Instead of sending one rocket, you send two. You link them with steel cables. Then you rotate them around to generate the required gravity.
From
Mars Direct: A Simple, Robust, and Cost Effective Architecture for the Space Exploration Initiative, by Robert Zubrin, February 1991
DOI:10.2514/6.1991-329
A relatively cheap (for space) setup to get some good actual measurements.
https://en.wikipedia.org/wiki/Advanced_Resistive_Exercise_De...
Your great grand kids might eventually cope.
Muscle mass is so vital for long term health. 70-year-olds confined to bed rest for just two weeks have been observed to lose significant muscle mass that they most likely will never get back.
Obviously most astronauts are younger than 70. But they're also losing a lot more muscle mass and bone density.
A spinning drum is probably the best method short of artificial gravity, but it has a couple problems. A rotating reference frame creates some pretty non-intuitive effects (https://www.youtube.com/watch?v=bJ_seXo-Enc). Research is ongoing about just how fast a human can be spun for a long duration, although data is hard to come by. We also don't know how low of a gravity a human can stay healthy in without intervention like serious exercise. If it turns out that you need 1G, that involves a much larger spinning drum than a G/3 (Mars) or G/6 (Moon) environment. The problem is that we really have no way to simulate those environments for a human.
So you'd have Mars G for time on the surface anyway.
And besides: a few astronauts have already done long duration microgravity, returned to Earth & lived to tell.
It's a valid hypothesis. Humanity would need to have an entire engineered biosphere to replace the biome living in our guts, our eyes, our . . everywhere. And anywhere we find that's close enough to Earth to live in, will have . . something else . . almost certainly[1] already there.
Kim Stanley Robinson isn't an easy read if you're on the other side of the political spectrum, but Aurora is comparatively free of his standard preachiness, at least in my ears. I actually disagree with his primary thesis of Aurora, and the novel suffers from some fundamental problems as a story, but the point is still salient. Humans will have to build their own Earth, wherever they end up, either out there or back here. I have a funny feeling we won't learn to treasure our own planet until we find out how much work it is to live on another.
[1] Particularly given the extraordinarily early date of the first Terran lifeforms. It doesn't seem to take too much to get the ball rolling, unless the panspermia theories actually turn out to hold some water.
*No* place is going to be "close enough" to Earth to live in: the closest star system is 4 light-years away, and will take tens of thousands of years to travel to with anything remotely like current technology. The only way we're going to find another planet "close enough to Earth to live in" is if we invent a real, working, practical FTL drive. That's not terribly likely. Well, there is one other possibility: some glowing blue alien substance called "protomolecule" is discovered in our solar system and somehow (through a long, twisting plot arc) takes over an asteroid with 100k people, assimilates their biological matter, crashes on Venus, then travels to the outer system and builds a Ring Gate. Anyway...
Basically, we're stuck with this planet, the not-at-all-like-Earth worlds near it, and the other resources of this system.
The only real way we're going to create a viable, Earth-like colony is to build an O'Neal Cylinder.
Aurora uses the generation ship model of transport, which . . does not go ideally. Many problems unforeseen for hundreds of years of travel in the utter empty (you hope desperately that it is empty). It's also a fast but not relativistic ship, .07C, at exorbitant energy costs. Hope you like the moon / mercury covered in purple lasers. Relativistic lower-mass vessels with the same technology, I guess, but the impact threat goes through the roof, and it's not a settlement ship. A better way to make the Aurora-style project is a small ship with frozen embryos that get birthed insitu by machines of loving grace. Then you can go faster, smaller.
But it's all talk talk. We're technically capable of doing these things, but I'm not sure we're socially capable of even lunar settlement at this stage of our history. Let alone Mars, the outer system. The Expanse was, in its own way, optimistic about our future. They just had to get medieval to get Earth's gas balance (and probably phosphorous! and who knows what else) back in the normal range.
Heh heh you know it's funny but if we took the solar system as it exists right now, a floating settlement higher up in the Venutian cloud layers would be closest[1] to fitting that bill, in terms of kgs of crap you need to carry around outside with you. Just, yknow, not anyone's typical idea of a "settlement".
[1] And yet so very damn far away.
That is not the only way, extending lifespan would work as well
Optimistic! I have a feeling we won't learn to treasure our own planet until we fail to reach another. The problems here are simply too massive for us to coordinate spreading to other places.
