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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 703 records · Page 39
All sourcesNASA NTRSDOE OSTI
NASA NTRS2006

Hematite at Meridiani Planum and Gusev Crater as identified by the Moessbauer Spectrometer MIMOS II

The Moessbauer (MB) spectrometers on the MER rovers Opportunity and Spirit, which landed on Mars in January 2004, have identified the iron-containing mineral hematite (a-Fe2O3) at both landing sites. On Earth, hematite can occur either by itself or with other iron oxides as massive deposits, in veins , and as particles dispersed through a silicate or other matrix material. Hematite particle size can range from nanophase (superparamagnetic) to multidomain and particle shape ranges from equant to acicular to platy. Fine-grained hematite is red in color and is a pigmenting agent. Coarse-grained hematite can be spectrally neutral (gray) at visible wavelengths. Substitutional impurities, particularly Al, are common in hematite. Chemically pure, coarse-grained, and well-crystalline hematite has a magnetic transition (the Morin transition) at ~260 K. Moessbauer spectra, recorded as a function of temperature, provide a way to characterize Martian hematite with respect to some of the physical and chemical characteristics. At Meridiani Planum besides the iron-sulfate mineral jarosite also the Fe-oxide hematite has been identified by the Moessbauer spectrometer, mainly in three distinct types of reservoir: - outcrop matrix material dominated by the mineral jarosite in the MB spectrum, certain basaltic soils, and mm-sized spherules dubbed blueberries. Moessbauer spectra of each reservoir yield a distinct set of hyperfine parameters for hematite, suggesting different degrees of crystallinity and particle size. The hematite found by MB instrument MIMOS II in the outcrop material shows the Morin transition at relatively high temperatures (ca. 250 K) which is an indication of pure and well-crystallized hematite. The source of the hematite in the Blueberries as identified by Moessbauer spectroscopy, and also by MiniTES, is not known. These spherules, covering nearly the whole landing site area (Eagle crater, plains, Endurance crater), may be concretions formed in the outcrop involving aqueous processes. They are dispersed throughout the hematite containing jarositic outcrop material. According to Moessbauer analysis the dominating iron-bearing mineral in the spherules is hematite, and jarosite not been detected so far in significant amounts. But there are some places with hematite showing characteristics different from the hematite described above: (1) the soil at B023_HematiteSlope_Hema2 has some blueberries, but the MB did not seem to intercept any. The temperature dependence of its MB parameters are different from those of blueberries. (2) B049_RasberryNewton_Filling shows a unique Hm MB signature, as well as (3) B051_RealSharksTooth_Enamel1.

Klingelhoefer, G.↗
NASA NTRS1993

Imaging Spectrometer Using a Liquid Crystal Tunable Filter

A demonstration imaging spectrometer using a liquid crystal tunable filter (LCTF) was built and tested on a hot air balloon platform. The LCTF is a tunable polarization interference or Lyot filter. The LCTF enables a small, light weight, low power, band sequential imaging spectrometer design.

Imaging↗
NASA NTRS2006

The Suzaku High Resolution X-ray Spectrometer

The high resolution X-Ray Spectrometer (XRS) has been designed to provide the Suzaku Observatory with very high spectral resolution, non-dispersive spectroscopy from 0.3 to 12 keV. This energy range encompasses the most diagnostically-rich part of the x-ray band. The sensor consists of a 32 channel array of x-ray of microcalorimeters, each with an energy resolution of about 6 eV. The very low temperature required for operation of the array (60 mK) is provided by a four-stage cooling system containing a single stage ADR, superfluid He Cryostat, solid Ne Dewar, and a single-stage Stirling-cycle cooler. The Suzaku/XRS is the first orbiting x-ray microcalorimeter spectrometer and has been designed to last more than three years in orbit. The early verification phase of the mission demonstrated that the instrument was working properly and that the cryogen consumption rate was low enough to ensure a mission lifetime exceeding 3 years. However, the liquid He cryogen was completely vaporized two weeks after opening the dewar guard vacuum vent. The problem has been traced to inadequate venting of the dewar He and Ne gases out of the spacecraft into space. In this paper we present the design of the XRS instrument and describe the in-flight performance.

