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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 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Laser Shock Modeling Archival Discussion

The purpose of this discussion is to provide archival information related to the Laser Shock finite element modeling effort. As discussed in Laser Shock System, Assessing bond strength in layered materials (see Section 8.0), the Laser Shock System creates a high-amplitude shockwave on the frontside of a structure (i.e. an aluminum 6061-T6 plate for this discussion) via a high-energy pulsed laser. The shock wave is monitored on the back surface of the structure as a velocity time history. It is a compressive wave as it comes to the back surface but reflects as a tensile wave. If a bond exists in the structure and the reflected tensile wave exceeds its interface threshold stress, then bond rupture occurs. The desire of the Laser Shock effort is to establish (with multiple tests) an ultimate bond strength which can be used for fuel plate design calculations. In this process, the finite element modeling effort is the catalyst to mimic the Laser Shock tests and provide the damage information at the bond that is useful for fuel plate design calculations.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
NASA NTRS1983

Closed-loop strain controlled testing at elevated temperatures with a non-contacting gage

Normal strains were measured over a 100 micron gage length at a distance of 50 microns from the edge of a notch using a non-contacting, laser-based interferometric technique. Tests were performed at 600 C under direct strain control from this interferometric 'micro-gage'. A minicomputer system, that produced a voltage analog of strain as a final output, controlled the strain measuring apparatus. This analog output was used directly as the feedback signal to a closed-loop, electrohydraulic mechanical test system. This allowed both strain rate and strain amplitude to be controlled at the notch root of the specimen.

Martin, J. F.↗
NASA NTRS2008

Development and Optical Testing of the Camera, Hand Lens, and Microscope Probe with Scannable Laser Spectroscopy (CHAMP-SLS)

Conducting high resolution field microscopy with coupled laser spectroscopy that can be used to selectively analyze the surface chemistry of individual pixels in a scene is an enabling capability for next generation robotic and manned spaceflight missions, civil, and military applications. In the laboratory, we use a range of imaging and surface preparation tools that provide us with in-focus images, context imaging for identifying features that we want to investigate at high magnification, and surface-optical coupling that allows us to apply optical spectroscopic analysis techniques for analyzing surface chemistry particularly at high magnifications. The camera, hand lens, and microscope probe with scannable laser spectroscopy (CHAMP-SLS) is an imaging/spectroscopy instrument capable of imaging continuously from infinity down to high resolution microscopy (resolution of approx. 1 micron/pixel in a final camera format), the closer CHAMP-SLS is placed to a feature, the higher the resultant magnification. At hand lens to microscopic magnifications, the imaged scene can be selectively interrogated with point spectroscopic techniques such as Raman spectroscopy, microscopic Laser Induced Breakdown Spectroscopy (micro-LIBS), laser ablation mass-spectrometry, Fluorescence spectroscopy, and/or Reflectance spectroscopy. This paper summarizes the optical design, development, and testing of the CHAMP-SLS optics.

Fluorescence↗
NASA NTRS2016

Three Three-Year Aging of Prototype Flight Laser at 10 kHz and 1 ns Pulses With External Frequency Doubler for ICESat-2 Mission

We present the results of three year life-aging of a specially designed prototype flight source laser operating at 1064 nm, 10 kHz, 1ns, 15W average power and external frequency doubler. The Fibertek-designed, slightly pressurized air, enclosed-container source laser operated at 1064 nm in active Q-switching mode. The external frequency doubler was set in a clean room at a normal air pressure. The goal of the experiment was to measure degradation modes at 1064 and 532 nm discreetly. The external frequency doubler consisted of a Lithium triborate, LiB3O5, crystal operated at non-critical phase-matching. Due to 1064 nm diagnostic needs, the amount of fundamental frequency power available for doubling was 13.7W. The power generated at 532 nm was between 8.5W and 10W, depending on the level of stress and degradation. The life-aging consisted of double stress-step operation for doubler crystal, at 0.35 Jcm2 for almost 1 year, corresponding to normal conditions, and then at 0.93 Jcm2 for the rest of the experiment, corresponding to accelerated testing. We observed no degradation at the first step and linear degradation at the second step. The linear degradation at the second stress-step was related to doubler crystal output surface changes and linked to laser-assisted contamination. We discuss degradation model and estimate the expected lifetime for the flight laser at 532 nm. This work was done within the laser testing for NASAs Ice, Cloud, and land Elevation Satellite-2 (ICESat-2) LIDAR at Goddard Space Flight Center in Greenbelt, MD with the goal of 1 trillion shots lifetime.

