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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1988

The radial velocity search for extrasolar planets

Researchers are measuring small changes in the line-of-sight velocities of stars to detect the oscillating reflex acceleration induced by large planets. The intention is to observe enough stars for a long enough time to be able to make a statement of the probability of planets in a certain range of masses even if no planetary perturbations are detected. To make these measurements of Doppler shift with the required sensitivity, a new instrument was specifically designed, built and tested for this campaign of ground-based planet detection. The instrument is an optical spectrometer for which wavelengths are first calibrated by transmission through a tunable Fabry-Perot etalon interferometer. The intrinsic stability of the etalon and an image-scrambling fiber optic light feed provide great sensitivity to line-of-sight accelerations and immunity to systematic errors.

Mcmillen, Robert S.↗
NASA NTRS2018

Imaging Technique for High Precision Measurement of Detector Stability for the Ocean Color Instrument

One of the new projects by NASA to explore environmental change is the Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) spacecraft. The primary instrument aboard the PACE spacecraft is the Ocean Color Instrument (OCI), an advanced optical spectrometer that will measure the color of the ocean from the ultraviolet to shortwave infrared range for the purpose of observing and monitoring ocean and coastal biology. As part of the optical alignment testing that must be completed before the instrument is built, the measurement stability of the detectors at space flight operating temperatures must be determined to ensure alignment is maintained. Therefore, this project focuses on the development of an imaging technique that adheres to testing requirements and can be used to determine the stability of the OCI detector. The movements of targets affixed to a high-precision stage were analyzed through an image processing program to test the ability of the imaging technique to detect very small (under 10 micrometers) movements. It was found that movements as small as half a pixel (~6 microns) and 1 pixel (~12 microns) were able to be accurately and consistently detected with this imaging technique. This project found that the designed image analysis technique fulfills testing and measurement requirements and will be an effective metrology technique for the OCI detector stability test.

Optics↗
NASA NTRS2018

Tandem LA-ICP-MS & LIBS; A New Micro-Analytical Technique for the Measurement of Every Element in the Periodic Table

Laser Ablation ICP-MS (LA-ICP-MS) has been widely accepted as a microanalytical technique for in-situ trace (ppb) elemental analysis on the micron scale in a variety of geologic materials. LA-ICP-MS (single or multi-collector) provides both elemental and isotopic measurements critical for a wide range of geological research by generating a fine grained aerosol (nm scale) during the laser ablation event and delivering that aerosol to the ICP ion source of the mass spectrometer via an inert carrier gas. LA-ICP-MS, however, suffers from limitations in analyzing high ionization potential elements as well as elements subject to atmospheric and argon based interferences. LA-ICP-MS also has limitations in analyzing major elements due to detector saturation. An alternative laser ablation technique, Laser Induced Breakdown Spectroscopy (LIBS), employs an optical spectrometer integrated into the laser ablation system that analyzes the laser induced plasma at the sample surface across the entire optical spectrum for emission lines of every element in the periodic table. Elements that are difficult or impossible to measure with LA-ICP-MS are now possible to analyze with LIBS down to low ppm levels with CCD and/or ICCD detection. We introduce a new laser based technique, “Tandem LA-LIBS”, that combines LA for ICP-MS and LIBS into one integrated laser ablation system. This system has the effect of expanding the elemental coverage and the dynamic range of the laser ablation experiment as measurements from ppb to % level matrix elements can now be analyzed in a single ablation experiment. We present both femtosecond and nanosecond Tandem LA-LIBS quantitative and qualitative data on wide range of geological materials for those elements that are difficult or impossible by traditional LA-ICP-MS techniques such as F, H, O, N, C, S, halogens, etc. We also demonstrate that the simultaneous measurement of trace, minor and major elements are now possible in a single laser ablation experiment with Tandem LA-LIBS technology.

