> In an open system, an effectively infinite supply of natural raw materials can be used, and wasted, as needed. The Mars city solves this problem by building on the surface of a planet that is made of all the raw materials it could need.
It makes me sad to think that exploration and settlement of the solar system would take with it this kind of thinking, which is dangerously close to rendering the Earth uninhabitable.
The Earth (and Mars...) are, in some sense, closed systems, in that exploitation of resources has a hard limit beyond which we're looking at biosphere collapse, or just plain resource exhaustion.
Maybe we could use space exploration to come up with a different way, and then roll that back into how we live here on Earth.
Idk... To me, terms like "exploitation of resources" tend to be overloaded with connotations to "think past" concretely.
People have a big impact on our environment, and the definition of "environment" keeps ratcheting up with the scale of humanity... As the number of people, the scale of our impact, and our knowledge of this impact our definition of "our environment" expands.
That's not likely to change. We're not going back to our environmental niches and we're not going to be a impact-neutral observer of "the natural environment" either. We're going to maintain our place between gods and beasts, so to speak.
That doesn't mean we don't/won't evolve. There is definitely no sense and future in bluntly walking in to environmental hard-limits like climate change, biodiversity crisis or any other pressing catastrophe.
But.. perfecting ourselves to the point where we've "moved beyond" resource use shaped by our wants and needs, exploitation...
In any case, I think the environmental ethos of the future can be left to future people. It will inevitably be shaped our ours' mistakes, and their consequences.
I think a lot of those concerns disappear once you leave Earth. What makes our planet precious is how uncommon it is. The universe is incredibly vast, yet we have not observed life on any planet but our own. So to me whatever the cost is to a planet like Mars of putting life on its surface, that cost is well worth it (the planet certainly doesn’t mind). The only ones who might be offended by this idea are us Terrans.
> It turns out that the main advantage of domes – no internal supports – becomes a major liability on Mars. While rigid geodesic domes on Earth are compressive structures, on Mars, a pressurized dome actually supports its own weight and then some. As a result, the structure is under tension and the dome is attempting to tear itself out of the ground. Since lifting force scales with area, while anchoring force scales with circumference, domes on Mars can’t be much wider than about 150 feet, and even then would require extensive foundation engineering.
Does it need to be more extensive than "make the very bottom ridge of the dome wider than the dome itself (some kind of "lip") and place it into the groove carved in the rock?
Yes... Remember that there's 1 bar of atmosphere in there. 150 feet (45m) makes for a circle of 140m circumference but 1600m^2 area. Since 1 bar ~= 100_000Pa, each of that square meters has 100KN of upwards force on it, for a sum of 160MN distributed over 140m of circumference or ~1MN per meter. So assuming the mass of the dome is negligible, we're talking about the equivalent strength of holding on to a mass of about 100 metric tons (compared to Earth gravity) per meter of dome. Ie. the amount of support you need per meter is the amount that you would need on Earth to hold up 100 metric tons against gravity. That's about a Boeing 737. Per meter.
Steel cable with a diameter of 1inch has a breaking strength of 47 tonnes. Give it a safety margin and assume it can hold 10 tonnes. So you need 10 cables per meter. So I assume in case the "lip" being just a sheet of steel it can be way thinner than 25mm.
Sure but you need to be sure that the thing you're attaching it to can hold the weight. Ie. if the martian floor was the ceiling, you'd have to be able to hang a plane off that attachment point without it ripping out.
In other words, your lip needs to be distributing force onto a sufficient volume of ground to make up 100_000 metric tons of martian soil, per meter of circumference.
That's why the author suggests peridiodic anchors, like an air mattress. As other commenters have pointed out, you don't want the structure to deflate in the event of decomp, so a strut which is useful secondarily in compression is useful here.
Basal fiber is about 3GPa tensile, call it a MoS of 6 for a neat 500MPa working strength.
If you plug int wolfram alpha `1 atmosphere * 1 square meter / 500 MPa` you get 2 cm^2 of support (tethering) per sq m of roof. That's reasonable.
But here's the rub: compressive strength lags tensile strength. Even granite is a mere 130 MPa. So even a strut which has some compression resiliance is not gonna be enough to fully abate a collapse. So it's very likely a Martian structure would have some arc to it, as it both benefits tension under nominal operation and some compression in failure mode, at least long enough to keep pressure from dropping too low.
I imagine rip-stop at all sorts of scales will be implemented. It's not gonna be like an inflatable golf dome.
