"Murray Anderson" wrote in message

The CG is way behind the CP at least until the SRB is close to burnout.
There isn't all that much weight up front. The specific gravity of a
Centaur
upper stage is something like .25 and the payload, including the payload
fairing, is even less dense. Even when the SRB is half burned the CG is 2
or
3 diameters behind the CP.

Is the CG really so far behind the CP - and for that long? Where do you get
that data from? Remember 51-L? They _appeared_ neutrally stable, to me, as
they flew from 73 seconds to destruct - for some of that time flying nose
forward into Vinf. Add on an upper stage and a "20 metric ton" CEV and I'd
guess that the CG is ahead of the CP.

Might be an interesting "extra credit" problem for someone ...

Jon