LA-ICP-MS↗
NASA NTRS2008

NASA Tech Briefs, February 2008

Topics discussed include: Optical Measurement of Mass Flow of a Two-Phase Fluid; Selectable-Tip Corrosion-Testing Electrochemical Cell; Piezoelectric Bolt Breakers and Bolt Fatigue Testers; Improved Measurement of B(sub 22) of Macromolecules in a Flow Cell; Measurements by a Vector Network Analyzer at 325 to 508 GHz; Using Light to Treat Mucositis and Help Wounds Heal; Increasing Discharge Capacities of Li-(CF)(sub n) Cells; Dot-in-Well Quantum-Dot Infrared Photodetectors; Integrated Microbatteries for Implantable Medical Devices; Oxidation Behavior of Carbon Fiber-Reinforced Composites; GIDEP Batching Tool; Generic Spacecraft Model for Real-Time Simulation; Parallel-Processing Software for Creating Mosaic Images; Software for Verifying Image-Correlation Tie Points; Flexcam Image Capture Viewing and Spot Tracking; Low-Pt-Content Anode Catalyst for Direct Methanol Fuel Cells; Graphite/Cyanate Ester Face Sheets for Adaptive Optics; Atomized BaF2-CaF7 for Better-Flowing Plasma-Spray Feedstock; Nanophase Nickel-Zirconium Alloys for Fuel Cells; Vacuum Packaging of MEMS With Multiple Internal Seal Rings; Compact Two-Dimensional Spectrometer Optics; and Fault-Tolerant Coding for State Machines.

Source record↗
NASA NTRS1979

DUMAND Summer Workshop, University of California, La Jolla, Calif., July 24-September 2, 1978, Proceedings. Volume 1 - Array studies

Papers are presented concerning the design and implementation of the optical and acoustic sensors that will comprise the DUMAND (Deep Underwater Muon and Neutrino Detector) array. Specific topics include the results of experiments on atmospheric muon and neutrino spectra obtained with various muon and neutrino spectrometers, optical sensors and arrays, optical data handling systems, the simulation of the sound generated by high-energy particles in water, constraints on acoustic arrays, standard ocean parameters for DUMAND calculations, and Monte Carlo investigations of hadronic and electromagnetic cascades in sea water.

Roberts, A.↗
NASA NTRS1986

The radial velocity search for extrasolar planets

Stars are observed with a ground-based instrument designed to measure small changes in the line-of-sight velocities. The purpose of the observations is to detect large planets by the oscillatory reflex motion they induce on the stars they are orbiting. The instrument is an optical spectrometer for which wavelengths are first calibrated by transmission through a tunable Fabry-Perot etalon interferometer. Changes in the line-of-sight velocities are revealed by changes in the Doppler shift of the absorption-line spectra of stars. The scrambling of incident light by an optical fiber and the stability of wavelength calibration by a tilt-tunable Fabry-Perot etalon provide immunity to systematic errors that historically have effected more conventional radial velocity spectrographs. A cross-dispersed echelle spectrograph spatially separates the orders of constructive interference transmitted through the etalon. Selecting several echelle diffraction orders in the vicinity of 4250 to 4750 A, which are imaged on a CCD, about 350 points on the profile of the stellar spectrum are sampled by successive orders of interferometric transmission through the etalon.

