Characteristics of transfers to and captures at Europa

This paper explores the characteristics (i.e. stability and performance) of transfers to, and captures at Europa. We focus on optimal low-thrust transfers from Ganymede to potential science orbits at Europa and compare different capture types, transfer resonances, and thrust accelerations. The two types of capture methods we consider are capture in a distant retrograde orbit (DRO) and capture by targeting a state on a stable invariant manifold of a halo orbit. We show that each type has its advantages and disadvantages. The first part of DRO-type capture may be easier than a halo-type capture in some design schemes because DROs are generally extremely stable. However, halo-type captures using stable invariant manifolds typically result in fewer escapes even when full ephemeris is used. Moreover, changing the inclination to achieve a high inclination science orbit at Europa is much easier in a halo-type capture. We study these trade-offs in this paper.