Kelley, Richard L.↗
NASA NTRS2007

Potential for Measurement of Trace Volatile Organic Compounds in Closed Environments Using Gas Chromatograph/Differential Mobility Spectrometer

For nearly 3.5 years, the Volatile Organic Analyzer (VOA) has routinely analyzed the International Space Station (ISS) atmosphere for a target list of approximately 20 volatile organic compounds (VOCs). Additionally, an early prototype of the VOA collected data aboard submarines in two separate trials. Comparison of the data collected on ISS and submarines showed a surprising similarity in the atmospheres of the two environments. Furthermore, in both cases it was demonstrated that the VOA data can detect hardware issues unrelated to crew health. Finally, it was also clear in both operations that the VOA s size and resource consumption were major disadvantages that would restrict its use in the future. The VOA showed the value of measuring VOCs in closed environments, but it had to be shrunk if it was to be considered for future operations in these environments that are characterized by cramped spaces and limited resources. The Sionex Microanalyzer is a fraction of the VOA s size and this instrument seems capable of maintaining or improving upon the analytical performance of the VOA. The two design improvements that led to a smaller, less complex instrument are the Microanalyzer s use of recirculated air as the gas chromatograph s carrier gas and a micromachined detector. Although the VOA s ion mobility spectrometer and the Microanalyzer s differential mobility spectrometer (DMS) are related detector technologies, the DMS was more amenable to micromachining. This paper will present data from the initial assessment of the Microanalyzer. The instrument was challenged with mixtures that simulated the VOCs typically detected in closed-environment atmospheres.

Limero, Thomas↗
NASA NTRS2006

Implementation of Cloud Retrievals for Tropospheric Emission Spectrometer (TES) Atmospheric Retrievals: Part 1. Description and Characterization of Errors on Trace Gas Retrievals

We develop an approach to estimate and characterize trace gas retrievals in the presence of clouds in high spectral measurements of upwelling radiance in the infrared spectral region (650-2260/cm). The radiance contribution of clouds is parameterized in terms of a set of frequency-dependent nonscattering optical depths and a cloud height. These cloud parameters are retrieved jointly with surface temperature, emissivity, atmospheric temperature, and trace gases such as ozone from spectral data. We demonstrate the application of this approach using data from the Tropospheric Emission Spectrometer (TES) and test data simulated with a scattering radiative transfer model. We show the value of this approach in that it results in accurate estimates of errors for trace gas retrievals, and the retrieved values improve over the initial guess for a wide range of cloud conditions. Comparisons are made between TES retrievals of ozone, temperature, and water to model fields from the Global Modeling and Assimilation Office (GMAO), temperature retrievals from the Atmospheric Infrared Sounder (AIRS), tropospheric ozone columns from the Goddard Earth Observing System (GEOS) GEOS-Chem, and ozone retrievals from the Total Ozone Mapping Spectrometer (TOMS). In each of these cases, this cloud retrieval approach does not introduce observable biases into TES retrievals.

aerosols↗
NASA NTRS1982

Automated mass spectrometer analysis system

An automated mass spectrometer analysis system is disclosed, in which samples are automatically processed in a sample processor and converted into volatilizable samples, or their characteristic volatilizable derivatives. Each volatilizable sample is sequentially volatilized and analyzed in a double focusing mass spectrometer, whose output is in the form of separate ion beams all of which are simultaneously focused in a focal plane. Each ion beam is indicative of a different sample component or different fragments of one or more sample components and the beam intensity is related to the relative abundance of the sample component. The system includes an electro-optical ion detector which automatically and simultaneously converts the ion beams, first into electron beams which in turn produce a related image which is transferred to the target of a vilicon unit. The latter converts the images into electrical signals which are supplied to a data processor, whose output is a list of the components of the analyzed sample and their abundances. The system is under the control of a master control unit, which in addition to monitoring and controlling various power sources, controls the automatic operation of the system under expected and some unexpected conditions and further protects various critical parts of the system from damage due to particularly abnormal conditions.

