The Stanford Torus Space Habitat

[@isaacarthurSFIA]

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[@rayceeya8659]

Imagine riding an elevator from the ring to the axle. You gradually go from 1g to 0g. It would initially feel like you are moving up but as "gravity" decreased, you would quickly begin to feel like you are accelerating downward until you feel you are in complete freefall. One hell of a carnival ride.

[@peeperleviathan2839]

Also you would be pushed into the side of the elevator as you rise

[@rayceeya8659]

@@peeperleviathan2839 True I had considered that. I imagine that for maximum comfort the cabin would rotate to give some semblance of normalcy. Otherwise. perhaps a sloped floor of some sort. So that for a period at partial g you are sort of standing on the wall. Like in teh Gravitron carnival ride but with far less g-force.

[@Suillibhain]

Wouldn't inertia give you a partial gravity until it begins to slow?

[@toomanymarys7355]

​@@Suillibhainno. Acceleration does. Not velocity.

[@toomanymarys7355]

​@@peeperleviathan2839No.

[@flykiller]

It's refreshing to see some smaller-scale projects that could be built within a more feasible timeline after many gigastructure videos.

[@DeafaningEcho]

Agreed

[@RCAvhstape]

Agreed also, but of course by the second half of the video he's talking about tearing down moons to build billions of these things lol. Gotta love it.

[@Alex-wg1mb]

Bernal sphere or ellipsoid is also a cool project to build. Eh i wish to live long enough to visit such station myself

[@antred11]

Yes, I much prefer this over all the far fetched, pie-in-the-sky-may-as-well-be-magic stuff! 👍

[@isaacarthurSFIA]

We'll be doing the Bernal Sphere, Hammer Habs, and O'Neill cylinders next, about one every other month

[@nickv8334]

Always nice to see that you still like my 3d models and use them for your backgrounds. (2:47 and 3:43 for example). If you ever need a model like these 2 for a upcoming video but don't have something that fits, let me know. If it is for one of your video's i dont mind making one for you free of charge.

[@marcel1653]

@nickv8334 Thank you for your contribution to the channel! I really like your habitation designs!

[@likemau5552]

I like the second one, good sense of size and it is the closest to what i see when I imagine a rotary habitat ❤

[@Wordsmiths]

You are awesome. Keep up the good work!

[@partciudgam8478]

nowdays: "Dad, I want to go to Stanford" "are you insane? that'll cost a million bucks!, go to the community college!" immagine this conversation in a hundred years: "Dad, I want to go to a Stanford" "just take the rocket kid, you are old enough to fly, just call when you dock" now that's progress!

[@EstamosDe]

Elroy Jetson style

[@realNikoCousin]

Forever frustrated by this lost opportunity

[@Dima-ik3bt]

Why waste time on long-distance rocket flights when you can experience it in a fully immersive VR?

[@sevensins3584]

I wish more scifi movies were a about realistic space habitats. I think living in space is almost interesting enough that you dont need aliens or war to make it a cool movie

[@delphicdescant]

This is what I've been looking for ever since reading Rendezvous with Rama. It was the first book in the series, but the rest of the series felt the need to introduce human conflict, drama, war, etc, instead of just allowing the reader to continue to bask in the glory of the megastructure. But a lot of writers or hollywooders believe that you can't tell a good story without character drama, so here we are.

[@giovannifoulmouth7205]

I wish more scifi movies got at least the basics right, like microgravity.

[@efraim6960]

there's an anime series called planetes

[@mirandela777]

Read / watch "The Expanse", is way better than Sir Arthur books... just because are from modern time, with incomparable more content, and why more deeper. I think the Expanse series is THE best SciFi book(s) written in the last 20-30 years, and the most realist SciFi movie in the last 40 years.

[@delphicdescant]

@@mirandela777 Meh. The Expanse is good, like a solid 8/10. But the people who say it "ruined other sci-fi" are full of it. The worst thing about The Expanse is its fanbase. It literally has just as much science fantasy tech as anything else, but its fans pretend it's the ultimate "hard" scifi lol. Frankly, Clarke wrote better fiction.

[@comentedonakeyboard]

5:51 since i've just did my laundry, i used the oportunity to ask it about centrifugal force. Unfortunately it excercised its right to remain silent, instead of giving me the entire laundry list of complaints i expected.

[@isaacarthurSFIA]

:)

[@herzogsbuick]

it really hampered your understanding

[@matthewboire6843]

Hehehe funny ;)

[@innerstrengthcheck]

I love seeing videos about smaller-scale habitats alongside the same channel as Dyson Spheres and Matrioshka Brains!

[@fremenondesand3896]

I find it funny showing a picture of an O'Neill cylinder with forests and overhead telegraph poles (made from wood, why not?) when you've got all that underground where you could route conduits.

[@isaacarthurSFIA]

Well we've a lot of ground under us here and still do it, but agree, if you're literally building your ground it make sense to include that infrastructure while you're doing that.