Lidar↗
NASA NTRS2016

Three Year Aging of Prototype Flight Laser at 10 Khz and 1 Ns Pulses with External Frequency Doubler for the Icesat-2 Mission

We present the results of three year life-aging of a specially designed prototype flight source laser operating at 1064 nm, 10 kHz, 1ns, 15W average power and external frequency doubler. The Fibertek-designed, slightly pressurized air, enclosed-container source laser operated at 1064 nm in active Q-switching mode. The external frequency doubler was set in a clean room at a normal air pressure. The goal of the experiment was to measure degradation modes at 1064 and 532 nm discreetly. The external frequency doubler consisted of a Lithium triborate, LiB3O5, crystal operated at non-critical phase-matching. Due to 1064 nm diagnostic needs, the amount of fundamental frequency power available for doubling was 13.7W. The power generated at 532 nm was between 8.5W and 10W, depending on the level of stress and degradation. The life-aging consisted of double stress-step operation for doubler crystal, at 0.35 J/cm2 for almost 1 year, corresponding to normal conditions, and then at 0.93 J/cm2 for the rest of the experiment, corresponding to accelerated testing. We observed no degradation at the first step and linear degradation at the second step. The linear degradation at the second stress-step was related to doubler crystal output surface changes and linked to laser-assisted contamination. We discuss degradation model and estimate the expected lifetime for the flight laser at 532 nm. This work was done within the laser testing for NASA's Ice, Cloud, and land Elevation Satellite-2 (ICESat-2) LIDAR at Goddard Space Flight Center in Greenbelt, MD with the goal of 1 trillion shots lifetime.

Frequency Doubling↗
NASA NTRS1983

Laboratory simulation of tunable diode laser remote measurement of atmospheric gases using topographic targets

In order to test the possibility that tunable diode laser (TDL) systems using topographic targets can be applied to the measurement of a variety of gases at concentrations and distances characteristic of industrial gas leaks, a single-ended TDL system was assembled for use with selected topographic targets to detect NO2 at atmospheric pressure and NO2 and NH3 at low pressures. In both cases, the intensity distribution of radiation backscattered from selected targets was found to be heavily weighted to a specular rather than a Lambertian distribution. A sensitivity of 5 ppm-m has been demonstrated for the case of NO2.

Webster, C. R.↗
DOE OSTI2025

Microstructure-Based Understanding of High-Temperature Deformation Behaviors in Laser Powder Bed Fusion (LPBF) 316H Stainless Steel

This report presents the results of high-temperature mechanical property testing and microstructural analysis of laser powder bed fusion (LPBF) 316H stainless steel (SS) conducted during Fiscal Year 2025 (FY25) under the U.S. Department of Energy, Office of Nuclear Energy’s Advanced Materials and Manufacturing Technologies (AMMT) program. The study builds upon prior work by expanding the mechanical property test matrix and advancing a microstructure-based mechanistic understanding of LPBF 316H SS performance, with a focus on the solution annealed (SA, 1100°C for 1 hour) materials. High-temperature tension, creep, fatigue, and creep-fatigue tests were performed. Thermal aging studies were conducted. Advanced characterization techniques, including scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), and high-energy synchrotron X-ray diffraction, were employed to investigate the microstructural evolution during thermal aging and mechanical testing. It was discovered that the as-built (AB) LPBF 316H SS exhibited precipitation kinetics during thermal aging that are 10–100 times faster than its wrought counterpart due to the presence of high densities of preferred nucleation sites, while the precipitation kinetics in SA LPBF 316H was under investigation. The accelerated precipitation of embrittling phases such as sigma phase in LPBF 316H SS compared to its wrought counterpart led to significant impacts on creep ductility. The influence of laser printing parameters and build orientations on fatigue and creep-fatigue performance was observed. In assessing the creep-fatigue performance, it was discovered that the SA LPBF 316H samples failed in less than 200 cycles under 595°C, 0.5% (strain amplitude) with a 60-minute hold time. This work establishes a mechanistic framework for predicting the long-term behavior of LPBF 316H SS, supporting its rapid qualification under the ASME BPVC. The findings contribute to the broader goal of enabling the deployment of advanced materials in next-generation nuclear energy systems. An outlook for FY26 work, including continued aging studies, mechanical testing, and microstructural characterization, is provided.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Single particle impact explorations on the role of powder heat treatments in cold spray: Effects of strength and oxide structure

