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Reading idlewords' blog (specifically https://idlewords.com/2025/02/the_shape_of_a_mars_mission.ht...) has convinced me that human exploration of Mars is infeasible without drastic advances in space propulsion. If the journey takes over a month it's not happening.
Why is a flight longer than a month problem ? It will be much longer, more like half a year one way.

On the other hand, uninterrupted (orbital) spaceflight record now stands at 437 days, so we know humans can do it.

The blogpost I linked makes a good case for why it's a problem.

A Mars mission with current technology will require supporting humans for 600-1000 days with no resupply or rescue possible. The current record is well short of that and they also had regular resupplies.

The communications round trip delay makes a big difference. Ground crews are able to handle a lot of routine system monitoring and maintenance for orbital and lunar spacecraft, freeing up astronauts' time and mental energy for critical tasks. A Mars mission takes away most of this useful help from the ground.

You might say "AI will do it" and this may be true 10 years from now. But software is notoriously hard to get perfect and on this mission there are no second chances.

437 days in LEO that is, where they're still protected from like 90% of cosmic rays. Hauling enough shielding is going to take a lot of energy, and inadequate shielding is worse than none.
It sounds not as bad as Moon dust. Realistically the Mars is about as habitable as the Moon, not habitable. So it’ll be a one-off problem.
The question in my mind in 2026 is how astronauts will walk on two legs.

Look at astronauts who exited the Gemini capsules or even the Space Shuttle orbiter, and see how they could, more or less, walk around and deal with Earth gravity.

Now, compare the ISS expedition astronauts. They are carefully extracted by a team of strong people. They are immediately placed on medical gurneys for transport. Nobody from ISS stands upright or walks unassisted. They will suffer vertigo, no matter what.

Furthermore, NASA restricts their activities for months afterwards. No jogging. They will be re-learning how to shower and brush their teeth! Any task that was different in microgravity will challenge them anew.

Now a Mars journey is 6 months, one way. There will be no spinning the capsule and no constant 1G acceleration with actual technology. So without science fiction, in the real world, astronauts would face a debilitating environment of zero-G that would reduce them to toddler status at their destination.

That, not dust, is the chief reason why Mars will continue as the domain of robots and automatons. I, for one, welcome them!

Well, Mars has 1/3 of earth gravity so that helps.

So for spinning the capsule, you only need say 1/5 earth gravity to be reasonably capable of walking on Mars.

Does that help?

The experiments recently done on mice on the ISS have concluded that, at least for them, around 1/3 of Earth gravity is the minimum required to preserve health.

So providing only 1/5 g for artificial gravity is likely to be insufficient.

Unfortunately, in the experiments with mice 1/3 g, like on Mars, was the minimum required to prevent severe health problems. For really having no health problems, 2/3 g was needed, i.e. more than on Mars.

There are chances that the exploration of the Solar System by humans will not really be possible otherwise than in very big spaceships with good radiation shielding and artificial gravity, which would allow humans to stay on them for an indefinite time.

Then for the exploration of Mars or of other planets, satellites or asteroids, such a big spaceship will stay in an orbit around that body and exploration teams will live on the surface only for short times, short enough to not be affected by the insufficient gravity.

It is likely that such big spaceships would be practical only when propelled by nuclear reactors, assembled in an Earth orbit, or on the Moon.

Or else, for living on Mars one would have to use underground bases where the habitable part would be rotating, to enhance the gravity.

You can't really spin a small spacecraft to get rotation gravity - the rotation period would make it unworkable.

However, you can connect two parts of your space craft with long cables and then spin the resulting contraption around its now center of rotation & the rotation period will be manageable.

This concept has been nicely demonstrated & quite well popularized by the recent Project Hail Mary movie.

The cheaper alternative to having 2 spacecrafts connected by a cable is to replace one spacecraft with a counterweight.

However, having 2 identical spacecrafts would be more reliable, as there would be more chances for at least one of them to remain completely functional over the entire duration of the journey.

> This concept has been nicely demonstrated

In a real spacecraft? With humans?

As I a say - a movie demonstrated how it would wourk & look like.

As humman spaceflight goes, spin gravity has not been demonstrated in space yet. IIRC they wanted to try that with Gemini, same as with an early jet-pack, never actually got to it during that program.

But effects of spin/circular motion have been demonstrated - Gemini 8 almost spun the crew to their death due to a stuck RCS thruster & Skylab astronauts made a video of them running around the inside of the big circular living space inside the station.

Build MarsX and hope they can one day get over to Earth
Since the gravity is so different on Mars, I assume eventually born-Martians will evolve differently from earthlings. They'll be taller and thinner and require less oxygen. One day, when earthlings and Martians mate, there's going to be a new species. How cool is that?
"The Expanse" (or: "Leviathan Wakes" by James S. A. Corey).

