Development of a Micro ECR Ion Thruster for Space Propulsion

  • 沈 明學

Student thesis: Master's Thesis

Abstract

Ion thruster is a form of electric propulsion by generating thrust from ion acceleration Unlike chemical propulsions electric propulsion especially ion thruster has the strength of higher specific impulse (ISP) which means higher propulsion efficiency Accordingly it can meet the requirement of deep space exploration mission Ion thrusters have been used for many space missions such as Deep Space 1 in 1998 from NASA Artemis in 2001 from ESA Hayabusa 2 in 2014 from JAXA etc In the near future small lightweight low power satellites with correspondingly low power thrusters such as micro satellites or CubeSats will be implemented for deep space explorations We have designed a micro ion thruster with 80 mm in inner diameter and 94 mm in length for future CubeSat applications Electron Cyclotron Resonance (ECR) Plasma is generated under 875 G background magnetic fields supplied by solenoid The ions are initially accelerated from plasma generation region to the pre-acceleration region and further accelerated to high speed in main acceleration region Ions are accelerated by parallel electric fields supplied by metal grids In the thruster ion gyro-radius is 0 13 cm and its temperature is closed to room temperature To enhance thruster efficiency ion transparency should be much higher than neutral particle (fuel) transparency in the pre-acceleration region Ions should also be accelerated to higher initial speed before entering main acceleration region To investigate the combination effects of electric and magnetic fields on ion motion in this region single particle motion simulation is performed by SIMION software Ion lensing effect which reduces ion pitch angle effect and increases ion transparency can be raised by increasing thruster boundary potential Then the optimum pre-acceleration length can be determined to be the same as ion lensing focal length Furthermore the solenoid also provide a wall voltage to help increasing ion extraction efficiency Since we have few plasma inside the chamber cyclotron motion will initiate the chain reaction to enhance plasma density by collision effects between neutral particles and electrons Thus electron cyclotron resonance will do the job to accelerate electrons in order to make a high density ion source According to the simulation results of ion behaviors and ion optics the development of the micro ECR Ion thruster is undertaken Currently this is just a prototype system which the thrust is nearly 0 9 milli-newtons and specific impulse is around 1025~3076s with the calculation of diagnostics The thruster is tested by using Space Plasma Operation Chamber at National Cheng Kung University Tainan Taiwan
Date of Award2017 Feb 8
Original languageEnglish
SupervisorYei-Chin Chao (Supervisor)

Cite this

Development of a Micro ECR Ion Thruster for Space Propulsion
明學, 沈. (Author). 2017 Feb 8

Student thesis: Master's Thesis