Kuppermann, Aron↗
NASA NTRS2002

Driving a quadrupole mass spectrometer via an isolating stage

Driving a quadrupole mass spectrometer includes obtaining an air core transformer with a primary and a secondary, matching the secondary to the mass spectrometer, and driving the primary based on first and second voltage levels. Driving of the primary is via an isolating stage that minimizes low level drive signal coupling.

Chutjian, Ara↗
NASA NTRS2003

Quadrupole mass spectrometer driver with higher signal levels

Driving a quadrapole mass spectrometer includes obtaining an air core transformer with a primary and a secondary, matching the secondary to the mass spectrometer, and driving the primary based on first and second voltage levels. Driving of the primary is via an isolating stage that minimizes low level drive signal coupling.

Chutjian, Ara↗
NASA NTRS1978

Automated mass spectrometer analysis system

An automated mass spectrometer analysis system is disclosed, in which samples are automatically processed in a sample processor and converted into volatilizable samples, or their characteristic volatilizable derivatives. Each volatizable sample is sequentially volatilized and analyzed in a double focusing mass spectrometer, whose output is in the form of separate ion beams all of which are simultaneously focused in a focal plane. Each ion beam is indicative of a different sample component or different fragments of one or more sample components and the beam intensity is related to the relative abundance of the sample component. The system includes an electro-optical ion detector which automatically and simultaneously converts the ion beams, first into electron beams which in turn produce a related image which is transferred to the target of a vidicon unit. The latter converts the images into electrical signals which are supplied to a data processor, whose output is a list of the components of the analyzed sample and their abundances. The system is under the control of a master control unit, which in addition to monitoring and controlling various power sources, controls the automatic operation of the system under expected and some unexpected conditions and further protects various critical parts of the system from damage due to particularly abnormal conditions.

Boettger, Heinz G.↗
NASA NTRS2008

The Miniaturized Moessbauer Spectrometers MIMOS II on MER: Four Years of Operation - A Summary

The two Miniaturized Moessbauer Spectrometers (MIMOS II) on board the two Mars Exploration Rovers Spirit and Opportunity have now been collecting important scientific data for more than four years. The spectrometers provide information about Fe-bearing mineral phases and determine Fe oxidation states. The total amount of targets analized exceeds 600, the total integration time exceeds 260 days for both rovers. Since landing, more than five half-lives of the Co-57 MB sources have past (intensity at the time of landing approx. 150 mCi). Current integration times are about 50 hours in order to achieve reasonable statistics as opposed to 8 hours at the beginning of the mission. In total, 13 different mineral phases were detected: Olivine, pyroxene, hematite, magnetite and nanophase ferric oxide were detected at both landing sites. At Gusev, ilmenite, goethite, a ferric sulfate phase and a yet unassigned phase (in the rock Fuzzy Smith) were detected. At Meridiani, jarosite, metallic iron in meteoritic samples (kamacite), troilite, and an unassigned ferric phase were detected. Jarosite and goethite are of special interest, as these minerals are indicators for water activity. In this abstract, an overview of Moessbauer results will be given, with a focus on data obtained since the last martian winter. The MER mission has proven that Moessbauer spectroscopy is a valuable tool for the in situ exploration of extraterrestrial bodies and for the study of Febearing samples. The experience gained through the MER mission makes MIMOS II a obvious choice for future missions to Mars and other targets. Currently, MIMOS II is on the scientific payload of two approved future missions: Phobos Grunt (Russian Space Agency; 2009) and ExoMars (European Space Agency; 2013).