The solution here seems fairly straightforward: don't make the design completely pressure-supported, but include enough weighty structural elements like ribs and beams to make it heavy enough to be a compressive structure again. If you have a rib-like structure on the top side of your dome material, you could even just pile Mars dust and rocks on top of it to keep it in place.
sand/dust blows around into dunes and its dense enough that "close enough" won't hack it. Figure as an engineering 1 sig fig estimate (dry) sand runs around a twentieth of a pound per cubic inch, so 14.7 PSI air would be in compression with around three hundred or so inches of sand evenly spread around the top.
Its a major labor sink to build and maintain and dunes could cause a catastrophic failure. Could make an interesting sci fi novel about "emergency EVA to run bulldozer drones to spread sand to prevent dome collapse".
In the end, rather than the nightmare of making a 3000 meter diameter dome deep enough under ground that dune forces will have no effect (using h-bombs to excavate?), just make thirty 10 meter diameter tunnel boring machines and run them 10 kilometers in different directions.
The linked article's tube tent is not a bad idea for surface greenhouses.
What happens when the tent loses pressure? Wouldn't you then need fallback supports with compressive strength? Although assuming the force exerted by pressure is at least twice that of gravity (so that pressure minus gravity is still greater than gravity by itself) the requirements for the fallback supports probably don't have to hold as much load.
The whole thing would collapse. However, given a big enough scale, it would take a long time even if there was what we would think is a big hole in it. But even then, they'd have to have a number of contingency plans; a supply of compressed air that can be manually released in case of a power outage for example.
I believe this post ignores the implications of increased surface level radiation (Mars does not have a protective magnetosphere). See the two articles I link below.
A structure like this might make sense for a shorter mission - but considering the thought experiment asks what structure would be suitable for a long term Musk-style settlement I don't think thin ETFE would be enough.
At least part of the radiation risk is temporary solar events, so perhaps you could use a slightly hardened version of ETFE as the author suggests but keep all human activity near regularly placed deep shelters to retreat to when radiation spikes are detected?
I think the implication is that under this tented tensile structure you could build whatever radiation shielded (or not) structures you wanted, and this just contains the air.
Radioactive particles (dust) in air are problematic. The gas in air does not become radioactive (at least in a dangerous way) from exposure to radiation.
If the surface of mars is exposed to radiation capable of making particles become radioactive, does that mean the surface is already radioactive? Or would this only happen to airborne dust particles, not to sand particles on the ground?
If you're breathing silica dust you're going to get silicosis anyway, so there's not much point worrying about it.
Maybe the living area buildings inside the tent can have a vestible / "dustlock" for keeping the dust outside, and outside those it just becomes standard to wear a dust mask.
If you’re putting all of your eggs in the “shielded other structures” - why have the other structure in the first place? It’s not as if you can live outside those “other structures” if you’ll just die of radiation poisoning.
Or, to put it another way, any structure capable of shielding against cosmic radiation should be capable of also holding air (we’ve gotten really good at that).
The article's author points out that normal radiation on Mars is about the same as background radiation in Ramsar, Iran. Residents there have normal lifespans and cancer rates. Solar storms are a problem but fortunately, they give you enough warning to take shelter.
Thanks for this interesting link - I take back my criticism of the article! Based on your comment and that of t3hz0r it sounds like the martian colonists would be fine with this setup, as long as they mainly worked and lived in shielded habitats within the ETFE covered areas and also had underground shelters for emergency radiation protection.
I'll just point out that a Boring Co machine will fit inside a Starship.
Underground may be the only way to live, given that radiation dosage is cumulative, 24/7, it may not be possible to live on the surface at all in inflated domes. Maybe they're better suited for equipment storage and agriculture.
The biggest problem of these artificial environments is the threat of sabotage from either disgruntled, suicidal or criminal minds.
You can vet people as much as you want but with the pop they are talking about someone’s bound to go crazy or be an agent of discontent. And then if they are settlers of course their children can be as varied as they are on Earth, which means the possibility of the same.
I don't see where criminal fits in aside from the fact that a sabotage of that sort would rightfully be hideously illegal. What is to gain personally from that destruction?
It might be a pedantic quibble but I can see power as the only "rational" sabotage motive. Which could include some disgruntlement. Either to oust management or rivals to gain control or possibly international politics where one thinks they can gain from the loss of the colony for the sake of their earth nation.
Suicidal can be taken as granted to be irrational and disgruntled relatedly as "so fed up they want to see everything collapse to make them suffer".
Imagine beeing sentenced to a desert prison, by your parents, a monastry of eternal work and little fun, where all the beauty of world, is that coming from another world, as videos, games and mail, which you can never reach.
