Download or read book A Novel Numerical Analysis of Hall Effect Thruster and Its Application in Simultaneous Design of Thruster and Optimal Low thrust Trajectory written by Kybeom Kwon and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Hall Effect Thrusters (HETs) are a form of electric propulsion device which uses external electrical energy to produce thrust. When compared to various other electric propulsion devices, HETs are excellent candidates for future orbit transfer and interplanetary missions due to their relatively simple configuration, moderate thrust capability, higher thrust to power ratio, and lower thruster mass to power ratio. Due to the short history of HETs, the current design process of a new HET is a largely empirical and experimental science, and this has resulted in previous designs being developed in a narrow design space based on experimental data without systematic investigations of parameter correlations. In addition, current preliminary low-thrust trajectory optimizations, due to inherent difficulties in solution procedure, often assume constant or linear performances with available power in their applications of electric thrusters. The main obstacles come from the complex physics involved in HET technology and relatively small amounts of experimental data. Although physical theories and numerical simulations can provide a valuable tool for design space exploration at the inception of a new HET design and preliminary low-thrust trajectory optimization, the complex physics makes theoretical and numerical solutions difficult to obtain. Numerical implementations have been quite extensively conducted in the last two decades. An investigation of current methodologies reveals that to date, none provide a proper methodology for a new HET design at the conceptual design stage and the coupled low-thrust trajectory optimization. Thus, in the first half of this work, an efficient, robust, and self-consistent numerical method for the analysis of HETs is developed with a new approach. The key idea is to divide the analysis region into two regions in terms of electron dynamics based on physical intuition. Intensive validations are conducted for existing HETs from 1 kW to 50 kW classes. The second half of this work aims to construct a simultaneous design optimization environment though collaboration with experts in low-thrust trajectory optimization where a new HET and associated optimal low-thrust trajectory can be designed simultaneously. A demonstration for an orbit raising mission shows that the constructed simultaneous design optimization environment can be used effectively and synergistically for space missions involving HETs. It is expected that the present work will aid and ease the current expensive experimental HET design process and reduce preliminary space mission design cycles involving HETs.

Download or read book Fundamentals of Electric Propulsion written by Dan M. Goebel and published by John Wiley & Sons. This book was released on 2008-12-22 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: Throughout most of the twentieth century, electric propulsion was considered the technology of the future. Now, the future has arrived. This important new book explains the fundamentals of electric propulsion for spacecraft and describes in detail the physics and characteristics of the two major electric thrusters in use today, ion and Hall thrusters. The authors provide an introduction to plasma physics in order to allow readers to understand the models and derivations used in determining electric thruster performance. They then go on to present detailed explanations of: Thruster principles Ion thruster plasma generators and accelerator grids Hollow cathodes Hall thrusters Ion and Hall thruster plumes Flight ion and Hall thrusters Based largely on research and development performed at the Jet Propulsion Laboratory (JPL) and complemented with scores of tables, figures, homework problems, and references, Fundamentals of Electric Propulsion: Ion and Hall Thrusters is an indispensable textbook for advanced undergraduate and graduate students who are preparing to enter the aerospace industry. It also serves as an equally valuable resource for professional engineers already at work in the field.

Download or read book Arcjet Plasma Neutralization of Hall Thrusters I Hybrid Thruster Mission Analysis written by and published by . This book was released on 2003 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Clustering multiple thrusters has emerged as a favored option for extending Hall effect thruster propulsion to very high powers (100-150 kW) for a variety of Air Force missions. However, there are inherent difficulties in the simultaneous neutralization of several Hall effect thrusters. Chief among these is the issue of unequal current sharing among multiple cathodes. For this reason, it may prove advantageous to use a single, high current neutralizer. Conventional Hall effect thruster neutralizers, hollow cathodes, typically consume 10% of the propellant flow and produce little or no thrust. An arcjet is an electro-thermal electric thruster with moderate efficiency and specific impulse ranges. It is also a high plasma density device that is capable of supporting and amplifying electron current through volume ionization and is capable of neutralizing single or clusters of Hall effect thrusters. By using an arcjet as a neutralizer, Hall effect thrusters will also produce useful thrust from their neutralizers. Because of the arcjet's lower specific impulse, the hybrid arcjet-Hall system will have a lower specific impulse than that of a pure Hall effect system. However by choosing suitable propellants, the hybrid Hall cluster will retain the high thrust efficiencies typical of pure Hall effect systems with the added benefit of lower total wet mass for select missions due to a higher system thrust density. This work examines the application of an arcjet-neutralized cluster of Hall effect thrusters for a low earth orbit to geosynchronous orbit transfer. The analysis shows that hybrid Hall effect clusters neutralized by a single medium power arcjet are advantageous for some orbit raising missions. Helium arcjet-neutralizers coupled with conventional xenon Hall effect anodes appear to he the superior configuration due to their relatively high efficiencies and low tankage fractions when compared to alternative propellant mixes.

