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points by NitpickLawyer 4 days ago | 0 comments

I really hope we'll see humans on Mars in my lifetime. For all the amazing success that rovers had, starting with Spirit and Opportunity, and now with Curiosity and Perseverence, having a bloke with a shovel can likely be more productive in a few days than years of missions combined...

[–] King-Aaron 4 days ago

The recent findings about the dust being so fine it can penetrate the blood-brain barrier is a real concern though. The more we learn about the planet, the more it sounds pretty unsuitable for habitation.

[–] Levitating 4 days ago

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

I tend to agree with your thoughts on the moon. Realistically we should be looking at orbital manufacturing and refuelling in our local neighbourhood first and use Luna as a staging area for any deeper missions, of which I feel there's far more interesting features to look at (i.e. Titan, Europa etc)

[–] somenameforme 4 days ago

I don't really think so. To start with there's a lot of really interesting concepts in terms of habitation for Mars. For instance the water/air stuff is oddly enough solved simultaneously, alongside fuel. The Sabatier Reaction [1] and various other characteristics of Mars really make it all feel like a video game where Mars is just clearly level 2. The reaction itself is CO2 + hydrogen = methane + water.

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

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!

[–] somenameforme 3 days ago

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.

[–] teachrdan 3 days ago

> 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

[–] BurningFrog 4 days ago

Pretty sure the plan is to use space suits for outdoor work.

[–] tokai 4 days ago

If you ever bring any suits or equipment inside, you have the dust inside. No matter the cleaning you do first.

[–] King-Aaron 3 days ago

I believe they were finding it can cling to the suits, and have the potential of getting into a habitat

https://www.pnas.org/doi/10.1073/pnas.2620747123

[–] Tangurena2 4 days ago

Hope is not a strategy.

Our existing method of moving between planets (heck, even the Earth & Moon) will take 9 months to get from Earth to Mars (or back). And the launch window is every 22 months. The return to Earth is either 4 weeks after you get to Mars, or 23 months later (so any fault that prevents a prompt return means you better have almost 3 years of food/water/air onboard).

Without some magical SF technology being invented, no, we're not going to see humans travelling to Mars in our lifetimes.

If folks are serious about human trips to Mars, there would be an effort to send supply ships ahead of time and stockpiling fuel/food/water/air in orbit around Mars. This would solve 2½ problems:

1 - Carrying supplies for both directions would require building spaceships bigger than we can currently build.

2 - If there is any failure on the way or at Mars, there will be stuff to let the astronauts survive until they can fix things or any sort of rescue mission could be sent.

And "that half" - Currently, the US has had a 70% success rate sending stuff to Mars (the Soviets had 50% success). Some of those supply ships won't reach Mars orbit. Some will break on the way there and drift past Mars. Some will smash into the surface of Mars.

Why send stuff? Supplying the astronauts on ISS requires sending 1000 pounds of stuff per person per month. And that's only 300 miles from Earth. And the ISS has water recycling, yet they still need water sent up.

My estimates for a successful "manned" trip to Mars (and return them safely to Earth again) would start around $200 billion.

https://en.wikipedia.org/wiki/Hohmann_transfer_orbit

https://en.wikipedia.org/wiki/Launch_window

This page claims Earth/Mars launch windows are every 26 months:

https://en.wikipedia.org/wiki/Exploration_of_Mars#Launch_win...

[–] BurningFrog 2 days ago

I think Elon has said these costs in a main reason he's accumulating so much wealth.

[–] fma 4 days ago

Google says the Iraq war cost $2 trillion, give or take a couple hundred billion.

So you are telling me we could have gone to Mars and back a few times instead..

[–] Tangurena2 4 days ago

If you count the massive increase in 3-letter-agency budgets along with the costs/effects of PATRIOT ACT type laws, then I think google's estimate is probably an order of magnitude low. Yes, the wars in Iraq & Afghanistan were running about $1B per day for 20 years. We could have had UBI, universal healthcare, ended homelessness as well as going to/from Mars several times for the amount wasted on Bush's wars. And we're starting a war with a country 4x bigger, 2x more population and unlike Iraq, occupies 3 dimensions while alienating every ally we had for the Iraq/Afghanistan war.

[–] podocarp 4 days ago

Bringing our woes to other planets too…

[–] solyin 4 days ago

Would a remote controlled humanoid robot from an orbiting platform be a possible compromise?

[–] NitpickLawyer 4 days ago

I doubt it. Going to Mars just to enter orbit would probably require the same (or more) delta v as landing (because of aerobraking). And then you'd still have to resupply them, and that will certainly be more expensive. Your resupply missions now have to achieve orbit, and dock. You can get much cheaper "dumb" cargo to Mars by using "old" tech developed for the first rovers (parachutes + airbags).

And even then, again there's just something about a trained geologist being there, immersed in the thing, thinking on the spot, using a shovel that just can't be matched with robots.

Then you have all the ISRU (in situ resource utilisation) that you can take advantage of on Mars vs. in orbit around Mars. There have been experiments already demonstrating obtaining useful stuff (MOXIE got oxygen). And theoretically you can also make methane, you can melt water, etc.