points by Levitating 4 days ago | 0 comments
The cosmic radiation alone poses a major problem, let alone the logistics of supplying water/air/food. I am much more optimistic for a research outpost on Luna.
Though the person you commented on didn't refer to habitation specifically I think, just humans on the surface.
[–] King-Aaron 4 days ago
[–] somenameforme 4 days ago
Since Mars atmosphere is 95% CO2 you're pretty much good to go there with a moderate supply of hydrogen. And conveniently enough electrolysis of water yields of course hydrogen and oxygen. And water is shockingly widely available on Mars given the regolith is 2-5% water by volume (giving the unit bastardization of 1 cubic foot of regolith = 1+ liter of water).
Most of the issues people are concerned about like radiation aren't, in reality, that big a deal. I say 'in reality' to mean that the radiation isn't enough to just give you immediate radiation sickness, so the real effect will be a probably reduced life expectancy due to greater rates of cancer. Even that isn't so clear for reason outside the scope of this post, but it's not a show stopper in any case. In general early colonists will have a significantly reduced life expectancy - it's just the nature of colonization, and always has been.
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Beyond that the Moon is a nightmare. Relatively minimal resources, 2 week long days/nights that vary between way beyond boiling hot and something close to absolute zero. No atmosphere at all so no protection against meteorites, somewhat higher radiation than Mars, and so on. There's also gravity very near zero which can pose some issues with various processes (industrial/etc).
And other destinations like Europa not only have dramatically more difficult 'local settings', but also have significantly greater distances. For instance Europa is about 10x as far as Mars and a somewhat more difficult trajectory to manage. In practice you're probably looking at upwards of 5 years for a one-way trip. We probably need to level up the tech tree a few bumps before realistically looking at things like that and Mars is a good way to do that.
[1] - https://en.wikipedia.org/wiki/Sabatier_reaction
[–] teachrdan 4 days ago
Having said that, there would also be the cumulative effects of low/no gravity on astronauts. Even a year on the ISS has profound negative effects on the human body. And humans have cumulatively spent less than a month total on the moon. We have no idea how astronauts would fare on Mars for 18 months, but it would likely be very bad. And then they'd have to successfully get home.
You also have abundant toxic chemicals in the Mars regolith. Whatever technology we'd use to extract drinking water from it would have to filter out perchlorates, which are extremely toxic to both mammal and plant life. AFAIK we've never done this at all on Mars, and now we're talking about having to do it successfully for 18 months (even with water recycling). Not easy!
To be fair, a lot of proponents of human Mars exploration -- particularly here on HN -- see astronauts as essentially disposable. "Who cares if they risk dying of cancer / poisoning / suicide? It's worth it!" But if you prioritize astronauts surviving both the mission to Mars and the return home there are many, many, many unanswered questions, questions which may indeed have no good answers at all.
Before you accuse me of being a hater: I fully support exploration of Mars, and the rest of the solar system. And the best way to do so, by cost and every other conceivable metric, is with robots. Lets spend way more on space exploration, do it with probes of all varieties, and learn more in our lifetime than in all previous human lifetimes put together!
[–] somenameforme 3 days ago
Some misleading articles (or one heinous book) try to count in-transit space weather events as part of the average to bring the numbers to the point of absurdity, but that's plainly lying. Space weather events (like solar flares) are immediately lethal if not shielded against. Fortunately they're easy to shield against since they're predictable and all settlement ships will happen to have one of the best possible radiation shields in large quantities on board - water. Similarly for perchlorates. These can be filtered out with basic water purification tech and trace amounts are even present in much of what we consume on Earth, especially in certain areas.
I'm not accusing you of being a hater, which is quite pointless. But I would say you've probably been misinformed. And I suspect precisely by one book written by a comic book artist. Somebody should probably just make a site 'clarifying' it page by page because it's chock full of misinformation and certainly a contender for the single worst pop-sci book published in modern times. It's the analog of people thinking the Moon landing was a hoax because they read some misleading article about the Van Allen Belts, all of which tend to like suggesting you'd need a radiation shield which would probably have gotten the astronauts killed due to bremsstrahlung, but I digress.
[–] teachrdan 3 days ago
False, at least according to Wikipedia:
"JPL reported that MARIE-measured radiation levels were two to three times greater than that at the International Space Station (which is 100–200 mSv/a).[3] The levels at the Martian surface might be closer to the level at the ISS due to atmospheric shielding – ignoring the effect of thermal neutrons induced by GCR."
