Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Mid infraRed Instruments”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS2022

VLTI-MATISSE L- and N-Band Aperture-Synthesis Imaging of the Unclassified B[e] star FS Canis Majoris

Context. FS Canis Majoris (FS CMa, HD 45677) is an unclassified B[e] star surrounded by an inclined dust disk. The evolutionary stage of FS CMa is still debated. Perpendicular to the circumstellar disk, a bipolar outflow was detected. Infrared aperture-synthesis imaging provides us with a unique opportunity to study the disk structure. Aims. Our aim is to study the intensity distribution of the disk of FS CMa in the mid-infrared L and N bands. Methods. We performed aperture-synthesis imaging of FS CMa with the MATISSE instrument (Multi AperTure mid-Infrared SpectroScopic Experiment) in the low spectral resolution mode to obtain images in the L and N bands. We computed radiative transfer models that reproduce the L- and N-band intensity distributions of the resolved disks. Results. We present L- and N-band aperture-synthesis images of FS CMa reconstructed in the wavelength bands of 3.4–3.8 and 8.6–9.0 μm. In the L-band image, the inner rim region of an inclined circumstellar disk and the central object can be seen with a spatial resolution of 2.7 milliarcsec (mas). An inner disk cavity with an angular diameter of ~6 × 12 mas is resolved. The L-band disk consists of a bright northwestern (NW) disk region and a much fainter southeastern (SE) region. The images suggest that we are looking at the bright inner wall of the NW disk rim, which is on the far side of the disk. In the N band, only the bright NW disk region is seen. In addition to deriving the inclination and the inner disk radius, fitting the reconstructed brightness distributions via radiative transfer modelling allows one to constrain the innermost disk structure, in particular the shape of the inner disk rim.

techniques↗
NASA NTRS1998

Maintaining Flatness of a Large Aperture Potassium Bromide Beamsplitter through Mounting and Vibration

The Composite Infrared Spectrometer (CIRS) instrument on the Cassini Mission launched in October of 1997. The CIRS instrument contains a mid-infrared and a far-infrared interferometer and operates at 170 Kelvin. The mid-infrared interferometer is a Michelson- type Fourier transform spectrometer utilizing a 3 inch diameter potassium bromide beamsplitter/compensator pair. The potassium bromide elements were tested to verify effects of cooldown and vibration prior to integration into the instrument. The instrument was then aligned at ambient temperatures, tested cryogenically and re-verified after vibration. The stringent design optical figure requirements for the beamsplitter and compensator included fabrication errors, mounting stresses and vibration load effects. This paper describes the challenges encountered in mounting the elements to minimize distortion and to survive vibration.

Losch, Patricia↗
NASA NTRS1998

Maintaining Flatness of a Large Aperture Potassium Bromide Beamsplitter Through Mounting and Vibration

The Composite Infrared Spectrometer (CIRS) instrument on the Cassini Mission launched in October of 1997. The CIRS instrument contains a mid-infrared (MIR) and a far-infrared interferometer (FIR) and operates at 170 Kelvin. The MIR is a Michelson Fourier transform spectrometer utilizing a 76 mm (3 inch) diameter potassium bromide beamsplitter and compensator pair. The potassium bromide elements were tested to verify effects of cooldown and vibration prior to integration into the instrument. The instrument was then aligned at ambient temperatures, tested cryogenically and re-verified after vibration. 'Me stringent design optical figure requirements for the beamsplitter and compensator included fabrication errors, mounting stresses and vibration load effects. This paper describes the challenges encountered in mounting the elements to minimize distortion and to survive vibration.