They talk about "living at the bottom of the well" within our solar system (gravity well, that is). Mars effectively "divorces" from Earth (no kings / 1776, plus they need to be 100% self-sufficient), casually called "Dusters" presumably due to the Martian dust.

People working on the asteroid-based bases (in our "Asteroid Belt") are called "Belters".

Then also read: "The Moon is a Harsh Mistress" by Heinlein, where humanity colonizes "Luna" and have "Loonies" for relatively obvious reasons.

Both books delve a bit into the physiological changes but also the socio-political ramifications of humanity in space, and both are _excellent_ reads!

Why would anyone want to move to Mars?

It's like moving to a desert.

yeah, we certainly have no examples of people moving to deserts on this planet, and even considering it a very attractive place to live :)
Well, frozen deserts like Northern Canada, Alaska or Siberia are not getting all hyped up and people often times are trying to get out from there even that it is almost not possible - see i.e. Norilsk

Mars with its -80 degC is much harsher desert than dirty industrial towns of Siberia.

I mean... Not that many.

I've watched a few documentaries and there are barely a handful of houses let's say in Death Valley. And Death Valley is a lot more hospitable than Mars.

To each their own, though, sure!

"Eventually" might be several million years though, and a lot of death in between.

In evolutionary theory is there a term for plateaus of differentiation?

Do you mean "punctuated equilibrium"?
WOW, COOL. Thank you!! Yes. Informative.
the only realistic chance is to find a mega iceteroid than just happens to only need a nudge to get it to crash into mars, preferably going realy real fast and into one of the poles, that then releaes enough water and heat to react most of the nasty stuff and increase the atmospheric pressure. ion engine space tugs, huge ones, and for that matter, crash anything that is possible into the poles. Pro tip, aim for the fourth planet out, #4, red one, you dont want this happening to the planet you are standing on.
Fascinating. I first heard of this terraform idea a few years ago. Question - how do we get the ice to melt enough to have something similar to oceans?
IIRC solar mirrors in orbit & artificial green house gases are often mentioned.
I do wish Elon would focus more on getting to Mars.
I think it's already save enough. He should take the risk to be the first person.
There is basically zero chance of that happening.

Not that this is impossible to do, but under Elons leadership it will never happen. Intelligence is non separable, you can't be smart in one area and be idiotic in another - if you are good at logical thinking, truth seeking, and problem solving this applies to everything you do in life.

And its pretty evident with Starship it has been a collosal failure so far. They have just barely gotten it to the same functionality as the Falcon, with engines that are equivalent of putting a turbo+nitrous system on a base spec Toyota Corolla. They still have to figure out not only staying in orbit without issues to refuel, but also multiple restart attempts.

With finances, it has been shown that Falcon launches are heavily subsidized, which is why they are cheap, and in reality, there is a lot of money spent fixing the vehicles for next launhch. Space X has no experience in multiple launches of the same vehicle without work. On Mars, you are not going to have a full factory with full engineering staff to basically fix up the Starship for next takeoff.

All of this is compounded by the talent pool of people still willing to work for Elon, with ever sinking stock price. There is enough inertia there to keep the Falcon program going, but the mindset of everyone involved in Starship is by far not conducive to make Mars happen.

> Intelligence is non separable, you can't be smart in one area and be idiotic in another

This is patently false.

> if you are good at logical thinking, truth seeking, and problem solving this applies to everything you do in life.

That's how we STEM people like to see ourselves, yes. But that's rarely how it plays out. First, ego gets in the way. When someone thinks they understand something (even if it's way outside their field of expertise), they are much less likely to do the truth seeking part. So they stick to erroneous beliefs which results in them making idiotic claims.

Then you have the fact that STEM people struggle with nuance. They prefer cold simple logic. Which results in views on nuanced topics such as human behavior that are so appalling it's become a meme at this point.

Then you have the classic counter example of geniuses going off the deep end with the Nobel disease.

Lol think about what you are saying. You are basically demonstrating the non-intelligent people.

If someone ego gets in the way of understanding something, or they don't pay attention to counter evidence to what they believe in, that is an inherent process that does not represent truth seeking, therefore they are not intelligent.

I think you are confusing intelligence with ability to recall stuff. Memorizing stuff isn't intelligence. We have LLMs for that now. Intelligence is the ability to accurately simulate reality with a high degree of accuracy in your head, which includes understanding where the gaps in knowledge are. Anything other then that is not intelligence.

And this is something so fundamental that it can't be taught. You are either born with ability to prioritize that over empotions, or you aren't.

> Intelligence is the ability to accurately simulate reality with a high degree of accuracy in your head

Mathematicians (eg: those that first conceived of non Euclidean geometries) aren't intelligent in your opinion?

Everything an intelligent person thinks must conform to some common hallucination or perception called "reality"?

Wowsers.