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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 451 records · Page 25

Satellite power system concept development and evaluation program. Volume 2: System definition

The system level results of the system definition studies performed by NASA as a part of the Department of Energy/NASA satellite power system concept development and evaluation program are summarized. System requirements and guidelines are discussed as well as the major elements that comprise the reference system and its design options. Alternative system approaches including different system sizes, solid state amplifier (microwave) concepts, and laser power transmission system cost summaries are reviewed. An overview of the system analysis and planning efforts is included. The overall study led to the conclusion that the reference satellite power system concept is a feasible baseload source of electrical power and, within the assumed guidelines, the minimum cost per kilowatt is achieved at the maximum output of 5 gigawatts to the utility grid. Major unresolved technical issues include maximum allowable microwave power density in the ionosphere and performance/mass characteristics of laser power transmission systems.

Source record↗

Thermal Lens Measurement in Diode-Pumped Nd:YAG Zig-Zag Slab

A major advantage that solid state zig-zag slab lasers have over conventional rod-based designs is that a much weaker thermal lens is produced in the slab when side-pumped with Quasi-CW laser diode arrays, particularly if the pump radiation is kept well away from the Brewster-cut ends. This paper reports on a rather strong thermal lens produced when diode pump radiation is collimated into a narrow portion of the zig-zag slab. The collimation of multi-bar pump packages to increase brightness and improve overlap is a direct consequence of designs which seek to maximize performance and efficiency. Our slab design employed a 8.1 cm x 2.5 mm x 5 mm slab with opposing Brewster end faces. It was pumped through the 2.5 mm direction by seven laser diode array packages, each housing four 6OW diode bars, 1 cm in width. The pump face, anti-reflection (AR) coated at 809 nm, was 6.8 cm in width and the 8.1 cm opposing side, high-reflection (HR) coated at 809 nm, reflected the unabsorbed pump beam for a second pass through the slab.

Smoak, M. C.↗

Spacecraft Cabin Atmospheric Major Constituent Monitoring Using Off-the-Shelf Techniques

Since the beginning of the crewed space exploration program, the National Aeronautics and Space Administration (NASA) recognized the need to monitor the composition of a spacecraft cabin atmosphere. Typically, major constituent monitoring has been limited to nitrogen, oxygen, carbon dioxide, and water vapor. For the International Space Station, mass spectroscopy was selected as the baseline technology for this task. Recently, new techniques for monitoring major atmospheric constituents have matured commercially making them viable for crewed spacecraft applications. These techniques have advantages over the mass spectroscopy and electrochemically-based instruments used on board the /SS and Shuttle. Fast laser diode oxygen analysis, solid-state infrared carbon dioxide detection, and thin-film capacitive humidity detection are among the emerging techniques. Representative instruments employing these techniques have been selected and tested to demonstrate their potential for crewed spacecraft applications. A summary of testing results is provided.

Perry, Jay L.↗

Microfluidic Devices for Chemical and Biochemical Analysis in Microgravity

One often touted benefit of "Lab-on-a-Chip" devices is their potential for use in remote environments. The ultimate remote environment is outer space, and NASA has multiple needs in the area of analytical sensing capability in such an environment. In particular, we are interested in integrating microfluidic devices with NASA bioreactor systems. In such an integrated system, the microfluidic device will serve as a biosensor and be used for both feedback control and for detecting various bioproducts produced by cells cultured in the NASA bioreactors. As a first step in demonstrating the ability of microfluidic devices to operate under the extreme environmental conditions found in outer space, we constructed a portable, battery operated platform for testing under reduced gravity conditions on a NASA KC-135 reduced gravity research aircraft, (AKA "the vomit comet"). The test platform consisted of a microchip, two 0-8kV high voltage power supplies, a high voltage switch, a solid-state diode-pumped green laser, a channel photomultiplier, and an inertial mass measurement unit, all under the control of a laptop computer and powered by 10 D-cell alkaline batteries. Over the course of 4 KC-135 flights, 1817 fast electrophoretic separations of 4 amino acids and/or proteins were performed in a variety of gravitational environments including zero-G, Martian-G, lunar-G, and 2-G. Results from these experiments will be presented and discussed.

Roman, Gregory T.↗

Solid-state optical refrigerator for cryogenic cooling of payloads

A solid-state optical refrigerator for cryogenic cooling of a payload, the solid-state optical refrigerator including a laser cooling crystal including a first material and a dopant material; a thermal link including a second material, the thermal link being bonded to the laser cooling crystal and the thermal link being configured to be thermally linked to the payload to transfer heat conductively from the payload to the laser cooling crystal via the thermal link; and a vacuum chamber housing the laser cooling crystal and the thermal link, the vacuum chamber and thermal link having a combination of shape and coating such that laser and fluorescence light reflected off a wall of the vacuum chamber and laser and fluorescence light propagating within the thermal link are not incident on the payload.

