PROTOTYPING AND OPTIMIZATION OF A MINIATURE MICROWAVE-FREQUENCY ION THRUSTER
Open Access
- Graduate Program:
- Aerospace Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- March 22, 2018
- Committee Members:
- Sven Bilen, Thesis Advisor/Co-Advisor
- Michael M. Micci, Thesis Advisor/Co-Advisor
- Amy Ruth Pritchett, Committee Member
- Keywords:
- space propulsion
- plasma propulsion
- propulsion
- electric propulsion
- rocket propulsion
- ion engines
- microwave thruster
- ion thruster
- experimental research on electric propulsion
- computational research on electric propulsion
- miniaturization of electric propulsion
- ion thrusters for CubeSats
- electric propulsion for CubeSats
- Abstract:
- This thesis presents progress on the development of the Miniature Microwave-Frequency Ion Thruster (MMIT), currently being developed at Penn State as a microthruster with high specific impulse that can be used on small satellites for station keeping, attitude adjustments, and modest delta-V maneuvers. The MMIT works by generating a microwave electron cyclotron resonance (ECR) discharge plasma, then accelerating ions through a series of electrostatic grids. Using argon as the propellant, the MMIT can start with as low as 2.6 W of total absorbed power from a 4.98-GHz coaxial input power source. For the current MMIT iteration, our research thrusts have been threefold: demonstrating plasma generation; sustaining and containing the plasma; and extracting the ion beam. We have largely focused on optimizing the geometry of the magnets and antenna used for ECR plasma generation; defining the geometry of the chamber for containment of the plasma; and developing grid geometries for efficient beam extraction. Progress to date toward a functional prototype has leveraged numerical simulations and experimental measurements on the proof-of-concept design, which we are currently further optimizing. A Langmuir probe is used to measure ion density and temperature in the plume as well as beam current, and a Faraday cup is used to measure the current density of the beam. The measurements obtained from these probes are used as the basis for determining a calculated thrust for the MMIT.