The Experts below are selected from a list of 243 Experts worldwide ranked by ideXlab platform
Shu T. Lai - One of the best experts on this subject based on the ideXlab platform.
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trapped photoelectrons during Spacecraft Charging in sunlight
IEEE Transactions on Plasma Science, 2015Co-Authors: Shu T. Lai, Kerri CahoyAbstract:For a dielectric Spacecraft Charging in sunlight, the potentials are different on the sunlit and dark sides. Differential Charging of Spacecraft surfaces can trap low-energy electrons by means of potential wells and barriers. The low-energy electrons are mostly photoelectrons and secondary electrons. Motivated by the recent interest in trapped photoelectrons measured by the Van Allen Probes in the radiation belts, we calculate the extent of the trapped photoelectron area and the potential barrier as a function of the dipole strength and sun angle using the monopole–dipole model. We find that the dipole strength is an important parameter in controlling the behavior of the potential wells and barriers. The usual inequality, $1/2 \le A \le 1$ where $A$ is the dipole strength, used in the monopole–dipole model can be relaxed and amended for finite sun angles. We then use a simple method to estimate the density of the trapped low-energy electrons in these areas. In sunlight Charging, the low-energy electron population around the Spacecraft is enhanced by the photoelectrons trapped inside the potential barrier.
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Trapped Photoelectrons During Spacecraft Charging in Sunlight
IEEE Transactions on Plasma Science, 2015Co-Authors: Shu T. Lai, Kerri CahoyAbstract:For a dielectric Spacecraft Charging in sunlight, the potentials are different on the sunlit and dark sides. Differential Charging of Spacecraft surfaces can trap low-energy electrons by means of potential wells and barriers. The low-energy electrons are mostly photoelectrons and secondary electrons. Motivated by the recent interest in trapped photoelectrons measured by the Van Allen Probes in the radiation belts, we calculate the extent of the trapped photoelectron area and the potential barrier as a function of the dipole strength and sun angle using the monopole- dipole model. We find that the dipole strength is an important parameter in controlling the behavior of the potential wells and barriers. The usual inequality, 1/2 ≤ A ≤ 1 where A is the dipole strength, used in the monopole-dipole model can be relaxed and amended for finite sun angles. We then use a simple method to estimate the density of the trapped low-energy electrons in these areas. In sunlight Charging, the low-energy electron population around the Spacecraft is enhanced by the photoelectrons trapped inside the potential barrier
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Spacecraft Charging: incoming and outgoing electrons
2013Co-Authors: Shu T. LaiAbstract:This paper presents an overview of the roles played by incoming and outgoing electrons in Spacecraft surface and stresses the importance of surface conditions for Spacecraft Charging. The balance between the incoming electron current from the ambient plasma and the outgoing currents of secondary electrons, backscattered electrons, and photoelectrons from the surfaces determines the surface potential. Since surface conditions significantly affect the outgoing currents, the critical temperature and the surface potential are also significantly affected. As a corollary, high level differential Charging of adjacent surfaces with very different surface conditions is a space hazard.
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Special Issue on Spacecraft Charging Technology 2013
IEEE Transactions on Plasma Science, 2013Co-Authors: Mengu Cho, Dale C. Ferguson, Shu T. Lai, David L. Cooke, Henry B. Garrett, Alain Hilgers, Jean-franois Roussel, Kazuhiro Toyoda, Adrian WheelockAbstract:The 34 papers in this special issue were originally presented at the 12th Spacecraft Charging Technology Conference, held in Kitakyushu, Japan in May of 2012.
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Special Issue on Spacecraft Charging Technology 2012
IEEE Transactions on Plasma Science, 2012Co-Authors: Mengu Cho, Dale C. Ferguson, Shu T. Lai, David L. Cooke, Henry B. Garrett, Alain Hilgers, Jean-françois Roussel, Adrian WheelockAbstract:The 32 papers in this special issue were originally presented at the 11th Spacecraft Charging Technology Conference. held in Albuquerque, NM, in September 2010.
