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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 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Sample glue layer investigation and mitigation for laser induced prompt impulse experiments

Understanding longer timescale material reactions under dynamic stress loading is critical for applications in materials engineering, shock physics, and planetary science. Prompt impulse experiments generate lower pressures since the ablator—the material first removed by the laser—is thicker and farther from the diagnostic plane, capturing aggregate material responses from the initial shock wave, rarefaction waves, and later time effects. This complexity demands thorough material characterization and simulation support. Since traditional sample construction is specific to supported shock experiments, designing prompt impulse experiments requires reconsideration around target design and sample engineering. Here, we present sample preparation techniques, experimental investigations, and theoretical simulations to investigate glue layer impacts, aiming to standardize samples for consistent data at lower laser fluences. We find that glue layers <30 μm have a minimal impact on peak velocity and pulse shape. The peak velocity scales linearly with glue layer thickness until a glue layer of 75 μm. For glue layers >75 μm, the peak velocity no longer scales with thickness; however, the pulse shape continues to degrade as described by simulations.

Lasers↗
NASA NTRS1975

Research study on stabilization and control: Modern sampled-data control theory. Design of the large space telescope system

Conditions of self-sustained oscillations in a two-axis model of the nonlinear LST system are studied. The describing function of the CMG frictional nonlinearity of the LST system is used for the analysis, as well as continuous-data and discrete-data models of the simplified LST control system. A numerical-iterative method is described for the analysis of the two-axis system. Approximation methods and the direct plotting of the stability equation are implemented in the study. It is shown that although the dynamics of the two axes are identical, the amplitudes of self-sustained oscillations in the two axes may in principle be different. Analysis shows that the LST systems are of equal amplitudes but with 180-degree phase shift.

Kuo, B. C.↗
NASA NTRS1982

Navigation system design for a Halley sample return mission

A ballistic sample return mission to Comet Halley was recently considered by the United States. This paper describes the navigation system and the navigation strategy which would have been employed in such a mission, assuming a launch in August of 1985, an arrival at the comet in March of 1986, and a return to earth in August of 1989. Estimates of spacecraft comet- and earth-relative orbit determination accuracies are presented as functions of time. Target-relative delivery accuracies for the spacecraft and associated trajectory correction maneuver requirements are presented also.

Wood, L. J.↗
NASA NTRS1988

How successful were the lunar sampling tools: Implications for sampling Mars

Like the Mars Sample Return endeavor, the Apollo lunar-sample program began with definition of strategy for sample collection and of scientific requirements for sampling hardware design. Several lessons can be illustrated by specific tools. The evolution of drive tubes from narrow 2 cm diameter, thick-walled tubes (used on Apollo 11, 12 and 14) to 4 cm diameter, thin-walled tubes used on Apollo 15, 16, and 17) as an example of the improvements made possible during multiple missions. The original Apollo 11 drive tube was designed to work in fluffy soil; thus, only 50 percent of the relatively dense lunar soil was recovered, and the core was distorted. The final configuration resulted in nearly 100 pct recovery with little distortion. The surface samplers (Contact Soil Sampling Devices) were designed to collect the upper 100 micrometer or the upper 1 mm of soil. It was over 2 years after the mission before these particularly specific samplers were opened because interest in them waned. Both core tubes and surface samplers were difficult to open in the laboratory. The Apollo Lunar Sample Return Containers (ALSRCs) were constructed with one indium and 2 Viton seals. They were closed on the lunar surface. Interior container pressures measured upon return to the laboratory indicate that these seals were not reliable in the lunar environment. Also, choice of indium as a sealing material interfered with siderophile analyses of samples.

