Is a Continuous Mars-Earth Transporter Using Gravity Assist Viable?

[Stormer]

TL;DR Summary

Can a spaceship continuously go between Earth and Mars with gravity assist at each end and minimal motor input with the current orbits of Mars and Earth?

I watched a movie a while ago (i think it was called Stowaway) where there was a craft with artificial gravity, and enough space for everyone's needs that was continuously going between Mars and Earth gravity assist slingshotting around them each passing. And then the crew just used a small spaceship with supplies and the minimum space needed for the crew to be to shoot up from Earth or Mars and dock to the "transporter" craft for a comfortable ride the majority of the trip.
This seemed like a really good solution where you can add all of the shielding, artificial gravity and so on to the transporter craft, and then keep the launch craft down to a minimal weight and size. But is it possible? Can you keep a craft in a continues trip between Earth and Mars with gravity assist slingshotting at each end with minimal motor input on the way indefinitely?

 

[Filip Larsen]

It's an interesting concept (but not one I have been researching as such). In principle it looks possible, but not without some tradeoffs.

You should be able to find some more information on the topic if you search for "Mars cycler" or similar. For instance, this 1986 conference paper on circulating transport orbits between Earth and Mars dig into some candidate cycler orbits and the Mars cycler Wikipedia page also has some more references that looks interesting.

Edit: Another 2002 conference paper, Analysis of a Broad Class of Earth-Mars Cycler Trajectories, is perhaps giving a better overview of the orbit types.