Propulsion technology development over the past half-century has produced numerous products-solids, cold gas, liquids, hypergols, monopropellants and combinations of the above. Each offers merits and optimal applications based on induced specific impulse (ISP), weight, size, throttling capability, center of gravity etc. Several Ballistic Missile Defense Systems (BMDS) have baselined liquid fuel based DACS (Divert Altitude and Control Systems) for the kill vehicle (KV). Monopropellants offer additional benefits over bipropellants due to the simplified engine complexity and reduced hardware requirements and/or heavier payloads. Hydrazine is a proven monopropellant widely used in missile and spacecraft propulsion systems. However, it is desirable to reduce the cost and health-risks associated with transporting, storing and handling hydrazine due to its high vapor toxicity. Ionic Liquid monopropellants based on hydroxylammonium nitrate (HAN) are being promoted as potential replacements to hydrazine based on reduced toxicity, increased energy density and specific impulse. Ogden Engineering & Associates, LLC (OE&A) has teamed with the University of Alabama in Huntsville (UAH) to improve the combustion efficiency and burning rate of HAN and HAN/HEHN based monopropellants. This effort stems from the successful development of a HEHN-based hypergolic green fuel (HGF) that OE&A has created in partnership with UAH.
Keywords: improved monopropellant combustion efficiency, ionic liquids, increased han burn rate
