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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 757 records · Page 42
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

Tethers and their role in the Space Exploration Initiative

This paper addresses some potential applications for tethers in space, and describes a mission designed to deploy a satellite from a Delta II launch vehicle, by NASA's Small Expendable Deployer System, via a 46 km long tether. The mission, targeted for 1993, will contribute to the U.S. Space Exploration Initiative, and along with the shuttle flight of the tethered satellite system, TSS1, will be one of the first attempts to experimentally characterize the dynamics of a tethered system. Data taken from two experimental packages onboard the satellite will be analyzed to verify mathematical simulations related to tether dynamics.

Bankston, Cheryl D.↗
NASA NTRS2004

Advanced Video Guidance Sensor and Next Generation Autonomous Docking Sensors

In recent decades, NASA's interest in spacecraft rendezvous and proximity operations has grown. Additional instrumentation is needed to improve manned docking operations' safety, as well as to enable telerobotic operation of spacecraft or completely autonomous rendezvous and docking. To address this need, Advanced Optical Systems, Inc., Orbital Sciences Corporation, and Marshall Space Flight Center have developed the Advanced Video Guidance Sensor (AVGS) under the auspices of the Demonstration of Autonomous Rendezvous Technology (DART) program. Given a cooperative target comprising several retro-reflectors, AVGS provides six-degree-of-freedom information at ranges of up to 300 meters for the DART target. It does so by imaging the target, then performing pattern recognition on the resulting image. Longer range operation is possible through different target geometries. Now that AVGS is being readied for its test flight in 2004, the question is: what next? Modifications can be made to AVGS, including different pattern recognition algorithms and changes to the retro-reflector targets, to make it more robust and accurate. AVGS could be coupled with other space-qualified sensors, such as a laser range-and-bearing finder, that would operate at longer ranges. Different target configurations, including the use of active targets, could result in significant miniaturization over the current AVGS package. We will discuss these and other possibilities for a next-generation docking sensor or sensor suite that involve AVGS.

Granade, Stephen R.↗
NASA NTRS2005

Long-duration Operation of 2-micron Coherent Doppler Lidar in Space

The reliability and lifetime of laser remote sensing systems that can operate autonomously over a sufficiently long period are mainly constrained by the laser diode arrays (LDAs) used for pumping their laser transmitters. The lifetime of a 2-micron coherent lidar operating in space is particularly of concern in lieu of required pump pulse duration of Thulium and Holmium solid state lasers (approx. 1msec) that are considerably longer than those of more widely used 1-micron lasers (< 0.2 msec). A factor of 5 to 10 times longer pulse duration can easily translate to over an order of magnitude shorter lifetime for a typical commercially available high-power 2-D array. Therefore, it is imperative to address the lifetime and reliability of LDAs for pumping 2-micron lasers by exploring all the potential options that significantly prolong their life meeting the required operational lifetime of space-based coherent Doppler lidars. The leading causes of sudden failure and premature degradation of LDAs are intrinsic semiconductor defects, optical facet breakdown resulting from excessive localized heating, and thermo-mechanical stresses due to the extreme thermal cycling of the laser active regions1-2. Long pulse operation grossly amplifies the impact of these failure/degradation causes, particularly the thermo-mechanical stresses due to pulse-to-pulse thermal cycling. Therefore, several experimental setups have been developed to investigate each of the failure mechanisms and causes of premature degradation in order to evaluate various package designs, define the best operating parameters, and to guide the technology advancement, leading to highly reliable and very long lifetime LDAs5. Several areas of improvement in the packaging and fabrication process of laser diodes have already been identified and efforts towards implementing these improvements are well underway. These efforts include the use of advanced high thermal conductivity materials for packaging of laser diode arrays and new fabrication techniques for mechanically attaching laser diode bars and submounts. But even using the existing LDAs, it may be possible to increase the lifetime by careful selection of the package type, number of bars per package and their pitch, operational temperature, and operating parameters such repetition rate, pulsewidth, and applied current. Obviously, the LDA specification and operational parameters will involve a system level trade analysis to ensure that the lidar instrument meets its performance objectives. One goal of this work is to enable such trade analysis by evaluating LDAs from different suppliers in different package types and quantifying their performance as a function of their operational parameters.

Amzajerdian, Farzin↗
NASA NTRS2006

Concept for a Large Scalable Space Telescope: In-Space Assembly

We present a conceptual design for a scalable (10-50 meter segmented filled-aperture) space observatory operating at UV-optical-near infrared wavelengths. This telescope is designed for assembly in space by robots, astronauts or a combination of the two, as envisioned in NASA s Vision for Space Exploration. Our operations concept for this-space telescope provides for assembly and check-out in an Earth Moon L2 (EML2) orbit, and transport to a Sun-Earth L2 (SEL2) orbit for science operations and routine servicing, with return to EML2 for major servicing. We have developed and analyzed initial designs for the optical, structural, thermal and attitude control systems for a 30-m aperture space telescope. We further describe how the separate components are packaged for launch by heavy lift vehicle(s) and the approach for the robot assembly of the telescope from these components.