Mengu Cho - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of Electron-emitting Film for Spacecraft Charging Mitigation (ELFs Charm)
TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES AEROSPACE TECHNOLOGY JAPAN, 2019Co-Authors: Atomu Tanaka, Kazuhiro Toyoda, Minoru Iwata, Jean-charles Mateo Velez, Sarah Dadouch, Teppei Okumura, Kenji Sakamoto, Mengu ChoAbstract:To protect a satellite from accidents due to Spacecraft Charging, Kyushu Institute of Technology (Kyutech) is developing a device called ELFs-Charm, which stands for ELectron-emitting Film for Spacecraft Charging Mitigation. Electron emission from ELFs-Charm was already confirmed in Polar Earth Orbit in 2012 via flight experiment onboard HORYU-II. As a next step, we are considering the practical operation for Spacecraft Charging mitigation. The present emission level is not enough to increase the satellite potential. We focus our efforts on improving two properties, Charging property and the emission threshold. The Charging property is measured by how well the differential voltage between the ELFs-charm insulator surface and the satellite chassis increases. The emission threshold is measured by the differential voltage when the electron emission starts. This paper reports the laboratory experimental results to measure the two properties of various samples. The sample made of fluorin resin coating had a good combination of the Charging property and the emission threshold that makes it possible to emit electron under realistic ambient electron current density in orbit.
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Guest Editorial Spacecraft Charging Technology
IEEE Transactions on Plasma Science, 2019Co-Authors: Allen Andersen, Dale C. Ferguson, Dennison, V. A. Davis, Michael Bodeau, Mengu Cho, M.m. Donegan, Nelson W. Green, Virginie Inguimbert, Insoo JunAbstract:This marks the seventh issue of the IEEE Transactions on Plasma Science dedicated to Spacecraft Charging Technology. The theme of this issue is based on the papers presented at the 15th Spacecraft Charging Technology Conference, Kobe, Japan, in 2018. The history of Spacecraft Charging goes back to the first Spacecraft Charging Technology Conference, sponsored by AFRL and NASA, that was held at the U.S. Air Force Academy, Colorado Springs, CO, USA, in 1978. The 15th Spacecraft Charging Technology Conference was hosted by the Japan Aerospace Exploration Agency (JAXA) and the Graduate School of System Informatics, Kobe University. It continues a tradition of international conferences on a ~2-year cycle. This conference, as well as each previous one in the series, was a great success. The topical discussions have greatly helped in making progress in the fields of Spacecraft Charging, Spacecraft-plasma interactions, and related areas. At the end of the 15th Conference, the assembly agreed to request publication of the proceedings of the conference in the IEEE Transactions on Plasma Science and to encourage the submission of the papers presented at the conference to the Journal.
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flight experiment results of electron emitting film for Spacecraft Charging mitigation
Journal of Spacecraft and Rockets, 2015Co-Authors: Naoki Matsumoto, Kazuhiro Toyoda, Minoru Iwata, Arifur R Khan, Atomu Tanaka, Mengu ChoAbstract:Spacecraft Charging poses a serious threat to satellite operation. An encounter with energetic electrons causes the Spacecraft potential to become highly negative. The potential difference between the Spacecraft’s chassis and the surface insulator can lead to an electrostatic discharge. If the negative potential of the satellite can be raised to near 0 V by emitting electrons from the satellite chassis, Spacecraft Charging can be mitigated. An electron-emitting film uses the electric field concentration near a triple junction and emits electrons in a completely passive manner. This emitter was mounted onboard the high-voltage technology demonstration satellite HORYU-II, a 30 cm cubical nanosatellite weighing 7.1 kg. HORYU-II was launched to a sun-synchronous orbit of 680 km altitude in May 2012. Experiments were conducted to measure the emission current from the emitter and the surface potential of an insulator similar to the emitter. Twenty-four trials were carried out over the aurora zone, mostly above ...
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Special Issue on Spacecraft Charging Technology 2013
IEEE Transactions on Plasma Science, 2013Co-Authors: Mengu Cho, Dale C. Ferguson, Shu T. Lai, David L. Cooke, Henry B. Garrett, Alain Hilgers, Jean-franois Roussel, Kazuhiro Toyoda, Adrian WheelockAbstract:The 34 papers in this special issue were originally presented at the 12th Spacecraft Charging Technology Conference, held in Kitakyushu, Japan in May of 2012.