Losch, Patricia↗
NASA NTRS2009

Mobile Instruments Measure Atmospheric Pollutants

As a part of NASA's active research of the Earth s atmosphere, which has included missions such as the Atmospheric Laboratory of Applications and Science (ATLAS, launched in 1992) and the Total Ozone Mapping Spectrometer (TOMS, launched on the Earth Probe satellite in 1996), the Agency also performs ground-based air pollution research. The ability to measure trace amounts of airborne pollutants precisely and quickly is important for determining natural patterns and human effects on global warming and air pollution, but until recent advances in field-grade spectroscopic instrumentation, this rapid, accurate data collection was limited and extremely difficult. In order to understand causes of climate change and airborne pollution, NASA has supported the development of compact, low power, rapid response instruments operating in the mid-infrared "molecular fingerprint" portion of the electromagnetic spectrum. These instruments, which measure atmospheric trace gases and airborne particles, can be deployed in mobile laboratories - customized ground vehicles, typically - to map distributions of pollutants in real time. The instruments must be rugged enough to operate rapidly and accurately, despite frequent jostling that can misalign, damage, or disconnect sensitive components. By measuring quickly while moving through an environment, a mobile laboratory can correlate data and geographic points, revealing patterns in the environment s pollutants. Rapid pollutant measurements also enable direct determination of pollutant sources and sinks (mechanisms that remove greenhouse gases and pollutants), providing information critical to understanding and managing atmospheric greenhouse gas and air pollutant concentrations.

Source record↗
NASA NTRS1998

Mid-Infrared Astronomy with the NGST

We present an overview of the science capabilities enabled by a mid-infrared camera/spectrometer on board the NGST. Even without full mid-IR optimization, a mid-infrared (5-30 microns) instrument on the NGST will be orders of magnitude more sensitive than any equivalent ground-based instrument/telescope combination. In the extragalactic arena, the mid-IR region is critical for a complete understanding of the or high-redshift universe, dusty star-formation regions at low and high redshifts, and starburst vs. AGN discrimination. In the local universe, great strides forward can be made using mid-IR imaging, spectroscopy, and coronagraphy of dusty and rocky disks of all ages, from protostellar to remnant debris disks. Near-neighbor detection and characterization can also be greatly advanced by mid-infrared observations.

Serabyn, E.↗
NASA NTRS1987

Mid-infrared spectroscopic investigation

Mid-infrared spectroscopic research efforts are discussed. The development of a new instrumentation to permit advanced measurements in the mid-infrared region of the spectrum, the development of a special library of well-characterized mineral and rock specimens for interpretation of remote sensing data, and cooperative measurements of the spectral signatures of analogues of materials that may be present on the surfaces of asteroids, planets or their Moons are discussed.

Salisbury, John W.↗
NASA NTRS2012

Radiation Hard Bandpass Filters for Mid- to Far-IR Planetary Instruments

We present a novel method to fabricate compact metal mesh bandpass filters for use in mid- to far-infrared planetary instruments operating in the 20-600 micron wavelength spectral regime. Our target applications include thermal mapping instruments on ESA's JUICE as well as on a de-scoped JEO. These filters are novel because they are compact, customizable, free-standing copper mesh resonant bandpass filters with micromachined silicon support frames. The filters are well suited for thermal mapping mission to the outer planets and their moons because the filter material is radiation hard. Furthermore, the silicon support frame allows for effective hybridization with sensors made on silicon substrates. Using a Fourier Transform Spectrometer, we have demonstrated high transmittance within the passband as well as good out-of-band rejection [1]. In addition, we have developed a unique method of filter stacking in order to increase the bandwidth and sharpen the roll-off of the filters. This method allows one to reliably control the spacing between filters to within 2 microns. Furthermore, our method allows for reliable control over the relative position and orienta-tion between the shared faces of the filters.

Brown, Ari D.↗
NASA NTRS1998

Throughput of the Composite Infrared Spectrometer (CIRS) Mid Infrared (MIR) Channel for the Cassini Mission to Saturn

The Composite Infrared Spectrometer (CIRS) of the Cassini mission to Saturn has two interferometers covering the far infrared and mid infrared wavelength region. The instrument was aligned at ambient temperature, but operates at 170 Kelvin and has challenging interferometric alignment tolerances. Cryogenic alignment tests of the instrument indicate that it should suffer minimal degradation due to the cooldown from ambient to operational temperature. System level tests performed by the calibration team indicated a lower than expected signal level on the MIR channel, while providing ambiguous optical throughput data. Therefore it became imperative to develop a metric that could be used to determine the instrument performance at both the instrument and system levels, at ambient and cryogenic temperature. Modulation efficiency and throughput measurements were performed and new analytical models developed to evaluate the status of the instrument. Empirical and analytical data were eventually reconciled and deviations from the design values explained.

