Domes are overrated
caseyhandmer.wordpress.com
caseyhandmer.wordpress.com
The benefit is that a colony on Mars would be an engine of innovation. People keep pointing out that NASA has produced hundreds of useful innovations (like space blankets). Imagine how many innovations would a colony of 500 people come up with when stranded there for months and years. It's not that we send them there with only sticks and stone tools, they'll have the most advanced technology we can fit them with, but they'll still find themselves in thousands of situations where their tools will be puny compared to their problems.
Some in this thread mention boring machines. Well, just after a boring machine cuts a few meters of tunnel, someone lines that tunnel with some concrete elements. Where's the concrete coming from on Mars? Oh, I guess they can make it locally. Great, where are the components coming from? I guess you can mine them locally, but you'd need to bore some tunnels for that. A bit of a chicken and egg. What if the concrete does not set exactly like on Earth, because, you know, there's not enough humidity in their air (and there's not enough air either).
These guys will face millions of problems. And they'll have no choice but solve them.
It's going to be awesome.
https://en.wikipedia.org/wiki/Mars_trilogy
Arkady wouldn't like this article.
While solar + batteries will last an Earth night or a Mars night, for something with a big enough population to be called a “colony” rather than a “base”, you suddenly find you need either a nuclear reactor, or some very big orbital mirrors, or a circumlunar powergrid.
None of these options are impossible, but they might make people prefer Mars.
Although not “eternal” in the original sense, they are sunlit for extended periods, well beyond the typical lunar day-night cycle.
What is the significance of such features? Permanently lit areas of the Moon are important for future habitation and use of the Moon for two principal reasons. First, these sunlit areas are prime locations for the establishment of solar photovoltaic arrays. The constant sunlight here means continuous generation of electrical power using solar panels. This solves one of the most difficult problems of lunar habitation, survival during the 354-hour lunar night. Prior to the discovery of the quasi-permanently lit areas, we imagined that the only feasible power source to survive this long night was nuclear reactors. Such a power system does not exist and would require several tens of billions of dollars to develop. So sunlit zones allow us to go to the Moon and stay there without this expense and technology development.
The second advantage of a sunlit area is that it is thermally benign. The surface temperatures at the lunar equator and mid-latitudes depend almost entirely upon incident solar illumination and range from less than -150° to over 100° C, a 250° temperature-swing over the course of a day. In contrast, the surface temperature of these quasi-permanent lit areas is nearly constant – a nice, toasty -50° ± 10° C. This simplifies the thermal design of surface habitats and equipment and greatly relieves the energy required for thermal control at an outpost.
The sunlit areas of the poles occur in close proximity to high concentrations of water ice and other volatiles at the poles of the Moon. Their presence indicates the lunar poles are the best places we have found off-planet for human habitation. Constant sunlight, benign temperatures, near the water and a great view – that’s prime real estate.
[]: https://www.airspacemag.com/daily-planet/new-light-on-the-lu...
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[1] https://en.wikipedia.org/wiki/James_Webb_Space_Telescope#Cos...
So for Mars, I don't think merely the opportunities for _any_ innovation, are a convincing enough argument, at least for those investing in Mars. For them the specific innovations around spaceflight and non-earth construction are indeed valuable, because of future expansions into space and first mover benefits, using Mars as a stepping stone.
As for the colony on Mars itself, I speculate that having somewhere outside of existing jurisdictions is also attractive for a lot of people; the new unclaimed West. Some may imagine this to become a scientist utopia, free from the restraining politics of Earth; others might be more cynical.
We will see.
[1] https://www.bbc.com/future/article/20130930-can-we-build-und...
Fundamentally that is how it is different from colonizing the ocean floor.
They’ll have the same or worse technology we already have on earth. They’ll have far fewer people and far less access to things to solve problems they didn’t plan for. But nah they’ll innovate and make great innovations, more than could ever be done here. I don’t wish to be rude but I honestly cannot understand for the life of me the rationale of this argument.
Solving interplanetary space travel is the most expensive form of procrastination I have ever seen.
(Myself I think we'll go when it's easy. The best way to make it easy is to work on relevant technology like nuclear fusion, automated manufacturing, CRISPR, and so on.)
There would have been indications in wave pattern. And they knew how to read these, as well as meteorological hints and knowledge of tides.
Nevertheless, in the context of this discussion, landing up on an inhabited island thousands of kilometres from here is a huge shot in the dark, and most hopeful colonists would have missed.
But on Mars, you don't have proper air and you don't have wild life for food. And you cannot easily leave for other better places.
Once the location is established, regular trade becomes much more feasible.
Good point. It would make sense to send robots in advance to manufacture huge stockpiles of air and food. Which is of course beyond present technology.
With enough money you could set up 1000s of semi-autonomous robots to mine, mill, farm, .. and make more robots to help.
They win on arbitrarily long timelines, but they start to look a lot worse if you want ROI in under 10 years. It takes a ton of energy to reach and return from most asteroids in a sensible period of time. With unlimited time you can use various slow tricks to park them in accessible orbits, but this is a gold rush not a 100 year infrastructure project.
O'Neill had it right IMO, Lunar and Martian mass drivers firing up to Lagrange points are going to win. In the early days those bodies win because you can iterate on your mining tech way, way, way faster and keep up with the falling cost curve. In the later days economies of scale win the day.