In cold spray, the optimization of the powder feedstock for improving the final properties of the coating and for improving the process itself are two different objectives. This paper explores the latter, studying the relationship between powder pre-heat treatment and the kinetic bonding between the individual particles and the substrate. Using a laser-induced particle impact test (LIPIT), we investigate the effect of different heat treatments on the critical adhesion velocity of Al 6061. Although heat treatments change the strength of the powders as well as the thickness of the native oxide layer each by as much as ∼50 %, the critical adhesion velocity remains constant to within only ∼10 %. A deeper analysis reveals that these two factors change in somewhat complementary ways for the heat treatments explored here, leading to counteracting effects. By quantitatively evaluating these two microstructural factors in tandem, we find that they are roughly equally important in determining the critical adhesion velocity. These observations thus provide insight for the development of new heat treatment regimens that might lower the adhesion velocity.

Al 6061↗
NASA NTRS1988

Diode-pumped laser research

The Laboratory for Oceans is currently working on the development of compact laser diode array (LD) pumped Nd:YAG lasers for use in space-based altimetry and ranging. Laser diode-array pumping technology promises to increase the electrical to optical efficiency of solid state lasers by an order of magnitude with a lifetime increase of nearly three orders of magnitude relative to today's conventional flashlamp-pumped laser systems. The small size, efficiency, and ruggedness make LD-pumped solid state lasers ideal for space based applications. In an in-house RTOP effort, a novel multiple-pass LD-pumped Nd:YAG laser amplifier was designed and tested to increase the 100 microjoule output pulse energy of the Lightwave laser oscillator. Preliminary results have yielded a round trip amplifier gain of about 15 percent using 7 microjoule LD-pump energy. As a parallel activity, funding was recently obtained to investigate the possible use of custom made fiber optic arrays to obtain an efficient optical coupling mechanism between the emitting laser diode-arrays and the target solid state laser material. Fiber optic coupling arrays would allow for the easy manipulation of the spatial emitting pattern of the diode pump sources to match either an end or side pumping laser configuration.

Ramos-Izquierdo, L.↗
NASA NTRS1984

Analysis and testing of a new method for drop size measurement using laser scatter interferometry

Research was conducted on a laser light scatter detection method for measuring the size and velocity of spherical particles. The method is based upon the measurement of the interference fringe pattern produced by spheres passing through the intersection of two laser beams. A theoretical analysis of the method was carried out using the geometrical optics theory. Experimental verification of the theory was obtained by using monodisperse droplet streams. Several optical configurations were tested to identify all of the parametric effects upon the size measurements. Both off-axis forward and backscatter light detection were utilized. Simulated spray environments and fuel spray nozzles were used in the evaluation of the method. The measurements of the monodisperse drops showed complete agreement with the theoretical predictions. The method was demonstrated to be independent of the beam intensity and extinction resulting from the surrounding drops. Signal processing concepts were considered and a method was selected for development.

