- Author : Renato Krpoun
- Publisher : Unknown
- Release Date : 2009
- Genre: Uncategoriezed
- Pages : 133
- ISBN 10 : OCLC:428225382
Micromachined Electrospray Thrusters for Spacecraft Propulsion 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.
Spacecraft missions require a simple, high performing and highly reliable propulsion system to meet performance requirements. Unlike many other types of spacecraft thrusters, electrospray devices can be successful in a variety of propulsion applications. Due to their small size and flexible form factor, electrosprays are well-suited for primary propulsion, attitude control and formation flying. Electrospray Thrusters for Spacecraft Propulsion: Fundamentals and Technology covers the fundamentals and underlying physics of electrosprays and how they are used in controlling thruster performance. The book begins with a historical overview exploring how this technology has been rapidly growing with the emergence of small satellites and CubeSats. It covers a variety of topics such as electrospray plumes, interfacing with the spacecraft, dual propulsion, fluid feed systems, hybrid concepts, and future developments. This book is for aerospace and mechanical engineers, researchers, and advanced students taking electric propulsion courses. Provides a comprehensive understanding of the physical implementations, past failures, and current working implementations of electrosprays Discusses the origins of electrospray technology, the historical hurdles, and directions in which the technology is moving Features an up-to-date description of existing thruster/spacecraft interface and interaction with spacecraft
The standardization of small spacecraft through CubeSats has allowed for more affordable space exploration. This progress in affordability has been limited to Earth orbit due in part to the lack of high [delta]V propulsion systems that are compatible with the small form factor. The ion Electrospray Propulsion System developed at the Space Propulsion Laboratory at the Massachusetts Institute of Technology is a promising technology foundation for a compact, high [delta]V propulsion system. However, the [delta]V output of the propulsion system is limited by the lifetime of individual electrospray thrusters. This thesis presents the design and analysis of a stage-based concept for the ion Electrospray Propulsion System where the propulsion system is composed of a stack of electrospray thruster arrays. The stage-based propulsion system bypasses the lifetime limit of individual electrospray thrusters in order to increase the lifetime of the entire propulsion system. In effect, propulsion capabilities for CubeSats can be advanced without the need for technological developments. With the current performance metrics of the ion Electrospray Propulsion System, deep-space missions with an initial spacecraft form factor of a 3U CubeSat are feasible with current propulsion technology. Mechanisms required for the stage-based system are designed and demonstrated in a vacuum environment. In addition, analytical methodologies for the analysis of stage-based propulsion systems are developed to assist in preliminary mission design as well as provide the framework for autonomous decision making. Finally, applications of a stage-based propulsion system for missions to near-Earth asteroids are explored as well as analytical guidance for the escape trajectory.
Space Micropropulsion for Nanosatellites: Progress, Challenges and Future features the latest developments and progress, the challenges faced by different researchers, and insights on future micropropulsion systems. Nanosatellites, in particular cubesats, are an effective test bed for new technologies in outer space. However, most of the nanosatellites have no propulsion system, which subsequently limits their maneuverability in space. Explains why nanosatellite requirements need unique micro-technologies to help develop a compliant propulsion system Features an overview of nanosatellites and the global nanosatellite market Covers chemical and electric micropropulsion and the latest developments
High specific impulse electric propulsion systems enable ambitious lunar and interplanetary missions that return a wealth of scientific data. Many of these technologies are difficult to scale down, meaning the spacecraft are relatively massive and expensive. The Space Propulsion Lab (SPL) at the Massachusetts Institute of Technology (MIT) is developing compact, high specific impulse ion electrospray thrusters which do not suffer from the same sizing limitations. The Ion Electrospray Propulsion System (iEPS) is tailored for small spacecraft and can perform high AV maneuvers. This enables a plethora of lunar and interplanetary missions using nanosatellites, which can lead to substantial cost reductions. The main objective of the research presented in this thesis is to develop a guidance and control (GC) architecture for small spacecraft using iEPS modules for main propulsion and attitude control actuation and to evaluate its performance through simulation. The Lunar Impactor mission serves as the primary case study, and the results offer valuable insight into the design of the propulsion system while validating the functionality of the GC algorithm. These methods are extended in a second case study focusing on exploration of a near-earth asteroid.
