Low energy transfers have shown that it is possible to reduce the ∆v cost (and therefore the propellant mass) for a number of transfer types. This is possible by exploiting the natural n-body dynamics characterizing the spacecraft motion within the Solar System. In particular, the concept of ballistic capture makes it possible to reduce the hyperbolic excess velocity upon moon/plant arrival, and allows the spacecraft to perform few orbits at zero cost. Low energy transfers are designed by using impulsive maneuver, and therefore they inherently use chemical propulsion (Figure 1). On the other hand, solar electric propulsion (or SEP for brevity) entails considerable savings in the propellant mass thanks to its high specific impulse. Nevertheless, fully SEP interplanetary and lunar transfers suffer from the long durations needed to achieve escape, which may even lead, in some cases, to discard this option.