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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

Status of 2 micron laser technology program

The status of 2 micron lasers for windshear detection is described in viewgraph form Theoretical atmospheric and instrument system studies have demonstrated that the 2.1 micron Ho:YAG lasers can effectively measure wind speeds in both wet and dry conditions with accuracies of 1 m/sec. Two micron laser technology looks very promising in the near future, but several technical questions remain. The Ho:YAG laser would be small, compact, and efficient, requiring little or no maintenance. Since the Ho:YAG laser is laser diode pumped and has no moving part, the lifetime of this laser would be directly related to the diode laser lifetimes which can perform in excess of 10,000 hours. Efficiencies of 3 to 12 percent are expected, but laser demonstrations confirming the ability to Q-switch this laser are required. Coherent laser operation has been demonstrated for both the CW and Q-switched lasers.

Storm, Mark↗
NASA NTRS2005

Orbit Modification of Earth-Crossing Asteroids/Comets Using Rendezvous Spacecraft and Laser Ablation

This report describes the approach and results of an end-to-end simulation to deflect a long-period comet (LPC) by using a rapid rendezvous spacecraft and laser ablation system. The laser energy required for providing sufficient deflection DELTA V and an analysis of possible intercept/rendezvous spacecraft trajectories are studied in this analysis. These problems minimize a weighted sum of the flight time and required propellant by using an advanced propulsion system. The optimal thrust-vector history and propellant mass to use are found in order to transfer a spacecraft from the Earth to a targeted celestial object. One goal of this analysis is to formulate an optimization problem for intercept/rendezvous spacecraft trajectories. One approach to alter the trajectory of the object in a highly controlled manner is to use pulsed laser ablative propulsion. A sufficiently intense laser pulse ablates the surface of a near-Earth object (NEO) by causing plasma blowoff. The momentum change from a single laser pulse is very small. However, the cumulative effect is very effective because the laser can interact with the object over long periods of time. The laser ablation technique can overcome the mass penalties associated with other nondisruptive approaches because no propellant is required to generate the DELTA V (the material of the celestial object is the propellant source). Additionally, laser ablation is effective against a wide range of surface materials and does not require any landing or physical attachment to the object. For diverting distant asteroids and comets, the power and optical requirements of a laser ablation system on or near the Earth may be too extreme to contemplate in the next few decades. A hybrid solution would be for a spacecraft to carry a laser as a payload to a particular celestial body. The spacecraft would require an advanced propulsion system capable of rapid rendezvous with the object and an extremely powerful electrical generator, which is likely needed for the propulsion system as well. The spacecraft would station-keep with the object at a small standoff distance while the laser ablation is performed.

Park, Sang-Young↗
DOE OSTI2021

Cell-Type-Specific Proteomics Analysis of a Small Number of Plant Cells by Integrating Laser Capture Microdissection with a Nanodroplet Sample Processing Platform

Plant organs and tissues contain multiple cell types, which are well organized in 3-dimensional structure to efficiently perform physiological functions such as homeostasis, response to environmental perturbation, pathogen infection. It is critically important to perform molecular measurements at the cell-type-specific level to discover mechanisms and unique features of cell populations that govern differentiation and respond to external perturbations. Although mass spectrometry-based proteomics has been demonstrated as an enabling discovery tool to study plant physiology, conventional approaches require millions of cells to generate robust biological conclusions. Such requirements mask the cell-to-cell heterogeneities and limit the comprehensive profiling of plant proteins at spatially resolved and cell-type-specific resolutions. This protocol describes a recently-developed proteomics workflow for studying a small number of plant cells by integrating laser capture microdissection, microfluidic nanodroplet-based sample preparation, with ultrasensitive liquid chromatography-mass spectrometry. Using poplar as a model tree species, we provide detailed protocols, including plant tissue harvest, tissue preparation, cryosectioning, laser microdissection, protein digestion, mass spectrometry measurement, and data analysis. We show the workflow enables the precise identification and quantification of thousands of proteins from hundreds of isolated plant root and leaf cells.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1981

Small-angle approximation to the transfer of narrow laser beams in anisotropic scattering media

The broadening and the signal power detected of a laser beam traversing an anisotropic scattering medium were examined using the small-angle approximation to the radiative transfer equation in which photons suffering large-angle deflections are neglected. To obtain tractable answers, simple Gaussian and non-Gaussian functions for the scattering phase functions are assumed. Two other approximate approaches employed in the field to further simplify the small-angle approximation solutions are described, and the results obtained by one of them are compared with those obtained using small-angle approximation. An exact method for obtaining the contribution of each higher order scattering to the radiance field is examined but no results are presented.

