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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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NASA NTRSDate not supplied

An Overview of MaGIXS-2, The Second Flight of the Marshall Grazing Incidence X-ray Spectrometer

MaGIXS is a slitless soft X-ray (SXR) imaging spectrometer designed to observe solar active regions. - The instrument produces spatially resolved SXR spectra, known as “overlappograms.” (Athiray et al. 2019 & Champey et al., 2022) The first sounding rocket flight of the Marshall Grazing Incidence X-ray Spectrometer occurred on July 30, 2021 from the White Sands Missile Range, New Mexico. - Spectrally pure images of X-ray bright points were obtained through the inversion of overlappograms, e.g. Fig. 3 (Savage et al., 2022). MaGIXS 2 is a simplified version of the original design, less the spectrometer mirror pair. - Eliminating the spectrometer mirror pair improves spatial resolution, increases effective area and the field of view (Table 1). No field stop in this design, data will be an overlappogram with the same spatial and spectral plate scale.

x-ray spectrometer, x-ray optics, solar corona, so↗
DOE OSTI2020

First Images of the Protoplanetary Disk around PDS 201

Scattered light imaging has revealed nearly a dozen circumstellar disks around young Herbig Ae/Be stars—enabling studies of structures in the upper disk layers as potential signs of ongoing planet formation. We present the first images of the disk around the variable Herbig Ae star PDS 201 (V* V351 Ori) and an analysis of the images and spectral energy distribution through 3D Monte Carlo radiative transfer simulations and forward modeling. The disk is detected in three data sets with the Large Binocular Telescope Interferometer/Large Binocular Telescope mid-infrared camera at the Large Binocular Telescope, including direct observations in the Ks and L′ filters, and an L′ observation with the 360° vector apodizing phase plate coronagraph. The scattered light disk extends to a very large radius of ∼250 au, which places it among the largest of such disks. Exterior to the disk, we establish detection limits on substellar companions down to ∼5 M {sub Jup} at ≳1.″5 (≳500 au), assuming the Baraffe et al. models. The images show a radial gap extending to ∼0.″4 (∼140 au at a distance of 340 pc) that is also evident in the spectral energy distribution. The large gap is a possible signpost of multiple high-mass giant planets at orbital distances (∼60–100 au) that are unusually massive and widely separated compared to those of planet populations previously inferred from protoplanetary disk substructures.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1988

Radiometric performance of AVIRIS: Assessment for an arid region geologic target

Data from several AVIRIS flight lines were examined to assess instrument stability and response. Both scene and in-flight calibration data were analyzed statistically. The data clearly indicates that, although the instrument output was noisy and unstable at the time of the data acquisition, valuable spectral signatures can still be extracted and analyzed. Some first order calibration corrections can be performed by forcing internal consistency within the data. AVIRIS data are delivered in band-interleaved-by-line format, but high efficiency routines were developed which access the data as either image or spectral planes and enable effective statistical and visual examination of both AVIRIS scenes and ancillary files. Two methods were used to extract spectral information from segment 4 of the Kelso Dunes flight. Both successfully identified at least three distinct spectral signatures, but neither has positively identified a specific material.

Kieffer, Hugh H.↗
NASA NTRS2011

Titan's Aerosol and Condensation Cloud Properties in the Far-IR Between 2005 and 2010

