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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 757 records · Page 42
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Frontiers in propulsion research: Laser, matter-antimatter, excited helium, energy exchange thermonuclear fusion

Concepts are described that presently appear to have the potential for propulsion applications in the post-1990 era of space technology. The studies are still in progress, and only the current status of investigation is presented. The topics for possible propulsion application are lasers, nuclear fusion, matter-antimatter annihilation, electronically excited helium, energy exchange through the interaction of various fields, laser propagation, and thermonuclear fusion technology.

Papailiou, D. D.↗
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.↗
DOE OSTI2012

Polarisation effects in twin-core fibre: Application for mode locking in a fibre laser

We report the first measurements of the longitudinal power distribution in a twin-core optical fibre at different input light polarisations. Experimental evidence is presented that, because of the difference in birefringence between the cores, the power in them depends on which core the beam is launched into. Experimental data are interpreted in terms of a modified polarisation model for mode coupling in twin-core fibres which takes into account the birefringence of the cores. In addition, we demonstrate for the first time the use of the polarisation properties of a twincore fibre for mode locking in a fibre laser. (optical fibres, lasers and amplifiers. properties and applications)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
NASA NTRS1978

The response of heat-shield materials to intense laser radiation

Experimental results for the response of ATJ graphite, Carbitex 100, and carbon phenolic to intense continuous-wave laser radiation are presented. Both penetration and mass-loss test techniques are used and compared. The results are also compared with a simple ablation theory applicable to laser irradiation. Reasons for the disparity between experiment and theory, and applicability of the results to other heating situations, such as planetary entry, are discussed.

Lundell, J. H.↗
DOE OSTI2018

Electrolytic Plasma Surface Polishing of Complex Components Produced by Selective Laser Melting

The applicability of electrolytic plasma surface polishing to complex components produced by selective laser melting (SLM) is analyzed. By electrolytic plasma polishing by electrolyte spraying, the surface quality of components produced by SLM may be improved. This technology is found to decrease the surface roughness from R{sub a} = 5.6 μm to 1.4 μm. The optimal pressure of the electrolyte jet is 0.02–0.05 MPa. At high pressures, the process becomes unstable. By electrolytic plasma polishing on the basis of electrolyte jets, uniform external and internal surface roughness of components produced by SLM may be ensured.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1997

Light-Directed Ranging System Implementing Single Camera System for Telerobotics Applications

A laser-directed ranging system has utility for use in various fields, such as telerobotics applications and other applications involving physically handicapped individuals. The ranging system includes a single video camera and a directional light source such as a laser mounted on a camera platform, and a remotely positioned operator. In one embodiment, the position of the camera platform is controlled by three servo motors to orient the roll axis, pitch axis and yaw axis of the video cameras, based upon an operator input such as head motion. The laser is offset vertically and horizontally from the camera, and the laser/camera platform is directed by the user to point the laser and the camera toward a target device. The image produced by the video camera is processed to eliminate all background images except for the spot created by the laser. This processing is performed by creating a digital image of the target prior to illumination by the laser, and then eliminating common pixels from the subsequent digital image which includes the laser spot. A reference point is defined at a point in the video frame, which may be located outside of the image area of the camera. The disparity between the digital image of the laser spot and the reference point is calculated for use in a ranging analysis to determine range to the target.

Wells, Dennis L.↗
NASA NTRS1978

Laser power transmission for space power and propulsion

An early status report is presented for a review being made of the state of development of major components and subsystems required for ground-to-space, space-to-space, or space-to-ground laser power transmission for electric or thermal power or propulsion. System characteristics are being evaluated from an applications viewpoint, and major problem areas are being identified. The object is to identify a rewarding first application of lasers for space power and propulsion. An evolution of laser power transmission capabilities over the next 20 years is projected. Supporting technology requirements are to be identified, priorities set, and continued developments coordinated with other government agencies.

Brantley, L. W.↗
DOE OSTI2024

Spatiotemporal control of high-intensity laser pulses with a plasma lens

Spatiotemporal control encompasses a variety of techniques for producing laser pulses with dynamic intensity peaks that move independently of the group velocity. This controlled motion of the intensity peak offers a new approach to optimizing laser-based applications and enhancing signatures of fundamental phenomena. Here, we demonstrate spatiotemporal control with a plasma optic. A chirped laser pulse focused by a plasma lens exhibits a moving focal point, or “flying focus,” that can travel at an arbitrary, predetermined velocity. Unlike currently used conventional or adaptive optics, a plasma lens can be located close to the interaction region and can operate at an orders of magnitude higher, near-relativistic intensity. Published by the American Physical Society 2024

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
NASA NTRS1974

Generation and fluid dynamics of scattering aerosols in laser Doppler velocimetry

An experimental study on the particle-fluid interactions of scattering aerosols was performed using monodisperse aerosols of different particle sizes for the application of laser Doppler velocimeters in subsonic turbulence measurements. Particle response was measured by subjecting the particles to an acoustically excited flow field where the particle Reynolds numbers were controlled to simulate the corresponding values of fluid turbulence. The test aerosols were fairly monodisperse with a mean diameter that could be controlled over the size range from 0.1 to 1.0 micron. Experimental results on the generation of a fairly monodisperse aerosol of solid particles and liquid droplets and on the aerosol response in the frequency range 100 Hz to 100 kHz are presented. The present study indicates that a unit density spherical scatterer of 0.3 micron-diameter would be an optimum choice as tracer particles for subsonic air turbulence measurements.