Mcmillen, R. S.↗
NASA NTRS2013

Electro-Optic Time-to-Space Converter for Optical Detector Jitter Mitigation

A common problem in optical detection is determining the arrival time of a weak optical pulse that may comprise only one to a few photons. Currently, this problem is solved by using a photodetector to convert the optical signal to an electronic signal. The timing of the electrical signal is used to infer the timing of the optical pulse, but error is introduced by random delay between the absorption of the optical pulse and the creation of the electrical one. To eliminate this error, a time-to-space converter separates a sequence of optical pulses and sends them to different photodetectors, depending on their arrival time. The random delay, called jitter, is at least 20 picoseconds for the best detectors capable of detecting the weakest optical pulses, a single photon, and can be as great as 500 picoseconds. This limits the resolution with which the timing of the optical pulse can be measured. The time-to-space converter overcomes this limitation. Generally, the time-to-space converter imparts a time-dependent momentum shift to the incoming optical pulses, followed by an optical system that separates photons of different momenta. As an example, an electro-optic phase modulator can be used to apply longitudinal momentum changes (frequency changes) that vary in time, followed by an optical spectrometer (such as a diffraction grating), which separates photons with different momenta into different paths and directs them to impinge upon an array of photodetectors. The pulse arrival time is then inferred by measuring which photodetector receives the pulse. The use of a time-to-space converter mitigates detector jitter and improves the resolution with which the timing of an optical pulse is determined. Also, the application of the converter enables the demodulation of a pulse position modulated signal (PPM) at higher bandwidths than using previous photodetector technology. This allows the creation of a receiver for a communication system with high bandwidth and high bits/photon efficiency.

Birnbaum, Kevin↗
NASA NTRSDate not supplied

Micro-Spectrometer for Resource Mapping in Extreme Environments

Measurements and analyses of resources within permanently shadowed craters and along steep embankments on extraterrestrial surfaces pose extreme challenges since astronauts and rovers cannot access them. However, these areas offer the potential for the greatest scientific returns. Researchers at the NASA Langley Research Center (LaRC) invented a deployable wireless micro-spectrometer that can access those challenging areas and deliver telemetry data to a receiver safely outside those extreme environments. The micro-spectrometers are designed for deployment by an astronaut, a rover, or a lander flying overhead. This device can also be installed on rover tires, under the astronaut’s shoes, or on a cane stick. The bullet-like, expendable micro-spectrometer can penetrate into soil to spectrally identify the components of soil, such as water, He-3, or other minerals. The signals from the soil assay data are transmitted to a mother station through a telemetry system. This LaRC developed micro-spectrometer bullet consists of micro-spectrometer optics with an all-imbedded, burst-mode, light-emitting-diode ultraviolet (LED UV) light source, a super-capacitor with control electronics, and telemetry electronics. Prototypes have been fabricated to demonstrate a spectral assay of soil components. Further maturation of this technology would be necessary for demonstrations on the Moon.

micro-spectrometer↗
NASA NTRS1990

Thermal Infrared Imaging Spectrometer - An advanced optics technology instrument

Through the use of a special optical filter, the Thermal Infrared Imaging Spectrometer, an airborne multispectral IR imaging instrument operating in the thermal emission region (7.5-14 microns), will achieve signal-to-noise ratios greater than 600 with ambient temperature optics. This instrument will be used to do compositional surface mapping of the terrain, and will refine the ability to categorize rock families and types by providing much higher spectral resolution in the emission region than was previously available. Details of the optical system, the detector, the cooler system, and the support electronics are described.

Mahoney, Colin↗
NASA NTRSDate not supplied

Low Cost Micro-Spectrometer for Resource Mapping on Mars

Scientific measurements within craters and along steep embankments on Mars pose extreme challenges since astronauts and rovers cannot access them. However, these areas offer the potential for thegreatest scientific return. NASA Langley Research Center (LaRC) has invented a deployable wireless micro-spectrometer [1-13] capable of accessing thosechallenging areas and, using telemetry, send measurements to a receiver safely outside those extreme environments. A prototype of the micro-spectrometer concept was fabricated and successfullytested for measurement of dopamine as a neural probe [14]. The bullet-sized micro-spectrometer concept can be designed for deployment by an astronaut, a rover, an aerial drone, or a lander, and the measurements broadcasted back to a receiver [13,15,16]. This device can also be installed on rovertires, under the astronaut’s boots, or a cane stick. The bullet-like consumable micro-spectrometer can penetrate soil to spectrally identify the components ofthe soil, such as water or minerals. The signals of the soil assay data are transmitted to a mother station through a telemetry system. The LaRC developed micro-spectrometer bullet consists of micro-spectrometer optics with an all imbedded burst-mode LED UV light source, a super-capacitor with control electronics, and telemetry electronics. Prototypes have been fabricated to demonstrate spectral assay of soil components. Further maturation of this technology would be necessary for demonstration on Mars. Future work includes a potential R&D program that includes other NASA Centers and industry partners interested in developing a business case that requires knowledge of the locations of extraterrestrial ice, for instance.

