Search NASA⌕ Search

SEARCH · Search NASA

Results for “Aerospace”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 289 records · Page 16
All sourcesNASA NTRSDOE OSTI
NASA NTRS1969

Combustion Processes in the Aerospace Environment

The aerospace environment introduces new and enhanced fire hazards because the special atmosphere employed may increase the frequency and intensity of fires, because the confinement associated with aerospace systems adversely affects the dynamics of fire development and control, and because the hostile external environments limit fire control and rescue operations. Oxygen enriched atmospheres contribute to the fire hazard in aerospace systems by extending the list of combustible fuels, increasing the probability of ignition, and increasing the rates of fire spread and energy release. A system for classifying atmospheres according to the degree of fire hazard, based on the heat capacity of the atmosphere per mole of oxygen, is suggested. A brief exploration of the dynamics of chamber fires shows that such fires will exhibit an exponential growth rate and may grow to dangerous size in a very short time. Relatively small quantities of fuel and oxygen can produce a catastrophic fire in a closed chamber.

Huggett, Clayton↗
NASA NTRS2016

Dynamic Gas Flow Effects on the ESD of Aerospace Vehicle Surfaces

The purpose of this work is to develop a dynamic version of Paschen's Law that takes into account the flow of ambient gas past aerospace vehicle surfaces. However, the classic Paschen's Law does not take into account the flow of gas of an aerospace vehicle, whose surfaces may be triboelectrically charged by dust or ice crystal impingement, traversing the atmosphere. The basic hypothesis of this work is that the number of electron-ion pairs created per unit distance by the electric field between the electrodes is mitigated by the electron-ion pairs removed per unit distance by the flow of gas. The revised Paschen equation must be a function of the mean velocity, v(sub xm), of the ambient gas and reduces to the classical version of Paschen's law when the gas mean velocity, v(sub xm) = 0. New formulations of Paschen's Law, taking into account Mach number and dynamic pressure, derived by the authors, will be discussed. These equations will be evaluated by wind tunnel experimentation later this year. Based on the results of this work, it is hoped that the safety of aerospace vehicles will be enhanced with a redefinition of electrostatic launch commit criteria. It is also possible that new products, such as new anti-static coatings, may be formulated from this data.

Paschens Law↗
NASA NTRS2016

Dynamic Gas Flow Effects on the ESD of Aerospace Vehicle Surfaces

The purpose of this work is to develop a dynamic version of Paschen's Law that takes into account the flow of ambient gas past aerospace vehicle surfaces. However, the classic Paschen's Law does not take into account the flow of gas of an aerospace vehicle, whose surfaces may be triboelectrically charged by dust or ice crystal impingement, traversing the atmosphere. The basic hypothesis of this work is that the number of electron-ion pairs created per unit distance by the electric field between the electrodes is mitigated by the electron-ion pairs removed per unit distance by the flow of gas. The revised Paschen equation must be a function of the mean velocity, v(sub xm), of the ambient gas and reduces to the classical version of Paschen's law when the gas mean velocity, v(sub xm) = 0. New formulations of Paschen's Law, taking into account Mach number and dynamic pressure, derived by the authors, will be discussed. These equations will be evaluated by wind tunnel experimentation later this year. Based on the results of this work, it is hoped that the safety of aerospace vehicles will be enhanced with a redefinition of electrostatic launch commit criteria. It is also possible that new products, such as new anti-static coatings, may be formulated from this data.

Electrostatic Discharge↗
NASA NTRS2017

Ni-Ti Alloys for Aerospace Bearing Applications

Nickel-rich Ni-Ti alloys are emerging candidate materials for aerospace bearing applications. These alloys exhibit a unique combination of physical, chemical, and tribological properties that are highly relevant to challenging aerospace bearings and other mechanical components. Despite being made solely from metals, Ni-Ti alloys are classified as intermetallics with properties akin to both metals and ceramics. For instance, like metals, they are electrically conductive but they tend to be brittle like ceramics. When properly processed, they have high hardness, low elastic modulus and an extensive elastic deformation range that imparts extraordinarily high resilience and resistance to denting. New alloy compositions enable simpler thermal processing and machining and intensive microstructural analyses have helped elucidate the materials science mechanisms governing hardness. In this paper, the application of state-of-art in NiTi alloys for aerospace bearings and mechanical components is explored. In addition to reviewing future trends and remaining challenges, the unique approaches and methods of tailoring bearing design to accommodate NiTis unique properties is discussed.

intermetallics↗
NASA NTRS2018

Summary of 2017 NASA Workshop on Assessment of Advanced Battery Technologies for Aerospace Applications

