Small-Scale Planar Nitrous Oxide Monopropellant Thruster for “Green” Propulsion and Power Generation

Research is ongoing at Stanford University on the catalytic decomposition of nitrous oxide as an environmentally friendly monopropellant for propulsion and power applications. Two meso-scale planar monopropellant thrusters have been successfully tested: one made of monolithic silicon carbide utilizing a commercially supplied catalyst, and the other made of Hastelloy-X ® utilizing a rhodium based catalyst prepared in-house. The unique planar geometry shows a pathway towards scaling down to micro-scale through MEMS-batch fabrication techniques which enable low-cost, mass produced devices with improved thrust to weight ratios and faster start-up transients. The in-house catalyst showed higher reactivity as compared to the commercially supplied catalyst by initiating the decomposition reaction at a temperature of 200°C corresponding to 50W input power. Bed loadings up to 8.67 kg/m 2 /sec were achieved at a cstar efficiency of 71%. Both devices are compared to a previously reported, scaled-up, cylindrical thruster.