[@fungalcoffee]

Could just be decoration, going for a vibe.

[@kahlzun]

Overhead wires do have some advantages too, especially if your habitat doesn't experience much wind

[@jackesioto]

Though I'm guessing it will be purely an aesthetic option at that point.

[@arcadiaberger9204]

I definitely like the idea of using water for shielding on space habitats. Immense reservoirs of drinking water, sewage treatment plants, fish farms, even aquariums (one layered above the other - why not?).

[@Darkfirephoenix3010]

A Torus would also make a good starting point for more expansive space settlement. They are relatively easy to set up and "cheap", great for when it is the very first space habitation in that area/star system. Set one up near/at an asteroid belt to harvest and process raw materials into construction materials to build more/bigger space habitats, ships, supplies etc. You could even have one ring for habitation/farming, another one for processing raw materials (for those that need/are easier to work with in gravity) and another to turn the processed materials into needed end products.

[@comentedonakeyboard]

And can easily be scaled up by attaching more toruses.

[@jeffreyknutson]

My thoughts are much the same!

[@DerekJones1081962]

I'm glad that you used the Stanford Torus as a jumping off point for an update on advanced habitat design.

[@videojosh20]

Today, I'm thankful for Isaac Arthur dropping a new episode!

[@krumuvecis]

Some improvements: the radiation shielding doesn't have to be spun up, it can be a stationary shell; there have to be at least two counter-rotating rotors, to preserve the angular momentum while accelerating/decelerating electrically; these lead to having a non-rotating axis, to which there will also have to be some rotating guide wires, to control axial stability; the rotors themselves and the guide wires will have to be connected to the non-rotating axis via some serious bearings, maybe magnetic; all of these parts have to at least be duplicated for redundancy, meaning at least 4 rotors, multiple sets of bearings and guide wires per rotor, and possibly multiple non-rotating axis. Knowing the maximum tolerable Coriolis effect is really crucial here, since it influences all of the above. By my rough napkin calculations, the rotor can be no smaller than 1km in radius, but it could need to be bigger.

[@jeffreyknutson]

This is gonna help me out with my project a lot! Thanks!

[@R.Instro]

To me, one of the obvious advantages of having the full-scale massive habitat is that the occupants themselves are of low enough mass not to inherently destabilize the spin as they move about the structure. As you go smaller, you'll need to start actively cancelling those shifts in the center of gravity, which adds a lot to the complexity of design, as well as the failure mode space. Honestly: for spin-based gravity, bigger is always better.

[@bar2605]

Happy Thanksgiving everyone.

[@oriontheraptor8119]

To you as well

[@matthewboire6843]

Oh right, it’s American thanks giving isn’t it? Happy thanks giving!

[@LineAlpine]

I would love to see a series of more near-term topics and concepts, perhaps even Isaac’s vision of the next several decades. Could make for a good narrative as well?

[@Chron0ClocK]

Topics like this make my head spin!

[@isaacarthurSFIA]

I'm going to have to steal that line the Next time I talking spin-grav :)

[@darthnihilus511]

😂😂

[@juimymary9951]

Happy thanksgiving! Also great that you are bringing up some smaller scale projects! :D

[@Mike-11235]

The banded torus is my favorite design for a space habitat. I'm not an engineer, but I think it would be one of the the most low-tech options, and the safest option. We probably could build one out of modern day alloys. With a standard cylinder, the whole thing would need to be evacuated if there was a major breach, or if it needed to be rebuilt due to age. With a banded torus, only one ring would need to be evacuated in the case of a breach. Also, you could set up a schedule where one new ring is added to one end while the ring on the opposite end is disassembled: this removes a lot of maintenance headaches.

[@Samuraix47]

Science Fiction author James P. Hogan has a few novels with Stanford Torus habitats. Two Faces of Tomorrow, and Voyage from Yesteryear. And there’s another novel but can’t recall the title where it’s built underground and each section of the torus is slanted slightly away from the center as it has to take real gravity into account for the interior to seem normal. Similar to the spinning bowl design but only the widest part. I once saw a YT video about Mars colony that used a similar toroid to simulate 1g in mars gravity.

[@seditt5146]

I feel our best hope for actually making a space habitat is going to be to spin up a rubble pile asteroid, capture it in a net until it forms your torus or sphere and infuse the rubble with some sort of glue or UV reactive resin that finds its way to the bottom and forms a shell binding everything together and giving a smoothish exterior. I just don't see us being able to send all this mass into orbit anytime soon so we may as well work with what we got up there. The constant change in material properties would likely provide superior shielding compared to a Mono-material like Aluminum as an incoming bullet would be deflected around in the material every time it hit a boundary between boulders.

[@KentoLeoDragon]

I still remember saving up my money and buying myself a membership in the L5 Society when I was in highschool. Good memories.

