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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 1,225 records · Page 68

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NASA NTRS2020

Free-Space Optical Communication for CubeSats in Low Lunar Orbit (LLO)

The NASA ARTEMIS Program will include LunaNet, a highly extensible, open architecture, lunar communications and navigation network. A constellation of CubeSats in Low Lunar Orbit (LLO), 100 km, could form an optical communications and navigation network as part of LunaNet, with terminals on the lunar surface, including mobile ones such as with astronauts and rovers. The proposed CubeSat nodes should provide data relay and navigational aid services. The proposed effort herein is to develop a fine pointing capability for laser beam pointing to augment body pointing by CubeSats. Body pointing was used by Aerospace Corporation for the CubeSats in LEO in NASA’s Optical Communications and Sensors Demonstration (OCSD) program [1]. Previously, this fine pointing capability was computer simulated for the OCSD program [2,3]. With fine pointing, the spot size on the Earth was reduced by a factor of eight with a reduction in laser output power by a factor of sixty-four, thereby mitigating the thermal load challenge on the CubeSats. The same reductions in spot size and laser output power can be achieved for CubeSats in LLO. A new method is described for optical data transmissions from satellites, which uses laser arrays for laser beam pointing. It combines a lens system and an array of vertical-cavity, surface-emitting lasers and photodetectors, an VCSEL/Photodetector Array, (both mature technologies), in a novel way. This system is applied to CubeSats in low lunar orbit, (LLO), which use body pointing. Also, It may be able to replace current architectures which use dynamical systems, (i.e., moving parts) to point the laser, and which may also use vibration isolation platforms. The computer simulations used the optics code, OpticStudio, from Zemax, LLC, which has the capabilities to model the laser source and diffraction effects from wave optics. These capabilities make it possible to model laser beam propagation over long space communication distances.

Goorjian, P. M.↗

NASA NTRS2022

ORCAS - Keck Instrument Development - ORKID

A new breed of space-ground hybrid observatory, the Orbiting Configurable Artificial Star (ORCAS) mission is working with the W. M. Keck Observatory (WMKO) to demonstrate the viability of diffraction-limited visible imaging from large ground telescopes. To support that, we have built and delivered ORKID (The ORCAS Keck Instrument Demonstrator) as an early visible-wavelength performance demonstration with the Keck II Adaptive Optics (AO) system. By enabling AO and flux calibration observations, the low-cost ORCAS/ORKID mission will deliver highly detailed images to support many scientific advances. A community driven observation plan will provide Great Observatory quality capabilities open to all US observers. These observations will result in unique science for the mission, while also complementing and extending space-borne science.

Eliad Peretz↗

DOE OSTI2025

Massive compression for high data rate macromolecular crystallography (HDRMX): impact on diffraction data and subsequent structural analysis

New higher-count-rate, integrating, large-area X-ray detectors with framing rates as high as 17400 images per second are beginning to be available. These will soon be used for specialized macromolecular crystallography experiments but will require optimal lossy compression algorithms to enable systems to keep up with data throughput. Some information may be lost. Can we minimize this loss with acceptable impact on structural information? To explore this question, we have considered several approaches: summing short sequences of images, binning to create the effect of larger pixels, use of JPEG-2000 lossy wavelet-based compression, and use of Hcompress, which is a Haar-wavelet-based lossy compression borrowed from astronomy. We also explore the effect of the combination of summing, binning, and Hcompress or JPEG-2000. In each of these last two methods one can specify approximately how much one wants the result to be compressed from the starting file size. These provide particularly effective lossy compressions that retain essential information for structure solution from Bragg reflections.

47 OTHER INSTRUMENTATION↗

NASA NTRS1988

Superconductivity in the high-Tc Bi-Ca-Sr-Cu-O system - Phase identification

Four phases are observed in superconducting Bi-Ca-Sr-Cu-O samples. The superconducting phase, with onset temperature near 120 K, is a 15.4-A-layered compound with composition near Bi2Ca1Sr2Cu2O9 and an A-centered orthorhombic unit subcell 5.41 x 5.44 x 30.78 A. X-ray diffraction and electron microscopy data are consistent with a structure of alternating perovskite and Bi2O2 layers. High-resolution transmission electron microscopy images reveal a b-axis superstructure of 27.2 A, numerous (001) stacking faults, and other defects.

