Feasibility Study of NOFB Propulsion Systems for Multi-Altitude Earth Observation Missions

Earth observation (EO) satellites represent the largest and fastest growing segment of the satellite industry [1]. Higher imaging resolution can be achieved either by enlarging the optical system-which increases satellite dry mass-or by lowering operational altitude, where increased atmospheric drag demands continuous propulsive orbit maintenance[2]. At Low Earth Orbit (LEO) and Very Low Earth Orbit (VLEO), atmospheric drag increases significantly, requiring a dedicated propulsion system for sustained orbit maintenance. Hydrazine (N2H4) has been the conventional propellant choice, but its high toxicity incurs substantial handling costs, and its low vapor pressure necessitates a separate pressurant tank. Nitrous Oxide Fuel Blends (NOFBs), which utilize nitrous oxide (N2O) as an oxidizer, have emerged as a promising alternative, offering non-toxicity, self-pressurization, and comparable specific impulse. This study conceptually compares Hydrazine and NOFB propulsion systems by estimating propellant mass, tank volume, and system mass for an EO satellite mission.