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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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS1979

A cesium TELEC experiment at Lewis Research Center

The thermoelectronic laser energy converter (TELEC), was studied as a method of converting a 10.6 mm CO2 laser beam into electric power. The calculated characteristics of a TELEC seem to be well matched to the requirements of a spacecraft laser energy conversion system. The TELEC is a high power density plasma device which absorbs an intense laser beam by inverse bremsstrahlung with the plasma electrons. In the TELEC process, electromagnetic radiation is absorbed directly in the plasma electrons producing a high electron temperature. The energetic electrons diffuse out of the plasma striking two electrodes which are in contact with the plasma at the boundaries. These two electrodes have different areas: the larger one is designated as the collector, the smaller one is designated as the emitter. The smaller electrode functions as an electron emitter to provide continuity of the current. Waste heat is rejected from the collector electrode. An experiment was carried out with a high power laser using a cesium vapor TELEC cell with 30 cm active length. Laser supported plasma was produced in the TELEC device during a number of laser runs over a period of several days. Electric power from the TELEC was observed with currents in the range of several amperes and output potentials of less than 1 volt. The magnitudes of these electric outputs were smaller than anticipated but consistent with the power levels of the laser during this experiment.

Britt, E. J.↗
NASA NTRS1992

HSCT integrated propulsion control issues

The propulsion control system affects the economics of the HSCT through the mechanisms indicated. Weight reduction is paramount in an aircraft of this type. Significant reductions are possible relative to the SST or even current technology if improvements are made in areas such as high temperature electronics. Dependability is an increasingly important parameter in all aircraft, but the higher capital cost of the HSCT makes it doubly important. Conversely the more difficult HSCT design problem makes it more difficult to achieve. Integration of propulsion controls will make it possible to improve both the static and dynamic performance of the HSCT propulsion system. Noise and emissions requirements may introduce novel control system requirements such as automatically programmed takeoff thrust for noise abatement. Control system development technology is evolving. For HSCT, highly automated and thoroughly validated tools will be required to reliably achieve desired system performance at introduction, and to reduce development costs. A technology plan was developed to prepare for HSCT development. This presentation addresses the portion of the plan required to demonstrate technology readiness for the HSCT in the late 1990's rather than the technology development currently in progress.

Carlin, Christopher M.↗
NASA NTRS2013

Sample Handling in Extreme Environments

Harsh environments, such as that on Venus, preclude the use of existing equipment for functions that involve interaction with the environment. The operating limitations of current high temperature electronics are well below the actual temperature and pressure found on Venus (460 deg C and 92 atm), so proposed lander configurations typically include a pressure vessel where the science instruments are kept at Earth-like temperature and pressure (25 deg C and 1 atm). The purpose of this project was to develop and demonstrate a method for sample transfer from an external drill to internal science instruments for a lander on Venus. The initial concepts were string and pneumatically driven systems; and the latter system was selected for its ability to deliver samples at very high speed. The pneumatic system was conceived to be driven by the pressure difference between the Venusian atmosphere and the inside of the lander. The pneumatic transfer of a small capsule was demonstrated, and velocity data was collected from the lab experiment. The sample transfer system was modeled using CAD software and prototyped using 3D printing. General structural and thermal analyses were performed to approximate the proposed system's mass and effects on the temperature and pressure inside of the lander. Additionally, a sampler breadboard for use on Titan was tested and functionality problems were resolved.

sample handling↗
NASA NTRS2000

Distorted Wave Calculation and Applications

Physical properties such as temperature and electron density of solar plasma and other astrophysical objects can be inferred from EUV and X-ray emission lines observed from space. These lines are emitted when the higher states of an ion are excited by electron impact and then decay by photon emission. Excitation cross sections are required for the spectroscopic analyses of the observations and various approximations have been used to calculate the scattering functions. One of them which has been widely used is a distorted wave approximation. This approximation, along with its applications to solar observations, is discussed. The Bowen fluorescence mechanism and optical depth effects are also discussed. It is concluded that such calculations are reliable for highly charged ions and for high electron temperatures.

Bhatia, A. K.↗
NASA NTRS2000

Distorted Wave Calculations and Applications

Physical properties such as temperature and electron density of solar plasma and other astrophysical objects can be inferred from EUV and X-ray emission lines observed from space. These lines are emitted when the higher states of an ion are excited by electron impact and then decay by photon emission. Excitation cross sections are required for the spectroscopic analyses of the observations and various approximations have been used to calculate the scattering functions. One of them which has been widely used is a distorted wave approximation. This approximation, along with its applications to solar observations, is discussed. The Bowen fluorescence mechanism and optical depth effects are also discussed. It is concluded that such calculations are reliable for highly charged ions and for high electron temperatures.

