Hot firing of a N2O/C2H4 premixed green propellant: First combustion tests and results

Today hydrazine is the commonly used monopropellant for attitude- and orbit control of satellites and for powering probes or landers. Due to changing political and economic framework, (e.g. the REACH regulation in Europe) different propellants for replacing hydrazine are currently under development or qualification. The Institute of Space Propulsion of the German Aerospace Center (DLR) at Lampoldshausen is focusing on two different propellants to replace hydrazine: ADN-based monopropellants and mixtures of nitrous oxide with hydrocarbons. The latter are so called premixed monopropellants: oxidizer and fuel are stored in a premixed state in one tank. Thus the simplified propulsion system of a monopropellant can be combined with the high ISP of a bipropellant. To gain experience with a propellant mixture consisting of nitrous oxide (N2O) and ethene (C2H4), DLR is conducting hot gas combustion tests with an experimental combustor. The paper summarizes the results of combustion tests conducted with the premixed propellant injected in gaseous state. Calculated and measured performance (c* and