micro-spectrometer, mineral assay, resource mappin↗
NASA NTRSDate not supplied

Hydrogen Sensor via Plasma Techniques Development

Currently, NASA Kennedy Space Center’s Exploration Ground Systems (EGS) uses liquid hydrogen (LH 2 ) as fuel for launches and ensures hydrogen is no longer in the fill lines by sampling gas into a controlled environment. Then they use a catalytic sensor that detects when hydrogen interacts with oxygen. However, this procedure requires repeatedly backfilling and flushing with helium, which can be wasteful during a global helium shortage and expensive for each sampling port. Therefore, the team at KSC set out to establish proof-of-concept of a plasma-based hydrogen sensor that is anaerobic – and can in fact detect in most environments and below atmospheric pressures – and with a small footprint and more sensitive than other hydrogen sensors currently on the market. The technology development was done by testing known concentrations of hydrogen in argon gas fed through a vacuum cube containing an electrode feedthrough at varying pressures. The resultant emission spectra were recorded with a fiber optic spectrometer and analyzed to determine the instrument's accuracy. Throughout testing, efforts were made to prove the off-the-shelf capabilities of the setup. The traditional high voltage AC-power source was switched to an affordable, handheld plasma lighter. Additionally, the spectrometer was supplemented with a double photodiode circuit to take targeted measurements of the Balmer-α and - β lines in the hydrogen spectrum. From this, we established a proof of concept sensor. SLS required it to detect as low as 100 ppm whereas we detected hydrogen in concentrations as low as 50 ppm and in an anaerobic environment. * Work supported by NASA Kennedy Space Center’s Science Mission Directorate Innovative Research and Development Fund.

Plasma↗
NASA NTRS2012

The Cabauw Intercomparison Campaign for Nitrogen Dioxide Measuring Instruments (CINDI): Design, Execution, and Early Results

From June to July 2009 more than thirty different in-situ and remote sensing instruments from all over the world participated in the Cabauw Intercomparison campaign for Nitrogen Dioxide measuring Instruments (CINDI). The campaign took place at KNMI's Cabauw Experimental Site for Atmospheric Research (CESAR) in the Netherlands. Its main objectives were to determine the accuracy of state-ofthe- art ground-based measurement techniques for the detection of atmospheric nitrogen dioxide (both in-situ and remote sensing), and to investigate their usability in satellite data validation. The expected outcomes are recommendations regarding the operation and calibration of such instruments, retrieval settings, and observation strategies for the use in ground-based networks for air quality monitoring and satellite data validation. Twenty-four optical spectrometers participated in the campaign, of which twenty-one had the capability to scan different elevation angles consecutively, the so-called Multi-axis DOAS systems, thereby collecting vertical profile information, in particular for nitrogen dioxide and aerosol. Various in-situ samplers and lidar instruments simultaneously characterized the variability of atmospheric trace gases and the physical properties of aerosol particles. A large data set of continuous measurements of these atmospheric constituents has been collected under various meteorological conditions and air pollution levels. Together with the permanent measurement capability at the CESAR site characterizing the meteorological state of the atmosphere, the CINDI campaign provided a comprehensive observational data set of atmospheric constituents in a highly polluted region of the world during summertime. First detailed comparisons performed with the CINDI data show that slant column measurements of NO2, O4 and HCHO with MAX-DOAS agree within 5 to 15%, vertical profiles of NO2 derived from several independent instruments agree within 25% of one another, and MAX-DOAS aerosol optical thickness agrees within 20-30% with AERONET data. For the in-situ NO2 instrument using a molybdenum converter, a bias was found as large as 5 ppbv during day time, when compared to the other in-situ instruments using photolytic converters.