Bachalo, W. D.↗
NASA NTRS1990

Performance of alumina-supported Pt catalysts in an electron-beam-sustained CO2 laser amplifier

The performance of an alumina-supported Pt catalyst system used to maintain the gas purity in an electron-beam-sustained (636) isotope CO2 laser amplifier has been tested. The system characteristics using the two-zone, parallel flow reactor were determined for both continuous- and end-of-day reactor operation using on-line mass spectrometric sampling. The laser amplifier was run with an energy loading of typically 110 J-l/atm and an electron-beam current of 4 mA/sq cm. With these conditions and a pulse repetition frequency of 10 Hz for up to 10,000 shots, increases on the order of 100 ppm O2 were observed with the purifier on and 150 ppm with it off. The 1/e time recovery time was found to be approximately 75 minutes.

Cunningham, D. L.↗
NASA NTRS1993

A new facility for advanced rocket propulsion research

A new test facility was constructed at the NASA Lewis Research Center Rocket Laboratory for the purpose of conducting rocket propulsion research at up to 8.9 kN (2000 lbf) thrust, using liquid oxygen and gaseous hydrogen propellants. A laser room adjacent to the test cell provides access to the rocket engine for advanced laser diagnostic systems. The size and location of the test cell provide the ability to conduct large amounts of testing in short time periods, with rapid turnover between programs. These capabilities make the new test facility an important asset for basic and applied rocket propulsion research.

Zoeckler, Joseph G.↗
NASA NTRS2006

Advanced Energy Conversion Technologies and Architectures for Earth and Beyond

Research, development and studies of novel space-based solar power systems, technologies and architectures for Earth and beyond are needed to reduce the cost of clean electrical power for terrestrial use and to provide a stepping stone for providing an abundance of power in space, i.e., manufacturing facilities, tourist facilities, delivery of power between objects in space, and between space and surface sites. The architectures, technologies and systems needed for space to Earth applications may also be used for in-space applications. Advances in key technologies, i.e., power generation, power management and distribution, power beaming and conversion of beamed power are needed to achieve the objectives of both terrestrial and extraterrestrial applications. There is a need to produce "proof-ofconcept" validation of critical WPT technologies for both the near-term, as well as far-term applications. Investments may be harvested in near-term beam safe demonstrations of commercial WPT applications. Receiving sites (users) include ground-based stations for terrestrial electrical power, orbital sites to provide power for satellites and other platforms, future space elevator systems, space vehicle propulsion, and space surface sites. Space surface receiving sites of particular interest include the areas of permanent shadow near the moon s North and South poles, where WPT technologies could enable access to ice and other useful resources for human exploration. This paper discusses work addressing a promising approach to solar power generation and beamed power conversion. The approach is based on a unique high-power solar concentrator array called Stretched Lens Array (SLA) applied to both solar power generation and beamed power conversion. Since both versions (solar and laser) of SLA use many identical components (only the photovoltaic cells need to be different), economies of manufacturing and scale may be realized by using SLA on both ends of the laser power beaming system in a space solar power application. Near-term uses of this SLA-laser-SLA system may include terrestrial and space exploration in near Earth space. Later uses may include beamed power for bases or vehicles on Mars. Strategies for developing energy infrastructures in space which utilize this technology are presented. This dual use system produces electrical energy efficiently from either coherent light, such as from a highly coherent laser, or from conventional solar illumination. This allows, for example, supplementing solar energy with energy provided by highly coherent laser illumination during periods of low solar illumination or no illumination. This reduces the need for batteries and alternate sources of power. The capability of using laser illumination in a lowest order Gaussian laser mode provides means for transmitting power optically with maximum efficiency and precision over the long distances characteristic of space. A preliminary receiving system similar to that described here, has been produced and tested under solar and laser illumination. A summary of results is given.

Howell, Joe T.↗
DOE OSTI2026

An upgraded frequency-selectable laser source (FLS) calibrator for CMB bandpass characterization

One of the biggest challenges for Cosmic Microwave Background (CMB) experiments comes from the uncertainty in instrument bandpass calibration. Uncertainties in bandpass can limit foreground removal and spectral fitting, which are critical for inflationary and galaxy cluster measurements. CMB experiments currently use Fourier Transform Spectrometers (FTSes) to measure instrument bandpasses. However, FTS systems are currently systematics-limited, so significant improvements in bandpass measurements require novel calibrators. To this end, we developed a Frequency-selectable Laser Source (FLS) calibrator, which uses a laser with adjustable frequency coupled to a system that allows for laser power attenuation. Following initial testing with the first FLS prototype, we developed an upgraded version of the calibrator with improved performance. We present the upgrades to the FLS calibrator, the characterization of the upgraded calibrator and new laser source, and plans for testing with microwave instruments in the field.