Hazen, R. M.↗

NASA NTRS1992

A solar magnetic and velocity field measurement system for Spacelab 2: The Solar Optical Universal Polarimeter (SOUP)

The Solar Optical Universal Polarimeter (SOUP) flew on the shuttle mission Spacelab 2 (STS-51F) in August, 1985, and collected historic solar observations. SOUP is the only solar telescope on either a spacecraft or balloon which has delivered long sequences of diffraction-limited images. These movies led to several discoveries about the solar atmosphere which were published in the scientific journals. After Spacelab 2, reflights were planned on the shuttle Sunlab mission, which was cancelled after the Challenger disaster, and on a balloon flights, which were also cancelled for funding reasons. In the meantime, the instrument was used in a productive program of ground-based observing, which collected excellent scientific data and served as instrument tests. Given here is an overview of the history of the SOUP program, the scientific discoveries, and the instrument design and performance.

Tarbell, Theodore D.↗

NASA NTRS2003

Optomechanical Alignment of the Grating Wheel Mechanism for a Ground-based, Cryogenic, Near-Infrared Astronomy Instrument

We describe the population, optomechanical alignment, and alignment verification of near-infrared gratings on the grating wheel mechanism (GWM) for the Infrared Multi- Object Spectrometer (IRMOS). IRMOS is a cryogenic (80 K) facility instrument for the Mayall Telescope (3.8 m) at Kitt Peak National Observatory and a MEMS spectrometer concept demonstrator for NASA's James Webb Space Telescope. The IRMOS optics, bench, and mechanisms are predominantly made of Al 6061 -T651. The GWM consists of 13 planar diffraction gratings and one flat imaging mirror (58 x 57 mm), each mounted at a unique compound angle on a 31.8 cm diameter gear. The Al 6061 grating substrates are stress relieved for enhanced cryogenic performance and the optical surface is replicated from an off-the-shelf master. The imaging mirror is diamond turned and post-polished. The grating mechanism spans a projected diameter of approximately 48cm when fully assembled, utilizes several flexure designs throughout the system to accommodate thermal gradient situations, and is controlled using custom software with an off-the-shelf controller. Each optic is aligned in six degrees of freedom relative to the GWM coordinate system, which is defined relative to an optical alignment cube mounted at the center of the gear. The tip/tilt (Rx, Ry) orientation of a given grating is measured using the zero-order return from an autocollimating theodolite. Each optic's mount includes a one-piece shim located between the optic and the gear. The shim is machined to fine align each optic. We also describe alignment verification, where grating diffractive properties are compared to model predictions.

Gutkowski, Sharon M.↗

DOE OSTI2024

Magneto-transport study on Sn-rich Sn 1–x Ge x thin films enabled by CdTe buffer layer

α-Sn, generally known as gray tin, has attracted significant scientific interest due to its potential to host novel topological phases. Studying the transport properties of α-Sn thin films grown on the InSb substrate has been challenging, as the InSb substrate also significantly contributes to the transport properties. In this article, we report a novel approach to epitaxially grow α-Sn thin films on an InSb substrate with a resistive buffer layer of CdTe. Thin films of α–Sn 1–x Ge x (x = 0, 0.025) alloy of 15 nm thickness have been grown using molecular beam epitaxy. The high quality of the samples has been determined through high-resolution x-ray diffraction. The CdTe buffer layer has high resistance and acts as an insulating virtual substrate, which significantly suppresses contribution from InSb. Magnetotransport measurements show clear Shubnikov–de Hass oscillations in α–Sn 1–x Ge x (x = 0, 0.025) thin films. A change in oscillation frequency is observed upon alloying with Ge, implying a modification in the electronic structure and demonstrating the effectiveness of the CdTe buffer layer approach. Furthermore, this work provides a new approach that enables the electronic transport characterization of the α–Sn 1–x Ge x alloy system, which enables the study of the topological quantum states using electronic transport and their device applications.

36 MATERIALS SCIENCE↗

DOE OSTI2023

Ultrafast X-Ray Scattering Reveals Composite Amplitude Collective Mode in the Weyl Charge Density Wave Material ( TaSe 4 ) 2 I

Here we report ultrafast x-ray scattering experiments of the quasi-1D charge density wave (CDW) material (TaSe 4 ) 2⁢ I following ultrafast infrared photoexcitation. From the time-dependent diffraction signal at the CDW sidebands we identify a 0.11 THz amplitude mode derived primarily from a transverse acoustic mode of the high-symmetry structure. From our measurements we determine that this mode interacts with the valence charge indirectly through another collective mode, and that the CDW system in (TaSe 4 ) 2 ⁢I has a composite nature supporting multiple dynamically active structural degrees of freedom.

