Note from the Series Editor. Foreword. Preface. Acknowledgments. Chapter 1: Introduction. 1.1 Electric Propulsion Background. 1.2 Electric Thruster Types. 1.3 Ion Thruster Geometry. 1.4 Hall Thruster Geometry. 1.5 Beam/Plume Characteristics. References. Chapter 2: Thruster Principles. 2.1 The Rocket Equation. 2.2 Force Transfer in Ion and Hall Thrusters. 2.3 Thrust. 2.4 Specific Impulse. 2.5 Thruster Efficiency. 2.6 Power Dissipation. 2.7 Neutral Densities and Ingestion in Electric Thrusters. References. Problems. Chapter 3: Basic Plasma Physics. 3.1 Introduction. 3.2 Maxwell's Equations. 3.3 Single Particle Motions. 3.4 particle Energies and Velocities. 3.5 Plasma as a Fluid. 3.6 Diffusion in Partially Ionized Gases. 3.7 Sheaths at the Boundaries of Plasmas. References. Problems. Chapter 4: Ion Thruster Plasma Generators. 4.1 Introduction. 4.2 Idealized Ion Thruster Plasma Generator. 4.3 DC Discharge Ion Thruster. 4.4 Kaufman Ion Thrusters. 4.5 rf Ion Thrusters. 4.6 Microwave Ion Thrusters. 4.7 2-D Computer Models of the Ion Thruster Discharge Chamber. References. Problems. Chapter 5: Ion Thruster Accelerator Grids. 5.1 Grid Configurations. 5.2 Ion Accelerator Basics. 5.3 Ion Optics. 5.4 Electron Backstreaming. 5.5 High-Voltage Considerations. 5.6 Ion Accelerator Grid Life. References. Problems. Chapter 6: Hollow Cathodes. 6.1 Introduction. 6.2 Cathode Configurations. 6.3 Thermionic Electron Emitter Characteristics. 6.4 Insert Region Plasma. 6.5 Orifice Region Plasma. 6.6 Hollow cathode Thermal Models. 6.7 Cathode Plume-Region Plasma. 6.8 Hollow Cathode Life. 6.9 Keeper Wear and Life. 6.10 Hollow Cathode Operation. References. Problems. Chapter 7: Hall Thrusters. 7.1 Introduction. 7.2 Thruster Operating Principles and Scaling. 7.3 Hall Thruster Performance Models. 7.4 Channel Physics and Numerical Modeling. 7.5 Hall Thruster Life. References. Problems. Chapter 8: Ion and Hall Thruster Plumes. 8.1 Introduction. 8.2 Plume Physics. 8.3 Plume Models. 8.4 Spacecraft Interactions. 8.5 Interactions with Payloads. References. Problems. Chapter 9: Flight Ion and Hall Thrusters. 9.1 Introduction. 9.2 Ion Thrusters. 9.3 Hall Thrusters. References. Appendices. A: Nomenclature. B: Gas Flow Unit Conversions and Cathode Pressure Estimates. C: Energy Loss by Electrons. D: Ionization and Excitation Cross Sections for Xenon. E: Ionization and Excitation Reaction Rates for Xenon in Maxwellian Plasmas. F: Electron Relaxation and Thermalization Times. G: Clausing Factor Monte Carlo Calculation. Index..

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Fundamentals of electric propulsion : ion and Hall thrusters

This contribution presents a short review of electric propulsion (EP) technologies for satellites and spacecraft. Electric thrusters, also termed ion or plasma thrusters, deliver a low thrust level compared to their chemical counterparts, but they offer significant advantages for in-space propulsion as energy is uncoupled to the propellant, therefore allowing for large energy densities. Although the development of EP goes back to the 1960s, the technology potential has just begun to be fully exploited because of the increase in the available power aboard spacecraft, as demonstrated by the very recent appearance of all-electric communication satellites. This article first describes the fundamentals of EP: momentum conservation and the ideal rocket equation, specific impulse and thrust, figures of merit and a comparison with chemical propulsion. Subsequently, the influence of the power source type and characteristics on the mission profile is discussed. Plasma thrusters are classically grouped into three categories according to the thrust generation process: electrothermal, electrostatic and electromagnetic devices. The three groups, along with the associated plasma discharge and energy transfer mechanisms, are presented via a discussion of long-standing technologies like arcjet thrusters, magnetoplasmadynamic thrusters, pulsed plasma thrusters and ion engines, as well as Hall thrusters and variants. More advanced concepts and new approaches for performance improvement are discussed afterwards: magnetic shielding and wall-less configurations, negative ion thrusters and plasma acceleration with a magnetic nozzle. Finally, various alternative propellant options are analyzed and possible research paths for the near future are examined.

http://iopscience.iop.org/article/10.1088/0963-0252/25/3/033002/pdf

Electric propulsion for satellites and spacecraft: established technologies and novel approaches

Potential and prospective implementation of carbon nanotubes on next generation aircraft and space vehicles: A review of current and expected applications in aerospace sciences

The technological and commercial expansion of electric propulsion

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The Influence of Neutral Flow Rate in the Operation of Hall Thrusters.