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development of electron emitting film for Spacecraft Charging mitigation
Journal of Spacecraft and Rockets, 2012Co-Authors: Minoru Iwata, Mengu Cho, Kazuhiro Toyoda, Arifur R Khan, Hideyuki Igawa, Tatsuhito FujitaAbstract:Prevention of Spacecraft Charging and disCharging has become increasingly important as geostationary Earthorbit satellites employ higher bus voltages. There are numerous mitigation techniques against Spacecraft Charging, including electron emission from the Spacecraft chassis. A new electron emission device operating in a completely passive manner has been developed, which uses the field enhancement at the triple junction where the interface of metal and insulator is exposed to space. It has been named electron-emitting film for Spacecraft Charging mitigation (ELF’S CHARM). Microetching was applied to polyimide-copper laminated film to manufacture a laboratory prototype. This prototype ELFmaintains the emission current at the steady state from the triple junctions instead of leading to arcing. The electric field at the triple junction is macroscopically enhanced by Charging the polyimide film and microscopically by dielectric impurities on the copper surface. The laboratory experiments confirmed a stable current emission from 10 to 100 A for 4 hr from a 5-mm square sample having a 500m microetching pattern. Recently, the endurance of this ELF design has been confirmed by 100 hr of accumulated emission testing.
Dennison - One of the best experts on this subject based on the ideXlab platform.
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Guest Editorial Spacecraft Charging Technology
IEEE Transactions on Plasma Science, 2019Co-Authors: Allen Andersen, Dale C. Ferguson, Dennison, V. A. Davis, Michael Bodeau, Mengu Cho, M.m. Donegan, Nelson W. Green, Virginie Inguimbert, Insoo JunAbstract:This marks the seventh issue of the IEEE Transactions on Plasma Science dedicated to Spacecraft Charging Technology. The theme of this issue is based on the papers presented at the 15th Spacecraft Charging Technology Conference, Kobe, Japan, in 2018. The history of Spacecraft Charging goes back to the first Spacecraft Charging Technology Conference, sponsored by AFRL and NASA, that was held at the U.S. Air Force Academy, Colorado Springs, CO, USA, in 1978. The 15th Spacecraft Charging Technology Conference was hosted by the Japan Aerospace Exploration Agency (JAXA) and the Graduate School of System Informatics, Kobe University. It continues a tradition of international conferences on a ~2-year cycle. This conference, as well as each previous one in the series, was a great success. The topical discussions have greatly helped in making progress in the fields of Spacecraft Charging, Spacecraft-plasma interactions, and related areas. At the end of the 15th Conference, the assembly agreed to request publication of the proceedings of the conference in the IEEE Transactions on Plasma Science and to encourage the submission of the papers presented at the conference to the Journal.
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Methods for High Resistivity Measurements Related to Spacecraft-Charging
IEEE Transactions on Plasma Science, 2006Co-Authors: Dennison, Nelson W. Green, Prasanna Swaminathan, Jerilyn Brunson, A. R. FredericksonAbstract:A key parameter in modeling differential Spacecraft-Charging is the resistivity of insulating materials. This parameter determines how charge will accumulate and redistribute across the Spacecraft, as well as the timescale for charge transport and dissipation. American Society for Testing and Materials constant-voltage methods are shown to provide inaccurate resistivity measurements for materials with resistivities greater than ~1017 Omegamiddotcm or with long polarization decay times such as are found in many polymers. These data have been shown to often be inappropriate for Spacecraft-Charging applications and have been found to underestimate Charging effects by one to four orders of magnitude for many materials. The charge storage decay method is shown to be the preferred method to determine the resistivities of such highly insulating materials. A review is presented of methods to measure the resistivity of highly insulating materials-including the electrometer in resistance method, the electrometer in constant-voltage method, and the charge storage method. The different methods are found to be appropriate for different resistivity ranges and for different Charging circumstances. A simple macroscopic physics-based model of these methods allows separation of the polarization current and dark current components from long-duration measurements of resistivity over day- to month-long timescales. Model parameters are directly related to the magnitude of charge transfer and storage and the rate of charge transport. The model largely explains the observed differences in resistivity found using the different methods and provides a framework for recommendations for the appropriate test method for Spacecraft materials with different resistivities and applications
