Hypergolic propellants are easy to start and restart, stay liquid at normal temperatures, and avoid storage issues, making them ideal for spacecraft propulsion systems. However, conventional hypergolic propellants are toxic, prompting the need to find safer alternatives and/or reduce their toxicity. The growing demand for propulsion in advancing space technology has driven research into high-performance, sustainable, and environmentally safe hypergolic propellant types. At this point, research into new hypergolic fuels that can replace traditional rocket propellant designs is highly significant. In this study, the current status of hypergolic fuels is discussed, and new technological developments and future projections are examined. Several approaches have been studied in an effort to create a high-performance hypergolic propellant system. These include modifications such as changing the structure of propulsion systems, altering propellant constituents, and adding additives. All these conditions were found to bear a profound effect on the specific impulse, density impulse, heat energy, and ignition delay of the propellants.
Yılmaz et al. (2025) studied this question.