Allton, J. H.↗
DOE OSTI2024

A Novel Concentrating Solar Weathering Apparatus for Experimental Validation of Multi-Modal Degradation Models

High-performance coatings for Concentrating Solar Power (CSP) receivers are subjected to remarkable environmental stressors during normal operations. Applied to the receiver tubes, these coatings serve to maximize the solar absorptivity of the receiver, transferring as much heat as possible from the solar collectors into the heat-transfer fluid (HTF). The lifecycle of these coatings is not well-defined, and the harsh operational conditions make them difficult to test. NREL has designed, built, and tested an apparatus to expose these samples to design levels of environmental stress and well beyond, into accelerated and destructive conditions. The chamber is actively cooled, monitored, and has the capability to supply humidification for cycling tests, allowing us to test multi-modal degradation and failure conditions at high temperature, high flux, and high humidity conditions. These conditions can catalyze high-temperature oxidation, mechanical degradation, and other modes of absorptivity loss seen in selective solar receiver coatings. The experimental data can feed lifecycle models for expensive and necessarily resilient materials, offering insights to aid maintenance schedules, technoeconomic analysis, and material industry performance benchmarks. This presentation will demonstrate the apparatus design and performance, as well as initial results for aging on a selective receiver coating.

14 SOLAR ENERGY↗
NASA NTRS2009

Fused Bead Analysis of Diogenite Meteorites

Bulk rock chemistry is an essential dataset in meteoritics and planetary science [1]. A common method used to obtain the bulk chemistry of meteorites is ICP-MS. While the accuracy, precision and low detection limits of this process are advantageous [2], the sample size used for analysis (approx.70 mg) can be a problem in a field where small and finite samples are the norm. Fused bead analysis is another bulk rock analytical technique that has been used in meteoritics [3]. This technique involves forming a glass bead from ~10 mg of sample and measuring its chemistry using a defocused beam on a microprobe. Though the ICP-MS has lower detection limits than the microprobe, the fused bead method destroys a much smaller sample of the meteorite. Fused bead analysis was initially designed for samples with near-eutectic compositions and low viscosities. Melts generated of this type homogenize at relatively low temperatures and produce primary melts near the sample s bulk composition [3]. The application of fused bead analysis to samples with noneutectic melt compositions has not been validated. The purpose of this study is to test if fused bead analysis can accurately determine the bulk rock chemistry of non-eutectic melt composition meteorites. To determine this, we conduct two examinations of the fused bead. First, we compare ICP-MS and fused bead results of the same samples using statistical analysis. Secondly, we inspect the beads for the presence of crystals and chemical heterogeneity. The presence of either of these would indicate incomplete melting and quenching of the bead.

Mittlefehldt, D.W.↗
NASA NTRS1970

A Study of the Electrotransport in Thin Films: An Advanced Method for the Study of Electrotransport in Thin Films Using Electrical Resistance Measurements

To date, very little is understood about electrotransport in thin films. One reason for this is the lack of methods in which electromigration can be adequately monitored dynamically. In this thesis, a new nondestructive method for the study of the electrotransport phenomenon in thin aluminum films is presented. This method makes use of electrical resistance measurements of various regions along the test sample to monitor changes in resistance resulting from electromigration. The advantage of this method is that resistance changes can be observed long before void formation can be seen using standard microscopy methods. In order to achieve the best efficiency using this method, special consideration must be given to the design of the sample. Design problems and their respective solutions are given. The results of the electrical resistance measurements are interpreted by means of photographs taken with an scanning electron microscope. The increase in resistance of the aluminum samples is interpreted to be due to void formation. The expected decrease in resistance near the anode was never observed. It is shown that mass accumulation takes on the form of hillocks and whiskers on the surface of the aluminum film, which does not contribute appreciably to conductivity.

