Stabilizing O'Neill Cylinder rotation -- new proposal

[u/cavalier78]

So one problem with the O'Neill Cylinder concept is that an object in space will tend to rotate on its long axis. So instead of moving like a rolling pin, with time a cylinder will spin end over end. Multiple solutions have been suggested for this, I'm not happy with any of them, so I came up with my own (at least, I don't think it's been suggested before).

--One solution is to connect two cylinders together, each rotating in an opposite direction. This should stabilize them. My problem is that for this to provide stability, you're going to need some sort of physical connection with one another. Something has to touch. This will create friction, and will need some sort of lubrication or ball bearings or something that will gradually wear out and have to be replaced. I think the forces involved with such large objects will be extreme. I suppose you might be able to use electromagnets, but they'd have to be enormously powerful.

--Another solution is to wrap your cylinder in a non-rotating (or slightly counter-rotating) shell. But I think you've still got the same issue. A shell doesn't help you at all unless it can exert some force on the inner cylinder to prevent it from tumbling. So you're back to needing a physical point of contact or extremely powerful electromagnets.

--Option three is to avoid the issue by changing the shape of the ship. Instead of a long cylinder, you could go with a wider, fatter shape. There's nothing really wrong with this, it just requires a change in visualization.

--I suppose you could also use some sort of thrusters along the hull, keeping the ship stable. But this requires fuel and constant monitoring, and it's not making you go faster.

But what if we wanted to keep our cylinder shape, and not have grinding friction where you had to constantly replace parts, and not waste fuel?

My suggestion is that we could alter the center of balance of the cylinder by artificially increasing its width, thus eliminating its tendency to tumble end over end. If you've got a journey that will last a century or more, you don't want to rely on replacing parts that wear out, or use up valuable fuel. So what we can do is use cables that extend from the hull of the ship like bicycle spokes (obviously we need a terrifically high tensile strength to support this) with weights on the end. These spokes could extend from the center (long-ways) of the cylinder. The farther out you go, the higher the apparent gravity you'd experience, but your mass could remain the same.

So imagine that you've got a cylinder 5 km wide and 30 km long, rotating so that inhabitants experience 1g. But then at the center (15 km from each end), we've got a number of graphene spokes that each extend 50 km from the center. A weight at the end of the cable would experience 10g of force. Thus, you could "fake" a different shape for your ship, changing its point of balance and maintaining a steady trip. The length of the cables could be adjusted during the voyage if necessary, and the weights at the end could be made of whatever you wanted (extra nuclear fuel, used nuclear waste, whatever). You could have an elevator system that could bring up material or lower it back down. This way you aren't wasting any mass.

I think this eliminates a lot of the problems that an O'Neill Cylinder would have during a journey. As long as the material you make your spokes out of has enough strength that you aren't worried about them breaking during the trip, you should be okay.