The SMART-1 Electric Propulsion Subsystem around the Moon: In Flight Experience

Onboard the ESA SMART-1 spacecraft, (Small Mission for Advanced Research in Technology), the primary Electric Propulsion Subsystem (EPS) operates since the 30 th September 2003, allowed the capture by the Moon on the 15 th of November 2004 and finally the propulsion pushes the spacecraft to the operational orbit around the Moon on 27 th February 2005. The total in-flight accumulated hours of the thruster is about 5000 hours. And more than 800 times, the EPS was started. The first comment gained from the in-flight experience is that the EPS availability to perform the thrust function is recorded as 100%. One shall in addition point out that this performance was obtained even during the successive crossing of the Van Allen radiation belts. The particular orbit followed by SMART-1 to reach the Moon, to be captured and to reaches the operational Moon orbit, has fully confirmed the suitability of the Hall effect thruster to perform such high sensitive orbit maneuvers near the capture. EPS Contractor, ESTEC, and EPS manufacturer, SNECMA MOTEURS, will present in detail the major's performances of the complete electric propulsion system, with respect to the long life duration achieved. The main feature of the SMART-1 system is its variable power supply. The PPS ® -1350-G Hall Effect plasma Thruster and its Power processing unit, were developed in the frame of the CNES Stentor Program. Results of the in flight EPS includes the behavior of the robust bang-bang xenon pressure regulation for the input pressure and variable electrical power supply. This paper describes the performance results of the PPS ® -1350-G firing in space environment. It discusses also the particular behavior of the floating potential of the thruster with respect to the satellite orbital position and its sun incidence along years. The successful results obtained support the first technological experience objective of the SMART-1 mission. The performance in term of thrust or total impulse is discussed as well as the main lessons learned. These new features of primary electric propulsion subsystem and especially the low-power start-up and variable power features can be also a significant added value for any commercial application using electric propulsion for station-keeping and/or orbit transfer. The mission of the EPS, completed now, ended after performing a one and half month maneuver dealing with the increase of the orbital life by one more year.

The SMART-1 Hall Effect Thruster Around the Moon: In Flight Experience

Onboard the ESA SMART-1 spacecraft, (Small Mission for Advanced Research and Technology), the primary Electric Propulsion Subsystem (EPS) must operate at optimum performance under limited power available and with a variable power feature. As EPS Contractor for ESA-ESTEC, SNECMA present in detail the major's features of the complete electric propulsion system, as well as the development efforts of each main component. The development tests of the PPS-1350-G hall effect plasma thruster, including an extensive number of start-up tests in the whole useful operational domain have been performed. This paper describes the results of the PPS-1350 low-power characterization tests, and presents the new approach for having a limited inrush power when the thruster is switched on. The test campaign has been successful and the results obtained during the campaign have been fully taken into account in an optimization process for providing the foreseen performances of the SMART-1 mission. Those performances are the thrust, the total xenon flow, the specific impulse and the additional magnet trim current. Acceptance tests of each components of the EPS have been performed and finally an "end to end" test has been successfully performed at satellite level. These new features of primary electric propulsion subsystem and especially the low-power start-up and variable power features can be also a significant added value for any commercial application using electric propulsion for station-keeping and/or orbit transfer. Introduction Although High Specific Impulse Thrusters have already propelled numerous satellites in the frame of station-keeping missions, their use for orbit transfer and deep space missions has only recently begun, bringing out a need for new thrust strategies. The Snecma PPS1350-G Hall-effect thruster is primarily intended for North South station keeping of Geo-stationary satellites. For that kind of application, the spacecraft available power is much higher than the PPU maximum power demand, so there is no risk to overload the spacecraft power bus. In the case of SMART-1 , on the contrary, the PPU power could exceed the total spacecraft power. In addition, the thruster shall be able to work with less than half its nominal power. To fulfil these requirements, it was necessary to modify the thruster/PPU interfaces and to validate these modifications by tests. SMART-1 Electric Propulsion Subsystem (EPS) The SMART-1 power is generated by two solar panels enabling thruster operation at a discharge power of maximum 1190 W at beginning of life . In some cases, (e.g. failure of one solar wing in addition to solar cells) the available power can be reduced to 700 W or less. This is therefore an essential requirement for thruster and PPU to work within a range of pre-set power levels. This capability is also required for deep-space missions involving variable sun distances. The whole EPS is designed for the three following main functions : u Xenon system u Electrical power system and thruster u Digital interface and communication system 39th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit 20-23 July 2003, Huntsville, Alabama AIAA 2003-4545 Copyright © 2003 by Snecma Moteurs and ESA. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission. 2 PPU/TSU Bus Input, Input Switch

The Smart-1 Electric Propulsion Subsystem

Results of these main tests demonstrate a good prediction of the in flight EPS behavior including the robust bang-bang xenon pressure regulation for the input pressure and variable electrical power supply. This paper describes the performance results of the PPS-1350-G firing in space environment. It discusses also the consequences of the Van Allen radiation belt crossing during the first flight phase, particularly the behavior of the floating potential of the thruster with respect to the satellite electrical ground.

The SMART-1 Electric Propulsion Subsystem In Flight Experience

A first satellite is placed practically directly by a launcher on a first final orbit. A second satellite is placed on the same launcher is initially transferred to a highly elliptical waiting orbit whose semi-major axis points to intercept the torus formed by the sphere of influence of the moon on its orbit, and then during a maneuver at the perigee of the highly elliptical orbit, the second satellite is transferred to lunar transfer orbit. Changes in the perigee altitude and the inclination of an intermediate orbit on which the second satellite is to be found are obtained mainly by gravitational reaction in the sphere of influence of the moon, and during a last maneuver, the second satellite is placed on a final orbit having orbital parameter values that are quite different from those of the orbital parameters of the first final orbit.

Christophe Koppel

Papers

The SMART-1 Electric Propulsion Subsystem around the Moon: In Flight Experience

The SMART-1 Hall Effect Thruster Around the Moon: In Flight Experience

The Smart-1 Electric Propulsion Subsystem

The SMART-1 Electric Propulsion Subsystem In Flight Experience

Method and a system for launching satellites on non-coplanar orbits, making the use of gravitational assistance from the moon