Random Thoughts: The Difference Between a Base and a Settlement (by Doug Plata)

There was an interesting comment by Doug Plata a few days ago that I wanted to repeat as a blog post. Background was discussing the idea of long-term stays on the Moon, similar to my old Lunar One Way to Stay (for a while) concept:

I would also like to point out that extending crew stay really blurs the line between what is a base and what is a settlement. I maintain that the real definition of settlement is when people are settling down. If people are settling down then that is a settlement. Settlements are not necessarily determined by size, economic independence, economic productivity, or the ability to have children. In particular, if retirees are moving away from Earth to stay, their settlement may start with a few people, the money for their settlement comes from their savings not from mining, and they will have no children with them. Yet, as the off-Earth retirement community grows, it will become increasingly obvious that it is a real settlement – Private housing, life support production, growing their own food, community meetings, perhaps it’s own governance structures, etc.

By way of historic analogy, consider a Mormon couple being sent to some distant valley to settle down, build their home, start growing their own food, raising animals, and preparing for the arrival for others. There may be no ore in the area and they may grow food for themselves. Relatives in the city might occasionally send them manufactured items that they couldn’t produce themselves. But they are settling and could rightly be recognized as being the first settlers for that area. Same with settling off Earth.

So, what does it take to do this initial type of settlement off Earth? It takes a habitat, adequate, ongoing life support including maintaining equipment, long-term protection from radiation and insufficient gravity amongst other things. These things are already needed for a permanent base. So, really, the only difference is that a base is a worksite and an initial settlement is a home. And a home is where you have a family. And a family can be as small as a husband and wife.

So, I for one think that the start of settlement doesn’t have to be many decades, trillions of dollars, nor need new, super massive rockets. Additionally, since a base can have a public (government) value and a base could be an initial settlement then a public-private program (e.g. Lunar COTS) could be funded largely by government funds yet also achieve the space advocacy goal of starting settlement.

I believe that this is very doable, I think that we should do it as a priority, and I think that it best that a free country, in particular the US, should do it before someone else finds out that the historic step of starting humanity’s first off-Earth settlement is as much a matter of choosing to do so rather than some huge technical or financial obstacle.

Food for thought.

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Jonathan Goff

Jonathan Goff

President/CEO at Altius Space Machines
Jonathan Goff is a space technologist, inventor, and serial space entrepreneur who created the Selenian Boondocks blog. Jon was a co-founder of Masten Space Systems, and is the founder and CEO of Altius Space Machines, a space robotics startup in Broomfield, CO. His family includes his wife, Tiffany, and five boys: Jarom (deceased), Jonathan, James, Peter, and Andrew. Jon has a BS in Manufacturing Engineering (1999) and an MS in Mechanical Engineering (2007) from Brigham Young University, and served an LDS proselytizing mission in Olongapo, Philippines from 2000-2002.
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10 Responses to Random Thoughts: The Difference Between a Base and a Settlement (by Doug Plata)

  1. ken anthony says:

    The only thing controversial about this idea is that some would consider it controversial!

    The next step is to realize that whatever the cost, slavery is not the justified consequence.

  2. DougSpace says:

    Here is a link to an AIAA paper that I published re: Reducing Mission Cost by Extending Crew Stay on the Moon and Mars: lunarcots.com/extended

  3. Paul451 says:

    Minor pedantic point: I think there’s a also difference between a “homestead” and a “settlement”, and you were describing a “homestead”.

    A single family is a “homestead”. You need a number of people, a number of families, a number of homes, before it’s a “settlement”. The line is fuzzy, Sorites Paradox’s pile of sand. But it’s there.

    (Not the point you were making, but it bugged me.)

  4. DougSpace says:

    Hi Paul, Fair enough. In my scenario the first hab would house four long-term couples (families) so from the start it begins to blur the line in that there would be multiple families. About 11 months later, three retired couples would arrive and would live in their own separate (but connected) habitat. During the next year, about three dozen private individuals (mostly retirees) would arrive. So, the homesteading phase would be fleeting if the definition required not just multiple families but multiple homes.

