Carbon mass transfer in multimetallic systems containing potassium.
Carbon mass transfer reduction in multimetallic systems containing potassium
Engel, L. B., Jr.↗
SEARCH · Search NASA
Results for “MASS REDUCTION”
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.
Reflecting ablating heat shields for planetary entry.
Heat shielding for planetary entry probes of future Jovian and Venusian missions will encounter heating levels well beyond those previously experienced. These entries are typically dominated by radiative heating from the shock layer. This paper demonstrates the potential of reflecting this incident radiation diffusely from an ablating material. This technique contrasts with the absorption experienced by char-forming or graphitic ablators. Two dielectric materials, Teflon (polytetra-fluoroethylene) and boron nitride, are examined for their ablative performance, including reflection, in a combined convective- and radiative-heating environment. For Teflon, at the conditions obtained, superimposition of radiative heating upon a convective stream causes no additional increase in surface recession over the convective only results. For boron nitride, an excellent room-temperature reflector in the visible spectrum, a decrease in reflectivity from 90 to 55 percent is experienced when the surface undergoes sublimation at high temperatures. The process of reflection in each of these materials is described in terms of backscattering from crystals. The significance of a sizable reflection as a mode of energy accommodation is demonstrated for Venusian entries as a potential reduction in mass loss due to ablation.
Peterson, D. L.↗
Swirling flow of a dissociated gas
Most physical applications of the swirling flow, defined as a vortex superimposed on an axial flow in the nozzle, involve high temperatures and the possibility of real gas effects. The generalized one-dimensional swirling flow in a converging-diverging nozzle is analyzed for equilibrium and frozen dissociation using the ideal dissociating gas model. Numerical results are provided to illustrate the major effects and to compare with results obtained for a perfect gas with constant ratio of specific heats. It is found that, even in the case of real gases, perfect gas calculations can give a good estimate of the reduction in mass flow due to swirl.
Wolfram, W. R., Jr.↗
High pressure gas storage capacities. Example of a solution using filament windings
The use of epoxy resin fiber glass and economic factors affecting the choice of materials for gas storage are discussed. The physical nature of the filament windings are described together with the results obtained. It is demonstrated that a substantial reduction in mass and an enhanced level of safety can be assured at a competitive cost by storing gases in this way.
Phan, A.↗
Test and evaluation of the 2.4-micron photorefractor ocular screening system
An improved 2.4-m photorefractor ocular screening system was tested and evaluated. The photorefractor system works on the principal of obtaining a colored photograph of both human eyes; and, by analysis of the retinal reflex images, certain ocular defects can be detected such a refractive error, strabismus, and lens obstructions. The 2.4-m photorefractory system uses a 35-mm camera with a telephoto lens and an electronic flash attachment. Retinal reflex images obtained from the new 2.4-m system are significantly improved over earlier systems in image quality. Other features were also improved, notably portability and reduction in mass. A total of 706 school age children were photorefracted, 211 learning disabled and 495 middle school students. The total students having abnormal retinal reflexes were 156 or 22 percent, and 133 or 85 percent of the abnormal had refractive error indicated. Ophthalmological examination was performed on 60 of these students and refractive error was verified in 57 or 95 percent of those examined. The new 2.4-m system has a NASA patent pending and is authorized by the FDA. It provides a reliable means of rapidly screening the eyes of children and young adults for vision problems. It is especially useful for infants and other non-communicative children who cannot be screened by the more conventional methods such as the familiar E chart.
Richardson, J. R.↗
Optical information processing for NASA's space exploration
The development status of optical processing techniques under development at NASA-JPL, NASA-Ames, and NASA-Johnson, is evaluated with a view to their potential applications in future NASA planetary exploration missions. It is projected that such optical processing systems can yield major reductions in mass, volume, and power requirements relative to exclusively electronic systems of comparable processing capabilities. Attention is given to high-order neural networks for distortion-invariant classification and pattern recognition, multispectral imaging using an acoustooptic tunable filter, and an optical matrix processor for control problems.
Chao, Tien-Hsin↗
A deployable high temperature superconducting coil (DHTSC) - A novel concept for producing magnetic shields against both solar flare and Galactic radiation during manned interplanetary missions
The discovery of materials which are superconducting above 100 K makes possible the use of superconducting coils deployed beyong the hull of an interplanetary spacecraft to produce a magnetic shield capable of giving protection not only against solar flare radiation, but also even against Galactic radiation. Such deployed coils can be of very large size and can thus achieve the great magnetic moments required using only relatively low currents. Deployable high-temperature-superconducting coil magnetic shields appear to offer very substantial reductions in mass and energy compared to other concepts and could readily provide the radiation protection needed for a Mars mission or space colonies.
