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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 NTRS2010

A Review of International Space Station Habitable Element Equipment Offgassing Characteristics

Crewed spacecraft trace contaminant control employs both passive and active methods to achieve acceptable cabin atmospheric quality. Passive methods include carefully selecting materials of construction, employing clean manufacturing practices, and minimizing systems and payload operational impacts to the cabin environment. Materials selection and manufacturing processes constitute the first level of equipment offgassing control. An element-level equipment offgassing test provides preflight verification that passive controls have been successful. Offgassing test results from multiple International Space Station (ISS) habitable elements and cargo vehicles are summarized and implications for active contamination control equipment design are discussed

Perry, Jay L.↗
NASA NTRS2012

An Elementary Overview of the Selection of Materials for Service in Oxygen-Enriched Environments

The process for selecting materials for use in oxygen or oxygen-enriched environments is one that continues to be investigated by many industries due to the importance to those industries of oxygen systems. There are several excellent resources available to assist oxygen systems design engineers and end-users, with the most comprehensive being ASTM MNL-36, Safe Use of Oxygen and Oxygen Systems: Handbook for Design, Operation and Maintenance, 2nd Edition. ASTM also makes available several standards for oxygen systems. However, the ASTM publications are extremely detailed, and typically designed for professionals who already possess a working knowledge of oxygen systems. No notable resource exists, whether an ASTM or other organizational publication, which can be used to educate engineers or technicians who have no prior knowledge of the nuances of oxygen system design and safety. This paper will fill the void for information needed by organizations that design or operate oxygen systems. The information in this paper is not new information, but is a concise and easily understood summary of selecting materials for oxygen systems. This paper will serve well as an employee s first introduction to oxygen system materials selection, and probably the employee s first introduction to ASTM.

Davis, Samuel Eddie↗
NASA NTRS1975

Refurbishment of NASA aircraft with fire-retardant materials

Selected fire-retardant materials for possible application to commercial aircraft are described. The results of flammability screening tests and information on the physical and chemical properties of both original and newly installed materials after extended use are presented in tabular form, with emphasis on wear properties, strength, puncture and tear resistances, and cleanability.

Supkis, D. E.↗
NASA NTRS1972

Determination of contamination character of materials in space technology testing

The contamination character of selected materials used in space technology testing is presented. Many of these materials contain components that become volatile in a space environment. Most previous data were limited to weight loss or vapor pressure. However, these parameters are not necessarily a direct measure of the contamination character of these materials. Selected materials were exposed to a thermal-vacuum environment, and the degree of contamination was measured by collecting the outgases from these materials on a cold test mirror surface. The degradation of reflectivity of the mirror was measured over a spectral range from 1100 A to 2.5 microns. Half the mirror's surface was also exposed to UV irradiation to determine its effects on the contaminative character of the depositing outgases. The amount of deposit per unit area was measured by microbalances mounted near the mirror; the sensor of one microbalance was UV irradiated. A quadrupole mass spectrometer was used to determine the composition of the outgases.

Haynes, D. L.↗
NASA NTRS1992

HSCT materials and structures: An MDC perspective

The key High Speed Civil Transport (HSCT) features which control the materials selection are discussed. Materials are selected based on weight and production economics. The top-down and bottoms-up approaches to material selection are compared for the Mach 2.4 study baseline aircraft. The key materials and structures related tasks which remain to be accomplished prior to proceeding with the building of the HSCT aircraft are examined.

Sutton, Jay O.↗
NASA NTRS1996

Optical Properties of Selective Emitter Materials for Thermophotovoltaic Applications

We investigate the optical properties of new "selective emitter" materials for possible use in high-efficiency thermophotovoltaic power systems. These are systems which directly convert heat to radiation at a wavelength closely matched to the bandgap energy of the solar cell. Candidate materials which have strong absorption lines fairly close to the bandgap of good solar-cell materials were chosen for study. Their emittance was measured as a function of wavelength to evaluate their promise as selective TPV emitters. Useful and informative results were obtained. Some of these results were presented at a January 1996 solar energy conference of the American Institute of Aeronautics and Astronautics.

Hambourger, Paul D.↗
NASA NTRS1968

Evaluation of ignition mechanisms in selected nonmetallic materials

Test program evaluates thermal and electric ignition mechanisms in selected nonmetallic materials found in spacecraft with concentrated oxygen atmospheres. The phenomena evaluated were spontaneous ignition, ignition of flammable vapor by a spark, and ignition by an arc where the arc produces the combustible vapor and the ignition source.

