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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 397 records · Page 22

Improvements to the Search for Cosmic Dawn Using the Long Wavelength Array

We present recent improvements to the search for the global Cosmic Dawn signature using the Long Wavelength Array station located on the Sevilleta National Wildlife Refuge in New Mexico, USA (LWA{SV). These improvements are both in the methodology of the experiment and the hardware of the station. An improved observing strategy along with more sophisticated temperature calibration and foreground modelling schemes have led to improved residual RMS limits. A large improvement over previous work using LWA{SV is the use of a novel achromatic beamforming technique which has been developed for LWA{SV. We present results from an observing campaign which contains 29 days of observations between March 10th, 2021 and April 10th 2021. The reported residual RMS limits are 6 times above the amplitude of the potential signal reported by the Experiment to Detect the Global EoR Signature (EDGES) collaboration.

Christopher Dilullo↗

Granular Simulation of NEO Anchoring

NASA is interested in designing a spacecraft capable of visiting a Near Earth Object (NEO), performing experiments, and then returning safely. Certain periods of this mission will require the spacecraft to remain stationary relative to the NEO. Such situations require an anchoring mechanism that is compact, easy to deploy and upon mission completion, easily removed. The design philosophy used in the project relies on the simulation capability of a multibody dynamics physics engine. On Earth it is difficult to create low gravity conditions and testing in low gravity environments, whether artificial or in space is costly and therefore not feasible. Through simulation, gravity can be controlled with great accuracy, making it ideally suited to analyze the problem at hand. Using Chrono::Engine [1], a simulation package capable of utilizing massively parallel GPU hardware, several validation experiments will be performed. Once there is sufficient confidence, modeling of the NEO regolith interaction will begin after which the anchor tests will be performed and analyzed. The outcome of this task is a study with an analysis of several different anchor designs, along with a recommendation on which anchor is better suited to the task of anchoring. With the anchors tested against a range of parameters relating to soil, environment and anchor penetration angles/velocities on a NEO.

multibody dynamics↗

High-Performance Modeling and Simulation of Anchoring in Granular Media for NEO Applications

NASA is interested in designing a spacecraft capable of visiting a near-Earth object (NEO), performing experiments, and then returning safely. Certain periods of this mission would require the spacecraft to remain stationary relative to the NEO, in an environment characterized by very low gravity levels; such situations require an anchoring mechanism that is compact, easy to deploy, and upon mission completion, easy to remove. The design philosophy used in this task relies on the simulation capability of a high-performance multibody dynamics physics engine. On Earth, it is difficult to create low-gravity conditions, and testing in low-gravity environments, whether artificial or in space, can be costly and very difficult to achieve. Through simulation, the effect of gravity can be controlled with great accuracy, making it ideally suited to analyze the problem at hand. Using Chrono::Engine, a simulation pack age capable of utilizing massively parallel Graphic Processing Unit (GPU) hardware, several validation experiments were performed. Modeling of the regolith interaction has been carried out, after which the anchor penetration tests were performed and analyzed. The regolith was modeled by a granular medium composed of very large numbers of convex three-dimensional rigid bodies, subject to microgravity levels and interacting with each other with contact, friction, and cohesional forces. The multibody dynamics simulation approach used for simulating anchors penetrating a soil uses a differential variational inequality (DVI) methodology to solve the contact problem posed as a linear complementarity method (LCP). Implemented within a GPU processing environment, collision detection is greatly accelerated compared to traditional CPU (central processing unit)- based collision detection. Hence, systems of millions of particles interacting with complex dynamic systems can be efficiently analyzed, and design recommendations can be made in a much shorter time. The figure shows an example of this capability where the Brazil Nut problem is simulated: as the container full of granular material is vibrated, the large ball slowly moves upwards. This capability was expanded to account for anchors of different shapes and penetration velocities, interacting with granular soils.