Cocks, F. Hadley↗
Nuclear power technology requirements for NASA exploration missions
It is pointed out that future exploration of the moon and Mars will mandate developments in many areas of technology. In particular, major advances will be required in planet surface power systems. Critical nuclear technology challenges that can enable strategic self-sufficiency, acceptable operational costs, and cost-effective space transportation goals for NASA exploration missions have been identified. Critical technologies for surface power systems include stationary and mobile nuclear reactor and radioisotope heat sources coupled to static and dynamic power conversion devices. These technologies can provide dramatic reductions in mass, leading to operational and transportation cost savings. Critical technologies for space transportation systems include nuclear thermal rocket and nuclear electric propulsion options, which present compelling concepts for significantly reducing mass, cost, or travel time required for Earth-Mars transport.
Bloomfield, Harvey S.↗
Recent advances in multidisciplinary optimization of rotorcraft
A joint activity involving NASA and Army researchers at NASA LaRC to develop optimization procedures to improve the rotor blade design process by integrating appropriate disciplines and accounting for all of the important interactions among the disciplines is described. The disciplines involved include rotor aerodynamics, rotor dynamics, rotor structures, airframe dynamics, and acoustics. The work is focused on combining these five key disciplines in an optimization procedure capable of designing a rotor system to satisfy multidisciplinary design requirements. Fundamental to the plan is a three-phased approach. In phase 1, the disciplines of blade dynamics, blade aerodynamics, and blade structure are closely coupled while acoustics and airframe dynamics are decoupled and are accounted for as effective constraints on the design for the first three disciplines. In phase 2, acoustics is integrated with the first three disciplines. Finally, in phase 3, airframe dynamics is integrated with the other four disciplines. Representative results from work performed to date are described. These include optimal placement of tuning masses for reduction of blade vibratory shear forces, integrated aerodynamic/dynamic optimization, and integrated aerodynamic/dynamic/structural optimization. Examples of validating procedures are described.
Adelman, Howard M.↗
Propellant production and useful materials: Hardware data from components and the systems
During the past year significant progress included: a major breakthrough in oxygen production through discs (instead of tubes) that resulted in two orders-of-magnitude increase in the yield rates, proving that oxygen production from any iron-bearing silicate (avoiding costly beneficiation) in lunar in-situ resource utilization (ISRU); construction of a half-scale robotic soil processor; production of melt-spun fibers in a solar furnace; and the culmination of first-stage research in the construction (and delivery to NASA LaRC) of a self-contained portable oxygen plant that incorporates the first generation ISRU technologies developed at UA SERC. In addition, further reductions in mass and power needs were achieved in two smaller oxygen plants, which, however, have far greater production rates. SERC continued to attract bright students both at the undergraduate and graduate levels, and several area high school students through the Professional Internship Program (PIP) administered by the local school district. Invited lectures at elementary schools continue to draw enthusiastic response. Another important first was the creation of the Freshman Colloquium, 'Space in Our Future, and Our Future in Space,' geared toward women and minority students. This course proved to be a success, with more than one-half of the enrollment composed of women. In recognition of these important contributions, the author was appointed to the NRC Committee on Space Science Technologies.
Ramohalli, Kumar↗
Recent advances in integrated multidisciplinary optimization of rotorcraft
A joint activity involving NASA and Army researchers at NASA LaRC to develop optimization procedures to improve the rotor blade design process by integrating appropriate disciplines and accounting for all of the important interactions among the disciplines is described. The disciplines involved include rotor aerodynamics, rotor dynamics, rotor structures, airframe dynamics, and acoustics. The work is focused on combining these five key disciplines in an optimization procedure capable of designing a rotor system to satisfy multidisciplinary design requirements. Fundamental to the plan is a three-phased approach. In phase 1, the disciplines of blade dynamics, blade aerodynamics, and blade structure are closely coupled while acoustics and airframe dynamics are decoupled and are accounted for as effective constraints on the design for the first three disciplines. In phase 2, acoustics is integrated with the first three disciplines. Finally, in phase 3, airframe dynamics is integrated with the other four disciplines. Representative results from work performed to date are described. These include optimal placement of tuning masses for reduction of blade vibratory shear forces, integrated aerodynamic/dynamic optimization, and integrated aerodynamic/dynamic/structural optimization. Examples of validating procedures are described.