Hagopian, John G.↗
NASA NTRS2012

Multi-Color QWIP FPAs for Hyperspectral Thermal Emission Instruments

Infrared focal plane arrays (FPAs) covering broad mid- and long-IR spectral ranges are the central parts of the spectroscopic and imaging instruments in several Earth and planetary science missions. To be implemented in the space instrument these FPAs need to be large-format, uniform, reproducible, low-cost, low 1/f noise, and radiation hard. Quantum Well Infrared Photodetectors (QWIPs), which possess all needed characteristics, have a great potential for implementation in the space instruments. However a standard QWIP has only a relatively narrow spectral coverage. A multi-color QWIP, which is compromised of two or more detector stacks, can to be used to cover the broad spectral range of interest. We will discuss our recent work on development of multi-color QWIP for Hyperspectral Thermal Emission Spectrometer instruments. We developed QWIP compromising of two stacks centered at 9 and 10.5 ?m, and featuring 9 grating regions optimized to maximize the responsivity in the individual subbands across the 7.5-12 ?m spectral range. The demonstrated 1024x1024 QWIP FPA exhibited excellent performance with operability exceeding 99% and noise equivalent differential temperature of less than 15 mK across the entire 7.5-12 ?m spectral range.

Infrared focal plane arrays (FPAs)↗
NASA NTRS2013

Multi-color QWIP FPAs for hyperspectral thermal emission instruments

Infrared focal plane arrays (FPAs) covering broad mid- and long-IR spectral ranges are the central parts of the spectroscopic and imaging instruments in several Earth and planetary science missions. To be implemented in the space instrument these FPAs need to be large-format, uniform, reproducible, low-cost, low 1/f noise, and radiation hard. Quantum Well Infrared Photodetectors (QWIPs), which possess all needed characteristics, have a great potential for implementation in the space instruments. However a standard QWIP has only a relatively narrow spectral coverage. A multi-color QWIP, which is compromised of two or more detector stacks, can to be used to cover the broad spectral range of interest. We will discuss our recent work on development of multi-color QWIP for Hyperspectral Thermal Emission Spectrometer instruments. We developed QWIP compromising of two stacks centered at 9 and 10.5 μm, and featuring 9 grating regions optimized to maximize the responsivity in the individual subbands across the 7.5-12 μm spectral range. The demonstrated 1024x1024 QWIP FPA exhibited excellent performance with operability exceeding 99% and noise equivalent differential temperature of less than 15 mK across the entire 7.5-12 μm spectral range.

Gunapala, Sarath D.↗
NASA NTRS2018

Star & Planet Formation Studies and Opportunities with SOFIA

Star formation, the most fundamental process in the universe, is linked to planet formation and thus to the origin and evolution of life. We have a general outline of how planets and stars form, yet unraveling the details of the physics and chemistry continues to challenge us. The infrared and submillimeter part of the spectrum hold the most promise for studying the beginnings of star formation. The observational landscape recently shaped by Spitzer, Herschel and ALMA, continues to challenge our current theories. SOFIA, the Stratospheric Observatory for Infrared Astronomy, equipped with state-of-the-art infrared instrumentation to a vantage point at 45,000 feet (13.7 kilometers) flight altitude that is above 99.9 percent of the Earth's water vapor, enables observations in the infrared through terahertz frequencies not possible from the ground. SOFIA is a community observatory, about to start its sixth annual observing cycle. My talk will focus on recent results in advancing star and planet formation processes using SOFIAʼs imaging and polarimetric capabilities, and the upcoming science enabled by the 3rd generation instrument High-Resolution Mid-Infrared Spectrometer (HIRMES) to be commissioned in 2019. I will show how mid-infrared imaging is used to test massive star formation theories, how far-infrared polarimetry on sub-parsec scales is directly testing the role of magnetic fields in molecular clouds, and how velocity-resolved high-resolution spectroscopy will push forward our understanding of proto-planetary disk science. I will also summarize upcoming opportunities with the SOFIA observatory. For the latest news about your flying observatory, see https://sofia.usra.edu/.

