H2O2 and HAN Green Monopropellants—A State-of-the-Art Review on Their Recent Development, Corresponding Synthesized Catalysts, and Their Possible Use as Thrusters

This review provides a state-of-the-art and up-to-date analysis of the design and development of green monopropellant thrusters based on hydrogen peroxide (H2O2) and hydroxyl ammonium nitrate (HAN) as high-energy compounds for reaction control maneuvering of satellites. In summary, we introduce the new concept of Green Liquid Propellants (GLPs) that can serve as eco-friendly alternatives to conventional hydrazine thrusters. GLPs offer several advantages, including low toxicity, acceptable thermal decomposition and combustion behaviors, low onset temperatures of decomposition, stability, and long-term storability, compared to hydrazine. H2O2 exhibits a low onset temperature; however, its storability does not match that of hydrazine. On the other hand, HAN boasts excellent storability; however, it comes with a higher onset temperature when compared to hydrazine. This review provides critical insights into the recent advancements in H2O2 and HAN thrusters, along with an examination of the corresponding catalysts. The focus is on their application for the long-term maneuvering of satellites. We have chosen H2O2 and HAN formulations to focus on these two GLPs due to their extensive use by various space agencies worldwide. Moreover, the future directives of both selected green propellants were discussed for potential applications. Finally, the choice between H2O2 and HAN depends on the specific requirements of the propulsion system, taking into account factors such as performance, environmental impact, safety, and operational considerations. Each propellant has its advantages and challenges, and ongoing research aims to address some of the limitations associated with these green propellants.