/sci/ - Science & Math

>>10948916
We can not build it. You are asking how much it would cost to with 18th century technology to go to the moon. All the money in the world can not buy it. First of all it will cost you time. It may take a century or more to reach this level of technology. All we can do now is to keep spending money for science and research.

>>10948916
1 trillion United States Dollars

>>10948916
O'Neill cylinders were among the first designs for a space colony, and the most famous, but we have moved on from there and modern space station designs are different. See Kalpana One for how current thinking goes.

https://settlement.arc.nasa.gov/Kalpana/KalpanaOne.html

Main changes are using a short and fat cylinder because such shape is ineherently rotationally stable (does not tend to tumble over as long cylinders do). And placing the colony in equatorial low Earth orbit, where radiation environment is almost Earth-like. This means you save on millions of tons of shielding, a huge benefit.

>>10948957
That seems like it's be a lot more cramped and no sunlight at all for the inhabitants

>>10948975
It is smaller than an O'Neill cylinder and without huge glass walls, because it aims to be an actually realistic design.

>>10948916
>>eventually the yield of resources produced would outweigh the cost
what fucking resources?

>>10949106
You could grow food and farm livestock on them

>>10948916
What resources would they be able to produce?

>>10948943
>Sealed metal cylinder spinning around really fast in space

Waah, too advanced. Humanity will never be able to build such a marvel.

>>10949309
Yeah also filling it with dirt and rocks is hard

>>10949348
Holy shit, where will we ever find dirt and rocks in space? Humanity is trapped on earth forever.

>>10949309
we can shot tiny tin cans into orbit, that's it,
even this is often failing and almost breaking the bank,
there is no way we could launch such a huge structure into space, we can not launch enough material into space, we can not construct such a structure it's much bigger then everything we ever build, we got not enough energy, we don't know how to make such a structure work, we can not supply it with the wast amounts of water it needs, etc.

>>10949385
>We can shot tiny tin cans into orbit, that's it
Space Elevator or Mass Driver.

>This almost breaks the bank
Not an issue in this scenario

>There is no way we could launch such a huge structure into space
Launch small pieces into space and assemble it on-site

>We cannot launch enough material into space
It would be easier to catch an asteroid for materials anyways

>We got not enough energy
Solar panels and if that's not enough, nuclear fission should work

>We don't know how to make such a structure work
Have you ever bought a can of soda? Humans make cylinders just fine

>We cannot supply it with the vast amounts of water it needs
Catch a comet or something

>>10949385
Oh boy using the commerical space industry it sure is hard to put sheets of metal into space

>>10949482
Actually I was just thinking of the water scenario. Since it's incredibly unlikely we're going to stop the sea level from rising why not drain the oceans a tiny bit and use that water on the space stations

>>10949482
>orbital elevator or mass driver
So we wait for impractical teleportation tier memes instead of just using rockets to do it. Great.

>>10949482
>Space Elevator or Mass Driver.
we got no space elevator and no mass driver and no technology to build this shit

>It would be easier to catch an asteroid for materials anyways

we got no technology to catch asteroids

>nuclear fission
our fission reactors are large, heavy and need lot's of water for cooling
> Humans make cylinders just fine
small cylinders, we can not build cylinders a mile in diameter and certainly not in orbit.
>Catch a comet or something
we lack tech to catch comets

almost every technology we need to build such a structure in space this does not exist yet

>>10949535
How are orbital elevators and mass drivers impractical compared to their benefits?

>>10949385
>we can shot tiny tin cans into orbit, that's it,

Mature reusable rocketry will enable putting thousands of tons into orbit every year. Not sure about an O'Neill cylinder, but we can surely do much better than the ISS.

>>10949564
>expensive
>impossibly difficult
>require arcane materials
>severe drawbacks for each mitigating much of the magical promises

And you still need rockets.

>>10948916
>What would be the cost of making a said space habitats with today's technology?
Motivation to spend money on something with zero initial return on the investment. The people who would benefit from the technology would be no less than 2 generations away. Investors would never get their money back from it. Due to that, no one with actual money spends money on shit like this. There's no technological hurdle preventing us from doing this. It is all sociopolitical-financial.

