UC Irvine UC Irvine Electronic Theses and Dissertations Title Electrospray Thrusters for Attitude Control of a 1-U CubeSat Permalink https://escholarship.org/uc/item/3506d0z7 Author Timilsina, Navin Publication Date 2014 License https://creativecommons.org/licenses/by/4.0/ 4.0 Peer reviewed|Thesis/dissertation eScholarship.org Powered by the California Digital Library University of California UNIVERSITY OF CALIFORNIA, IRVINE Electrospray Thrusters for Attitude Control of a 1-U CubeSat THESIS submitted in partial satisfaction of the requirements for the degree of MASTER OF SCIENCE in Mechanical and Aerospace Engineering by Navin Timilsina Thesis Committee: Associate Professor Manuel Gamero-Castano, Chair Professor Roger H. Rangel Associate Professor Lorenzo Valdevit 2014 © 2014 Navin Timilsina TABLE OF CONTENTS Page LIST OF TABLES ....................................................................................................................... vi LIST OF FIGURES .................................................................................................................... ix ACKNOWLEDGEMENTS ........................................................................................................ xvi ABSTRACT OF THE THESIS ................................................................................................. xvii 1. INTRODUCTION ................................................................................................................ 1 1.1 Electrospray Technique ............................................................................................... 1 1.2 CubeSat ....................................................................................................................... 3 1.3 Objectives of the Thesis ............................................................................................... 4 2. CONDUCTIVITY MEASUREMENT OF PROPELLANTS .................................................... 5 2.1 Introduction .................................................................................................................. 5 2.2 Theory ......................................................................................................................... 5 2.3 Experimental Setup ...................................................................................................... 6 2.4 Results ......................................................................................................................... 7 3. TIME-OF-FLIGHT TECHNIQUE ......................................................................................... 9 3.1 Introduction .................................................................................................................. 9 3.2 Experimental Hardware ..............................................................................................11 3.3 Steps to initiate and end properly an experiment ........................................................14 3.3.1 Steps to Initiate ....................................................................................................17 3.3.2 Steps to Close .....................................................................................................18 3.4 Experimental Procedure..............................................................................................19 ii 3.4.1 Liquids analyzed and measurements done ..........................................................19 3.4.2 Correction of data obtained ..................................................................................20 3.5 Programming Code .....................................................................................................22 3.5.1 Function ‘reading_filename’ .................................................................................22 3.5.2 Function ‘arrange_data’ .......................................................................................23 3.5.3 Main Code ...........................................................................................................23 3.6 Results ........................................................................................................................24 3.6.1 Colloid Beam Phenomenology .............................................................................24 3.6.2 Measurement of Thrust and Specific Impulse ......................................................43 3.6.3 Comparison of several propellants .......................................................................68 4. ACS TEST IN CUBESAT ...................................................................................................73 4.1 Theory ........................................................................................................................73 4.1.1 Electrospray Formation ........................................................................................73 4.1.2 Capillary Action ....................................................................................................78 4.1.3 Thruster configuration ..........................................................................................79 4.1.4 Measurement of Current in the Circuit..................................................................79 4.1.5 Wire .....................................................................................................................81 4.1.6 Electronic Circuit ..................................................................................................85 4.2 Design ........................................................................................................................86 4.2.1 Machines Used ....................................................................................................86 4.2.2 Satellite Parts.......................................................................................................87 iii 4.2.3 Electronic Circuit ..................................................................................................95 4.2.4 Wireless Communication .....................................................................................96 4.2.5 Assembly .............................................................................................................99 4.3 Tests .........................................................................................................................103 4.3.1 Battery-Vacuum Compatibility ............................................................................103 4.3.2 Wireless Signal Transfer ....................................................................................105 4.3.3 Passive Feeding ................................................................................................105 4.3.4 ACS Testing ......................................................................................................117 5. CONCLUSIONS ...............................................................................................................120 6. REFERENCES ................................................................................................................123 7. ANNEXES ........................................................................................................................124 7.1 Arduino Code ............................................................................................................124 7.2 Conductivity Measurement of Propellants ................................................................. 129 7.2.1 EAN ...................................................................................................................130 7.2.2 Emi IM ...............................................................................................................131 7.2.3 Emi BF4 .............................................................................................................13 2 7.2.4 Emi TF ...............................................................................................................133 7.2.5 TES ...................................................................................................................134 7.2.6 Formamide G .....................................................................................................135 7.2.7 Formamide H .....................................................................................................136 7.3 Time-Of-Flight Measurement ....................................................................................137 iv 7.3.1 TOF Formulae ...................................................................................................137 7.3.2 Relation between Needle Voltage and Voltage at source ...................................140 7.3.3 Programming Codes developed .........................................................................141 7.3.4 Measurement of Thrust and Specific Impulse ....................................................153 7.4 Dimensions of thruster head .....................................................................................169 v LIST OF TABLES Page Table 1. Liquids whose conductivity is measured ....................................................................... 7 Table 2. Conductivities of some liquid propellants to be used in Colloidal Thrusters .................. 8 Table 3. Characteristics of Liquids used for TOF experiment. ...................................................19 Table 4. Voltages to be applied to the emitter and the extractors for turning ON/OFF the electrospray ..............................................................................................................................73