Recent progress in research and development of hollow cathodes for electric propulsion

Lev, Dan; Mikellides, Ioannis G.; Pedrini, Daniela; Goebel, Dan M.; Jorns, Benjamin; McDonald, Michael

doi:10.1007/s41614-019-0026-0

Cited by 90 publications

(60 citation statements)

References 187 publications

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“…Varying the strong magnetic field around the cathode, which is used for ignition and discharge of the plasma, could also help to reduce erosion and improve lifetime [66]. Hollow cathodes, as shown in (c) of Figure 2, however, typically have a long life and offer robust performance [59,67]. For small satellites with low power, a heaterless hollow cathode is a popular choice as it reduces weight, has a compact size and is suitable under low power conditions [68].…”

Section: Hall Thrustermentioning

confidence: 99%

Electric Propulsion Methods for Small Satellites: A Review

2021

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Over 2500 active satellites are in orbit as of October 2020, with an increase of ~1000 smallsats in the past two years. Since 2012, over 1700 smallsats have been launched into orbit. It is projected that by 2025, there will be 1000 smallsats launched per year. Currently, these satellites do not have sufficient delta v capabilities for missions beyond Earth orbit. They are confined to their pre-selected orbit and in most cases, they cannot avoid collisions. Propulsion systems on smallsats provide orbital manoeuvring, station keeping, collision avoidance and safer de-orbit strategies. In return, this enables longer duration, higher functionality missions beyond Earth orbit. This article has reviewed electrostatic, electrothermal and electromagnetic propulsion methods based on state of the art research and the current knowledge base. Performance metrics by which these space propulsion systems can be evaluated are presented. The article outlines some of the existing limitations and shortcomings of current electric propulsion thruster systems and technologies. Moreover, the discussion contributes to the discourse by identifying potential research avenues to improve and advance electric propulsion systems for smallsats. The article has placed emphasis on space propulsion systems that are electric and enable interplanetary missions, while alternative approaches to propulsion have also received attention in the text, including light sails and nuclear electric propulsion amongst others.

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Section: Hall Thrustermentioning

confidence: 99%

Electric Propulsion Methods for Small Satellites: A Review

2021

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“…As high temperatures are needed for thermionic emission, materials that can withstand very high temperatures are used in hollow cathodes. Thermal design of the hollow cathodes is crucial for its operational characteristics and lifetime, as heat losses determine the required power level of the heater element for the initiation of the cathode operation as well as sustaining the operation [21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Thermal Analysis and Testing of Different Designs of LaB6 Hollow Cathodes to Be Used in Electric Propulsion Applications

2021

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LaB6 emitters are commonly used in hollow cathodes that are utilized in electric space propulsion systems. In order to obtain necessary surface current emission densities of 1–10 A/cm2 for cathode operations, LaB6 emitters require temperatures above 1500 °C. Hence, the design for LaB6 cathodes presents thermal and mechanical challenges. In this paper, several design iterations for LaB6 hollow cathodes are presented and thermal analyses are conducted for each design. Temperature and heat flux distributions that are obtained from thermal analyses are investigated. The designs are evaluated according to the required heat input to the emitter, and the radiative and conductive heat loss mechanisms. In addition to the thermal analyses, experimental tests are conducted for different cathode designs and, based on these tests, various modes of failure are determined. Revising the cathode design and the material selection iteratively to eliminate the encountered failure mechanisms, a novel cathode design is achieved. Experimental tests of this novel cathode are conducted and current-voltage characteristics are presented for different mass flow rates and for discharge currents between 0.5 and 12 A. Tests and analysis results show that the selection of materials and design are crucial for a sturdy and long lifetime cathode.

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“…Thermionic hollow cathodes are a critical component for electrostatic propulsion devices as the electron current they emit is required for neutralization of the ion beam generated by the thruster [1]. Moreover, in the case of Hall thrusters, electrons generated by the cathode also play a key role in ion production and plasma discharge sustainment [7,8]. The hollow cathode technology has greatly evolved and improved over the past decades thanks to advances in material science, manufacture processes and numerical simulations as explained in several articles [8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, in the case of Hall thrusters, electrons generated by the cathode also play a key role in ion production and plasma discharge sustainment [7,8]. The hollow cathode technology has greatly evolved and improved over the past decades thanks to advances in material science, manufacture processes and numerical simulations as explained in several articles [8][9][10][11][12]. Available cathodes are stable and efficient, have a long lifespan and are able to operate in a wide range of discharge currents from less than 1 A up to several tens of Amperes.…”

Section: Introductionmentioning

confidence: 99%

Discharge and plasma plume characterization of a 100 A-class LaB6 hollow cathode

Mazouffre

Joussot

Vincent

et al. 2021

Journal of Applied Physics

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HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

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Recent progress in research and development of hollow cathodes for electric propulsion

Cited by 90 publications

References 187 publications

Electric Propulsion Methods for Small Satellites: A Review

Electric Propulsion Methods for Small Satellites: A Review

Thermal Analysis and Testing of Different Designs of LaB6 Hollow Cathodes to Be Used in Electric Propulsion Applications

Discharge and plasma plume characterization of a 100 A-class LaB6 hollow cathode

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