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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

OAST Space Theme Workshop. Volume 3: Working group summary. 7: Material (M-1). A. Statement. B. Technology needs (form 1). C. Priority assessment (form 2)

The approach of matching technology areas with various themes needs was not effective for the materials and thermal control discipline because of the diversity of requirements for each. Top priorities were evolved from the advanced space transportation system and the space power platform because these are essential building blocks in fulfilling some of the other themes. Important needs identified include life long-life cryogenic cooling systems for sensors, masers, and other devices and the needs for lightweight nuclear shielding materials for nuclear electric propulsion.

Source record↗
NASA NTRS1976

OAST Theme Workshop. Volume 3: Working group summary. 8: Structures, dynamics (M-2). A. Statement. B. Technology needs (form 1). C. Priority assessments (form 2)

A technology program on large space structures was defined to respond to common need perceived for five of the six themes. Greatly expanded power, facilities, and communications/sensing requirements appear to demand a new structures technology for construction in space. Requirements to construct huge structural arrays with precision surfaces in space will need creative research efforts to identify practical structural elements and construction techniques. Requirements for advanced transportation structures were defined to respond to the space transportation theme. Because of the criticality of thermal structures to achieve lower cost transportation systems, renewed emphasis on technology in this area is recommended. A second technology needing renewed emphasis is the area of recovery and landing technology structures to permit full reuse of launch vehicle propulsion elements.

Source record↗
NASA NTRS1986

Remote Sensing Information Sciences Research Group, Santa Barbara Information Sciences Research Group, year 3

Research continues to focus on improving the type, quantity, and quality of information which can be derived from remotely sensed data. The focus is on remote sensing and application for the Earth Observing System (Eos) and Space Station, including associated polar and co-orbiting platforms. The remote sensing research activities are being expanded, integrated, and extended into the areas of global science, georeferenced information systems, machine assissted information extraction from image data, and artificial intelligence. The accomplishments in these areas are examined.

Estes, J. E.↗
NASA NTRS1988

A dual-armed free flyer

In this summary, we present the main conclusions and results of a design study conducted by a group of 25 students at the University of Maryland. The students, all participants in the spring 1988 courses ENEE488Q and ENEE418 in the Electrical Engineering Department, considered the problem of designing a free-flying space robot for applications in satellite servicing. In addition to the paper study, a subgroup of eight students undertook the ambitious task of designing and building a laboratory testbed for the concept of a free flyer. This subgroup has already completed the main fabrication of the mechanical hardware and most of the onboard electronics. When completed by the end of the summer, the testbed will consist of a seven-degree-of-freedom dual-armed planar robot that will float on an air table and carry out various commanded tasks. All the fabrication and testing is being conducted in the Intelligent Servosystems Laboratory at the University of Maryland. The project team split up into subgroups as follows: (1) articulation concepts 1 and 2, to study competing ideas for the overall systems architecture and manipulator design; (2) real time control systems group; (3) a computer graphics group to provide animations of a planar design; (4) a mechanical hardware design group for the laboratory testbed; and (5) a control systems hardware design group for the same.

Source record↗
NASA NTRS2001

Effects of Cage Type and NASA Rodent Food Bar in Male Sprague-Dawley Rats

Early prototype caging for the rodent Advanced Animal Habitat (P-AAH) for the International Space Station (ISS) is currently being tested. In this five week study, effects of the wire-bottom P-AAH cages and specialized NASA rodent food bars (FB) were compared to standard vivarium cages (VIV) with corn-cob, litter-filled bottoms, and standard Purina rat chow (CH). Ninety-six male Sprague-Dawley rats were divided into four treatment groups (24 rats/treatment): Group 1) VIV+CH, Group 2) P-AAH+CH, Group 3) VIV+FB, and Group 4) P-AAH+FB. Each VIV and P-AAH cage housed three and six rats, respectively. After five weeks of treatment rats were weighed, euthanized, and blood samples were collected. Weights of liver (LIV), kidney (KID), brain (BRN), epididymal fat (EPI), and perirenal fat (PERI) were also measured. Statistical analysis to compare differences between groups was performed by standard analysis of variance procedures (ANOVA) with a significance level of pLO.05. Results indicated P-AAH housed rats had significantly lower body weights (BW), LIV weights, and LIV/BW than VIV housed rats. FB fed rats had significantly lower blood urea nitrogen (BUN) levels and LIV/BW than CH fed rats. In addition, FB fed rats had significantly higher cholesterol (CHOL) levels, EPI/BW, PERI/BW, and total fat (EPI+PERI)/BW than CH fed rats. The P-AAH+FB group had significantly lower EPI, BRN, and total fat than VIV+FB rats. VIV+FB rats had significantly higher BRN, EPI, PERI, and total fat than VIV+CH rats. Triglycerides (TG), KID, KID/BW, and BRN/BW were not significantly different among treatment groups. These findings provide valuable information regarding cage design and food bar suitability for long-term use on the ISS.

