Two-photon Absorption Laser Induced Fluorescence Measurements of Molecular Iodine flow in a Micro-Thruster Resistojet

Resistojet thrusters are an attractive alternative to electrostatic propulsion systems since they deliver high thrust at comparable powers to traditional thrusters, require simple, low-voltage

components for operation, and are largely propellant agnostic. Given its large molecular mass and room-temperature solid state, iodine is a logical propellant choice for these thrusters.

However, investigating iodine with traditional diagnostics is challenging due to its reactive nature and low sublimation temperature; therefore, detailed investigations of iodine plume

morphology remain limited. Here, we demonstrate direct in situ, non-perturbative, laser induced fluorescence measurements of neutral molecular iodine in the plume of a resistojet thruster.

Molecular iodine is excited from ground state using 611.661 nm photons, and fluorescence is spatially resolved throughout the exhaust plume using a planar approach. Plume morphology for

a range of resistojet heater conditions are presented over the entire areal dimension of the exhaust..