Revised rocket plume effect, test animation (no audio). After a lot of experimentation, I settled on this very simple effect as the most appropriate. It's mostly just a moving texture with a four-color ramp.

[NOTE (2022): this is NOT the final effect. I did a LOT of work trying to figure out a good aesthetically-matched effect for rocket plumes effects. This is obviously something we need a lot of for a space-technology series, and there's actually a fair amount of variety. And many aesthetic choices: more "realistic", more "cartoon", more "movie-expectation" (because Hollywood movie notion's of rocket plumes are rather different and much more showy than the real thing, which people often think looks "fake", because they've never seen the real thing)]