Life cycle sustainability assessment of monopropellant propulsion systems: advancing the comparison between conventional and novel monopropellants

Within the field of monopropellant chemical propulsion, hydrazine has been the industry standard for over 50 years. During the past three decades, this has been challenged by the development and adoption of so-called novel monopropellants, which feature a lower propellant toxicity while delivering equal or improved performance compared to hydrazine. This replacement of hydrazine is aimed at reducing the operational hazards and costs related to propellant fuelling and handling and is additionally motivated by the uncertain regulatory future of hydrazine in Europe. At this point, several novel monopropellants have been proven in orbit to provide performance improvements with respect to hydrazine at a lower overall cost. Still, the comparison of these technologies remains mostly limited to propellant toxicity, performance and total system cost, neglecting other elements which may greatly influence the sustainability of the entire propulsion system. This constitutes a significant knowledge gap, not only because o