Maybe a part of the mission is to design a society to minimize or eliminate violence, mental illness, crime, etc. What would a society look like that depends on near-perfect harmony and peace for its very survival?
I would argue that it would be a dead society. It just takes one person who feels that being hurt themselves is worth it just to hurt others for whatever reason.
I thought going underground was the way to go. I wasn't imagining a "pressurized tunnel" but rather a pressurized underground complex filled with tunnels and rooms (minecraft).
But maybe pressurizing an underground complex with walls made out of ...Mars is more difficult than building something on the surface?
Going underground seemed like it had limitless room for easy expansion.
I like the authors suggestion and it does sound better than a dome but living underground seems safer to me.
Yes, it is curious that natural land features are not exploited more. You can put that city wherever you want on Mars.
Cover a canyon (walls for free). Use lava tubes. Or search for any peculiar geological feature that is amendable. I don't get why the assumption is a completely flat, desert surface.
On the other hand, cities on Earth are very often bounded by other natural features like rivers and mountains that naturally constrain easily-usable space. On Mars it would seem to me the solution to needing more space would be the same as on Earth - build another city.
Maybe. But if you have a canyon, you can use three natural sides, cover the top and one side. The side you can expand as needed.
Cities on Earth don't need to be protected from toxic soil and hard UV radiation. Instead, most cities on earth have been built near rivers for cheap transportation. Castles and fortifications are built on hills for defensive value.
This is partially due to (current) landing site requirements. Up till now landers targeting mars could not really handle any bigger terrain obstacles (big rocks, steep slopes, etc.) so the landing sites have been meticulously selected to be as flat and rock free as possible.
That's why photos from different Mars landers look often very similar - the regions they have landed in have been effectively selected to be similar. :) And of course these pictures shape how Martian surface looks like the public consciousness.
Things may be changing though, with the technology being developed for active obstacle avoidance, that might enable martian landers to land in a more complex terrain safely by analyzing the actual landing site and landing on a safe spot.
Still, you might still want some flat area near an early martian base/city, even just to make trucking stuff from/to landers that strayed of course during landing easier. Eq. not having one in the middle of a rock field and another on crater bottom. :)
I’d imagine building out some new support pillars and flexible ceiling would be much faster and cheaper than digging out the same space underground.
I know tunnel boring is supposed to be getting cheaper and easier, plus on Mars you’d be starting from a blank slate rather than working around/under existing infrastructure. But for big tunnels you still need a big boring machine, and that would either have to be shipped to Mars or built on Mars.
I'd think an inflatable habitat inside a lava tube would be ideal. For the Moon, it'd be perfect - lava tubes are supposed to have lots of ice in them.
There are photos of lava tubes that are hundreds of meters wide and kilometres long. That's a lot of space shielded from radiation.
I personally suspect the main reason for going above ground is morale and psychological essentially to have some sunlight and a view of the world they are settling to validate the purpose on an emotional level.
I am uncertain of the ergonomics of living spaces in artifical environments - I suspect even the experts are uncertain and even if they invested heavily they would discover design mistakes to correct in future iterations.
The way I would do it is send a lot of self replicating terraforming robots. That requires relatively little cargo - the only components that cannot be manifactured on mars directly are smd and processors.
Not that I believe we are anywhere close, but processors could be made on the moon. Maybe not modern ones, but working ones. Also if space is not a problem, quite large ones too.
I have a Nobel prize and a billion dollars of VC money right here in my back pocket. All you've got to do is demonstrate your design for a self replicating general purpose constructor robot. Actually anybody's demonstrable design will do, and I'll give you a sweet cut of the VC money.
As reductive as "just send self-replicating robots" is, it's still potentially easier than a self-sustaining human civilization like the article is talking about. Both require building the entire set of infrastructure to build industrial infrastructure and computers. The robot approach requires that every single factory and excavator is automated* - a huge feat. The human approach requires every piece of infrastructure the robot one does, plus the infrastructure to make pressurized domes, oxygen, food, heating, etc, etc, and also requires shipping large numbers of humans through the vacuum of space - also a huge feat. I don't think it's a given that either approach is easier.
* At least, automated enough that it's not bottlenecked by humans operating robot arms at a 30 minute feedback delay.
Aside from we don't know even in theory how to do it, which is a bit of an obstacle to overcome, I don't see how this could work without developing AGI first to operate it. That's probably at least a couple of trillion worth of R&D right there, and then again we don't actually know how to start on that even in theory.
In total the US already spends half a trillion on R&D per year. The US military spends a trillion on R&D every 15 years and the IT industry does about the same, and bear in mind most of the research these organisations are already doing would be directly relevant to a project like this. So in a way we're already doing it, and I don't see any from-scratch full-civilization self replicating technology architectures coming along on the horizon even as a theoretical exercise. Even for something like interstellar probes at least we have outline designs.