Fleischer, I.↗
NASA NTRS2007

Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS): Imaging and Tracking Capability

The geosynchronous-imaging Fourier transform spectrometer (GIFTS) engineering demonstration unit (EDU) is an imaging infrared spectrometer designed for atmospheric soundings. It measures the infrared spectrum in two spectral bands (14.6 to 8.8 microns, 6.0 to 4.4 microns) using two 128 128 detector arrays with a spectral resolution of 0.57/cm with a scan duration of approx. 11 seconds. From a geosynchronous orbit, the instrument will have the capability of taking successive measurements of such data to scan desired regions of the globe, from which atmospheric status, cloud parameters, wind field profiles, and other derived products can be retrieved. The GIFTS EDU provides a flexible and accurate testbed for the new challenges of the emerging hyperspectral era. The EDU ground-based measurement experiment, held in Logan, Utah during September 2006, demonstrated its extensive capabilities and potential for geosynchronous and other applications (e.g., Earth observing environmental measurements). This paper addresses the experiment objectives and overall performance of the sensor system with a focus on the GIFTS EDU imaging capability and proof of the GIFTS measurement concept.

Zhou, D. K.↗
NASA NTRS2006

Two Years of Chemical Sampling on Meridiani Planum by the Alpha Particle X-Ray Spectrometer Onboard the Mars Exploration Rover Opportunity

For over two terrestrial years, the Mars Exploration Rover Opportunity has been exploring the martian surface at Meridiani Planum using the Athena instrument payload [1], including the Alpha Particle X-Ray Spectrometer (APXS). The APXS has a small sensor head that is mounted on the robotic arm of the rover. The chemistry, mineralogy and morphology of selected samples were investigated by the APXS along with the Moessbauer Spectrometer (MB) and the Microscopic Imager (MI). The Rock Abrasion Tool (RAT) provided the possibility to dust and/or abrade rock surfaces down to several millimeters to expose fresh material for analysis. We report here on APXS data gathered along the nearly 6-kilometers long traverse in craters and plains of Meridiani.

Bruckner, J.↗
NASA NTRS2007

Ground-Based Measurement Experiment and First Results with Geosynchronous-Imaging Fourier Transform Spectrometer Engineering Demonstration Unit

The geosynchronous-imaging Fourier transform spectrometer (GIFTS) engineering demonstration unit (EDU) is an imaging infrared spectrometer designed for atmospheric soundings. It measures the infrared spectrum in two spectral bands (14.6 to 8.8 microns, 6.0 to 4.4 microns) using two 128 x 128 detector arrays with a spectral resolution of 0.57 cm(exp -1) with a scan duration of approximately 11 seconds. From a geosynchronous orbit, the instrument will have the capability of taking successive measurements of such data to scan desired regions of the globe, from which atmospheric status, cloud parameters, wind field profiles, and other derived products can be retrieved. The GIFTS EDU provides a flexible and accurate testbed for the new challenges of the emerging hyperspectral era. The EDU ground-based measurement experiment, held in Logan, Utah during September 2006, demonstrated its extensive capabilities and potential for geosynchronous and other applications (e.g., Earth observing environmental measurements). This paper addresses the experiment objectives and overall performance of the sensor system with a focus on the GIFTS EDU imaging capability and proof of the GIFTS measurement concept.

Zhou, Daniel K.↗
NASA NTRS2008

Calculations for Calibration of a Mass Spectrometer

A computer program performs calculations to calibrate a quadrupole mass spectrometer in an instrumentation system for identifying trace amounts of organic chemicals in air. In the operation of the mass spectrometer, the mass-to-charge ratio (m/z) of ions being counted at a given instant of time is a function of the instantaneous value of a repeating ramp voltage waveform applied to electrodes. The count rate as a function of time can be converted to an m/z spectrum (equivalent to a mass spectrum for singly charged ions), provided that a calibration of m/z is available. The present computer program can perform the calibration in either or both of two ways: (1) Following a data-based approach, it can utilize the count-rate peaks and the times thereof measured when fed with air containing known organic compounds. (2) It can utilize a theoretical proportionality between the instantaneous m/z and the instantaneous value of an oscillating applied voltage. The program can also estimate the error of the calibration performed by the data-based approach. If calibrations are performed in both ways, then the results can be compared to obtain further estimates of errors.

