Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “environments specification”

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 595 records · Page 33
All sourcesNASA NTRSDOE OSTI
NASA NTRS1994

Motion estimation of objects in KC-135 microgravity

The simulated microgravity environment aboard a KC-135 aircraft flying along a parabolic trajectory was used to study the ability of an autonomous space robot to grasp a freely translating and rotating object. Since the KC-135 cabin environment and the instrumentation for the Extravehicular Activity Helper/Retriever (EVAHR) do not provide a practical intertial reference frame, estimators based on the extended Kalman filter algorithm were used to model the relative translational dynamics of the KC-135 and the EVAHR. The estimator algorithms require intensive mathematical computation and therefore, i860 real-time. Estimator design, implementation concerns, and issues specific to the KC-135 environment are discussed and the architecture of the KC-135 translational state estimator is depicted.

Hewgill, Lisa↗
NASA NTRSDate not supplied

NASA Hypersonic Technology Project (HTP) Sic/Sic Research for Hypersonic Airframe Hot Structures

NASA, DoD, and industry have a vision for reusable hypersonic vehicles (Mach > 5). The realization of this vision will require high-specific-strength, high-temperature, reusable structures. In the sub-sonic and super-sonic flight regimes, high-specific-strength structures can be obtained via the use of aluminum, titanium, and composite materials. In the high-temperature environments associated with hypersonic flight, high specific strength is obtained via refractory-composite materials. NASA Langley Research Center has multiple efforts focused on evaluating refractory-composites for use as airframe hot structures for reusable hypersonic vehicles. Current efforts span the entire building-block approach, including coupon, element, subcomponent, and component manufacturing and testing. The coupon level work includes progressive damage testing and analysis, restrained thermal growth testing, stressed oxidation testing, and evaluation of laminate properties for several layup architectures. Element testing includes evaluation of over-temperature capability and co-processed bonding, fastener development, and analysis and testing of beaded (corrugated) panels. Subcomponent level work includes a solid rocket motor booster fin and a portion of a control surface, and component level work includes a control surface static test article. The current presentation will provide an update of work being performed at NASA, which is expected to transition refractory-composite materials to reusable hypersonic vehicles.

Hot structures↗
NASA NTRS2002

Radiation Hardness Assurance for Space Systems

The space radiation environment can lead to extremely harsh operating conditions for on-board electronic box and systems. The characteristics of the radiation environment are highly dependent on the type of mission (date, duration and orbit). Radiation accelerates the aging of the electronic parts and material and can lead to a degradation of electrical performance; it can also create transient phenomena on parts. Such damage at the part level can induce damage or functional failure at electronic box, subsystem, and system levels. A rigorous methodology is needed to ensure that the radiation environment does not compromise the functionality and performance of the electronics during the system life. This methodology is called hardness assurance. It consists of those activities undertaken to ensure that the electronic piece parts placed in the space system perform to their design specifications after exposure to the space environment. It deals with system requirements, environmental definitions, part selection, part testing, shielding and radiation tolerant design. All these elements should play together in order to produce a system tolerant to.the radiation environment. An overview of the different steps of a space system hardness assurance program is given in section 2. In order to define the mission radiation specifications and compare these requirements to radiation test data, a detailed knowledge of the space environment and the corresponding electronic device failure mechanisms is required. The presentation by J. Mazur deals with the Earth space radiation environment as well as the internal environment of a spacecraft. The presentation by J. Schwank deals with ionization effects, and the presentation by T. Weatherford deals with Single particle Event Phenomena (SEP) in semiconductor devices and microcircuits. These three presentations provide more detailed background to complement the sections 3 and 4. Part selection and categorization are discussed in section 5. Section 6 presents the organization of the hardness assurance within a project. Section 7 discusses emerging radiation hardness assurance issues.