Adelman, Howard M.↗
Space Power Requirements for Future NASA Missions
The key technology issues for the power requirements of future NASA space missions are: reduction in mass to enable smaller launch vehicles, faster trip time and lower cost; simpler more autonomous operations to reduce life cycle cost; reduce design, development , and qualification time to enable frequent low-cost missions; increase payload fraction and science return; enable next generation missions; stimulate U.S. industry to promote strong world leadership capability; and incorporate dual-use strategy into technology development.
Mulville, Daniel R.↗
An Overview of Future NASA Missions, Concepts, and Technologies Related to Imaging of the World's Land Areas
In the near term NASA is entering into the peak activity period of the Earth Observing System (EOS). The EOS AM-1 /"Terra" spacecraft is nearing launch and operation to be followed soon by the New Millennium Program (NMP) Earth Observing (EO-1) mission. Other missions related to land imaging and studies include EOS PM-1 mission, the Earth System Sciences Program (ESSP) Vegetation Canopy Lidar (VCL) mission, the EOS/IceSat mission. These missions involve clear advances in technologies and observational capability including improvements in multispectral imaging and other observing strategies, for example, "formation flying". Plans are underway to define the next era of EOS missions, commonly called "EOS Follow-on" or EOS II. The programmatic planning includes concepts that represent advances over the present Landsat-7 mission that concomitantly recognize the advances being made in land imaging within the private sector. The National Polar Orbiting Environmental Satellite Series (NPOESS) Preparatory Project (NPP) is an effort that will help to transition EOS medium resolution (herein meaning spatial resolutions near 500 meters), multispectral measurement capabilities such as represented by the EOS Moderate Resolution Imaging Spectroradiometer (MODIS) into the NPOESS operational series of satellites. Developments in Synthetic Aperture Radar (SAR) and passive microwave land observing capabilities are also proceeding. Beyond these efforts the Earth Science Enterprise Technology Strategy is embarking efforts to advance technologies in several basic areas: instruments, flight systems and operational capability, and information systems. In the case of instruments architectures will be examined that offer significant reductions in mass, volume, power and observational flexibility. For flight systems and operational capability, formation flying including calibration and data fusion, systems operation autonomy, and mechanical and electronic innovations that can reduce spacecraft and subsystem resource requirements. The efforts in information systems will include better approaches for linking multiple data sets, extracting and visualizing information, and improvements in collecting, compressing, transmitting, processing, distributing and archiving data from multiple platforms. Overall concepts such as sensor webs, constellations of observing systems, and rapid and tailored data availability and delivery to multiple users comprise and notions Earth Science Vision for the future.
Salomonson, Vincent V.↗
DTFM Modeling and Analysis Method for Gossamer Structures
Gossamer systems are mostly composed of support structures formed by highly flexible, long tubular elements and pre-tensioned thin-film membranes. These systems offer order-of-magnitude reductions in mass and launch volume and will revolutionize the architecture and design of space flight systems that require large in-orbit configurations and apertures. A great interest has been generated in recent years to fly gossamer systems on near-term and future space missions. Modeling and analysis requirements for gossamer structures are unique. Simulation of in-space performance issues of gossamer structures, such as inflation deployment of flexible booms, formation and effects of wrinkle in tensioned membranes, synthesis of tubular and membrane elements into a complete structural system, usually cannot be accomplished by using the general-purpose finite-element structural analysis codes. This has led to the need of structural modeling and analysis capabilities specifically suitable for gossamer structures. The Distributed Transfer Function Method (DTFM) can potentially meet this urgent need. Additional information is contained in the original extended abstract.
