Vacuum Aiships

Heh. This line of discussion is taking me back to a fierce, weeks-long online debate I had with someone once. I'd made the point that one advantage of O'Neill habitats over habitats on the moon was that the former could rotate to provide a full 1-G of gravity, while the latter could not. Someone popped up to argue that a lunar settlement could be built like a great big maglev on a banking track, and began describing his design in some detail. I allowed that something like that on the scale of a small gymnasium might be built on the moon and might even be useful for someone about to be rotated back to Earth. But I doubted that such a thing could be built on the scale of an O'Neill habitat (an independent settlement of 10,000 or more, growing its own food, etc.).

I had said that one advantage the rotating O'Neill hab would have over same on lunar surface is that the former would not require bearings for any significant load, while the latter would require relatively massive support bearings. He then angrily argued that his design didn't need any bearings at all. I told him that since we was comparing it to a maglev, this meant he was taking about magnetic bearings, whether he realized it or not.

Regards,

Mike Combs

On 11 May 2012 17:41, sailor.barsoom > wrote:

> The magnetic stuff is just to get the mass moving, serve as a frictionless
> bearing, and keep it moving. It is the outward pressure of mass in motion
> that counters the inward pressure of the sea (or atmosphere, in the airship
> case).

The outward pressure of the moving mass has to act through the bearing, and
the bearing is magnetic, which has the limitation I mentioned.

-Ian Woollard