36 MATERIALS SCIENCE↗

DOE OSTI2026

Predominant Proton Insertion during Electrochemical Cycling of ε-VOPO 4 in a Nonaqueous Ca-Ion Electrolyte

Calcium-ion batteries (CIBs) are promising for next-generation energy storage systems. However, many reported Ca-ion storage mechanisms lack direct structural evidence, raising concerns that the observed electrochemistry may instead originate from proton insertion. Herein, we investigate the electrochemical cycling of a VOPO 4 electrode in an aprotic Ca electrolyte with trace water to clarify the charge storage mechanism. While electrochemistry, elemental analysis, and X-ray absorption spectroscopy seem to support Ca-ion intercalation in the VOPO 4 electrode, X-ray diffraction and electron microscopy unequivocally show proton insertion as the predominant charge storage mechanism. The apparent variation of Ca content in the electrode with the state of charge is attributed to the formation and dissolution of Ca-containing precipitates on the surface of VOPO 4 particles. Our work demonstrates the propensity of proton participation in the intercalation reaction in Ca-ion batteries and the necessity of structural evidence in understanding reactions in multivalent electrochemical systems.

Wang, Jiwei [Binghamton University, NY (United Sta↗

NASA NTRS1977

Physical-chemical examination of the N2O3-SO3-H2O system

It was found that when (NO)HSO4 is added to absolute H2SO4, specific conductivity rises sharply, possibly due to an increase in mutual interionic effects and viscosity as the (NO)HSO4 concentration rises. The addition of SO3 to the solution yielded a precipitate; a combination of analysis, IR spectroscopy and X-ray diffraction techniques indicated that this precipitate was (NO)HS2O7.

Linstroem, C.↗

NASA NTRS2003

Comprehensive Study of Hydrated IDPs: X-Ray Diffraction, IR Spectroscopy and Electron Microscopic Analysis

Chondritic hydrated interplanetary dust particles (IDPs) comprise up to 50% of all IDPs collected in the stratosphere(1). Although much is known about the mineralogy, chemistry and carbon abundance of hydrated IDPs (2-4) controversies still exist regarding their formation, history, and relationship to other primitive solar system materials. Hydrated IDPs are generally believed to be derived from asteroidal sources that have undergone some degree of aqueous alteration. However, the high C contents of hydrated IDPs (by 2 to 6X CI levels (3,4) indicate that they are probably not derived from the same parent bodies sampled by the known chondritic meteorites. We report the comprehensive study of individual hydrated IDPs. The strong depletion in Ca (I) has been used as a diagnostic feature of hydrated IDPs. The particles are embedded in elemental sulfur or low viscosity epoxy and ultramicrotomed thin sections are observed using a transmission electron microscope (TEM) equipped with an energy-dispersive X-ray detector (EDX) followed by other measurements including: 1) FTIR microspectroscopy to understand the significant constraints on the organic functionality and the nature of the C-bearing phases and 2) powder X-ray difiaction using a synchrotron X-ray source to understand the bulk mineralogy of the particles.

Nakamura, K.↗

DOE OSTI2025

Computing virtual dark-field X-ray microscopy images of complex discrete dislocation structures from large-scale molecular dynamics simulations

Dark-field X-ray microscopy (DFXM) is a novel diffraction-based imaging technique that non-destructively maps the local deformation from crystalline defects in bulk materials. While studies have demonstrated that DFXM can spatially map 3D defect geometries, it is still challenging to interpret DFXM images of the high-dislocation-density systems relevant to macroscopic crystal plasticity. This work develops a scalable forward model to calculate virtual DFXM images for complex discrete dislocation structure(s) (DDS) obtained from atomistic simulations. Our new DDS-DFXM model integrates a non-singular formulation for calculating the local strain from the DDS and an efficient geometrical optics algorithm for computing the DFXM image from the strain field. We apply the model to complex DDS obtained from a large-scale molecular dynamics simulation of compressive loading on single-crystal silicon. Simulated DFXM images exhibit prominent contrast for dislocation features between the multiple slip systems, demonstrating the potential of DFXM to resolve features from dislocation multiplication. In conclusion, the integrated DDS-DFXM model provides a toolbox for DFXM experimental design and image interpretation in the context of bulk crystal plasticity for a range of measurements across shock plasticity and the broader materials science community.