Hehlen, Markus Peter↗

Recent Progress Made in the Development of High-Energy UV Transmitter

In this paper, the status of an all-solid-state UV converter development for ozone sensing applications is discussed. A high energy Nd:YAG laser for pumping the UV converter arrangement was recently reported. The pump is an all-solid-state, single longitudinal mode, and conductively cooled Nd:YAG laser operating at 1064 nm wavelength. Currently, this pump laser provides an output pulse energy of greater than 1J/pulse at 50 Hz PRF and a pulsewidth of 22 ns with an electrical-to-optical system efficiency of greater than 7% and a M(sup 2) value of approx. 2. The spatial profile of the output beam is a rectangular super Gaussian. This Nd:YAG pump laser has been developed to pump the nonlinear optics based UV converter arrangement to generate 320 nm and 308 nm wavelengths by means of 532 nm wavelength. Previously, this UV converter arrangement has demonstrated IR-to-UV conversion efficiency of 24% using a flash lamp pumped laser providing a round, flat top spatial profile. Recently, the UV converter was assembled and tested at NASA LaRC for pumping with the diode pumped Nd:YAG laser. With current spatial profile, the UV converter was made operational. Current efforts to maximize the nonlinear conversion efficiency by refining its spatial profile to match RISTRA OPO requirements are progressing.

Prasad, Narasimha S.↗

Injection seeded, diode pumped regenerative ring Nd:YAG amplifier for spaceborne laser ranging technology development

A small, all solid state, regenerative ring amplifier designed as a prototype for space application is discussed. Novel features include dual side pumping of the Nd:YAG crystal and a triangular ring cavity design which minimizes the number of optical components and losses. The amplifier is relatively small (3 ns round trip time) even though standard optical elements are employed. The ring regeneratively amplifies a 100 ps single pulse by approximately 10(exp 5) at a repetition rate of 10 to 100 Hz. The amplifier is designed to be injection seeded with a pulsed, 100 ps laser diode at 1.06 microns, but another Nd:YAG laser system supplying higher pulse energies was employed for laboratory experiment. This system is a prototype laser oscillator for the Geoscience Laser Ranging System (GLRS) platform. Results on measurements of beam quality, astigmatism, and gain are given.

Coyle, D. Barry↗

Clarifying the formation of equiaxed grains and microstructural refinement in the additive manufacturing of Ti-Cu

Controlling microstructural evolution in metallic additive manufacturing (AM) is difficult, especially in producing refined as-built grains instead of coarse, directional grains. Traditional solutions involve adding inoculants to AM feedstocks, but titanium (Ti) alloys cannot employ this approach without producing detrimental secondary phases. Ti-Cu (Ti-copper) alloys offer a solution through constitutional supercooling and/or solid state thermal cycling under AM conditions. This work analyzes a compositionally graded directed energy deposition (DED) Ti-Cu build, single-melt laser tracks, and dilatometric heat treatments to evaluate if, when, and by what mechanism(s) microstructural refinement occurs. Refinement by inoculation of unmelted powder particles was also considered. Constitutional supercooling produced no net microstructural refinement as any equiaxed dendrites which form are remelted with new deposition. This finding agreed with solidification modeling of powder bed fusion-laser beam (PBF-LB) and DED builds. Solid state thermal cycling refined microstructures only during ex-situ dilatometric heat treatments, suggesting build parameter optimization is needed to achieve refinement in-situ. Accidental heterogeneous nucleation on unmelted Ti powder, originating from the different thermophysical properties of Ti and Cu, provided the most significant microstructural refinement. This work systematically assesses the microstructural refinement mechanisms of Ti-Cu in AM builds and offers insights into microstructural control in eutectoid alloys.

36 MATERIALS SCIENCE↗

Leveraging the redox activities of cerium and dibenzotetrathiafulvalene to discover a photo-responsive magnetic material

