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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 361 records · Page 20
All sourcesNASA NTRSDOE OSTI
NASA NTRS1980

Conceptual design study of concentrator enhanced solar arrays for space applications. 2kW Si and GaAs systems at 1 AU

The effect of concentration level on the specific power for a deployable, thin, gallium arsenide cell array in geosynchronous orbit for 10 years in conjunction with a two dimensional flat plate trough concentrator (V trough) and also with a multiple flat plate concentrator was investigated as well as the effects for a conventional silicon cell array on a rigid substrate. For application to a thin GaAs array at 1 AU for 10 years, the V trough produces a 19% benefit in specific power and a dramatic reduction in array area, while the multiple flat plate collector design is not only of no benefit, but is a considerable detriment. The benefit it achieves by reducing array area is duplicated by the 2D design. For the silicon array on a rigid substrate, improvement in performance due to a concentrator with ordinary mirror coating is quite small: 9% increase in specific power, and 13% reduction in array area. When the concentrator mirrors are coated with an improved cold mirror coating, somewhat more significant results are obtained: 31% specific power improvement; and 27% area reduction. In both cases, a 10 year exposure reduces BOL output by 23%.

Source record↗
NASA NTRS1992

Single liquid source plasma-enhanced metalorganic chemical vapor deposition of high-quality YBa2Cu3O(7-x) thin films

High quality YBa2Cu3O(7-x) films were grown in-situ on LaAlO3 (100) by a novel single liquid source plasma-enhanced metalorganic chemical vapor deposition process. The metalorganic complexes M(thd) (sub n), (thd = 2,2,6,6-tetramethyl-3,5-heptanedionate; M = Y, Ba, Cu) were dissolved in an organic solution and injected into a vaporizer immediately upstream of the reactor inlet. The single liquid source technique dramatically simplifies current CVD processing and can significantly improve the process reproducibility. X-ray diffraction measurements indicated that single phase, highly c-axis oriented YBa2Cu3O(7-x) was formed in-situ at substrate temperature 680 C. The as-deposited films exhibited a mirror-like surface, had transition temperature T(sub cO) approximately equal to 89 K, Delta T(sub c) less than 1 K, and Jc (77 K) = 10(exp 6) A/sq cm.

Zhang, Jiming↗
DOE OSTI2025

X-Ray Imaging and Spectroscopy Mission

The X-Ray Imaging and Spectroscopy Mission (XRISM) is a joint mission between the Japan Aerospace Exploration Agency (JAXA) and the National Aeronautics and Space Administration (NASA) in collaboration with the European Space Agency (ESA). In addition to the three space agencies, universities and research institutes from Japan, North America, and Europe have joined to contribute to developing satellite and onboard instruments, data-processing software, and the scientific observation program. XRISM is the successor to the ASTRO-H (Hitomi) mission, which ended prematurely in 2016. Its primary science goal is to examine astrophysical problems with precise, high-resolution X-ray spectroscopy. XRISM promises to discover new horizons in X-ray astronomy. It carries a 6 × 6 pixelized X-ray microcalorimeter on the focal plane of an X-ray mirror assembly (Resolve) and a co-aligned X-ray CCD camera (Xtend) that covers the same energy band over a large field of view. XRISM utilizes the Hitomi heritage, but all designs were reviewed. The attitude and orbit control system was improved in hardware and software. The spacecraft was launched from the JAXA Tanegashima Space Center on 2023 September 6 (UTC). During the in-orbit commissioning phase, the onboard components were activated. Although the gate valve protecting the Resolve sensor with a thin beryllium X-ray entrance window was not yet opened, scientific observation started in 2024 February with the planned performance verification observation program. The nominal observation program commenced with the following guest observation program beginning in 2024 September.

