Modified electro-thermal thrust augmentation for mini-satellite applications

A modified concept, patent pending, has been applied for thrust augmentation of small mono-propellant hydrazine thrusters by means of internal ceramic heater, defined here as Ceramic Heater for Augmented Thruster - CHAT. The thrust level is in the range of 0.5N to 0.25N, with corresponding specific impulse of 270 sec to 300 sec. The thruster is mainly designated for delta-V missions for mini and micro-satellites applying long steady firing. The nominal electrical power is relatively low, i.e. 300W although even for 200W, improved performance can be obtained. CHAT combines catalytic hydrazine decomposition with heating of the gaseous products by an electrical resistance heater, which results in enhanced specific impulse. The new design consists of a heater module located within the thruster itself, made of Silicon Carbide ceramics. Integrating the heater module within the same envelope as the decomposition chamber, simplifies the thruster design, while lowering thruster weight, reducing cost, and decreasing thermal losses. The compact design enables operating the thruster during periods of limited power in a pulse-train mode with variable duty-cycle at a minimal performance penalty.