Analyses of far-IR spectra between 20 and 560 cm(exp -1) (500 to 18 micron) recorded by the Cassini Composite Infrared Spectrometer (CIRS) yield the spectral dependence and the vertical distribution of Titan's photochemical aerosol and ice clouds. Titan's aerosol appears to be well mixed between the surface and an altitude of 300 km, with a spectral shape that does not change with latitude or time. The aerosol exhibits an extremely broad emission feature with a spectral peak at 140 cm(exp -1) (71 micron), which is not evident in laboratory simulated Titan aerosols (tholin). This low- energy aerosol emission feature may arise from low-energy molecules such as polycyclic aromatic hydrocarbons and/or nitrogenated aromatics. Unlike the vertically well-mixed aerosol, Titan's condensate clouds are located in highly restricted altitudes in the lower stratosphere, ranging between 60 and 100 km at low and moderate latitudes, to between 150 and 165 km at high northern latitudes during northern winter. Such clouds are located at altitudes where nitrile vapors are expected to condense and appear to be dominated by HCN and HC3N, which are the two most abundant nitriles in Titan's atmosphere. Associated with this ice cloud is a broad emission feature that spectrally peaks near 160 cm(exp -1) (62.5 micron). This ice composite appears to chemically change with altitude and latitude, probably as a result of differences in vapor abundance and condensation temperature, and the ice cloud appears to be global in extent. Both CIRS and the Huygens Descent Imager and Spectral Radiometer (DISR) show evidence of cloud layering in Titan's lower stratosphere. The 15 km difference in cloud altitude indicated by the two instruments suggests a difference in ice composition. CIRS also indicates a second ice cloud that exists at isolated latitudes and is consistent with hydrocarbon condensation above the tropopause. This cloud exhibits an emission feature that spectrally peaks near 80 cm(exp -1) (125 micron), possibly due to C2H6 ice or dominated by an ethane-acetylene composite ice, given that CzH6 then C2H2 are the two most abundant hydrocarbons next to methane in Titan's atmosphere.

Anderson, Carrie↗
NASA NTRS1993

Martian spectral units derived from ISM imaging spectrometer data

Based on results of the Viking mission, the soil layer of Mars has been thought to be fairly homogeneous and to consist of a mixture of as few as two components, a 'dark gray' basaltic material and a 'bright red' altered material. However, near-infrared reflectance spectra measured recently both telescopically and from spacecraft indicate compositional heterogeneity beyond what can be explained by just two components. In particular, data from the ISM imaging spectrometer, which observed much of the equatorial region at a spatial resolution of approximately 22 km, indicate spatial differences in the presence and abundance of Fe-containing phases, hydroxylated silicates, and H2O. The ISM data was used to define, characterize, and map soil 'units' based on their spectral properties. The spatial distribution of these 'units' were compared to morphologic, visible color, and thermal inertia features recognized in Viking data.

Murchie, S.↗
NASA NTRS2016

VLTI-AMBER Velocity-Resolved Aperture-Synthesis Imaging of Eta Carinae with a Spectral Resolution of 12 000: Studies of the Primary Star Wind and Innermost Wind-Wind Collision Zone

The mass loss from massive stars is not understood well. Eta Carinae is a unique object for studying the massive stellar wind during the luminous blue variable phase. It is also an eccentric binary with a period of 5.54 yr. The nature of both stars is uncertain, although we know from X-ray studies that there is a wind-wind collision whose properties change with orbital phase. Aims. We want to investigate the structure and kinematics of Car's primary star wind and wind-wind collision zone with a high spatial resolution of approx.6 mas (approx.14 au) and high spectral resolution of R = 12 000. Methods. Observations of Car were carried out with the ESO Very Large Telescope Interferometer (VLTI) and the AMBER instrument between approximately five and seven months before the August 2014 periastron passage. Velocity-resolved aperture-synthesis images were reconstructed from the spectrally dispersed interferograms. Interferometric studies can provide information on the binary orbit, the primary wind, and the wind collision. Results. We present velocity-resolved aperture-synthesis images reconstructed in more than 100 di erent spectral channels distributed across the Br(gamma) 2.166 micron emission line. The intensity distribution of the images strongly depends on wavelength. At wavelengths corresponding to radial velocities of approximately -140 to -376 km/s measured relative to line center, the intensity distribution has a fan-shaped structure. At the velocity of -277 km/s, the position angle of the symmetry axis of the fan is 126. The fan-shaped structure extends approximately 8.0 mas (approx.18:8 au) to the southeast and 5.8 mas (approx.13:6 au) to the northwest, measured along the symmetry axis at the 16% intensity contour. The shape of the intensity distributions suggests that the obtained images are the first direct images of the innermost wind-wind collision zone. Therefore, the observations provide velocity-dependent image structures that can be used to test three-dimensional hydrodynamical, radiative transfer models of the massive interacting winds of Eta Car.