Box, M. A.↗
NASA NTRS1972

Alignment microscope for rotating laser scanner

Microscopic assembly for alignment of rotary laser focuses on small film area along scan line at oblique angle. Suitable choice of angle and location of optical components project laser beam line as X coordinate reticle. Coordination with horizontal recticle line included microscope facilitates Y coordinate position indexing.

Maciel, A., Jr.↗
NASA NTRS1988

Multiple-Diode-Laser Gas-Detection Spectrometer

Small concentrations of selected gases measured automatically. Proposed multiple-laser-diode spectrometer part of system for measuring automatically concentrations of selected gases at part-per-billion level. Array of laser/photodetector pairs measure infrared absorption spectrum of atmosphere along probing laser beams. Adaptable to terrestrial uses as monitoring pollution or control of industrial processes.

Webster, Christopher R.↗
NASA NTRS1989

Analysis of Nd3+:glass, solar-pumped, high-powr laser systems

The operating characteristics of Nd(3+):glass lasers energized by a solar concentrator were analyzed for the hosts YAG, silicate glass, and phosphate glass. The modeling is based on the slab zigzag laser geometry and assumes that chemical hardening methods for glass are successful in increasing glass hardness by a factor of 4. On this basis, it was found that a realistic 1-MW solar-pumped laser might be constructed from phosphate glass 4 sq m in area and 2 mm thick. If YAG were the host medium, a 1-MW solar-pumped laser need only be 0.5 sq m in area and 0.5 cm thick, which is already possible. In addition, Nd(3+) doped glass fibers were found to be excellent solar-pumped laser candidates. The small diameter of fibers eliminates thermal stress problems, and if their diameter is kept small (10 microns), they propagate a Gaussian single mode which can be expanded and transmitted long distances in space. Fiber lasers could then be used for communications in space or could be bundled and the individual beams summed or phase-matched for high-power operation.

Zapata, L. E.↗
NASA NTRS1999

Interchange for Joint Research Entitled: Miniature Laser Spectrometer for Stable Isotope Measurements

As a first step in successfully measuring carbon isotopes optically we have previously demonstrated the measurement of C-13/C-12 to a precision of 0.1% using a tunable diode laser and CO2 spectral lines in the 2300/cm spectral region. This precision of 0.1% (1 per mil) for carbon isotopes is a value sufficiently precise to provide important isotopic data of interest to astrobiologists. The precision presently attainable in gases is sufficient to permit our instrument to be used in the measurement of isotopic ratios of interest to astrobiologists as well as geologists and planetary scientists. A small stable isotope laser spectrometer with a 10 cm path gas cell was designed and constructed. The cell was integrated with a liquid nitrogen cooled tunable diode laser and indium antimonide detector for evaluation. Using the small gas cell, preliminary measurements of 13C/12C in CO2 were made employing single-beam sequential acquisitions of the required spectral data. The results indicate an accuracy of 0.1% which is sufficiently high to make meaningful measurements of martian samples. In addition, improvements in the spectrometer gas handling system have been made to markedly reduce C-13/C-12 isotopic fractionation during sample gas cell loading which we expect will lead to further improvements in precision and accuracy. An important part of making isotopic ratio measurements in solid samples using diode lasers is the conversion of the elements of interest to molecules that have absorption spectra in the mid-ir spectral range accessible by tunable diode lasers. In this project we have investigated the necessary sample preparation procedures to extract carbon, an element of astrobiological importance, from model soil compounds and to convert it to CO2, a molecule with appropriate optical absorption characteristics for reliable laser spectrometer isotopic ratio measurements of 13C/12C. We have considered calcium carbonate as a model for a component of the martian regolith, and we have formulated a simple heating protocol for extracting carbon in the form of CO2.

Becker, J. F.↗
NASA NTRS1973

Cautionary note concerning the CuSO4 X-ray laser

For the so far unconfirmed lasing action claimed by Kepros et al. (1972) to have been obtained by focusing a 1.06-micron radiation of a q-switched Nd(3+) glass laser to a small cylindrical volume inside a CuSO4-doped gelatin medium supported between two glass plates, an alternate explanation is proposed that does not depend on the assumption of laser action in copper. The proposed explanation shows how collimated X-ray beams might be created under the experimental conditions described by Kepros et al.

