e
Space Colony Form Factors, Part 2: O'Neill Cylinders
Tubey or not tubey, that is the question
For forming a free-floating space colony, the Bernal Sphere we looked at earlier solved the problem of gravity, but didn't solve the problem of being, like, totally lame. In an effort to not be totally lame, in 1976 American physicist Gerard K. O'Neill proposed an alternate design comprised of two huge cylinders.
Enter a caption (optional)I'm American, so I assumed those pods on the outer ring are jail cells; but I read that they're actually supposed to be farming pods.
These O'Neill Cylinders would each be two miles in diameter and 20 miles long. They would be side-by-side but not directly touching, and would be connected at their ends via rods. Each cylinder would spin to provide internal gravity via centrifugal force, and they would spin in opposite directions. The thinking is that this would keep the collective structure balanced, whereas just one cylinder spinning would cause the craft to veer out of position.
That's the official reason given for having two cylinders, but the wise among us can see the real benefit. Having two cylinders gives the thousands of people living inside each tube a perfect way to discriminate against each other. People in Cylinder 1 could think of people in Cylinder 2 as a bunch of uneducated hicks, and give that cylinder a nickname like the Rube Tube. The people in Cylinder 2 could think of the people in Cylinder 1 as a bunch of pseudointellectual jackasses (though they would not be able to think of a clever nickname for Cylinder 1 because they are a bunch of uneducated hicks).
Enter a caption (optional)The other brilliant part of this design is the fact it involves huge cylinders. NASA is comprised primarily of men, and certainly was in the 1970s, and we men love funding huge cylinders. We really enjoy building submarines, blimps and foot-long hero sandwiches. No one can say why.
But the weird part about O'Neill's design is how sunlight is admitted into the interior. Each cylinder is divided into six stripes running lengthwise; in alternating fashion, three of these stripes are habitable land, while the other three are windows to admit sunlight. I call it weird because if the cylinders are constantly spinning, won't that create a potentially-irritating strobe-light effect as the sun whips around and around? If each cylinder were a 20-mile long nightclub I'd call it efficient, but in most of the renderings it looks pretty parksy.
Enter a caption (optional)One alternative O'Neill Cylinder design does away with the lengthwise stripes, and instead covers the entire interior with land and has a huge window in one end of each cylinder. With this design you keep the station oriented so that the sun stays put in this end window and appears stationary. But this might suck if you lived at the other end of the cylinder; you'd always feel like you were in the end of a tunnel with a train coming towards you.
Enter a caption (optional)
Enter a caption (optional)By the way, these cylinders are so large that it's believed they can actually have clouds and their own weather systems inside.
Enter a caption (optional)
Enter a caption (optional)So while I am inexplicably drawn to the long, shaftlike shape, I have to dismiss this design unless someone can explain to me how to get rid of the club-lighting effect.
Next we'll look at a design that's a sort of hybrid of these first two concepts.
-
o2Favorite This
-
Q11Comment
Directory Company Profiles
Core77
Industrial Design
Resources
Industrial Design
Resources
-
Core77 Directory
Find the Best Industrial Design CompaniesGo -
Bould Design
BOULD DESIGN is a strategic partner for bringing highly functional, beautiful and successful product...
-
Doris DevDoris Dev is a New York and Hong Kong-based product development agency with a proven track record of...
-
Delve
We are a multidisciplinary product innovation and development firm that brings bold ideas to market....
-
aruliden
Aruliden is a global design agency born in 2006. We are a collection of people who care deeply about...
-
Artefact
Artefact is a strategy + design firm. Design is powerful. It determines how we experience life, and ...
-
Speck Design
Speck Design is a Silicon Valley product design and strategy consultancy. For twenty years Speck Des...
-
Sprout Studios
Sprout Studios is an award-winning, concept-to-launch design studio deeply rooted in technology and ...
K
{Welcome
Create a Core77 Account
Already have an account? Sign In
By creating a Core77 account you confirm that you accept the Terms of Use
K
Reset Password
Please enter your email and we will send an email to reset your password.
Comments
If I might add to the conversation. New materials and technologies from the 21st centuries will allow huge improvements over the original design:
They'd call Cylinder 1 "Manhattan"
Do you get seizure from the stroboscopic effect of the Sun lightning you up once every 24 hours???
Look at the size of those cylinders!
And lookup in wikipedia if you can't remember your physics lessons!
The centrifugal force is F=m.w^2.R
so w^2=(F/m)/R
w=sqrt((F/m)/R)
F/m is the acceleration. If you want to get an accelleration similar to Earth gravity (but actually I guess most people would want a smallest gravity, perhaps down to half Earth gravity), you take F/m=9.81;
With a radius R=500 m (that's only 3.14 km around, if you have six sectors, only 523 m wide!), you get w = sqrt(9.81/500) = 0.14 rd/s or 0.000371 rotations per minute. The inverse is 2691 minute per rotation, or 44 HOURS per rotation!
Is it still too fast a strobe for you???
The problem is actually to get a day cycle of 24 hours. would either have to reduce the radius for example, 145 m for 9.81 m/s^2, but this gives a very small cylinder.
Alternatively, you could have smaller windows, and use mirrors to project light during smaller periods. But you would want to do that synchronously for all the sections, because it would be no night if you had two lighted sections overhead.
0.14 rd/s = 1.33 rotation/minute, not 0.000371;
That's 2085 rotation per day! You'd need a radius of 3 million km to get a rotation per day!
Much like the alternative cylinder design with the window on the end, the ones with the windows along the sides are also pointed- long end- at the sun. The mirrors rotate with the windows, so since the mirrors are never occluded by anything, the reflected sunlight won't waver.
The shadows in the picture show the cylinders pointed at the sun. This is another reason the pairs of cylinders are counter rotating: the cylinders can be close enough that the mirrors don't hit the adjacent cylinder, and they interleave with the adjacent cylinder's mirrors as they rotate. Spinning the same direction, they would need to be even farther apart.
It would be easy to simulate night (and moving shadows) by having the mirrors rotate at a slightly different speed than the cylinders, but you'd need the mirrors to twist to point towards the windows too.
That's is the same concept of the alien vessel on Arthur C Clarke's Rendevous with Rama. If I remember well, on the book descriptions of the internal part of the cylinder, there were no windows, light was provided artificially through long lines (maybe led stripes or something...)
Note that the book predates the O'Neill cylinders by three years.
Also the ships in the book cannot depend on a given amount of sunlight- they start from far away from the sun to really close, so windows would, at first, be pretty useless, then would need to be tinted as they got closer.
Also note that even Skylab predated O'Neill cylinders and there's the neat video of an astronaut creating his own artificial gravity in it by running around its circumference.
I think the strobe effect would only happen if you were stationary while the tube spins. If you revolve with the tube, it would instead just look like the sun is orbiting the tube rapidly. Lots of long-cast shadows would be streaking from one side to another, over and over.
the tangential acceleration (artificial gravity)ratio is actually varies by the rotational frequency squared.... so if you got 3G at 24rpm, 1G would require about 14rpm ....
in short, the "G's" are the result of the radius multiplied by the angular velocity squared (in radians).
so if you wanted to cut the rotational speed in half, you would have to increase the diameter 4 times in order to keep the same "G's" (acceraltion)
another forgotten effect of objects on the outer edges of rotational masses is the coriolis effect.
Jason, that's exactly what I mean. Don't you think that would drive you nuts?
I suppose it depends on how quickly it rotates. The larger the space tube, the slower the rotation needed to reproduce 1G in the inside walls.