(09-17-2015, 02:06 PM)hanelyp Wrote: Note that the cylinders are operated in counter-rotating pairs to counter the instability of rotating on their long axis.
Yes, that's the standard O'Neill design. But you do sometimes see single-cylinder designs, like Kalpana One. (The first version of Kalpana One was in fact unstable, but then we revised it and made it short enough to be stable with flat endcaps. If I were to do it again today, I would use inverted endcaps, which would allow us to make it considerably longer.)
Joe Strout
Lead Developer, High Frontier