Hummel, R. E.↗
DOE OSTI2022

A Subspace-Inclusive Sampling Method for the Computational Design of Compositionally Graded Alloys

Abstract Compositionally graded alloys, a subclass of functionally graded materials (FGMs), utilize localized variations in composition with a single metal part to achieve higher performance than traditional single material parts. In previous work [Kirk, T., Galvan, E., Malak, R., and Arroyave, R., 2018, “Computational Design of Gradient Paths in Additively Manufactured Functionally Graded Materials,” J. Mech. Des., 140, p. 111410. 10.1115/1.4040816], the authors presented a computational design methodology that avoids common issues which limit a gradient alloy’s feasibility, such as deleterious phases, and optimizes for performance objectives. However, the previous methodology only samples the interior of a composition space, meaning designed gradients must include all elements in the space throughout the gradient. Because even small amounts of additional alloying elements can introduce new deleterious phases, this characteristic often neglects potentially simpler solutions to otherwise unsolvable problems and, consequently, discourages the addition of new elements to the state space. The present work improves upon the previous methodology by introducing a sampling method that includes subspaces with fewer elements in the design search. The new method samples within an artificially expanded form of the state space and projects samples outside the true region to the nearest true subspace. This method is evaluated first by observing the sample distribution in each subspace of a 3D, 4D, and 5D state space. Next, a parametric study in a synthetic 3D problem compares the performance of the new sampling scheme to the previous methodology. Lastly, the updated methodology is applied to design a gradient from stainless steel to equiatomic NiTi that has practical uses such as embedded shape memory actuation and for which the previous methodology fails to find a feasible path.

Engineering↗
NASA NTRS1972

Superconducting rock magnetometer system

A three axis magnetometer system intended for use in the magnetic measurement of lunar rock samples was designed, fabricated and delivered to NASA Manned Spacecraft Center. The system has a four inch diameter room temperature sample access region and is fitted with three orthogonal magnetic field sensors enclosing this region. Two superconducting magnetic shields are incorporated, which are designed to eliminate external magnetic noise from the sense coils. A superconducting solenoid is mounted coaxially with the sample region and this provides axial magnetic fields up to 1,000 gauss. The system was designed for measuring magnetic moments of geophysical samples, especially remanent moments of lunar samples. The sensitivity of the system in all three axes is about 2 x 10 to the -7th power EMU square root HZ peak to peak, measured in the 0 to 1 Hz bandwidth.

Source record↗
NASA NTRS2017

Development of NASA's Sample Cartridge Assembly: Summary of GEDS Design, Development Testing, and Thermal Analyses

Outline: Background of ISS (International Space Station) Material Science Research Rack; NASA SCA (Sample Cartridge Assembly) Design; GEDS (Gravitational Effects in Distortion in Sintering) Experiment Ampoule Design; Development Testing Summary; Thermal Modeling and Analysis. Summary: GEDS design development challenging (GEDS Ampoule design developed through MUGS (Microgravity) testing; Short duration transient sample processing; Unable to measure sample temperatures); MUGS Development testing used to gather data (Actual LGF (Low Gradient Furnace)-like furnace response; Provided sample for sintering evaluation); Transient thermal model integral to successful GEDS experiment (Development testing provided furnace response; PI (Performance Indicator) evaluation of sintering anchored model evaluation of processing durations; Thermal transient model used to determine flight SCA sample processing profiles).

O'Connor, Brian↗
NASA NTRS2019

Initial Developments of a Low Drag Variable Depth Acoustic Liner

The purpose of this study is to assess the acoustic performance and relative drag of a new type of variable depth liner containing pairs of resonators coupled together by shared inlet volumes just below the facesheet. This type of liner has the potential to achieve a targeted impedance with fewer openings in the facesheet, and therefore less drag, than previous designs. To better understand the limitations of the concept, three sets of samples were designed and tested in the NASA Langley normal incidence and grazing flow impedance tubes. Each set of samples consisted of a baseline variable depth liner with straight chambers, and a prototype liner with shared inlet volumes. Measurements conducted in both the normal incidence and grazing flow impedance tubes confirm that the prototype liner can achieve the same impedance as the baseline variable depth liner at discrete frequencies with 50% less open area. This results in a 75% reduction in the drag penalty relative to the baseline design. The proposed concept is not, however, able to achieve a flat, broadband impedance as effectively as the baseline liner. So, while the proposed concept is well suited for multitonal design metrics, tradeoffs must be made between liner drag and acoustic performance when broadband attenuation is required.