So a "typical" 18-22 month mission on Mars will still add up to 60 to 92 YEARS of radiation exposure on Earth -- assuming 100% perfect shielding to and from Mars, which seems exceedingly unlikely.
The longest stay aboard the ISS was 437 days. The round trip to Mars alone would be between 360 and 540 days. Between the trip and the stay, astronauts will be exposed to conditions that, to the extent that they have been explored, are incredibly harmful to the human body: low/no gravity, elevated levels of CO2, etc. And they'll spend the bulk of that time on a planet that is months, at best, away from any support on Earth.
They're also going to be exhausted due to the rigors and harsh environment of space, while also bored due to the absence of anything to do for fun besides consuming media; after all, there'll be no humans to talk to synchronously besides the same, small number of fellow crew members. (It's my pet theory that they'll all have LLMs and get way deep into AI psychosis.)
If you see the lives of astronauts as being essentially disposable, then these are not concerns of yours. But when you consider that sending humans to Mars to do research is the least cost effective approach imaginable, even a bit of concern for their safety should give you pause.
https://en.wikipedia.org/wiki/Mars_Radiation_Environment_Exp...
https://www.sidc.be/article/radiation-space
[–] somenameforme 2 days ago
So that's where out friend Valeri Polyakov [2] comes in. His first words after landing following his initial 240 day stay in space were "We can fly to Mars." He then made an even stronger point of it by spending more than a year (continuously) in space, landing, and then immediately briefly walking after landing on Earth. As Mars is around 0.4g and the trip there wouldn't take anywhere near a year, it was a pretty clear demo that we can definitely get to and start working on Mars. Also, he spent another even longer stay in space later on. And would go on to die aged 80.
As for your concern about astronauts being bored. Well, let's just say I think they'll find a few ways to keep themselves busy - turns out there's quite a lot to do when starting a civilization. And disposable stuff is a bit off the mark. Nobody's sending anybody to do anything - everything is about personal choice. Would you rather have a life expectancy of let's say 10% less than average but filled with a life lived to the absolute extreme, or a life expectancy of let's say 10% longer than average, but where somebody lives in a bubble and avoids doing basically anything just to try to eek out a few more years? I think almost everybody would pick the former option. A good chunk of astronauts come from backgrounds like military test pilot, which means you certainly already know their answer.
[1] - https://www.scienceintheclassroom.org/research-papers/curios...
[2] - https://en.wikipedia.org/wiki/Valeri_Polyakov
[–] teachrdan 1 day ago
Your own source disagrees with you. According to the paper, you cited:
"Combining our measurements with those obtained during the cruise phase (22), we estimate a total mission dose equivalent of ~1.01 Sv for a round trip Mars surface mission with 180 days (each way) cruise, and 500 days on the martian surface for this current solar cycle (Table 2)."
As a reminder, 1.01 Sv is about 275 YEARS of radiation. Not good!
And the fact that a single astronaut is bullish about astronaut stuff should not determine out space exploration policy. Who cares if he wants to go back to space again?
> Well, let's just say I think they'll find a few ways to keep themselves busy - turns out there's quite a lot to do when starting a civilization.
There's no doubt our hypothetical Mars explorers (settlers, now?) will be busy. There will be tons of measurements to take, repairs to make, construction, maintenance, etc. But it will doubtless be tedious to be so far from the slightest bit of nature as we know it on Earth, or synchronous communication with anyone but each other, stuck in low gravity and inside the same small habitats (or space suits). And that will be their reward after 180 days of space travel!
I did some light research into the perchlorate-in-water issue, and you're correct that there exist industrial processes on Earth to filter them out. But at this point we're not just shipping pilots and engineers and scientists to Mars, but also perchlorate removal specialists to operate these machines.
What's the point? If it's to explore Mars, then we're wasting untold hundreds of billions of dollars to send humans to do a job infinitely better suited to robots. If it's to explore Mars (2), then why are we setting up industrial machines to extract water from its surface and do permanent harm to the place we're supposedly interesting in learning about?
The only credible answer left is, "We should explore Mars because the idea is cool." That's fine if Elon Musk wants to pay for it. But that money is infinitely better spent on Earth -- even if, or especially if, we invest it in building robots to do that exploration for us.