"This dissertation presents work on development of multi-mode specific spacecraft propulsion systems. Specifically, this work attempts to realize a single propellant capable of both chemical monopropellant and electric electrospray rocket propulsion, develop methods to characterize multi-mode propulsion system performance, and realize a system capable of both monopropellant and electrospray propulsion for a small spacecraft. Selection criteria for ionic liquid propellants capable of both monopropellant and electrospray propulsion are developed. These are based on desired physical properties and performance considering use in both propulsive modes. From these insights, a monopropellant mixture of 1-ethyl-3-methylimidazolium ethyl sulfate and hydroxylammonium nitrate is selected and synthesized. Multi-mode spacecraft micropropulsion systems which include a high-thrust chemical mode and high-specific impulse electric mode are assessed. Due to the combination of a common propellant for both propulsive modes, low inert mass, and high electric thrust, the monopropellant/electrospray system has the highest mission capability in terms of delta-V for missions lasting shorter than 150 days. The ionic liquid monopropellant mixture is tested for decomposition on heated platinum, rhenium, and titanium surfaces. It was found that the propellant decomposes at 165 °C on titanium, which is the decomposition temperature of HAN, and 85 °C on platinum. Arrhenius-type reaction rate parameters were calculated from the results and used to develop thruster models. The [Emim] [EtSO4]-HAN propellant mixture is tested in a capillary electrospray emitter and exhibits stable electrospray emission at a nominal extraction voltage of 3400 V. The highest specific impulse attained in these experiments was 412 seconds; however, this could be improved with a more robust feed system design. This data, along with data from the monopropellant decomposition experiment is used to design a multi-mode micr
Small satellites are changing the space scene dramatically. By drastically reducing costs while still having impressive technological capabilities, their popularity among the space community is increasing at a very fast rate. Propulsion systems for these class of spacecraft are very limited. One promising technology is the ion Electrospray Propulsion System (iEPS) developed at the Space Propulsion Laboratory at MIT. Electrosprays accelerate ions present in the interface between an ionic liquid and vacuum using strong electric fields. Current thrust estimates for the iEPS modules land in the vicinity of tens of [mu]Newtons. Measuring the small thrust produced by the devices is challenging to say the least. This thesis presents the design and development of a Magnetically Levitated Thrust Balance (MLTB) for thrust estimation of the iEPS devices. The MLTB levitates an engineering model of a small satellite using magnetic fields inside a vacuum chamber. The zero friction environment is exploited to measure the minute thrust levels produced by the electrospray thrusters. Additional sensors and actuators that provide added functionality to the instrument are also explained. A fully stand-alone Power Processing Unit (PPU) capable of generating and delivering the high voltage signals needed to drive the thrusters is explained in detail. Test results of charging behavior and lifetime characterization of the emitted current are presented as a preliminary exploration of these processes.
Nanosatellites: Space and Ground Technologies, Operations and Economics Rogerio Atem de Carvalho, Instituto Federal Fluminense, Brazil Jaime Estela, Spectrum Aerospace Group, Germany and Peru Martin Langer, Technical University of Munich, Germany Covering the latest research on nanosatellites Nanosatellites: Space and Ground Technologies, Operations and Economics comprehensively presents the latest research on the fast-developing area of nanosatellites. Divided into three distinct sections, the book begins with a brief history of nanosatellites and introduces nanosatellites technologies and payloads, also explaining how these are deployed into space. The second section provides an overview of the ground segment and operations, and the third section focuses on the regulations, policies, economics, and future trends. Key features: Payloads for nanosatellites Nanosatellites components design Examines the cost of development of nanosatellites. Covers the latest policies and regulations. Considers future trends for nanosatellites. Nanosatellites: Space and Ground Technologies, Operations and Economics is a comprehensive reference for researchers and practitioners working with nanosatellites in the aerospace industry.
