Flight-Weight Ceramic Composite Monopropellant Rocket Thruster Assembly

Rocket thrusters based on hydroxyl-ammonium nitrate (HAN) monopropellants are of interest for Network Centric Airborne Defense Element (NCADE) missile axial and divert propulsion applications because of their inherent system simplicity, low toxicity, high specific impulse (~275s), and 50% greater density-specific impulse over hydrazine (Isp»220s). Their high combustion temperatures (³3300°F), however, pose significant challenges on chamber and bedplate materials. In order to exploit the performance benefits of HAN, advanced materials, such as SiC composites, reticulated SiC foams and lightweight end-closure joining methods are needed. SiC composite and SiC foam catalyst bedplates have demonstrated superior performance qualities in recent hot-fire testing at AEROJET, while significantly decreasing weight and manufacturing cost over alternative designs and materials. Hyper-Therm HTC’s SiC composite thrust chambers and SiC foam bedplates have been selected by AEROJET for several MDA missile applications, however composite chambers have not yet been demonstrated using HAN. Moreover, a method for efficiently joining the composite chamber to the metallic forward end-closure is essential to the success of affordable flight-weight composite propulsion devices. The objective of this program is to develop a flight-weight composite monopropellant rocket thruster consistent with the requirements of NCADE for hot-fire evaluation. High-performance SiC composite thrust chambers incorporating ultra-lightweight SiC foam catalyst bedplates and utilizing a weight-efficient end-closure joining method will be developed in Phase I and prepared for hot-fire testing by AEROJET using HAN early in a Phase II program.