settling in craters - roofed by geodesic sphere

lmvdr · 2004-01-06 11:39:24

hey,

what do you think about the following idea:

a crater with a diameter around 50-200 meters gets roofed by a flat geodesic sphere construction, which gets packed by a stable but thin membran. (exept the very top of the construction.) now a excavator gets into the construction and makes it as deep as needed. the excavated ground gets crushed and filled outside on the geodesic sphere. (perhaps 1 or 2 meters thick.)

the inside of the crater can now be designed as needed. the hole on the top of the construction could be wrapped by translucent material. possible functions of the construction are:
- housing
- factories
- power plants
- farms and plantages
- scientific purposes

these are the benefits:
- roofed craters are better armed against sand stormes etc. then conventional "buildings"
- the mostly used construction material (the ground to isolate the roof) lies everywhere around and doesn't need to be factured and transported over wide distances
- the surface of the building (to the outside, not to the ground) is minimal to its volume. so the the efforts to hold the inside air pressure are also minimal.

of course this idea is very theoretical and utopic, but lets discuss it!

greetings
lmvdr

Rxke · 2004-01-06 12:45:20

Hi, lmvdr!

Don't get upset if people don't answer quickly, everybody's a *bit* excited about the rovers right now...

What do you mean with 'flat geodesic sphere' ? Is that a certain 'angle'?

lmvdr · 2004-01-06 13:33:09

hey rxke,
since i don't plan to settle on mars during this week, it's okay when discussion starts at a low frequence... :;):

i am not a native speaker (as you), so please excuse me when my thoughts sound a bit confusing.

with "flat geodesic sphere" i mean a very low height, so that it is very flat.

this sketch of a section through the crater should help you to imagine my idea...

thanx
lmvdr

Rxke · 2004-01-06 14:10:05

Neat... Like the way the dome follows the crater curvature, what are the stress/pressure advantages (or drawbacks) in such a design? Reminds me of a bridge, but in this case you'd have mainly upward (air) pressure, how's the distribution of the added regolith (ground) on the dome?

I already like it, because it looks good, aestethics are important if you want to settle somewhere for the rest of your life...

Read your profile, BTW. Looks like another interesting member has arrived! I'm sure you'll bring in some good idea's.

lmvdr · 2004-01-06 14:35:02

rxke,

thank you for your answer. the masses of ground and stones on the roof should prevent it from lifting. a geodesic dome resists pressure from outside as well as pressure from inside.

i will precise this idea tonight a bit.

greetings from southern germany
lmvdr

Hazer · 2004-01-08 00:17:22

Speaking of those crater settlements...
Why not insulate the interior with aerogel to prevent heat loss during the Martian Night?
Almost like a rigid tent buried in snow...

Shaun Barrett · 2004-01-08 05:52:33

To fully counteract the upward pressure of even a 350 millibar atmosphere inside your domed crater, Imvdr, you will need about 3.6 tonnes of regolith on each square metre of your dome.

Rxke · 2004-01-08 06:29:51

Wich sounds a lot, but guesstimating from the drawings, they're still workable ( diameter of crater about 100-150 m, thickness dome about 5 meter...)

if you put 'too' much regolith on the dome, pressure just gets translated sideways, keeping the structure stable, as long as the walls of the craterrim are strong enough...

still like it better than the )?( inverted domes, where all the pressure comes together on a 'top ring' (ASCII is no good, the things i had in mind look a bit like broad cooling towers...

lmvdr · 2004-01-08 11:28:49

the shape of the cooling tower seems to be absurd when one remarks that buildings on mars tend to explode (insead of imploding like on earth).

to keep on the comparision to cooling tower: the buildings around nuclear power plants are usually mirrored U shape. this is the best shape for absorbing outer forces and for keeping it stable in case of a pressure inside.

i think this result from the ratio of volume to surface, which is highest for domes.

and as you mentioned: by lowering them into earth, the horizontal forces (resulting of the transformed vertical forces) get "eaten" by the surrounding ground.

i don't expect this construction as the perfect housing, but it would be cool for factorys and power plants. (they won't need daylight, which should be available for housings.)

regards,
christoph

lmvdr · 2004-01-08 11:49:27

sorry shaun & hazer,

i haven't read your message before writing the other one.

the 3.6 tonnes/m2 are not only caught by the regolith on the top but also by the construction of the geodesic dome. together they should keep the building in crater.

hazer, i don't know exactly what you mean with aerogel, but it sounds very expensive. why not pouring so much regolith on the building until it insulated well enough? there is enough regolith on mars to insulate the whole planet...