Saunders, Lauren J. [Fermilab] (ORCID:000000016367↗
NASA NTRS2001

Geoscience Laser Altimeter System (GLAS) Instrument: Flight Loop Heat Pipe (LHP) Acceptance Thermal Vacuum Test

Two loop heat pipes (LHPs) are to be used for tight thermal control of the Geoscience Laser Altimeter System (GLAS) instrument, planned for flight in late 2001. The LHPs are charged with Propylene as a working fluid. One LHP will be used to transport 110 W from a laser to a radiator, the other will transport 160 W from electronic boxes to a separate radiator. The application includes a large amount of thermal mass in each LHP system and low initial startup powers. The initial design had some non-ideal flight design compromises, resulted in a less than ideal charge level for this design concept with a symmetrical secondary wick. This less than ideal charge was identified as the source of inadequate performance of the flight LHPs during the flight thermal vacuum test in October of 2000. We modified the compensation chamber design, re-built and charged the LHPs for a final LHP acceptance thermal vacuum test. This test performed March of 2001 was 100% successful. This is the last testing to be performed on the LHPs prior to instrument thermal vacuum test. This sensitivity to charge level was shown through varying the charge on a Development Model Loop Heat Pipe (DM LHP) and evaluating performance at various fill levels. At lower fills similar to the original charge in the flight units, the same poor performance was observed. When the flight units were re-designed and filled to the levels similar to the initial successful DM LHP test, the flight units also successfully fulfilled all requirements. This final flight Acceptance test assessed performance with respect to startup, low power operation, conductance, and control heater power, and steady state control. The results of the testing showed that both LHPs operated within specification. Startup on one of the LHPs was better than the other LHP because of the starter heater placement and a difference in evaporator design. These differences resulted in a variation in the achieved superheat prior to startup. The LHP with the lower superheat was sensitive to the thermal environment around the compensation chamber, while the LHP with the higher superheat (similar in design to DM LHP) was not. In response to the test results the placement of the starter heater will be optimized for the flight instrument testing for higher achieved superheat. This presentation discusses startup behavior, overall conductance of a radiator system, low power operation, high power operation, temperature control stability, and control heater power requirements as measured during this acceptance thermal vacuum test. A brief summary of 'lessons learned' will be included.

Baker, Charles↗
NASA NTRS1976

Laser absorption phenomena in flowing gas devices

A theoretical and experimental investigation is presented of inverse Bremsstrahlung absorption of CW CO2 laser radiation in flowing gases seeded with alkali metals. In order to motivate this development, some simple models are described of several space missions which could use laser powered rocket vehicles. Design considerations are given for a test call to be used with a welding laser, using a diamond window for admission of laser radiation at power levels in excess of 10 kW. A detailed analysis of absorption conditions in the test cell is included. The experimental apparatus and test setup are described and the results of experiments presented. Injection of alkali seedant and steady state absorption of the laser radiation were successfully demonstrated, but problems with the durability of the diamond windows at higher powers prevented operation of the test cell as an effective laser powered thruster.

Chapman, P. K.↗
NASA NTRS1994

Laser velocimeter data acquisition system for the Langley 14- by 22-foot subsonic tunnel. Software reference guide version 3.3

The Laser Velocimeter Data Acquisition System (LVDAS) in the Langley 14- by 22-Foot Tunnel is controlled by a comprehensive software package. The software package was designed to control the data acquisition process during wind tunnel tests which employ a laser velocimeter measurement system. This report provides detailed explanations on how to configure and operate the LVDAS system to acquire laser velocimeter and static wind tunnel data.

Jumper, Judith K.↗