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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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The Grass is Always Blacker: GaSb Grass as a Novel Antireflective Surface on IR Detectors
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OVIRS Visible to Near-IR Spectral Results at (101955) Bennu
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Investigation on the Origins of Comets as Revealed through IR High Resolution Spectroscopy: I. Molecular Abundances
We report and analyze molecular abundances updatedin twenty comets by employingmodern data reduction procedures and molecular models. Using boxplots and scatterplots, we examine how the different molecular species are distributed among the comet population, while by means of pie charts we investigate the relative proportions of these molecular species in each comet. We compare these results with the orbital parametersof the selected targets in order to identify trends related to the dynamical history of each comet. In this way, we identify at least three chemical classes based mainly on relative abundances of CO, CH3OH, CH4, C2H6, HCN and NH3. The combination of relative abundances and orbital parameters is then compared with chemical models of planetary system formation and may offer an alternative approach to investigate the origin and evolution of the material in cometary nuclei.Our study also confirms the need to add more objects to our sample in order to improve the statistics, especially for hyper-volatiles (i.e. CH4and CO) in Jupiter Family comets.
OVIRS Visible to Near-IR Spectral Results at (101955) Bennu
The OSIRIS-REx Visible and InfraRed Spectrometer (OVIRS) operates over a wavelength range of ~0.4 to 4.3 μm with a 4-mrad field of view.During the OSIRIS-REx mission, OVIRS collected more than 500,000 spectra of Bennu for spectral characterization of the surface. Constant phase angle observations were dedicated to global mapping at ~20 m resolution. Data with higher resolution (2–4 m) were obtained of the candidate sample sites. We analyzed low-phase-angle (12:30 pm local solar time) global data for surface color trends, surface temperatures, and the band depths of absorption features associated with hydrated minerals, carbon-bearing materials, iron oxides, and pyroxenes.
Fabrication of Phononic Filter Structures for Far-IR/sub-mm Detector Applications
A photon noise limited sub-mm/far-IR cold telescope in space will require detectors with noise equivalent power (NEP) less than 1x10-19W/Hz1/2for imaging applications and at least an order of magnitude lower for spectroscopic studies. The detector NEP can be reduced by lowering the operation temperature and improving the thermal isolation between the bolometer and a heat bath. We report on the fabrication of membrane isolated transition edge sensor bolometers incorporating compact (<50 μm) thermal isolation beams based on phononic filters. Phononic filters are created by etching quasi-periodic nanoscale structures into supporting thermo-mechanical beams. The cross-sectional dimensions of the etched features are less than the thermal wavelength at the operating temperature, enabling coherent phonon transport to take place in one dimension. The phonon stop-band can be tuned by adjusting the scale of the quasi-periodic structures. Cascading multiple filter stages can increase bandwidth and provide improved thermal isolation similar to the function of a multi-stage electrical filter. We describe the fabrication of AlMn based transition edge sensor bolometers on silicon and silicon nitride membranes isolated by one-and two-dimensional phononic filters. The phononic filters are patterned through electron beam lithography and isolated with deep reactive ion etching.
Lunar Ice Cube: ongoing development of first generation deep space cubesat mission with compact broadband IR spectrometer
Lunar Ice Cube (LIC) is one of 13 6U cubesats that will be deployed by EM1 in cislunar space. LIC along with Lunar Flashlight and LunaH-Map, all focused on the search for volatiles but with very different payloads, will be the first deep space cubesats designed to address goals for both demonstrating new technologies and collecting scientific data. Effectively, as their developments are occurring in parallel, they are acting as prototypes for future deep space cubesats missions. One useful outcome of this experiment is to evolve a working paradigm for the development and operation of compact, cost-capped, standardized (supporting subsystems) spacecraft to serve the needs of diverse user communities.
Delta Method Application for the Correlation of IR Detector Thermal Parasitic Loads with Statistically Accurate Results
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P-ACTIVE: Mid-wave IR Filter Beyond Terrestrial
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NASA Small Business Innovative Research (SBIR) Subtopic S2.04: X-Ray Mirror Systems Technology, Coating Technology: X-Ray, Ultraviolet (UV), Optical and Infrared (IR), and Free-Form Optics
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NASA 2022 SBIR Subtopic: S12.03 Advanced Optical Systems and Fabrication Testing/Control Technologies for EUV/Optical and IR Telescopes
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Polar Vortex Outbreak Air Transport: Observation using Satellite IR Sounder Derived Ozone Product and Comparison with Model
The Single Field of View (SFOV) Sounder Atmospheric Products (SiFSAP) derived from Cross-track Infrared Sounder (CrIS) on SNPP and JPSS have a spatial resolution ( ~14.5 km) better than most global weather and climate models. Most recent significant improvement in the quality of these products enables us to use these high-resolution observation-based sounding data for weather studies and model evaluation. The aim of this study is to explore the value to use these SFOV products for studying the dynamic transport associated with polar vortex outbreak. In a few cases studies, we used SiFSAP products, especially ozone, as well as the data of wind, geopotential height (GPH) and potential velocity (PV) from the fifth-generation ECMWF reanalysis (ERA5) data, to analyze the variation of total ozone, relative humidity and ozone in different layers, as well as their correlation with GPH and PV. Some comparison of the retrieved temperature and water vapor with ERA5 data, and ozone with the Ozone Mapping and Profiler Suite (OMPS) measurements have also been made. It is found (1) the transport of O3-riched polar air accompanying the polar vortex breakup to lower latitude and lower atmosphere, and (2) the transport path of O3 agreeing well with the path of polar cold air (illustrated using the retrieved RH, wind fields and GPH). These results demonstrate the 3-D structure of O3 distribution as derived from CrIS measurements provides some insights of the cold air transport, and can be used to track the dynamic transport of polar cold air following the outbreak of polar vortex. The observed enhancement of O3 following the polar vortex outbreak also suggests some possible linkage between the tropospheric cold air advected with stratospheric air source.