Isn’t that a bit like saying if you toss a 10-year-old off a boat, he has no choice but to swim?
The focusing effects of a clear goal are real and powerful. But lets not pretend that the default option isn’t death.
Trivia question: did you know that most of the Mayflower colonists died? Ahem, I mean, all of them died. All of us will die sooner or later, some people find it meaningful to go where no one has gone before, even if that means danger of death.
So should we spend trillions more on military? Well maybe it is just that spending trillions on research towards anything tend to lead to some useful inventions on the side. But what if we spent the same amount of resources on researching something actually useful for humanity? We might still get the side inventions.
Building a colony on Mars is a useless waste of money.
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...
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.
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...
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.
This is also bad news for trying to establish any sort of agriculture.
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.
> 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...
They have problems to solve. It doesn't mean that it's wrong to spend a (relatively) tiny amount of money to give people something to aspire to, and to take pride in accomplishing together. We can do two things at once.
You're only focus on the space program because it's technically similar to food insecurity. But you're ignoring the 50% of the economy which is focused on -- let's be honest -- irrelevant shit. Incredible sums of money (and time and effort) go towards entertainment (hollywood), fashion, jewelry, vacations, and other luxuries.
If you want to divert more resources towards solving world hunger, take it from Hollywood. You don't need to strip bare a source of inspiration that unites people and moves humanity forward.
But, total resources for a Mars colonization effort seems like an order of magnitude more expensive than a simple space program for the benefit of an order of magnitude fewer people. In addition, the capital that is contributing to these efforts (ie Bezos and Musk money) is much more concentrated and can be mobilized in a much more precise manner. I don’t see Mars colonization as a source of inspiration outside of these SV types, and that’s not a significant enough population for me to find this justifiable.
The other is technical (for now) -- hard, but trivial.
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.
Does anyone else have good examples of popular scifi tropes which have formed an engineering zeitgeist, but which are realistically very suboptimal?
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.
Space habitats so far look more like submarines. It’s a bunch of tubes with bulkheads. But they don’t scale, and some of the biggest ones so far are in fact inflatables.
If you nested inflatable structures, the forces on them are due to the pressures between the layers. You could run an outer chamber that requires a respirator, an inner one for living space, and a third for medical. An alarm system in each layer could begin capturing atmosphere in the event of a breach, with emergency venting for over pressure. You would only risk half of your air to a single failure.
The Eden project uses hexagons panels that resemble a blister on bubble wrap. No accuse angles there. And why can’t you cable a dome down the same as this design?
The idea of a dome is volume. If you aren’t going to build upward in the dome, why bother? Building upward avoids interfacing with the envelope.
If you could work out how to construct a dome over the top of an existing dome, you wouldn’t even have to move. Just deconstruct the inner dome and begin expanding outward.
Also, his idea about hanging buildings from the wires is bunk. If you hang your buildings from the tensile structure that is buoyed by air and you have a rupture, now your buildings are going to collapse. Likely onto other buildings. Since his design has no compressive strength at all there is no way to address that issue.
[edit] what makes it more bunk is that in order to have tall structures, the entire habitat has to be the same height as the structure, instead of placing them near apex of a hemispherical structure. So he's just doubled the volume versus a sphere. Also if you make a bubble structure that tall you have to handle the pressure on the walls. I don't see where he mentions walls at all except when talking about how dome walls suck. Not as much as trying to pressurize a rectangular pressure vessel! The only place his solution shines is in 'doming' a valley or a canyon, where a dome has a host of other problems he hasn't even covered.
I can't remember if the bubbles on the Eden domes contribute strength to the structure, but I expect you could design them to do so. Then the structure begins to more resemble a bouncy castle (like the ISS inflatable hab unit).
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.
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.
This was too a problem on a mars rover solar panel, can't remember which one.
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.
Given that a tear would result in catastrophic depressurisation.
If you step out of the parochial world where we happen to live on this planet, the fact that every one of our manufacturing processes is built around an ambient acceleration of 10 m/s^2 is weird and limiting. Beyond the freedom from gravity, orbital manufacturing provides for absolutely perfect vibration isolation (see LISA mission for an example).
Made in Space Fiber / FOMS is just the tip of the iceberg. Semiconductor fabs are going up there sooner or later.
See Made in Space fiber[0] for an early example - they're producing best-in-class optical fibers which can't be made on Earth because convection introduces crystalline impurities. Their value per kg is attractive enough to make this a profitable business with today's launch costs.
As launch costs drop and people explore this space we're going to discover a _lot_ of such problems.
Solutions / mixtures essentially don't separate in micro-g so you can grow much better crystals, smelt very high entropy alloys, do all sorts of awesome tissue engineering, etc.
The vibration isolation thing is also a huge force multiplier for all this. Ultra-precision manufacturing is a game of complete and total process control. Right now we spend absurd sums on isolation systems to block vibrations from the truck driving by half a mile away. In orbit you just make sure anything with moving parts is on a separate free body from your isolated component and they fly in formation. The LISA mission is doing this to position ultra-perfect reference objects and detect gravitational waves with baselines measured in thousands of kilometers.
[0]: https://madeinspace.us/capabilities-and-technology/fiber-opt...
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.
[0]https://en.wikipedia.org/wiki/Terraforming_of_Mars#Challenge...
* 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.
Sounds like a distinction without (much) difference.
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.
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.
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.