Fry-by

On any given planet, there will be visitors who desire a swift return to their home planet. Rather than sit for the next Hohmann ride, the alternative is to leave on the "opposition" track: down toward the Sun, and around it, to get back home.

Here we are always talking about outer planets, inbound. The MS(v)E / ME debate started as an evaluation of two no-energy trajectories - outside Mars and Earth gravity wells, leaving aside internal energy requirements (i.e. life support). MVE, in the Opposition Class, was picked so as to use innerplanet Venus to slow the craft down, for reentry into Earth's well. Earth has used inner planets itself ... to speed craft up: that was Cassini on EVS (EV/VEJS, to be exact). Venus is involved here, literally, as tangent only.

Mars-by-Sun-to-Earth, which is the Opposition Class route best studied, has its departure scheduled about thirty days after arrival. Such is the Fry-By, to cite Zubrin; longer than Hohmann and more-irradiated. UPDATE 2/7/21: When SVL2 gets that moving tether, so much more so. There's also Earth-by-Venus-to-Venus; V_∞ at our sister being sometimes a problem, especially if you want the Venus orbit to be reasonable.

Such trajectories tend to target Venus en route. Most are to slow the vessel down, for energy-savings on return home (or to a rounder Venus orbit); they might even consider aerobrake below 150 km altitude. That means, Venus is in position for Hohmann up to the destination planet, historically our good green Earth. Some craft - like Cassini - would rather speed up, so will steer (barely) above the exosphere. Either way it's all about the Delta V.

Although posing some danger for satellites here, the Fry-By encourages to dump ores and passengers into Venus orbit, if there's means there to catch them. For the Fry-By itself the drop in mass can offset the known energy-worries around the Delta-V.

I do assume they transfer personnel and materiel into orbit, not directly into Venus' atmo. The flyby is always greater than escape velocity let alone orbital. And to remind: that's why it's here, to use a large planet's gravity without staying in orbit.

The Martians tell me that the first Earth-exiting missions may rely on the Fry-By for return, because those Earthlings prioritise not being away from Earth too long. And Venus will like it - until the mines' mass-drivers are firing on Ishtar, new metallics are always welcome.