[@tonyportcullis488]

Happy Thanksgiving Everybody! Gravity health is important. 0-g isnt healthy. We need more data. Doing spin gravity experiments with the grandkids after dinner.... Thanks Isaac

[@robertadsett5273]

I prefer inertial force to pseudo or fake force. It more clearly describes the origin while not suggesting there isn’t a force that can be felt

[@OOL-UV2]

Or, the “not a force” snarkmeisters could stop their pestering and call the “real” forces what they are: fundamental forces. Sophistry sucks.

[@Nyctophora]

Thank you and happy Thanksgiving to all who celebrate!

[@patromo]

Happy Thanksgiving Arthurites

[@calebkirschbaum8158]

At 25:42, how would gravity work on that ship? Would it be changing over time? That feels like a motion sickness machine, absolutely great for prisons.

[@greggweber9967]

10:45 Does the difference in "gravity" between the feet and brain have a bad effect?

[@toomanymarys7355]

Less than 250m will definitely make people sick.

[@peeperleviathan2839]

@@toomanymarys7355you think so? People can’t even feel a change of gravity below about 0.05G which would make the minimum radius be 35-40 meters not 250 meters

[@wroughtiron7258]

The huge advantage of Stanford Hoops is that they can be built in stages and eventually expand to become O'Neil cylinders. You start with just spheres or so-called dumbbells and just keep adding more dumbbells until they become a hoop and then add more hoops along a cylindrical axis until it's an O'Neill cylinder. It's not an either or design. One design becomes the other. Also I would like to note that if you build one inside of an asteroid you don't need 98% of the mass for shielding because you can use the mass of the asteroid for shielding. Turning the abundant silica into aerogel mounded up on the outside surface of the asteroid to provide abundant radiation shielding for boreholes containing Stanford hoops inside.

[@RCSVirginia]

Though, of course, not a true Stanford Torus, the space habitat featured in the movie "Elysium" inspired one of the best lines that I ever read on KZbin, and I would give credit to the author if I could recall who it was: "Elysium II: The Sequel: Everyone dies when the new inhabitants pawn all the life-support equipment for cash." It does show that future space-habitats are going to require responsible and non-destructive inhabitants if they are to succeed and survive.

[@pseudocalm]

My take on this is that we will (eventually) learn how to build and design in overly redundant ways, to account for the 3% - 8% who self destruct into greed or despair, or would jeopardize a remote location over time. Maybe even designing honey traps of sorts into entry level jobs / chores. Traps that look like opportunities for misdemeanors, that at 1st and 2nd glance they can get away with, progressing all the way to some human to human psychological sting operations. This is just the sort of unfair and brutally manipulative tactics the FBI will occasionally use on innocents that FBI thinks could act on terrorist inclinations if given the opportunity. FBI used to be much less ashamed of spending weeks with these targets, drawing the worst out of them over time until they explicitly agree or ask for help to do the crime that the FBI was explicitly pushing them toward. These are tactics many people on earth don't agree with, because the evidence seems to suggest we are all malleable enough to self justify minor aggressions, and given enough time, incentive, and opportunity maybe major aggressions too. But if I was running a station on Titan with only 150 population, and I needed 100 of those ppl to be very competent, semi autonomous, and serve in positions with high responsibility and liability, while staying resistant to corruption or despair, I might want to design 3 or 4 layers of these types of honey traps, to find the 3% i need to send home or lock up quickly, and to find the 5-10% that I need to keep away from heavy responsibility / autonomy. Or. We will not eventually learn redundancy, and human nature cannot be filtered away with clever cultural tech/tests, and we all desire a freedom we will never have, which would mean the only solution is prison/stockades and a dependance on space police + lawmakers who tend to be pretty corrupt themselves half the time. The answer to "*where is everybody*" could be the same answer to "where are we?"" = still figuring out how to human nature our way around a single solar system in the name of science, still with no real plan other than "learn all the things so we don't go extinct, still fighting each other on a larger scale than we are helping each other.

[@UrdnotChuckles]

Ah, one of my favourite station designs. And one I use fairly often when writing. :) I rather like the idea of having a few levels of living space below the "open air" segment, and having a microgravity dock in the middle for ships, shuttles, or whatever else that doesn't need spin gravity. I also like the idea of nesting a few rings together around a common axis to give variable gravity options. Have an Earth gravity ring, a Mars gravity ring, a Lunar gravity ring, etc. Could be useful!

[@extropiantranshuman]

sorely needed video. I hope we get to see a von braun design hashed out in a video one day.

[@samedwards6683]

Thanks so much for creating and sharing this informative video. Great job. Keep it up. I have already booked my room!

[@bclapp2483]

Colony's in space was the book that sparked my interest in space decades ago. Thank you for covering it 🙂

[@zico739]

One of the classics!

[@dogprowilhelm7630]

The real interesting about a Standford Torus is on a large scale it could be used as a gravity tug for asteroids and deflect away from Earth, or to be mined. Don't forget rotating instability with symmetrical spokes and think in 3's instead of 4, Issac. Awesome topic.❤

[@lightlegion_]

You’re incredible at what you do!

