Green bipropellant development – A study on the hypergolicity of imidazole thiocyanate ionic liquids with hydrogen peroxide in an automated drop test setup

Conventional hypergolic propellant combinations, using hydrazine and its derivatives as fuels dinitrogen tetroxide based oxidizers, have been applied in spacecraft for attitude roll control systems more than 50 years. However, due to their high toxicity carcinogenic potential, investigations into alternative green propellants are an active field current research efforts. Promising candidates combinations of hydrogen peroxide suitable room-temperature ionic liquids. In this work, imidazole thiocyanate liquids tested drop tests with peroxide. For purpose, a newly developed automated test setup was designed implemented. As result, 1-ethyl-3-methylimidazolium (EMIM SCN) 1-butyl-3-methylimidazolium (BMIM turned out be highly concentrated (96.1%). The ignition delay time on average is 31.7 ms EMIM SCN 45 BMIM SCN. Theoretical performance the two calculated NASA CEA compared conventional combination (monomethyl hydrazine/dinitrogen tetroxide). specific impulse nearly 5% lower, but density increased by 10%. Furthermore, reduced dissolving catalytic additive, copper thiocyanate, lowest 13.9 achieved 5 wt% thiocyanate. higher concentration not further reduced. fuel pure were characterized thermal spectroscopic methods. Fluid properties like density, viscosity surface tension also determined laboratory investigations.