Development and characterization of ceramic micro chemical propulsion and combustion systems

This paper reports on the development of a liquid monopropellant microthruster utilizing electrolytic ignition. Low temperature co-fired ceramic tape technology was used to fabricate the microthrusters. The microthrusters had integrated silver electrodes to enable ignition of hydroxylammonium nitrate based liquid monopropellants by electrolytic decomposition. The volume of the thruster combustion chamber was 0.82 mm³. The microthruster was successfully ignited, and a thrust output of approximately 200 mN was measured with a voltage input of 45 V. Energy input as small as 1.9 J was achieved for ignition, and ignition delay as short as 224.5 ms was recorded. Ignition delays were found dependent on the type of HAN-based propellant, the voltage potential, and the size of the electrodes within the combustion chamber. When ignition was rapid, some cracking of the thruster body was observed.