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Proposed Modifications to Engineering Design Guidelines Related to Resistivity Measurements and Spacecraft Charging
2005Co-Authors: Dennison, Nelson W. Green, Prasanna Swaminathan, Randy Jost, Jerilyn Brunson, A. Robb FredericksonAbstract:A key parameter in modeling differential Spacecraft Charging is the resistivity of insulating materials. This determines how charge will accumulate and redistribute across the Spacecraft, as well as the time scale for charge transport and dissipation. Existing Spacecraft Charging guidelines recommend use of tests and imported resistivity data from handbooks that are based principally upon ASTM methods that are more applicable to classical ground conditions and designed for problems associated with power loss through the dielectric, than for how long charge can be stored on an insulator. These data have been found to underestimate Charging effects by one to four orders of magnitude for Spacecraft Charging applications. A review is presented of methods to measure the resistive of highly insulating materials, including the electrometer-resistance method, the electrometer-constant voltage method, the voltage rate-of-change method and the charge storage method. This is based on joint experimental studies conducted at NASA Jet Propulsion Laboratory and Utah State University to investigate the charge storage method and its relation to Spacecraft Charging. The different methods are found to be appropriate for different resistivity ranges and for different Charging circumstances. A simple physics-based model of these methods allows separation of the polarization current and dark current components from long duration measurements of resistivity over day- to month-long time scales. Model parameters are directly related to the magnitude of charge transfer and storage and the rate of charge transport. The model largely explains the observed differences in resistivity found using the different methods and provides a framework for recommendations for the appropriate test method for Spacecraft materials with different resistivities and applications. The proposed changes to the existing engineering guidelines are intended to provide design engineers more appropriate methods for consideration and measurements of resistivity for many typical Spacecraft Charging scenarios.
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Effects of Evolving Surface Contamination on Spacecraft Charging
38th Aerospace Sciences Meeting and Exhibit, 2000Co-Authors: W. Y. Chang, Dennison, Jason Kite, R. E. DaviesAbstract:The effects of evolving surface contamination on Spacecraft Charging have been investigated through (i) ground-based measurements of the change in electron emission properties of a conducting surface undergoing contamination and (ii) modeling of the Charging of such surfaces using the NASCAP code. Specifically, we studied a Au surface as adsorbed species were removed and a very thin disordered carbon film was deposited as a result of exposure to an intense, normal incidence electron beam. As a result of this contamination, we found an ~50% decrease in secondary electron yield and an ~20% reduction in backscattered yield. The type and rates of contamination observed are similar to those encountered by operational Spacecraft. Charging potentials of an isolated panel of the material were determined under both sunlit and eclipse conditions in geosynchronous orbits for typical and extreme environments. In all environments studied, just monolayers of contamination lead to predictions of an abrupt threshold effect for Spacecraft Charging; panels that charged to small positive values when uncontaminated developed kilovolt negative potentials. The relative effect of NASCAP parameters for modeling secondary and backscattered electron emission and plasma electron distributions were also investigated. We conclude that surface contamination must be considered to avoid the serious detrimental effects associated with severe Spacecraft Charging.
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Instrumentation and Measurement of Secondary Electron Emission for Spacecraft Charging
2000Co-Authors: Neal Nickles, DennisonAbstract:Secondary electron emission is an important physical mechanism in the problem of Spacecraft Charging. The NASA Space Environments and Effects branch is currently revising NASA’s strategy for mitigating damage due to Spacecraft Charging. In an effort to substantially improve the modeling of Spacecraft Charging, measurements of secondary electron emission parameters are being made. The design of the apparatus needed to measure these parameters is discussed in detail. Various measurement techniques are explained and conclusions are drawn about the suitability of the final design.