[@TimStCroix]

I've settled on a coaxial 2-torusl design. The outer torus is, of course, shielding with the inner torus the living area. They spin in opposite directions, solar panels on the outer torus producing electricity used for spin up and spin down as well as for use in the inner torus. The inner torus is, basically, a magnetic levitating train in one complete loop. The outer torus has a slot on it's inner edge for ingress/egress of personnel and materials as well as reflected sunlight from mirrors mounted on a central spindle. Close to the sun, spindle mounted thermal radiators will have a much larger area than the mirrors while in the outer solar system the their ratios will be reversed. Piping of radiator fluid, or other heat transfer schemes, will have to be addressed. The inner slot will have walls of shielding material on both sides to block the path of radiation. They would be high enough so that looking up through the walled slot will not see any space but the opposite side of the torus. That's all I've got so far.

[@ViaAvione]

Really neat! Thank you for sharing.

[@tolep]

13:32 - When unit conversion went wrong.

[@sethapex9670]

A bit over a year ago I had a friend pitch to me the idea of a spherical rotating space habitat consisting of two counter rotating hemispheres, that could be adjusted so that it would have 1g normal gravity felt at every point inside the sphere, though it would need an outer shell to keep air from leaking out the seam between the two shells even though most space Habs do have such a shell or would require one at some point in construction.

[@BlackEpyon]

Screw Mars, give me Lagrangian space colonies!

[@andrecoleman9549]

I agree. I think it would easier to do early on in our adventure. But... They would be mighty close to earth and we just can't seem to keep our hands off of each other's property! Its...sad...😢

[@giovannifoulmouth7205]

lol Mars will be settled looooong before space colonies of any kind

[@BlackEpyon]

@@giovannifoulmouth7205 Very likely. Even though orbital colonies are far more efficient, given that you don't need to fight a gravity well to exit the colony, they require a significantly higher investment in infrastructure and resources.

[@NaStEric]

Don't forget gundams, space colonies need gundams

[@lesgamester7356]

Thanks for this presentation.

[@DeltaVTX]

Coffee and space donuts!

[@JFrazer4303]

In "Spaceflight" journal of the B.I.S., Shepard wrote about using reinforced concrete as the structure of the torus. It makes a more robust habitat shell than using metals to "hold up the weight" of shielding against the "gravity". It uses less metal than the typical metal shell structure, and it uses metal in the form of cables: metals under tension bear much more structural strength than as plates and girders. The artificial aggregate rock and the metal cable are easier to inspect and repair. The largest structure we've made of metal is something like a supertanker. We build dams and bridges massing much more, out of artificial aggregate rock. Rock structures last thousands of years, metal structures: barely 30 years with constant repairs. Artificial rock and metals drawn into wire are bronze age technology, easily made in a "boot-strap" space factory.

[@einherjar8585]

Gateway has a number of designs for ring habitats, building tauroids in space, construction drones, etc... I have been watching their development for several years now... they have a number of vids here on YT.

[@extropiantranshuman]

3:00 who isn't obsessed with the o'neill cylinder? It was my first favorite video on this channel!

[@jameschastain1229]

I wonder if he has done a video on the ideas on expanding asteroids for habitat/station John Ringo used in Live Free or Die. The aspects of the mining methods, expanding the asteroid, and building inside of it when it’s completed.

[@DEMONOFLOVEANDDEATH]

Bless Isaac

[@AllYourMemeAreBelongToUs]

7:19 “Folks have mostly stopped repeating the ‘centrifugal force doesn’t exist’ truism.” Now if only we can get them to stop repeating the “purple doesn’t exist.” truism. Wavelength and color aren’t the same thing all colors only exist is our minds not just purple. What makes purple different is that it is a non-spectral color. But that doesn’t make it any less real than all the others.

[@isaacarthurSFIA]

I think that's magenta, isn't it?

[@AllYourMemeAreBelongToUs]

@@isaacarthurSFIA No, the truism is often quoted as purple OR magenta, either way both statements are false. Non-spectral colors are just as real as spectral colors. _Color_ isn’t a property of light _wavelength_ is, and they aren’t the same. Otherwise metamers wouldn’t exist. And two organisms can look at the _same wavelength_ of light and see _different colors_ . Color cannot be sensed, it can only be perceived. Wavelength can be sensed.

[@theeyeofomnipotent]

​​@@AllYourMemeAreBelongToUs hey because of the seperation, you can reroute colour perception, for example the perception of wavelenght of blue to red and vise versa, and I don't think we can objectively tell a person have those, even then we don't know if "blue" is the same for other people, as colour itself is more related to consciousness than of reality,

[@AllYourMemeAreBelongToUs]

@@theeyeofomnipotent This is mostly my point. It doesn’t make sense to any color exists more or less than any other color. Because they are all perceived not sensed.

