Domes are over-rated

Tuesday, November 22nd, 2022

Any article about Moon or Mars bases needs to have a conceptual drawing of habitation domes, but domes have significant drawbacks, Casey Handmer reminds us:

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.

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 tessellate 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.

Does this sound like an engineering nightmare? High tolerances, excessive weight, finicky foundations which are a single point of failure, major excavation, poor scaling, limited interior space, limited local production capability. At the end of the day, enormous effort will be expended to build a handful of rather limited structures with fundamental mechanical vulnerabilities, prohibitively high scaling costs, and no path to bigger future versions.

viaDomes are over-rated –’s blog.

Comments

  1. Freddo says:

    So the good thing about a dome is that while you are doing the extensive foundation engineering, you can cheaply add a number of underground levels. And the lack of rain/ground water – esp. under freeze/thaw cycles – makes that a much more feasible solution than on earth where our high value locations usually have a high water table.

  2. Altitude Zero says:

    So, has this Casey Handmer guy ever actually built anything? If so, what? If not why exactly should we be listening to him? He may be right in what he says, but lets see something that he has actually accomplished. Pie in the sky startups that promise to capture carbon using unicorn farts don’t count.

  3. Harper’s Notes says:

    Mars has a serious radiation problem. Almost no atmosphere. Almost no geomagnetic field. Don’t leave out solar flares and CME’s. Elon’s Boring company probably had something to do with the radiation problem? Elon likes rockets. Elon likes Mars colonization. Elon likes underground excavation. Connect the tunnels. Bode’s Law on the succession of the distances of the planets from the Sun led to the discovery of Ceres. Ceres is somewhat less than double the distance out from the Sun than Mars. Inverse distance squared so approximately 1/4th the radiation. 24 7 sunlight versus Mars planetary rotation. Put covered plants on Sun-nearside of asteroid, humans on farside. Still close enough to Sun to grow things. That’s my understanding. What am I missing?

  4. Isegoria says:

    I’m not sure how much he’s done, but from his resume we can see that he has worked at JPL, Hyperloop, and Caltech (as a postdoc and grad student).

  5. Altitude Zero says:

    I see lots of software development and theoretical work, not a lot of actual physical accomplishment. He’s smart, certainly, but I don’t really see anything operational – at least not yet. I’ll withhold judgement…

  6. Longarch says:

    These last few posts have really been slaughtering my sacred cows. I love zeppelins, geodesic domes, underground engineering, theoretical life support systems … and these last couple of posts have just been telling me that all my favorite parts of sci-fi stories will never work in my lifetime.

    Nothing to do now but drown my sorrows in whiskey and cosplay.

  7. Sean says:

    Domes are strong in both tension and compression.

    Manufacture the domes in a different way and they become far easier to build.Spray foam solves most of the problems. Don’t construct using panels.

    Domes are efficient in tension and compression. Pressure vessels (think 500 gallon propane tank) are built with hemispherical ends. Due to less bending stress, the thickness of the ends is 1/2 the thickness of the straight walls.

    Domes use less material. Even if the material used is weak in tension (like concrete), material can be added to compensate (rebar).

    It’s easy to insulate a dome using spray foam. The problems with acute angles disappears. And because the foam becomes a structural member, tolerances on the assembly of the frame can be larger and not lose strength.

    This means it’s easy to add openings, and easy to connect domes together. Then using many smaller domes instead of a single larger one won’t cause foundation problems.

    And you wouldn’t depend on membranes to contain the air.

  8. Steven C says:

    This article completely ignores the fact that the higher radiation on the surfaces of the Moon and Mars makes surface domes problematic. At the very least, a few meters of soil will be needed to cover the entire upper surface of these domes.

  9. Jim says:

    Freddo: “So the good thing about a dome is that while you are doing the extensive foundation engineering, you can cheaply add a number of underground levels.”

    You can cheaply add a number of underground levels? Interesting…

Leave a Reply