Green liquid propellant oxidizers basing on solutions of ADN and an in commercial hydrogen peroxide for hypergolic propellants

Hydrazine replacement in hypergolic rocket propulsion systems requires new green oxidizers. In this paper an approach is investigated basing on commercially available concentrated hydrogen peroxide with purities from 60% to 80%. In scope to reduce the melting or glass transition temperature and to increase stability and to prevent ageing without ruining the oxygen balance, ammonium nitrate (AN), ammonium dinitramide (ADN) and urea hydrogen peroxide (Carbamide) were solved in hydrogen peroxide. Such oxidizers enable low operation temperatures far below -40 °C. They were tested as hypergolic propellants in combination with an energetic ionic liquid (EIL) basing on AMIM DCA as fuel including appropriate catalysts enforcing hydrogen peroxide decomposition. Such systems provide a theoretical specific impulse up to 2500 N s/kg or 3300 N s/dm3 and should suite as liquid or gelled propellants. Hypergolic lab scale ignition tests result in ignition delay times comparable to hypergolic systems in operation. The results were discussed in view of thermodynamic reaction data and measured temperatures. Especially it was found that the ignition delay time correlates with the inverse of the decomposition temperature of the oxidizer.