Quadrelli, Marco B.↗

Directional Solidification of Bi-Sn on USMP-4

The experiments used MEPHISTO hardware to study the solidification and melting behavior of bismuth alloyed with 1 at% tin. Three samples, each approximately 900 mm long and 6mm in diameter, were used. A portion of each sample also included a 2 mm diameter growth capillary, to assist in the formation of a single grain. One sample provided the Seebeck voltage generated during melting and freezing processes. Another provided temperature data and Peltier pulsed demarcation of the interface shape for post flight analysis. The third sample provided resistance and growth velocity measurements, as well as additional thermal data. The third sample was also quenched at the end of the mission to preserve the composition of the liquid near the interface for post flight determination. A total of 450mm of directionally solidified samples were preserved for post mission structural and compositional characterization. Substantial differences were observed in the Seebeck signal between the ground-based experiments and the space-based experiments. The temperature gradient in the liquid for the ground-based experiments was significantly lower than the temperature gradient in the liquid for the space-based experiments.

Abbaschian, Reza↗

Two-Phase Flow in Filters and Orifices: In preparation for Measurements on ISS Packed Bed Reactor Experiment-Water Recovery Series (PBRE-WRS)

Understanding the hydrodynamics of adiabatic two-phase flows in packed bed reactors offers numerous benefits. It enables the optimization of chemical reactions rates and products, crucial for pharmaceuticals and energy production industries. Additionally, this understanding aids in designing more efficient and compact reactors, reducing space and resource requirements. Insights gained from studying such flows in microgravity contribute to advancements of space technologies and the enhancement of our capabilities for undertaking future long duration safe, and sustainable space exploration missions. The Packed Bed Reactor Experiment-Water Recovery Series (PBRE-WRS) is a flight experiment planned for operation on the Microgravity Science Glove box (MSG) facility of the International Space Station (ISS). The objective of the experiment is to validate hydrodynamic models at a range of gas and liquid flow rates. The microgravity environment allows for measurement and observation of aspects of fluid dynamics that are unique when compared to observations made in full or partial gravity environments. The experiment consists of testing two-phase flow hydrodynamics in three different filters, four (4) orifices and one check valve test articles. The experiment utilizes the hardware of the previously flown PBRE and PBRE-2 with packed beds of different packings materials and sizes. The fluid system of the PBRE-WRS consists of a nitrogen gas delivery and water delivery subsystems. The gas delivery subsystem can accommodate two ranges of gas flow rates, just as for the water delivery system. The nitrogen gas loop is open whereas the water loop is closed. Gas is separated from the water using a gas-liquid phase separator which is located in the water delivery module. Preliminary results from ground testing show the pressure drop increasing at different rates with the liquid and gas flow rates in the Brine filter. In this work, a detailed system description is presented along with a summary of results from ground performance testing of different test sections in an end-to-end preflight testing campaign.

Packed Bed Reactor Experiment↗

Scalable Hyperpolarized MRI Enabled by Ace‐SABRE of [1‐ 13 C]Pyruvate

Abstract Hyperpolarized (HP) MRI using [1– 13 C]pyruvate is emerging as a promising molecular imaging approach. Among hyperpolarization methods, Signal Amplification By Reversible Exchange (SABRE) is attractive because SABRE polarizes the substrates directly in room‐temperature solutions avoiding complex hardware. Most SABRE experiments have historically been performed in methanol, a relatively toxic and difficult‐to‐remove solvent. Here we demonstrate the use of a 80/20 acetone/water (A/W) solvent system (Ace‐SABRE) to provide hyperpolarized [1– 13 C]pyruvate with up to 17% polarization, then implement a solvent processing protocol to achieve injectable solutions retaining 74% of the initial polarization, and lastly we demonstrate HP in vivo spectroscopy and imaging using the Ace‐SABRE platform to showcase metabolic tracking in a hepatocellular carcinoma (HCC) tumor as well as HP‐MRI, both in direct comparison to dissolution dynamic nuclear polarization (d‐DNP) experiments. The Ace‐SABRE technique promises faster adoption of SABRE hyperpolarization in biological experiments, overall lowering the barriers to entry for HP‐NMR and HP‐MRI.