X-ray imaging↗

DOE OSTI2020

Correlations between electronic order and structural distortions and their ultrafast dynamics in the single-layer manganite P r 0.5 C a 1.5 Mn O 4

Time-resolved x-ray diffraction experiments on the half-doped single-layered manganite Pr 0.5 Ca 1.5 Mn O 4 are used to monitor the ultrafast photoinduced dynamics of the structural distortion associated with the charge and orbital ordering (CO/OO). As in the nonlayered three-dimensional counterpart, the ordered phase melts in less than 100 fs after 800-nm photoexcitation and subsequently partially recovers due to thermal equilibration of electronic and vibrational systems. Photoexciting Pr 0.5 Ca 1.5 Mn O 4 below the transition temperature of a second structural phase transition that occurs around 146 K (deep inside the CO/OO phase) releases this structural transition, but progresses on a much slower timescale. Finally, this additional reduction of crystal symmetry, which we ascribe to a further tilt of the oxygen octahedra, can thus be considered to be only weakly coupled to CO/OO. Furthermore, static hard-x-ray and resonant soft-x-ray diffraction at the Mn L 2,3 edges experiments identify correlations between structural distortions and electronic order in thermal equilibrium.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2023

FIRST RESULTS FROM Nb3Sn COATINGS OF 2.6 GHz Nb SRF CAVITIES USING DC CYLINDRICAL MAGNETRON SPUTTERING SYSTEM

A DC cylindrical magnetron sputtering system has been commissioned and operated to deposit Nb3Sn onto 2.6 GHz Nb SRF cavities. After optimizing the deposition conditions in a mock-up cavity, Nb-Sn films are deposited first on flat samples by multilayer sequential sputtering of Nb and Sn, and later annealed at 950 °C for 3 hours. X-ray diffraction of the films showed multiple peaks for the Nb3Sn phase and Nb (substrate). No peaks from any Nb-Sn compound other than Nb3Sn were detected. Later three 2.6 GHz Nb SRF cavities are coated with ~1 µm thick Nb3Sn. The first Nb3Sn coated cavity reached close to Eacc = 8 MV/m, demonstrating a quality factor Q0 of 3.2 × 108 at Tbath = 4.4 K and Eacc = 5 MV/m, about a factor of three higher than that of Nb at this temperature. Q0 was close to 1.1 × 109, dominated by the residual resistance, at 2 K and Eacc = 5 MV/m. The Nb3Sn coated cavities demonstrated Tc in the range of 17.9 ? 18 K. Here, we present the commissioning experience, system optimization, and the first results from the Nb3Sn fabrication on flat samples and SRF cavities.

Shakel, M.S.↗

DOE OSTI2023

FIRST RESULTS FROM Nb3Sn COATINGS OF 2.6 GHz Nb SRF CAVITIES USING DC CYLINDRICAL MAGNETRON SPUTTERING SYSTEM

Shakel, M. S.↗

DOE OSTI2023

Tetracopper σ‐Bound μ ‐Acetylide and ‐Diyne Units Stabilized by a Naphthyridine‐based Dinucleating Ligand

Abstract Reactions of a dicopper(I) tert ‐butoxide complex with alkynes possessing boryl or silyl capping groups resulted in formation of unprecedented tetracopper(I) μ ‐acetylide/diyne complexes that were characterized by NMR and UV/Vis spectroscopy, mass spectrometry and single‐crystal X‐ray diffraction. These compounds possess an unusual μ 4 ‐ η 1 : η 1 : η 1 : η 1 coordination mode for the bridging organic fragment, enforced by the rigid and dinucleating nature of the ligand utilized. Thus, the central π system remains unperturbed and accessible for subsequent reactivity and modification. This has been corroborated by addition of a fifth copper atom, giving rise to a pentacopper acetylide complex. This work may provide a new approach by which metal‐metal cooperativity can be exploited in the transformation of acetylide and diyne groups to a variety of substrates, or as a starting point for the controlled synthesis of copper(I) alkyne‐containing clusters.

Ríos, Pablo↗

DOE OSTI2023

Tetracopper σ‐Bound μ ‐Acetylide and ‐Diyne Units Stabilized by a Naphthyridine‐based Dinucleating Ligand

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2025

Measurement of interfacial thermal resistance in high-energy-density matter

Heat transport across interfaces is a ubiquitous phenomenon with many unresolved aspects. In particular, it is unknown if an interfacial thermal resistance (ITR) occurs in matter with high-energy-density where free electrons dominate the heat conduction. Here, we report on the first experimental evidence that a significant heat barrier is present between two different regions of high-energy-density matter: a strongly heated tungsten wire and a surrounding plastic layer that stays relatively cold. We use diffraction-enhanced imaging to track the time evolution of density discontinuities and reconstruct the temperature evolution in the quasi-stationary stage. The clear signatures of a temperature jump demonstrate the importance of the ITR for strongly heated systems with far-reaching implications for interpreting experiments and applications like inertial confinement fusion.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