Billman, K. W.↗
NASA NTRS1991

Platinum/Tin Oxide/Silica Gel Catalyst Oxidizes CO

Heterogeneous catalyst of platinum, tin oxide, and silica gel combines small concentrations of laser dissociation products, CO and O2, to form CO22 during long times at ambient temperature. Developed as means to prevent accumulation of these products in sealed CO2 lasers. Effective at ambient operating temperatures and installs directly in laser envelope. Formulated to have very high surface area and to chemisorb controlled quantities of moisture: chemisorbed water contained within and upon its structure, makes it highly active and very longlived so only small quantity needed for long times.

Upchurch, Billy T.↗
NASA NTRS1973

The waveguide CO2 laser

A waveguide carbon dioxide laser is reported that is characterized by a very narrow capillary which contains the laser mix. The small capillary allows the device to be operated at pressures as high as 500 torr; pressure broadening of the molecular line is used for tuning. The capillary is placed between two reflectors which provide feedback for the laser oscillation.

Degnan, J. J., III↗
NASA NTRS1978

A new concept for solar pumped lasers

A new approach is proposed in which an intermediate body heated by sunlight is used as the pumping source for IR systems, i.e., concentration solar radiation is absorbed and reradiated via an intermediate blackbody. This body is heated by focused sunlight to a high temperature and its heat losses are engineered to be small. The cooled laser tube (or tubes) is placed within the cavity and is pumped by it. The advantage is that the radiation spectrum is like a blackbody at the intermediate temperature and the laser medium selectively absorbs this light. Focusing requirements, heat losses, and absorption bandwidths of laser media are examined, along with energy balance and potential efficiency. The results indicate that for lasers pumped through an IR absorption spectrum, the use of an intermediate blackbody offers substantial and important advantages. The loss in radiative intensity for optical pumping by a lower-temperature body is partly compensated by the increased solid angle of exposure to the radiative environment.

Christiansen, W. H.↗
NASA NTRSDate not supplied

Variability in Mt. Sharp Group Bedrock as Seen By ChemCam Passive and Active Spectra

The Curiosity rover landed in Gale crater in August 2012 and has since been travelling up the central sedimentary mound known as Mt. Sharp. The ChemCam instrument on Curiosity was designed primarily for the use of Laser Induced Breakdown Spectroscopy (LIBS), where a laser ablates a small amount of material from the target and the spectrum of the resulting plasma yields elemental abundance data. ChemCam’s three spectrometers range from 240-905 nm and can also take passive spectra (without the use of the laser). The spectral range ChemCam passive spectra observe is sensitive to charge-transfer and crystal field absorptions related to iron-bearing minerals. In the first 2934 sols of Curiosity’s mission, 9,400 passive spectra were taken of bedrock targets in Mt. Sharp’s Murray and Carolyn Shoemaker formations. We examine these spectra using spectral slope/ratio and band depth calculations as well as Principal Component Analysis (PCA). For the first time, paired passive spectra and LIBS elemental abundances are compared on a large scale. Finally, CheMin data are compared to ChemCam passive observations to understand sources of spectral variability.

H T Manelski↗
NASA NTRSDate not supplied

Particle Seeding Method for Small-Scale, High-Pressure Nozzles

NASA tests new launch and reentry vehicle configurations in wind tunnels, where flow visualizations and quantitative flowfield measurements are often desired. Some of these vehicles have rocket motors for propulsion, retro-propulsion, or reaction control. High-pressure air is used to supply these rocket motor plumes. However, it is difficult to make off-body measurements in these regions, for several reasons. First, the plumes themselves lack seeding particles for flow diagnostics, and at the low pressures after expansion, Rayleigh scattering or other molecular techniques yield insufficient signal for flow velocity measurements. Second, the plumes displace particle-seeded tunnel air, preventing measurements in the vicinity of the plume. Third, the plumes force shock waves ahead of the vehicle, which melts the ice crystal fog commonly used for visualization and measurement techniques in certain facilities. In the current work, a novel method for seeding the flow in these small-scale, high-pressure nozzles has been devised and initially demonstrated, potentially enabling quantitative and qualitative measurements with particle-based instruments such as Doppler global velocimetry or particle image velocimetry. The method involves a Venturi contraction to draw the seed liquid out of a reservoir and into the nozzle channel, wherein shearing forces atomize the seed into particles. The concept was tested with a laser sheet visualization, which demonstrated that the flow rate of liquid spray was controllable; a valve could be adjusted to drop the flow rate by up to 65%. This relatively inexpensive and simple technique may prove useful in wind tunnel experiments involving particle-based laser diagnostics and small, high-pressure nozzles.