Chemistry↗

Simulators for quantum network modeling: A comprehensive review

Quantum network research is exploring new networking protocols, physics-based hardware and novel experiments to demonstrate how quantum distribution will work over large distances. Current work explores much of these concepts in simulations, that are developed to understand how quantum networking will be set up and researchers can experiment virtually. Exposing flaws in network designs, like unsustainable topologies, or develop protocols that efficiently utilize network resources, simulators can also help assess whether workloads are balanced across virtual machines in the network. However, much of these simulation models come without reliable verification methods, for testing performance in real deployments. Here, in this paper, we present a review of, to the best of our knowledge, currently used toolkits for modeling quantum networks. With these toolkits and standardized validation techniques, we can lay down the foundations for more accurate and reliable quantum network simulators.

97 MATHEMATICS AND COMPUTING↗

Evaluating a quantum-classical quantum Monte Carlo algorithm with Matchgate shadows

Solving the electronic structure problem of molecules and solids to high accuracy is a major challenge in quantum chemistry and condensed matter physics. The rapid emergence and development of quantum computers offer a promising route to systematically tackle this problem. Recent work by [Huggins et al ., Nature (London) 603 , 416 (2022)] proposed a hybrid quantum-classical quantum Monte Carlo (QC-QMC) algorithm using Clifford shadows to determine the ground state of a Fermionic Hamiltonian. This approach displayed inherent noise resilience and the potential for improved accuracy compared to its purely classical counterpart. Nevertheless, the use of Clifford shadows introduces an exponentially scaling postprocessing cost. In this work, we investigate an improved QC-QMC scheme utilizing the recently developed Matchgate shadows technique [Commun. Math. Phys. 404 , 629 (2023)], which removes the aforementioned exponential bottleneck. We observe from experiments on quantum hardware that the use of Matchgate shadows in QC-QMC is inherently noise robust. We show that this noise resilience has a more subtle origin than in the case of Clifford shadows. Nevertheless, we find that classical postprocessing, while asymptotically efficient, requires hours of runtime on thousands of classical CPUs for even the smallest chemical systems, presenting a major challenge to the scalability of the algorithm.

Monte Carlo methods↗

Development of message passing-based graph convolutional networks for classifying cancer pathology reports

Abstract Background Applying graph convolutional networks (GCN) to the classification of free-form natural language texts leveraged by graph-of-words features (TextGCN) was studied and confirmed to be an effective means of describing complex natural language texts. However, the text classification models based on the TextGCN possess weaknesses in terms of memory consumption and model dissemination and distribution. In this paper, we present a fast message passing network (FastMPN), implementing a GCN with message passing architecture that provides versatility and flexibility by allowing trainable node embedding and edge weights, helping the GCN model find the better solution. We applied the FastMPN model to the task of clinical information extraction from cancer pathology reports, extracting the following six properties: main site, subsite, laterality, histology, behavior, and grade. Results We evaluated the clinical task performance of the FastMPN models in terms of micro- and macro-averaged F1 scores. A comparison was performed with the multi-task convolutional neural network (MT-CNN) model. Results show that the FastMPN model is equivalent to or better than the MT-CNN. Conclusions Our implementation revealed that our FastMPN model, which is based on the PyTorch platform, can train a large corpus (667,290 training samples) with 202,373 unique words in less than 3 minutes per epoch using one NVIDIA V100 hardware accelerator. Our experiments demonstrated that using this implementation, the clinical task performance scores of information extraction related to tumors from cancer pathology reports were highly competitive.

59 BASIC BIOLOGICAL SCIENCES↗

Shuttle/Agena study. Annex B: Catalog of existing flight equipment

The Agena space tug design was based on the requirements of representative reference missions, the use of existing hardware, and the experience gained from more than 300 Agena flights. To provide a convenient reference for understanding the Agena tug design selection or for evaluating alternative concepts, this catalog of existing flight equipment was prepared. Equipment descriptions are grouped by Agena subsystem, as follows: spaceframe; propulsion; electrical; guidance and flight controls; and telemetry, tracking, and command. These systems, most of which have been flight qualified on prior Agena programs, permit specialized mission requirements to be satisfied without sacrificing cost or reliability.

Source record↗

Investigation of KC-135 flight samples solidified in near-zero gravity

An analysis was conducted of three KC-135 flight samples that had been solidified in near-zero gravity. These samples had been generated during near-zero gravity testing of M553 experiment Skylab flight hardware. The samples evaluated were all Star-J Satellite, a cobalt base alloy. The analytical procedures (optical microscopy, scanning electron microscopy, electron microprobe, X-ray diffraction, differential scanning calorimetry, and microhardness) to be use on the Skylab flight samples were optimized and the analytical results are presented.