Poivey, Christian↗
NASA NTRS1992

Design and optimization of a self-deploying single axis tracking PV array

This study was performed in order to design a tracking photovoltaic (PV) array and optimize the design for maximum specific power. The design considerations were minimal deployment time, high reliability, and small stowage volume. The array design was self-deployable, from a compact stowage configuration, using a passive pressurized gas deployment mechanism. The array structural components consist of a combination of beams, columns, and cables used to deploy and orient a flexible PV blanket. Each structural component of the design was analyzed to determine the size necessary to withstand the various forces to which it would be subjected. An optimization was performed to determine the array dimensions and blanket geometry which produce the maximum specific power. The optimization was performed for both lunar and Martian environments with 4 types of PV blankets (silicon, GaAs/Ge, GaAs CLEFT, and amorphous silicon). For the lunar environment, the amorphous silicon array produced the highest specific power, whereas, for Mars the GaAs CLEFT array produced the highest specific power. A comparison was made to a fixed PV tent array of similar design. The tracking array produced a higher specific power with all types of the PV blankets examined except amorphous silicon at both locations.

Colozza, Anthony J.↗
NASA NTRS1992

Design and optimization of a self-deploying single axis tracking PV array

This study was performed in order to design a tracking photovoltaic (PV) array and optimize the design for maximum specific power. The design considerations were minimal deployment time, high reliability, and small stowage volume. The array design was self-deployable, from a compact stowage configuration, using a passive pressurized gas deployment mechanism. The array structural components consist of a combination of beams, columns, and cables used to deploy and orient a flexible PV blanket. Each structural component of the design was analyzer to determine the size necessary to withstand the various forces to which it would be subjected. An optimization was performed to determine the array dimensions and blanket geometry which produce the maximum specific power. The optimization was performed for both lunar and Martian environments with 4 types of PV blankets (silicon, GaAs/Ge, GaAs CLEFT, and amorphous Silicon). For the lunar environment, the amorphous silicon array produced the highest specific power, whereas, for Mars the GaAs CLEFT array produced the highest specific power. A comparison was made to a fixed PV tent array of similar design. The tracking array produced a higher specific power with all types of the PV blankets examined except amorphous silicon at both locations.

Colozza, Anthony J.↗
DOE OSTI2025

Quantifying CO 2 Plume Stabilization at Carbon Storage Projects, North Dakota, USA

This study presents an approach for quantifying when injected carbon dioxide (CO 2 ) stabilizes pursuant to carbon capture and storage (CCS) project permitting and site closure requirements. The distribution of mobile-phase CO 2 (CO 2 plume) will evolve within the storage reservoir during and after injection through both physical and chemical trapping mechanisms. CCS policies generally agree that the CO 2 plume’s migratory behavior in post-injection should demonstrate nonendangerment to the environment but do not provide specific guidance on how to meet the definition of plume stabilization, generating some uncertainty for operators. Plume stability herein means the CO 2 plume 1) changes size minimally and predictably in the storage reservoir such that it will not cross key boundaries identified in the permit and 2) does not pose a threat to human health, underground sources of drinking water (USDWs), and the environment because of lateral migration to areas where leakage pathways may exist. Published literature on plume metrics was reviewed to determine which metric(s) may be most appropriate for determining CO 2 plume stability. A technical approach that defines plume stabilization by estimating the rate of change in the geographic footprint of the CO 2 plume with respect to time was developed and illustrated using a case study from North Dakota, USA, as a proposed solution for CCS operators to apply at the project permitting stage. Any prospective CCS operator may benefit from using the same approach to inform the selection of pore space lease and monitoring areas and develop post-injection site care plans.

03 NATURAL GAS↗
NASA NTRS1984

Advances in electrophoretic separations

Free fluid electrophoresis is described using laboratory and space experiments combined with extensive mathematical modeling. Buoyancy driven convective flows due to thermal and concentration gradients are absent in the reduced gravity environment of space. The elimination of convection in weightlessness offers possible improvements in electrophoresis and other separation methods which occur in fluid media. The mathematical modeling suggests new ways of doing electrophoresis in space and explains various phenomena observed during past experiments. The extent to which ground based separation techniques are limited by gravity induced convection is investigated and space experiments are designed to evaluate specific characteristics of the fluid/particle environment. A series of experiments are proposed that require weightlessness and apparatus is developed that can be used to carry out these experiments in the near future.

