Rick Jones wrote:

As I've gotten permission to share the diagram, and I happen to have a way to do so broadly:

ftp://netperf.org/polaris_1st_stage003.jpg

Now, that's _odd_.
The base looks like a oversized primer on a artillery shell cartridge.
I wonder if the little cone shaped chunk of propellant at the base gets
ignited from below and serves to keep water out of the nozzles till the
missile gets airborne and the main section of the grain ignites from the
top of the central bore, like is usual in a solid motor.
It also looks like some other type of fuel mixture is used near the base
and inside the grooves of the star-shaped bore.
The drawing doesn't show any details of the fluid injection system of
the nozzles though, nor where the freon for it is stored.

Pat