Electrothermal propulsion system for a nanosatellite

The paper presents principal results of an effort to develop an experimental pulsed mode electrothermal propulsion system with self-oscillating operation. Selected as propellant was water doped with ethyl alcohol to prevent freezing. Specific impulse of the propulsion system thrust and delta velocity were calculated for various alcohol concentrations. The propulsion system structure and control system were developed and built. Also developed and built was a system for measuring key parameters of the propulsion system: thrust, thermal state of the heater, as well as the voltage across the intermediate energy storage unit - a bank of supercapacitors. An automated system for conducting an experiment was developed and implemented on a control computer. It was proposed to use for the propulsion system a self-oscillating operational mode which had been experimentally proven to be highly efficient. The experiment was run for the propellant that contained a 40% by mass of alcohol dopant, which made it serviceable in virtually all near-Earth orbits. Specific impulse of 1300 m/s was obtained at average power consumption of no more than 1 W with virtually complete engineering and environmental safety through all the phases of the life cycle. The key design solutions were patented in the Russian Federation. This propulsion system may serve as prototype for developing a flight model of the propulsion system for a nanosatellite.