Astronomy and AstroPhysics↗
DOE OSTI2021

Tuning Hybrid exciton–Photon Fano Resonances in Two-Dimensional Organic–Inorganic Perovskite Thin Films

As easy-to-grow quantum wells with narrow excitonic features at room temperature, two-dimensional (2D) Ruddleson–Popper perovskites are promising for realizing novel nanophotonic devices based on exciton–photon interactions. Here, we demonstrate a distinct hybrid exciton–photon Fano resonance in (C 4 H 9 NH 3 ) 2 PbI 4 thin films prepared via spin coating. Using a classical coupled-oscillator model and finite-difference time-domain simulations, we link the Fano interference to the coupling of the exciton with the Rayleigh-like scattering of the film microstructure. Combining colloidal plasmonic cavities with the 2D perovskite films, we demonstrate tuning of the Fano resonance. In combination with silver nanoparticles, the exciton–photon Fano interference couples to the in-plane plasmonic modes with indications of Rabi splitting. By creating a nanoparticle on mirror geometry, we address the out-of-plane excitonic component, reaching an intermediate coupling regime. Furthermore, these structures suggest possible photonic targets for biomolecular self-assembly applications.

2D perovskites↗
NASA NTRS2005

Stable Polyimides for Terrestrial and Space Uses

Polyimides of a recently developed type have an attractive combination of properties, including low solar absorptivity (manifested as low color) when cast into thin films, resistance to atomic oxygen and ultraviolet radiation, solubility in organic solvents, high glass-transition temperatures, and high thermal stability. The focus of the development work was on polymers that can endure the space environment and that have specific combinations of properties for use on Gossamer spacecraft. Because of their unique combination of properties, these polymers are also expected to find use in a variety of other applications on Earth as well as in space. Examples of other space applications include membranes on antennas, second-surface mirrors, thermal optical coatings, and multilayer thermal insulation. For both terrestrial and space applications, these polyimides can be processed into various forms, including films, fibers, foams, threads, adhesives, and coatings.

Connell, John W.↗
DOE OSTI2021

Designing high-performance superconductors with nanoparticle inclusions: Comparisons to strong pinning theory

One of the most promising routes for achieving high critical currents in superconductors is to incorporate dispersed, non-superconducting nanoparticles to control the dissipative motion of vortices. However, these inclusions reduce the overall superconducting volume and can strain the interlaying superconducting matrix, which can detrimentally reduce T c . Consequently, an optimal balance must be achieved between the nanoparticle density n p and size d. Determining this balance requires garnering a better understanding of vortex–nanoparticle interactions, described by strong pinning theory. Here, we map the dependence of the critical current on nanoparticle size and density in (Y 0.77 , Gd 0.23 )Ba 2 Cu 3 O 7-δ films in magnetic fields of up to 35 T and compare the trends to recent results from time-dependent Ginzburg–Landau simulations. We identify consistency between the field-dependent critical current J c (B) and expectations from strong pinning theory. Specifically, we find that J c ∝ B -α , where α decreases from 0.66 to 0.2 with increasing density of nanoparticles and increases roughly linearly with nanoparticle size d/ξ (normalized to the coherence length). At high fields, the critical current decays faster (~B -1 ), suggesting that each nanoparticle has captured a vortex. When nanoparticles capture more than one vortex, a small, high-field peak is expected in J c (B). Due to a spread in defect sizes, this novel peak effect remains unresolved here. Finally, we reveal that the dependence of the vortex creep rate S on nanoparticle size and density roughly mirrors that of α, and we compare our results to low-T nonlinearities in S(T) that are predicted by strong pinning theory.

36 MATERIALS SCIENCE↗
NASA NTRS2023

Cryolite Overcoated Aluminum Reflectors for Far-Ultraviolet Spectroscopy

Aluminum (Al) mirrors are conventionally protected with metal-fluoride coatings (e.g., MgF2, LiF, or AlF3) immediately after deposition to prevent oxidation and preserve its far-ultraviolet (FUV) spectral efficiency. However, the resulting FUV reflectance of the aluminum reflector is limited by the metal-fluoride overcoat film index of refraction, morphology, stoichiometry, and its absorption cut-off in the lower end of the FUV spectra. Cryolite (sodium hexafluoroaluminate, Na3AlF6) emerges as a potential candidate to preserve the aluminum FUV reflectance due to its relatively lower index of refraction in the visible to ultraviolet; therefore, allowing for the thin-film design of highly spectral efficient reflectors over a wide spectral range. We investigate the use of cryolite in aluminum reflector FUV coating design. The deposited aluminum reflector overcoated with cryolite will be examined in terms of spectral efficiency and environmental durability. The deposited cryolite overcoat will be evaluated in terms of optical constants and structural properties. Preliminary results have shown that the use of cryolite as an overcoat to protect aluminum would yield unprecedented results as an optimal Hydrogen Lyman-alpha (HLyα) spectral line reflector, with experimental reflectance values >96%.

