With the ability to lift more weight, it also means that the travel time to Mars could be shortened considerably (by using more propellant).

The minimum propellant travel times are a major barrier.

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ethbr1 5 days ago | parent [-]

Question for the audience, because I've always been curious.

Have there ever been any historical plans for a permanently-transiting interplanetary craft?

A large craft is built, accelerated up to speed (since time wouldn't be a factor, high Isp/low-thrust engines could be used), then left looping between Earth and X at constant high speed, with smaller (and shorter-term) craft accelerating to meet it (e.g. underway replenishment with crew and fuel transfer) or decelerating at the destination.

Heck, if you've got something optionally-crewed, you could have it continuously burning for years to build up speed.

Or do solar system astrodynamics make waiting and then burning like hell from orbital speeds during optimal transit windows more efficient?

	▲	schiffern 5 days ago \| parent \| next [-]
		Yup, someone thought of it. That man's name? Buzz Aldrin. https://buzzaldrin.com/space-vision/rocket_science/aldrin-ma... https://web.archive.org/web/20101102073607if_/http://buzzald... It is indeed more efficient to perform the usual Hohmann transfer, but the advantage of the Aldrin Cycler concept is you can accelerate a large vehicle once and then 'amortize' that over multiple trips.
	▲	ahazred8ta 5 days ago \| parent \| prev [-]
		The problem with an Aldrin Cycler https://en.wikipedia.org/w/index.php?title=Aldrin_cycler is that you pretty much have to leave it unoccupied for several years at a time because the planets are in the wrong place on most orbits. Then after 20-30 years the gaskets start to leak and the electronics get glitchy. Look up how much elbow grease it takes to replace the expired components on the ISS over a 5 year period.