Oegerle, W. R.↗
NASA NTRS2023

Pypromice: A Python Package for Processing Automated Weather Station Data

The pypromice Python package is for processing and handling observation datasets from automated weather stations (AWS). It is primarily aimed at users of AWS data from the Geological Survey of Denmark and Greenland (GEUS), which collects and distributes in situ weather station observations to the cryospheric science research community. Functionality in pypromice is primarily handled using two key open-source Python packages, xarray (Hoyer & Hamman, 2017) and pandas (The pandas development team, 2020). A defined processing workflow is included in pypromice for transforming original AWS observations (Level 0, L0) to a usable, CF-convention-compliant dataset (Level 3, L3) (Figure 1). Intermediary processing levels (L1,L2) refer to key stages in the workflow, namely the conversion of variables to physical measurements and variable filtering (L1), cross-variable corrections and user-defined data flagging and fixing (L2), and derived variables (L3). Information regarding the station configuration is needed to perform the processing, such as instrument calibration coefficients and station type (one-boom tripod or two-boom mast station design, for example), which are held in a toml configuration file. Two example configuration files are provided with pypromice , which are also used in the package’s unit tests. More detailed documentation of the AWS design, instrumentation, and processing steps are described in Fausto et al. (2021).

pypromice↗
DOE OSTI2024

Results from a multi-laboratory ocean metaproteomic intercomparison: effects of LC-MS acquisition and data analysis procedures

Metaproteomics is an increasingly popular methodology that provides information regarding the metabolic functions of specific microbial taxa and has potential for contributing to ocean ecology and biogeochemical studies. A blinded multi-laboratory intercomparison was conducted to assess comparability and reproducibility of taxonomic and functional results and their sensitivity to methodological variables. Euphotic zone samples from the Bermuda Atlantic Time-series Study (BATS) in the North Atlantic Ocean collected by in situ pumps and the autonomous underwater vehicle (AUV) Clio were distributed with a paired metagenome, and one-dimensional (1D) liquid chromatographic data-dependent acquisition mass spectrometry analysis was stipulated. Analysis of mass spectra from seven laboratories through a common bioinformatic pipeline identified a shared set of 1056 proteins from 1395 shared peptide constituents. Quantitative analyses showed good reproducibility: pairwise regressions of spectral counts between laboratories yielded R 2 values averaged 0.62±0.11, and a Sørensen similarity analysis of the top 1000 proteins revealed 70 %–80 % similarity between laboratory groups. Taxonomic and functional assignments showed good coherence between technical replicates and different laboratories. A bioinformatic intercomparison study, involving 10 laboratories using eight software packages, successfully identified thousands of peptides within the complex metaproteomic datasets, demonstrating the utility of these software tools for ocean metaproteomic research. Lessons learned and potential improvements in methods were described. Future efforts could examine reproducibility in deeper metaproteomes, examine accuracy in targeted absolute quantitation analyses, and develop standards for data output formats to improve data interoperability. Together, these results demonstrate the reproducibility of metaproteomic analyses and their suitability for microbial oceanography research, including integration into global-scale ocean surveys and ocean biogeochemical models.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

Uncertainty and Sensitivity Analysis Methods and Applications in the GDSA Framework (FY2021)

The Spent Fuel and Waste Science and Technology (SFWST) Campaign of the U.S. Department of Energy (DOE) Office of Nuclear Energy (NE), Office of Fuel Cycle Technology (FCT) is conducting research and development (R&D) on geologic disposal of spent nuclear fuel (SNF) and high-level nuclear waste (HLW). Two high priorities for SFWST disposal R&D are design concept development and disposal system modeling. These priorities are directly addressed in the SFWST Geologic Disposal Safety Assessment (GDSA) control account, which is charged with developing a geologic repository system modeling and analysis capability, and the associated software, GDSA Framework, for evaluating disposal system performance for nuclear waste in geologic media. GDSA Framework is supported by SFWST Campaign and its predecessor the Used Fuel Disposition (UFD) campaign. This report fulfills the GDSA Uncertainty and Sensitivity Analysis Methods work package (SF-21SN01030404) level 3 milestone, Uncertainty and Sensitivity Analysis Methods and Applications in GDSA Framework (FY2021) (M3SF-21SN010304042). It presents high level objectives and strategy for development of uncertainty and sensitivity analysis tools, demonstrates uncertainty quantification (UQ) and sensitivity analysis (SA) tools in GDSA Framework in FY21, and describes additional UQ/SA tools whose future implementation would enhance the UQ/SA capability of GDSA Framework. This work was closely coordinated with the other Sandia National Laboratory GDSA work packages: the GDSA Framework Development work package (SF-21SN01030405), the GDSA Repository Systems Analysis work package (SF-21SN01030406), and the GDSA PFLOTRAN Development work package (SF-21SN01030407). This report builds on developments reported in previous GDSA Framework milestones, particularly M3SF 20SN010304032.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

