Mars transport name?

I think the most feasible idea for a mars trip or mars colonization or
trade etc. would be to find an asteroid that frequently crossed paths with
Earth's orbit and mars's orbit and dig into it. Such a habitat would not be
a very good one, but it would be very satisfactory for making the long trip
and carying cargo. It would also be the most safe. Anyway, I think I once
heard this kind of object called something special, does anyone know what
that name was? You're probablythinking of Aldrin's proposal for Mars ships following such paths which he called Cyclers. Cyclers would save a lot of fuel over accelerating and decelerating the entire ship again and again, but he was still assuming certain course adjustments at each end of the trip. It would be hard to repeatedly adjust the course of an asteroid like this, at least if it was of any significant size. There would really be no advantage to traveling on the asteroid unless you had a continuous ongoing need for very large amounts of new raw materials. I think closed life support systems would be a pretty good bet for a continuously cycling Mars ship. There's really no need todig into an asteroid for protection from meteoroids either; the actual threat is more modest than many realize. If seeking protection from cosmic rays, 6 feet of shielding is all you would need to safely spend an entire lifetime on the ship; anythingmore than this would be overkill.