Effect of propellant on design parameters of spacecraft with electric propulsion system

The paper presents results of a study of how the propellant used in an electric propulsion system (EPS) affects design parameters of a spacecraft. The transportation problem that was considered consisted in the transfer of a spacecraft with the initial mass of 18 tons from low Earth orbit to circumlunar orbit. The total delta velocity was assumed to be 8 km/s. The spacecraft design parameters were determined at the optimal EPS specific impulse using payload maximization as the criterion. The effect of the propellant was expressed through the EPS parameters that are directly determined by the type of the propellant: the storage and feed system mass efficiency factor, which is numerically equal to the ratio of the storage and feed system dry mass to the propellant mass; EPS efficiency; electric power for heating and keeping the propellant at the required temperature. Considered as propellants are substances that are gases, liquids, and solids under normal conditions. Calculated were the following SC parameters: relative mass of the payload; power system output; the limiting value of the power system specific mass at which the transportation task is still feasible.