Atmospheric composition↗
NASA NTRS1972

Flame spectra of solid propellants during unstable combustion.

The spectral and temporal details of the flames of a series of ammonium perchlorate-polyurethane propellants during both unstable and stable combustion were observed experimentally. A 400-scan per second optical spectrometer operating in the middle infrared region was used. During unstable combustion at low ratios of chamber free volume to nozzle throat area, three different frequencies were observed simultaneously. These were attributable to at least two mechanisms. During stable combustion periodic fluctuations in flame temperature and composition were also observed. Some aspects of theory of bulk mode instability were confirmed, but the assumptions of constant flame temperature and constant composition were found to be inaccurate.

Eisel, J. L.↗
NASA NTRS1974

Electric Field Induced Spectra of H sub 2 and D sub 2

The frequencies of four Q-branch lines of H2 and five Q-branch lines of D2 were measured as a function of density, and their shifts were observed to be in the linear region. The individual slopes and extrapolated zero density frequency of each line was determined. Hydrogen was measured for polarizability using the integrated intensity of the Q1(0) and S1(1), H2 absorption line. A highly automated technique for determining the response function of the spectrometer using digitally recorded data is presented. For the Q1(0) and Q1(1) lines of H2 the halfwidths were measured as a function of electric field intensity at constant pressure, and again at several densities and compared to previously measured widths. Technical and operational details of equipment built for this experiment, and for the five-meter Littrow spectrometer used, are described. Modifications of the spectrometer optics to accept the Stark cell are discussed.

Boyd, William Joseph↗
NASA NTRS1974

An autoranging scanning system and compatible methods of noise reduction

The autoranging scanning system discussed combines in a unique way four different methods for removing noise. The system employs a narrow-band amplifier. Other noise reduction methods make use of digital summation, convolution numbers, and the coaddition of scans. The system was designed to digitize the output of an infrared spectrometer and to record it on magnetic tape. Light passes through a mechanical light chopper and the spectrometer optics, and falls on the PbS cell to produce a signal which is amplified by the first preamplifier.

Saufley, D. C.↗
NASA NTRS1974

Combustion chemistry of solid propellants

Several studies are described of the chemistry of solid propellant combustion which employed a fast-scanning optical spectrometer. Expanded abstracts are presented for four of the studies which were previously reported. One study of the ignition of composite propellants yielded data which suggested early ammonium perchlorate decomposition and reaction. The results of a study of the spatial distribution of molecular species in flames from uncatalyzed and copper or lead catalyzed double-based propellants support previously published conclusions concerning the site of action of these metal catalysts. A study of the ammonium-perchlorate-polymeric-fuel-binder reaction in thin films, made by use of infrared absorption spectrometry, yielded a characterization of a rapid condensed-phase reaction which is likely important during the ignition transient and the burning process.

Baer, A. D.↗
NASA NTRS1981

Infrared astronomy - Scientific/military thrusts and instrumentation; Proceedings of the Meeting, Washington, DC, April 21, 22, 1981

A series of papers on infrared astronomy is presented. Among the topics discussed are those concerning programs, such as NASA's planning, the Cosmic Background Explorer and a cryogenic infrared radiance instrument for the Space Shuttle. Articles on infrared astronomy technology include those on an infrared camera for 10-micron astronomy, bulk and integrated acousto-optic spectrometers for molecular astronomy with heterodyne spectrometers, and airborne measurements of infrared atmospheric radiance and sky noise. Several papers on infrared astronomy spectroscopy are included, such as infrared heterodyne spectroscopy and infrared lines from shocked galactic gases. Among the articles on infrared astronomy catalogues and operations are discussions of groundbased infrared measurements using the AMOS/MOTIF facility and the prediction of infrared celestial source counts.

Boggess, N. W.↗