Your best bet is to remove the space treaty and have the government/military subsidize everything. That's really the only way to kick people in to action. Get there and claim space before the Chinese.

>>10948975
>sunlight at all for the inhabitants
You can't have sunlight in space without atmosphere and magnetosphere to filter it. This is because we do not have glass that can stop enough of the correct radiation to be able to allow windows for normal constant viewing. This is why the cupola on the ISS is the highest cosmic radiation spot of the entire station. On a space station, you will live like you are underground. No sunlight and only artificial lights.

>>10949482
>>10949564
>[earth-based] Space Elevator
Complete sci-fi in all regards.

>Mass Driver
Commercially viable only when reaction mass becomes too costly. Which will never happen since you can make rocket fuel using feces and plant matter.

>>10949735
Multiplayer layers of UV protected glass and water would dampen cosmic radiation

>>10949735
>Space elevator is too sci-fi

Literally the only thing stopping it from happening is material needed for the cable which we're working on

>>10949794
Physics will not allow that to happen. You are in the territory of overunity.

>>10949787
You need several tons per square meter of shielding to shield galactic cosmic rays. So think of a window that is several meters thick.

The only possible exception is in equatorial low Earth orbit, where mere hundreds of kilograms per square meter may be enough.

>>10949787
Good luck seeing anything at all, if you have enough window thickness to make a permanent window something safe in space.

>>10949813
>pic
That is also only at 600km altitude where it is still shielded by the magnetosphere. A colony station couldn't exist there. Only small labs and such could realistically do that of course. Thus, any other higher orbit which would be good for larger structures will be hit with far more radiation and require much thicker shielding for any permanent population.

>>10948916
>cylinder
NO! It must be a torus. Why? The t-handle experiment. Look it up on youtube. Your citizens would be battered to pulp every time the thing decided to flip.

>>10949813
I don't really see the problem with extra thick glass mixed with layers of water

>>10948957
>colony in equatorial low Earth orbit
The stationkeeping requirements for that are onerous.

>>10949965
The problem is getting the mass into orbit. I was looking into this awhile ago and decided that the rotating torus could be contained within a larger stationary torus filled with water 2m deep.

This zero g sea could support living sea creatures like fish and lobsters.

>>10950369
Would it be easier to ship up the sand for the glass or the glass itself?

>>10950655
Why are you using glass? Glass provided quite poor shielding against radiation.

A broader answer regarding mass in general though can be given thusly. We need to begin manufacturing on a lower mass body than the earth for anything shielded to be built.

>>10950670
Having windows is a much better idea for habitation then just having steel walls and an LED light. It's like living in a mind shaft as apposed to an actual colony

>>10950687
There are better shielding materials than glass which are still transparent. I doubt windows would make for a pleasant viewing experience when the habitat is spinning constantly even at only 1rpm.

I expect the real solution is to just shield everything and pipe natural sunlight into the interior. If you want a window you can put a 12k screen on the wall and switch to one of the streaming public telescopes of which I am sure there will be many. Or you can look out the window and down onto the interior of the habitat with the resplendent gardens laid out before you.

>>10948916
One realistic approach would be to carve inside a trojan asteroid at Jupiter's L4 or L5 to use it as a structure and have a thousand drones working 24/7 3D print a layer of yet-to-be-invented void resistant material. Then, also use a ridiculous number of disposable ion thrusters to slowly build momentum.

To make this happens, you would need to

1/Have a space industry sustainable enough for sending men and material into space. That means completly mastering the cis-lunar region with a rich Lunar industry. Aluminium mines to build the biggest part of the rocket (tanks), Ice mines to create the heaviest component of a rocket (fuel) and industry advanced enough to build all the other electric component from redirected asteroid with REE. Maybe have a Moon based space elevator or slingshot to reduce the costs of fret.

2/Have a colonial outpost close enough of L4 and L5 to help the workers. You can't just send worker on a long term mission in deep space without their family and it would be too expansive to have recurrent Earth-L4-L5 trips. So, I suggest having the same settlement as the Moon but on Mars which is closer to L4 and L5 and maybe use Phobos as an operation center.

3/Have a fleet of drones using asteroid dust to 3D-print the habitacle layer inside the asteroid. And this will takes ages. You can justify the Moon Village as a miner outpost to secure redirected asteroids with REE. You can even push for a small Martian resort. And this will be what you have to solve to see your O'neill Cylinder.