Release a bunch of balloons into the air. They'd float to the leak.
If you want to get fancy, coat them with a glue that bonds to the ceiling material, and they'd fix the leak too! At least temporarily. My first thought was that they'd clog the hole automatically even without glue, but I think the pressure differential would just squeeze them through.
It takes billions of dollars and many years just to construct things like subway systems in developed countries.
The only way I see a mars mission happening is launching remote controlled equipment over the course of decades to the red planet and building and preparing everything as much as possible before so much as the first human arrives. I don't see any other way it happens with how expensive and risk averse we are as a society these days.
And even then, the likely scenario is sending and constructing return vehicles for a very short human mission.
And that's all assuming we figure out how to get people from here to there in a space ship for so many weeks in the first place!
Maybe I'm just more pessimistic than the average HN user when it comes to sci fi stuff like this, I don't know. I just can't see humans investing the money to get over all these hurdles for a colony that we don't even know could work out currently-- we can't even make self sustaining habitats here on earth!
> assuming we figure out how to get people from here to there in a space ship for so many weeks in the first place!
Why do you think that's an unsolved problem? Genuine question. I thought that part is a straightforward engineering problem. (A very challenging one of course. I'm not saying it's not, just one where we have a lot of previous experience. I never thought that the fundamental possibility of it is in question.)
Well there are no solid designs on the table for doing it. Mostly because it's a chicken and egg problem of making plans to send people somewhere they can't come back from right now. But it's far from just an engineering problem; there is a huge human element to it:
For instance, we don't have a lot of experience with large groups of people in space for that long. We're talking at least 7 months each direction if they're coming back, plus waiting for the return window and executing it. That's an insane experiment in low gravity isolation that by itself hasn't been tackled-- most astronauts are only in space for 7 months at a time on average for a trip, and they need varying amounts of recovery afterward. We're talking about twice that, for an entire crew, plus time spent on the ground on mars in a lower gravity field than here on earth.
Then there's the fact that the crew will need to be large to be sufficiently redundant... and that runs into the problem of having many people in a small isolated space for such a long period of time. I think the largest crews we've had up there were around 10 people. A mars mission would need enough people to prevent everyone from dying if something went wrong on the way there, the wait for the window, and the launch for the return trip, and the return trip itself. I don't think we know how many people that would take currently.
I don't think we can confidently say that it's even possible until we have more experiments studying those things alone.
I'm not at all an expert these are just layman opinions and observations, so if I'm off base I'd like to know. But that's how I understand just the problem of going there.
Regarding the time it could take to travel between Earth and Mars, I recently saw a very interesting video on a concept called a "skyhook" that suggests it might be able to economically reduce the transit time to "just" two months or so, though I assume you'd still want to wait for an appropriate launch window, and in addition it probably wouldn't be operational in time to benefit the first few generations of travelers. :P https://m.youtube.com/watch?v=dqwpQarrDwk
> and that runs into the problem of having many people in a small isolated space for such a long period of time. I think the largest crews we've had up there were around 10 people.
Challenges of low gravity aside, this doesn't seem that different to a modern submarine. We have nuclear submarines with crews of ~150 that stay submerged for months at a time - the navy has to have some idea how to address the cultural problems inherent in packing 150 people into a tin can...
> It takes billions of dollars and many years just to construct things like subway systems in developed countries.
Much, if not most, of that being spent on lawsuits, as people block construction projects, hoping to extract maximum value for themselves now that they know the society needs their permission.
Having this in mind, I wouldn't be surprised if building infrastructure on Moon or Mars ended up being cheaper than in the US - there are no land owners up there just yet.
I'm pretty sure it's not true as most subway systems outside of the US (where we are not as lawsuit-happy) still cost billions of dollars and takes many years to construct.
I don’t know why people can’t face the facts. Maybe someday there will be the technology but right now it’s like cave men trying to build an aircraft carrier.
ya, you'd need multiples of these anyway, just for the redundancy. That said, it's fairly straightforward to put up separate walls that seal different compartments. The rectangular shape makes expansion and inter-zone connections a lot easier. Many air mattresses use similar techniques, and most inflatable watercraft have that redundancy.
You’re gonna have to provide a bit more context for that challenge, considering all the information already available about it. Which figure do you think is wrong?
