Experimental demonstration of a water electrolysis Hall Effect Thruster (WET-HET) operating with a hydrogen cathode
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Published version
Author(s)
Munoz Tejeda, Jesus Manuel
Potrivitu, George
Rosati Azevedo, Emmanuelle
Moloney, Rachel
Knoll, Aaron
Type
Journal Article
Abstract
This study presents the first experimental demonstration of a Hall Effect Thruster operating with water
electrolysis-derived constituents: oxygen for the anode (thruster) and hydrogen for the cathode, both from
pressurised bottles. In contrast to prior research where the thruster was operated with oxygen to the anode
and xenon/krypton to the cathode, this investigation uses an advanced set-up that safely allowed the combined use of pressurised oxygen and hydrogen. Firstly, a comparative assessment between the established plasma filament cathode (utilised in previous research) and a novel 𝐿𝑎𝐵6 cathode (referred to as Hydrocat ), both krypton-fuelled, is conducted. Results show a different IV curve for these cathodes, but negligible disparities in thruster performance for fixed discharge power and anode mass flow. Thrust, anode specific impulse, thrust-to-power ratio, and both, anode and total efficiency of the system using oxygen (anode) and hydrogen (cathode) are then presented and compared against oxygen (anode) and krypton (cathode). The cathode successfully operated on hydrogen, with a reduction in thrust performance of under 10% compared to when krypton is used as the cathode propellant. This performance difference can be attributed to different factors, such as the reduced efficiency of the cathode running with hydrogen due to a higher ionisation potential and the cathode propellant’s contribution to thrust, more significant when using heavier propellants such as xenon/krypton compared to hydrogen. The impact of changing the hydrogen-to-oxygen ratio is also assessed and shown to have no impact on the thruster’s performance. The most optimal performance was obtained at the highest discharge power tested (𝑃𝑑 = 1953 ± 1 W), using a hydrogen:oxygen ratio of 𝛷 = 1:25. This operating point corresponded to a thrust of 20.9±0.2 mN, anode specific impulse of 2130±20 s, thrust-to-power ratio of 10.7±0.5 mN/kW, anode thrust efficiency of 11.2 ± 0.3 %, and total efficiency of 10.1 ± 0.3 %.
electrolysis-derived constituents: oxygen for the anode (thruster) and hydrogen for the cathode, both from
pressurised bottles. In contrast to prior research where the thruster was operated with oxygen to the anode
and xenon/krypton to the cathode, this investigation uses an advanced set-up that safely allowed the combined use of pressurised oxygen and hydrogen. Firstly, a comparative assessment between the established plasma filament cathode (utilised in previous research) and a novel 𝐿𝑎𝐵6 cathode (referred to as Hydrocat ), both krypton-fuelled, is conducted. Results show a different IV curve for these cathodes, but negligible disparities in thruster performance for fixed discharge power and anode mass flow. Thrust, anode specific impulse, thrust-to-power ratio, and both, anode and total efficiency of the system using oxygen (anode) and hydrogen (cathode) are then presented and compared against oxygen (anode) and krypton (cathode). The cathode successfully operated on hydrogen, with a reduction in thrust performance of under 10% compared to when krypton is used as the cathode propellant. This performance difference can be attributed to different factors, such as the reduced efficiency of the cathode running with hydrogen due to a higher ionisation potential and the cathode propellant’s contribution to thrust, more significant when using heavier propellants such as xenon/krypton compared to hydrogen. The impact of changing the hydrogen-to-oxygen ratio is also assessed and shown to have no impact on the thruster’s performance. The most optimal performance was obtained at the highest discharge power tested (𝑃𝑑 = 1953 ± 1 W), using a hydrogen:oxygen ratio of 𝛷 = 1:25. This operating point corresponded to a thrust of 20.9±0.2 mN, anode specific impulse of 2130±20 s, thrust-to-power ratio of 10.7±0.5 mN/kW, anode thrust efficiency of 11.2 ± 0.3 %, and total efficiency of 10.1 ± 0.3 %.
Date Issued
2024-06-01
Date Acceptance
2024-03-21
Citation
Acta Astronautica, 2024, 219, pp.542-554
ISSN
0094-5765
Publisher
Elsevier
Start Page
542
End Page
554
Journal / Book Title
Acta Astronautica
Volume
219
Copyright Statement
© 2024 The Author(s). Published by Elsevier Ltd on behalf of IAA. This is an open access article under the CC BY license
(http://creativecommons.org/licenses/by/4.0/).
(http://creativecommons.org/licenses/by/4.0/).
License URL
Publication Status
Published
Date Publish Online
2024-03-26