[@theeyeofomnipotent]

@@AllYourMemeAreBelongToUs can such qualia be enforced to other observers *so they can know our colour is correct? * hahaha and make the blind know of our reality, that said, I wonder how tetrachromacy or higher work, they seem to be able to pick out more colours, what are they actually seeing? On that note, I'm curious upon feelings I haven't felt before, I'm curious what other feelings exist beside the basic ones, I'd like to see new Colours I haven't and couldn't perceive before, and like you imply, it has to be done by modification to the internal system of experience itself

[@aceundead4750]

I think a large chunk of the centrifugal and centripetal forces not being real was largely due to people in graduating classes of 2010-2013 were being taught in school one or both werent real. Woulda been class of '12 if i hadnt dropped out, and until i dropped out and started watching more science shows that was all i heard.

[@David-p9y9c]

That scene looks like they used a hybrid bike tire for the FX

[@2jlee]

Have you heard of the fractal space station design? I saw a presentation booth at ISDC one year where a guy was showing a scale model, along with a video demonstrating the interior and expansion mechanism. "Seed" stations could be built on Earth or another station then sold. The station could then be built up in stages / layers on the inside then the station expanded through a mechanism of some sort such that that new layer/stage becomes a segment on the outside, with expanded interior space. It would be fascinating to get a video with more in-depth discussion of space station designs that can grow over time, without all of the work needing to be done before habitation and in vacuum.

[@2jlee]

Of course I found Isaac's video on Self-Growing Space Stations right after my previous comment. kzbin.info/www/bejne/b5K1o55uet6Heq8si=yQjelJtPzsVTl3dg I don't think it covers exactly the expandable space habitat I was talking about, but it at least covers the general idea.

[@Yoel_Mizrachi]

I expect the 'centrifugal force doesn't exist' folks number will start to decline when we have large rotating space habitats with elevated platforms and balconies that we could push them of so they can figure how real is centrifugal force is..

[@YH-du3jc]

Space defenestration

[@animistchannel]

Happy Thanksgiving! Let us be grateful to live in a time when such scales of development are conceivable. As to habitats, you got a particular aspect so very right here. Yes, you can build (clusters of) cylinders, but they don't need windows to see streaking stars zipping by. You encase them in a shell and use the 0-g spaces for storage of fuel, minerals, propulsion modules, and industrial facilities. Life forms need gravity. Cargo and machinery do not. What all of it needs is some kind of armor against the rigors of space, physical and energetics. Lightweight foam-regolith-epoxy-polymer scales or plates on the outside of the exterior shell can absorb plenty of tiny hits, and buffer many bigger ones, as well as making the cosmic rays/'UV+/photons not an issue at all. Thanks for revisiting these basic concepts! Yes, designs are plenty and have been around for decades, but we are still waiting on the heavy-lift vehicles to make the first ones that can go out and make the next ones, etc. Perhaps the start dates for these projects are upon us soon after all... Thank you for all you do!

[@MrTubeuser12]

28:40 "I don't think we'll build one this century" so 2101 A Space Odyssey then ? better late than never I guess lol

[@hughdanaher2758]

Regolith launched from the moon can be formed into the shielding and soil. Carousel habitats on the moon could be manufacturing panels for shielding the space stations.

[@js70371]

Once we begin space mining it’s not outlandish to assume we could build such a structure in the next 100-200 years

[@4124V4TA-SNPCA-x]

You mean 100-200 yrs post commercially successful space mining?

[@js70371]

@@4124V4TA-SNPCA-xyes 👍

[@js70371]

@@4124V4TA-SNPCA-xyes, from the time we start producing usable materials in space

[@djdrack4681]

'1 acre' implies only 1 horizontal growing space. Modern industrial greenhouse aggriculture, or permaculture/aquaculture has many layers of growing or 'food' space. Any rotating habitat could have 1/acre per family (of 4), but like a Rowhouse may have 2-4 stories, you'd have 10-15 stories. 8-12 stories of greenhouse/aquaponic/fungiculture. 1 story of living/working space, connection to habitat Xportation (IE monorail road). 1-2 stories of habitat processing, atmospheric recycling, water treatment, etc. Maybe 1-2 stories of fauna grazing (IE cows, chickens etc) - Methane from cows would get separated as part of atmos scrubbing, compressed and reacted/converted to propane for fuel/heat (to offset solar burden). - Manure would go through processors (w/ proper bacteria) to help convert it into fertilized compost after mixing with urine waste (that gets nitrated) for Urea Nitrate + Ammonium Nitrate. - Chaff (IE corn husks etc) could be carbonized via burning, recycling potassium/sodium etc in the ash, nitrating it for fertilizier, and reusing the carbon leftover. A large % of any habitat would be maximizing recycling. We don't do it on Earth as its not 'economic' but when getting mass into space is extremely expensive...you reuse as much as you can once its there...Indefinitely.

[@smoore6461]

When you said "single Family" the first thing that came to mind was Tessier-Ashpool. :) Great episode as always Sir, hope you and your family have a fantastic Thanksgiving!