Mazumder, M. K.↗
NASA NTRS2013

Development of Advanced Seed Laser Modules for Lidar and Spectroscopy Applications

We report on recent progress made in the development of highly compact, single mode, distributed feedback laser (DFB) seed laser modules for lidar and spectroscopy applications from space based platforms. One of the intended application of this technology is in the NASA's Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) mission. The DFB laser modules operating at 1571 nm and 1262 nm have advanced current and temperature drivers built into them. A combination of temperature and current tuning allows coarse and fine adjustment of the diode wavelengths.

Prasad, Narasimha S.↗
NASA NTRS2001

Infrared Fibers for Use in Space-Based Smart Structures

Infrared optical fibers are finding a number of applications including laser surgery, remote sensing, and nuclear radiation resistant links. Utilizing these fibers in space-based structures is another application, which can be exploited. Acoustic and thermal sensing are two areas in which these fibers could be utilized. In particular, fibers could be embedded in IM7/8552 toughened epoxy and incorporated into space structures both external and internal. ZBLAN optical fibers are a candidate, which have been studied extensively over the past 20 years for terrestrial applications. For the past seven years the effects of gravity on the crystallization behavior of ZBLAN optical fiber has been studied. It has been found that ZBLAN crystallization is suppressed in microgravity. This lack of crystallization leads to a fiber with better transmission characteristics than its terrestrial counterpart.

Tucker, Dennis S.↗
NASA NTRS2002

Investigation of Nebular Processes Through Oxygen Isotopic Analysis of Primitive Meteorite Materials

As a direct result of support provided by this grant, precise and accurate determination of delta(18)O and delta(17)O in silicates (and other minerals) by ion microprobe (both IMS 6f and IMS 1270) are now being carried out in several laboratories, and these analyses, combined with application of laser fluorination techniques, have led to a proliferation of oxygen isotopic data in the past approx. 3 years. The applications of these techniques in cosmochemical research have been myriad, from understanding the most refractory objects in the nebula (CAIs) to the low temperature alteration processes on meteorite parent bodies. Here, we describe our progress in understanding the oxygen isotopic microdistributions in primitive meteorite materials, as directly supported by this Origins grant.

Leshin, Laurie↗
NASA NTRS1991

Laser Spectroscopic Measurement Of Temperature And Density

Report discusses research on use of laser-induced fluorescence in oxygen and Raman scattering in air for simultaneous measurement of temperature and density of air. Major application of laser spectroscopic techniques, measurement of fluctuations of temperature and density in hypersonic flows in wind tunnels.

Mckenzie, Robert L.↗
DOE OSTI2024

Laser Powder Bed Fusion of Steels for Nuclear Applications

This report provides an update on laser powder bed fusion of steels for nuclear applications. This report is a Milestone 3 deliverable in FY2024, under work package CT-24AN130401 to support research and qualification activities supported by the Advanced Materials and Manufacturing Technologies (AMMT) program here at Argonne National Laboratory (ANL). Continuing from FY23, the focus of FY24 for ANL includes further optimization of process parameters for three alloys: A709, G91, G92. The work package also includes fabricating test samples to conduct a thorough microstructural analysis and perform preliminary mechanical testing. For the same, we have used CALPHAD-based thermodynamic kinetic modeling to optimize the experimental activities.

36 MATERIALS SCIENCE↗
DOE OSTI2012

Optimization of extreme ultraviolet photons emission and collection in mass-limited laser produced plasmas for lithography application

The progress in development of commercial system for next generation EUV lithography requires, among other factors, significant improvement in EUV photon sources such as discharge produced plasma (DPP) and laser produced plasma (LPP) devices. There are still many uncertainties in determining the optimum device since there are many parameters for the suitable and efficient energy source and target configuration and size. Complex devices with trigger lasers in DPP or with pre-pulsing in LPP provide wide area for optimization in regards to conversion efficiency (CE) and components lifetime. We considered in our analysis a promising LPP source configuration using 10-30 {mu}m tin droplet targets, and predicted conditions for the most efficient EUV radiation output and collection as well as calculating photons source location and size. We optimized several parameters of dual-beam lasers and their relationship to target size. We used our HEIGHTS comprehensive and integrated full 3D simulation package to study and optimize LPP processes with various target sizes to maximize the CE of the system.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
NASA NTRS1973

Spectral line absorption measurement using optical cavities.

A simple technique using a conventional gas laser with spherical mirrors having identical radii of curvature in the nonoscillating regime for spectral line absorption measurements is described and applications for laser work are suggested. The theory of the measurement carried out in the geometrical optical approach for Doppler-broadened lines was checked experimentally and conditions are specified for which measurement inaccuracies of the order of 1% for the peak value of the line absorption coefficient can be obtained. Since the device provides a fine adjustment of the cavity losses, formation of the diffraction modes could be observed in the preoscillating regime of the optical cavity.

Blanaru, D. L.↗