Velocity-resolved aperture-synthesis images↗
NASA NTRS1989

An evaluation of imaging spectrometry for estimating forest canopy chemistry

High spectral resolution Airborne Imaging Spectrometer (AIS) data were acquired over 20 well-studied Wisconsin forest sites to evaluate the potential of remote sensing for estimating forest canopy chemistry. Intensive nutrient cycling research in these forests demonstrates that canopy lignin content is strongly related to measured annual nitrogen mineralization at the undisturbed sites and may serve as an accurate index for nitrogen cycling rates. Ground measurements were made of foliar biomass and canopy nitrogen and lignin content, the latter within two weeks of the AIS overflight. The spectral data were transformed using derivative techniques modified from laboratroy spectroscopy. Stepwise regression assisted in determining combinations of wavelengths most highly correlated with canopy chemistry and biomass. Strong correlations between AIS data and total canopy lignin content in deciduous forests and canopy lignin concentration (total lignin/biomass) in both deciduous and coniferous stands indicate that imaging spectrometry can be used to estimate canopy lignin content and, from that, the spatial distribution of annual nitrogen mineralization rates.

Wessman, Carol A.↗
NASA NTRS1992

Submillimeter, millimeter, and microwave spectral line catalogue, revision 3

A computer-accessible catalog of submillimeter, millimeter, and microwave spectral lines in the frequency range between 0 and 10,000 GHz (i.e., wavelengths longer than 30 micrometers) is described. The catalog can be used as a planning or as an aid in the identification and analysis of observed spectral lines. The information listed for each spectral line includes the frequency and its estimated error, the intensity, the lower state energy, and the quantum number assignment. This edition of the catalog has information on 206 atomic and molecular species and includes a total of 630,924 lines. The catalog was constructed by using theoretical least square fits of published spectral lines to accepted molecular models. The associated predictions and their estimated errors are based upon the resultant fitted parameters and their covariances. Future versions of this catalog will add more atoms and molecules and update the present listings as new data appear. The catalog is available as a magnetic data tape recorded in card images, with one card image per spectral line, from the National Space Science Data Center, located at Goddard Space Flight Center.

Pickett, H. M.↗
NASA NTRS2004

Far-Infrared Space Interferometers: Future Windows on Star and Planet Formation

Far-IR space interferometers will provide observational access to a spectral region containing many important cooling and diagnostic spectral lines and the bulk of the thermal emission from dust at angular scales critical to advancing our understanding of the star and planet formation process. We will describe concepts for the Space Infrared Interferometric Telescope (SPIRIT) and the Submillimeter Probe of the Evolution of Cosmic Structure (SPECS). Both of these candidate NASA missions are imaging and spectral Michelson interferometers operating in the wavelength range -40 - 800 microns. SPIRIT, which could be launched in a decade as a NASA Origins Probe, is built on a deployable boom and has a maximum baseline length of -30 - 50 m, yielding sub-arcsecond resolution in the far-IR. SPIRIT will thus provide far-IR/sub-mm measurements complementary to the near- and mid-IR measurements obtainable with the James Webb Space Telescope (JWST), and well matched to JWST observations in angular resolution. Ultimately SPECS, a NASA Vision Mission, will use formation flying to attain baseline lengths up to 1 km, and thus angular resolution comparable to that of the Hubble Space Telescope and the Atacama Large Millimeter Array. We will report preliminary results of the NASA-sponsored SPIRIT and SPECS mission studies, which are now underway.

