Rick Jones wrote:-polaris-a-cutaway.jpg

My recollection of viewing the youtube video was seeing four distinct
glowing circles on both ends of the first stage when it was tumbling
around doing its Roman Candle thing, which is what led me to believe
it was four parallel solids. Like say the sequence starting at ~02:15
if I'm still watching the same footage. Am I just seeing the nozzle
end each time when I see the four glowing circles?


I just rewatched it, and it looks like the four spots were on the same
end all the way through. There is a point where the flame coming out of
the top looks irregular in shape, but that could be either due to the
star-shaped central bore of the engine grain, or remnants of the top
dome of the engine after it ruptured. It looks like it started leaking
and then failed almost immediately after launch, as the black smoke that
engulfs the lower part of the stage just before the explosion seems to
come from the area at the top of the first stage.
Note that as it tumbles a lot more fire comes out of one end than the
other, and the end with the four nozzles is the one with the least fire
coming out of it, as the whole top dome has pretty much disintegrated,
leaving the top of the stage pretty much a open pipe.
That's even more noticeable on the failure that starts a 3:50.

I like how the film was reversed at ~05:15 with the speed limit sign
reading backwards

Hadn't caught that, but it is indeed. :-)


Pat