Domes are overrated

Sunday, December 8th, 2019

It is an unwritten rule of space journalism that any article about Moon or Mars bases needs to have a conceptual drawing of habitation domes, Casey Handmer notes, but domes are overrated:

Domes feature compound curvature, which complicates manufacturing. If assembled from triangular panels, junctions contain multiple intersecting acute angled parts, which makes sealing a nightmare. In fact, even residential dome houses are notoriously difficult to insulate and seal! A rectangular room has 6 faces and 12 edges, which can be framed, sealed, and painted in a day or two. A dome room has a new wall every few feet, all with weird triangular faces and angles, and enormously increased labor overhead.

Domes

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.

Once a dome is built and the interior occupied, it can’t be extended. Allocation of space within the dome is zero sum, and much of the volume is occupied by weird wedge-shaped segments that are hard to use. Instead, more domes will be required, but since they don’t tesselate, tunnels of some kind would be needed to connect to other structures. Each tunnel has to mate with curved walls, a rigid structure that must accept variable mechanical tolerances, be broad enough to enable large vehicles to pass, yet narrow enough to enable a bulkhead to be sealed in the event of an inevitable seal failure. Since it’s a rigid structure, it has to be structurally capable of enduring pressure cycling across areas with variable radii of curvature without fatigue, creep, or deflection mismatch.

Comments

  1. CVLR says:

    Martian lebensraumen will be subterranean.

    Once you can “do” air, hydroponics, and sunlight artificially, the reasons to live on the surface dwindle remarkably. People already spend most of their lives in buildings or in cars between buildings, and you can move all of that underground with little trouble.

    Sunlight, in particular, is interesting. Living without it really sucks. But if you do it right, and if you’re excavating in rock, then you can make almost arbitrarily large parks indistinguishable from an Earthian summer’s day.

    Rock also solves most of your atmospheric control problems. Underground you aren’t quite so vulnerable to the Universe’s many small bullets.

    Elon Musk is building tunnels for some probably totally unrelated reason.

  2. Kirk says:

    I don’t think that the future of off-planet living space includes the vast architectures many hypothesize.

    Instead, I strongly believe that it’s only going to take one or two major disasters, coupled with the inherent paranoia you’re going to need and develop about life support architecture, before everything goes small and cellular. Large, open spaces ain’t happening, because they’re so vulnerable. You’ll likely never see the vast open-air parks we theorize, at least not built by the natives. The only people lacking sufficient caution and due paranoia are going to be those who’re recent immigrants to the vacuum, and who happen to have large reservoirs of living planetary resources close by. Deep space is all gonna be tiny closed systems, joined but easily sealed off from disasters. Anything else would be nuts, TBH.

    The psychology of deep space dwellers is likely something we can’t even begin to grasp, at this point. I can see it going several ways, but which will prove to be more prevalent in the years ahead, assuming we can even make it work…?

  3. CVLR says:

    Yes, Kirk, that’s why you put everything under the surface. How much air will you lose by a failed seal if the seal in question is in a smallish hallway hundreds of feet above the main living areas, there are many redundant seals, and the intervening cubic feet are mainly solid rock?

    Not much, I suspect.

    I’m picturing smallish living spaces vaguely resembling a cross between the interior of that ship in the movie Passengers and some of the environments depicted in The Expanse, punctuated by vast vaulted parks with well-tended gardens, a few wooded areas, and an artificial ceiling made of some fancy material to fake Rayleigh scatter.

    The technology already exists. There were some PR articles about it a few years ago. I can’t emphasize enough how important this is. It is now possible to have a skylight in any room at any depth. The most secure facilities can be made almost indefinitely habitable. The implications are vast.

  4. Sam J. says:

    I can’t see any advantage to living on Mars at all. If we’re going to space the only reasonable and lowest cost solution is rotating space habitats. The only problem with this is it will take more time and a long dedication. Most likely the first two or three will be a big bust. Become completely covered in fungus or some other sort of disaster. The materials could come from the Moon and if you’re really adventurous the asteroid belt. I think the key would be remote mining with maybe a few technicians. The material could be launch O’neil style off the Moon with linear electromagnetic launchers.