The actual fuel cost to put things into orbit is quite small, on the order of $30/lb of payload. I've done this analysis on HN before, but the gist is that LOX and kerosene are about the cost of milk, and roughly as dense on average, and you need about 20-30 lbs of propellant for each lb of payload. The rest of the cost comes from labor and amortizing the launch vehicle and infrastructure. The cost floor is <stick wet finger in breeze> probably around $100 (2019 dollars) or so per pound. Not great, but not "extraordinarily expensive." This is without going to gun-assisted schemes for durable raw materials and the like. (Incidentally, this seems insane to me. It seems like you want rockets for people and fragile goods, and guns for anything that can take a few hundred to a few thousand gees or more, like steel or aluminum or water (ice) or.... But, this is just a SWAG. There could be hiccups there preventing a gun-assist cost floor much lower than that for rockets.)
I would guess by coating the floors/ground with sealing coating (and walls and ceilings if you're underground).
It might need to be nice and thick to withstand wear, but maybe not that thick depending on how tough the sealant is, how regular the surfaces and how well maintained.
Just curious though -- I'd always assumed domes were just a fun sci-fi illustration/trope because they look cool -- not that they were necessarily taken seriously by engineers.
Is the author just responding to that sci-fi concept (same thing as, spaceships don't make a whoosh sound in space), or are there more serious Mars plans that have genuinely proposed domes? I feel like the author isn't quite clear who he's responding to.
you get the advantage of just having to ship an inflatable skin and then you just dig out a hole some fraction of sphere, put the bubble in and then fill the dirt back inside the bubble, now it's pressure supported and anchored.
> It’s a pitiless frozen vacuum. The Earth’s south pole in the middle of winter is closer to a beach in Hawaii than the nicest place on Mars on the nicest day of the year.
Wow, on the surface pictures made by the rover, it looks like a hot desert. I understand that the lack of water causes this drastic difference in appearance, but never would have imagined the difference to be so big.
It’s the near-vacuum, plus the radiation environment, mostly. Temperatures on Mars can rise above freezing in the tropics, on a particularly warm summer day, but the average temperature on the planet is several tens of degrees C on the negative side. The author’s point is, I believe, that even in the southern polar night a human being can survive, for a while, with stone age technology. Whereas if the atmosphere around you isn’t breathable there’s not much you can do without (literally) space age gear.
Why did the author go to all the trouble to write this when within their own argument it’s obvious that it’s impossible for humans to survive and flourish without Earth?
OK. Let’s assume the technology works out, and that this is realistic:
> the Mars city will need teams of specialists
> On Mars, SpaceX hopes to get by with “only” a million people and a lot of manufacturing automation
> What is the per capita area requirement on Mars? In a future post I’ll estimate this more rigorously but I believe it’s on the order of 10,000 sqft
How do you bootstrap to get there?
> If a Mars base is doubling its population every launch window, then the 5000->10000 person increment
So, let’s say you are such a specialist. What would entice you to sign up for one of the first flights?
Given the disadvantages (a return flight will be years out, if ever in your lifetime, and those in the first 10 or so flights will have to trust that 200-ish further flights will follow) I doubt ‘fame’ and ‘adventure’ will cut it (possibly for some people, but try finding 25,000 or so for those first flights, with the restriction on getting a good mix of expertises and a good psychological mix)
I can think of:
- coercion by your government
- Earth being wasted enough to make Mars look enticing.
- lots of unmanned flights, to ensure that the first flights going there have an escape vehicle, if needed.
Assuming my family is grown (and thus my direct life responsibilities fully attended), I'd sign up.
Recall the older generation that cleaned up at Fukushima.[0] These are folks that knew their activities would be uncomfortable, may cause their death, but ultimately was absolutely vital to the benefit of all mankind.
This view on life is not constrained to a single culture or background. Self-sacrifice in such a way is often considered the highest pinnacle of morality -- even under the auspices of selfish genes since the act does not directly benefit descendants. Planting trees in your later years that the fruit may be enjoyed generations after.
You may ask if I have any special skills. I do, but suppose I don't. In such a place you will need grunts. And I'd be happy to join in to build humanity's insurance policy to be a bit broader.
All depends on the cost-benefit evaluation at the margin. To fill the resource, the prime candidates may be too few to recruit, and the people with grown children still relatively young and healthy available to make the trip and contribute sufficiently.
Have the man studied engineering? I don't feel so. Too much drama for a trivial issue.
Point one, if a dome is in tension, you have not put enough weight.
Point two, tents are more manufacturable and robust for as long as cost is concerned.
Point three, massive human space colonisation will only happen long, long after we will get manufacturing automation, automated resource extraction, automated farming, and power production to "sci-fi" levels and above.