Lau, Angela↗
NASA NTRSDate not supplied

Autonomous Control for Arbitrary Thruster Configurations and Mass Properties in Special Euclidean Group SE(3)

Most current methods for determining maneuvers and thrust firing sequences depend on explicit and predetermined commands generated by a combination of on-board systems and ground-based human-in-the-loop methods. For spacecraft and space structures with changing mass properties and thruster configurations, such as the Deep Space Gateway as it changes configurations throughout its lifetime, determining these commands can be time-consuming and computationally intensive. However, recent work within the Lie GroupSE (3) has offered ways of autonomously determining the location, power, precision, and capabilities of thrusters in any arbitrary position. Furthermore, a method for determining thruster firing sequences based on an arbitrary control input (both translational and rotational in a coupled, 6-element vector) and arbitrary thruster configurations has also recently been developed. When combining these methods, any spacecraft with any mass properties and thruster configurations can be understood in terms of controllability limits and thruster firing sequences can be generated quickly and with low computational load, thus extending the autonomous capabilities of deep space missions. In this work, this method is presented and explored in terms of computational load, robustness in the presence of uncertainty, and overall performance. The capabilities of this method are also examined in the case of the Deep Space Gateway both in fully controllable configurations and uncontrollable configurations.

Control↗
DOE OSTI2025

Linearized Pair-Density Functional Theory with Spin–Orbit Coupling

Here, we include spin–orbit coupling (SOC) effects in linearized pair-density functional theory (L-PDFT), which is a multistate extension of multiconfiguration pair-density functional theory (MC-PDFT). Both 1-electron and 2-electron SOC integrals are computed using Breit-Pauli and Douglas–Kroll–Hess Hamiltonians in the atomic mean-field approximation. SO-L-PDFT removes the unphysical J-symmetry breaking observed in MC-PDFT. The accuracy of SO-L-PDFT is validated by calculations of zero-field splittings, fine-structure excitation energies, and low-energy excited-state spectra for a diverse group of atoms and molecules spanning the whole range of the periodic table, including atoms of groups 3, 11, and 13–17, the Ce 3+ and U 5+ ions, group 16 monohydrides, group 17 monoxides, lanthanide hexachlorides ([CeCl 6 ] 3− , [PrCl 6 ] 3− , and [NdCl 6 ] 3− ), actinyl ions ([UO 2 ] + , [NpO 2 ] 2+ ), and tricarbonatoactinyl complexes ([UO 2 (CO 3 ) 3 ] 5− , [NpO 2 (CO 3 ) 3 ] 4− ). We also compare the results to new spin–orbit-inclusive calculations by single-state and multistate multireference perturbation theory.

Hamiltonians↗
DOE OSTI2023

Selective hydrogenation via precise hydrogen bond interactions on catalytic scaffolds

Abstract The active site environment in enzymes has been known to affect catalyst performance through weak interactions with a substrate, but precise synthetic control of enzyme inspired heterogeneous catalysts remains challenging. Here, we synthesize hyper-crosslinked porous polymer (HCPs) with solely -OH or -CH 3 groups on the polymer scaffold to tune the environment of active sites. Reaction rate measurements, spectroscopic techniques, along with DFT calculations show that HCP-OH catalysts enhance the hydrogenation rate of H-acceptor substrates containing carbonyl groups whereas hydrophobic HCP- CH 3 ones promote non-H bond substrate activation. The functional groups go beyond enhancing substrate adsorption to partially activate the C = O bond and tune the catalytic sites. They also expose selectivity control in the hydrogenation of multifunctional substrates through preferential substrate functional group adsorption. The proposed synthetic strategy opens a new class of porous polymers for selective catalysis.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1996

Solar Electromagnetic Radiation Study for Solar Cycle 22: Solar Ultraviolet Irradiance, 120 to 300 NM: Report of Working Groups 2 and 3 of SOLERS 22

