Investigation on Ionic Liquid Combinations as Fuels for Hypergolic Propellants with Hydrogen Peroxide

One of the most promising approaches for alternative hypergolic propellants for the New Space sector is the combination of hydrogen peroxide as oxidizer and ionic liquids as fuels. Ionic liquids are particularly characterized by their negligible vapor pressure, high density and flexible cation design. Upon these characteristics, they can offer advantageous properties for future space propellants. This work focuses on the combination of two ionic liquids whose properties complement each other advantageously. The fuel named HIM_35 ignites with a delay of 16.7 ms with H2O2. The fast ignition of this hypergolic bipropellant is particularly remarkable, considering the fact that it does not comprise any transition metal or hydride-based additives. As the calculated volumetric specific impulse ρ Isp, max of 429 s·g·cm−3 of HIM_35 with H2O2 exceeds the value of the conventional hypergolic propellant combination MMH/NTO under the same circumstances, it is an auspicious alternative “green” hypergolic bipropellant combination