Download or read book Analytical and Numerical Study of a Hall Effect Thruster with a Particle in cell Model written by Alejandro Benítez Martín and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Space propulsion, and more specifically electric propulsion, has been growing widely strong for the last 20 years thanks to the increasingly frequent technological advances in this field. That's why there are plenty of studies arising seeking for new ways of computing simulations of propulsion systems. This is the case of the Particle-in-Cell method. This method is nowhere near new, for it started being used in the 1950s, but the computational advances in the recent years have opened new doors for this numerical method that makes it one of the best options. So, this thesis has the main purpose of proving that Particle-in-Cell simulations of a onedimensional Hall-effect thruster channel give similar results to experimental data obtained via analytical models. For it, first an introduction to different electric propulsion systems and plasma physics will be done in order to have the basis of Hall thrusters functioning so the analysis can be performed. Once the basis are settled, the analytical model will be performed comparing the results with those obtained by professor E. Ahedo and then, using the results obtained in the analytical model as reference, the numerical model using the PIC method will be computed. Finally, by discussing and comparing the two models, we will see that the results obtained in both models resemble a lot those obtained by professor E. Ahedo and the experimental data from real life thrusters, with the only difference that some discrepancies appear. In the case of the analytical model, values in electrons temperature will tend to have a sudden decrease due to not taking into account wall losses and plume divergence, while in the PIC numerical model a little oscillation appears at the beginning due to the finite difference solver used. Although the appearance of such discrepancies, the results obtained are exactly the ones that were expected, hence proving the viability of the PIC model for plasma computation.

Download or read book A Small Modular Laboratory Hall Effect Thruster written by Ty Davis Lee and published by . This book was released on 2014 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electric propulsion technologies promise to revolutionize access to space, opening the door for mission concepts unfeasible by traditional propulsion methods alone. The Hall effect thruster is a relatively high thrust, moderate specific impulse electric propulsion device that belongs to the class of electrostatic thrusters. Hall effect thrusters benefit from an extensive flight history, and offer significant performance and cost advantages when compared to other forms of electric propulsion. Ongoing research on these devices includes the investigation of mechanisms that tend to decrease overall thruster efficiency, as well as the development of new techniques to extend operational lifetimes. This thesis is primarily concerned with the design and construction of a Small Modular Laboratory Hall Effect Thruster (SMLHET), and its operation on argon propellant gas. Particular attention was addressed at low-cost, modular design principles, that would facilitate simple replacement and modification of key thruster parts such as the magnetic circuit and discharge channel. This capability is intended to facilitate future studies of device physics such as anomalous electron transport and magnetic shielding of the channel walls, that have an impact on thruster performance and life. Preliminary results demonstrate SMLHET running on argon in a manner characteristic of Hall effect thrusters, additionally a power balance method was utilized to estimate thruster performance. It is expected that future thruster studies utilizing heavier though more expensive gases like xenon or krypton, will observe increased efficiency and stability.

Download or read book Performance Evaluation of the SPT 140 written by and published by . This book was released on 1997 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development of an Annular Micro Hall effect Thruster and Halbach Permanent Magnet Arrays in Hall effect Thrusters written by Matthew Warren and published by . This book was released on 2018 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: The research following began the initial steps in developing a micro-Hall-effect thruster for the use on a University of Alabama designed and built CubeSat. Additionally, the implementation of an asymmetric magnetic field utilizing a Halbach array of permanent magnets was computationally modelled and constructed. Facilities to support this research we're not available at UA at the beginning of this effort, and were developed over the course of the research. Results of the magnetic computational models found a large difference in the magnetic fields of the MHET ring magnet and Halbach array designs. The UA MHET ring magnet was successfully operated for a combined 20 hours of testing, at a range of 5 to 50 W of power over varying voltages and mass flows. Additionally, two ion current sweeps were taken using a Faraday probe and the data analyzed, with the result that the design that was swept was not magnetically correct and would need to be solved before continuing testing. With a new design constructed, testing will continue to verify the magnetic field is correct and a nominal ion current sweep is achieved. Additionally, the operational window for the design, the lifetime, and thrust must all be tested before a thruster can be deemed flight ready for a UA CubeSat. Additionally, the Halbach array variant should also be tested and compared to the ring magnet design to look for novel operation and potentially useful results to implement into future Hall-effect thruster designs.