Why build an O'neill Cylinder?

I have some fantasy justifications.
-You may want to secure the trojans asteroids. Because redirecting them is hazardous and a 100 quadrillions dollars asteroid worth of gold can be hijacked by space pirates on its way to the Moon.
-You are preparing for a mission to Jupiter and the Jovian system. There are plenty of reasons to go their, ressources of course. Chemicals and gas you can't find on Mars, water in abundance too.

>>10949965
>>10950369
>>10950655
>>10950670
>>10950687
>>10950789
Oh for fuck sake. You guys really don't understand how much the ISS is shielded from cosmic radiation via the magnetosphere. To have something sufficiently thick enough to block long exposure detrimental radiation is to have something that isn't going to work as a window. The equivalent light that did make it through would be about on par with moonlight that we get on Earth. That might be good as a night light, but the added massive required for transparency isn't even worth it. you'd have this station with "thin" walls and monstrously thick windows that stick way out past the wall thickness.

I really wish is wasn't like that. I'd love to have space stations with permanently viewable windows that wouldn't give you cancer in a month or less. I mean how cool would that be? But, we are going to end up with what amounts to as caves in space coated in shielding and solar panels.

>>10952370
>added mass* required
fixed

>>10952370
>>10952375
We could just use giant TV screens fixed to cameras on the outside as windows. If there's no way to see outside except for small viewing areas I just can't see anyone wanting to move to a space station as a permanent home

>>10952782
Yeah, that would be the best solution. The ISS has the cupola that allows people to view the outside for short amounts of time. The same can be done for a space station, but you'd really need to restrict access to ensure yearly exposure does get too high.

>>10952370
>The equivalent light that did make it through would be about on par with moonlight that we get on Earth.

And, "The ratio of brightness of the sun versus the moon amounts to a difference of 398,110 to 1." So, you'd be able to see the sun, like it were the moon, but you more than likely wouldn't see any other stars or the moon itself.

>>10952370
Maybe we are concerned about different types of radiation. Two meters of water was sufficient for my concerns last time I actually researched shielding.

Do you have any references available to show how dangerous and prolific cosmic radiation is? I will look into it myself but I am always looking for opportunities to be lazy.

However I do agree that these structures will be windowless. Natural light can be piped in. A sharp curve in the pipe will heavier particles.

>>10952782
You would have a window in your apartment which would look out over the habitats interior. Not out into the void of space. Unless you went to a special viewing platform.

>>10953556
>Maybe we are concerned about different types of radiation.
Secondary particles(aka "secondary radiation") are the main concern when shielding is involved. In some cases no shielding is preferred over shielding because of the secondary particles being created as the radiation hits the shielding.

You need to remember that shielding isn't a blocker. Shielding is an attenuator at best. The goal is to get the levels down low enough so that it won't cause health probems, but it can't be totally blocked. Which is why NASA is continually working on shielding with higher hydrogen molecule density. The best shielding would be hydrogen metal, if such a thing could exist as shielding. lol

https://en.wikipedia.org/wiki/Cosmic_ray

>>10949211
that would be ORDERS OF MAGNITUDE more expensive than food or livestock grown on earth. Second if you're growing food for export you have an open system, meaning you need to continuously import mass which is a going to be a HUGE cost. Growing food is quite possibly the dumbest thing you could do with a space colony.
>>10949946
you're a fucking idiot. Tennis racket theorem only applies to objects with three distinct principal moments of inertia

>>10953761
No, you're a fucking idiot for not taking into account the expense of getting foodstuffs into orbit. Take your meds.

You are probably right about the t-handle though. I am not a physicist.

>>10953761
The point of space colonization is not that it's cheaper, it's that it could infinitely expanded upon again and again since resources/space are virtually limitless. Literally all the land on Earth is already claimed by someone and there is only so much efficiency you can achieve before you hit hard limits. Beyond that, there is simply alot of political baggage you need to circumvent to do things on Earth. Once initial costs are complete, the political navigation to build something new will likely be much less than on Earth, which is arguably a bigger obstacle to most problems than engineering/science as shown with Climate Change or even fucking potholes..