Stimuli-responsive changes in lanthanide-based materials are a promising research direction. In this study, [DBTTF] 4 [Ce 2 Cl 10 ] DBTTF = dibenzotetrathiafulvalene (1) was synthesized by a light-induced crystallization, where photo-oxidation of DBTTF enables formation of the cerium dimer [Ce 2 Cl 10 ] 4− . Intermolecular interactions between the stacked organic units of the crystal result in charge transfer bands in the visible-NIR (near-infrared) region, evident in the solid-state absorption spectrum upon comparison with the solution spectrum. The assignments of the sublattice oxidation states were made with single-crystal X-ray diffraction (SC-XRD) structural characterization, Raman spectroscopy, X-ray absorption spectroscopy, and magnetometry. Continuous 532 nm laser irradiation of the microcrystalline solid modulates the redox states in 1, leading to ∼40% reduction in the observed magnetization at 2 K. Density functional theory PBE+U/HSE06 band structure calculations predict Mott insulating behavior in 1, with a bandgap of 0.54/0.81 eV, and further support the conjecture that the observed photo-induced change in magnetization results from electron transfer from the [Ce 2 Cl 10 ] 4− anions to the π-stacked [DBTTF] 2 2+ organic dimer subunits. An enhancement in conductivity is similarly observed upon 532 nm irradiation, determined by single-crystal transport measurements. The findings reveal that photo-responsive lanthanide-based materials can be achieved by integration of redox-active organic moieties with redox-active lanthanide cations for the realization of switchable, photo-magnetic materials.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Development of Mesospheric Sodium Laser Beacon for Atmospheric Adaptive Optics

A solid-state source of long pulse length, sodium-resonance radiation was developed for the purpose of generating an artificial star in the earth's mesospheric sodium layer. This radiation is generated by sum-frequency mixing the output of a 1.064 micron Nd:YAG laser with the output of a 1.319-micron Nd:YAG laser. By operating these lasers at wavelengths very close to the peak of their tuning curves, it is possible to match the wavelength of the sum-frequency radiation to that of the sodium D2 adsorption wavelength. Two pulsed laser systems were constructed, one producing as much as 0.6 J of sodium resonance radiation at a 10-Hz repetition rate and another producing as much as 24 mJ at a 840-Hz repetition rate. In both laser systems, the 1.06-micron and 1.32-micron Nd:YAG lasers are configured as mode-locked master oscillators followed by power amplifiers. Other aspects of this project are presented.

Jeys, T. H.↗

Pulsed Laser Deposition of High Temperature Protonic Films

Pulsed laser deposition has been used to fabricate nanostructured BaCe(0.85)Y(0.15)O3- sigma) films. Protonic conduction of fabricated BaCe(0.85)Y(0.15)O(3-sigma) films was compared to sintered BaCe(0.85)Y(0.15)O(3-sigma). Sintered samples and laser targets were prepared by sintering BaCe(0.85)Y(0.15)O(3-sigma) powders derived by solid state synthesis. Films 1 to 8 micron thick were deposited by KrF excimer laser on porous Al2O3 substrates. Thin films were fabricated at deposition temperatures of 700 to 950 C at O2 pressures up to 200 mTorr using laser pulse energies of 0.45 - 0.95 J. Fabricated films were characterized by X-ray diffraction, electron microscopy and electrical impedance spectroscopy. Single phase BaCe(0.85)Y(0.15)O(3-sigma) films with a columnar growth morphology are observed with preferred crystal growth along the [100] or [001] direction. Results indicate [100] growth dependence upon laser pulse energy. Electrical conductivity of bulk samples produced by solid state sintering and thin film samples were measured over a temperature range of 100 C to 900 C. Electrical conduction behavior was dependent upon film deposition temperature. Maximum conductivity occurs at deposition temperature of 900 oC; the electrical conductivity exceeds the sintered specimen. All other deposited films exhibit a lower electrical conductivity than the sintered specimen. Activation energy for electrical conduction showed dependence upon deposition temperature, it varied

Dynys, Fred W.↗

Ionization-Based Optical Structures for the Control of Short-Pulse Lasers (Abbreviated LDRD Report)

The intensity of light from the highest-power lasers is limited by the size of the optics required to amplify, compress, transport, and focus a laser beam. Indeed, optics damage puts strict constraints on the laser energy density that solid optics can sustain; this leads to enormous optics sizes and limits the maximum intensity that these lasers can achieve. In this project we investigated new types of diffractive optics based on mixtures of neutral gas and plasmas. The basic idea is to interfere laser beams in a gas near the ionization threshold, so that plasma is created in the constructive interference regions (i.e., the “bright” fringes of the interference pattern) while the destructive interference regions remain a neutral gas. The resulting refractive index modulation, due to the different indices in gas vs. plasma, effectively turns such structures into diffractive optics elements. We proposed several new types of optics based on this general concept: i) reflection gratings, which can act as mirrors of “pulse cleaners” to eliminate laser pre-pulse; ii) transmission gratings, as part of a new type of pulse compression scheme with the potential to achieve laser intensities orders of magnitude above what is currently feasible using solid-state optics; and iii) holographic lenses, to focus high-power lasers. We conducted laboratory experiments which demonstrated high efficiency reflection gratings, paving the way for practical applications of our new concepts.

