  We consider the interplanetary trajectory design problem posed by the 8th
edition of the Global Trajectory Optimization Competition and present the
end-to-end strategy developed by the team ACT-ISAS (a collaboration between the
European Space Agency's Advanced Concepts Team and JAXA's Institute of Space
and Astronautical Science). The resulting interplanetary trajectory won 1st
place in the competition, achieving a final mission value of $J=146.33$ [Mkm].
Several new algorithms were developed in this context but have an interest that
go beyond the particular problem considered, thus, they are discussed in some
detail. These include the Moon-targeting technique, allowing one to target a
Moon encounter from a low Earth orbit; the 1-$k$ and 2-$k$ fly-by targeting
techniques, enabling one to design resonant fly-bys while ensuring a targeted
future formation plane% is acquired at some point after the manoeuvre ; the
distributed low-thrust targeting technique, admitting one to control the
spacecraft formation plane at 1,000,000 [km]; and the low-thrust optimization
technique, permitting one to enforce the formation plane's orientations as path
constraints.