Star formation↗
NASA NTRS2018

Applying the SOFIA Coordinate System to the HIRMES Instrument

The High-resolution Mid-infrared Spectrometer (HIRMES) will be in-flight aboard the Stratospheric Observatory for Infrared Astronomy (SOFIA) in late 2019, which will allow for observations of the structure and evolution of protoplanetary disks. SOFIA has a different coordinate system from the system being used to build HIRMES and needs to be defined and applied to HIRMES. This is necessary because the first mirror, which is aiming the incoming light onto the slit wheel by allowing for tip and tilt adjustments, cannot rotate. Thus, the SOFIA coordinate system allows for this additional degree of freedom and allows for the slit wheel to be in line with the telescope. Using a laser radar, multiple measurements around the instrument were taken of tooling balls, which quantified an uncertainty with the measurements. Also, a laser radar was used to scan the entirety of the instrument. The center of the front flange was determined using the measurements and scans of the instrument, which was used to determine the origin of the SOFIA coordinate system and its uncertainty. By knowing the center of the front flange, an off-center, rotated coordinate system was created, matching the mechanics' schematics for the system. Going forward, this coordinate system will allow for continued alignment of the instrument in preparation for flight and for accurate measurements when aboard SOFIA.

Wraback, Elizabeth↗
NASA NTRS1989

The Cassini mission: Infrared and microwave spectroscopic measurements

The Cassini Orbiter and Titan Probe model payloads include a number of infrared and microwave instruments. This document describes: (1) the fundamental scientific objectives for Saturn and Titan which can be addressed by infrared and microwave instrumentation, (2) the instrument requirements and the accompanying instruments, and (3) the synergism resulting from the comprehensive coverage of the total infrared and microwave spectrum by the complement of individual instruments. The baseline consists of four instruments on the orbiter and two on the Titan probe. The orbiter infrared instruments are: (1) a microwave spectrometer and radiometer; (2) a far to mid-infrared spectrometer; (3) a pressure modulation gas correlation spectrometer, and (4) a near-infrared grating spectrometer. The two Titan probe infrared instruments are: (1) a near-infrared instrument, and (2) a tunable diode laser infrared absorption spectrometer and nephelometer.

Kunde, V. G.↗
NASA NTRS2017

Multi-Wavelength Laser Transmitter for the Two-Step Laser Time-of-Flight Mass Spectrometer

Missions to diverse Outer Solar System bodies will require investigations that can detect a wide range of organics in complex mixtures, determine the structure of selected molecules, and provide powerful insights into their origin and evolution. Previous studies from remote spectroscopy of the Outer Solar System showed a diverse population of macromolecular species that are likely to include aromatic and conjugated hydrocarbons with varying degrees of methylation and nitrile incorporation. In situ exploration of Titan's upper atmosphere via mass and plasma spectrometry has revealed a complex mixture of organics. Similar material is expected on the Ice Giants, their moons, and other Outer Solar System bodies, where it may subsequently be deposited onto surface ices. It is evident that the detection of organics on other planetary surfaces provides insight into the chemical and geological evolution of a Solar System body of interest and can inform our understanding of its potential habitability. We have developed a prototype two-step laser desorption/ionization time-of-flight mass spectrometer (L2MS) instrument by exploiting the resonance-enhanced desorption of analyte. We have successfully demonstrated the ability of the L2MS to detect hydrocarbons in organically-doped analog minerals, including cryogenic Ocean World-relevant ices and mixtures. The L2MS instrument operates by generating a neutral plume of desorbed analyte with an IR desorption laser pulse, followed at a delay by a ultraviolet (UV) laser pulse, ionizing the plume. Desorption of the analyte, including trace organic species, may be enhanced by selecting the wavelength of the IR desorption laser to coincide with IR absorption features associated with vibration transitions of minerals or organic functional groups. In this effort, a preliminary laser developed for the instrument uses a breadboard mid-infrared (MIR) desorption laser operating at a discrete 3.475 μm wavelength, and a breadboard UV ionization laser operating at a wavelength of 266 nm. The MIR wavelength was selected to overlap the C-H stretch vibrational transition of certain aromatic hydrocarbons, and the UV wavelength provides additional selectivity to aromatic species via UV resonance-enhanced multiphoton ionization effects. The use of distinct laser wavelengths allows efficient coupling to the vibrational and electronic spectra of the analyte in independent desorption and ionization steps, mitigating excess energy that can lead to fragmentation during the ionization process and leading to selectivity that can aid in data interpretation.

