Linear burn rate of green ionic liquid multimode monopropellant

Multimode space propulsion systems are being proposed that integrate high specific impulse electric propulsion and high thrust chemical propulsion. The most important attribute of this concept is a shared propellant capable of both modes of propulsion, which enables mission flexibility. One promising approach is a catalytic monopropellant thruster paired with an electrospray electric thruster. Previous research has identified a green double-salt ionic liquid consisting of 41% wt. 1-ethyl-3-methylimidazolium ethyl sulfate and 59% wt. hydroxylammonium nitrate as a promising propellant candidate. In this work, the burn rate of this monopropellant is measured through pressure-based and high-speed imaging methods in a fixed-volume chamber pressurized across a pressure range from 0.5 to 10 MPa. Its performance is benchmarked by 80% wt. hydroxylammonium nitrate-water and nitromethane propellants. The burn rate of the multimode monopropellant is found to follow an exponential law given by r_b=5.35exp1.11P between 0.5 and 3 MPa and is approximately constant at 142 ± 29 mm/s between 3 and 10 MPa.