Bhatia, A. K.↗
NASA NTRS2020

Long-duration Venus lander for seismic and atmospheric science

An exciting and novel science mission concept called Seismic and Atmospheric Exploration of Venus (SAEVe) has been developed which uses high-temperature electronics to enable a three-order magnitude increase in expected surface life (120 Earth days) over what has been achieved to date. This enables study of long-term, variable phenomena such as the seismicity of Venus and near surface weather, near surface energy balance and atmospheric chemical composition. SAEVe also serves as a critical pathfinder for more sophisticated landers in the future. For example, first order seismic measurements by SAEVe will allow future missions to deliver better seismometers and systems to support the yet unknown frequency and magnitude of Venus events. SAEVe is focused on science that can be realized with low data volume instruments and will most benefit for temporal operations. The entire mission architecture and operations maximize science while minimizing energy usage and physical size and mass. The entire SAEVe system including its protective entry system is estimated to be around 45 kg and approximately 0.6 m diameter. These features allow SAEVe to be relatively cost effective and be easily integrated onto a Venus orbiter mission. The technologies needed to implement SAEVe are currently in development by several funded activities. Component and system level work is ongoing under NASA’s HOTTech program and by the Long Lived Insitu Solar System Explorer (LLISSE) project. The SAEVe long duration Venus lander promises groundbreaking science and is an ideal complimentary element to many future Venus orbiter missions being proposed or planned today.

Venus↗
NASA NTRS1976

Ionospheric composition in SAR-arcs

Theoretical ion and electron density profiles in the SAR-arc region are calculated using a model of the ionosphere based on the coupled continuity, momentum, and energy equations for O(+), NO(+), and O2(+). It is found that an increase in the reaction O(+) + N2 yields NO(+) + N, which results from enhanced N2 vibrational excitation due to the high electron temperatures found in SAR arcs, can cause a reduction in F-region electron densities by up to a factor of two. The increase in the O(+) + N2 reaction rate is shown to result in a marked change in the ion composition in SAR arcs, with NO(+) being an important ion up to altitudes of about 350 km at night. Since observed electron-density depressions in SAR arcs generally vary between factors of two and seven, it is concluded that the increase in the O(+) + N2 reaction rate cannot account for these depressions by itself.

Raitt, W. J.↗
NASA NTRS1977

Thermoelectronic laser energy conversion for power transmission in space

Long distance transmission of power in space by means of laser beams is an attractive concept because of the very narrow beam divergence. Such a system requires efficient means to both generate the laser beam and to convert the light energy in the beam into useful electric output at the receiver. A plasma-type device known as a Thermo-Electronic Laser Energy Converter (TELEC) has been studied as a method of converting a 10.6 micron CO2 laser beam into electric power. In the TELEC process, electromagnetic radiation is absorbed directly in the plasma electrons producing a high electron temperature. The energetic electrons diffuse out of the plasma striking two electrodes with different areas. Since more electrons are collected by the larger electrode there is a net transport of current, and an EMF is generated in the external circuit. The smaller electrode functions as an electron emitter to provide continuity of the current. Waste heat is rejected from the large electrode. A design for a TELEC system with an input 1 MW laser beam was developed as part of the study. The calculated performance of the system showed an overall efficiency of about 42%.

Britt, E. J.↗
NASA NTRS1978

The TELEC - A plasma type of direct energy converter

The Thermo-Electronic Laser Energy Converter (TELEC) is a high-power density plasma device designed to convert a 10.6-micron CO2 laser beam into electric power. Electromagnetic radiation is absorbed in plasma electrons, creating a high-electron temperature. Energetic electrons diffuse from the plasma and strike two electrodes having different areas. The larger electrode collects more electrons and there is a net transport of current. An electromagnetic field is generated in the external circuit. A computer program has been designed to analyze TELEC performance allowing parametric variation for optimization. Values are presented for TELEC performance as a function of cesium pressure and for current density and efficiency as a function of output voltage. Efficiency is shown to increase with pressure, reaching a maximum over 45%.

Britt, E. J.↗
NASA NTRS1980

Test of the inverse Compton model for Cygnus X-1

The unsaturated Compton model for Cygnus X-1 is attractive as it accounts for the power law spectrum with index (alpha) approximately equal to 1, and for the alleged high electron temperature (greater than 1 billion K). A critical test for the model is proposed, utilizing spectral data and especially the transition data when Cyg X-1 exhibited anticorrelated variations in soft and hard X-ray luminosities, with the pivoting point at about 10 keV; it is shown that the hard X-ray data available to date strongly support this model.

Liang, E. P. T.↗
NASA NTRS1981

High-temperature Complementary Metal Oxide Semiconductors (CMOS)

The results of an investigation into the possibility of using complementary metal oxide semiconductor (CMOS) technology for high temperature electronics are presented. A CMOS test chip was specifically developed as the test bed. This test chip incorporates CMOS transistors that have no gate protection diodes; these diodes are the major cause of leakage in commercial devices.