[@ronaldreeves421]

At 23 35 you show how it equates to suspension bridge. So why not use cables as spokes in wheel and coridoor spokes can adjust lengths as needed. The cable spokes can have automated tensioners or magnets on them. It seems more reliable especially for thermal stress or in any collision. It might save weight. I always wondered why magnetic docking wasnt used it self aligning. The center hub of station can be magnetic, maybe even AC and rotation could speed up or slow down to store energy, for example if docking ship can transfer momentum to station or when leaves can get a boost from station. Having an array of spinng ionized particles trapped in magnetic feild could help shield against radiation, these could be small as molecules or larger, their spin multiplies effectiveness as shield against radiation or micrometeors.

[@cesarvidelac]

Love your work, subscribed!

[@corwinzelazney5312]

There's several designs for one person sleeping pods on the end of a retractable tether, with 2 to 4 pods attached. These designs are less complicated than the ISS toilet - by a lot. And attaching it somewhere on the station wouldn't be too difficult. This simple device would alleviate a lot of the destructive effects of long term weightlessness on the human body. Astronauts carry the consequences of long term weightlessness for the rest of their lives, and it's preventable with something like this. We can build most of the designs with current technology. Hell, the tether designs have been possible since the 70's with then current technology too. For anyone saying the cost is too great, let's calculate the cost of all the equipment used to prevent the effects of weightlessness and the long term healthcare needed for astronauts for the rest of their lives. Besides, any manned mission to Mars or beyond will need artificial gravity. We're going to have to start somewhere. Why not start with something small like this.

[@Pystro]

On the topic of using natural light: the direction from which the sunlight enters your habitat will inevitably also allow radiation and micro-meteorites in. Unless you routed the light through 4.5 meters of water, or 4 meters of acrylic. I think using water will be the way to go here. Obviously, only 4% of the red sunlight and 98% of the blue sunlight will make it through the water. The red side of the spectrum will almost definitely need to be supplemented by artificial light. But the absorbed portion of the light is not actually lost because it's also providing free heating to counteract the water's radiative heat losses to space. Then again, everything but the "sky light" can be thermally shielded effectively; so those losses are only unavoidable _because of_ the giant window to space. A second way around the radiation risk is to have a parabolic mirror that focuses the light onto a small opening, where the amount of radiation coming through that opening and the risk of a micro-meteorite hitting exactly that spot of the hull are negligible. And on the interior side of the opening you let the light spread out as much as you can and then use another mirror (think disco ball, except matte instead of reflective) to spread out the light. However, at some point you'd run into the problem that the amount of light that you want to send through that small area heats up the glass or acrylic or whatever you're using. And then you'd also have the same problem again at the "disco ball", except that it's slightly less severe because the light can spread out a bit before hitting it. If you _really_ want to go with the un-shielded opening strategy, then you could even leave the sun hole open. I.e. you simply accept the leakage of a bit of atmosphere to the vacuum. A third option is that if your atmosphere has a thickness of 4.5 tonnes per square meter, then it can function as the shielding. For comparison: earths atmosphere has a mass of 10 tonnes per square meter. So 4.5 tonnes are _theoretically_ achievable at 1 bar of pressure, if you have a 30 kilometer radius O'Neill cylinder or thereabouts and let the light enter near the axis.

[@JFrazer4303]

Better, is the simple solution used in the Stanford Torus design to block cosmic rays and allow Sunlight. Mirrors bounce Sunlight in through a zig-zag path.

[@themercer4972]

Watching this has given me an interesting idea for a sifi story. Remember the old cartoon Rocket Robin-hood? There seemed to be a lot of asteroids, all with air and gravity, so the characters could fly from one to another for various adventures. Each asteroid was more or less a small county, in medieval terms, with a village, a castle, farmland and forest. The basic setting idea works very will this space habitats. The feudal system in the far future, can have a minor lord owning a small Stanford torus, while a king would dwell in an Oniell cylinder.

[@jacksnavely559]

We would need too have special entrances or we may step from not moving too moving full speed in a step ?

[@Warchin007]

What kind of o'neill cylinder would be created in L-4 or L-5 at first ? (Primary need) What would be It's main purpose? First o'neill cylinder ? (Reason for building first one) Happy Thanksgiving 🦃 🖖

[@jjkthebest]

When I'm imagining sci fi worlds, I go with hammer habitats that are built in a way to allow adding modules until you end up with a torus. After that, there's additional ways we can combine things, albeit increasingly impractical. Maybe for the next step it would be better to just create it as is. But anyway... perhaps we can design the torus in a way that we can keep adding toruses together to create a cylinder. Maybe at some point we could attach walls to the sides of the cylinder and add in enough air to let us remove the roofs and create a proper o'neil cylinder.

[@cannonfodder4376]

Happy Thanksgiving and another wonderful video, Isaac!

[@isaacarthurSFIA]

Thanks! You too!

