Life in an O'Neill Island 3 cylinder

[Swindle1984]

The threads about Gundam vs Battletech got me thinking. Different comments in the threads (such as the Dopp fighter being interesting, because a fighter in the center of an O'Neill cylinder wouldn't have to deal with gravity, just wind, and could basically stay airborne forever) and in the background fluff for Gundam technology (the Dopp being the only atmospheric fighter Zeon developed, and it was unaerodynamic and underpowered, giving the Feddies air dominance on Earth; the Magella tank having a turret that could detach and fly for a short period of time; Zeon soldiers panicking and mistaking lightning for a Feddie superweapon, etc.) got me to wondering: just what, exactly, would life inside in an O'Neill Island 3 cylinder be like?

I don't want the large images to mess up the thread, so here are urls for concept art of O'Neill cylinders:

http://www.islandone.org/Settlements/AC75-1086.gif

http://www.dyarstraights.com/msgundam/HABITAT1.JPG

[url=http://upload.wikimedia.org/wikipedia/c ... olony1.jpg]http://upload.wikimedia.org/wikipedia/c ... olony1.jpg[/img]

Assuming a length of 24km, just how much space would a citizen living in a cylinder have to live and move about?

What would the weather be like? Would it be like being indoors all the time, or would there be a constant breeze from the cylinder's rotation? If there's a breeze, how strong would it be? I remember a line in one of the Gundam UC series where someone (possibly from Zeon) commented on being able to tell he was on Earth just because the air was different. Was he referring to the smell, its behavior, or what, specifically? Wouldn't a better indicator be your sense of balance, since you wouldn't be able to detect the rotation on a planet like you could in a cylinder?

In Gundam, it's repeatedly stated that Zeon's troops are used to lighter gravity; would this necessarily be true, or would there be no reason not to rotate the cylinders fast enough to simulate normal gravity?

What would living quarters in a cylinder be like, as far as size and design? What about transportation systems within the cylinder?

How big a hole would be required to pose a serious threat to a cylinder of that size, and how difficult would it be to restore atmosphere after a breach?

[Stark]

The spacenoid could have been referring to air quality; there's little reason to put industry inside the habitable cylinder, and I believe it's at a rear section. Farming is done in the outer ring where lower gravity helps, so I guess the interior of a colony would just smell like trees and other things, rather than smog or whatever.

[Junghalli]

Assuming a length of 24km, just how much space would a citizen living in a cylinder have to live and move about?

The surface area of a cylinder is the circumference times the height. We know the height (or length), 24 km. O'Neill's original plans called for a height of 20 miles (32 km) and a diameter of 4 miles (6.4 km) (link). The circumference of a circle with a diameter of 6.4 km is 20 km. For a 24 km long cylinder this is an area of 482 km^2. For the 32 km cylinder it would be 460 km^2. The inner surface of the colony would be the equivalent of a 24 X 20 or 32 X 20 km rectangular plot of land. From the illustrations, perhaps half that appears to be habitable land area and half appears to be windows. I'm not sure about the ends, assuming an actual cylinder I doubt they'd be habitable (IIRC they should be sheer cliffs under the centrifugal gravity) but the illustrations seem to suggest a tapered end which I imagine makes more sense.

Was he referring to the smell, its behavior, or what, specifically? Wouldn't a better indicator be your sense of balance, since you wouldn't be able to detect the rotation on a planet like you could in a cylinder?

Just as a possibility, maybe they'd been using an exotic air mix, like say a low-pressure high-oxygen atmosphere so you wouldn't need to import large quantities of basically inert nitrogen?

In Gundam, it's repeatedly stated that Zeon's troops are used to lighter gravity; would this necessarily be true, or would there be no reason not to rotate the cylinders fast enough to simulate normal gravity?

The higher the gravity the faster the structure needs to rotate to provide it assuming it's the same size. Faster rotation increases the Coriolis effect which can induce nausea. Atomic Rocket suggest 1 rotation per minute is "safe", 3 RPM most people can acclimatize, and nobody can acclimatize to 10 RPM. Wikipedia suggests the baseline O'Neill will provide 1 G, rotating 40 times an hour (less than 1 RPM). I suspect they might have used lower gravity either because it was cheaper to build them that way (the cylinder doesn't need to be as wide) or they just prefered lower gravity for some reason.

How big a hole would be required to pose a serious threat to a cylinder of that size, and how difficult would it be to restore atmosphere after a breach?

Well the 32 km version of an O'Neill cylinder would have an internal volume of ~1 X 10^12 m^3. Assuming sea level air density throughout this would come out to an internal air mass of ~1.3 billion tons. Now you just have to calculate the flow rate through the hole...