Leisawitz, David↗
NASA NTRS2005

Multi-Band Large Format Infrared Imaging Arrays

Large-format and multi-band focal plane arrays (FPA) based on quantum well and quantum dot infrared photodetectors have been developed for various instruments such as imaging interferometers and hyperspectral imagers. The spectral response of these detectors are tailorable within the mid- and long-wavelength infrared bands.

infrared↗
NASA NTRS2018

The LUVOIR Surveyor: Decadal Mission Concept Update

The Large Ultraviolet/Optical/Infrared (LUVOIR) Science and Technology Definition Team (STDT) identified a broad range of science objectives for LUVOIR that include the direct imaging and spectral characterization of habitable exoplanets and an array of general astrophysics and Solar System observations. To meet these objectives, the LUVOIR Study Office completed the first design iteration of a 15-m segmented-aperture observatory that includes four serviceable instruments: the Extreme Coronagraph for Living Planetary Systems (ECLIPS); the LUVOIR UV Multi-object Spectrograph (LUMOS); the High Definition Imager (HDI); and Pollux, a high-resolution UV spectro-polarimeter being contributed by Centre National d'Etudes Spatiales (CNES). The study team is now executing a second design iteration to further improve upon the 15-m concept, while simultaneously studying a 9-m concept. In these proceedings, we provide an update on these architectures.

LUVOIR↗
NASA NTRS1974

Orange glass - Evidence for regional deposits of pyroclastic origin on the moon

Crystallized spheres of orange glass from Shorty Crater at the Apollo 17 site are shown by spectral reflectance data to be the characteristic ingredient of the dark mantling deposit of the Taurus-Littrow region. This deposit, mapped on spectral vidicon images taken using earth-based telescopes, apparently is thickest 50 km northwest of the Apollo 17 landing area, and has a gradational contact with the surrounding materials. The irregular areal distribution of the dark-mantle deposit and the gradational borders support conclusions based on laboratory studies of the orange soils that these are volcanic pyroclastic materials. Similar deposits are identified by spectral reflectance properties near Rima Bode, Schroeter W, Fauth H, and Higinus W. The same material is likely to occur at Sulpucius Gallus based on visual and photographic observations of orange soil. The apparently restricted occurrence of the orange-glass deposits in a belt along the edges of major mare basins implies structural control of volcanic vents and a possible deep-seated origin.

Adams, J. B.↗
NASA NTRS2006

Advanced Remote-sensing Imaging Emission Spectrometer (ARIES): AIRS Spectral Resolution with MODIS Spatial Resolution

This paper describes a space based instrument concept that will provide scientists with data needed to support key ongoing and future Earth System Science investigations. The measurement approach builds on the observations made by AIRS and MODIS and exceeds their capability with improved spatial and spectral resolution. This paper describes the expected products and the instrument concept that can meet those requirements.

spectrometers↗
DOE OSTI2020

Imaging broadband soft X-ray transmission-grating spectrograph for a wavelength range λ > 111 Å

A family of aperiodic Mo/Be multilayer mirrors was designed for maximum uniform reflectivity in the ranges 111 – 138, 111 – 150, 111 – 200 and 111 – 222 Å at normal radiation incidence. The simulations took into account the existence of Mo-on-Be and Be-on-Mo transition layers. It was shown that the reflectivity may be as high as 10% in an octave wavelength range of 111 – 222 Å. We demonstrate the operation of an imaging transmission-grating spectrograph with a broadband Mo/Be multilayer mirror with a uniform reflectivity in the wavelength range 111 – 138 Å synthesised at the Institute for the Physics of Microstructures, RAS. The spectrograph was used to record the line spectra of multiply charged fluorine and magnesium ions from a laser-produced plasma. The role of the grating support structure in the formation of spectral source images is discussed. The spatial resolution of 50 μm is demonstrated. (laser applications and other topics in quantum electronics)

