanetary systems using telescopes equipped with high-contrast capability. They will help improve the realism of observation and instrument parameters that are required inputs to statistical observatory yield calculations, as well as guide development of post-processing algorithms for telescopes capable of directly imaging Earth-like planets.

extrasolar planetary systems↗
NASA NTRS2017

Vertical Profiles of Mars 1.27 Micrometer O2 Dayglow from MRO CRISM Limb Spectra: Seasonal/global Behaviors, Comparisons to LMDGCM Simulations, and a Global Definition for Mars Water Vapor Profiles

Since July of 2009, The Compact Reconnaissance Imaging Spectral Mapper (CRISM) onboard the Mars Re- connaissance Orbiter (MRO) has periodically obtained pole-to-pole observations (i.e., full MRO orbits) of limb scanned visible/near IR spectra (lambda= 0.4 - 4.0 micrometers, delta lambda approx. 10 nm- Murchie et al., 2007). These CRISM limb observations support the first seasonally and spatially extensive set of Mars 1.27 micometers O2 (1 delta(sub g)) day-glow profile retrievals (approx. 1100) over greater than or equal to 8-80 km altitudes. Their comparison to Laboratoire de Meteorologie Dynamique (LMD) global climate model (GCM) simulated O2 (1 delta(sub g)) volume emission rate (VER) profiles, as a function of altitude, latitude, and season (solar longitude, L(sub s), supports several key conclusions regarding Mars atmospheric water vapor (which is derived from O2 (1 delta(sub g)) emission rates), Mars O3, and the collisional de-excitation of O2 (1 delta(sub g)) in the Mars CO2 atmosphere. Current (Navarro et al., 2014) LMDGCM simulations of Mars atmospheric water vapor fall 2-3 times below CRISM derived water vapor abundances at 20-40 km altitudes over low-to-mid latitudes in northern spring (L(sub s) = 30-60 deg), and northern mid-to-high latitudes over northern summer (L(sub s) = 60-140 deg). In contrast, LMDGCM simulated water vapor is 2-5 times greater than CRISM derived values at all latitudes and seasons above 40 km, within the aphelion cloud belt (ACB), and over high-southern to mid-southern latitudes in southern summer (L(sub s) = 190-340 deg) at 15-35 km altitudes. Overall, the solstitial summer-to-winter hemisphere gradients in water vapor are reversed between the LMDGCM modeled versus the CRISM derived water vapor abundances above 10-30 km altitudes. LMDGCM-CRISM differences in water vapor profiles correlate with LMDGCM-CRISM differences in cloud mixing profiles; and likely reflect limitations in simulating cloud microphysics and radiative forcing, both of which restrict meridional transport of water from summer- to-winter hemispheres on Mars (Clancy et al., 1996; Montmessin et al., 2004; Steele et al., 2014; Navarro et al., 2014) and depend on uncertain cloud microphysical properties (Navarro et al., 2014). The derived low-to-mid latitude changes in Mars water vapor vertical distributions should reduce current model- data disagreements in column O3 and H2O2 abundances over low-to-mid latitudes (e.g., within the ACB; Lefevre et al., 2008; Encrenaz et al., 2015; Clancy et al., 2016). Lastly, the global/seasonal average com- parison of CRISM and LMDGCM O2 (1 delta(sub g)) VER below 20 km altitudes indicates a factor of approx. 3 times lower value (0.25 x 10(exp -20) cu cm sec(exp -1)) for the CO2 collisional de-excitation rate coefficient of O2 (1 delta(sub g)) than derived recently by Guslyakova et al. (2016).

Clancy, R. Todd↗