We are not even 1% done on that, and that's the biggest point. Without getting to at least 1% on that scale, the talk about even ~100 people research outposts in space are pointless.
Adding to that, once humanity will reach that level, the entire idea of going to space for something we don't get on earth will look silly.
Once we get robots to the point where one can get a skyscraper constructed with a single mouse click, it will likely wouldn't matter much more if that skyscraper will also have to be airtight and have life support installed.
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[ 2.9 ms ] story [ 240 ms ] threadIt makes me sad to think that exploration and settlement of the solar system would take with it this kind of thinking, which is dangerously close to rendering the Earth uninhabitable.
The Earth (and Mars...) are, in some sense, closed systems, in that exploitation of resources has a hard limit beyond which we're looking at biosphere collapse, or just plain resource exhaustion.
Maybe we could use space exploration to come up with a different way, and then roll that back into how we live here on Earth.
People have a big impact on our environment, and the definition of "environment" keeps ratcheting up with the scale of humanity... As the number of people, the scale of our impact, and our knowledge of this impact our definition of "our environment" expands.
That's not likely to change. We're not going back to our environmental niches and we're not going to be a impact-neutral observer of "the natural environment" either. We're going to maintain our place between gods and beasts, so to speak.
That doesn't mean we don't/won't evolve. There is definitely no sense and future in bluntly walking in to environmental hard-limits like climate change, biodiversity crisis or any other pressing catastrophe.
But.. perfecting ourselves to the point where we've "moved beyond" resource use shaped by our wants and needs, exploitation...
In any case, I think the environmental ethos of the future can be left to future people. It will inevitably be shaped our ours' mistakes, and their consequences.
https://imgur.com/a/h92bLIp
In other words, your lip needs to be distributing force onto a sufficient volume of ground to make up 100_000 metric tons of martian soil, per meter of circumference.
Basal fiber is about 3GPa tensile, call it a MoS of 6 for a neat 500MPa working strength.
If you plug int wolfram alpha `1 atmosphere * 1 square meter / 500 MPa` you get 2 cm^2 of support (tethering) per sq m of roof. That's reasonable.
But here's the rub: compressive strength lags tensile strength. Even granite is a mere 130 MPa. So even a strut which has some compression resiliance is not gonna be enough to fully abate a collapse. So it's very likely a Martian structure would have some arc to it, as it both benefits tension under nominal operation and some compression in failure mode, at least long enough to keep pressure from dropping too low.
I imagine rip-stop at all sorts of scales will be implemented. It's not gonna be like an inflatable golf dome.
https://www.engineeringtoolbox.com/compression-tension-stren...
https://en.m.wikipedia.org/wiki/Ultimate_tensile_strength
Its a major labor sink to build and maintain and dunes could cause a catastrophic failure. Could make an interesting sci fi novel about "emergency EVA to run bulldozer drones to spread sand to prevent dome collapse".
In the end, rather than the nightmare of making a 3000 meter diameter dome deep enough under ground that dune forces will have no effect (using h-bombs to excavate?), just make thirty 10 meter diameter tunnel boring machines and run them 10 kilometers in different directions.
The linked article's tube tent is not a bad idea for surface greenhouses.
https://en.wikipedia.org/wiki/Walther_Bauersfeld
Sounds like a distinction without (much) difference.
A structure like this might make sense for a shorter mission - but considering the thought experiment asks what structure would be suitable for a long term Musk-style settlement I don't think thin ETFE would be enough.
At least part of the radiation risk is temporary solar events, so perhaps you could use a slightly hardened version of ETFE as the author suggests but keep all human activity near regularly placed deep shelters to retreat to when radiation spikes are detected?
https://www.esa.int/Science_Exploration/Human_and_Robotic_Ex...
https://phys.org/news/2016-11-bad-mars.html
Maybe the living area buildings inside the tent can have a vestible / "dustlock" for keeping the dust outside, and outside those it just becomes standard to wear a dust mask.
Or, to put it another way, any structure capable of shielding against cosmic radiation should be capable of also holding air (we’ve gotten really good at that).
A thick roof without walls should protect you from cosmic radiations (some distance from the edges), yet wouldn't be airtight....
https://caseyhandmer.wordpress.com/2019/10/20/omg-space-is-f...
Underground may be the only way to live, given that radiation dosage is cumulative, 24/7, it may not be possible to live on the surface at all in inflated domes. Maybe they're better suited for equipment storage and agriculture.
I do expect to see Boring machines on Mars anyway.
Such a material would have other interesting uses, including spacesuits and spaceships.
