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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Performance Results for the Prism Solar Installation at the New Mexico Regional Test Center: Field Data from February 15 - August 15 2016

A 9.6 kW test array of Prism bifacial modules and reference monofacial modules installed in February 2016 at the New Mexico Regional Test Center has produced six months of performance data. The data reveal that the Prism modules are out-performing the monofacial modules, with bifacial gains in energy over the six-month period ranging from 18% to 136%, depending on the orientation and ground albedo. These measured bifacial gains were found to be in good agreement with modeled bifacial gains using equations previously published by Prism. The most dramatic increase in performance was seen among the vertically tilted, west-facing modules, where the bifacial modules produced more than double the energy of monofacial modules and more energy than monofacial modules at any orientation. Because peak energy generation (mid-morning and mid-afternoon) for these bifacial modules may best match load on the electric grid, the west-facing orientation may be more economically desirable than traditional south-facing module orientations (which peak at solar noon).

14 SOLAR ENERGY↗
DOE OSTI2018

Projecting GeoVisipedia Annotations onto Satellite Imagey with the PRISM Algorithm

GeoVisipedia is a new and novel approach to sharing knowledge about complex geospatial configurations such as facilities. GeoVisipieda annotates objects in facilities with wiki pages. Annotations are projected to and from facility imagery using the PRISM algorithm. This report describes how the PRISM algorithm uses image metadata and a 3D facility model to perform annotation projection. The report concludes with an illustration of the efficacy of the PRISM algorithm in projecting an annotation onto a stack, and a demonstration of the effects of modeling error.

3D geospatial models↗
NASA NTRS1970

Less-expensive Rochon prisms

Inexpensive Rochon prisms can be produced by substituting easily polished glass for one-half of the calcite. Reciprocal polarizing properties of a conventional Rochon prism are retained, and angular separation between ordinary and extraordinary rays is the same as in all-calcite prism.

Ammann, E. O.↗
NASA NTRS1980

Rotatable prism for pan and tilt

Compact, inexpensive, motor-driven prisms change field of view of TV camera. Camera and prism rotate about lens axis to produce pan effect. Rotating prism around axis parallel to lens produces tilt. Size of drive unit and required clearance are little more than size of camera.

Ball, W. B.↗
NASA NTRS1994

PRISM project optical instrument

The scientific goal of the Passively-cooled Reconnaissance of the InterStellar Medium (PRISM) project is to map the emission of molecular hydrogen at 17.035 micrometers and 28.221 micrometers. Since the atmosphere is opaque at these infrared wavelengths, an orbiting telescope is being studied. The availability of infrared focal plane arrays enables infrared imaging spectroscopy at the molecular hydrogen wavelengths. The array proposed for PRISM is 128 pixels square, with a pixel size of 75 micrometers. In order to map the sky in a period of six months, and to resolve the nearer molecular clouds, each pixel must cover 0.5 arcminutes. This sets the focal length at 51.6 cm. In order for the pixel size to be half the diameter of the central diffraction peak at 28 micrometers would require a telescope aperture of 24 cm; an aperture of 60 cm has been selected for the PRISM study for greater light gathering power.

Taylor, Charles R.↗
NASA NTRS2011

Laser Oscillator Incorporating a Wedged Polarization Rotator and a Porro Prism as Cavity Mirror

A laser cavity was designed and implemented by using a wedged polarization rotator and a Porro prism in order to reduce the parts count, and to improve the laser reliability. In this invention, a z-cut quartz polarization rotator is used to compensate the wavelength retardance introduced by the Porro prism. The polarization rotator rotates the polarization of the linear polarized beam with a designed angle that is independent of the orientation of the rotator. This unique property was used to combine the retardance compensation and a Risley prism to a single optical component: a wedged polarization rotator. This greatly simplifies the laser alignment procedure and reduces the number of the laser optical components.