Larson, D., Jr.↗

Apollo 17 Mission Report

Operational and engineering aspects of the Apollo 17 mission are outlined. The vehicle configuration was similar to those of Apollo 15 and 16. There were significant differences in the science payload for Apollo 17 and spacecraft hardware differences and experiment equipment are described. The mission achieved a landing in the Taurus-Littrow region of the moon and returned samples of the pre-Imbrium highlands and young craters.

MIssion Evaluation Team↗

Estimation in satellite control.

The use of estimators or observers is discussed as applied to satellite attitude control and the control of drag-free satellites. The practical problems of implementation are discussed, and the relative advantages of full and reduced state estimators are compared, particularly in terms of their effectiveness and bandwidth as filters. Three applications are used to illustrate the principles. They are: (1) a reaction wheel control system, (2) a spinning attitude control system, and (3) a drag-free satellite translational control system. Fixed estimator gains are shown to be adequate for these (and many other) applications. Our experience in the hardware realization of estimators has led to categorize the error sources in terms of those that improve with increased estimator gains and those that get worse with increased estimator gains.

Debra, D. B.↗

Systems engineering at the Jet Propulsion Laboratory.

Work at the JPL in systems engineering is surveyed with the emphasis on practical experience with large hardware and software systems. Systems concepts in lunar and planetary projects, in the Morgantown project, and in the Urban Health Systems Task are discussed. Goal definition, problem statement, objective and criteria development, and synthesis, analysis, selection and implementation of systems are considered as successive steps in the optimization of the overall system.-

Pickering, W. H.↗

Reliability history of the Apollo guidance computer

The Apollo guidance computer was designed to provide the computation necessary for guidance, navigation and control of the command module and the lunar landing module of the Apollo spacecraft. The computer was designed using the technology of the early 1960's and the production was completed by 1969. During the development, production, and operational phase of the program, the computer has accumulated a very interesting history which is valuable for evaluating the technology, production methods, system integration, and the reliability of the hardware. The operational experience in the Apollo guidance systems includes 17 computers which flew missions and another 26 flight type computers which are still in various phases of prelaunch activity including storage, system checkout, prelaunch spacecraft checkout, etc. These computers were manufactured and maintained under very strict quality control procedures with requirements for reporting and analyzing all indications of failure. Probably no other computer or electronic equipment with equivalent complexity has been as well documented and monitored. Since it has demonstrated a unique reliability history, it is important to evaluate the techniques and methods which have contributed to the high reliability of this computer.

Hall, E. C.↗

Space tug spacecraft/module exchanger (on-orbit servicer)

On-orbit exchange of spacecraft modules containing experiment or subsystem hardware or consumables performed at goesynchronous altitudes with the space tug and at lower altitudes with the shuttle is described. One promising concept for such a tug-mounted spacecraft module exchange is the McDonnell Douglas Direct-Access Servicer. This servicer can also be used in low orbit, mounted on the shuttle. In this concept, push-pull injector/retractor devices are combined with a rotating indexer to provide a minimum-complexity mechanism with a high capacity for coincident exchange of many modules.

Runge, F. C.↗

Conceptual design for spacelab two-phase flow experiments

KC-135 aircraft tests confirmed the gravity sensitivity of two phase flow correlations. The prime component of the apparatus is a 1.5 cm dia by 90 cm fused quartz tube test section selected for visual observation. The water-cabin air system with water recycle was a clear choice for a flow regime-pressure drop test since it was used satisfactorily on KC-135 tests. Freon-11 with either overboard dump or with liquid-recycle will be used for the heat transfer test. The two experiments use common hardware. The experimental plan covers 120 data points in six hours with mass velocities from 10 to 640 kg/sec-sq m and qualities 0.01 to 0.64. The apparatus with pump, separator, storage tank and controls is mounted in a double spacelab rack. Supporting hardware, procedures, measured variables and program costs are defined.

Bradshaw, R. D.↗