Fang, Hou-Fei↗
Cryogenic Propellant Long-Term Storage With Zero Boil-Off
Significant boil-off losses from cryogenic propellant storage systems in long-duration space mission applications result in additional propellant and larger tanks. The potential propellant mass loss reductions with the Zero Boil-off (ZBO) concept are substantial; therefore, further exploration through technology programs has been initiated within NASA. A large-scale demonstration of the ZBO concept has been devised utilizing the Marshall Space Flight Center (MSFC) Multipurpose Hydrogen Test Bed (MHTB) along with a cryo-cooler unit. The ZBO concept consists of an active cryo-cooling system integrated with traditional passive thermal insulation. The cryo-cooler is interfaced with the MHTB and spraybar recirculation/mixer system in a manner that enables thermal energy removal at a rate that equals the total tank heat leak. The liquid hydrogen (LH2) is withdrawn from the tank, passed through a heat exchanger, and then the chilled liquid is sprayed back into the tank through a spraybar. The test series will be performed over a 20-30 day period. Tests will be conducted at multiple fill levels to demonstrate concept viability and to provide benchmark data to be used in analytical model development. In this paper the test set-up and test procedures are presented.
Hedayat, Ali↗
A Method for Estimating Costs and Benefits of Space Assembly and Servicing By Astronauts and Robots
One aspect of designing future space missions is to determine whether Space Assembly and Servicing (SAS) is useful and, if so, what combination of robots and astronauts provides the most effective means of accomplishing it. Certain aspects of these choices, such as the societal value of developing the means for humans to live in space, do not lend themselves to quantification. However, other SAS costs and benefits can be quantified in a manner that can help select the most cost-effective SAS approach. Any space facility, whether it is assembled and serviced or not, entails an eventual replacement cost due to wear and obsolescence. Servicing can reduce this cost by limiting replacement to only failed or obsolete components. However, servicing systems, such as space robots, have their own logistics cost, and astronauts can have even greater logistics requirements. On the other hand, humans can be more capable than robots at performing dexterous and unstructured tasks, which can reduce logistics costs by allowing a reduction in mass of replacement components. Overall, the cost-effectiveness of astronaut SAS depends on its efficiency; and, if astronauts have to be wholly justified by their servicing usefulness, then the serviced space facility has to be large enough to fully occupy them.
Purves, Lloyd R.↗
Design and Characterization of Carbon Nanotube Nanocomposites
Revolutionary design concepts in future aerospace vehicles will depend on extraordinary material properties to permit significant reduction of mass and size of components, while imparting intelligence. Due to their combination of remarkable electrical and mechanical properties, carbon nanotubes (CNT) are expected to enable this paradigm shift in design concepts. However, significant challenges still exist in translating these CNT properties into the macrostructures required for future generations of aerospace vehicles. While an accepted route for making the leap from nanostructures to useful macrostructures has not been fully charted, this paper will give an overview of the approach taken by some researchers at NASA Langley Research Center to sort out issues involved in the development of CNT nanocomposites for multifunctional structures. Specifically, the dispersion of carbon nanotubes in polymer matrices, characterization of nanocomposites, the role of quantum computation in providing guidance for processing and the use of computational analysis in data interpretation will be covered. Significant improvements in mechanical and electrical properties of CNT nanocomposites with very low loadings of CNTs are described and lend credence to the potential for using CNTs in achieving technological leaps in composite development.
Siochi, Emilie J.↗
Materials trade study for lunar/gateway missions
The National Aeronautics and Space Administration (NASA) administrator has identified protection from radiation hazards as one of the two biggest problems of the agency with respect to human deep space missions. The intensity and strength of cosmic radiation in deep space makes this a 'must solve' problem for space missions. The Moon and two Earth-Moon Lagrange points near Moon are being proposed as hubs for deep space missions. The focus of this study is to identify approaches to protecting astronauts and habitats from adverse effects from space radiation both for single missions and multiple missions for career astronauts to these destinations. As the great cost of added radiation shielding is a potential limiting factor in deep space missions, reduction of mass, without compromising safety, is of paramount importance. The choice of material and selection of the crew profile play major roles in design and mission operations. Material trade studies in shield design over multi-segmented missions involving multiple work and living areas in the transport and duty phase of space mission's to two Earth-Moon co-linear Lagrange points (L1) between Earth and the Moon and (L2) on back side of the moon as seen from Earth, and to the Moon have been studied. It is found that, for single missions, current state-of-the-art knowledge of material provides adequate shielding. On the other hand, the choice of shield material is absolutely critical for career astronauts and revolutionary materials need to be developed for these missions. This study also provides a guide to the effectiveness of multifunctional materials in preparation for more detailed geometry studies in progress. c2003 COSPAR. Published by Elsevier Ltd. All rights reserved.
NASA Discipline Radiation Health↗