As others mention - soft inflatables are the way to go.
First, a lot lighter than metal. Second, the unit is sealed airtight (probably complete with airlock door) back on Earth where quality checks are a lot easier, rather than trying to seal things on the fly in a vaccum. Third, plastics “fold up” to a smaller size more flexibly than metal, and unlike the OP’s proposed idea, is not limited to any specific shape.
The airtight shape is the simplest part of the process of creating a base. The next steps include insulation, putting internal structures in place like walls and floors, etc. Plus, you’d want multiple separate modules so one “incident” does not compromise your entire habitat.
I think you need to have one of the metals or other material applied in strips. That may not be enough to force the action though. I am just wondering about the concept. If it has been proposed or would work.
Ah, yeah, that would work, but then again if you’re going to the trouble of doing that, you could probably just weld on some eye loops and use wires to pull it into a cylinder shape; once you join the mating edges, the wire tension would no longer be required
Just occurred to me to mention… the sort of technology you’re describing is adjacent to a field of inquiry popularly known as ‘4D materials’ - where a product is designed to autonomously change its 3 dimensional shape over the dimension of time (hence 4 Dimensional Material)
Along these lines, I’ve seen demonstrations where you can put a flat sheet of plastic on a light table, and it folds itself up into an intricate shape. The plastic itself is fairly normal, one of the ones that shrinks when hot. You mark lines on the sheet with a black marker, and heat it up to just a little shy of its shrinking temperature. When you put it on the light table, the black ink absorbs heat from the light, and contracts on the side of the surface with the marker on it, causing it to fold along the lines.
The demonstrations I saw were all just things like a net of a cube folding into a cube, but you could probably do some simple origami, too (probably the bird base, for instance, though it’d be tough to get it the last couple of steps to a crane).
One problem with a bimetallic hoop is that rolling metal into a hoop is trivial. You just need a device with three rollers. It could easily be shipped to the moon, along with a robotic welder to weld the hoops together (althpugh welding in a vacuum has its own issues).
The point is that the bimetallic design only solves a trivial problem, while introducing many more. Once you have your hoop the real work of turning it into a habitat would be 99% of the effort, and that effort would be better done on Earth. Hence the inflatable habitats.
The bimetallic hoop might have other applications, however. Say, if we need storage quonsets for harvested material. Throw a flat sheet on the regolith, wait for the sun to turn it into a hoop, connect it together and stand it up, and you’ve got a place to pile tailings from oxygen harvesting, or recovered iron or titanium, or whatever.
It’ll probably still be better to build them out of sintered regolith bricks, rather than shipping metals from Earth, though. But maybe other uses will arise.
Good replies.
Inflatables are a great way to go. But need internal structure to attach things to. Of course the tube idea would not be super strong either. I suspect it would need to be quite thin if the idea would work at all. But a metallic shell might make internal attachment easier.
I really wonder if the basic idea is feasible. How thick a sheet of metal could actually bend back into shape under just bimetallic expansion contraction forces? I know it can open and close vents and other mechanical actions. But I suppose leverage may be employed in those instances as well.
The ones that I have seen use a layer of copper for “health” reasons, basically that copper does have some natural antimicrobial properties.
Some of the woo folks have latched on to this and think that copper is some sort of mystic miracle healing material, or at the very least is much better than those “evil” plastics. Once you get past the woo stuff, there is actually something to copper preventing bacteria from growing in your water bottle.
I have never seen a water bottle that used copper for thermal insulation. Given the thermal conductivity of copper, I can’t imagine that would work very well. Copper does however work quite well at preventing little buggies from growing inside your water bottle in a way that BPA plastic won’t.
Pretty sure the things RedSky has seem are stainless steel thermos containers where there is a vacuum in the wall between the outer and inner layers of the container, and perhaps the inside walls of the vacuum gap are plated with copper to mitigate losses via radiation through the vacuum layer (so the liquid placed in the container never touches copper, because that would be a terrible idea anyway. Many drinks are acidic. Copper is easily eroded by acids, to form soluble salts. Most copper compounds are pretty toxic to humans)
So a thermos flask, but made from stainless steel and copper, instead of the older glass and silver.
‘Bimetallic’, whilst I suppose technically sort of true, isn’t anything to do with these things, and as far as I know, isn’t even a commonly used descriptor for them.
If by “easily eroded by acids”, you mean “much less easily than the vast majority of metals, unless the acid in question is specifically nitric acid, which is never found in food or drinks”.
OK… ‘easily enough to be a problem in food containers’. Better?
Also if you have pure metallic copper, it might not much affected by the sort of weak acids in food at room temperature, but bare copper gets oxidised, and that oxide layer reacts or dissolves pretty readily in the presence of things like citric, malic or acetic acids, which are very common in food and drinks. And if it’s the inner coating of a thermos, it’s likely some of the liquids going in there will be hot, which speeds up the rate of reaction. (Edit: also thermos type products are designed for portability, which implies agitation, which would also increase reaction rate. It’s all moot because I think the product we’re discussing doesn’t exist, outside of the scope of woo where people actually want to drink copper compounds for ‘health’).
That’s why the internet is full of ‘cleaning pennies with coke/ketchup/lemon juice/vinegar/etc’, and pure copper pots are explicitly disadvised for cooking acidic foods; copper chefs cookware is usually lined with silver - partly for heat conduction; partly to isolate the copper from the food.
Jumping in on this copper thing…
I would not want copper to be in direct contact with the foodstuff. But if we are talking about a vacuum thermos type system. Would a gold plate on the inner layer of the outer stainless steel double shell be the best thermal reflector? The inner bulb being stainless steel. Then the vacuum space. Then the second stainless steel layer having a gold plate. I recall that gold plate reflects heat best?