Schiller, Noah H.↗
DOE OSTI2025

Physical Testing of The PSEC5 ASIC

The PSEC5 ASIC is a high-speed waveform sampling chip designed for ultra-fast timing detectors, offering up to 40 GSPS sampling with 10-bit resolution. This makes it well-suited for applications requiring fine time resolution, such as MCPs and LGADs. This work focuses on the physical testing and validation of the chip s internal clocking and SPI-controlled registers. Testing began with inspection of schematics and the prototype to identify and resolve design issues. Then, custom firmware was developed for an Arduino controller to interface with the chip via SPI, enabling read and write access to key control registers. Results confirm that the VCO operates between ~3.2 4.0 GHz and remains stable under non-VCOVDD fluctuations. The Division Ratio register enables frequency division by known factors (256, 128, 64, etc.), indicating a pre-division frequency of 3.2 GHz when the digital band is unmodified. While most registers responded correctly, some issues were observed, including unexpected current draw and unstable discriminator behavior. Overall, the chip shows promising functionality, but further work is needed to understand the state of the read only registers and address the existing issues. Continued testing and firmware development will be critical to ensuring reliable integration into detector systems.

Fahey, Alexander [Unlisted, US]↗
NASA NTRS1983

Terminal area automatic navigation, guidance and control research using the Microwave Landing System (MLS). Part 5: Design and development of a Digital Integrated Automatic Landing System (DIALS) for steep final approach using modern control techniques

The design and development of a 3-D Digital Integrated Automatic Landing System (DIALS) for the Terminal Configured Vehicle (TCV) Research Aircraft, a B-737-100 is described. The system was designed using sampled data Linear Quadratic Gaussian (LOG) methods, resulting in a direct digital design with a modern control structure which consists of a Kalman filter followed by a control gain matrix, all operating at 10 Hz. DIALS uses Microwave Landing System (MLS) position, body-mounted accelerometers, as well as on-board sensors usually available on commercial aircraft, but does not use inertial platforms. The phases of the final approach considered are the localizer and glideslope capture which may be performed simultaneously, localizer and steep glideslope track or hold, crab/decrab and flare to touchdown. DIALS captures, tracks and flares from steep glideslopes ranging from 2.5 deg to 5.5 deg, selected prior to glideslope capture. Digital Integrated Automatic Landing System is the first modern control design automatic landing system successfully flight tested. The results of an initial nonlinear simulation are presented here.

Halyo, N.↗
NASA NTRS2014

Development of Genesis Solar Wind Sample Cleanliness Assessment: Initial Report on Sample 60341 Optical Imagery and Elemental Mapping

Since 2005 the Genesis science team has experimented with techniques for removing the contaminant particles and films from the collection surface of the Genesis fragments. A subset of ~40 samples have been designated as "cleaning matrix" samples. These are small samples to which various cleaning approaches are applied and then cleanliness is assessed optically, by TRXRF, SEM, ToF-SIMS, XPS, ellipsometry or other means [1-9]. Most of these sam-ples remain available for allocation, with cleanliness assessment data. This assessment allows evaluation of various cleaning techniques and handling or analytical effects. Cleaning techniques investigated by the Genesis community include acid/base etching, acetate replica peels, ion beam, and CO2 snow jet cleaning [10-16]. JSC provides surface cleaning using UV ozone exposure and ultra-pure water (UPW) [17-20]. The UPW rinse is commonly used to clean samples for handling debris between processing by different researchers. Optical microscopic images of the sample taken before and after UPW cleaning show what has been added or removed during the cleaning process.

Gonzalez, C. P.↗
NASA NTRS2017

Automated Sensitivity Analysis of Interplanetary Trajectories for Optimal Mission Design

This work describes a suite of Python tools known as the Python EMTG Automated Trade Study Application (PEATSA). PEATSA was written to automate the operation of trajectory optimization software, simplify the process of performing sensitivity analysis, and was ultimately found to out-perform a human trajectory designer in unexpected ways. These benefits will be discussed and demonstrated on sample mission designs.

trajectory design↗