if the buidlings would be placed (for what reason ever) near the frosty poles, we could additionally powder them with some meters of snow, what would even increase the insulation.

see, there are enough holes on mars, so we don't need to dig new ones. and life on mars will be a life in caves. either surrounded by lithium-teflon-aerogel-whatever or regolith and a layer of cheap plastic.

note: usually i engaged in lightweight construction, but it seems to me that here are enough which fancy this type. so i just try to diversify the discussion a bit.

regards,
christoph

Rxke · 2004-01-08 12:27:24

to make double sure, i was just referring to plans i saw, it's not exactly cooling tower-shaped, the base is much broader, something like this (badly drawn, sorry...) the inward curvature is to resist the higher inside pressure, but of course this results in needing an 'upper-ring' that has to deal with all the forces (and a strong base) The two arrows is to point out the force from inside...

I like your idea much better.

The one in the pic would be above the ground, so more exposure, and maybe easier to build out of concrete, but still... You'd have more problems with isolation etc... Your idea would be simple to isolate/radiation-proof: just add regolith...

Hazer · 2004-01-08 22:08:33

Aerogel just happens to be the world's lightest solid and one of the best insulators availible. I thought that aerogel insulation would be something that a Mars settlement could really use.
I like the idea of settling in craters.

Shaun Barrett · 2004-01-09 06:46:39

As long as you create enclosures built to withstand the air pressure inside, you can use any design you like.
For what it's worth, I like the idea of clear domes which go right down to ground level so you can walk up to the dome material and look out onto the rusty plains (dotted with genetically engineered plants helping to terraform our new home! ).
Yeah, yeah ... O.K. .. so I'm a Green!! :laugh:

Cristoph! I'm not sure if you're aware that we've had discussions about enclosures on Mars over at "Life Support Systems", under the headings:-
1) "Canyon habitats"
2) "We need a brainstorming session!" and
3) "Domed habitats".
Your idea is unique in that it involves a geodesic dome + regolith rather than transparent material. It sounds more robust, mechanically easier to achieve, and should provide ample radiation protection, so it may become the method of choice for those reasons.
But for me, probably because I was brought up on a diet of fictional martian cities under clear domes, I prefer the open 'feel' of such designs.

lmvdr · 2004-01-10 08:13:39

shaun,

of course it would be cool to live unter a transarent dome. i will have a look at the threads you mentioned.

regards,
christoph

Rxke · 2004-01-21 02:11:10

lmvdr, Hazer,...

About the Aerogel: it sure is expensive:
[http://www.mkt-intl.com/aerogels/aerogel_order.html]As this supplier proves...

Gennaro · 2004-01-21 16:38:48

A wonderful idea! Think about the space you'll gain for a limited amount of construction material and excavation work.

Guess the materials would be the same ultraviolet resistant plastics that would be used for the usual ground domes.

The heavier the anchoring, the less regolith needs to be put upon the roof and the larger the sunlit area. Would it perhaps be an economical way for housing large scale pressurized agriculture? A crater-wide wheat-field?

What about using corinthian columns for ground anchoring additional central support of an extra wide crater dome? Imagine the atrium-like or open art noveau framework rosetta windows that could be designed!

Neo-gothic, anyone?

Shaun Barrett · 2004-01-22 19:32:30

Just out of curiosity, I had a look at some numbers regarding martian regolith and how much of it might be necessary on the roof of this proposed geodesic dome. (I had to assume that martian sand and earthly sand aren't radically different in density.)
Naturally, I don't know how much of the force needed to constrain the internal air pressure will be provided by the strength and weight of the dome structure itself and its foundations.
Just for the sake of argument, I've assumed all of the constraint is to be provided by the weight of regolith. In fact, of course, some will be provided by the mass and strength of the dome materials, though this will be a relatively minor contribution. And there will need to be a safety factor built in, which means relying less on structural strength and more on dead weight. So I don't think my final figure is going to be too far wrong.