[Swindle1984]

According to wikipedia's article on Island 3 cylinders:

The habitat was planned to have oxygen at partial pressures roughly like the Earth's air, 20% of the Earth's sea-level air pressure. Nitrogen would also be included to add a further 30% of the Earth's pressure. This half-pressure atmosphere would save gas and reduce the needed strength and thickness of the habitat walls.[13][14]

At this scale, the air within the cylinder and the shell of the cylinder provide adequate shielding against cosmic rays.[15]

[Jadeite]

This site I've found to be a useful resource while designing an Island 3 for a GURPS campaign that I'm currently running. It also concerns itself primarily with habitats in the UC Gundam timeline, which could be helpful for you.

[Ritterin Sophia]

I thought Side 3 didn't use Island 3 Colonies, but an older typed referred to as 'closed-type'?

[Zinegata]

I thought Side 3 didn't use Island 3 Colonies, but an older typed referred to as 'closed-type'?

Correct. It's essentially an Island 3 with no windows and double the population capacity. Look up, and you see a whole other city.

[Uraniun235]

How would an O'Neill cylinder fare against a big solar flare?

[Zixinus]

How long would it take to build an O'Neill cylinder, assuming that the materials can be supplied as fast or even faster than the construction rate?

[Swindle1984]

So this is something we could build today, if we actually gave a shit about space colonization.



Some more questions for those with a better physics background than me:

Wouldn't a falling object in a cylinder appear to be deflected slightly? How would this affect, say, bullets being fired inside the cylinder?

I'm given to understand that the cylinders would be paired and connected somehow so that their rotation could be used to keep them aimed at the sun (providing the most protection against solar flares and allowing controlled sunlight). Would there be a transportation system built in to connect the two cylinders, or would a spacecraft and docking ring be necessary to travel from one to the other?

How would people travel inside the cylinder? Electric cars? A small train system (like the one in Babylon 5)? Would small aircraft be practical?

I've heard references to food crops being grown in the rings, but they don't look sufficient for farming, especially since I've never seen art/diagrams of an Island 3 cylinder with windows on the rings; instead, they appear to have radio/satellite dishes evenly spaced. Some sort of old-school solar-thermal power generation system? How would modern photovoltaic power change the design, and where would crops be grown if not in the cylinder itself?

[Swindle1984]

Nope, nothing wrong with solar-thermal; we still use it today, after all.

I know the mirrors can be opened more widely to allow night time (and an unobstructed view of space) in the cylinder; can they be closed around the cylinder to act as emergency shielding against radiation/impacts?

I think this is all I need. I'm writing a short-story set in the near-future where we begin developing proposed space exploration/colonization plans after a rogue comet nearly wipes out life on earth, and I need to know just enough about the setting to give readers a feel for actually being there. If I have more questions, obviously I know where to go.

[cosmicalstorm]

Here is some relevant artwork. Serious eyecandy

[Stofsk]

Would an asteroid habitat be significantly different from an O'Neill Island? I don't want to hijack but while we're on the topic of space habitats I thought it might be interesting to look at all the options and how different they are from each other (if they are any different at all).

[Uraniun235]

How would an O'Neill cylinder fare against a big solar flare?

There's two things to mitigate it: one is producing an artificial magnetic field, to mimic the Earth's protection. The other (which IIRC O'Neill went with in his book, but I'm out of the house right now so I can't check. Gundam has them though, as seen in the first episode) is to have storm shelters inside the habitat, which are protected by their material thickness.

Oh cool, I hadn't thought of the magnetic field. How much power would that take?

[Stark]

You know how weak Earth's magnetic field is, right?

[cosmicalstorm]

Oh cool! Do you know the original source for them?

btw, something to note is almost all the artwork does a bird's eye view of the habitat. If you were actually one of the little people standing on those roads, a lot of things would look the same as on Earth - the edge of the habitat would probably be obscured by trees, hills, and buildings within a few miles.

While it is true if you looked up (not straight up - that's a window - but up/left or up/right), you'd see the other side of the hab, weather permitting, remember that's a couple miles away too. So it would look washed out and you couldn't pick out much detail, at least not with the naked eye. The artwork does a pretty good job depicting this, though I might nitpick the level of detail visible.

Some french guy made that stuff, I've been trying to contact him by email a few times but he never seems to reply. Can't find his name right now, but it can be tracked via youtube IIRC.

