ARTICLES

Performance comparison of LaB6 and C12A7:e- emitters for space electric propulsion cathodes

A. Post1, J. F. Plaza1, J. Toledo1, D. Zschätzsch2, M. Reitemeyer2, L. Chen2, A. Gurciullo3, A. Siegel4, P. J. Klar2, P. Lascombes3, and B. Seifert4.

1 Advanced Thermal Devices, C/Villaconejos 4, 28925-Alcorcon, Madrid, Spain

2 Institute of Experimental Physics I, Justus-Liebig-University, Hessen, 35392 Giessen, Germany

3 Exotrail, 3 Rue Galvani, 91300 Massy, France

4 FOTEC, Viktor Kaplan-Straße 2, 2700 Wiener Neustadt, Austria

 Abstract.

This work, based on an EU-funded project (NEMESIS), is summarising some of the results from the project activities on the research and development on electride-based cathode technology compatible with all kinds of electric propulsion (EP) systems requiring neutralization or electron emission. Further information describing in detail the performed tests and captured measurements can be found in the referenced documents of each section. Different cathode architectures and several emitter configurations with traditional and with alternative propellants are being developed and tested within the project, all of them using C12A7:e- electride material as thermionic electron source. Findings and conclusions derived from these multiple designs are allowing to figure out some of the key factors that determine the best performance of C12A7:eelectride based cathodes. In this work, a discussion of some of these key design and operation factors will be presented based both on the material characterization parameters, and on the performance tests carried out for the different cathode designs.

                Full article.

Journal: Material Science and Engineering. At 2022 IOP Conf. Ser.: Mater. Sci. Eng. 1226 012092

https://iopscience.iop.org/article/10.1088/1757-899X/1226/1/012092

Performance comparison of LaB6 and C12A7:e- emitters for space electric propulsion cathodes

J. Toledo1, J F Plaza1, A Post1, D Zschätzsch2, M Reitemeyer2, L Chen2, A. Gurciullo3, A Siegl4, P J Klar2, P. Lascombes3, and B. Seifert4.

1 Advanced Thermal Devices, C/Villaconejos 4, 28925-Alcorcon, Madrid, Spain

2 Institute of Experimental Physics I, Justus-Liebig-University, Hessen, 35392 Giessen, Germany

3 Exotrail, 3 Rue Galvani, 91300 Massy, France

4 FOTEC, Viktor Kaplan-Straße 2, 2700 Wiener Neustadt, Austria

 Abstract.

This work, based on an EU-funded project, NEMESIS, is aiming at developing electride-based cathode technology which is compatible with all kinds of electric propulsion systems requiring neutralization. Its target is to demonstrate and validate the performance of a novel C12A7:e- electride material as electron emitter instead of traditional thermionic emitters such as lanthanum hexaboride, LaB6, or barium oxide, BaO. In this study, a fair comparison between LaB6 and C12A7:e- samples was performed both addressing pure material characterization parameters as well as comparing performance as cathodes under different architectures and operational conditions. In this case, a current/cathode power ratio around 3 mA/W was obtained when using the C12A7:e- sample in a plasma environment with Ar, which is approximately one order of magnitude higher compared to the LaB6 sample.

                Full article.

Journal: Material Science and Engineering. At 2022 IOP Conf. Ser.: Mater. Sci. Eng. 1226 012093

https://iopscience.iop.org/article/10.1088/1757-899X/1226/1/012093

Ion thrusters for electric propulsion – scientific issues developing a niche technology into a game changer

K.Holste,1, a) P.Dietz,1 S.Scharmann,1 K.Keil,1 T.Henning,1 D.Zschätzsch,1 M.Reitemeyer,1 B.Nauschütt,1 F.Kiefer,1 F.Kunze,1 J.Zorn,1 C.Heiliger,2 N.Joshi,2 U.Probst,3 R.Thüringer,3 C.Volkmar,3 D.Packan,4 S.Peterschmitt,4 K.-T.Brinkmann,5 H.-G.Zaunick,5 M.H.Thoma,1 M.Kretschmer,1 H.J.Leiter,1 S.Schippers,1 K.Hannemann,1, 6 and P.J.Klar1

1) Institute of Experimental Physics I, Justus Liebig University, Heinrich-Buff-Ring 16, 35392 Giessen, Germany

2) Institute of Theoretical Physics, Justus Liebig University, Heinrich-Buff-Ring 16, 35392 Giessen, Germany

3) Department of Electrical Engineering, University of Applied Sciences, Wiesenstr. 14, 35390 Giessen, Germany

4) ONERA, Palaiseau 91120, France

5) Institute of Experimental Physics II, Justus Liebig University, Heinrich-Buff-Ring 16, 35392 Giessen, Germany

6) German Aerospace Center, Institute of Aerodynamics and Flow Technology, Spacecraft Department, Bunsenstrasse 10, 37073 Goettingen, Germany

Abstract:
The transition from OLD SPACE to NEW SPACE along with increasing commercialization has a major impact on space flight in general and on electric propulsion by ion thrusters in particular. Ion thrusters are nowadays used as primary propulsion systems in space. The article describes how these changes related to NEW SPACE affect various aspects that are important for the development of electric propulsion systems. Starting with a historical overview of the development of space flight and of the technology of electric propulsion systems, a number of important missions with EP and the underlying technologies are presented. The focus of our discussion is the technology of the radio frequency ion thruster as a prominent member of the gridded ion engine family. Based on this discussion, we give an overview of important research topics such as the search for alternative propellants, the development of reliable neutralizer concepts based on novel insert materials as well as promising neutralizer-free propulsion concepts. In addition, aspects of thruster modeling and requirements for test facilities are discussed. Furthermore, we address aspects of space electronics with regard to the development of highly efficient electronic components as well as aspects of electromagnetic compatibility and radiation hardness. The article concludes with a resentation of the interaction of electric propulsion systems with the spacecraft.