Lee, Seungwon↗
NASA NTRS2008

Compact Two-Dimensional Spectrometer Optics

The figure is a simplified depiction of a proposed spectrometer optical unit that would be suitable for incorporation into a remote-sensing instrumentation system. Relative to prior spectrometer optical assemblies, this unit would be compact and simple, largely by virtue of its predominantly two-dimensional character. The proposed unit would be a combination of two optical components. One component would be an arrayed-waveguide grating (AWG) an integrated-optics device, developed for use in wavelength multiplexing in telecommunications. The other component would be a diffraction grating superimposed on part of the AWG. The function of an AWG is conceptually simple. Input light propagates along a single-mode optical waveguide to a point where it is split to propagate along some number (N) of side-by-side waveguides. The lengths of the optical paths along these waveguides differ such that, considering the paths in a sequence proceeding across the array of waveguides, the path length increases linearly. These waveguides launch quasi-free-space waves into a planar waveguide-coupling region. The waves propagate through this region to interfere onto an array of output waveguides. Through proper choice of key design parameters (waveguide lengths, size and shape of the waveguide coupling region, and lateral distances between waveguides), one can cause the input light to be channeled into wavelength bins nominally corresponding to the output waveguides.

Hong, John↗
NASA NTRS2009

The SOFIA/SAFIRE Far-Infrared Spectrometer: Highlighting Submillimeter Astrophysics and Technology

The Submillimeter and Far-InfraRed Experiment (SAFIRE) on the SOFIA airborne observatory is an imaging spectrometer for wavelengths between 28 microns and 440 microns. Our design is a dual-band long-slit grating spectrometer, which provides broadband (approx. 4000 km/s) observations in two lines simultaneously over a field of view roughly 10" wide by 320" long. The low backgrounds in spectroscopy require very sensitive detectors with noise equivalent powers of order 10(exp -18) W/square root of Hz. We are developing a kilopixel, filled detector array for SAFIRE in a 32 x 40 format. The detector consists of a transition edge sensor (TES) bolometer array, a per-pixel broadband absorbing backshort array, and a NIST SQUID multiplexer readout array. This general type of array has been used successfully in the GISMO instrument, so we extrapolate to the sensitivity needed for airborne spectroscopy. Much of the cryogenic, electronics, and software infrastructure for SAFIRE have been developed. I provide here an overview of the progress on SAFIRE.

Benford, Dominic J.↗
NASA NTRS2008

A New Technique for Retrieval of Tropospheric and Stratospheric Ozone Profiles using Sky Radiance Measurements at Multiple View Angles: Application to a Brewer Spectrometer

This paper describes and applies a new technique for retrieving diurnal variability in tropospheric ozone vertical distribution using ground-based measurements of ultraviolet sky radiances. The measured radiances are obtained by a polarization-insensitive modified Brewer double spectrometer located at Goddard Space Flight Center, in Greenbelt, Maryland, USA. Results demonstrate that the Brewer angular (0-72deg viewing zenith angle) and spectral (303-320 nm) measurements of sky radiance in the solar principal plane provide sufficient information to derive tropospheric ozone diurnal variability. In addition, the Brewer measurements provide stratospheric ozone vertical distributions at least twice per day near sunrise and sunset. Frequent measurements of total column ozone amounts from direct-sun observations are used as constraints in the retrieval. The vertical ozone profile resolution is shown in terms of averaging kernels to yield at least four points in the troposphere-low stratosphere, including good information in Umkehr layer 0 (0-5 km). The focus of this paper is on the derivation of stratospheric and tropospheric ozone profiles using both simulated and measured radiances. We briefly discuss the necessary modifications of the Brewer spectrometer that were used to eliminate instrumental polarization sensitivity so that accurate sky radiances can be obtained in the presence of strong Rayleigh scattering and aerosols. The results demonstrate that including a site-specific and time-dependent aerosol correction, based on Brewer direct-sun observations of aerosol optical thickness, is critical to minimize the sky radiance residuals as a function of observing angle in the optimal estimation inversion algorithm and improve the accuracy of the retrieved ozone profile.

Tzortziou, Maria↗