This report summarizes the activities of Working Group 2 and Working Group 3 of the SOLax Electromagnetic Radiation Study for Solar Cycle 22 (SOLERS22) Program. The international (SOLERS22) is Project 1.2 of the Solar-Terrestrial Energy Program (STEP) sponsored by SCOSTEP, a committee of the International Council of Scientific Unions). SOLERS22 is comprised of five Working Groups, each concentrating on a specific wave-length range: WG-1 - visible and infrared, WG-2 - mid-ultraviolet (200 < A < 300 nm), WG-3 - Far-ultraviolet (lambda greater than 100 and lambda less than 200 nanometers), WG-4 - extreme-ultraviolet (lambda greater than 10 and lambda less than 100 nm), and WG-5 - X-ray (lambda greater than 1 and lambda less than 10 nano meters). The overarching goals of SOLERS22 are to: 1) establish daily solar irradiance values in the specified wavelength ranges, 2) consider the evolving solar structures as the cause of temporal variations, and 3) understand the underlying physical processes driving these changes.

Rottman, G. J.↗
DOE OSTI2024

Degradation Mechanism of Phosphate‐Based Li‐NASICON Conductors in Alkaline Environment

NASICON-type Li conductors (Li-NASICON) have traditionally been regarded as promising candidates for solid-state Li-air battery applications because of their stability in water and ambient air. However, the presence of water in the cathode of a Li-air battery can induce a highly alkaline environment by modifying the discharge product from Li 2 O 2 to LiOH which can potentially degrade cathode and separator materials. This study investigates the alkaline stability of common Li-NASICON chemistries through a systematic experimental study of LiTi x Ge 2-x (PO 4 ) 3 (LTGP) with varying x = 0–2.0. Density functional theory calculations are combined to gain a mechanistic understanding of the alkaline instability. It is demonstrated that the instability of LTGP in an alkaline environment is mainly driven by the dissolution of PO 4 3– groups, which subsequently precipitate as Li 3 PO 4 . The introduction of Ti facilitates the formation of a Ti-rich compound on the surface that eventually passivates the material, but only after significant bulk degradation. Consequently, phosphate-based Li-NASICON materials exhibit limited alkaline stability, raising concerns about their viability in humid Li-air batteries.

25 ENERGY STORAGE↗
NASA NTRS1998

The ROSAT Deep Survey: Optical Identification, Photometry and Spectra of X-Ray Sources in the Lockman Field - 2

The ROSAT Deep Survey includes a complete sample of 50 X-ray sources with fluxes in the 0.5 - 2 keV band larger than 5.5 x 10(exp -15)erg/sq cm/s in the Lockman field (Hasinger et al., Paper 1). We have obtained deep broad-band CCD images of the field and spectra of many optical objects near the positions of the X-ray sources. We define systematically the process leading to the optical identifications of the X-ray sources. For this purpose, we introduce five identification (ID) classes that characterize the process in each case. Among the 50 X-ray sources, we identify 39 AGNs, 3 groups of galaxies, 1 galaxy and 3 galactic stars. Four X-ray sources remain unidentified so far; two of these objects may have an unusually large ratio of X-ray to optical flux.

Schmidt, M.↗
DOE OSTI2023

DFT-Based Calculation of Molecular Hyperpolarizability and SFG Intensity of Symmetric and Asymmetric Stretch Modes of Alkyl Groups

Vibrational sum frequency generation (SFG) spectroscopy has been extensively used for obtaining structural information of molecular functional groups at two-dimensional (2D) interfaces buried in the gas or liquid medium. Although the SFG experiment can be done elegantly, interpreting the measured intensity in terms of molecular orientation with respect to the lab coordinate is quite complicated. One of the main reasons is the difficulty of determining the hyperpolarizability tensors of even simple molecules that govern their SFG responses. The single-bond polarizability derivative (SBPD) model has been proposed to estimate the relative magnitude of SFG-active hyperpolarizability by assuming that the perturbation associated to each vibration is negligible. In this study, density functional theory (DFT) was used to calculate the polarizability and dipole derivative tensors of the CH 3 stretch mode of CH 3 I, CH 3 CH 2 I, CH 3 OH, CH 3 CH 2 OH. Then, the hyperpolarizability tensors of symmetric and asymmetric vibration modes were calculated considering the Boltzmann distribution of representative conformers, which allowed theoretical calculation of their SFG intensities at all polarization combinations as a function of the tilt angle of the CH 3 group with respect to the surface normal direction. Then the ratios of the calculated SFG intensities for the CH 3 peaks used in experimental studies for the CH 3 tilt angle determination were compared. This comparison clearly showed the effect of vibrational coupling among neighboring functional groups. As a result, this study presents new parameters that can be used in determining the average tilt angle of the CH 3 group at the 2D interface with SFG measurements as well as limitations of the method.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Physical inconsistencies in the representation of the ocean heat-carbon nexus in simple climate models