A workshop on assessment of battery technologies for future aerospace applications was held in Cleveland, OH on August 16-17. The focus of the workshop, hosted by NASA GRC, was to assess (1) the battery needs for future aerospace missions, (2) the state of battery technology and projected technology advances, and (3) the need for additional investments for future aerospace missions. The workshop had 109 attendees that included internationally recognized technology leaders from academia and national laboratories, high level executives from government and industry, small businesses, and startup companies. A significant portion of the workshop was focused on batteries for electrified aircraft. The presentation will summarize the finding on the state of battery technologies for electrified aircraft and will include assessment of current state of battery technology, gaps in battery technology for application in electrified aircraft, and recommended technology development options for meeting near-term and long-term needs of electrified aircraft.

Misra, Ajay↗
NASA NTRS2018

Aerospace Ceramic Materials: Thermal, Environmental Barrier Coatings and SiC/SiC Ceramic Matrix Composites for Turbine Engine Applications

Ceramic materials play increasingly important roles in aerospace applications because ceramics have unique properties, including high temperature capability, high stiffness and strengths, excellent oxidation and corrosion resistance. Ceramic materials also generally have lower densities as compared to metallic materials, making them excellent candidates for light-weight hot-section components of aircraft turbine engines, rocket exhaust nozzles, and thermal protection systems for space vehicles when they are being used for high-temperature and ultra-high temperature ceramics applications. Ceramic matrix composites (CMCs), including non-oxide and oxide CMCs, are also recently being incorporated in gas turbine engines for high pressure and high temperature section components and exhaust nozzles. However, the complexity and variability of aerospace ceramic processing methods, compositions and microstructures, the relatively low fracture toughness of the ceramic materials, still remain the challenging factors for ceramic component design, validation, life prediction, and thus broader applications. This ceramic material section paper presents an overview of aerospace ceramic materials and their characteristics. A particular emphasis has been placed on high technology level (TRL) enabling ceramic systems, that is, turbine engine thermal and environmental barrier coating systems and non-oxide type SiC/SiC CMCs. The current status and future trend of thermal and environmental barrier coatings and SiC/SiC CMC development and applications are described.

Thermal Barrier Coatings↗
NASA NTRSDate not supplied

Modal Correlation of Complex Aerospace Joints Using Automated Variable Substitution

A critical task involved with being able to predict flight loads accurately in aerospace finite element models (FEMs) is the prior verification of the FEMs by conducting modal survey testing (MST). Experience comparing dynamic response of initial FEMs to MST data tends to demonstrate that FEMs can have unacceptable accuracy even when best modeling practices are followed. One inherent source of inaccuracy in linear dynamic FEMs is the modeling of nonlinear joints with mechanisms such as spherical bearings. These joints are usually designed to freely translate or rotate under the high levels of loading experienced in flight. Engineers who create linear FEMs conventionally model these joints without any stiffness in the mechanism degrees of freedom to meet this design intent. However, inaccuracy is observed during test validation of these FEMs, which usually relies on low-level force excitation orders of magnitude below flight load levels. This low-level modal test rarely overcomes the joint friction that is present, and thus the mechanism joints are able to react loads. This divide between the test results and the FEM creates a significant challenge to the engineer who is performing the correlation, in that the engineer has no basis for what stiffness value should be used to make the FEM match the test results. A compounding challenge is that complicated built-up aerospace structures commonly have multiple joints through a load path where each joint will “stick” and “slip” at different levels of force input. Explicitly matching the dynamics of a system containing these nonlinear mechanisms would require a nonlinear FEM, which is prohibitively costly for dynamic simulations of most aerospace systems. The objective of this paper is to present a workflow that can efficiently cycle through many iterations of a FEM, allowing a Monte Carlo style examination of the design space to identify candidate stiffness values for nonlinear mechanism joints. The outlined approach is specific to MSC Nastran and utilizes MSC Nastran’s symbolic substitution capabilities, coupled with the IMAT™ and Attune™ software packages developed by ATA Engineering, Inc. (ATA). The workflow is demonstrated with a case study from the correlation effort for The Boeing Company’s Crew Space Transportation (CST)-100 Starliner FEM. Keywords: Correlation, MSC Nastran, IMAT™, Attune™, Finite Element Model, Modal Testing

Correlation↗
NASA NTRS2020

Bonding to Bulk Metallic Glass using Aerospace-Grade Structural Adhesive

Bulk metallic glasses (BMGs) are non-crystalline metals with growing applications in aerospace. Due to their amorphous nature, BMGs generally exhibit stronger mechanical properties than most crystalline alloys and are more corrosion resistant. The limited reactivity of a corrosion resistant surface may explain the difficulty in establishing robust bonds to certain adhesives, especially commonly used structural adhesives for aerospace applications. Here, an amine cured aerospace adhesive was used for bonding an iron-nickel based BMG satellite component. Various types of processes were explored to avoid adhesive failure and increase bond strength. It was found that the BMG required specific chemical derivatization of the metal surface in order to achieve cohesive failure. Surface analysis was used to determine the mechanisms of adhesion enhancement. The process was optimized to maximize bond strength. This work helps explain the difficulties in bonding BMG materials and provides strategies for design of future bonded BMG components.