optical coatings↗
NASA NTRSDate not supplied

Cryolite Overcoated Aluminum Reflectors for Far-Ultraviolet Spectroscopy

Aluminum (Al) mirrors are conventionally protected with metal-fluoride coatings (e.g., MgF 2 , LiF, or AlF 3 ) immediately after deposition to prevent oxidation and preserve its far-ultraviolet (FUV) spectral efficiency. However, the resulting FUV reflectance of the aluminum reflector is limited by the metal-fluoride overcoat film index of refraction, morphology, stoichiometry, and its absorption cut-off in the lower end of the FUV spectra. Cryolite (sodium hexafluoroaluminate, Na 3 AlF 6 ) emerges as a potential candidate to preserve the aluminum FUV reflectance due to its relatively lower index of refraction in the visible to ultraviolet; therefore, allowing for the thin-film design of highly spectral efficient reflectors over a wide spectral range. We investigate the use of cryolite in aluminum reflector FUV coating design. The deposited aluminum reflector overcoated with cryolite will be examined in terms of spectral efficiency and environmental durability. The deposited cryolite overcoat will be evaluated in terms of optical constants and structural properties. Preliminary results have shown that the use of cryolite as an overcoat to protect aluminum would yield unprecedented results as an optimal Hydrogen Lyman-alpha (HLyα) spectral line reflector, with experimental reflectance values >96%.

optical coating↗
NASA NTRS2003

Ising model of cardiac thin filament activation with nearest-neighbor cooperative interactions

We have developed a model of cardiac thin filament activation using an Ising model approach from equilibrium statistical physics. This model explicitly represents nearest-neighbor interactions between 26 troponin/tropomyosin units along a one-dimensional array that represents the cardiac thin filament. With transition rates chosen to match experimental data, the results show that the resulting force-pCa (F-pCa) relations are similar to Hill functions with asymmetries, as seen in experimental data. Specifically, Hill plots showing (log(F/(1-F)) vs. log [Ca]) reveal a steeper slope below the half activation point (Ca(50)) compared with above. Parameter variation studies show interplay of parameters that affect the apparent cooperativity and asymmetry in the F-pCa relations. The model also predicts that Ca binding is uncooperative for low [Ca], becomes steeper near Ca(50), and becomes uncooperative again at higher [Ca]. The steepness near Ca(50) mirrors the steep F-pCa as a result of thermodynamic considerations. The model also predicts that the correlation between troponin/tropomyosin units along the one-dimensional array quickly decays at high and low [Ca], but near Ca(50), high correlation occurs across the whole array. This work provides a simple model that can account for the steepness and shape of F-pCa relations that other models fail to reproduce.

Evaluation Studies↗
DOE OSTI2026

Substrate-Directed Underlayer Growth of Bilayer MoS 2 Revealed by Mo Isotope Labeling

