[...] associated with such an endeavour, we have looked at the structures available to us, we have even detailed a particular hangar-like structure that might use locally mined materials. Now, we look into the possible infrastructure elements that [...]

Only some quick thoughts on Mr McClatchie's comments:

Of course the ideal shape in terms of building a pressure vessel from a stress point of view would be a sphere or a tube with spherical ends.
BUT, spheres and cylinder tend to roll! Astronauts need a flat floor (we're not at zero g like Bigelow in Earth orbit).
The presented structure tries to deal with these and many other issues. It has structural hinges at the intersection of arch and flat floor, so there is no issue with stress concentration at the corners.

So many people talk about compensating dead loads on the structure with internal pressure. From my point of view there are at least 3 main load combinations one has to consider and the structure has to resist all of them:
1. Pressurized with no dead load in place (just before the regolith cover is put in place)
2. Regolith cover + Internal pressure (main operating condition and only here you have a balancing effect).
3. Catastrophic decompression with cover in place. I don't think we should completely rule that scenario out. The structure should at least work long enough for the astronauts to escape into the next airlock.

The presented design is by far the only or the best solution. I don't think such a solution even exists. But there are very many boundary conditions (many, many more than I mentioned here) and an adequate design has to consider all of them.

Best regards,
F. Ruess

You probably want a cylinder, with spherical ends, just like Bigelow's inflatables. Then, you want to bury this thing, probably by putting it into a preexisting ditch, tethering it into place, and then detonating a series of small explosives to slump the sides onto the module, a little bit at a time. You do this with a bunch of modules and then find out which ones survived.

One of the interesting things about 1/6 gravity is that 1 atm of air can support 21 meters (!) of 3 g/cc overburden. There is a lot of margin between the amount of material required for adequate shielding and the maximum you can dump on the structure without crushing it.

Also, 1 atm of air is not much mass, about 1 kg/m^3. So, if you want 120 m^3 per person, you need just 120 kg per person for the air necessary to support the structure. The carbon fiber necessary to contain that might weigh 30 kg. So, the balloon structure isn't the difficult part here. The assembly will be difficult.

Finally, your pressure vessel will develop leaks, and these will have to be patched from the inside. You need a mechanism to find the leaks, probably a smoke generator.

[...] – Building a Base on the Moon: Part 3 – Structural Design "To achieve inexpensive construction, as much local material must be used as possible. The [...]

The only problem that I see is what do you do if a hole is punctured through one of these slabs? But I guess that is where Bigelow's inflatable technology (lining the walls) could come in.

[...] O'Neill, Ian "Building a Base on the Moon: Part 3 – Structural Design" Universe Today 02/20/2008 On-Line Text [...]

[...] continuará en el próxima entrega. Autor: Ian O'Neill Fecha Original: 20 de febrero de 2008 Enlace Original Articulos RelacionadosConstruir una base en la Luna: Parte 2 – Ideas de hábitat Los planes [...]

This study mentions the point of “[o]ne-sixth terrestrial gravityâ€? being a key factor in influencing the structural design of the habitats. The key phrase I noted was “structural designâ€? — to me, that means the ability to use large and otherwise heavy materials like concrete or regolith, or even taking the matter of structural load-bearing into new consideration. That’s fine and all, but my thoughts actually are with regards to that 1/6 G environment and its influence on the habitat’s dimensions and internal layout:

Whatever they plan for the habitat, they need to apply lunar-based human factors, meaning they must throw away the Earth-based 1-G paradigm. One big example: where interior ceilings come into play. I've seen video clips of people walking inside a base mock-up showing off airlocks, beds and such. Then I'd look over their heads and notice that these folks are all walking around with a ceiling that is aprx 12 inches above a typical head. At first blush that looked acceptable get around in. But once in lunar gravity, people will not be able to walk like an Earthling (or float length-wise like on the ISS). I foresee dented ceilings and multiple cases of concussions — unless you either train the crew to walk with extreme slowness or with a bent-over posture (that'll do wonders to their spine), or issue everyone a hardhat… Or NASA (or whoever gets to design this) can make sure the habitat will have sufficient headroom to handle all the expected hopping.

Also, anything else that relies on gravity: Equipment like ladders; furnishings like sinks, showers, and (especially) toilets – well, you get the idea. If NASA has their space human factors department involved at all with this, I hope with all due respect that they are doing more than just figuring the layout of controls.