V. A. Davis - One of the best experts on this subject based on the ideXlab platform.
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Guest Editorial Spacecraft Charging Technology
IEEE Transactions on Plasma Science, 2019Co-Authors: Allen Andersen, Dale C. Ferguson, Dennison, V. A. Davis, Michael Bodeau, Mengu Cho, M.m. Donegan, Nelson W. Green, Virginie Inguimbert, Insoo JunAbstract:This marks the seventh issue of the IEEE Transactions on Plasma Science dedicated to Spacecraft Charging Technology. The theme of this issue is based on the papers presented at the 15th Spacecraft Charging Technology Conference, Kobe, Japan, in 2018. The history of Spacecraft Charging goes back to the first Spacecraft Charging Technology Conference, sponsored by AFRL and NASA, that was held at the U.S. Air Force Academy, Colorado Springs, CO, USA, in 1978. The 15th Spacecraft Charging Technology Conference was hosted by the Japan Aerospace Exploration Agency (JAXA) and the Graduate School of System Informatics, Kobe University. It continues a tradition of international conferences on a ~2-year cycle. This conference, as well as each previous one in the series, was a great success. The topical discussions have greatly helped in making progress in the fields of Spacecraft Charging, Spacecraft-plasma interactions, and related areas. At the end of the 15th Conference, the assembly agreed to request publication of the proceedings of the conference in the IEEE Transactions on Plasma Science and to encourage the submission of the papers presented at the conference to the Journal.
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Spacecraft Charging Modeling -- Nascap-2k 2014 Annual Report
2014Co-Authors: V. A. Davis, M. J. MandellAbstract:Abstract : In support of the larger goal to provide a plasma engineering capability to the Spacecraft community, the objective of the Spacecraft Charging Modeling Nascap-2k contract is to develop, incorporate, test, and validate new algorithms for the three-dimensional plasma-environment Spacecraft interactions computational tool, Nascap-2k. Nascap-2k is being modified to extend the range of plasma physics phenomena that the code can simulate, make the advanced code capabilities more accessible to users, and improve and maintain both the graphical and non-graphical interfaces to the code. The upgraded code is being used to simulate problems of interest to AFRL. During the third year, Nascap-2k 4.1 was modified to be more user-friendly and address a wider array of Charging problems.
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The Best GEO Daytime Spacecraft Charging Index - Part II
52nd Aerospace Sciences Meeting, 2014Co-Authors: Dale Ferguson, V. A. Davis, Adrian WheelockAbstract:Ferguson and Wimberly, in 2013, reopened the debate on what is the best daytime GEO Spacecraft Charging index, by concentrating mainly on differential Charging, and by performing Nascap-2k simulations of Charging under different assumed environments. They concluded that the total thermal electron flux was the best Charging index of those formally proposed. In this paper, the authors attempt to verify the conclusions of the previous paper by comparing Nascap-2k results with Charging and fluxes measured on the SCATHA, Intelsat, DSCS, and LANL GEO satellites. In addition, because the net total thermal electron flux is dependent on the secondary electron emission from incident electrons below the second crossover point, which can be as high as several keV, a refined measure of Charging is presented as the total thermal electron flux above a certain energy that is well above the second crossover point. The use of this type of index will be justified by correlations between Nascap-2k simulation results and total fluxes above a range of energies. This approach is similar to those proposed previously in the interpretation of SCATHA and LANL results, and incorporated into the design of the DSCS satellites. The best minimum energy to use will be determined for Spacecraft of different design and surface materials. The use of sensors on Spacecraft that will allow measurement of the total flux above the optimal minimum energy will be discussed, along with in-situ Spacecraft potential monitors. In addition to aiding the design of flux and Charging monitors on succeeding Spacecraft generations, the results found here will be shown to point the way toward Spacecraft that will not arc even under severe GEO storm conditions. Finally, the optimum GEO daytime Spacecraft Charging index will be obtained, and its use for predicting and resolving Spacecraft anomalies in real time will be discussed.
