On Thu, 17 Feb 2011 09:30:09 EST, "Jonathan Thornburg [remove -animal
to reply]" wrote:

If you have separate rotating and non-rotating sections (as in, for
example, the movie "2010"), then yes, you need a rotating air-seal
between them. This takes a bit of effort for the engineers, but is
certainly possible.

A bigger problem than the pressure seal would be the need to
transfer control signals and power through the moving section.

Although... given the advancements in wireless technology, that
isn't as big a problem now as it used to be.