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#1 2022-01-10 12:40:56

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,047

Bubble Dome from Molten Material

SpaceNut ... I searched diligently for "bubble" in Topics, and found two by Void that do not cover this specific focus.

Today, as most days, a soap dispenser produced a bubble of liquid soap fluid when I opened the lid.

As I studied the bubble, while thinking about NewMars and it's many topics, I wondered if there were a topic covering the "manufacture" of a dome habitat using material that can stretch into a thin spherical shape as that soap liquid was doing.

Now soap liquid has properties that allow it to perform "magical" feats, such as stretching under air pressure to produce a bubble.

When carried to an extreme, such a bubble can close off and float away as a perfect sphere, subject only to deformation due to temporary air currents.

This topic is dedicated to the proposition that humans living today on Earth, can imagine and formulate a liquid that could be prepared on Mars (or potentially even the Earth) and certainly away from Earth in any vacuum environment, to deliver a spherical shaped habitat able to hold pressure.

I'm looking for serious contributions to this topic, from such members as Calliban, kbd512 or perhaps a member who has actual experience with industrial chemistry. 

To start things off, I'm imagining that molten metal (with the right mix of components) might be able to stretch into a bubble like soap, assisted by gas pressure underneath.

A clue along these lines is provided by Ma Nature.

There are springs at Yellowstone (and other terrestrial locations) where bubbles of gas rise up under liquid/molten material so that the molten material forms a dome until it inevitably pops, because cooling does not happen fast enough.

If one of us humans were to apply an "instant chill" to one of those natural bubbles, the bubble itself might be collected and set on the ground as a demonstration of principle.

I'm looking for someone with ** lots ** of education in the appropriate fields to take an interest in this topic, and (if willing) post about how this might work.

(th)

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#2 2022-01-10 12:47:05

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,047

Re: Bubble Dome from Molten Material

To insure this new topic does not languish without a reply, I will add this from Science Fiction ...

Science Fiction writers (of course) have ** all kinds ** of backgrounds.  What they have in common is a rich imagination and skill with language.

I am remembering a sketch of a proposition that an asteroid might be heated using solar energy until it is a perfect sphere of molten material.  The imaginative writer then described an enterprising protagonist inserting a tube into the center of the hot globe and pushing gas into the center of the hot sphere, so that it inflated into a perfect bubble of molten material.  As the radiation of energy into space proceeded, the exterior of the bubble cooled, and eventually the entire sphere cooled, so a port hole could be cut into the wall.

I am imagining something like that for Mars, except that the spherical shape would be inflated on a flat surface, so that when cooled, the shape would that of a hemisphere on the surface.

(th)

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#3 2022-01-10 13:32:49

Void
Member
Registered: 2011-12-29
Posts: 7,076

Re: Bubble Dome from Molten Material

Perhaps I will remember later, the name.

A book I borrowed from a library, seems to me that someone had scribbled "Platinoid Quackery" on it. smile

This very much was before Gerard K. O'Neil.

Perhaps the book was even a inspiration through the notion that everyone is related to many people through whatever.

I have actually gone into a resting mode, but will make an attempt.

As I recall, the idea was to inflate an asteroid which was melted, with steam or maybe centrifugal force.  Probably not a bad first try, but I am not really sure that it can be within the scope of what humans can do in the next 100 years, or what they would want to do.

I guess rather than working with a ceramic material like rock which will crack as it cools, I would suggest the UK/European proposed method of extracting Oxygen from regolith, using electrolysis in a Calcium Chloride salt bath, and then extracting metals from that, to make a frame, and then perhaps taking the slag and trying to 3D print that into something useful, in that manner we might avoid cracking from shrinking.  At least that could be a hope.

And which those materials perhaps, constructing useful structures.

Just now, the winds of change seem to be changing directions in many ways, without a strong definition of direction.

I would not invest too much in any one thing.  It is sort of a wait and see moment, I think.

Done.

I think that the title may have been "Islands in the Sky" + something else.

Last edited by Void (2022-01-10 13:40:44)


Done.

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#4 2022-01-10 14:35:10

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,047

Re: Bubble Dome from Molten Material

For Void re #2

Thanks very much for your thoughtful contribution to this new topic.

I am picking up on a concern you raised, and I'm hoping you will think about it some more.

You expressed a worry that non-metals might crack when they cool, and I would like to point out that the crust of the Earth is filled with millions if not billions of examples of non-metal forms that were molten, cooled, and did not crack.

It should be possible for any reader of the forum to think of examples of objects in their personal environment that reflect that origin.

At the same time, I recognize that trying to inflate a molten mass (metal or non-metal) into a dome might be challenging.

However, I offer the thought (subject to confirmation) that Ma Nature provides example of that as well, in the form of countless caves that are found in the upper parts of the mantle all over the Earth.

In many of those cases, water has been at work to hollow out volumes that can then be visited by brave humans with a super-sized tolerance for risk.

In the case of an inflated habitat on Mars, the Earth, or anywhere away from Earth, it might be possible to apply similar processes.

In any case, thanks again for giving this new topic a boost!

(th)

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#5 2022-01-10 20:29:39

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 28,832

Re: Bubble Dome from Molten Material

Make really tall tank with removal able sides such that you fill it with a material that when you fire coherent beams to a target it solidifies and what remains is still not such that all you do is finish the shape and let the sides down.

