Redneck Space Habitats, Chicken Wire and Melted Beer Bottles

[Geomartian]

In low gravity environments liquids including molten material will form a sphere. If a wire loop (made from a material that the molten material will wet or adhere to) is inserted into that sphere of melt and then slowly withdrawn, it will have a web or blob of molten material captured in the loop.

Conceptually if you pulled a wire matrix (chicken wire) through a large sphere of melt you could create a continuous (if knobby) surface which could become airtight. You could also bend the chicken wire and molten glass into a particular shape before it cooled.

You could also build a chicken wire structure and then slide portable spheres of melt along the surface until you can completely cover/seal the entire structure.

In space you can use electrostatic fields to manipulate molten materials without worrying about contamination from physical contact. You could use electrostatic squeegees to spread the molten material evenly over the chicken wire.

The glass could be formulated to melt at a low temperature (beer bottles?). In space you want to be able to melt the glass under almost any conditions. The glass could be optimized for melting by microwaves or even by direct electrical current. Originally, I used large solar furnaces to produce the melt but that is extremely unwieldy. You want to be able to melt or fuse the glass in small tight spaces.

The chicken wire is a simple robust substrate. If it is done properly any fracture propagation in the glass will be limited to one cell of the chicken wire. This limits the area of damage from micrometeorite strikes. Even if a larger area is fractured the chicken wire will still give some cohesion to the pieces. Areas of fracture might be repaired by filling it in with glass putty, melting it with microwaves, then shaping it with electrostatic squeegees. (A space suit with chain mail might keep you from getting fried by reflected microwaves).

The chicken wire would be optimized for wetting by a particular molten material. This could be some very expensive chicken wire. Depending on the temperature of the molten material (including molten native metals) platinum and other very high temperature materials as found in asteroids might be used to make the chicken wire.

Start with a spool of wire and using a horrible looking spider robot convert that spool of wire into a structural shell. Add some molten glass to the wire shell and you have a (potentially) air tight hard shell structure. Most people would like the hard-shell structures over the inflatable ones.



If an asteroid is close enough to the Sun a solar furnace can be orbited over the asteroid being mined. An orbital mirror can be kept aimed at the sun while a mirror on the surface of a rotating or spinning asteroid is more complex. Because of the low gravitational forces, catapults or slings are sufficient to move materials between the furnace and the asteroid.

The mirror could use volatiles released by the heating for station keeping. I originally had the mirror throwing rocks as reaction mass except that really screws up the local space environment. Asteroid mining should not be scattering material around that will later become navigation hazards.

This is an improved version of parts of a paper that I gave to the Space Resources Roundtable.

Colorado School of Mines, Golden, Colorado (2001)

 

[YetAnotherBob]

I've seen this proposed since the 1970's. I have yet to see anybody try it out. I wonder if it will work as you suppose. Generally there are problems that pop up when one tries some theoretical process. But those problems often lead to more processes.

So who will try it? NASA or Roscosmos? Probably not. It's the sort of thing you do when you have materials and time. The crews on ISS have neither.

 

[Geomartian]

The biggest problem I see is getting the structure to pressurize without fracturing. If a strong balloon were inflated on the inside you might carefully soften the structure while increasing the balloons air pressure. Once the structure has been annealed (fractures and microfractures removed) at its operating pressure and the stresses distributed to the wires (and not the glass between the wires) it should be quite strong. You might slightly overpressure the balloon to give it some contracting tension to the wires and glass in the structure.

Deflate the balloon or just leave it in place as another layer of vacuum protection.

I used the beer bottles as an exaggeration. It could be any material that direct sunlight (100 C at the Distance of Earth) could not melt while a microwave wand could soften or melt.

It might be anything that you can both apply and then remove the stresses from after inflating the structure. Some glasses could be manufactured with these properties and I am pretty sure that glass would be a lot more expensive than the glass used in beer bottles.

 

[YetAnotherBob]

"

The biggest problem I see is getting the structure to pressurize without fracturing. If a strong balloon were inflated on the inside you might carefully soften the structure while increasing the balloons air pressure. Once the structure has been annealed (fractures and microfractures removed) at its operating pressure and the stresses distributed to the wires (and not the glass between the wires) it should be quite strong. You might slightly overpressure the balloon to give it some contracting tension to the wires and glass in the structure.

Deflate the balloon or just leave it in place as another layer of vacuum protection.

I used the beer bottles as an exaggeration. It could be any material that direct sunlight (100 C at the Distance of Earth) could not melt while a microwave wand could soften or melt."

GK O'Neil proposed just setting up big mirrors and then spinning the asteroid at the focus. Then just wait. When the object gets hot enough, the metals will melt on the surface, and any water or other volatiles inside will boil to provide the pressure.

Who knows, it might even work.

More likely though, the interior pressure would expand the bubble of molten steel until it burst.

 

[Catastrophe]

Can that be made for mercury which we have as liquid now?