Direct control over the vertical formation sequence and stacking registry in van der Waals (vdW) bilayers is essential for device performance and moiré engineering yet difficult to resolve unambiguously with conventional probes. Here, we use Mo isotope labeling in a two-step chemical vapor deposition process to synthesize bilayer MoS 2 and trace its vertical formation on common substrates. By combining site-selective laser thinning, Raman spectroscopy, time-of-flight secondary ion mass spectrometry, and atomic-resolution scanning transimission electron microscopy (STEM), we find a clear substrate dependence: on SiO 2 /Si, the second layer nucleates and grows beneath the first (underlayer), whereas on sapphire, it forms on top (overlayer). Density functional theory indicates that a larger equilibrium interfacial separation and weaker MoS 2 –substrate interactions on amorphous SiO 2 permit confined interfacial diffusion and underlayer nucleation, whereas stronger interactions and smaller separations on sapphire favor overlayer growth. On SiO 2 , confined epitaxy templates commensurate 2H, 3R, and mixed bilayers, as confirmed by second harmonic generation spectroscopy and STEM. During underlayer coalescence, embedded mirror-twin grain boundaries stitch atomically sharp 2H|3R junctions via alternating 4|8 ring motifs. Molecular-dynamics simulations reveal that these alternating 4|8 motifs accommodate interlayer vdW coupling and locally modulate the stacking registry. These results provide mechanistic insight into confined epitaxial growth and establish isotope labeling as a powerful probe of two-dimensional materials synthesis.

MoS2↗
DOE OSTI2022

Ultrafast Laser Material Damage Simulation—A New Look at an Old Problem

The chirped pulse amplification technique has enabled the generation of pulses of a few femtosecond duration with peak powers multi-Tera and Peta–Watt in the near infrared. Its implementation to realize even shorter pulse duration, higher energy, and higher repetition rate laser systems relies on overcoming the limitations imposed by laser damage of critical components. In particular, the laser damage of coatings in the amplifiers and in post-compression optics have become a bottleneck. The robustness of optical coatings is typically evaluated numerically through steady-state simulations of electric field enhancement in multilayer stacks. However, this approach cannot capture crucial characteristics of femtosecond laser induced damage (LID), as it only considers the geometry of the multilayer stack and the optical properties of the materials composing the stack. This approach neglects that in the interaction of an ultrashort pulse and the materials there is plasma generation and associated material modifications. Here, we present a numerical approach to estimate the LID threshold of dielectric multilayer coatings based on strong field electronic dynamics. In this dynamic scheme, the electric field propagation, photoionization, impact ionization, and electron heating are incorporated through a finite-difference time-domain algorithm. We applied our method to simulate the LID threshold of bulk fused silica, and of multilayer dielectric mirrors and gratings. The results are then compared with experimental measurements. The salient aspects of our model, such as the implementation of the Keldysh photoionization model, the impact ionization model, the electron collision model for ‘low’-temperature, dense plasma, and the LID threshold criterion for few-cycle pulses are discussed.

36 MATERIALS SCIENCE↗
NASA NTRS1990

Multiple axis reticle

A reticle permits the alignment of three orthogonal axes (X, Y and Z) that intersect at a common target point. Thin, straight filaments are supported on a frame. The filaments are each contained in a different orthogonal plane (S sub xy, S sub xz, and S sub yz) and each filament intersects two of the three orthogonal axes. The filaments, as viewed along the frame axis, give the appearance of a triangle with a V extending from each triangle vertex. When axial alignment is achieved, the filament portions adjacent to a triangle vertex are seen (along the axis of interest) as a right-angle cross, whereas these filament portions are seen to intersect at an oblique angle when axial misalignment occurs. The reticle is open in the region near the target point leaving ample space for alignment aids such as a pentaprism or a cube mirror.

Barns, Chris E.↗
NASA NTRS1973

Properties of vacuum-evaporated boron films

The work on the properties of thin boron films made by vacuum evaporation of elemental boron using an electron beam as the energy source is reported. The program aimed at characterizing the properties of vacuum evaporated films. The work was directed toward those variables considered to be important in affecting the tensile strength of the boron films. In general, the thickness of the films was less than 0.002 in. The temperature of the substrate on which the boron was condensed was found to be most important. Three distinctly different forms of boron deposit were produced. Although the transition temperature was not sharply defined, at substrate temperatures of less than approximately 600 deg C the boron deposits were amorphous to X-ray. If the substrate were highly polished, the deposits were black and mirror-like. For substrates with coefficients of thermal expansion close to that of boron, the deposits were then continuous and uncracked. The studies suggest that the potential continues to exist for film-type composites to have both high strength and high modulus.