I did a quick google and found that "dense dry sand, poorly graded" has an average density of 0.06 lbs/cu.in (must have been an American source! )
A quick calculation converted that into a metric value of 1660 kg/cu.m

But on Mars with its 0.38g surface gravity, the same cubic metre of similar material will have an effective weight of only 630 kg/cu.m
In order to fully oppose the 3600 kg/sq.m of pressure in a dome with a 350 millibar atmosphere, you would need 3600/630 metres of material or approximately 5.7 metres of regolith (assuming it is roughly the same material as terrestrial "dense dry sand, poorly graded" of course! )

For our U.S. cousins, that translates to about 19 feet of regolith on top of the dome.
That's a lot of dirt to move, but it looks 'doable'.

lmvdr · 2004-01-22 21:56:56

hmm, 5.7 metres is really much. since martian regolith seems to consist at large parts of iron (with a density of 7000-8000 kg/m3), i hope it is more dense than common sand on earth.

my inital idea was to put the regolith which was digged out of the crater on the top of the dome (through a hole on the very top which gets closed with some transluzent material later).

does anybody have a section through a "standard crater" on mars? i am interested on the ratio of diameter to depth.

i think that we really need some excavators first on mars. we have to remove all those stones in order to place some prefabricated buildings, we have to dig some regolith in order to extract the iron dust, we have to dig some ditches in order to build underground pipelines. and so on and so on.

greetings from germany
lmvdr

dickbill · 2004-02-03 09:17:55

A short description of what intendeded to be Biosphere-II :

J Aerosp Eng. 1991 Jan;4(1):23-30. Related Articles, Links

Biosphere II: engineering of manned, closed ecological systems.
Dempster WF.
Sarbid Ltd. and Space Biospheres Ventures, Oracle, AZ 85623, USA.
Space Biospheres and Ventures, a private, for-profit firm, has undertaken a major research and development project in the study of biospheres, with the objective of creating and producing biospheres. Biosphere II-scheduled for completion in March 1991-will be essentially isolated from the existing biosphere by a closed structure, composed of components derived from the existing biosphere. Like the biosphere of the Earth, Biosphere II will be essentially closed to exchanges of material or living organisms with the surrounding environment and open to energy and information exchanges. Also, like the biosphere of the Earth, Biosphere II will contain five kingdoms of life, a variety of ecosystems, plus humankind, culture, and technics. The system is designed to be complex, stable and evolving throughout its intended 100-year lifespan, rather than static. Biosphere II will cover approximately 1.3 hectare and contain 200,000 m3 in volume, with seven major biomes: tropical rainforest, tropical savannah, marsh, marine, desert, intensive agriculture, and human habitat. An interdisciplinary team of leading scientific, ecological, management, architectural, and engineering consultants have been contracted by Space Biospheres Ventures for the project. Potential applications for biospheric systems include scientific and ecological management research, refuges for endangered species, and life habitats for manned stations on spacecraft or other planets.

Visited by Moderator 2022/03/08

dickbill · 2004-02-03 09:26:45

And one of the consequences of living in such biodomes :

Proc Natl Acad Sci U S A. 1992 Dec 1;89(23):11533-7. Related Articles, Links

The calorically restricted low-fat nutrient-dense diet in Biosphere 2 significantly lowers blood glucose, total leukocyte count, cholesterol, and blood pressure in humans.
Walford RL, Harris SB, Gunion MW.
Space Biospheres Ventures, Oracle, AZ 85623.
Biosphere 2 is a 3.15-acre space containing an ecosystem that is energetically open (sunlight, electric power, and heat) but materially closed, with air, water, and organic material being recycled. Since September 1991, eight subjects (four women and four men) have been sealed inside, living on food crops grown within. Their diet, low in calories (average, 1780 kcal/day; 1 kcal = 4.184 kJ), low in fat (10% of calories), and nutrient-dense, conforms to that which in numerous animal experiments has promoted health, retarded aging, and extended maximum life span. We report here medical data on the eight subjects, comparing preclosure data with data through 6 months of closure. Significant changes included: (i) weight, 74 to 62 kg (men) and 61 to 54 kg (women); (ii) mean systolic/diastolic blood pressure (eight subjects), 109/74 to 89/58 mmHg (1 mmHg = 133 Pa); (iii) total serum cholesterol, from 191 +/- 11 to 123 +/- 9 mg/dl (mean +/- SD; 36% mean reduction), and high density lipoprotein, from 62 +/- 8 to 38 +/- 5 (risk ratio unchanged); (iv) triglyceride, 139 to 96 mg/dl (men) and 78 to 114 mg/dl (women); (v) fasting glucose, 92 to 74 mg/dl; (vi) leukocyte count, 6.7 to 4.7 x 10(9) cells per liter. We conclude that drastic reductions in cholesterol and blood pressure may be instituted in normal individuals in Western countries by application of a carefully chosen diet and that a low-calorie nutrient-dense regime shows physiologic features in humans similar to those in other animal species.

did they include the pizzas secretely ordered ?