    There’s lots and lots and lots of material for an extraordinary amount of space.

    “…It is now possible to have a skylight in any room at any depth…”

    Was that where they used big thick fiber optics???? Saw that a long time ago not sure if it’s the same you speak of.

  5. CVLR says:

    Sam,

    The advantage to living in Mars is protection from millions and millions of tiny Universe-bullets speeding around at unimaginable velocity. Plus, you get 37% gravity, which is infinitely better than microgravity. An enormous mass of highly stable rock fit for architecture is a big win also.

    What we need is interstellar travel, but that won’t happen with an average IQ of 100. Genetic engineering or artificial superintelligence are prerequisite.

    “Was that where they used big thick fiber optics???? Saw that a long time ago not sure if it’s the same you speak of.”

    Welcome to the future.

    This tech is in the same cool-factor league as flying cars, in my opinion.

  6. Sam J. says:

    You don’t understand what I’m referencing when I say “habitat”. It is spun for artificial gravity and has massive shielding of dirt.

    https://en.wikipedia.org/wiki/Space_habitat#Conceptual_studies

  7. Kirk says:

    For those of you arguing for the “vast open spaces” in habitat design, I would submit to you that you’re thinking about this in terms of a planet-bound mentality.

    Our descendants living in man-made constructed habitats are going to have an entirely different set of sensibilities and values. Vast open spaces they can get simply by going outside the habitats wearing pressure suits. The life support areas? They’re gonna have to be paranoid as hell, by necessity. Nobody is going to put their faith in some half-ass excavated or fabricated construction that’s prone to fracture or blow-out, not a scale of kilometers. Aside from that, the expense of maintaining that amount of atmosphere is simply going to be too damn high to risk losing it all in some massive blow-out due to either accident, misadventure, or malfunction.

    You’ll likely see a few of them built, as we leave Earth. After the first few major disasters, you’re not going to see any built at all–It will all be small, cellular structures that are massively redundant and backed up, even for small “settlements”. Nobody is going to build a habitat out past near Earth orbit that can’t function on its own, and which isn’t massively durable and redundant beyond belief.

    Imagine some settlement out near Jupiter or Saturn, suffering a blowout of their primary environment; what happens next to the mentality of the people observing that long drawn-out death spiral as the inhabitants run out of life support while everyone tries to reach them with aid? Care to imagine the modern equivalent of the Scott expedition, with the entire species watching what happens in delayed real time?

    Yeah; we’ll do it once, twice, maybe a third time: After that, it’s all going to be little bitty separate redundant cellular structures like beads on a necklace, dug in and built into whatever we wind up using. You will not see “eggs in one basket” solutions, ever. People just aren’t that stupid; they want vistas, they’ll go outside. Space-born aren’t going to be like us; they’re going to have to have a dichotomy in their heads, agoraphobic in terms of life-support areas, and the exact opposite in terms of everything else.

    I would imagine that the transition for them from deep space environments to planetary existence would likely freak many of them right the hell out, and rightly so–The space-born are going to have to have engrained habits and cultural traditions such that the idea of living out under an open sky will likely create a huge psychotic break for them. The idea of going to sleep in a non-airtight sealed compartment will likely be profoundly disturbing, and not having a pressure suit easily to hand at all times will be equally damaging to their psyches.

  8. CVLR says:

    Wrong video up above. Check out: https://www.youtube.com/watch?v=IsjfkjgA1Js or their site: https://www.coelux.com/en/products/index

    ///

    Reading comprehension isn’t the strongest in this thread, I see.

    Look, the post is about bases on the Moon or Mars. Okay? So I’m talking about bases on (in) the Moon or Mars. Where there’s rock. And gravity. And the rock provides plenty of highly impervious protection against countless of our Solar System’s immensely lethal bullets and our Sun’s radiation.

    And in rock, big underground spaces — reinforced, of course — aren’t really a problem. We’re talking about smallish-park-sized places here, okay? A football field or five in size and two or three (or four) trees high.

    Like, fuck. Seriously.

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