Manifold manoeuvres in the dark

Oliver Morrison has a master's thesis: "Use of Manifolds in the Insertion of Ballistic Cycler Trajectories".

We have all been assuming a craft in orbit around Earth, or on Earth, to get to Mars by a Hohmann or cycler trajectory. From Earth to Mars, Hohmann is bad enough for delta-V and cyclers are worse. You must do a "direct burn" - against a trajectory of longer amplitude than a Hohmann would be. So high thrust; damn the impulse. Hence Zubrin's warning that Bush and Ibn Saud will soak you on the shuttle fee. Elon Musk is assuming as much, too; from getting straight off Earth into a Mars Hohmann with his Starship. I was talking up tethers not long ago to get from orbit on out, or even Orion from northern Baffin Island. Gravity wells are a pain, yo.

What Morrison offers which is new: if (somehow) we've started from [Solar-Earth's] L2 halo, and we're going not for one-and-done Hohmann but for "S1L1-B" (Earth-Mars n=2): we might save on delta-V at least on that cycler. Morrison wonders what if someone's got a spaceship factory up in L2. L2 is metastable and its halo will kick you out if not station-kept. Morrison says: if you want into a cycler trajectory, find the planet's station at solar L2 halo, disconnect the craft, and let the halo's manifold do the work.

Same might hold for L1, or for Lyapunov or Lissajous closer to the nexus; but Morrison's not looking at these. Earth-Moon L2 looks interesting, as well. Morrison cited R. P. Russell and C. A. Ocampo but not, I think, 2006 "Optimization of a Broad Class of Ephemeris Model Earth-Mars Cyclers"; they'd endorsed S1L1 and Aldrin, adding only another n=2 "8.049gGf2" to be launched July 2042.

My site is all about SVL2 so... Venus-Earth might have a non-Hohmann cycler analogue. [UPDATE 3/1: If we ever get a delta-V under 10 km/s...]

This implies that high-mass cycler construction be done in L2, whence delta-V costs are least; and that low-mass shuttles should take Earthlings (and Loonies, and Venerean-orbitals) to L2. Once off L2 the cycler doesn't return to L2, because drrrr it's a cycler which needs gravity-wells to correct its trajectory.