Download or read book Magnetic Shielding Topology Applied to Low Power Hall Thrusters written by Lou Grimaud and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hall thrusters are one of the most used rocket electric propulsion technology. They combine moderate specific impulse with high thrust to power ratio which makes them ideal for a wide range of practical commercial and scientific applications. One of their limitations is the erosion of the thruster walls which reduces their lifespan.The magnetic shielding topology is a proposed solution to prolong the lifespan. It is implemented on a small200W Hall thruster.In this thesis the scaling of classical unshielded Hall thrusters down to 200 and 100W is discussed. A 200W low power magnetically shielded Hall thruster is compared with an identically sized unshielded one. The ion behavior inside the thruster is measured and significant differences are found across the discharge channel.Both thrusters are tested with classical BN-SiO2 and graphite walls. The magnetically shielded thruster is not sensitive to the material change while the discharge current increase by 25% in the unshielded one. The result is a maximum efficiency of 38% for boron nitride in the unshielded thruster but only 31% with graphite.The shielded thruster achieves a significantly lower efficiency with only 25% efficiency with both materials.Analysis of the experimental results as well as simulations of the thrusters reveal that the performance difference is mostly caused by low propellant utilization. This low propellant utilization comes from the fact that the ionization region doesn't cover all of the discharge channel. A new magnetically shielded thruster is designed to solve this issue.

Download or read book International Aerospace Abstracts written by and published by . This book was released on 1997 with total page 940 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Performance Characterization of a Three axis Hall Effect Thruster written by Spencer E. Temkin and published by . This book was released on 2010 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Low Power Magnetically Shielded Hall Thrusters written by Ryan Conversano and published by . This book was released on 2015 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents an investigation of the applicability of magnetic shielding to low-power Hall thrusters as a means to significantly improve operational lifetime. The key life-limiting factors of conventional Hall thrusters, including ion-bombardment sputter erosion of the discharge channel and high-energy electron power deposition to the channel walls, have been investigated extensively for a wide range of thruster scales. As thruster power is reduced to the "miniature" (i.e. sub-500 W) power regime, the increased surface-to-volume ratio of the discharge channel and decreased thruster component sizes promotes increased plasma-wall interactions and susceptibility to overheating, thereby reducing thruster operational lifetime and performance. Although methods for compensating for these issues have been investigated, unshielded miniature Hall thrusters are generally limited to sub-45% anode efficiencies and maximum lifetimes on the order of 1,000 h. A magnetically shielded magnetic field topology aims to maintain a low electron temperature along the channel surfaces and a plasma potential near that of the discharge voltage along the entire surface of the discharge channel along its axial length. These features result in a reduction of the kinetic energy of ions that impact the channel surfaces to near to or below the sputtering threshold, thus preventing significant ion-bombardment erosion of the discharge channel. Improved confinement of high-energy electrons is another byproduct of the field structure, aiding in the reduction of electron power deposition to the channel. Magnetic shielding has been shown to dramatically reduce plasma-wall interactions on 4 - 6 kW Hall thrusters, resulting in significant increases in projected operational lifetimes with minimal effects to thruster performance. In an effort to explore the scalability of magnetic shielding to low-power devices, two magnetically shielded miniature Hall thrusters were designed, fabricated and tested. The performance of the first thruster, called the MaSMi 40, was characterized at an operating condition of 275 V and 325 W. A peak thrust of approximately 13 mN with a specific impulse of approximately 1,100 s at an anode efficiency of approximately 22% were measured at the nominal operating point. Observations of the near exit plasma discharge during operation, and the discharge channel after operation, suggested that the outer channel wall of the thruster was well shielded from ion bombardment while the inner channel wall appeared to be weakly shielded. Further analysis concluded that the MaSMi-40 generated a partially-magnetically shielded field topology. However, the shortcomings of the MaSMi-40's magnetic circuit design were investigated in detail and are now well understood. The second design iteration in the development of a low-power magnetically shielded Hall thruster was the MaSMi-60. Magnetic field measurements confirmed that a symmetric and fully shielded magnetic field topology was generated by this device across a wide range of possible operating conditions. At operating powers of 160 W to nearly 750 W, the key performance metrics of the MaSMi-60 included a measured thrust ranging from approximately 8 mN to over 33 mN with anode specific impulses of up to approximately 1370 s at anode efficiencies of over 28%. Downstream plume measurements identified the primary factors contributing to the low anode efficiency. Visual observations of the discharge plasma and channel walls during and after thruster operation offered strong evidence of magnetic shielding. Erosion rates of the channel were approximated using carbon backsputter measurements; the results suggested a 10x - 100x decrease in wall erosion compared to unshielded Hall thrusters, corresponding to an equal increase in discharge channel lifetime compared to conventional miniature unshielded Hall thrusters. The physics and behaviors of the MaSMi-60's plasma discharge upstream of and in the near-field of the thruster exit plane were investigated using Hall2De, the 2-D axisymmetric code developed at the Jet Propulsion Laboratory for the simulation of the partially ionized plasma in Hall thrusters. Simulations of the MaSMi-60 suggested that the thruster achieved the plasma properties required for effective magnetic shielding, including low electron temperatures and a near-constant plasma potential along the channel walls. This was the final piece of evidence suggesting that magnetic shielding was attained at the miniature scale. The experimentally measured performance of the MaSMi-60 was captured by the Hall2De model, offering physical explanations for the low measured anode efficiency and leading to suggestions for improving the performance in future design iterations.