lasers↗
NASA NTRS2001

Laser Ignition Technology for Bi-Propellant Rocket Engine Applications

The fiber optically coupled laser ignition approach summarized is under consideration for use in igniting bi-propellant rocket thrust chambers. This laser ignition approach is based on a novel dual pulse format capable of effectively increasing laser generated plasma life times up to 1000 % over conventional laser ignition methods. In the dual-pulse format tinder consideration here an initial laser pulse is used to generate a small plasma kernel. A second laser pulse that effectively irradiates the plasma kernel follows this pulse. Energy transfer into the kernel is much more efficient because of its absorption characteristics thereby allowing the kernel to develop into a much more effective ignition source for subsequent combustion processes. In this research effort both single and dual-pulse formats were evaluated in a small testbed rocket thrust chamber. The rocket chamber was designed to evaluate several bipropellant combinations. Optical access to the chamber was provided through small sapphire windows. Test results from gaseous oxygen (GOx) and RP-1 propellants are presented here. Several variables were evaluated during the test program, including spark location, pulse timing, and relative pulse energy. These variables were evaluated in an effort to identify the conditions in which laser ignition of bi-propellants is feasible. Preliminary results and analysis indicate that this laser ignition approach may provide superior ignition performance relative to squib and torch igniters, while simultaneously eliminating some of the logistical issues associated with these systems. Further research focused on enhancing the system robustness, multiplexing, and window durability/cleaning and fiber optic enhancements is in progress.

Thomas, Matthew E.↗
NASA NTRS1978

A review of the thermoelectronic laser energy converter (TELEC) program at Lewis Research Center

The investigation of the Thermoelectronic Laser Energy Converter (TELEC) concept began with a feasibility study of a 1 megawatt sized TELEC system. The TELEC was to use either cesium vapor or hydrogen as the plasma medium. The cesium vapor TELEC appears to be the more practical device studied with an overall calculated conversion efficiency of greater than 48%. Following this study, a small TELEC cell was fabricated which demonstrated the conversion of a small amount of laser power to electrical power. The cell developed a short circuit current of 0.7 amperes and an open circuit voltage, as extrapolated from volt-ampere curves, of about 1.5 volts.

Alger, D. L.↗
NASA NTRS1978

A review of the Thermoelectronic Laser Energy Converter /TELEC/ Program at Lewis Research Center

The investigation of the Thermoelectronic Laser Energy Converter (TELEC) concept at the Lewis Research Center (LeRC) began with a feasibility study of a 1 megawatt sized TELEC system. The TELEC was to use either cesium vapor or hydrogen as the plasma medium. The cesium vapor TELEC appears to be the more practical device studied with an overall calculated conversion efficiency of greater than 48%. Following this study, a small TELEC cell was fabricated which demonstrated the conversion of a small amount of laser power to electrical power. The cell developed a short circuit current of 0.7 amperes and an open circuit voltage, as extrapolated from volt-ampere curves, of about 1.5 volts. Work is now in progress to construct and test a cesium vapor TELEC capable of absorbing 20% of an incident 10 kW, 10.6 micrometer beam, and converting 35% of this power to electrical power.

Alger, D. L.↗
NASA NTRSDate not supplied

Particle Seeding Method for Small-Scale, High-Pressure Nozzles

NASA tests new launch and reentry vehicle configurations in wind tunnels, where flow visualizations and quantitative flowfield measurements are often desired. Some of these vehicles have rocket motors for propulsion, retro-propulsion, or reaction control. High-pressure air is used to supply these rocket motor plumes. However, it is difficult to make off-body measurements in these regions, for several reasons. First, the plumes themselves lack seeding particles for flow diagnostics, and at the low pressures after expansion, Rayleigh scattering or other molecular techniques yield insufficient signal for flow velocity measurements. Second, the plumes displace particle-seeded tunnel air, preventing measurements in the vicinity of the plume. Third, the plumes force shock waves ahead of the vehicle, which melts the ice crystal fog commonly used for visualization and measurement techniques in certain facilities. In the current work, a novel method for seeding the flow in these small-scale, high-pressure nozzles has been devised and initially demonstrated, potentially enabling quantitative and qualitative measurements with particle-based instruments such as Doppler global velocimetry or particle image velocimetry. The method involves a Venturi contraction to draw the seed liquid out of a reservoir and into the nozzle channel, wherein shearing forces atomize the seed into particles. The concept was tested with a laser sheet visualization, which demonstrated that the flow rate of liquid spray was controllable; a valve could be adjusted to drop the flow rate by up to 65%. This relatively inexpensive and simple technique may prove useful in wind tunnel experiments involving particle-based laser diagnostics and small, high-pressure nozzles.

Aditya S. Acharya↗