The Ocean Heat-Carbon Nexus, linking ocean heat and carbon uptake, is crucial for understanding climate responses to cumulative carbon dioxide (CO 2 ) emissions and to net zero CO 2 emissions. It results from a suite of processes involving the exchange of heat and carbon across the sea-air interface as well as their storage below the mixed layer and redistribution by the ocean large-scale circulation. The Ocean Heat and Carbon Nexus is assumed to be consistently represented across two modelling platforms used in the latest IPCC assessments: the Earth System Models (ESMs) and the Simple Climate Models (SCMs). However, our research shows significant deficiencies in state-of-the-art SCMs in replicating the ocean heat-carbon nexus of ESMs due to a crude treatment of the ocean thermal and carbon cycle coupling. With one SCM, we show that a more realistic heat-to-carbon uptake ratio exacerbates the projected warming by 0.1 °C in low overshoot scenarios and up to 0.2 °C in high overshoot scenarios. It is therefore critical to explore how SCMs’ physical inconsistencies, such as the representation of the ocean heat-carbon nexus, can affect future warming projections used in climate assessments, not just by SCMs in Working Group 3 but also by ESMs in Working Group 1 via SCM-driven emission-to-concentration translation.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

Iodine speciation in basaltic melts at depth

The speciation of iodine in basalts has been investigated by combining in situ X-ray diffraction at high pressures and temperatures up to 4.9 GPa and 1600 °C, and Raman spectroscopy on recovered high pressure glasses at ambient conditions. Both methods point to iodine being oxidized in basalts, whether molten or quenched as glasses. Observed interatomic distances and Raman vibrational modes are consistent with iodine being dissolved as complex iodate groups alike polyiodates or periodates, not as IO$^-_3$ groups. Iodine speciation in basalts therefore seems to reflect a trend amongst halogens, with lighter chlorine bonding to network modifying cations, and bromine changing affinity from network modifying cations to oxygen anions under pressure. In the absence of a fluid aqueous phase, iodine could thus reach the Earth’s surface in basaltic magmas as an oxide, not as a reduced species.

58 GEOSCIENCES↗
NASA NTRS2012

Hybrid bandgap engineering for super-hetero-epitaxial semiconductor materials, and products thereof

"Super-hetero-epitaxial" combinations comprise epitaxial growth of one material on a different material with different crystal structure. Compatible crystal structures may be identified using a "Tri-Unity" system. New bandgap engineering diagrams are provided for each class of combination, based on determination of hybrid lattice constants for the constituent materials in accordance with lattice-matching equations. Using known bandgap figures for previously tested materials, new materials with lattice constants that match desired substrates and have the desired bandgap properties may be formulated by reference to the diagrams and lattice matching equations. In one embodiment, this analysis makes it possible to formulate new super-hetero-epitaxial semiconductor systems, such as systems based on group IV alloys on c-plane LaF.sub.3; group IV alloys on c-plane langasite; Group III-V alloys on c-plane langasite; and group II-VI alloys on c-plane sapphire.

Park, Yeonjoon↗
NASA NTRS2010

VLBI2010: An Overview

The first concrete actions toward a next generation system for geodetic VLBI began in 2003 when the IVS initiated Working Group 3 to investigate requirements for a new system. The working group set out ambitious performance goals and sketched out initial recommendations for the system. Starting in 2006, developments continued under the leadership of the VLBI2010 Committee (V2C) in two main areas: Monte Carlo simulators were developed to evaluate proposed system changes according to their impact on IVS final products, and a proof-of-concept effort sponsored by NASA was initiated to develop next generation systems and verify the concepts behind VLBI2010. In 2009, the V2C produced a progress report that summarized the conclusions of the Monte Carlo work and outlined recommendations for the next generation system in terms of systems, analysis, operations, and network configuration. At the time of writing: two complete VLBI2010 signal paths have been completed and data is being produced; a number of VLBI2010 antenna projects are under way; and a VLBI2010 Project Executive Group (V2PEG) has been initiated to provide strategic leadership.

Petrachenko, Bill↗