Vacuum Aiships

--- In spacesettlers, Ian Woollard wrote:

> Magnetic pressure is usually about 50 tonnes per square metre
> of magnetic pole- i.e. about 5 atmospheres; you might get a
> few times more with superconductors.
>
> So I doubt this would work very well; it would crush at about
> 50m depth or so.

That's cool, and something I hadn't thought of: resisting pressure with magnetic repulsion. But in my example, I'm not relying on that but instead on the kinetic energy of mass in motion. 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).

> You're nearly always better off using conventional materials
> wherever possible when you have to carry static loads. They've
> been shown to work down to a few kilometres, and they're much
> cheaper.

And for deep sea work that's fine, because you can be as heavy as you like. But an airship? That needs to be light.

Though now you've got me thinking: magnetic repulsion to to hold the vacuum chamber's shape, and resist the crush of atmosphere? I wouldn't call it "a repulsive airship," though. Bad marketing.