Lunar transfer vehicle design issues with electric propulsion systems

This paper describes parametric design studies of electric propulsion lunar transfer vehicles. In designing a lunar transfer vehicle, selecting the 'best' operating points for the design parameters allows significant reductions in the mass in low earth orbit (LEO) for the mission. These parameters include the specific impulse, the power level, and the propulsion technology. Many of the decisions regarding the operating points are controlled by the propulsion and power system technologies that are available for the spacecraft. The relationship between these technologies is discussed and analyzed here. It is found that both ion and MPD propulsion offer significant LEO mass reductions over O2/H2 for lunar transfer vehicle missions. The recommended operating points for the lunar transfer vehicle are an I(sp) of 5000 lb(f)-s/lb(m) and a 1 MW power level. For large lunar missions, krypton may be the best choice for ion propulsion.