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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS2021

Hypervelocity Impact Study for Migration from Kevlar® KM2® 705 to KM2® Plus 775: Material Property Measurement and Evaluation as a Ballistic Enhancement in Whipple Shields

Dupont™, the manufacturer of Kevlar®, has begun migrating from KM2® to KM2® Plus for ballistic textiles. Kevlar® KM2® has become an essential element of numerous meteoroid and orbital debris (MMOD) shield systems primarily as a multi-layer insulation (MLI) enhancement, and as such, the migration has implications for numerous system level risk assessments for future vehicles that will need to use the newer KM2® Plus fiber system. While the chemical makeup of the two fabrics are identical, differences in processing have yielded higher tenacities and toughness for the KM2® Plus system. To address this migration, the Hypervelocity Impact Technology (HVIT) group in NASA Exploration Sciences at Johnson Space Center (JSC) has worked with the NASA Engineering and Safety Center (NESC), the Multi-Purpose Crew Vehicle (MPCV) and the MPCV European Service Module (MPCV-ESM) group of the European Space Agency (ESA) with its contractors Airbus and Thales Alenia Space-Italy (TAS-I) to study how KM2® Plus in the woven form of 850 denier 775 compares with KM2® in the woven form of 850 denier 705. The two forms of Kevlar® fabrics have been compared by direct-impact with a known mass and as the rear wall in Whipple shields using the two-stage, light-gas-gun at the Remote Hypervelocity Test Laboratory (RHTL) of NASA JSC White Sands Test Facility (WSTF). From these examinations, it has been found that KM2® Plus does in fact improve the ballistic performance as a ballistic enhancement of MLI with an estimated improvement of 9.5±6.1% between the two fabrics, and on a mass basis, the estimated mass of KM2® Plus 775 is 3.6±0.7% lighter than KM2 705, which means the mass performance improvement is even higher.

Joshua E Miller↗
NASA NTRS2016

Characterization of Candidate Materials for Remote Recession Measurements of Ablative Heat Shield Materials

A method of remotely measuring surface recession of a material sample in a plasma flow through emission spectroscopy of the post shock layer was characterized through experiments in the NASA Langley HYMETS arc jet facility. Different methods for delivering the seed products into the Phenolic Impregnated Carbon Ablator (PICA) material samples were investigated. Three samples were produced by seeding the PICA material with combinations of Al, Si, HfO2, VB2, Al2O3, SiO2, TiC, HfC, NaCl, and MgCl2 through infusing seed materials into a core of PICA, or through encapsulating seed material in an epoxy disk, mechanically bonding the disk to a PICA sample. The PICA samples seeded with the candidate tracers were then tested at surface temperatures near 2400 K under low pressure air plasma. The emission of Al, Ti, V, Na, and Mg in the post-shock layer was observed in the UV with a high resolution imaging spectrometer viewing the whole stagnation line from the side, and from UV to NIR with a fiber-coupled miniaturized spectrometer observing the sample surface in the wavelength range from 200 nm to 1,100 nm from the front through a collimator. Al, Na, and Mg were found to be emitting in the post-shock spectra even before the recession reached the seeding depth - therefore possibly characterizing the pyrolysis process rather than the recession itself. The appearance of Ti and V emission in the spectra was well correlated with the actual recession which was monitored through a video of the front surface of the sample. The applicability of a seed material as an indicator for recession appears to be related to the melting temperature of the seed material. Future parametric studies will be carried out in low power plasma facilities at the University of Kentucky.

Butler, Bradley D.↗
NASA NTRS1986

Measuring Acoustic-Radiation Stresses in Materials

System measures nonlinearity parameters of materials. Uses static strain generated by acoustic wave propagating in material. Since static strain is effectively "dc" component of waveform distortion, problems associated with phase-cancellation artifacts disappear. Further, sign of nonlinearity parameter obtained by simple inspection of measured signal polarity. These features make this system very amenable to use in field. System expected to become standard for acoustic-radiation-stress measurements for solids and liquids and for characterization of material properties related to strength and residual or applied stresses. Also expected to become standard for transducer calibration.