47 OTHER INSTRUMENTATION↗

Ultrafast time-resolved 2D imaging of laser-driven fast electron transport in solid density matter using an x-ray free electron laser

High-power, short-pulse laser-driven fast electrons can rapidly heat and ionize a high-density target before it hydrodynamically expands. The transport of such electrons within a solid target has been studied using two-dimensional (2D) imaging of electron-induced Kα radiation. However, it is currently limited to no or picosecond scale temporal resolutions. Here, we demonstrate femtosecond time-resolved 2D imaging of fast electron transport in a solid copper foil using the SACLA x-ray free electron laser (XFEL). An unfocused collimated x-ray beam produced transmission images with sub-micron and ~10 fs resolutions. The XFEL beam, tuned to its photon energy slightly above the Cu K-edge, enabled 2D imaging of transmission changes induced by electron isochoric heating. Time-resolved measurements obtained by varying the time delay between the x-ray probe and the optical laser show that the signature of the electron-heated region expands at ~25% of the speed of light in a picosecond duration. Time-integrated Cu Kα images support the electron energy and propagation distance observed with the transmission imaging. The x-ray near-edge transmission imaging with a tunable XFEL beam could be broadly applicable for imaging isochorically heated targets by laser-driven relativistic electrons, energetic protons, or an intense x-ray beam.

47 OTHER INSTRUMENTATION↗

Sensors and detectors in NASA's future missions

Advances in electronics are responsible for major improvements in NASA's sensing and detection capabilities for future space missions. Technologies such as charge-transfer devices, tunable diode lasers, millimeter and submillimeter wave solid-state receiver components, large-scale circuit integration, new electronic materials and processing techniques, and novel detector electronics are contributing to the goal of a tenfold increase in the capacity of data collection from future platforms and will be used for space exploration and utilization.

Rubin, B.↗

A wide-band monolithic quasi-optical power meter for millimeter- and submillimeter-wave applications

A novel monolithic power meter has been developed for submillimeter-wave applications (100 GHz to 10 THz). The detector is a large-area bismuth bolometer integrated on a 1.2-micron-thick dielectric membrane. This approach results in a wide-band, high-responsivity detector. The power meter is simple to fabricate, is inexpensive, and can be easily calibrated using a low-frequency network. Quasi-optical measurements at 90, 140, and 240 GHz show that the bolometer is polarization-independent and could be modeled by a simple transmission line model. Absolute power measurements at 90, 140, and 240 GHz show a + or - 5 percent accuracy and agree well with a calibrated Anritsu power meter at 90 GHz. Potential application areas are power calibration, antenna coupling efficiency measurements, and absolute power measurements from solid-state devices and far-infrared lasers at submillimeter wavelengths. Absolute output power measurements on a 220-280 GHz tripler using the quasi-optical power meter are presented as an application example.

Ling, Curtis C.↗

Progress Toward Demonstrating a High Performance Optical Tape Recording Technology

This paper discusses the technology developments achieved during the first year of a program to develop a high performance digital optical tape recording device using a solid state, diode pumped, frequency doubled green laser source. The goal is to demonstrate, within two years, useful read/write data transfer rates to at least 100 megabytes per second and a user capacity of up to one terabyte per cartridge implemented in a system using a '3480' style mono-reel tape cartridge.

Oakley, W. S.↗

The DUV Stability of Superlattice-Doped CMOS Detector Arrays

JPL and Alacron have recently developed a high performance, DUV camera with a superlattice doped CMOS imaging detector. Supperlattice doped detectors achieve nearly 100% internal quantum efficiency in the deep and far ultraviolet, and a single layer, Al2O3 antireflection coating enables 64% external quantum efficiency at 263nm. In lifetime tests performed at Applied Materials using 263 nm pulsed, solid state and 193 nm pulsed excimer laser, the quantum efficiency and dark current of the JPL/Alacron camera remained stable to better than 1% precision during long-term exposure to several billion laser pulses, with no measurable degradation, no blooming and no image memory at 1000 fps.

silicon detectors↗

Dragonfly mass spectrometer titan environment optical damage testing

The Dragonfly Mass Spectrometer (DraMS) being developed at NASA’s Goddard Space Flight Center will use a solid-state 266-nm pulsed Nd:YAG laser perform compositional analysis on the surface of Titan. Due to the high fluence of the focused pulse energy on the laser’s beam steering unit (BSU) and the mass spectrometer window, the damage threshold of these optics in a Titan atmosphere needed to be characterized. This paper details the test setup and the successful demonstration of testing the highest fluence optics for the expected mission duration of 2 million laser pulses in a Titan-relevant atmosphere.

Matt Mullin↗