Visited by Moderator 2022/03/08

dickbill · 2004-02-05 16:19:41

Not much time, but I googled a little bit on Mt Everest.
Altitude about 8850. Average temperature is -37 Centigrade, goes as far as -60 C (-100 F said unother source ).
Pressure is 300 mb, one third of the atmospheric pressure.

isn't it close to Mars equatorial temperature ?
By setting a pressurized biodome at 1 atmosphere on top of a 8K summit, the dome would have a 600 mb positive pressure, a good exercise to practice on MArs. By the way, a 600 mb biodome in Mars 7-10 mb atmosphere would have to fight about the same positive pressure.

For the UV radiation on Mt Evererest, I found nothing , but, here again, it's surely high enough on Everest to constitute a good martian testbed. For other radiations on the Everest, cosmic, solar etc, I also found nothing. Too bad.

So, a pressurized biodome/greenhouse (small of course) with a couple of nice plants on top of a 8K summit , who is with me ?

not Juda, of course....

clark · 2004-02-05 16:25:14

:laugh:

You're wonderful dickbill.

Of course the moon might make a better test bed for Mars than Mt. Everest, but I could be wrong.

Bill White · 2004-02-05 16:35:53

Not much time, but I googled a little bit on Mt Everest.
Altitude about 8850. Average temperature is -37 Centigrade, goes as far as -60 C (-100 F said unother source ).
Pressure is 300 mb, one third of the atmospheric pressure.
isn't it close to Mars equatorial temperature ?
By setting a pressurized biodome at 1 atmosphere on top of a 8K summit, the dome would have a 600 mb positive pressure, a good exercise to practice on MArs. By the way, a 600 mb biodome in Mars 7-10 mb atmosphere would have to fight about the same positive pressure.
For the UV radiation on Mt Evererest, I found nothing , but, here again, it's surely high enough on Everest to constitute a good martian testbed. For other radiations on the Everest, cosmic, solar etc, I also found nothing. Too bad.
So, a pressurized biodome/greenhouse (small of course) with a couple of nice plants on top of a 8K summit , who is with me ?
not Juda, of course....

Several years ago, on a pre-NewMars discussion board some of us discussed alpine "hotels" built on the tops of tall mountains equipped with full CELSS and accessed by dirgibles with pressurized cabins that connected to the hotel via airlock.

Cheaper than the moon and easier to get tourists to and from.

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#1 2004-01-06 11:39:24

Re: settling in craters - roofed by geodesic sphere

#2 2004-01-06 12:45:20

Re: settling in craters - roofed by geodesic sphere

#3 2004-01-06 13:33:09

Re: settling in craters - roofed by geodesic sphere

#4 2004-01-06 14:10:05

Re: settling in craters - roofed by geodesic sphere

#5 2004-01-06 14:35:02

Re: settling in craters - roofed by geodesic sphere

#6 2004-01-08 00:17:22

Re: settling in craters - roofed by geodesic sphere

#7 2004-01-08 05:52:33

Re: settling in craters - roofed by geodesic sphere

#8 2004-01-08 06:29:51

Re: settling in craters - roofed by geodesic sphere

#9 2004-01-08 11:28:49

Re: settling in craters - roofed by geodesic sphere

#10 2004-01-08 11:49:27

Re: settling in craters - roofed by geodesic sphere

#11 2004-01-08 12:27:24

Re: settling in craters - roofed by geodesic sphere

#12 2004-01-08 22:08:33

Re: settling in craters - roofed by geodesic sphere

#13 2004-01-09 06:46:39

Re: settling in craters - roofed by geodesic sphere

#14 2004-01-10 08:13:39

Re: settling in craters - roofed by geodesic sphere

#15 2004-01-21 02:11:10

Re: settling in craters - roofed by geodesic sphere

#16 2004-01-21 16:38:48

Re: settling in craters - roofed by geodesic sphere

#17 2004-01-22 19:32:30

Re: settling in craters - roofed by geodesic sphere

#18 2004-01-22 21:56:56

Re: settling in craters - roofed by geodesic sphere

#19 2004-02-03 09:17:55

Re: settling in craters - roofed by geodesic sphere

#20 2004-02-03 09:26:45

Re: settling in craters - roofed by geodesic sphere

#21 2004-02-05 16:19:41

Re: settling in craters - roofed by geodesic sphere

#22 2004-02-05 16:25:14

Re: settling in craters - roofed by geodesic sphere

#23 2004-02-05 16:35:53

Re: settling in craters - roofed by geodesic sphere

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