Cantrell, John H.↗
NASA NTRS1999

Space Portable Spectroreflectometer (SPSR) Investigation on Mir Space Station

Degradation of thermal control surface properties results from the synergistic effects of the space environment's interaction with materials. This includes the natural space environment and the contamination environment produced by the spacecraft itself. Past flight experiments have utilized small witness samples which were recovered for post flight analysis on the ground. However, reintroduction into an oxygen atmosphere can, in itself, cause a change in the properties of the material being studied. Space based measurements using video cameras were not quantifiable. Very limited experiments have previously measured material properties in-situ on a spacecraft but only using small prepared witness samples with minimal exposure to space. The only way to really determine the properties of actual spacecraft surfaces after an extended exposure to the space environment is to measure them directly, in space. The SPSR provides this capability to measure the most important thermal property which can change in the space environment, the solar absorptivity. The Mir space station provides an excellent opportunity for such experiments due to the long exposure that some of the modules have experienced. Measurements from different modules would have provided an opportunity to determine the effect of various exposure time in orbit and under different contamination environments. Due to other pressing issues only one site was measured using the SPSR.

Carruth, M. Ralph, Jr.↗
DOE OSTI2024

Validation of galvanomagnetic and thermomagnetic transport measurements using Standard Reference Material 3451

In the “method of four coefficients,” electrical resistivity (ρ), Seebeck coefficient (S), Hall coefficient (RH), and Nernst coefficient (Q) of a material are measured and typically fit or modeled with theoretical expressions based on Boltzmann transport theory to glean experimental insights into features of electronic structure and/or charge carrier scattering mechanisms in materials. Although well-defined and readily available reference materials exist for validating measurements of ρ and S, none currently exists for R H or Q. We show that measurements of all four transport coefficients—ρ, S, R H , and Q—can be validated using a single reference sample, namely, the low-temperature Seebeck coefficient Standard Reference Material® (SRM) 3451 (composition Bi 2 Te 3+x ) available from the National Institute for Standards and Technology (NIST) without the need for inter-laboratory sample exchange. Here, R H and Q data for NIST SRM 3451 reported here for the temperature range 80–400 K complement the data already available for ρ and S and will therefore be of interest to researchers desiring to validate new or existing galvanomagnetic and thermomagnetic transport properties measurement systems.

47 OTHER INSTRUMENTATION↗
NASA NTRS1983

Space Station needs, attributes and architectural options. Volume 2, book 1, part 2, task 1: Mission requirements

Mission areas analyzed for input to the baseline mission model include: (1) commercial materials processing, including representative missions for producing metallurgical, chemical and biological products; (2) commercial Earth observation, represented by a typical carry-on mission amenable to commercialization; (3) solar terrestrial and resource observations including missions in geoscience and scientific land observation; (4) global environment, including representative missions in meteorology, climatology, ocean science, and atmospheric science; (5) materials science, including missions for measuring material properties, studying chemical reactions and utilizing the high vacuum-pumping capacity of space; and (6) life sciences with experiments in biomedicine and animal and plant biology.

Source record↗
NASA NTRS2017

Cryogenic Thermal Conductivity Measurements on Candidate Materials for Space Missions

Spacecraft and instruments on space missions are built using a wide variety of carefully-chosen materials. In addition to having mechanical properties appropriate for surviving the launch environment, these materials generally must have thermal conductivity values which meet specific requirements in their operating temperature ranges. Space missions commonly propose to include materials for which the thermal conductivity is not well known at cryogenic temperatures. We developed a test facility in 2004 at NASAs Goddard Space Flight Center to measure material thermal conductivity at temperatures between 4 and 300 Kelvin, and we have characterized many candidate materials since then. The measurement technique is not extremely complex, but proper care to details of the setup, data acquisition and data reduction is necessary for high precision and accuracy. We describe the thermal conductivity measurement process and present results for several materials.

thermal conductivity↗
NASA NTRSDate not supplied

High Temperature Material Property Data and Challenges to Thermal Process Model Predictions and In-Situ/Ex-Situ Measurements for Metallic Additive Manufacturing

