FWIW, once one of the members of a Klemperer Rosette loses its perfect
geometric position with respect to the others the "flying off in all
directions" happens very quickly and it's only a few orbital periods
before it is clearly destabilized. In the fleet of worlds
possibly-canon series of books, it is implied that the planetary
drives do provide active stabilization. I've never really liked
Rosettes or Ringworlds within the 3I universe because they shouldn't
be stable without active control, but then again the Regina planetary
and moon system as described in Book 6: Scouts as well as the T5
version of that system are both dynamically unstable as well. In the
T5 variant, Regina orbits too far from Assiniboia and will be
perturbed out of its orbit and into solar orbit and in the Book 6
version the inner moons rapidly destabilize each other: they're quite
massive and not in a MMR. So the existence of planetary drives might
actually be in heavy use throughout the Imperium.

On Fri, May 1, 2020 at 10:44 AM Jonathan Clark <xxxxxx@att.net> wrote:
>
> Phil Pugliese asked:
>
> >     And that's the big mystery of the one, or ones, that G'father,
> >     or his clones, created. Just how did he get them to be stable?
>
> Active controls. Some perturbation occurs (extra-solar comet, alignment
> of nearby stars causes a slight extra gravitic pull in some direction,
> gas giant alignment in outer system, or whatever), and a million years
> later you have planets flying off in all directions.
>
> So you leave massive grav plates (or handwavium engines) built into the
> cores of the planets forming the rosette. These sense that things are
> getting out of balance and nudge them back in again ASAP.
>
> By the time you have a tech level capable of moving planets into a
> rosette configuration, it should be easy enough to keep them there.
> Even Niven's Ringworld had huge great engines on the rim walls to
> provide this level of control.
>
> I speculate that a Banks Orbital would not suffer from the instability
> problems of a Ringworld or Rosette. (And if it did, the same answer
> applies). Corrections welcome.
>
> Question for anyone who still remembers how to do the math: given a
> Banks Orbital of 3 million kilometers diameter, and spinning once every
> 24 hours (so providing Earth-level gravity) , how much Coriolis force
> would the inhabitants experience? (Again, easy enough to compensate for
> this with Culture-level technology: bury grav plates in the ground to
> pull opposite the spin).
>
> >     But then it was 'The Ancients' wasn't it?
>
> Or someone that one or more of 'The Ancients' took a dislike to... :-)
>
> Jonathan
>
> -----
> The Traveller Mailing List
> Archives at http://archives.simplelists.com/tml
> Report problems to xxxxxx@simplelists.com
> To unsubscribe from this list please go to
> http://www.simplelists.com/confirm.php?u=wkJZDVdDoS21PvuTrsXSMsmho7pwDsoN