[Uraniun235]

I did a bit of searching, seeing as I'm clearly not familiar enough to think of that off the bat; it looks like the game changes a bit when you're talking about smaller-scale applications:

Essentially you are imitating the Earth, but on a small scale; and because it is a small scale you must use a very intense seal. It's the product of the dimensions of the field times the strength of the field that gives you a measure of the deflection; and so you need something like 200,000 gauss—that's about 400,000 times more intense than the magnetic field of our Earth—and it's clear you would have to use a superconducting magnet—i.e., a magnet in which the current-carrying wires were super conductors.

Now, they're talking about a spacecraft to Mars, which is at a different scale than a 10km-long space colony. But it's still going to need a considerably stronger magnetic field than Earth's. I'm not saying it's insurmountable, but it doesn't appear to be trivial either, so the question of "how much power" is still valid.

[Swindle1984]

I think in Niven's Known Space books, several of the Belter asteroids near Earth and Wunderland weren't merely hollowed out, but rendered molten with lasers and blown up like balloons, expanding the size of the asteroid, leaving a hollow core, and a nearly uniform outer wall once it had cooled. I'm curious how feasible that would be.

Now, let's say the world has only recently begun building Island 3 cylinders and there's only a dozen or so pairs and a solitary cylinder that was built at a smaller scale as a proof-of-concept to work out bugs in the technology and construction techniques (and as a political showboat to convince people to go along with the larger project.). Where would be the best places to put them, assuming that most space travel is still using chemical propellants and MLV's, but newer, experimental spacecraft with nuclear propulsion (both the kind using small nuclear detonations for propulsion and the kind that uses a nuclear reactor to heat and expel non-combusting propellant) are just now entering service. For reference, there is a small base on the moon designed as a waypoint for construction teams, materials, etc. as well as mining of the lunar surface. Which lagrangian points would be best for establishing these new habitats?

[JointStrikeFighter]

Here is some relevant artwork. Serious eyecandy

That is a Rama cylinder; not quite the same thing

[Commander 598]

According to wiki, it's basically a [presumably much more advanced] 50km long, 16-20km diameter closed cylinder that really makes use of it's ability to function as a moving ship.

[Crossroads Inc.]

For someone that never read "RAMA" but thinks that video was wicked awesom, how does the day night cycle work? I didn't see any open slats for ligth to come from a natural source, so I assume there is an artifical source but didn't really see anything like that in the video.

[Temujin]

From here under "Design and geography of Rama"

Both ends of Rama are lit by six giant trenches (three in the northern hemisphere and three in the south), equidistantly placed around the cylinder, effectively functioning as giant strip lighting.

[Swindle1984]

Speaking of lighting, as the mirrors opened for night time and closed again for day time, how would the "sunrise" and "sunset" appear in the cylinder? Would there be a visible terminator inside the cylinder as the mirrors moved? What angle would the light mostly come from? And assuming roughly current technology, how long would it take for the mirrors to change from fully-open position for night to normal day time position?

I'm guessing daybreak and nightfall are going to be somewhat more abrupt than on the earth, since there'd be no twilight.

[Iosef Cross]

So this is something we could build today, if we actually gave a shit about space colonization.

In 1975 in the Stanford Torus project it was estimated that a space colony of 10,000 would cost about 180 billion 1975 dollars, with is ~800 billion in today's dollars. Hence, the cost per person would be 80 million dollars.

For comparison, the average american has 200 thousand dollars of invested capital (including his housing, the investment in factory and office space, equipment, etc). About 0.25% of the amount needed for a space habitat dweller.

Hence, it is not because people don't give a shit about space colonization that they didn't build space colonies yet, it is because these thing are really expensive.

Space habitats are a extremely inefficient way of space colonization in terms of costs, simply because you have to manufacture everything, from the air, earth, structure to the actual city inside the colony.

For example, if my memory is correct, the Stanford Torus would have a mass of 10 million tons, and the city inside the space habitat would have 350,000 tons. That means that you need 30 tons of mass for every ton of building you need to shelter inside it.

[Iosef Cross]

Second to the Space Settlements: A Design Study, NASA in cooperation with Stanford university, estimated the cost of the 10,000 inhabitants space settlement was:

Through completion of the first colony the program would cost $196.9 billion, excluding costs directly related to SSPS's and more colonies (columns 1 and 5 of table 6-9). An additional $14.7 billion would be needed to prepare for production of the demonstration SSPS's (columns 3 and 4 of table 6-9) which would cost $21.7 billion more than the value of the electricity they produce.

source: http://www.nas.nasa.gov/Services/Educat ... 6.html#EST

The 196.9 billion in 1975 dollars, which are $776.41 billion in 2009 dollars, or the GDP of the state of New York, are a awful amount of money to spend on 10,000 people.