You can vet people as much as you want but with the pop they are talking about someone’s bound to go crazy or be an agent of discontent. And then if they are settlers of course their children can be as varied as they are on Earth, which means the possibility of the same.
It might be a pedantic quibble but I can see power as the only "rational" sabotage motive. Which could include some disgruntlement. Either to oust management or rivals to gain control or possibly international politics where one thinks they can gain from the loss of the colony for the sake of their earth nation.
Suicidal can be taken as granted to be irrational and disgruntled relatedly as "so fed up they want to see everything collapse to make them suffer".
The promise of a ticket back to Earth and a shitload of money.
But maybe pressurizing an underground complex with walls made out of ...Mars is more difficult than building something on the surface?
Going underground seemed like it had limitless room for easy expansion.
I like the authors suggestion and it does sound better than a dome but living underground seems safer to me.
Cover a canyon (walls for free). Use lava tubes. Or search for any peculiar geological feature that is amendable. I don't get why the assumption is a completely flat, desert surface.
Cities on Earth are generally not being in canyons either, even though that would give you "walls for free" as well.
Cities on Earth don't need to be protected from toxic soil and hard UV radiation. Instead, most cities on earth have been built near rivers for cheap transportation. Castles and fortifications are built on hills for defensive value.
That's why photos from different Mars landers look often very similar - the regions they have landed in have been effectively selected to be similar. :) And of course these pictures shape how Martian surface looks like the public consciousness.
Things may be changing though, with the technology being developed for active obstacle avoidance, that might enable martian landers to land in a more complex terrain safely by analyzing the actual landing site and landing on a safe spot.
Still, you might still want some flat area near an early martian base/city, even just to make trucking stuff from/to landers that strayed of course during landing easier. Eq. not having one in the middle of a rock field and another on crater bottom. :)
I know tunnel boring is supposed to be getting cheaper and easier, plus on Mars you’d be starting from a blank slate rather than working around/under existing infrastructure. But for big tunnels you still need a big boring machine, and that would either have to be shipped to Mars or built on Mars.
To make a tunnel boring machine on mars you must first invent replicating nano mining/manufacture bots.
There are photos of lava tubes that are hundreds of meters wide and kilometres long. That's a lot of space shielded from radiation.
I am uncertain of the ergonomics of living spaces in artifical environments - I suspect even the experts are uncertain and even if they invested heavily they would discover design mistakes to correct in future iterations.
* At least, automated enough that it's not bottlenecked by humans operating robot arms at a 30 minute feedback delay.
In total the US already spends half a trillion on R&D per year. The US military spends a trillion on R&D every 15 years and the IT industry does about the same, and bear in mind most of the research these organisations are already doing would be directly relevant to a project like this. So in a way we're already doing it, and I don't see any from-scratch full-civilization self replicating technology architectures coming along on the horizon even as a theoretical exercise. Even for something like interstellar probes at least we have outline designs.
Does anyone else have good examples of popular scifi tropes which have formed an engineering zeitgeist, but which are realistically very suboptimal?
I want try this here to see how feasible it is for co trolled environmental spaces.
If you want to get fancy, coat them with a glue that bonds to the ceiling material, and they'd fix the leak too! At least temporarily. My first thought was that they'd clog the hole automatically even without glue, but I think the pressure differential would just squeeze them through.
It takes billions of dollars and many years just to construct things like subway systems in developed countries.
The only way I see a mars mission happening is launching remote controlled equipment over the course of decades to the red planet and building and preparing everything as much as possible before so much as the first human arrives. I don't see any other way it happens with how expensive and risk averse we are as a society these days.
And even then, the likely scenario is sending and constructing return vehicles for a very short human mission.
And that's all assuming we figure out how to get people from here to there in a space ship for so many weeks in the first place!
Maybe I'm just more pessimistic than the average HN user when it comes to sci fi stuff like this, I don't know. I just can't see humans investing the money to get over all these hurdles for a colony that we don't even know could work out currently-- we can't even make self sustaining habitats here on earth!
Why do you think that's an unsolved problem? Genuine question. I thought that part is a straightforward engineering problem. (A very challenging one of course. I'm not saying it's not, just one where we have a lot of previous experience. I never thought that the fundamental possibility of it is in question.)
For instance, we don't have a lot of experience with large groups of people in space for that long. We're talking at least 7 months each direction if they're coming back, plus waiting for the return window and executing it. That's an insane experiment in low gravity isolation that by itself hasn't been tackled-- most astronauts are only in space for 7 months at a time on average for a trip, and they need varying amounts of recovery afterward. We're talking about twice that, for an entire crew, plus time spent on the ground on mars in a lower gravity field than here on earth.