If anything blow a molten ball of glass into the shape you want and let it cool...

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#6 2022-01-10 21:12:27

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,047

Re: Bubble Dome from Molten Material

For SpaceNut re #5

Your suggestion of considering glass is quite interesting (to me for sure)

We have a glass blowing facility in the area, and the practices of glass blowers there look very much like the videos of such work available on the Internet.

The key "construction" technique is to turn the work while pumping air into the bubble, so that it holds the shape you're striving for.

Some thought (and not a little experience) would need to go into creating a mixture of materials that would stretch the way a soap bubble does.

Molten glass sags if it is not rotated as described above.  I would expect the same to be true of molten iron if it were inflated with air the way glass is.

Hopefully this topic will attract some contributions by members who have actual experience with this concept.

However, if there is a non-member forum reader who would like to contribute, please read the Recruiting topic for procedure to request a membership.

Blowing a spherical shape of molten mass would be much easier in space, because only microgravity would be present, and the forces of cohesion and adhesion of the hot material could be expected to greatly exceed the microgravity.

Getting the work product to the surface of Mars would be a challenge.  Perhaps this is an example of a concept that would work best ** in ** space.

Thanks again for the molten glass idea!

Edit later .... thinking about the problem a bit more, and reflecting on the glass blower's technique ....

Perhaps a better model is a potter.  We (humans) are generally aware of the ancient practice of rotating moist clay on a rotating platform to make objects for utility and for storage purposes.

A 3D Printer that works with a rotating bed lays a bead while the bed rotates underneath.  The construction method is similar to that of a potter.

I'm thinking about the molten glass suggestion from spacenut ...  The glass blowers I have watched were working in a horizontal configuration, but I seem to recall seeing the work rotated to the vertical to achieve particular results.

In the case of building a dome on Mars ... if the molten material were rotated on a platform while air is inserted to the center of the mass, an outside "potter" could shape the material with a paddle made of material able to resist the temperatures.

(th)

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#7 2022-01-10 22:10:56

Void
Member
Registered: 2011-12-29
Posts: 7,076

Re: Bubble Dome from Molten Material

I would prefer to let you struggle with development of your imagination.  So, I will not say no, your direction is wrong.
But I would wish to offer some alternate pathways, without the notion that you must drop your other pathways.  I do not what you or others to not try to find a way(s).

Some time ago, as I am really becoming a silver hair, thoughts about the Moon were that for commercial reasons the vacuum of the Moon could be valuable.  Now though, it is likely that a better vacuum can be created elsewhere.  Choose your place.  I think now, the idea would be to allow a thin atmosphere to evolve on the Moon from human activity, because it should be quite easy to build very good vacuum chambers on the Moon.

The same could be true for LEO, and, I think, Mars.

I like your move towards 3D printing.

Vacuum Deposition:
https://www.sciencedirect.com/topics/ma … 20coatings
https://en.wikipedia.org/wiki/Vacuum_deposition

So, that is a path that may work in LEO, the Moon, and Mars.  Sort of a hot method in a vacuum.

I guess a balloon of some fabric or film could be your mold, in LEO.  For the Moon, maybe a very low-pressure balloon with argon in it?  For Mars, you would need a real vacuum chamber of very large size, where you could bring the pressure very down, relative to the ambient of that location on Mars.

A hot process may require annealing, and I would think that having a large enough chamber to put a hot made blown glass or metal object would be quite a task.

A high boss I had at 3M indicated in a fire safety demonstration that at 800 degrees F, half of the energy of an object will leave by radiation.  So, it is huge energy loss, unless in an insulated kiln or annealing chamber.

Perhaps I have that wrong.  Not sure.


I have been thinking about a cold process, using Urea and Perchlorates as feed stock as well as regolith.  For this, Mars seems pretty good.  No, we can divorce this from pee, so the squeamish can settle down.  We use urea for many things already.  Saying "Pee Bricks", makes for newsfeed.  Not needed.

I am interest in this cold process is that I think that fibers can be embedded into the "Paste".  For this a vacuum may not be desired, as we may not want water to evaporate quickly.

Fibers could be organic as in hemp, or basalt fibers, or metal mesh.

I encourage you to continue to think of blown processes, but I hope I might have indicated what problems may exist.

A hot process that I might be interested in would be an aerogel substitute which might be 3D printed.

Just trying to be helpful, not to discourage your efforts to imagination.  I really like that you are working on stuff.

Done.

Last edited by Void (2022-01-10 22:34:04)


Done.

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#8 2022-01-11 07:39:04

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,047

Re: Bubble Dome from Molten Material

For Void re #7 .... thank you for continued encouragement of this new topic.

You have rightly pointed out that this topic starts as a spinoff of your imagination.

It is my intention to try to enlist participants who can translate imagination into real world structures.

The properties of a molten mass must be "just right" to permit "construction" of a large hollow structure by inflating the molten mass with gas.

I am hoping persons with the requisite knowledge and experience will emerge and join the forum to contribute to this topic.

To assist with moving this topic from imagination to real-world achievement, please read the Recruiting topic and apply for membership.

(th)

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