 

[YetAnotherBob]

T

Can that be made for mercury which we have as liquid now?

That would require that you refine it all first. The original idea was that if you pick the proper asteroid, you don't need to do that, just heat it and then let it cool. In a week you've made a large iron/steel habitat.

But the real question remains, will it work?

 

[Geomartian]

Shown here is an organic 3D printer. (Circa 1961)

The problem that the redneck space habitat was intended to solve was reducing the cost of launching a prebuilt habitat from Earth. The physical size of a habitat module makes it expensive to get into orbit.

At some point we will need actual experience in manufacturing structures in space. Being able to make a solid air-tight surface (of any size) would be a good start.

In its simplest form a Redneck Habitat would require a big spool of wire and a dozen bags (or tubes) of glass or low melt paste. (A guess) For a sphere 3 to 4 meters in diameter the spool of wire might weigh 50-100 kg while the glass paste might weigh 600 kg.

A sophisticated robot (space spider which could never possibly go berserk) could turn the spool of wire into a space structure or framework. The spider can then fill in the wire framework with the paste. I lean toward a paste that can be heated and melted by microwaves. The wire and the melted glass would adhere (wet) to each other so the glass would not just melt, ball up, and then drift off into space.

If the glass were moderately transparent it might make a good greenhouse and a quiet space cut off from the noisy environment of the ISS. The hatch (or airlock) and ISS bulk head connector could be sent up preassembled from Earth (or scavenged from a retired module).



Unprocessed asteroid material makes good radiation shielding but does require extensive processing before being usable for fabricating air tight structures.

Tunneling into a highly fractured and non-homogenous asteroid for radiation/meteorite shielding could be a recipe for disaster. You could build two concentric wire frame structures and then fill in the space between them with asteroid regolith. It is faster and easier to build a wire frame igloo to shape and contain the regolith material than it is to blast or tunnel into an asteroid.

 

[Catastrophe]

"The wire and the melted glass would adhere (wet) to each other£

You know this as fact? If not, I know how to accomplish it.

Cat

 

[Geomartian]

The wire would have a surface treatment to make sure that particular glass mix would wet to it. The wire could be treated in a reactive gas (perfectly clean and without surface oxidation) then stored under argon until the seal is broken in vacuum. This wire would probably cost hundreds of times more than regular chicken wire. The economics of orbiting material would more than justify the extra cost.

The other reason for using something like a glass rather than an epoxy is that when that module is scrapped that glass can be stripped off and reused.

Save all of that valuable launch capacity for chocolate!

 

[YetAnotherBob]

Save all of that valuable launch capacity for chocolate!

Chocolate grows on cocoa trees, not coca trees though. You just need a few trees and in ten to twenty years you have all the chocolate you want. No, save the launch capacity for people. People are the real bottleneck.

But Mr. Catastrophe was I think referring to the twin problems of materials science, both material mixing and ultimate strength of the material.

With any material, you have a problem with mixing. Wetting is a part of that. Does the material you wish to use mix well or wet well with whatever you are using as a matrix? If so, they you have two other potential problems.

One is that the materials will combine somewhat and produce a third material with different properties than either of the two parent materials.

The other is that if they don't wet, then with application of force, they may just separate. Think of a tire on the freeway. Separation isn't always a gentle thing.

The force on a large habitation isn't trivial either. Pounds per square inch equates to meganewtons per square meter after all.

So this really hinges on some careful and detailed engineering.

If memory serves me well, I suspect that Mr. Cat is actually the kind of engineer you need for things like this, so listen to him well.

There is a reason the ISS isn't made of Easy Cheese!

 

[Catastrophe]

YetAnother Bob

"But Mr. Catastrophe was I think referring to the twin problems of materials science, both material mixing and ultimate strength of the material."

Correct. My day job was wetting agents / surface active agents.

I would guess a silicon surfactant (such as already exists) would adhere to metal (as already commonly happens in corrosion inhibitors) leaving a silica (instead of the normal hydrocarbon) tail which would be compatible with the glass.

You could read my book on related subjects (but I can't tell you any details )

 

[Geomartian]

I could have been an engineer if they had found the drain bamage early enough. Now I am just a 2% inspiration man and leave the other 98% to the less cunning.

 

[SpaceShuttleer]

This is a good discussion, and after reading I don't think I can add much. I noticed above someone said that this would be preferable to Expandable Habitats such as the Bigelow B330 and I can see them as better, being they can be built in space and not require an expensive launch. But I think for now, Expandable Modules will be very useful, as this kind of technology is not even being tested right now and will probably take a lot longer to perfect to the state at which it would be safe enough to use with people.

 

[Geomartian]

The spider has been around a while.

Incredible Technology: Spiderlike Robots Could Build Giant Space Structures

Humanity could soon be building huge structures in space, one piece at a time — the way spiders spin their webs here on Earth.

www.space.com