Mcbrayer, J. D.↗
NASA NTRS1983

The atmosphere of a dirty-clathrate cometary nucleus - A two-phase, multifluid model

The dynamical and thermal structure of a dirty-clathrate cometary nucleus' gas atmosphere is presently given a self-consistent, transonic multifluid solution in which, although the heavy neutron and ion species are treated as a single fluid in the collision-dominated region, the photoproduced H is treated separately. The thermal profile of the atmosphere thus obtained is entirely different from those predicted by the earlier, single-fluid models as well as the multifluid models which assumed equipartition of energy between electrons and ions. While the electron gas, like the neutrals and the ions, cools due to expansion, its main mode of energy loss in the inner coma is by way of inelastic collisions with the predominant H2O molecule. The high electron temperature in the outer coma also decreases the efficiency of electron removal by dissociative recombination, thereby increasing electron density throughout the coma.

Marconi, M. L.↗
NASA NTRS1987

Aeropropulsion 1987. Session 4: Instrumentation and Controls Research

The Lewis Research Center has had a long history of research directed toward advancing the national capability in the areas of propulsion research instrumentation and propulsion controls. Some of the major advances from this research that are currently in use are highlighted as well as some of the ongoing and planned research that will strongly impact the future capabilities. The presentations will cover the efforts on research instrumentation and controls as well as the research on high temperature electronics. This introductory section will focus on the major drivers or needs of the aeropropulsion industry that have shaped the instrumentation and controls research programs. Also covered will be the technological opportunities that have greatly impacted the program and that permitted break-throughs in several areas.

Source record↗
NASA NTRS1995

High-resolution measurements of the K-alpha spectra of low-ionizationm species of iron: A new spectral signature of nonequilibrium ionization conditions in young supernova remnants

We present the first systematic laboratory measurements of high-resolution K-alpha spectra of intermediate ions of iron, Fe X-XVII. These lines are not produced in collisional equilibrium plasmas because of the relevant charge states cannot exist at the high electron temperatures required for appreciable excitation of the K-alpha transitions. However, they can provide excellent spectral diagnostics for nonequilibrium ionization conditions, such the ionizing plasmas of young supernova remnants. To facilitate the line identifications, we compare our spectra with theoretical atomic calculations performed using multiconfiguration parametric potential and Dirac-Fock atomic codes. Our measurements also allow direct comparison with time-dependent ionization balance calculations for ionizing plasmas, and good agreement is found.

Decaux, V.↗
NASA NTRS2001

Thin Film Sensors for Surface Measurements

Advanced thin film sensors that can provide accurate surface temperature, strain, and heat flux measurements have been developed at NASA Glenn Research Center. These sensors provide minimally intrusive characterization of advanced propulsion materials and components in hostile, high-temperature environments as well as validation of propulsion system design codes. The sensors are designed for applications on different material systems and engine components for testing in engine simulation facilities. Thin film thermocouples and strain gauges for the measurement of surface temperature and strain have been demonstrated on metals, ceramics and advanced ceramic-based composites of various component configurations. Test environments have included both air-breathing and space propulsion-based engine and burner rig environments at surface temperatures up to 1100 C and under high gas flow and pressure conditions. The technologies developed for these sensors as well as for a thin film heat flux gauge have been integrated into a single multifunctional gauge for the simultaneous real-time measurement of surface temperature, strain, and heat flux. This is the first step toward the development of smart sensors with integrated signal conditioning and high temperature electronics that would have the capability to provide feedback to the operating system in real-time. A description of the fabrication process for the thin film sensors and multifunctional gauge will be provided. In addition, the material systems on which the sensors have been demonstrated, the test facilities and the results of the tests to-date will be described. Finally, the results will be provided of the current effort to demonstrate the capabilities of the multifunctional gauge.

Martin, Lisa C.↗
NASA NTRS2007

FPP [Floating Potential Probe] Results, Final Report

The Floating Potential Probe (FPP) operated on the International Space Station (ISS) from December 2000 to April 2001. During that time, it took many measurements of the ISS floating potential and the electron density and temperature. Those measurements were used as inputs to the Environments WorkBench (EWB) model of ISS potentials (originally developed by SAIC, but now sometimes called the Boeing model) that is used even today to predict charging levels for ISS. FPP is now completely defunct, having been removed and ejected from ISS. With the advent of the new Floating Potential Monitoring Unit (FPMU) on ISS, and the beginning of ISS operations with two large solar array panels instead of just one, a review of FPP measurements can offer comparisons with the new FPMU data and perhaps improve the accuracy of future ISS charging predictions. In particular, FPP measurements during times of low electron temperature and high electron density (the times of worst ISS charging) will be brought forward for comparison with the newly obtained FPMU data.

Ferguson, Dale C.↗
NASA NTRS2007

Concepts for Distributed Engine Control

Gas turbine engines for aero-propulsion systems are found to be highly optimized machines after over 70 years of development. Still, additional performance improvements are sought while reduction in the overall cost is increasingly a driving factor. Control systems play a vitally important part in these metrics but are severely constrained by the operating environment and the consequences of system failure. The considerable challenges facing future engine control system design have been investigated. A preliminary analysis has been conducted of the potential benefits of distributed control architecture when applied to aero-engines. In particular, reductions in size, weight, and cost of the control system are possible. NASA is conducting research to further explore these benefits, with emphasis on the particular benefits enabled by high temperature electronics and an open-systems approach to standardized communications interfaces.

Culley, Dennis E.↗