The 35-year history of the development and application of the pulsed plasma thruster (PPT) is reviewed. The PPT operates by creating a pulsed, high-current discharge across the exposed surface of a solid insulator, such as a Tee on t bar. The arc discharge ablates material from this surface, thereby providing propellant that is ionized, heated, and accelerated to high speed. Typically, the current pulse lasts for a few microseconds, driven by a capacitor that is charged and discharged approximately once per second. Exhaust speeds range from 3 to 50 km/s, depending on the details of the PPT design. We review the basic physics and types of PPTs, and discuss the performance of e ight and laboratory versions, with special attention to velocity and plume measurements. We also present the status of PPT theory and modeling, with emphasis on mass evolution and plasma acceleration, and describe recent variations on PPT operation, laboratory thrust measurement techniques, and the separate components of PPT efe ciency.

Pulsed Plasma Thruster

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

This review presents the basics of plasma discharges applied to electric spacecraft propulsion. It briefly reports on the mature and flown technologies of gridded ion thrusters and Hall thrusters before exploring the recent yet immature technology of plasma thrusters based on expansion from low pressure high density inductively coupled and wave-excited plasma sources, e.g. the radiofrequency helicon source. Prototype development of plasma engines for future space travel is discussed using the example of the helicon double layer thruster. A summary of highlights in electric propulsion based space missions gives some insight into the challenges of future high power missions in more remote regions of space.

/pdf/plasmas-for-spacecraft-propulsion-4uknp98tfc.pdf

Plasmas for spacecraft propulsion

∗Chair of AIAA’s Electric Propulsion Technical Committee, 2002-2004. Associate Fellow AIAA. Chief Scientist at Princeton University’s Electric Propulsion and Plasma Dynamics Laboratory (EPPDyL). Associate Professor, Applied Physics Group, MAE Department. e-mail: choueiri@princeton.edu. †Presented at the 40th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, Ft. Lauderdale, FL. Copyright c © 2004 by the author. Published by the AIAA with permission. Also published in the Journal of Propulsion and Power, Vol. 20, No. 2, pp. 193–203, MarchApril 2004. When writing history, it is tempting to identify thematic periods in the often continuous stream of events under review and label them as “eras”, or to point to certain achievements and call them “milestones”. Keeping in mind that such demarcations and designations inevitably entail some arbitrariness, we shall not resist this temptation. Indeed, the history of electric propulsion (EP), which now spans almost a full century, particularly lends itself to a subdivision that epitomizes the progress of the field from its start as the dream realm of a few visionaries, to its transformation into the concern of large corporations. We shall therefore idealize the continuous history of the field as a series of five essentially consecutive eras:

https://alfven.princeton.edu/papers/choueiriJPP04a.pdf

A Critical History of Electric Propulsion: The First 50 Years (1906-1956)

This dissertation presents research aimed at extending the efficient operation of 1600 s specific impulse Hall thruster technology to the 2000 to 3000 s range. Motivated by previous industry efforts and mission studies, the aim of this research was to develop and characterize xenon Hall thrusters capable of both high-specific impulse and high-efficiency operation. During the development phase, the laboratory-model NASA 173M Hall thrusters were designed and their performance and plasma characteristics were evaluated. Experiments with the NASA-173M version 1 (v1) validated the plasma lens magnetic field design. Experiments with the NASA 173M version 2 (v2) showed there was a minimum current density and optimum magnetic field topography at which efficiency monotonically increased with voltage. Comparison of the thrusters showed that efficiency can be optimized for specific impulse by varying the plasma lens. During the characterization phase, additional plasma properties of the NASA 173Mv2 were measured and a performance model was derived. Results from the model and experimental data showed how efficient operation at high-specific impulse was enabled through regulation of the electron current with the magnetic field. The electron Hall parameter was approximately constant with voltage, which confirmed efficient operation can be realized only over a limited range of Hall parameters.

/pdf/development-and-characterization-of-high-efficiency-high-50q4vw4pje.pdf

Development and Characterization of High-Efficiency, High-Specific Impulse Xenon Hall Thrusters

Book on physics of electric propulsion covering gas acceleration principles, flow heating and space thrustor design

F. A. Lyman

Papers

Physics of Electric Propulsion