Snyder, R. S.↗
NASA NTRS1996

Re-Engineering JPL's Mission Planning Ground System Architecture for Cost Efficient Operations in the 21st Century

Work carried out to re-engineer the mission analysis segment of JPL's mission planning ground system architecture is reported on. The aim is to transform the existing software tools, originally developed for specific missions on different support environments, into an integrated, general purpose, multi-mission tool set. The issues considered are: the development of a partnership between software developers and users; the definition of key mission analysis functions; the development of a consensus based architecture; the move towards evolutionary change instead of revolutionary replacement; software reusability, and the minimization of future maintenance costs. The current status and aims of new developments are discussed and specific examples of cost savings and improved productivity are presented.

Fordyce, Jess↗
NASA NTRS1976

Environmental parameters of shuttle support for life sciences experiments

The environments provided by the Orbiter vehicle and by the Spacelab will differ substantially from the environment provided by prior spacecraft. The specific design limits for each environmental parameter and expected operating characteristics are presented for both the Orbiter and the Spacelab. The environments are compared with those of earlier spacecraft and with the normal earth laboratory. Differences between the spacecraft environments and the normal laboratory environment and the impact of these differences on experiments and equipment design are discussed.

Waligora, J. M.↗
NASA NTRS1993

Modeling of PCG fluid dynamics: Salient results

Materials processing in space-based laboratories has already yielded higher quality crystals during previous space flights, and opportunities for several fluids experiments are anticipated during the extended duration missions planned for the future. Crystal growth in space benefits not only from its reduced gravity environment but also from the absence of the hydrostatic pressure which assists certain crystal growth and refinement methods. Gravity-driven phenomena are thus reduced in strength, and a purely diffusive fluid's behavior can be attained. In addition, past materials science experiments have shown that microgravity can also help produce larger crystals. While gravity-related effects are definitely curtailed in space, they are nevertheless present to some degree due to the acceleration environment onboard the spacecraft. This residual acceleration level is comprised of quasi-steady, oscillatory, and transient components, and is caused by a variety of mechanisms. For example, gravity gradient forces produce low frequency disturbances, and the operation of machinery, control thrusters, solar panels, human activity, etc. contribute to higher frequency accelerations. These disturbances are collectively referred to as g-jitter, and they can be deleterious to certain experiments where the minimization of the acceleration level is important. Advanced vibration isolation techniques can be utilized to actively filter out some of the detrimental frequencies and help in obtaining optimum results. However, the successful application of this technology requires the detailed analysis of candidate fluids experiments to gauge their response to g-jitter and to determine their acceleration sensitivities. Several crystal growth experiments in the Protein Crystal Growth (PCG) area, besides others, are expected to be carried out on future shuttle flights and on Space Station Freedom. The need for vibration isolation systems or components for microgravity science experiments can be expected to grow as experiments and available hardware becomes more complex. This technology will also find increased application as the science community develops an awareness of their specific needs relative to the environment available in manned space missions. Vibration isolation research strives to develop a microgravity environment requirement that defines tolerance limits on the allowable g-level, and provides the required technology to achieve it. This effort will assist in establishing the tolerable acceleration levels for specific fluids experiments. The primary effort is directed towards modeling PCG and the approach undertaken for this investigation is outlined. The objectives of this research are: (1) to computationally determine vibration sensitivity of protein crystal growth experiments; (2) determine if these experiments can benefit from vibration isolation techniques; and (3) provide realistic requirements for vibration isolation technology.

Ramachandran, N.↗
NASA NTRS2019

NASA IV&V's Cyber Range for Space Systems

A cyber range is a virtual environment that is used for cyberwarfare training and cyber technology development. It provides tools that help strengthen the stability, security and performance of cyber infrastructures and IT systems. NASA IV&V has created an adaptable virtual environment that is representative of a typical NASA mission system of systems environment that serves multiple purposes: Training of network defenders. Ability to perform simulated red vs blue training events. Ability to deploy mission specific technologies in a cyber contested environment. Ability to demonstrate vulnerabilities and their impact to ground and space systemsThe overall system is comprised of more than 70 virtual machines and physical infrastructure to demonstrate real-world cyber attacks against: email users, wireless networks, and physically implanted devices with command and control call-back. The cyber range was built to emulate a NASA precipitation satellite infrastructure.This presentation will give an overview of the virtual cyber range and how it was used to conduct a simulate red vs blue exercise with the goal of compromising the simulated spacecraft that utilizes real NASA flight software.