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Nascap-2k Spacecraft Charging Code Overview
IEEE Transactions on Plasma Science, 2006Co-Authors: M. J. Mandell, V. A. Davis, David L. Cooke, Adrian Wheelock, C. J. RothAbstract:Nascap-2k is a modern Spacecraft Charging code, replacing the older codes NASA Charging Analyzer Program for GEosynchronous Orbit (NASCAP/GEO), NASA Charging Analyzer Program for Low-Earth Orbit (NASCAP/LEO), Potentials Of Large objects in the Auroral Region (POLAR), and Dynamic Plasma Analysis Code (DynaPAC). The code builds on the physical principles, mathematical algorithms, and user experience developed over three decades of Spacecraft Charging research. Capabilities include surface Charging in geosynchronous and interplanetary orbits, sheath, and wake structure, and current collection in low-Earth orbits, and auroral Charging. External potential structure and particle trajectories are computed using a finite element method on a nested grid structure and may be visualized within the Nascap-2k interface. Space charge can be treated either analytically, self-consistently with particle trajectories, or consistent with imported plume densities. Particle-in-cell (PIC) capabilities are available to study dynamic plasma effects. Auxiliary programs to Nascap-2k include Object Toolkit (for developing Spacecraft surface models) and GridTool (for constructing nested grid structures around Spacecraft models). The capabilities of the code are illustrated by way of four examples: Charging of a geostationary satellite, self-consistent potentials for a negative probe in a low-Earth orbit Spacecraft wake, potentials associated with thruster plumes, and PIC calculations of plasma effects on a very low frequency (about 1 to 20 kHz) antenna
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Characterization of Magnetospheric Spacecraft Charging Environments Using the LANL Magnetospheric Plasma Analyzer Data Set
2003Co-Authors: V. A. DavisAbstract:An improved specification of the plasma environment has been developed for use in modeling Spacecraft Charging. It was developed by statistically analyzing a large part of the LANL Magnetospheric Plasma Analyzer (MPA) data set for ion and electron spectral signature correlation with Spacecraft Charging, including anisotropies. The objective is to identify a relatively simple characterization of the full particle distributions that yield an accurate predication of the observed Charging under a wide variety of conditions.
Dale C. Ferguson - One of the best experts on this subject based on the ideXlab platform.
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Guest Editorial Spacecraft Charging Technology
IEEE Transactions on Plasma Science, 2019Co-Authors: Allen Andersen, Dale C. Ferguson, Dennison, V. A. Davis, Michael Bodeau, Mengu Cho, M.m. Donegan, Nelson W. Green, Virginie Inguimbert, Insoo JunAbstract:This marks the seventh issue of the IEEE Transactions on Plasma Science dedicated to Spacecraft Charging Technology. The theme of this issue is based on the papers presented at the 15th Spacecraft Charging Technology Conference, Kobe, Japan, in 2018. The history of Spacecraft Charging goes back to the first Spacecraft Charging Technology Conference, sponsored by AFRL and NASA, that was held at the U.S. Air Force Academy, Colorado Springs, CO, USA, in 1978. The 15th Spacecraft Charging Technology Conference was hosted by the Japan Aerospace Exploration Agency (JAXA) and the Graduate School of System Informatics, Kobe University. It continues a tradition of international conferences on a ~2-year cycle. This conference, as well as each previous one in the series, was a great success. The topical discussions have greatly helped in making progress in the fields of Spacecraft Charging, Spacecraft-plasma interactions, and related areas. At the end of the 15th Conference, the assembly agreed to request publication of the proceedings of the conference in the IEEE Transactions on Plasma Science and to encourage the submission of the papers presented at the conference to the Journal.
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best geosynchronous earth orbit daytime Spacecraft Charging index
Journal of Spacecraft and Rockets, 2015Co-Authors: Dale C. Ferguson, Robert V. Hilmer, Victoria A. DavisAbstract:Recently, the debate on what is the best daytime Geosynchronous Earth Orbit Spacecraft Charging index has been reopened. In this paper, the conclusions of one of the recent papers on the subject are verified by comparing Nascap-2k results with Charging and fluxes measured on the Spacecraft Charging at the High Altitudes, Intelsat, Defense Satellite Communications System, and Los Alamos National Laboratory Geosynchronous Earth Orbit satellites. In addition, a refined measure of Charging is presented as the total thermal electron flux above a certain minimum energy that is well above the second crossover point in secondary electron emission. The use of this type of index is justified by correlations between Nascap-2k simulation results and total fluxes above a range of energies. The best minimum energy to use is determined for Spacecraft of different design and surface materials. Finally, the optimum Geosynchronous Earth Orbit daytime Spacecraft Charging index is obtained, and its use for predicting and res...