36 MATERIALS SCIENCE↗
NASA NTRS2004

Tunable-Bandwidth Filter System

A tunable-bandwidth filter system (TBFS), now undergoing development, is intended to be part of a remote sensing multispectral imaging system that will operate in the visible and near infrared spectral region (wavelengths from 400 to 900 nm). Attributes of the TBFS include rapid tunability of the pass band over a wide wavelength range and high transmission efficiency. The TBFS is based on a unique integration of two pairs of broadband Raman reflection holographic filters with two rotating spherical lenses. In experiments, a prototype of the TBFS, was shown to be capable of spectral sampling of images in the visible range over a 200 nm spectral range with a spectral resolution of 30 nm. The figure depicts the optical layout of a prototype of the TBFS as part of a laboratory multispectral imaging system for the spectral sampling of color test images in two orthogonal polarizations. Each pair of broadband Raman reflection holographic filters is mounted at an equatorial plane between two halves of a spherical lens. The two filters in each pair are characterized by steep spectral slopes (equivalently, narrow spectral edges), no ripple or side lobes in their pass bands, and a few nanometers of non-overlapping wavelength range between their pass bands. Each spherical lens and thus the filter pair within it is rotated in order to rapidly tune its pass band. The rotations of are effected by electronically controlled, programmable, high-precision rotation stages. The rotations are coordinated by electronic circuits operating under overall supervision of a personal computer in order to obtain the desired variation of the overall pass bands with time. Embedding the filters inside the spherical lenses increases the range of the hologram incidence angles, making it possible to continuously tune the pass and stop bands of the filters over a wider wavelength range. In addition, each spherical lens also serves as part of the imaging optics: The telephoto lens focuses incoming light to a field stop that is also a focal point of each spherical lens. A correcting lens in front of the field stop compensates for the spherical aberration of the spherical lenses. The front surface of each spherical lens collimates the light coming from the field stop. After the collimated light passes through the filter in the spherical lens, the rear surface of the lens focuses the light onto a charge-coupled-device image detector.

Bailey, John W.↗
NASA NTRS2006

Tunable-Bandwidth Filter System

A tunable-bandwidth filter system (TBFS), now undergoing development, is intended to be part of a remote-sensing multispectral imaging system that will operate in the visible and near infrared spectral region (wavelengths from 400 to 900 nm). Attributes of the TBFS include rapid tunability of the pass band over a wide wavelength range and high transmission efficiency. The TBFS is based on a unique integration of two pairs of broadband Raman reflection holographic filters with two rotating spherical lenses. In experiments, a prototype of the TBFS was shown to be capable of spectral sampling of images in the visible range over a 200-nm spectral range with a spectral resolution of .30 nm. The figure depicts the optical layout of a prototype of the TBFS as part of a laboratory multispectral imaging system for the spectral sampling of color test images in two orthogonal polarizations. Each pair of broadband Raman reflection holographic filters is mounted at an equatorial plane between two halves of a spherical lens. The two filters in each pair are characterized by steep spectral slopes (equivalently, narrow spectral edges), no ripple or side lobes in their pass bands, and a few nanometers of non-overlapping wavelength range between their pass bands. Each spherical lens and thus the filter pair within it is rotated in order to rapidly tune its pass band. The rotations of the lenses are effected by electronically controlled, programmable, high-precision rotation stages. The rotations are coordinated by electronic circuits operating under overall supervision of a personal computer in order to obtain the desired variation of the overall pass bands with time. Embedding the filters inside the spherical lenses increases the range of the hologram incidence angles, making it possible to continuously tune the pass and stop bands of the filters over a wider wavelength range. In addition, each spherical lens also serves as part of the imaging optics: The telephoto lens focuses incoming light to a field stop that is also a focal point of each spherical lens. A correcting lens in front of the field stop compensates for the spherical aberration of the spherical lenses. The front surface of each spherical lens collimates the light coming from the field stop. After the collimated light passes through the filter in the spherical lens, the rear surface of the lens focuses the light onto a charge-coupled-device image detector.

Aye, Tin↗
NASA NTRS2013

High Resolution Surface Science at Mars

The proposed mission would place a 2.4 m telescope in orbit around Mars with two focal plane instruments to obtain the highest resolution images and spectral maps of the surface to date (3-10x better than current). This investigation would make major contributions to all of the Mars Program Goals: life, climate, geology and preparation for human presence.

imaging↗