Gerstein, M.↗
NASA NTRS1995

Hardware cleanliness methodology and certification

Inadequacy of mass loss cleanliness criteria for selection of materials for contamination sensitive uses, and processing of flight hardware for contamination sensitive instruments is discussed. Materials selection for flight hardware is usually based on mass loss (ASTM E-595). However, flight hardware cleanliness (MIL 1246A) is a surface cleanliness assessment. It is possible for materials (e.g. Sil-Pad 2000) to pass ASTM E-595 and fail MIL 1246A class A by orders of magnitude. Conversely, it is possible for small amounts of nonconforming material (Huma-Seal conformal coating) to not present significant cleanliness problems to an optical flight instrument. Effective cleaning (precleaning, precision cleaning, and ultra cleaning) and cleanliness verification are essential for contamination sensitive flight instruments. Polish cleaning of hardware, e.g. vacuum baking for vacuum applications, and storage of clean hardware, e.g. laser optics, is discussed. Silicone materials present special concerns for use in space because of the rapid conversion of the outgassed residues to glass by solar ultraviolet radiation and/or atomic oxygen. Non ozone depleting solvent cleaning and institutional support for cleaning and certification are also discussed.

Harvey, Gale A.↗
DOE OSTI2025

Machine Learning-Driven Optimization of Building Enclosures for Moisture Durability and Thermal Performance

The design of moisture-durable building enclosures with low embodied carbon often involves an iterative process of selecting the materials for the specific exposure conditions to meet the performance requirements. While hygrothermal simulations are commonly used to evaluate moisture durability, they often require advanced expertise for proper implementation. Machine learning (ML) provides a promising alternative by streamlining the design process and minimizing the reliance on complex simulations. This study presents a machine learning-based approach for predicting moisture durability in residential wall assemblies. The ML model was trained to estimate the mold index and maximum moisture content of various layers under typical exposure conditions. The model achieved a high predictive accuracy, with a coefficient of determination (R²) exceeding 0.90 when compared to traditional hygrothermal simulations on materials that were not part of training the ML model. Building on these results, the ML model was developed into a practical tool for optimizing wall assembly designs. This tool allows users to automatically optimize material selections based on energy, moisture, and carbon performance criteria. By incorporating multi-objective optimization, the tool identifies configurations that minimize embodied carbon while maintaining moisture safety and code-compliant thermal performance. Additionally, it provides insights into how material choices influence assembly durability, energy efficiency, and carbon reduction. The tool will be implemented in the Building Science Advisor (BSA) to enhance its performance and provide more granularity on the results. This research highlights the potential for ML-driven tools to simplify the design of high-performance building enclosures, offering architects and engineers a faster, more efficient way to balance critical performance factors.

Salonvaara, Mikael [ORNL] (ORCID:0000000318991554)↗
NASA NTRS1973

Surface electrical properties experiment study phase, volume 3

The reliability and quality assurance system and procedures used in developing test equipment for the Lunar Experiment projects are described. The subjects discussed include the following: (1) documentation control, (2) design review, (3) parts and materials selection, (4) material procurement, (5) inspection procedures, (6) qualification and special testing, and failure modes and effects analysis.

Source record↗
NASA NTRS1978

Wear of seal materials used in aircraft propulsion systems

The various types of seal locations in a gas turbine engine are described, and the significance of wear to each type is reviewed. Starting with positive contact shaft seals, existing material selection guidelines are reviewed, and the existing PV (contact pressure X sliding velocity) criteria for selecting seal materials are discussed, along with the theoretical background for these criteria. Examples of wear mechanisms observed to operate in positive contact seals are shown. Design features that can extend the operating capabilities of positive contact seals, including pressure balancing and incorporation of hydrodynamic lift are briefly discussed. It is concluded that, despite the benefits arising from these design features, improved positive contact seal materials from the standpoint of wear, erosion and oxidation resistance will be necessary for further improvements in seal performance and durability, and to meet stringent future challenges.