Download or read book Hall Effect Thruster Ground Testing Challenges written by and published by . This book was released on 2009 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper presents the challenges in the ground testing of Hall effect thrusters for plasma spacecraft propulsion applications. Hall effect thrusters by virtue of their high specific impulse can reduce spacecraft station-keeping propulsion mass by as much as an order of magnitude. However, testing and qualifying such plasma propulsion systems for use on spacecraft has a number of challenges. These challenges include the need for simulating the space environment, measuring very low thrust levels, determining lifetime, and under-standing the interaction of the energetic plume with spacecraft surfaces. Overcoming these challenges requires the use of both measurements and simulations of the complex plasma- surface interactions. It is only through the combined use of test and measurement resources that these plasma thrusters can be adequately characterized for on orbit qualification.

Download or read book DESIGN DEVELOPMENT AND TESTING OF AN INVERTED PENDULUM THRUST STAND FOR LOW POWER HALL EFFECT THRUSTERS written by and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract : This paper covers the design, development, and testing of a null-type inverted pendulum thrust stand intended to measure the thrust of a low-power Hall-effect thruster. The calibration system and control algorithm are described along with the atmosphere testing conducted prior to testing in vacuum. This thrust stand was tested in vacuum with an Aurora Hall-effect thruster, and the performance of the calibration procedure, control loops, and thrust drift were evaluated. The thrust stand showed a relative calibration uncertainty of 1.242%. The overall uncertainty of the thrust measurement at a nominal 19 mN operating point was shown to be 0.411 mN, or 2.16%. Temperature was proven to be a large factor in stable-power thrust drift.

Download or read book Numerical Study of Current Driven Instabilities and Anomalous Electron Transport in Hall effect Thrusters written by Jonathan Tran and published by . This book was released on 2017 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plasma turbulence and the resulting anomalous electron transport due to azimuthal current driven instabilities in Hall-effect thrusters is a promising candidate for developing predictive models for the observed anomalous transport. A theory for anomalous electron transport and current driven instabilities has been recently studied by [Lafluer et al., 2016a]. Due to the extreme cost of fully resolving the Debye length and plasma frequency, hybrid plasma simulations utilizing kinetic ions and quasi-steady state fluid electrons have long been the principle workhorse methodology for Hall-effect thruster modeling. Using a reduced dimension particle in cell simulation implemented in the Thermophysics Universal Research Framework developed by the Air Force Research Lab, we show collective electron-wave scattering due to large amplitude azimuthal fluctuations of the electric field and the plasma density. These high-frequency and short wavelength fluctuations can lead to an effective cross-field mobility many orders of magnitude larger than what is expected from classical electron-neutral momentum collisions in the low neutral density regime. We further adapt the previous study by [Lampe et al., 1971] and [Stringer, 1964] for related current driven instabilities to electric propulsion relevant mass ratios and conditions. Finally, we conduct a preliminary study of resolving this instability with a modified hybrid simulation with the hope of integration with established hybrid Hall-effect thruster simulations.

Download or read book NASA s Hall Thruster Program written by Robert S. Jankovsky and published by . This book was released on 2001 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development of a Low power Hall Effect Thruster written by John William Walter and published by . This book was released on 2000 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of a Hall Effect Thruster Using Thermal Imaging written by James William Tomaszewski and published by . This book was released on 2007 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: