Comment by teachrdan | Hacker News Reader

Comment by teachrdan | Hacker News Reader

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I've got to strongly disagree with Mars being "level 2" anything. Just the 6-9 month trip to Mars would expose humans to a lifetime of radiation; a "standard" mission to Mars -- voyage plus 1.5 years on-planet and back -- would expose astronauts to a total of hundreds of years radiation. When calculating total exposure per astronaut, you'd obviously have to include their (normal) exposure on Earth as well. Not great!

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!

Your numbers are quite off. The ambient radiation level on Mars is less than what astronauts on the ISS experience. And that's direct exposure. We've had numerous astronauts spend years in space in total. That'd be the equivalent of sunbathing on Mars, which is obviously not exactly the plan there. And so far whatever effect the increased radiation has had is small enough that it's not statistically detectable.

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.

> The ambient radiation level on Mars is less than what astronauts on the ISS experience.

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

Your link is about radiation in space around Mars, not on the surface. That's why they pointed a spectrometer at the sky, and the final section you quoted speculates about surface level radiation rather than providing it. Here [1] is a study on the surface level. It ended up a bit below the ISS. And radiation exposure is cumulative. You don't just reset after leaving the radiated area, so what matters is the total time in space, not the longest continuous stay. The longest continuous stay(s) were intended to deal with another issue, actually related to Mars. Obviously your muscles/bones/etc weaken greatly in 0g. And so the practical concern was would people be able to get to Mars and actually start working hard on the surface after a spending months in 0g space.

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

> Your link is about radiation in space around Mars, not on the surface.

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.

-- This post ended up longer than expected. I'm not trying to respond to you with a wall of text, but I also don't want to be flippant with my responses. So I apologize for the length.

Let me start with the last thing you said. Is 'the idea is cool' a valid reason to go to Mars? First I think achieving great things is good for humanity - period, but there's even a purely pragmatic motivation as well. After we landed on the Moon the number of people wanting to (and who would) go into sciences, become astronauts, and other such things skyrocketed. The exact same thing is happening in China today where the majority of kids want to become astronauts or teachers. Whereas in America and the UK the plurality want to become streamers, with seemingly the majority having no direction for their life whatsoever. [1] Which next generation do you think will 'win' the 21st century? Even outside of competitive aspects, which generation is going to create a better country?

As for the radiation, you're again primarily referring to space radiation. Table 2 on the study shows their measured Martian surface level radiation level, which is less than the ISS. The space radiation is something that needs to be dealt with. Fortunately the current estimated trip length is 50% of their estimates - around 3 months, space weather events can be more effectively shielded against, and so forth.

And filtering out perchlorates isn't some advanced industrial process. It's literally just filtering water in a normal way. Plain old cartridges (specialized for perchlorates) like you might use in an at-home filter would work just fine. The reason I mentioned astronauts being enthusiastic about going to Mars because you have the most qualified people on Earth enthusiastic about it, some of the richest people on Earth enthusiastic about it, and billions of others. So it's obviously going to happen. There's no coercion or sacrificing people or whatever. It's a free world, and hopefully in the future we can make worlds plural.

---

Robots are an interesting topic because people don't seem to understand how limited they are, though it's self evident if you think a bit more deeply about it. The most fundamental problem (among many) is that moving parts break. So for instance Curiosity's drill, as underpowered as it is (able to dig a narrow hole to about 6cm) broke after about a dozen light activations. It took a team of scientists almost 2 years to come up with a work-around that still left it crippled, but at least kind of workable.

And the drill is just one aspect. The more obvious one is moving. You have to be extremely cautious when doing such meaning major human oversight, and with an average round-trip latency to Mars of around 25 minutes, well - you don't move much. On average Curiosity travels about 1 mile per year. Try to imagine digging into the secrets of Earth by using a drill you can use a few times for holes up to 6cm deep, while traveling at mile per year. We're not even scratching the surface of Mars, quite literally.

And this is isn't just a technological problem that can be hand-waved away, because the reason things are in this state is because moving parts break. A human on site could have likely easily fixed the rover's drill in about 30 seconds, or just did a way better job of 'drilling' with a spoon. Humans will discover more about Mars in a week or two than the past 60 years of probes and rovers have, and likely even more than another century of such would achieve.

[1] - https://www.statista.com/chart/28802/childhood-aspirations-i...

> Robots are an interesting topic because people don't seem to understand how limited they are

You've hit the nail on the head here. Investing in robots is an infinitely smarter -- and more cost-effective -- play than just sending humans to Mars and hoping for the best, centuries worth of radiation be damned.