Li, Steven↗
NASA NTRSDate not supplied

WFIRST CGI: Prism and Polarizer Characterization Modes

As part of its technology demonstration, the WFIRST coronagraph instrument (CGI) will demonstrate point source spectroscopy and polarization measurements of disks. The specific implementation of spectroscopy is a zero-deviation Amici prism and slit to be placed on the planet after high contrast has been achieved by CGI. The polarization optics are a set of Wollaston prisms so that orthogonal polarization states can be measured simultaneously. The CGI spectral characterization mode, being designed and built and Goddard Space Flight Center (GSFC), has a spectral resolution of R50 and is designed to accommodate a 15% bandpass spanning 610-785nm. In order to recover Stokes information, there are two sets of Wollaston prisms clocked 45 degrees with respect to one another with each measurement taken in series. The Wollaston design and optical elements are a contribution by the Japanese Aerospace Exploration Agency, with final alignment and testing being done at GSFC. The spectroscopy mode is designed to target Methane absorption features around 730nm, keeping the spectral resolution as low as possible to improve the signal-to-noise ratio and hence reduce detection time. We highlight the requirements for these modes and address the challenge of on-orbit spectral calibration for a deployable slit in the presence of pointing drifts. Of unique interest is how the observatory error budget couples into good stellar spectrum calibration and subsequent speckle subtraction. We also provide further detail on the optomechanical design, its stability based on thermal and structural predictions, modeled performance, and operations concept. These performance metrics are simulated to demonstrate how a slit located at an arbitrary field point is homed onto the planet and converted to a calibrated spectrum.

Tyler D Groff↗
NASA NTRS2022

FY22 X-Hab: Colorado School of Mines: Planetary Resource & In-Situ Material Habitat Outfitting for Space Exploration (PRISM-HOUSE)

The Colorado School of Mines (CSM) was awarded a project under the Moon to Mars eXploration Systems and Habitation (M2M X-Hab) Academic Innovation Challenge on June 10, 2021 for the proposed Planetary Resource & In-Situ Material Habitat Outfitting for Space Exploration (PRISM-HOUSE) lunar habitat system. The project deliverables have been executed concurrently with coursework in the CSM Space Resources program, specifically for the Space Resources Project I & II classes. A team was established in the fall semester of 2021 and a Systems Engineering process was followed to brainstorm initial concepts, determine objectives, flow down top-level requirements, and identify areas for which the project could best further the understanding of the overall system through targeted detailed design and design evaluation testing. This report summarizes the overall project, as well as specific work completed in the spring semester of 2022. PRISM-HOUSE is a lunar habitat system that is deployed on the lunar surface robotically and supports safe, long-term human occupancy while maximizing the use of in-situ resources and minimizing the mass of supplies and equipment that must be delivered from Earth. In this report, the team provides an overview and description of the objectives, the system, and how the current design was selected from various alternatives, as well as the resulting products of systems engineering tasks such as product and specification trees and flow-down requirements. A review of current risks and planned mitigation are reviewed. Four key PRISM-HOUSE systems are explored: the inflatable Habitat, External Structures & Environmental Protection (ESEP), Human Interior Goods (HIG), and ECLSS & Remote Outfitting (E&RO); for each, the team provides a detailed system description and an overview of analyses performed supporting final design, followed by a review of each Design Evaluation Test (DET) performed and resulting conclusions. The report closes with a suggestion of next steps.

Peter Corwin↗
NASA NTRSDate not supplied

RST CGI: Final Verification and Calibration of Prism and Polarizer Flight Units

As part of its technology demonstration, the Nancy Grace Roman Space Telescope Coronagraph Instrument (CGI) will demonstrate point source spectroscopy and polarization measurements of disks. The spectroscopy mode is a zero-deviation Amici prism and slit which is deployed to the planet position after an imaging detection. The Wollaston prism polarization optics allow for imaging two orthogonal polarization states simultaneously. The CGI spectral characterization modes, designed and built at Goddard Space Flight Center (GSFC), have a spectral resolution of R50 in two 15% bandpass centered at 660nm and 730nm. There are duplicate Wollaston prism channels, clocked 45 degrees with respect to one another to completely characterize the instrument polarization effects and recover the Stokes parameters of the targeted disk. The Wollaston design and optical elements are a contribution by the Japanese Aerospace Exploration Agency, with final alignment and testing being done at GSFC. The spectroscopy mode is optimized to target Methane absorption features around 730nm, keeping the spectral resolution as low as possible to improve the signal-to-noise ratio and hence reduce detection time. We highlight the requirements for these modes, the ground-to-orbit calibration process, and the operations required to use a deployable slit on a CGI point source in the presence of pointing error. We also provide further detail on the optomechanical design, testing results from the final as-built flight units, verification process, and performance of the as-built flight assemblies.

high contrast imaging↗
DOE OSTI2015

Investigation of optical properties of multilayer dielectric structures using prism-coupling technique

A method based on resonant excitation of waveguide modes with a prism coupler is proposed for measuring the thickness and refractive index of thin-film layers in multilayer dielectric structures. The peculiarities of reflection of TE- and TM-polarised light beams from a structure comprising eleven alternating layers of zinc sulfide (ZnS) and magnesium barium fluoride (MgBaF{sub 4}), whose thicknesses are much less than the wavelength of light, are investigated. Using the mathematical model developed, we have calculated the coefficients of reflection of collimated TE and TM light beams from a multilayer structure and determined the optical constants and thicknesses of the structure layers. The refractive indices of the layers, obtained for TE and TM polarisation of incident light, are in good agreement. The thicknesses of ZnS and MgBaF{sub 4} layers, found for different polarisations, coincide with an accuracy of ±1%. Thus, we have demonstrated for the first time that the prism-coupling technique allows one to determine the optical properties of thin-film structures when the number of layers in the structure exceeds ten layers. (integrated optics)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2017