[@RamingtonStilll-x4b]

The battleships of the Cylons in the original incarnation of Battlestar Galactica, seemed rather practical in their design. Though means of space drive was questionable. Don't recall where they kept engines. The wonders of sci-fi.

[@amlanmohanty1233]

Is there any chance, we'll get a live stream Q&A anytime soon? I have so many questions!

[@wolfvale7863]

The other day, my 5 year old read the word "Licorice" as "Lico o rice," not the correct pronunciation, "lico o rish." Language also has problems with naming.

[@demonicsquid7217]

Lick O'Ricky

[@multilevelintelligence]

I would like us to think about how it will progess from the smallest possible space station up to the mega sctructures. i think this growing phase will dictate a lot of how this will look like.

[@KulpimsTdna]

Is it based on Noordung design from 1930's? Herman Potochnik Noordung described the habitat wheel in his book The Problem of Space Travel: The Rocket Motor, published in 1929.

[@matthewboire6843]

Space habitats are always interesting to think about.

[@Pystro]

12:56 "[...] A space habitat with lawns and gardens and lakes always seems like a crazy idea _until_ you remember the shielding issue." Isn't the amount of shielding proportional to the surface area? I.e. if you waste space on lawns, then you need to shield those lawns. So the shielding is very much why lawns _are_ as crazy as they seem. In reality, you might want habitation and all other areas that humans frequent on a consecutive series of levels, and suspend underneath those structures the shielding (soil) with greenery and lakes on top of the shielding. And some installations that humans won't have to frequent (service corridors for wires and pipes) can go underneath (or partially underneath) the shielding. But on the other hand, all of the surface area of the shielding is just too convenient a location for the greenery, so you wouldn't cover that surface up with homes and offices. As a result the greenery will most likely not be connected to your home. Think parks, sports fields, nature reserves and probably personal garden parcels, not back yards. This is equivalent to how our current technology _would_ allow us to have grass verges in the hallways of our multi-story buildings, but you have to pay out of your nose for the water proofing to make that possible without wrecking the structure of the building. So the greenery in them actually comes in the form of planter boxes in lobbies, and pots on your window sill. And lawns and rows of crops are limited to the surfaces where we don't have to think about water-proofing: on the ground.

[@jp12x]

This morning, I ate a tomato I grew without soil. Why grow crops in soil? The outside edge needs mass like water and has easy access to light. Aquaponics and hydroponics are worth covering :) Thank you!

[@oneeyejack2]

I think what we must consider for this design is - structural stability (the forces and tensions at play when rotating) - scalability (because we probably won't build a giant habitat right away) - dynamic stability (the ability to balance the rotation continuously if we expand the habitat or add various masses inside, to avoid precession) - security : what happen if a part of the habitat is blown… Does everybody die ? There are tons of scenarios to be considered - thermal flow (because the inside must be warmed) : the surface area in contact with space - and also what do we keep in zero G ? we would probably use some sun light (for solar panels or plants) so a spinning thing would lose half the exposure... we would probably be better having a constantly dark side (for thermal dissipation and usage of the cold.. we need "cooling" for computers and stuff) and a constantly hot side (with solar panels and plants), instead of having everything alternating "cold and hot" when the thing rotates. That would make a great video game : a "city builder" where you can attach "beams" and "habitat block" and rotating blocks etc with population management with a bit of mechanical/thermal simulation...

[@ThomasDillon-z6u]

May the centrifical force be with you.

[@lsa_03_deveshpatwari40]

Happy Arthursday

[@jockeb2651]

Aaaand happy Arthursday!

[@FoxtrotYouniform]

maybe its finally time for me to make a video about my Atlantis Station

[@braddl9442]

Each one seems like it would be made for different purpose. Spheres types seem like they could be useful for shipping and trade and research manufacturing as the differing gravity zones could have advantages for certain projects. Hammerheads for actual ships traveling around long term. The Stanford Torus for General purpose mixed use this would be the type companies might use for their purposes in space or scale down to a small community of family habitat. And the Cylinders for long term living colonies, I can see schools and food production being the main purpose of these types.

[@Vaasref]

I like my torii with an engineering deck, a pleasure deck a bio deck and a lot of scuzzers.

[@NoirMorter]

At 20 mins with the station you're talking about, what infrastructure would have to be in place to develop those stations. I am assuming that space based resource extraction and refinement would be a must as well as some manufacturing. But what about meat and other food? I'm not a fan of some of the other plans and vegan diets I've heard.

[@Kaboom-0623]

the main reason for nausea in spin gravity habitats is the change of gravity over the height of the person or space ... the smaller ones will have a large change between floor and ceiling ... while the larger ones will have less if any .... a change of more than 3% from normal between head and feet will cause nausea .... most common for average people is 1.5% change in gravity for little to no effects from it ... for example a ring doing spin gravity test on the ISS would need a counter rotating weight or second ring to offset the spin it will impart to the station ... and the gravity will be highest on the floor so great place for rowing and lay down peddle exercisers and even beds ... stand up and get motion sickness .... the reason being at the spin one can safely do on that small a scale is still 1 or 2 rev per minute BUT the change it force will be much different between the floor and the ceiling ... 30% or more change (a few inches at any steady force)

[@tim2024-df5fu]

Has anyone done any weather modeling for an O'Neil Cylinder? That's a lot of air being rotated at different speeds. It's bound to do something.

