Researchers propose ballistic capture as cheaper path to Mars (phys.org)

I doubt it would work in KSP - as far as I can tell, it depends on using the gravitational pull of the target body to slow down while still outside of its SOI. KSP uses a simplification where it ignores the gravitational pull of all bodies except the one in whose SOI you currently are. (AFAIU, this is mostly to simplify the mental model for players, though there are also performance benefits.)