Roberts, Rose↗
NASA NTRSDate not supplied

High Temperature Devices for Aerospace Applications

This presentation will overview important new capabilities and benefits that next-generation higher temperature electronics promise for a variety of aerospace systems and missions. Initial aerospace infusions of higher temperature electronics to be discussed include jet engines and the prolonged robotic exploration of the Venus surface. Complete redesign of systems compared to prior conventional electronics practices would yield the most revolutionary benefits. However, the inherent higher risk and expense associated with new technology adoption will likely drive a more evolutionary technology infusion process, especially since flight qualification demands large safety margins and testing that ensures reliable operation for far longer than actual mission duration. SiC pn-junction based devices are inherently capable of the most durable operation at the highest application temperatures compared other transistor technologies, but such integrated circuits (ICs) will never achieve integration levels near today’s silicon ICs. Extreme temperature high-power devices will also be de-rated compared to room-temperature performance. While the high temperature market will always be small compared to the conventional temperature mass-market, compatibility and leveraging of existing foundry manufacturing is vital to the establishment of a sustainable high temperature electronics ecosystem sufficient to significantly improve aerospace systems.

High Temperature↗
NASA NTRSDate not supplied

Comparison of the Nowcast of Aerospace Ionizing Radiation System (NAIRAS) With ISS Measurements

The Nowcast of Aerospace Ionizing Radiation System (NAIRAS) is a sophisticated physics-based model that has been providing real-time global predictions of cosmic radiation exposure, pertinent to both galactic and solar sources, to air travelers for a decade. The utility of NAIRAS, however, extends beyond the atmospheric ionizing radiation environment. The recently developed NAIRAS 3.0 version demonstrates an expansion of its domain to the space radiation environment. This extension incorporates an additional trapped inner belt proton source, coupled with altitude-dependent and rigidity-dependent geomagnetic shielding for galactic cosmic rays (GCR) and solar energetic particle (SEP) protons. The latest version of NAIRAS operates in two modes: real-time global predictions of the atmospheric radiation environment and a user-specified run-on-request service for global dosimetric calculations or predictions of dosimetric and particle flux quantities along user-uploaded flight path. It is available to the public at the Community Coordinated Modeling Center (CCMC). In this work, we present the validation exercises that have been conducted using the Automated Radiation Measurements for Aerospace Safety (ARMAS) onboard the International Space Station (ISS), thereby establishing NAIRAS's efficacy in predicting space radiation exposure. As such, NAIRAS 3.0 holds significant potential for human safety and technological advancement in aerospace travel and exploration.

Daniel Phoenix↗
NASA NTRSDate not supplied

Effect of Composition Variation on Isothermal Rapid Curing Resins for Aerospace Applications

To meet the projected demand for single-aisle composite aircraft in 2040, the production rate of these aircraft will need to increase by four to six times what is currently achievable. A composite manufacturing process with the potential to enable the targeted rates is isothermal resin infusion where infusion and cure occur at the same temperature. However, presently there is not an accepted aerospace-grade resin that can support this isothermal infusion process and maintain acceptable resin properties. Therefore, resin development initiatives have designed anionic catalyzed epoxy systems capable of isothermal infusion and rapid cure at a temperature below 100 ˚C in one hour. High-performance aerospace properties are achieved after undergoing a freestanding post-cure. The resins facilitate faster, energy efficient production cycles by reducing the time and temperature required for cure and eliminating temperature ramps typically required of materials used in the aerospace industry. This work discusses several of the developed resin systems and the impact of varying composition on rheological, thermal, and mechanical properties. Carbon fiber composites were fabricated for one composition by resin transfer molding to demonstrate the potential of these isothermal, rapid cure systems for meeting industry needs.

