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Ukrainian SPT-20 Hall effect thruster: analysis of the plume by optical emission spectroscopy

Pagnon B., Pellerin S., Dudeck M., Loyan A. V., Maksymenko T. A., Koshelev N. N.

Journal of Technical Physics

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2008

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Vol. 49, no 2

129-142

EN

The erosion of the ceramics made of Al2O3 of the SPT20 Hall effect thruster manufactured by the National Aerospace University "KhAI", has been studied by an optical method. The ratio of Al I, Xe I, Xe II emission lines was analysed using actinometry and coronal assumptions. The erosion rate of the ceramics has been evaluated for different operating conditions for the thrusters.

2

Spacecraft electric propulsion

Arrat D., Chesta E.

Journal of Technical Physics

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2008

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Vol. 49, no 3-4

169-176

EN

This paper presents an overview of the spacecraft electric propulsion activities at the French space agency (CNES). The main existing and future projects corresponding to low earth orbits and geostationary platforms are described. The field of application of electric propulsion is the station keeping of geostationary telecommunication satellites (@BUS), main propulsion for specific probes (SMART 1, new platform for scientific mission) and fine attitude control for dedicated micro-satellites (MICROSCOPE). The Research and Technology (R&T) program is also described in the paper. It covers various activities like research on plasma physics, equipment development and qualification and research on propulsion system. The R&T activities are dedicated to performance improvements of Hall effect thrusters, cathodes, the evaluation of the different low thrust technologies for formation flying applications. A constant effort is also put on plume effect.

3

Sizing of Hall effect thrusters with input power and thrust level: an empirical approach

Dannenmayer K., Mazouffre S.

Journal of Technical Physics

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2008

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Vol. 49, no 3-4

231-254

EN

Sizing methods can be used to get a first estimate of the required Hall thruster dimensions and operating conditions for a given input power and a corresponding thrust level. After a review of the existing methods, a new approach, which considers the three characteristic thruster dimensions, i.e. the channel length, the channel width and the channel mean diameter as well as the magnetic field, is introduced. This approach is based on analytical laws deduced from the physical principles that govern the properties of a Hall effect thruster, relying on a list of simplifying assumptions. In addition, constraints on the channel wall temperature as well as on the propellant atom density inside the channel are taken into account. The validity of the scaling laws is discussed in light of a vast database that comprises 23 single-stage Hall effect thrusters covering a power range from 10 W to 50 kW. Finally, the sizing method is employed to obtain a preliminary geometry and the magnetic field strength for a 20 kW and a 25 kW Hall effect thruster, able to deliver a thrust of 1 N, respectively 1.5 N.

4

PPS® 1350-G qualification status 10500 h

Marchandise F., Cornu N., Darnon F., Estublier D.

Journal of Technical Physics

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2008

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Vol. 49, no 3-4

303-313

EN

The PPS® 1350-G Hall Effect Thruster qualification process was continued to achieve 10500 h and 7300 cycles. This paper summarizes the obtained results and main observations for this rare end of life thruster. After a quick overlook of the 2002-2007 steps, it presents all along the lifetime the following parameters and their evolutions: thrust, flow rate, specific impulse, discharge current, discharge current oscillations, efficiency, erosion pattern, cathode parameters. The first end of life expertise will also be discussed. The success of this lifetime qualification at 3.3 10^6 Ns opens new spacecraft propulsion opportunities for high ΔV missions.

5

Performance investigation of SPT-20M low power Hall effect thruster

Loyan A. V., Maksymenko T. A.

Journal of Technical Physics

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2008

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Vol. 49, no 3-4

283-302

EN

The series of low power Hall effect thrusters (LPHT) SPT-20M was developed and manufactured in STC SPE of the National Aerospace University "KhAI". The main aim was to create a thruster with high performances: high specific impulse and the efficiency up to 40%. During SPT-20M experimental research a number of tests was made. The LPHT magnet system was investigated by taking into account construction thermal conditions. The experimental results show that final model SPT-20M6.1 has good enough performances with respect to the power consumption, which is lower than 100 W.

6

Monte Carlo simulations for HET ceramics sputtering yield prediction

Tondu T., Inguimbert V., Roussel J. F., D'escrivan S.

Journal of Technical Physics

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2008

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Vol. 49, no 3-4

363-373

EN

The Monte Carlo simulation code for ion sputtering CSiPI was developed for electric propulsion-induced erosion applications. In this paper we present how ceramics erosion can be treated. Indeed, these materials strongly differ from metals for which MC simulations are validated. We show that the target has to be resolved in time and space in order to deal with the target stoechiometry evolutions under ion bombardment. This is treated by the CSiPI2007 version of CSiPI. Then we propose a description for the characteristic binding energies that are opposed to some classical description. Indeed, we consider for ceramics a negligible surface binding energy compared to the bulk binding energy. This description is argued and a methodology is proposed for energies determination from the material atomization energy. This allows to perform the predictive sputtering yield Calculations. The code CSiPI and the proposed protocol for input data determination is validated by comparing simulations with experiments for BN, SiO2 and MgO. A good correlation is observed for normal ion bombardment by Xe+ ions in the 350-1000 eV range. For grazing incidence, experimental measurements depend strongly on the target roughness, then results are not directly comparable. At last, we present an estimation of erosion yields of the composite ceramics BN-SiO2 used in HETs.

