Energy and mass model and parametric optimization of a reusable electrically-propelled space tug for payload delivery from Earth orbit to Lunar orbit and from Lunar orbit to Earth orbit

The paper presents math models and optimization results for key parameters of a Reusable Orbital Transfer Vehicle (ROTV) with a nuclear-powered Electric Propulsion System (EPS) aimed at maximizing total payload mass delivered on an Earth-Moon-Earth round trip (from Earth orbit to lunar orbit and from lunar orbit to Earth orbit). Examined was the impact of payload mass ratios during transits Moon-Earth and Earth-Moon on the optimal parameters of ROTV (electric power, EPS specific impulse, transit time, number of trips, EPS propellant consumption), that maximize payload delivered on Earth-Moon-Earth trips over the EPS design life. It is demonstrated that in the absence of constraints on transit time, ROTV initial mass on the trip from the Moon, EPS specific impulse, power module output, the curve of the values of the maximum total payload mass delivered on an Earth-Moon-Earth trip stays within the range that has the lower boundary which corresponds to the case where the cargo is only transported to the Moon, and the upper boundary which corresponds to the case where the cargo is only transported from the Moon.