Feakes, F.↗
DOE OSTI2025

Observation of a Giant Goos-Hänchen Shift for Matter Waves

The Goos-Hänchen (GH) shift describes a phenomenon in which a specularly reflected beam is translated along the reflecting surface such that the incident and reflected rays no longer intersect at the surface. Using a neutron spin-echo technique and a specially designed magnetic multilayer mirror, we have measured the relative phase between the reflected up and down neutron spin states in total reflection. The relative GH shift calculated from this phase shows a strong resonant enhancement at a particular incident neutron wave vector, which is due to a waveguiding effect in one of the magnetic layers. Calculations based on the observed phase difference between the neutron states indicate a propagation distance along the waveguide layer of 0.65 mm for the spin-down state, which we identify with the magnitude of the giant GH shift. The existence of a physical GH shift is confirmed by the observation of neutron absorption in the waveguide layer. Here, we propose ways in which our experimental method may be exploited for neutron quantum-enhanced sensing of thin magnetic layers.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
NASA NTRS2003

Development of a Prototype Nickel Optic for the Constellation-X Hard-X-Ray Telescope

The Constellation-X mission, planned for launch in 2011, will feature an array of hard-x ray telescopes with a total collecting area goal of 1500 square centimeters at 40 keV. Various technologies are currently being investigated for the optics of these telescopes including multilayer-coated Eletroformed-Nickel-Replicated (ENR) shells. The attraction of the ENR process is that the resulting full-shell optics are inherently stable and offer the promise of good angular resolution and enhanced instrument sensitivity. The challenge for this process is to meet a relatively tight weight budget with a relatively dense material (rho nickel = 9 grams per cubic centimeters.) To demonstrate the viability of the ENR process we are fabricating a prototype HXT mirror module to be tested against a competing segmented-glass-shell optic. The ENR prototype will consist of 5 shells of diameters from 150 mm to 280 mm and of 426 mm total length. To meet the stringent weight budget for Con-X, the shells will be only 150 micron thick. The innermost of these will be coated with Iridium, while the remainder will be coated with graded-density multilayers. Mandrels for these shells are currently under fabrication (Jan 03), with the first shells scheduled for production in February 03. A tentative date of late Summer has been set for prototype testing. Issues currently being addressed are the control of stresses in the multiplayer coating and ways of mitigating their effects on the figure of the necessarily thin shells. Also, the fabrication, handling and mounting of these shells without inducing permanent figure distortions. A full status report on the prototype optic will be presented along with test results as available.

Basso, S.↗
NASA NTRS2005

NASA Tech Briefs, July 2005

Thin-Film Resistance Heat-Flux Sensors Circuit Indicates that Voice-Recording Disks are Nearly Full Optical Sensing of Combustion Instabilities in Gas Turbines Topics include: Crane-Load Contact Sensor; Hexagonal and Pentagonal Fractal Multiband Antennas; Multifunctional Logic Gate Controlled by Temperature; Multifunctional Logic Gate Controlled by Supply Voltage; Power Divider for Waveforms Rich in Harmonics; SCB Quantum Computers Using iSWAP and 1-Qubit Rotations; CSAM Metrology Software Tool; Update on Rover Sequencing and Visualization Program; Selecting Data from a Star Catalog; Rotating Desk for Collaboration by Two Computer Programmers; Variable-Pressure Washer; Magnetically Attached Multifunction Maintenance Rover; Improvements in Fabrication of Sand/Binder Cores for Casting; Solid Freeform Fabrication of Composite-Material Objects; Efficient Computational Model of Hysteresis; Gauges for Highly Precise Metrology of a Compound Mirror; Improved Electrolytic Hydrogen Peroxide Generator; High-Power Fiber Lasers Using Photonic Band Gap Materials; Ontology-Driven Information Integration; Quantifying Traversability of Terrain for a Mobile Robot; More About Arc-Welding Process for Making Carbon Nanotubes; Controlling Laser Spot Size in Outer Space; or Software-Reconfigurable Processors for Spacecraft.

