Challenges for Alternative Propellant Electric Propulsion: Diagnostics and Test Facilities*

Electric thrusters that are capable of operating on a wider variety of propellant types (e.g. monopropellants, solid metals, water, etc) have the potential to significantly reduce the overall electric propulsion (EP) system mass and complexity for a variety of satellite missions. The challenges of operating on new types of propellant must be solved using comprehensive analytical and experimental research efforts. However, many of the diagnostic methods presently used to gather insight into the operation and optimization of EP systems require simple propellant types (e.g. noble gases). Furthermore, traditional diagnostics aren’t well-suited to characterize plasma chemistry of complex propellants. In addition to the diagnostic challenges, ground test facilities must be equipped to handle operation on different propellant types. This talk will review the challenges of diagnostic development and ground testing of electric thruster operating on alternative propellant types. Emphasis will be placed on relevant, emerging techniques from across multiple areas of low-temperature plasma science.