If robots really are too fragile to do so much as dig holes in the Martian surface, then lets improve the robots. This has the added benefit of having actual, immediate utility here on Earth!

You're saying that robots are too fragile to rely on for Mars exploration. You know what else is fragile? A human being. And it's far easier to make a robot more durable.

This conversation has helped me understand what I personally believe to be a fallacy behind almost all arguments for the human exploration (much less settlement) of Mars: the fallacy of urgency. There is absolutely no reason why we must drastically increase our exploration of the surface of Mars right now. (or in 10+ years or whenever we would hypothetically land humans there)

If it takes longer than those "10 years" to design more competent and durable robots, who cares? There's exactly zero rush to send humans to Mars -- except that, you know, it would be kinda cool if we did. The money spent on robot research would more than pay for itself in utility on Earth in a way that money spent on shielding humans and sending the cargo necessary to keep them alive in a distant, hostile environment never will.

I think you are rather dramatically underestimating what goes into the current systems of robotics. Curiosity and Perseverance are the result of decades of research by teams of hundreds of scientists with decades of work and research and budgets in the billions of dollars. 'We just need to make them orders of magnitude better' is nonsensical. You're looking at the best that we can do, and it's nowhere even remotely near to what's needed for robotics to be effective. And fragility is just one aspect - mobility, power, and many others also lag far behind what they'd need for robotics to be viably competitive with humans.

So now you're left with some argument that ends up like 'Okay - so we can't do it with robotics right now, but I want to do it with robotics, so we shouldn't do it until we can do it with robotics.' I mean the answer is quite obvious. Humans can do it, humans want to do it, and thus humans will do it. I don't entirely understand why you're so averse to this. To not be coy, one obvious explanation is a political thing about Musk. Outside of that being petty, it's also largely irrelevant - China's a major player in this game as well, and it's conceivable that they get there before we do. And I don't think this is just going to be a two pony race this time either, especially when the goal isn't just footprints and flags.

My objections have nothing to do with Musk; they would be exactly the same in substance and intensity no matter who the US government was paying to do it.

My objection is that this is a pointless waste of hundreds of billions of dollars of capital, money that can and should be used for more useful pursuits, including those which will make Mars research more cost-effective in the future.

Humans going to Mars would be limited to staying in a tiny portion of the planet; robots could be deployed anywhere. Humans have to be protected from all threats, including, yes, centuries worth of radiation, getting poisoned by perchlorates, and committing suicide -- as well as the same Mars particulate matter that threatens the current generation of robotics.

We would be foolish not to spend the money that would go into sending literally hundreds of tons of life support to Mars into robotics and adjacent technology instead.

Because, who gives a shit if China gets there first? Having more effective robots capable of more human tasks in more (and more hostile) environments is far more worthwhile than racing another country in what amounts to an international dick measuring contest.

Yes, let's explore Mars. Let's explore more of it with robots, far more, and more thoroughly, than we could conceivably do with humans, and for a fraction of the cost.

One thing our conversation demonstrates is that what's useful to one person is quite useless to another. I think the main reason that historically free countries have advanced far more rapidly than those with controlled economies is precisely because nobody has a broad enough, let alone objective enough, perspective to appreciate everything of value.

So what does the future of space hold? A fun thought experiment is to go back to 1969 after we landed on the Moon. At that point NASA already had big plans for getting to Mars, and they were viable. But Nixon chose to defacto cancel the human space program in 1972. He felt that a catastrophe was inevitable and that it'd harm his political ambitions. But what would have happened if we had carried on with NASA's plans?

Surely you'll agree that it's, at the minimum, viable that we'd have succeeded there. And that would entail the construction of substantial interplanetary logistics, outposts, and more. To say nothing of the endless discoveries and 'unknown unknowns' that we would have made along the way. The potential opportunity and advances there are difficult to overstate. And this would have been quite a modest prediction of the future if you asked somebody in 1969 what 50 years later would hold. After all we had just gone from 'nothing' to man on the Moon in 7 years.

Instead, we turned to robotics. And what do we get after 60 years? We finally learned that Mars surface regolith has significant quantities of water. Yay? On top of the severely crippled progress, there's also the human loss. Right now NASA's Artemis Program is basically just trying to recreate 1969, and doing a poor job of it. Decades of skill/labor atrophy mean we're left trying to 'relearn' what we knew in the 60s, but doing so in an environment where everything costs much more, moves much more slowly, and where human talent is focused in fields like ads and finance, instead of anything of value (well I suppose LLMs are changing that, but that's another topic).

Basically space is a frontier that opens the door to practically infinite resources, land, and even knowledge. If post scarcity is possible, the only way there is through space. And the only way we're really going to advance along that frontier is with humans.

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