>>10953761
>Tennis racket theorem only applies to objects with three distinct principal moments of inertia
Which happens to be all objects in reality.

>>10953780
No, you're a fucking idiot for not taking into account the expense of getting the mass to make the foodstuff into orbit. A space colony exporting food is an open system, eventually you run out of mass with which to make food and have to import more.

>>10953835
If the colony is exporting food they would have the income to purchase the required inputs. I can only agree that foodstuffs are not the most valuable product an orbital colony export.

You seem to be an angry little man who doesn't want to believe. Any meaningful colony must be self sufficient. That includes food production.

>>10953964
>>exporting food
fucking where
>> would have the income to purchase the required inputs
prove it. Transporting stuff in space isn't free. The cost of propellant can be quite substantial.
>>who doesn't want to believe
I don't believe open system space colonies are very practical.

>>10953761
What? Farming in the colony would be way cheaper then piping food to it every week

>>10954179
How do you supply a space colony with food if it isn't self sufficient

>>10954224
He is blinded by mindless rage and only wants to argue.

>>10948916
>What would be the cost of making a said space habitats with today's technology?

more money than exists.

>>10954910
It can't be that expensive compared to some buildings we've built

>>10950297
>The stationkeeping requirements for that are onerous.

Nope. Station-keeping requirements in low orbit are still on the order of tens m/s per year. This is insignificant. And you can do this with efficient electric propulsion, as there is no rush at all.

https://en.wikipedia.org/wiki/Delta-v_budget#Stationkeeping

>>10952370
>Oh for fuck sake. You guys really don't understand how much the ISS is shielded from cosmic radiation via the magnetosphere

Not very. See this picture. ISS receives almost half of the GCR dose of deep space, and most of this decrease is due to Earth shielding almost half of the sky, not due to magnetic field. It also passes through South Atlantic anomaly.

This is one reason why astronaut stays on the ISS are limited to one year or so.

>>10955493
>not understanding what you are
>post it anyway
Oh, for fuck sake. I'm sick to shit with these threads.

>>10955481
L4/L5 are stable and aren't full of satellites and debris.

>>10952370
>To have something sufficiently thick enough to block long exposure detrimental radiation is to have something that isn't going to work as a window.

Instead of vague statements such as this, here are actual numbers. 1 ton per square meter of high density polyethylene will halve the cosmic ray dose. So this is roughly the half-value layer.

Now, you need several of these halvings to reduce LEO GCR radiation flux (around 200 mSv per year) to something safe for children and pregnant women (say 20 mSv per year). So think several tons per square meter of shielding. This applies not just to windows, but to whole habitat volume.

>>10955505
Sure. They are also much further from Earth both in terms of distance and in terms of delta-v, and with much more punishing radiation environment. Not a good choice for our first space colony.

>>10955510
You wouldn't build with terrestrial materials. You start by moving an asteroid to the lagrange point. Then hollow it out for ore and work/living space. Tools, forges, etc are flown up from earth. You set up and the mine the moon. Lots of surface titanium on the moon. Build the cylinder or torus attached to the rock. Then once finished it departs from the rock. Then the colony moves to the other lagrange and builds more colonies. While the original rock station is building another. After the second colony. The rock is stripped and then mined for ever last valuable element.

>>10955545
A nice sci-fi vision, but this is not the first or even the second step. The first step is a colony in equatorial low Earth orbit, right at our doorstep (and a surface of Mars, but that is another discussion).

>>10955446

are you actually 12?

do you know that it costs 10000 dollar to bring a kilo of mass into orbit?

>>10955565
It costs $2000 per kg. Also, this cost is a function of launch rate mostly. Put a contract on the market to launch thousands of tons, and this cost will decrease significantly due to economies of scale. $100 per kg is a realistic scenario when using advanced reusable rocketry and launching every day.

>>10955507
What about using water

>>10955611
Water is in the graph, look closely. It is slightly worse than polyethylene for shielding.

>>10955650
Oh my bad do aluminum is the best type of shielding we can get?

>>10955717
Polyethylene is the best according to that plot. Makes sense, because the lower atomic number, the less secondary radiation there is. And polyethylene (basically H2C) is two protons lighter than water.