A monopropellant includes 30-70% by weight of an oxidizer including hydroxylammonium nitrate, 5-50% by weight of a fuel, and a burn rate modifier in a non-zero amount of up to 3% by weight. The burn rate modifier can be selected from vanadium salts, iron salts, and combinations thereof. The monopropellant is a stable liquid between −20 C and 100 C at ambient pressure.