Optimisation of the prism coupling of optical whispering-gallery-mode microcavities

The methods for increasing the coupling efficiency of a prism with spheroidal microcavities, aimed at exciting whispering-gallery modes, have been analytically investigated. Optimal angles of incidence and incident beam parameters are obtained for a spheroidal cavity. The cavity eigenfrequency shift caused by the presence of a prism and the introduced loss by it is calculated. (resonators)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2019

Basing of Surfaces of Revolution on Immobile Prisms

The basing of parts with surfaces of revolution in a self-centering vise and a motionless prism is considered, for the example of a disk and a shaft. In the case of an immobile prism, violation of basing principles produces indeterminacy because of redundant reference points. That gives rise to a basing error.

42 ENGINEERING↗
NASA NTRS1994

(abstract) A Comparison Between Measurements of the F-layer Critical Frequency and Values Derived from the PRISM Adjustment Algorithm Applied to Total Electron Content Data in the Equatorial Region

The Parametrized Real-Time Ionosphere Specification Model (PRISM) is a global ionospheric specification model that can incorporate real-time data to compute accurate electron density profiles. Time series of computed and measured data are compared in this paper. This comparison can be used to suggest methods of optimizing the PRISM adjustment algorithm for TEC data obtained at low altitudes.

total electron content TEC PRISM electron content ↗
DOE OSTI2018

Hexagonal Nanopyramidal Prisms of Nearly Intrinsic InN on Patterned GaN Nanowire Arrays

By using multiple growth steps that separate the nucleation and growth processes, we show that nearly intrinsic InN single nanocrystals of high optical quality can be formed on patterned GaN nanowire arrays by molecular beam epitaxy. The InN nanostructures form into well-defined hexagonal prisms with pyramidal tops. Micro-photoluminescence (μ-PL) is carried out at low temperature (LT: 28.2 K) and room temperature (RT: 285 K) to gauge the relative material quality of the InN nanostructures. Nanopyramidal prisms grown using a three-step growth method are found to show superior quantum efficiency. In conclusion, excitation and temperature dependent μ-PL demonstrates the very high quality and nearly intrinsic nature of the ordered InN nanostructure arrays.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Si-centered capped trigonal prism ordering in liquid Pd 82 Si 18 alloy study by first-principles calculations

First-principles molecular dynamic (MD) simulation and X-ray diffraction were employed to study the local structures of Pd–Si liquid at the eutectic composition (Pd 82 Si 18 ). Here, a strong repulsion is found between Si atoms, and Si atoms prefer to be evenly distributed in the liquid. The dominate local structures around Si atoms are found to be with of a trigonal prism capped by three half-octahedra and an archimedean anti-prism. The populations of these clusters increase significantly upon cooling, and may play an important role in the formation of Pd 82 Si 18 alloy glass.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Terahertz VRT spectroscopy of the water hexamer-d 12 prism: Dramatic enhancement of bifurcation tunneling upon librational excitation

Using diode laser vibration-rotation-tunneling spectroscopy near 15 Thz (500 cm -1 ), we have measured and assigned 142 transitions to three a-type librational subbands of the water hexamer-d12 prism. These subbands reveal dramatically enhanced (ca. 1000×) tunneling splittings relative to the ground state. This enhancement is in agreement with that observed for the water dimer, trimer, and pentamer in this same frequency region. The water prism tunneling motion has been predicted to potentially describe the motions of water in interfacial and confined environments; hence, the results presented here indicate that excitation of librational vibrations has a significant impact on the hydrogen bond dynamics in these macroscopic environments.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Hunting for light dark matter with DUNE PRISM

We present the prospects for exploring low-scale dark sectors with the future DUNE experiment and the impact of the movable off-axis near detector concept, DUNE-PRISM, and a higher energy beam configuration. We focus on a simple scenario which extends the Standard Model by a “dark” U(1), comprising scalar or fermion dark matter and a dark photon kinetically mixed with the photon. We consider nucleus and electron scattering signatures of dark matter produced in the beam via neutral pseudoscalar meson decays. Our results show that, by analysing the energy spectra of single electron events in multiple off-axis angle, DUNE-PRISM can substantially increase the experimental sensitivity to these models, reaching theoretical targets for thermal relic dark matter for a wide range of dark photon and dark matter masses.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