Yu, Anthony W.↗
NASA NTRS1991

Derivation of mid-infrared (5-25 microns) optical constants of some silicates and palagonite

Recent reports concerning the mid-infrared reflectance properties of silicates coupled with recent observations of the Earth and other planets in the mid-infrared and the planned Thermal Emission Spectrometer scheduled as an instrument to be included on the Mars Observer all illustrate the increasing interest in the optical properties of materials in the mid-infrared and their direct application to remote sensing observations of other planetary surfaces. As the laboratory and observational data increase they will ultimately be modeled to aid in the understanding of the composition mineralogy, and distribution of the surface and atmospheric constituents on these bodies. In order to facilitate such quantitative analyses, knowledge regarding the optical constants (real (n) and imaginary (k) indices of refraction) of a wide variety of pertinent materials is required. Examples of the application of such quantitative analyses to the interpretation of Martian surface and atmospheric constituents, based on the optical constants of minerals, are presented. This study was initially conceived in order to aid in the interpretation of Martian surface and atmospheric aerosol mineralogy. As a result, the minerals included are biased toward samples which represent hydrated and hydroxylated silicates. These include the Al and Mg end members of the 1:1 layer lattice silicates, kaolinite and serpentine, respectively; an Al-bearing 2:1 layer lattice silicate, pyrophyllite; the Mg and Al smectite clays saponite and montmorillonite, respectively; and a palagonite, typically a poorly characterized alteration product of basaltic glass. The reflectivities of all samples were determined by placing them at the focus of a near-normal reflective attachment located in a Fourier transform spectrometer. To derive the optical constants of a material as a function of wavelength, researchers used the commonly employed technique of dispersion analysis.

Roush, T. L.↗
NASA NTRS1983

Diffraction-limited spatial resolution of circumstellar shells at 10 microns

A new spatial array instrument provided diffraction-limited mid-infrared intensity profiles of the type-M supergiant stars alpha Orionis and alpha Scorpii, both of which are known to exhibit excess 10 microns radiation due to the presence of circumstellar dust shells. In the case of alpha Ori, there is a marked asymmetry in the dust distribution, with peak intensity of dust emission a distance of 0.9 inches from the star.

Bloemhof, E. E.↗
NASA NTRS1990

Infrared measurements of atmospheric constituents

The objective of this program is to obtain data concerning the concentration versus altitude of various constituents of interest in the photochemistry of the stratospheric ozone layer. Data pertinent to this objective are obtained using balloon-borne instruments to measure the atmospheric transmission and emission in the mid infrared. In addition to obtaining constituent profile information, the spectral data obtained are also used to identify absorption or emission features which may interfere with the retrieval of constituent data from satellite instruments using lower spectral resolution. The spectral resolution obtained with the solar spectral system is 0.0025 cm(exp -1) and represents about a factor of 5 greater resolution than any solar spectra previously obtained in this spectral region. As a result of the increase in spectral resolution, a large number of features are observed in these spectra which were not observed in previous studies. Identification and analysis of these features is in progress. The results of this analysis to date shows a number of HNO3 features which have not been observed before, and these occur where they will interfere with the retrieval of other constituents. An example of the interference is the occurrence of features in the 780.2 cm(exp -1) region which overlap the ClONO2 feature which will be used for retrieval of ClONO2 by the CLAES instrument on UARS. A number of features due to COF2 were also identified in the 1250 cm(exp -1) region which may interfere with retrieval of N2O5.

Murcray, David G.↗