resin transfer molding↗
NASA NTRSDate not supplied

Evaluating Crystallinity in Thermoplastic Composites for Aerospace Applications

Polymer matrix composites (PMCs) offer many benefits for the aerospace industry due to their potential for weight reduction when compared to metal or ceramic based materials. Most PMCs currently in flight use thermoset matrices, however, thermoplastic resins are being explored as alternatives due to their ability to be remelted, which is of particular interest due to the potential for in-situ repair and faster production. Most thermoplastic resins are semicrystalline polymers. The properties of semicrystalline thermoplastics are directly influenced by their crystallinity, which can vary due to many factors including thermal treatments, environmental conditions, and mechanical deformation. Within thermoplastic PMC parts, crystallinity gradients can arise due to variations in part geometry, across part thicknesses, and along bonded joints. Monitoring the crystallinity of thermoplastic composites is key to ensuring these materials meet the high demands required for aerospace. Several different analytical techniques exist that can be used to characterize the bulk crystallinity of thermoplastic materials. However, many existing methods lack the specificity required to identify the subtle variations in crystallinity that may play a significant role in the performance and durability of PMC parts. Because of this, a significant amount of work is still required to fully characterize and understand the crystallinity profiles of thermoplastic PMCs and the resulting impact to material properties. This talk discusses the use of multiple techniques such as Differential Scanning Calorimetry, Polarized Light Optical Microscopy, and Fourier-Transform Infrared Spectroscopy to characterize the crystallinity in carbon fiber/thermoplastic composites. Samples of different crystallinity profiles were manufactured using various cooling procedures. This work aims to provide the fundamental data necessary to understand the effects of crystallinity on thermoplastic PMCs, which is key to advancing their use in aerospace applications.

Thermoplastics↗
NASA NTRS1965

Aerospace bibliography, third edition

This third edition bibliography lists books and teaching aids related to aeronautics and space. Aeronautics titles are limited to aerospace-related research subjects, and books on astronomy to those directly related to space exploration. Also listed are pertinent references like pamphlets, films, film strips, booklets, charts, pictures, periodicals, and sources of information on specific space subjects available from aerospace industry companies. Reading levels for each document are indicated according to primary, intermediate, upper elementary, secondary, and adult or college.

SPACE EXPLORATION↗
NASA NTRS2001

Lower body negative pressure as a tool for research in aerospace physiology and military medicine

Lower body negative pressure (LBNP) has been extensively used for decades in aerospace physiological research as a tool to investigate cardiovascular mechanisms that are associated with or underlie performance in aerospace and military environments. In comparison with clinical stand and tilt tests, LBNP represents a relatively safe methodology for inducing highly reproducible hemodynamic responses during exposure to footward fluid shifts similar to those experienced under orthostatic challenge. By maintaining an orthostatic challenge in a supine posture, removal of leg support (muscle pump) and head motion (vestibular stimuli) during LBNP provides the capability to isolate cardiovascular mechanisms that regulate blood pressure. LBNP can be used for physiological measurements, clinical diagnoses and investigational research comparisons of subject populations and alterations in physiological status. The applications of LBNP to the study of blood pressure regulation in spaceflight, groundbased simulations of low gravity, and hemorrhage have provided unique insights and understanding for development of countermeasures based on physiological mechanisms underlying the operational problems.

Review↗
NASA NTRS1997

Aerospace Medicine and Biology: A Continuing Bibliography With Indexes

This issue of Aerospace Medicine and Biology, A Continuing Bibliography with Indexes NASA SP-7O11 lists reports, articles, and other documents recently announced in the NASA STI Database. In its subject coverage, Aerospace Medicine and Biology concentrates on the biological, physiological, psychological, and environmental effects to which humans are subjected during and following simulated or actual flight in the Earth's atmosphere or in interplanetary space. References describing similar effects on biological organisms of lower order are also included. Such related topics as sanitary problems, pharmacology, toxicology, safety and survival, life support systems, exobiology, and personnel factors receive appropriate attention. Applied research receives the most emphasis, but references to fundamental studies and theoretical principles related to experimental development also qualify for inclusion.

BIBLIOGRAPHIES↗
NASA NTRS2014

The 42nd Aerospace Mechanism Symposium

The Aerospace Mechanisms Symposium (AMS) provides a unique forum for those active in the design, production, and use of aerospace mechanisms. A major focus is the reporting of problems and solutions associated with the development, and flight certification of new mechanisms.

Tribology↗
NASA NTRS2014

Novel Wiring Technologies for Aerospace Applications

Because wire failure in aerospace vehicles could be catastrophic, smart wiring capabilities have been critical for NASA. Through the years, researchers at Kennedy Space Center (KSC) have developed technologies, expertise, and research facilities to meet this need. In addition to aerospace applications, NASA has applied its knowledge of smart wiring, including self-healing materials, to serve the aviation industry. This webinar will discuss the development efforts of several wiring technologies at KSC and provide insight into both current and future research objectives.

novel↗