Understanding and predicting performance properties of parts produced by metallic additive manufacturing has improved significantly over the past decade; however, difficult to measure material properties and process outcomes continue to be challenges. The qualification or certification of aerospace parts require extensive measures to quantify variable part properties in order to buy down the risk of component failure. The variability, inherent to the additive manufacturing, process adds unwanted uncertainty in the production of load critical structural components. Process modeling has proven valuable in providing predictions and context for understanding outcomes of the additive manufacturing process; however, these physically informed process models require material properties at temperatures that are difficult to measure and rarely available. Further, calibrating or validating such models is difficult because the process itself is challenging to measure. This talk will explore some of the challenges resulting from difficult to acquire input data by relating thermal process model predictions to in-situ and ex-situ optical microscopy measurements.

Process Model↗
DOE OSTI2020

Chapter 15: Summary and Outlook

In the various chapters of this book, numerous characterization techniques are presented that can be applied to thin-film solar cells to determine (micro)structural, compositional, electrical, and optoelectronic properties. What has yet to be more fully elucidated is to what extent these characterization techniques can be combined, in a correlative way, to enhance the information gathered on materials and devices. Indeed, it is valuable to consider combining techniques to verify the relevance of the measured materials properties or to obtain them on different length scales-to compare surface with bulk properties, or to correlate structure and composition of materials with electrical and optoelectronic properties.

41 EE - Solar Energy Technologies Office (EE-4S)↗
NASA NTRS2014

Development of New Dielectric NDE Techniques for Spaceflight Materials

Dielectric Spectroscopy is a relatively new technique for non-destructively measuring material properties. The goal for this project is to extend the use of state-of-the-art dielectric spectroscopy systems to measure the spectra of spaceflight materials and develop non-destructive evaluation (NDE) sensors based on dielectric material properties. This work may lead to a new class of material density, moisture, temperature, and defect sensors providing structural integrity and health measurements for future spacecraft and launch structures.

Project↗
NASA NTRS1978

Reflectance measurements of lunar materials in the vacuum ultraviolet

The spectral reflectances of materials have been measured in the vacuum ultraviolet region of the spectrum for possible planetary compositional remote-sensing applications. These materials, which include lunar and terrestrial silicate rocks and minerals, have one or more characteristic absorption peaks between about 8 and 13 eV. The peaks are visible in the spectra of powders and rough surfaces as well as polished surfaces. In lunar samples the most prominent peaks are at 10.25 eV, due to augite, and at 9.0 eV, due to anorthite. Spectra of lunar soils have minima between 6 eV (0.20 micron) and 8 eV (0.16 micron) depending on composition. Soils that have high reflectances in the visible have low reflectances in the VUV. The pyroxene content of the soils results in reflectance maxima at about 10 eV (0.12 micron). Peaks due to olivine and augite can be identified in the spectra of meteorites.

Hapke, B. W.↗
NASA NTRS1993

New Eddy Current Probe for Thickness Gauging of Conductive Materials

The accurate measure of material thickness is important for many non-destructive evaluation applications. Factors such as corrosion damage can jeopardize structural integrity through material thinning and process control considerations often mandate strict limits on material dimensions. Access to the material under test can be limited to a single side and large areas may need to be examined in a small time period. In an effort to enhance the effectiveness of material thickness measurements a flux focusing eddy current probe has been developed at NASA Langley Research Center. The probe provides an accurate measure of the thickness of conducting materials from a single sided measurement. It is straight forward to use and can be easily automated for production line testing. The probe also requires only minimal instrumentation and power so that extremely portable units can be manufactured at a low cost. This new eddy current probe has been used to accurately measure the thickness of aluminum alloy plates with a resolution of greater than 0.001 in. (25 microns). Simulated corrosion damage has also been detected on both single layer and multi-layer samples. The present work will explain the output voltage dependence of the device as a function of material thickness and present experimental results for thickness gauging and corrosion detection.

Wincheski, Buzz↗
NASA NTRS1983

Field Measurement of Thermal Inertia

Radiometric measurements determine thermal inertia for geologic materials. Measurements are correlated with data obtained by remote sensing, for discriminating varieties of rock encountered when exploring for minerals by aircraft or by satellites equipped with infrared scanners.

Kahle, A. B.↗