Short Overview on the Development of Advanced Green Monopropellants for Satellite Propulsion Applications—Status Summer 2025

In the last three decades, significant progress has been made to find, develop, test, and qualify advanced green monopropellants which have the potential to replace hydrazine in satellite propulsion to a large extent due to their lower health risks, environmentally friendliness, and interesting or even better performance properties. Some ADN- and HAN-based monopropellant blends have meanwhile reached high TRL levels. The ADN-based blend LMP-103S, is an energetic ionic liquid (EIL) and is used onboard more than 25 satellites. It was the first green EIL used in space and currently has the most applications. HAN-based monopropellant blends like AF-M315E also have several applications on satellites. Nevertheless, intensive research and development activities are furthermore conducted on the way to a mature green propulsion technology base and to identify and test further species and monopropellant mixtures, which could or seem to promise even better properties and may have also the potential to replace hydrazine. This paper provides an overview on the properties of developed monopropellants and interesting candidates for orbital satellite propulsion in the thrust range up to approximately 200 N. It discusses types of monopropellants, used species, and mixtures broader than in previous review and overview publications listed in the Introduction, and considers the status up to summer 2025.