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Investigation of hollow cathode for low power Hall effect thruster

Koshelev N. N., Loyan A. V.

Journal of Technical Physics

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2008

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Vol. 49, no 3-4

255-266

EN

In this paper we present the results of experimental studies of the gas-discharge hollow cathode (0.2-0.5 A) for low-power Hall thrusters (LPHET). Measurement campaign has been directed to construct a cathode with minimal power and gas consumption. Cathodes, which do not need the starting preheating system and for which the heating by glow discharge in working conditions is used, have the advantage of very simple construction and therefore will be objects of the reported research. It has been shown that the highest cathode performances were achieved: for Xe pressure inside cathode in the range 40 ÷ 60 torr and for emitter current density in the range 15 ÷ 25 A/cm². Direct firing tests of cathode emitters in the laboratory conditions, but close to real in the space, carried over more than 1000 hours are presented. It was found that the cathode power supply level did not exceed 5 W and the xenon mass flow rate supplying cathode was not greater than 0.05 mg/s.

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Generation and transport of laser-induced electron burst for a new diagnostic of Hall plasma thruster

Gilbert T., Leufroy A., Lazurenko A., Bouchoule A.

Journal of Technical Physics

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2008

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Vol. 49, no 2

143-161

EN

The Hall thrusters are developed in the field of spatial mission or satellite trajectories control. These thrusters are based on ejection of the ions from a E x B discharge. The physical understanding involves a lot of parameters. It is still today not fully controlled. Particularly, the electronic transport represents a challenge in the theoretical and experimental domains. This work presents the second part of an original diagnosis of electrons transport.

9

Current and plasma oscillation characterization in a PPS®-X000 Hall-effect thruster

Kurzyna J., Makowski K., Peradzyński Z., Lazurenko A., Mazouffre S., Coduti G., Dudeck M.

Journal of Technical Physics

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2008

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Vol. 49, no 3-4

267-282

EN

The correlations between local plasma oscillations and the discharge current or cathode potential variations are studied in a high-voltage Hall-effect thruster (HET). A set of electric probes is used to collect the signals. The probes are located in the exhaust region of the thruster, beyond its outer circumference. Measurements are performed for various probe positions and bias potentials, within a wide range of thruster operating conditions. The non-stationary signals are subsequently expanded into finite sets of intrinsic modes with the use of the Empirical Mode Decomposition (EMD) method. The Hilbert-Huang power spectra indicate characteristic bands in the low frequency (LF, tens of kHz), medium frequency (MF) and high frequency (HF, tens of MHz) range. However, the regular HF emission that has been observed in our previous low-voltage characterization of a PPS-100 thruster, is only observable in some particular operating conditions. When the supply voltage is low (e.g. 400 V), the known electrostatic drift wave propagating along the thruster azimuth is unambiguously identified in the probe signals. For higher voltages, HF spectra are usually broadband and do not highlight well the defined peaks. HF emission becomes very irregular or even seemingly random. On the other hand, when regular waves appear (intermittently or in series of bursts), frequencies in the ss 5-100 MHz band can be observed. The oscillations within the MF band that were previously weak in the PPS-100 thruster, appear now to dominate the discharge current spectrum when the thruster operates at the highest voltages. Intense oscillations in the MF range are identified with the use of positively biased probes and by examination of the cathode potential and discharge current variations. The correlations of all the mentioned signals are clear in this frequency band. Correlating the oscillations in the HF band with the MF discharge current wave, one can deduce that HF oscillations are periodically triggered by MF waves at high voltage, while at lower voltage they are triggered by the LF breathing mode, as previously observed in the case of the PPS-100 thruster.

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An empirical performance prediction model for Hall effect thrusters

Biagioni L., Saverdi M.

Journal of Technical Physics

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2008

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Vol. 49, no 3-4

187-200

EN

A statistical performance model for Hall effect thrusters is presented, which could be used both for predicting off-design performance of the existing thrusters or to obtain the preliminary characteristics (size, power level) of a new thruster with a specified performance. The statistical model is based on a large database of experimental data from the literature and Alta's own test and development activities. The predictive capabilities of the performance model are tested considering two recent Hall thrusters designed by Alta, the XHT-5 prototype operating at 5 kW and the HT-100 thrusters with a nominal operating power of 100 W.