test and evaluation DT&E↗
DOE OSTI2021

Evaluating steam oxidation kinetics of environmental barrier coatings

Environmental barrier coatings (EBCs) are a commercially proven means of protecting SiC-based materials in gas turbine environments. However, there are little specific data in the literature on the impact of coatings like Yb 2 Si 2 O 7 on preventing accelerated SiO 2 growth in the presence of H 2 O. Quantification of reduced rates are necessary for evaluating and comparing EBC effectiveness and incorporation of silica growth rates into future EBC lifetime models. In this study, baseline kinetics of silica formation on bare Si and chemically vapor deposited (CVD) SiC in the 1250–1425 °C range were obtained via 100 h isothermal exposures in dry air and steam environments utilizing a SiC reaction tube to mitigate specimen volatility. An Arrhenius plot of the resulting rates was constructed, representing baseline minimum and maximum rates for Si and SiC oxidation at ambient pressure. Various EBC systems on CVD SiC substrates including air plasma sprayed (APS) EBCs with and without a Si bond coating and with surface roughening to enhance Yb 2 Si 2 O 7 adhesion were subjected to 1-h furnace cycle testing in air with 90vol%H 2 O at 1250–1350°C for up to 500 cycles. After exposure, silica formation rates were measured and compared to the baseline rates to assess EBC effectiveness, where EBC effectiveness is gauged as the propensity to reduce underlying rates of silica formation. With a Si bond coating, a ~180 µm Yb 2 Si 2 O 7 (YbDS) top coating reduced rates over the entire 1250°-1350°C range. Without a Si bond coating, ~60 µm (YbDS) coatings deposited directly onto CVD SiC exhibited poor adhesion, and had to be deposited onto substrates with enhanced roughness at 1350°C. Finally, while exhibiting good adhesion at 1350°C, overall the single layer YbDS coating exhibited a decreasing effectiveness from 1250° to 1350°C.

36 MATERIALS SCIENCE↗
NASA NTRS1984

Tailoring a software production environment for a large project

A software production environment was constructed to meet the specific goals of a particular large programming project. These goals, the specific solutions as implemented, and the experiences on a project of over 100,000 lines of source code are discussed. The base development environment for this project was an ordinary PWB Unix (tm) system. Several important aspects of the development process required support not available in the existing tool set.

Levine, D. R.↗
NASA NTRS1992

High order parallel numerical schemes for solving incompressible flows

The use of parallel computers for numerically solving flow fields has gained much importance in recent years. This paper introduces a new high order numerical scheme for computational fluid dynamics (CFD) specifically designed for parallel computational environments. A distributed MIMD system gives the flexibility of treating different elements of the governing equations with totally different numerical schemes in different regions of the flow field. The parallel decomposition of the governing operator to be solved is the primary parallel split. The primary parallel split was studied using a hypercube like architecture having clusters of shared memory processors at each node. The approach is demonstrated using examples of simple steady state incompressible flows. Future studies should investigate the secondary split because, depending on the numerical scheme that each of the processors applies and the nature of the flow in the specific subdomain, it may be possible for a processor to seek better, or higher order, schemes for its particular subcase.