[@Jorjgasm]

I think discussing such large shielding requirements (98% of mass) is quite daunting. I think the only reasonable solution in the short to medium term before you have huge amounts of infrastructure in space is to have active protection measures against solar storms through magnetic fields, or lasers that destroy micrometeorites that threaten your hab.

[@swedichboy1000]

I´ve always wondered, if you put a rock (lets say a couple of tons) on an axis connected to a generator in space and push said rock, would that rock generate infinite amounts of mechanical energy as there would be no drag to slow it down?

[@HarryOttele]

Here is a way to build a space station out of 36 StarShip like Crafts. The crafts will be square 40' x 41' x 32' x 41'. From the 40' the 41' side taper inward 5 degrees to the 32' side. This will be a total of 10 degrees. to make a circle it would take 36. Crafts will connect side by side but only at the living space. Ar 3.5rpm will give 1g and 2.5rpm id Mars

[@tiagotiagot]

For the long cylinder variants, O'Neill cylinders and such, do the structural design take into account the risk of a change in the distribution of mass (air pressure, fluid flow, crowds, landslides etc) resulting in a feedback loop of the cylinder starting to go slightly banana-shaped and the center and tips ending up at the bottom of apparent hills attracting even more mass to those 3 points making the situation getting increasingly worse as the centrifugal forces push the 3 points further from the axis of rotation and deeper into the apparent gravity well causing even further mass redistribution to those spots? Or are banana-catastrophes inevitable with that type of design? Is there a size range where that type of design is both usable and safe?

[@tonysannella3704]

Why do we always seem to assume 1 g as the gravity goal? Wouldn't.5 g or some larger fraction serve the purpose of keeping inhabitants healthy and stations smaller or rotation slower?

[@roccov1972]

Isaac, what would the Earth's human population have to be in order to warrant living off-world in one of these space habitats? Thanks for the cool video!

[@donperegrine922]

I don't think that we would be putting people into space habitats to solve overcrowding. We would have to be in the trillions for that to be a concern, anyway. I think the warranting will be done by economic incentives...."How much money can be made by doing science and space tourism?"

[@toomanymarys7355]

Well over 10 trillion.

[@toomanymarys7355]

​@@donperegrine922This will never be in demand enough to support space settlement.

[@donperegrine922]

@@toomanymarys7355 people wouldn't pay good money to live in a house with a garden, and the planet earth rising into their sky? Can you explain your assertion?

[@roccov1972]

@@toomanymarys7355 An Earth population of over 10 trillion? That's around 1,250 times our current population. I don't think we could fit that many people on Earth. I would assume something more like 10 or 12 billion. But that number has been argued to be larger, based on resource consumption and environmental impact.

[@lgjm5562]

I once ate at a restaurant that rotated on top of a tower . While it didn't bother me, I finally thought it was over hyped, I could understand why some would get motion sickness.

[@peeperleviathan2839]

How fast did it rotate

[@swamphawk6227]

Happy Arthanksgiving

[@dimagroza829]

Imagine being one of the engineers on the station as they spin it up for the first time and feeling the slow effect of gravity as it spins up.

[@paperburn]

40 acres and a mule was said for a reason. That was the required area required to support a family back in the days of old. I suspect that would be a very good rule. Tech of course would make that smaller but if your a dirt farmer...

[@Alex.Holland]

Max tech has this down to less than half an acre per person. maybe .25 acre. Global average for farming is jsut over an acre of arable farmland being farmed per capita i think.

[@FlintIronstag23]

The original Stanford Torus plan had 10,000 people being fed on 151 acres of land, or 66 people per acre. They were going to try to maximize output by having multiple tiers and being able to adjust sunlight, temperature, humidity and CO2 levels in the agricultural areas.

[@toomanymarys7355]

It was as much as a single worker could plow and seed during planting time working reasonable working days. It wasn't how much people needed for producing food to eat. Small landholds are generally on the order of 5 acres per family in places like India. In the tropical zone with growing seasons that permit multiple harvests per year, it can be more like 2.5 acrea.

[@paperburn]

@@toomanymarys7355 You read to much into my statement.

[@zlandicar4482]

what keeps the station from doing the spinning nut wobble then flip thing?

[@peeperleviathan2839]

The axis of rotation the Stanford Torus rotates on is stable. It rotates on the long axis (I think but if doesn’t the short axis is also stable)

[@JFrazer4303]

11:34 No, you may not add more living space by making the habitat a long tube. Yes, you can link 2 counter-rotating habs together and actively counter the inherent instability, but a good engineer doesn't design in defiance of the laws of physics and then apply complexity to counter the design flaws.