Tony M wrote:
The important question is why would there be a need for relatively
rotating sections? I, personally, cannot think of a good reason. I am
with Sylvia on this one; the entire ship would have to rotate as a
single hull.

Things that are more conveniently located in a non-rotating
(a.k.a. "despun") section:
* antennas to communicate with the Earth
* telescopes to observe the target planet
* docking adapters for any sub-spacecraft
* airlocks for any spacewalks
* possibly heat radiators that want to avoid direct sunlight
* Whipple shields against orbital debris (if you're in a high-debris
orbit, i.e., a low-to-moderate-altitude Earth orbit)

--
-- "Jonathan Thornburg [remove -animal to reply]"
Dept of Astronomy & IUCSS, Indiana University, Bloomington, Indiana, USA
"Washing one's hands of the conflict between the powerful and the
powerless means to side with the powerful, not to be neutral."
-- quote by Freire / poster by Oxfam