Platinum Catalysts Development for 98% Hydrogen Peroxide Decomposition in Pulsed Monopropellant Thrusters

A number of platinum catalysts for the decomposition of 98% hydrogen peroxide, based on different substrates, geometries, and sizes, have been prepared using different procedures. The catalysts have undergone a set of dedicated tests for screening their catalytic activity and their thermomechanical resistance in order to identify the most efficient and suitable catalyst to be used for a pulsed monopropellant propulsion system. An experimental test campaign on a 20 N monopropellant thruster prototype has been carried out with the aim of assessing the capability of the finally selected new Pt/alpha-Al2O3 catalysts of effectively decomposing 98% hydrogen peroxide and the attainable propulsive performance in steady-state conditions for the future assessment of the propulsive performance of the intrinsically unsteady new propulsion concept. The catalysts have been able to decompose up to 1 liter of98% H2O2 with very good efficiencies (hc* > 95% and h Delta T >= 90%) and without any pellet breakage or catalytic degradation. The thrust profile has been particularly smooth and the experimental specific impulse measured at sea level with the matched conical nozzle has been 130 s, which corresponds to an extrapolated vacuum specific impulse for a high-expansion-area- ratio bell-contoured nozzle higher than 185 s.