    Initially with easily shipped and assembled inflatables, the early settlement would look a lot like this Polish radio station (an actual photograph):


  5. MBMelcon says:


    Domes are efficient in mass/volume, but difficult to manufacture unless one blows bubbles, or makes facets for a geodesic. Half- or 5/8- cylinders are almost as good, and can be built from sheet goods with no curvature in one direction. Some of the tents we install in polar regions are geodesics, but most of the larger versions have an arch-like cross section. Many are modular, so you can choose length from a few meters to a few score meters. For an example, see the Mars Institute (not Mars Society) camp on Devon Island, Canada. I have not used any cylinders oriented like a silo, but it has been considered. – MBMelcon

  6. DougSpace says:

    Hi MBMelcon, I think that hirizontal half-cylinders or vertical cylinders and good design elements that should be incorporated within a base design if for no other reason than to add architectural variety. Initially I see inflatable domes being constructed on Earth and shipped to the Moon or Mars. So, I don’t see that much of a manufacturing challenge. The problems that I have with domes are that they don’t have a flat roof so regolith would need to be stabilized lest it sloughs off. Also, domes have a lot of wasted space unless one constructs multiple floors which with requires the shipping of a lot of mass or in situ construction. This is why I prefer a single-floor pancake-shaped habitat with internal tethers to keep the roof largely flat.

  7. Paul451 says:


    Cute. Someone was a SF fan.

    Although domes are a bad choice on Mars, IMO. (As are semicylinders, MBMelcon.) Domes/semicylinders are the optimum choice for external loading. On Mars, you need to think in terms of pressure vessels. Similarly, you aren’t going to have them plonked directly onto regolith, it would never contain the pressure. So the whole point of using a dome is defeated.

    I find that when you bring this up, people “solve the problems” (you can anchor the dome/semicyl against upward pressure, you can reinforce the base-ring against outward pressure, you can create an air-tight foundation, etc), but then… why persist with a dome? People start with the idea that a dome is “easier”, but when the problems are pointed out, seem to get hung up on keeping the image.

    The optimal pressure vessel is a sphere or rounded-end cylinder. You can get away with flattening them slightly to optimise usable volume. So either oblate-spheroids or elliptical cylinders.

    (And your internal roof-anchor allows you to tighten the ellipse further, obviously.)

  8. Paul,
    I totally agree that on the Moon or Mars an habitable volume is really a pressure vessel. Though it turns out there are weird things you can do when you combine pressure vessels and cables/tendons:


    This was a prototype I saw at NASA LaRC, for an inflatable airlock. I don’t think I fully grok how the structural mechanics works, but they can use this to make shapes that depart quite a bit from sphere/cylinder pressure vessel shapes, and also to lower the membrane stress in some areas to make it easier to make zipper style flexible seals. Not sure this is what you’d want to do for a lunar or martian hangar, due to the dust, but it’s a clever way to make an arbitrarily big “dry dock” in space that could have an opening big enough to allow a full spacecraft in and then have it worked on in a shirt-sleeves environment.


  9. Paul451 says:


    The two shapes in the pdfs were the two shapes I considered optimal: Oblate spheroids and (rounded-end) elliptical cylinders.

    The optimal pressure vessel is a sphere or rounded-end cylinder. You can get away with flattening them slightly to optimise usable volume. So either oblate-spheroids or elliptical cylinders.

  10. DougSpace says:

    With the objective of settlement in mind, I think that having the habitats where regolith is located makes for easy shielding. I prefer a singular large, thin-walked habitat (think pancake) that could be delivered in a single payload delivery. I call it the UniHab.

    ‘Construction’ would be a matter of wheeling out the packaged UniHab and opening the valve on a container of condensed air. Against the vacuum, it wouldn’t take much to unroll the UniHab. With internal, vertical tethers, a broad roof could be kept relatively flat. I calculated that one would need about one cm diameter tethers about every 5 meters.

    After the UniHab is unrolled, it could be deflated to lower the roof to ground level. Then telerobots push regolith onto the top of the UniHab for basically as long as the telerobots keep working up to several meters of regolith thickness. With the flat roof, one wouldn’t need to 3D print the regolith as ESA envisions, put regolith into end-to-end sandbags as Bigelow envisions, make lunarcrete, or other such complications. Just push the dirt on top, inflate, click on vertical supports for a measure of safety, push dirt against the sides and you’re done.

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