Bill, R. C.↗
NASA NTRS1996

Materials Assessment of Components of the Extravehicular Mobility Unit

Current research interests for Extravehicular Mobility Unit (EMU) design and development are directed toward enhancements of the Shuttle EMU, implementation of the Mark 3 technology for Shuttle applications, and development of a next generation suit (the X suit) which has applications for prolonged space flight, longer extravehicular activity (EVA), and Moon and Mars missions. In this research project two principal components of the EMU were studied from the vantage point of the materials and their design criteria. An investigation of the flexible materials which make up the lay-up of materials for abrasion and tear protection, thermal insulation, pressure restrain, etc. was initiated. A central focus was on the thermal insulation. A vacuum apparatus for measuring the flexibility of the materials was built to access their durability in vacuum. Plans are to include a Residual Gas Analyzer on the vacuum chamber to measure volatiles during the durability testing. These tests will more accurately simulate space conditions and provide information which has not been available on the materials currently used on the EMU. Durability testing of the aluminized mylar with a nylon scrim showed that the material strength varied in the machine and transverse directions. Study of components of the EMU also included a study of the EMU Bearing Assemblies as to materials selection, engineered materials, use of coatings and flammability issues. A comprehensive analysis of the performance of the current design, which is a stainless steel assembly, was conducted and use of titanium alloys or engineered alloy systems and coatings was investigated. The friction and wear properties are of interest as are the general manufacturing costs. Recognizing that the bearing assembly is subject to an oxygen environment, all currently used materials as well as titanium and engineered alloys were evaluated as to their flammability. An aim of the project is to provide weight reduction since bearing weights constitute 1/3 of the total EMU weight. Our investigations have shown favorable properties using a titanium or nickel base alloy in conjunction with a coating system. Interest lies in developing titanium as a more nonflammable material. Methodology for doing this lies in adding coatings and surface alloying the titanium. This report is brief and does not give all necessary details. The reader should contact the authors as to the detailed study and for viewing of raw data.

Olivas, John D.↗
NASA NTRS2015

Superelastic Ball Bearings: Materials and Design to Avoid Mounting and Dismounting Brinell Damage in an Inaccessible Press-fit Application-: Detailed Analysis - II

Rolling element bearings utilized in precision rotating machines require proper alignment, preload, and interference fits to ensure overall optimum performance. Hence, careful attention must be given to bearing installation and disassembly procedures to ensure the above conditions are met. Usually, machines are designed in such a way that bearings can be pressed into housings or onto shafts through the races without loading the rolling elements. However, in some instances, either due to limited size or access, a bearing must be installed or removed in such a way that the load path travels through the rolling elements. This can cause high contact stresses between the rolling elements and the races and introduces the potential for Brinell denting of the races. This paper is a companion to the Part I paper by the authors that discusses material selection and the general design philosophy for the bearing. Here, a more in-depth treatment is given to the design of a dent-resistant bearing utilizing a superelastic alloy, 60NiTi, for the races. A common bearing analysis tool based on rigid body dynamics is used in combination with finite element simulations to design the superelastic bearing. The primary design constraints are prevention of denting and avoiding the balls riding over the edge of the race groove during a blind disassembly process where the load passes through the rolling elements. Through an iterative process, the resulting bearing geometry is tailored to improve axial static load capability compared to a deep-groove ball bearing of the same size. The results suggest that careful selection of materials and bearing geometry can enable blind disassembly without damage to the raceways, which is necessary in the current application (a compressor in the International Space Station Environmental Control and Life Support System), and results in potential design flexibility for other applications, especially small machines with miniature bearings.

metals↗
NASA NTRS1989

Space Station material life considerations

Space Station life requirements for the overall system are currently stated as thirty years of constant space operation. This aspect of constant in-space operation and long life brings in environmental compatibility requirements which place severe new constraints on material selection. Activities within the United States are currently addressing many of these material selection issues including development of coatings and other space-durable materials, material selection methodology, and life certification methodology. A summary of these activities is presented.

Leger, L. J.↗
NASA NTRS1977

Heat sink structural design concepts for a hypersonic research airplane

Hypersonic research aircraft design requires careful consideration of thermal stresses. This paper relates some of the problems in a heat sink structural design that can be avoided by appropriate selection of design options including material selection, design concepts, and load paths. Data on several thermal loading conditions are presented on various conventional designs including bulkheads, longerons, fittings, and frames. Results indicate that conventional designs are inadequate and that acceptable designs are possible by incorporating innovative design practices. These include nonintegral pressure compartments, ball-jointed links to distribute applied loads without restraining the thermal expansion, and material selections based on thermal compatibility.

Taylor, A. H.↗