Franz Georg Hey summarises the development and testing of a micro-Newton thrust balance, as well as the downscaling of a High Efficiency Multistage Plasma Thruster to micro-Newton thrust levels. The balance is tailored to fully characterise thruster candidates for the space based gravitational wave detector LISA. Thus, thrust noise measurements in sub-micro-Newton regime can be performed in the overall LISA bandwidth. The downscaled thruster can be operated down to serval tens of micro-Newton with a comparably high specific impulse. About the Author Franz Georg Hey works as mechanical, thermal, propulsion architect and technical lead of the micro‐Newton propulsion laboratory of Europe’s leading air and spacecraft manufacturer. The author is participating on major programmes for future satellite and electric propulsion development. The author’s research is performed in close collaboration with the Dresden University of Technology, the University of Bremen and the DLR Bremen.
As the Czech ambassador to the United States, H. E. Petr Gandalovic noted in his foreword to this book that Mla Rechcgl has written a monumental work representing a culmination of his life achievement as a historian of Czech America. The Encyclopedia of Bohemian and Czech American Biography is a unique and unparalleled publication. The enormity of this undertaking is reflected in the fact that it covers a universe, starting a few decades after the discovery of the New World, through the escapades and significant contributions of Bohemian Jesuits and Moravian brethren in the seventeenth and eighteenth centuries, the mass migration of the Czechs after the revolutionary year of 1848, and up to the early years of the twentieth century and the influx of refugees from Nazism and communism. The encyclopedia has been planned as a representative, a comprehensive and authoritative reference tool, encompassing over 7,500 biographies. This prodigious and unparalleled encyclopedic vade mecum, reflecting enduring contributions of notable Americans with Czech roots, is not only an invaluable tool for all researchers and students of Czech American history but is also a carte blanche for the Czech Republic, which considers Czech Americans as their own and as a part of its magnificent cultural history.
No comprehensive study has been undertaken about the American learned men and women with Czechoslovak roots. The aim of this work is to correct this glaring deficiency, with the focus on men and women in medicine, applied sciences and engineering. It covers immigration from the period of mass migration and beyond, irrespective whether they were born in their European ancestral homes or whether they have descended from them. This compendium clearly demonstrates the Czech and Slovak immigrants, including Bohemian Jews, have brought to the New World, in these areas, their talents, their ingenuity, the technical skills, their scientific knowhow, as well as their humanistic and spiritual upbringing, reflecting upon the richness of their culture and traditions, developed throughout centuries in their ancestral home. This accounts for their remarkable success and achievements of theses settlers in the New World, transcending through their descendants, as this publication demonstrates. The monograph has been organized into sections by subject areas, i.e., Medicine, Allied Health Sciences and Social Services, Agricultural and Food Science, Earth and Environmental Sciences and Engineering. Each individual entry is usually accompanied with literature, and additional biographical sources for readers who wish to pursue a deeper study. The selection of individuals has been strictly based on geographical vantage, without regards to their native language or ethnical background. Some of the entries may surprise you, because their Czech or Slovak ancestry has not been generally known. What is conspicuous is a large percentage of listed individuals being Jewish, which is a reflection of high-level of education and intellect of Bohemian Jews. A prodigious number of accomplished women in this study is also astounding, considering that, in the 19th century, they rarely had careers and most professions refused entry to them.
Ionic Liquids (ILs) are now a world-wide phenomenon and have emerged from being viewed only as novel replacements for Volatile Organic Compounds (VOCs) traditionally used as industrial solvents, into designer materials with incredible untapped potential in a wide variety of fundamental scientific and technological areas. The current series of ACS symposia dedicated to ionic liquids and the resulting books are intended to change the way people think about ionic liquids and introduce the international audience to the many new possible applications for ionic liquids. The presentations and chapters will delve more deeply into the fundamental nature of ionic liquids responsible for their fascinating behavior.