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feasibility of detecting Spacecraft Charging and arcing by remote sensing
Journal of Spacecraft and Rockets, 2014Co-Authors: Dale C. Ferguson, Jeremy Murray Krezan, David A Barton, Stephen GregoryAbstract:More than 50 years after the dawn of the space age, most Spacecraft still do not have sensors onboard capable of detecting whether they are at potentials likely to put them at risk of severe Charging and the concomitant arcing, or, indeed, even capable of detecting when or if they undergo arcing. As a result, anomaly resolution has often been hit or miss, and false diagnoses are probably common. In this paper, a few remote sensing techniques that could be applied for remotely detecting Spacecraft Charging and/or arcing, and their feasibility, are examined: surface glows from high-energy electron impact, x-rays from bremsstrahlung, and radio and optical emission from arcs and after arcing.
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Special Issue on Spacecraft Charging Technology 2013
IEEE Transactions on Plasma Science, 2013Co-Authors: Mengu Cho, Dale C. Ferguson, Shu T. Lai, David L. Cooke, Henry B. Garrett, Alain Hilgers, Jean-franois Roussel, Kazuhiro Toyoda, Adrian WheelockAbstract:The 34 papers in this special issue were originally presented at the 12th Spacecraft Charging Technology Conference, held in Kitakyushu, Japan in May of 2012.
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new frontiers in Spacecraft Charging
IEEE Transactions on Plasma Science, 2012Co-Authors: Dale C. FergusonAbstract:Spacecraft Charging, as a field, is continually being recharged by new developments in understanding, new materials and technologies, and new approaches to both new and old problems. I will discuss some of the new frontiers in understanding Spacecraft Charging in this paper, as well as referencing relevant papers from the 11th Spacecraft Charging Technology Conference. Spacecraft Charging is highly material-property dependent. For example, the secondary electron emission, photoemission, bulk electrical resistivity, and surface resistivity are important parameters that help determine the extent of Spacecraft Charging (both on the surface and inside the Spacecraft) in any given environment. Our understanding of these material properties is one of the new frontiers in Spacecraft Charging. I will discuss how these fundamental material properties have been found to depend on the following: proper measurement techniques, temperature, radiation flux, electric field, surface treatment, surface contamination from plumes and outgassing, surface modification through arcing and vacuum exposure, and synergistic effects. Modeling of Spacecraft Charging is a second new frontier. New developments in modeling have both improved our understanding of Spacecraft Charging and enabled us to model situations that are dynamic and geometrically complex. New schemes for treating both space and time variations of fields, particle fluxes, and spectra have made our modeling more precise and accurate. Now, many more Spacecraft are being launched into low Earth orbit and the radiation belts. Modeling Charging effects more accurately in those orbits will become more important than ever. A third new frontier in Spacecraft Charging is novel mitigation techniques. Surface materials and simple passive devices that emit electrons as fast as they are collected seem to make real-time charge mitigation cheaply and reliably achievable for the first time. Novel solar cell configurations and coverglass materials promise to make arcing, both of the primary electrostatic discharge (ESD) type and sustained arcing between cells or strings, a thing of the past. Superconducting cables may obviate the high voltages that lead to arcing. New cooperation between Spacecraft and solar array manufacturers and Spacecraft Charging experts may help to prevent the Spacecraft Charging mistakes of the past. Furthermore, the final frontier is dealing with new materials and higher power requirements. Lightweight Spacecraft materials are, in some cases, prone to exacerbate Charging or arcing and may allow transmission of electromagnetic interference into sensitive electronics. New solar cell active materials may increase the effects of arcing on solar cell and solar array performance, even for primary ESD events. Higher power requirements may require longer transmission cables, which may increase the need for higher voltages, making arcing more likely. If superconducting cables become a reality, magnetics may become very important for Spacecraft control and stability. What will happen to a superconducting cable if it must carry the increased current in an arcing event of very short duration?