Sub-Milli-Newton Class Miniature Microwave Ion Thruster

Nakayama, Yoshinori; Funaki, Ikkoh; Kuninaka, Hitoshi

doi:10.2514/1.21565

Cited by 21 publications

(10 citation statements)

References 8 publications

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“…Since a few years ago, several researchers have studied a micro ion engine using microwave discharge 8,9) . The simple structure of a microwave discharge ion engine is suitable for the miniaturization.…”

Section: Micro Ion Engines and Previous Workmentioning

confidence: 99%

Antenna Design Method and Performance Improvement of a Micro Ion Engine Using Microwave Discharge

Koizumi

Kuninaka

2009

Trans. JSASS Space Tech. Japan

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In this study, we are proposing a novel miniaturized ion engine system μ1. Recently microspacecraft and propulsion system to be installed there have attracted a lot of attentions. To accomplish the miniaturization of spacecraft component, multifunctionalization of devices are key technologies. The ion engine we are proposing here is distributed on microspacecraft and give a number of functions and strong redundancy to the spacecraft. To realize this concept, we introduced a novel idea for an ion engine system. That is to use single plasma source as both ion beam source and neutralizing electron source only by electrical connection. This ion engine system is released from the necessity of a number of neutralizers. Our concept requires a plasma source driven by very low power microwave. Here we proposed an antenna design method for a small plasma source using microwave discharge, and developed a miniaturized ion engine. As a result, the performance of the miniaturized ion engine was improved up to the ion production cost of 240 V and propellant utilization efficiency of 40 % at the input microwave power of 1.0 W and mass flow rate of 0.15 sccm.

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Section: Micro Ion Engines and Previous Workmentioning

confidence: 99%

Antenna Design Method and Performance Improvement of a Micro Ion Engine Using Microwave Discharge

Koizumi

Kuninaka

2009

Trans. JSASS Space Tech. Japan

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“…The action of the ions leaving the thruster causes a reaction that pushes the spacecraft in the opposite direction. [9][10][11][12][13][14] Wirz et al showed good performance of a 30 mm miniature xenon ion ͑MiXI͒ thruster, that is, the propellant utilization and the ion beam production cost were 0.8 and 500 W/A, respectively, for a mass flow rate of 0.02 mg/s. A pair of grids in the ion thruster accelerates the ions to very high speed, such as 30 000-80 000 m/s, and shoots them out of the thruster.…”

Section: Introductionmentioning

confidence: 99%

Effects of magnetic field configuration on thrust performance in a miniature microwave discharge ion thruster

Yamamoto

Kondo

Chikaoka

et al. 2007

Journal of Applied Physics

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Articles you may be interested inIon ejection from a permanent-magnet mini-helicon thruster Phys. Plasmas 21, 093511 (2014); 10.1063/1.4896238 Measurement of axial neutral density profiles in a microwave discharge ion thruster by laser absorption spectroscopy with optical fiber probes Rev. Sci. Instrum. 82, 123103 (2011); 10.1063/1.3665954 Effect of applied magnetic field on a microwave plasma thruster Phys. Plasmas 15, 023503 (2008); 10.1063/1.2841026 Effect of magnetic field profile on the anode fall in a Hall-effect thruster dischargea) Phys. Plasmas 13, 057104 (2006); 10.1063/1.2174825The ultimate performance of gridded ion thrusters for interstellar missions AIP Conf.The effects of magnetic field configuration on thrust performance in a miniature microwave discharge ion thruster were investigated in order to improve thrust performance. First, the extracted ion beam current was measured for various levels of strength of the magnetic field. It was found that there is an optimum magnitude of the magnetic field. That this is due to the tradeoff between magnetic mirror confinement and microwave-plasma coupling was confirmed by measurement of the ion saturation current into the antenna of the ion thruster. The ion saturation current was found to decrease with an increase in magnetic field strength, due to the improvement in magnetic mirror confinement. The estimated electron temperature also decreases with an increase in magnetic field strength. This result shows that the increase in magnetic field strength leads to a decrease in microwave-plasma coupling. Next, the ion beam current for three magnetic field shapes was measured by changing the length of the central yoke. The results show that the optimum magnetic field shape depends on the mass flow rate because of the tradeoff between magnetic confinement and ionization probability. For the configurations tested, the 3 mm length central yoke is optimal for low mass flow, whereas 7 mm is the best for high mass flow. Overall, the extracted ion beam current is 21.4 mA, at a xenon mass flow rate of 0.036 mg/s, beam voltage of 1500 V, and incident microwave power of 16 W.

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“…To date, several studies on miniature ion thrusters have been conducted for several different types of the plasma generators, namely direct current electron discharges, 11,12) radio frequency discharges, 13) and microwave discharges. [14][15][16][17] In spite of these benefits, however, miniature ion thrusters have not been employed on small spacecraft yet. This is mainly caused by two significant reasons.…”

Section: Introductionmentioning

confidence: 99%

Switching Operation of Ion Beam Extraction and Electron Emission Using the Miniature Ion Thruster μ1

Koizumi

Kuninaka

2010

AEROSPACE TECHNOLOGY JAPAN

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Ion thrusters are promising propulsion devices not only for standard-sized spacecraft but also for small spacecraft. However, difficulty of the development of a miniature neutralizer has been a critical problem for miniature ion thrusters. We have proposed a novel ion thruster system to solve this problem. That is a switching operation, where a plasma source can select ion beam extraction or electron emission by electrical switching. The major challenge of this study is to find the method to effectively performs both functions from one plasma source. To match the system to small spacecraft, the both modes must be conducted using low microwave power and low mass flow as low as 1.0 W and 0.15 sccm. Firstly, fundamental characteristics of electron emission were investigated using an orifice plate. Based on this result, secondly, a special grid system for the switching operation was designed and examined. This grid system has two-different-size apertures for ions and electrons respectively. This grid showed high ion beam extraction performance, that is, 4.1 mA ion beam current at 1.0 W microwave power input. It also showed much higher electron current than the old grid system, although the electron current of 1.0 mA has not reached the targeted current yet. As a result, the experiment showed that the special grid system proposed here is an effective method to realize the switching operation.

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Sub-Milli-Newton Class Miniature Microwave Ion Thruster

Cited by 21 publications

References 8 publications

Antenna Design Method and Performance Improvement of a Micro Ion Engine Using Microwave Discharge

Antenna Design Method and Performance Improvement of a Micro Ion Engine Using Microwave Discharge

Effects of magnetic field configuration on thrust performance in a miniature microwave discharge ion thruster

Switching Operation of Ion Beam Extraction and Electron Emission Using the Miniature Ion Thruster μ1

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