Machine-learning accelerated geometry optimization in molecular simulation

Geometry optimization is an important part of both computational materials and surface science because it is the path to finding ground state atomic structures and reaction pathways. These properties are used in the estimation of thermodynamic and kinetic properties of molecular and crystal structures. This process is slow at the quantum level of theory because it involves an iterative calculation of forces using quantum chemical codes such as density functional theory (DFT), which are computationally expensive and which limit the speed of the optimization algorithms. It would be highly advantageous to accelerate this process because then one could do either the same amount of work in less time or more work in the same time. Here, we provide a neural network (NN) ensemble based active learning method to accelerate the local geometry optimization for multiple configurations simultaneously. We illustrate the acceleration on several case studies including bare metal surfaces, surfaces with adsorbates, and nudged elastic band for two reactions. In all cases, the accelerated method requires fewer DFT calculations than the standard method. In addition, we provide an Atomic Simulation Environment (ASE)-optimizer Python package to make the usage of the NN ensemble active learning for geometry optimization easier.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

MolViewSpec: a Mol* extension for describing and sharing molecular visualizations

Data visualization is a pivotal component of a structural biologist’s arsenal. The Mol* Viewer makes molecular visualizations available to broader audiences via most web browsers. While Mol* provides a wide range of functionality, it has a steep learning curve and is only available via a JavaScript interface. To enhance the accessibility and usability of web-based molecular visualization, we introduce MolViewSpec (molstar.org/mol-view-spec), a standardized approach for defining molecular visualizations that decouples the definition of complex molecular scenes from their rendering. Scene definition can include references to commonly used structural, volumetric, and annotation data formats together with a description of how the data should be visualized and paired with optional annotations specifying colors, labels, measurements, and custom 3D geometries. Developed as an open standard, this solution paves the way for broader interoperability and support across different programming languages and molecular viewers, enabling more streamlined, standardized, and reproducible visual molecular analyses. MolViewSpec is freely available as a Mol* extension and a standalone Python package.

Midlik, Adam [European Bioinformatics Institute (U↗
NASA NTRS1975

Contamination control in hybrid microelectronic modules. Part 2: Selection and evaluation of coating materials

The selection, test, and evaluation of organic coating materials for contamination control in hybrid circuits is reported. The coatings were evaluated to determine their suitability for use as a conformal coating over the hybrid microcircuit (including chips and wire bonds) inside a hermetically sealed package. Evaluations included ease of coating application and repair and effect on thin film and thick film resistors, beam leads, wire bonds, transistor chips, and capacitor chips. The coatings were also tested for such properties as insulation resistance, voltage breakdown strength, and capability of immobilizing loose particles inside the packages. The selected coatings were found to be electrically, mechanically, and chemically compatible with all components and materials normally used in hybrid microcircuits.

Himmel, R. P.↗
NASA NTRS1978

Test-vehicle cycle programmer

Instrument reduces manpower needed for testing electric powered vehicles. Device has dual scale that allows operator to compare actual speed with preprogrammed test speed. Features include large meter, buzzer, packaging to allow ready interchange of memories with different profiles, small size, minimal current drain, and reverse supply voltage protection.

Lesco, D. J.↗
NASA NTRS1978

A standard load center converter power supply

A modular multiple-output Standard Load Center Converter (SLCC), developed for a wide range of space applications, is discussed, including its specifications, characteristics, electrical and mechanical designs, advanced heat removal techniques, and unique packaging concept. The converter can be tailored to meet specific requirements by simple selection of the proper transformer and feedback resistor networks.

Graves, J. R.↗
NASA NTRS1980

Vehicles testing of near-term batteries

Vehicles test results are reported for nickel-iron, nickel-zinc, and improved lead-acid batteries developed under the Near-Term Battery Program sponsored by the Department of Energy. The batteries have demonstrated a range improvement of up to 90% over current lead-acid batteries due to improved energy density and ampere-hour capacity, combined with relatively small weight and volume. However, the nickel-iron battery requires a substantial development effort in packaging the circulating electrolyte system and handling the generated hydrogen volume, while the nickel-zinc batteries tested suffer from short cycle life.

Conover, R. C.↗
NASA NTRS1982

Maypole (Hoop/Column) concept development program

The program is divided into six tasks: preliminary design and performance; materials development; advanced concepts; economic assessment; demonstration/verification models; and a 15 meter engineering model. All support the main objective of the program which is the technology development necessary to evaluate, design, manufacture, package, transport and deploy the Hoop/Column reflector by means of a ground-based test program. Progress for each task is reported.

Sullivan, M. R.↗