Lin, Avi↗
DOE OSTI2023

Functional Meta-Analysis of the Proteomic Responses of Arabidopsis Seedlings to the Spaceflight Environment Reveals Multi-Dimensional Sources of Variability across Spaceflight Experiments

The human quest for sustainable habitation of extraterrestrial environments necessitates a robust understanding of life’s adaptability to the unique conditions of spaceflight. This study provides a comprehensive proteomic dissection of the Arabidopsis plant’s responses to the spaceflight environment through a meta-analysis of proteomics data from four separate spaceflight experiments conducted on the International Space Station (ISS) in different hardware configurations. Raw proteomics LC/MS spectra were analyzed for differential expression in MaxQuant and Perseus software. The analysis of dissimilarities among the datasets reveals the multidimensional nature of plant proteomic responses to spaceflight, impacted by variables such as spaceflight hardware, seedling age, lighting conditions, and proteomic quantification techniques. By contrasting datasets that varied in light exposure, we elucidated proteins involved in photomorphogenesis and skotomorphogenesis in plant spaceflight responses. Additionally, with data from an onboard 1 g control experiment, we isolated proteins that specifically respond to the microgravity environment and those that respond to other spaceflight conditions. This study identified proteins and associated metabolic pathways that are consistently impacted across the datasets. Notably, these shared proteins were associated with critical metabolic functions, including carbon metabolism, glycolysis, gluconeogenesis, and amino acid biosynthesis, underscoring their potential significance in Arabidopsis’ spaceflight adaptation mechanisms and informing strategies for successful space farming.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1990

Teamwork in high-risk environments analogous to space

Mountaineering expeditions combine a number of factors which make them potentially good analogs to the planetary exploration facet of long-duration space missions. A study of mountain climbing teams was conducted in order to evaluate the usefulness of the environment as a space analog and to specifically identify the factors and issues surrounding teamwork and 'successful' team performance in two mountaineering environments. This paper focuses on social/organizational factors, including team size and structure, leadership styles and authority structure which were found in the sample of 22 climb teams (122 individuals). The second major issue discussed is the construction of a valid performance measure in this high-risk environment.

Kanki, Barbara G.↗
NASA NTRS1991

LDEF space environments overview

The Long Duration Exposure Facility (LDEF) was launched into an Earth orbit during a period of minimum solar activity. It was retrieved almost 6 years later during a period of near maximum solar activity. In flight, the LDEF was passively stabilized in three axes and it flew in a near circular orbit having an inclination of 28.5 degs and an initial altitude of approx. 257 nautical miles. When the LDEF was retrieved, the orbit had decayed to an altitude of approx. 180 nautical miles. Specifically, the LDEF flew with one surface always facing the trailing direction, one surface facing Earth, and one surface facing into space. These facts made the LDEF an ideal platform to expose experiments to study the space environments and the effects of these environments on spacecraft materials and systems. An overview is provided of the specific space environments to which the LDEF experiments were exposed. The specific features are also pointed out of the LDEF that allow the effects of different environments to be isolated.

Kinard, William H.↗
DOE OSTI2022

Bioinspired oxidation of benzyl alcohol: The role of environment and nuclearity of the catalyst evaluated by multivariate analysis

Inspired by copper-containing enzymes such as galactose oxidase and catechol oxidase, in which distinct coordination environments and nuclearities lead to specific catalytic activities, we summarize here the catalytic properties of dinuclear and mononuclear copper species towards benzyl alcohol oxidation using a multivariate statistical approach. Here, the new dinuclear [Cu 2 (μ-L 1 )(μ-pz)] 2+ (1) is compared against the mononuclear [CuL 2 Cl] (2), where (L 1 ) - and (L 2 ) - are the respective deprotonated forms of 2,6-bis((bis(pyridin-2-ylmethyl)amino)methyl)-4-methylphenol, and 3-((bis(pyridin-2-ylmethyl)amino)methyl)-2-hydroxy-5-methylbenzaldehyde and (pz) - is a pyrazolato bridge. Copper(II) perchlorate (CP) is used as control. The catalytic oxidation of benzyl alcohol is pursued, aiming to assess the role of the ligand environment and nuclearity. The multivariate statistical approach allows for the search of optimal catalytic conditions, considering variables such as catalyst load, hydrogen peroxide load, and time. Species 1, 2 and CP promoted selective production of benzaldehyde at different yields, with only negligible amounts of benzoic acid. Under normalized conditions, 2 showed superior catalytic activity. This species is 3.5-fold more active than the monometallic control CP, and points out to the need for an efficient ligand framework. Species 2 is 6-fold more active than the dinuclear 1, and indicates the favored nuclearity for the conversion of alcohols into aldehydes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