Source record↗
NASA NTRS2000

Design and Flight Testing of an Inflatable Sunshield for the NGST

The Next Generation Space Telescope (NGST) mission is scheduled to launch in 2007 and be stationed at L2 for a mission life of ten years. The large aperture mirror and optical detectors aboard NGST require shielding from the constant solar energy seen at this orbit. The government reference NGST design, called the Yardstick, baselined a sunshield using an inflation deployment system. During the formulation phase, NGST is spending approximately 25% of the overall budget to foster the development of new technology. The goal is to develop and demonstrate enabling or enhancing technology and provide innovative solutions for the design of the NGST observatory. Inflatable technology falls in the category of enhancing technology due to its advantages in weight, stowed volume and cost. The Inflatable Sunshield in Space (ISIS) flight experiment will provide a realistic space flight demonstration of an inflatable sunshield. The supporting technology development program will provide an information base for the design, manufacture, assembly and testing of large thin membranes and inflatable structural elements for space structures. The ISIS experiment will demonstrate the feasibility of using inflatable technology to passively cool optical systems for NGST and provide correlation between analytical predictions and on orbit results. The experiment will be performed on a Hitchhiker/Space Shuttle mission in late 2001. The ISIS mission is an effort to address several major technical challenges of the NGST inflatable sunshield, namely controlled inflation deployment, plenarity and separation of large stretched membranes, space rigidization of inflatable booms, and dynamic modeling and simulation. This paper will describe the design of the flight experiment and the testing to be performed on-orbit.

Adams, Michael L.↗
NASA NTRS2011

NASA Tech Briefs, March 2011

Topics covered include: Optimal Tuner Selection for Kalman-Filter-Based Aircraft Engine Performance Estimation; Airborne Radar Interferometric Repeat-Pass Processing; Plug-and-Play Environmental Monitoring Spacecraft Subsystem; Power-Combined GaN Amplifier with 2.28-W Output Power at 87 GHz; Wallops Ship Surveillance System; Source Lines Counter (SLiC) Version 4.0; Guidance, Navigation, and Control Program; Single-Frame Terrain Mapping Software for Robotic Vehicles; Auto Draw from Excel Input Files; Observation Scheduling System; CFDP for Interplanetary Overlay Network; X-Windows Widget for Image Display; Binary-Signal Recovery; Volumetric 3D Display System with Static Screen; MMIC Replacement for Gunn Diode Oscillators; Feature Acquisition with Imbalanced Training Data; Mount Protects Thin-Walled Glass or Ceramic Tubes from Large Thermal and Vibration Loads; Carbon Nanotube-Based Structural Health Monitoring Sensors; Wireless Inductive Power Device Suppresses Blade Vibrations; Safe, Advanced, Adaptable Isolation System Eliminates the Need for Critical Lifts; Anti-Rotation Device Releasable by Insertion of a Tool; A Magnetically Coupled Cryogenic Pump; Single Piezo-Actuator Rotary-Hammering Drill; Fire-Retardant Polymeric Additives; Catalytic Generation of Lift Gases for Balloons; Ionic Liquids to Replace Hydrazine; Variable Emittance Electrochromics Using Ionic Electrolytes and Low Solar Absorptance Coatings; Spacecraft Radiator Freeze Protection Using a Regenerative Heat Exchanger; Multi-Mission Power Analysis Tool; Correction for Self-Heating When Using Thermometers as Heaters in Precision Control Applications; Gravitational Wave Detection with Single-Laser Atom Interferometers; Titanium Alloy Strong Back for IXO Mirror Segments; Improved Ambient Pressure Pyroelectric Ion Source; Multi-Modal Image Registration and Matching for Localization of a Balloon on Titan; Entanglement in Quantum-Classical Hybrid; Algorithm for Autonomous Landing; Quantum-Classical Hybrid for Information Processing; Small-Scale Dissipation in Binary-Species Transitional Mixing Layers; Superpixel-Augmented Endmember Detection for Hyperspectral Images; Coding for Parallel Links to Maximize the Expected Value of Decodable Messages; and Microwave Tissue Soldering for Immediate Wound Closure.

Source record↗