Then there's the fact that the crew will need to be large to be sufficiently redundant... and that runs into the problem of having many people in a small isolated space for such a long period of time. I think the largest crews we've had up there were around 10 people. A mars mission would need enough people to prevent everyone from dying if something went wrong on the way there, the wait for the window, and the launch for the return trip, and the return trip itself. I don't think we know how many people that would take currently.
I don't think we can confidently say that it's even possible until we have more experiments studying those things alone.
I'm not at all an expert these are just layman opinions and observations, so if I'm off base I'd like to know. But that's how I understand just the problem of going there.
Challenges of low gravity aside, this doesn't seem that different to a modern submarine. We have nuclear submarines with crews of ~150 that stay submerged for months at a time - the navy has to have some idea how to address the cultural problems inherent in packing 150 people into a tin can...
Much, if not most, of that being spent on lawsuits, as people block construction projects, hoping to extract maximum value for themselves now that they know the society needs their permission.
Having this in mind, I wouldn't be surprised if building infrastructure on Moon or Mars ended up being cheaper than in the US - there are no land owners up there just yet.
Given that a tear would result in catastrophic depressurisation.
It might need to be nice and thick to withstand wear, but maybe not that thick depending on how tough the sealant is, how regular the surfaces and how well maintained.
Just curious though -- I'd always assumed domes were just a fun sci-fi illustration/trope because they look cool -- not that they were necessarily taken seriously by engineers.
Is the author just responding to that sci-fi concept (same thing as, spaceships don't make a whoosh sound in space), or are there more serious Mars plans that have genuinely proposed domes? I feel like the author isn't quite clear who he's responding to.
Still interesting either way.
you get the advantage of just having to ship an inflatable skin and then you just dig out a hole some fraction of sphere, put the bubble in and then fill the dirt back inside the bubble, now it's pressure supported and anchored.
Wow, on the surface pictures made by the rover, it looks like a hot desert. I understand that the lack of water causes this drastic difference in appearance, but never would have imagined the difference to be so big.
You see a canopy flowing as-far-as-your-eye-can-see over a vast red desert oasis.
The oasis sprawls out to form lakes, ponds, and streams and slowly terraforms the landscape.
An autmosphere grows using natural systems like trees, shrubs, vines, and prairy.
> the Mars city will need teams of specialists
> On Mars, SpaceX hopes to get by with “only” a million people and a lot of manufacturing automation
> What is the per capita area requirement on Mars? In a future post I’ll estimate this more rigorously but I believe it’s on the order of 10,000 sqft
How do you bootstrap to get there?
> If a Mars base is doubling its population every launch window, then the 5000->10000 person increment
So, let’s say you are such a specialist. What would entice you to sign up for one of the first flights?
Given the disadvantages (a return flight will be years out, if ever in your lifetime, and those in the first 10 or so flights will have to trust that 200-ish further flights will follow) I doubt ‘fame’ and ‘adventure’ will cut it (possibly for some people, but try finding 25,000 or so for those first flights, with the restriction on getting a good mix of expertises and a good psychological mix)
I can think of:
- coercion by your government
- Earth being wasted enough to make Mars look enticing.
- lots of unmanned flights, to ensure that the first flights going there have an escape vehicle, if needed.
Recall the older generation that cleaned up at Fukushima.[0] These are folks that knew their activities would be uncomfortable, may cause their death, but ultimately was absolutely vital to the benefit of all mankind.
This view on life is not constrained to a single culture or background. Self-sacrifice in such a way is often considered the highest pinnacle of morality -- even under the auspices of selfish genes since the act does not directly benefit descendants. Planting trees in your later years that the fruit may be enjoyed generations after.
You may ask if I have any special skills. I do, but suppose I don't. In such a place you will need grunts. And I'd be happy to join in to build humanity's insurance policy to be a bit broader.
[0] http://www.cnn.com/2011/WORLD/asiapcf/05/31/japan.nuclear.su...
Point one, if a dome is in tension, you have not put enough weight.
Point two, tents are more manufacturable and robust for as long as cost is concerned.
Point three, massive human space colonisation will only happen long, long after we will get manufacturing automation, automated resource extraction, automated farming, and power production to "sci-fi" levels and above.
We are not even 1% done on that, and that's the biggest point. Without getting to at least 1% on that scale, the talk about even ~100 people research outposts in space are pointless.
Adding to that, once humanity will reach that level, the entire idea of going to space for something we don't get on earth will look silly.
Once we get robots to the point where one can get a skyscraper constructed with a single mouse click, it will likely wouldn't matter much more if that skyscraper will also have to be airtight and have life support installed.