What's Going On In This SpaceX Rocket Video?

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John, former NASA spokesman at KSC here. That was a darn good analysis. The main reason they delay the leg deployment until the last second is to keep from burning the legs. I wish they'd describe how they navigate the booster with such precision - but that's likely their secret. As always, it is simply astounding. (I was also an AF pilot and WISH we had that kind of precision landing ability!)

One point you didn't mention, but i think fits very well into this discussion, especially adding to the whole point of flame expansion: You can see that at the beginning the engines produce these long orange flames. As the rocket goes up and air pressure falls, the flames expand. But then one more thing happens: the flames become less and less bright, until at some point you can see barely any flame at all. Just before stage separation there is only a black cloud of exhaust gas coming out of the engines. The boost back burn does not produce a visible flame either, again only a dark cloud. Reason: The engines are running fuel-rich. That means that the mixture rate between fuel and oxygen inside the engines is such that not enough oxygen is present to burn all the fuel. There are several reasons why that is done, and i don't want to start that explanation since it would make this comment 5 times longer. But the point is that there is unburnt kerosene and soot coming out of the engine, together with all the exhaust gasses. That is all the black stuff you can see when the engines are running at high altitude. (And also the stuff that causes the "jelly-fish effect" if the lighting is just right) When the engines are running at low altitude, the exhaust flow mixes with ambient air. This allows the fuel from the exhaust stream to react with oxygen from the ambient, and burn. This causes the bright orange flames you see behind the rocket. Or at least the largest part of those flames. But as the rocket rises up in altitude the air density drops, there is less and less oxygen available in the ambient air, and the flames dim down, until they eventually fade out and you only see the soot.

One thing you can certainly see is the Go-Pro fisheye lens view of Earth, making it look ridiculous. All the worlds a stage.

I like seeing this perspective view. I have been lucky enough to watch 14 shuttle launches while living in Titusville back in the late '80s & early '90s. Thanks.

So are you telling me that there was no cameraman physically hanging on the rocket filming all this? Dang... Technology!

I think these videos are very helpful for those less versed in spaceflight tech. You explained Falcon in a way that my mother would understand, and that's quite a feat!

You need to put out more videos like this!!! Your vibe is welcoming and The indepth explanations of what's going on without sounding arrogant or patronizing is what I appreciate the most.

This was a great explination of some things I knew, some things if didn't, and connecting them all together. Looking forward to more of this type of content!!!

Simplified without being "dumbed down". Precise explanations with awesome visual examples. As always, great job! Thank you JG and NSF for everything you provide!!

I have always said since I first saw Falcon 9 launch that nobody, not even Boeing/NASA with its many years of experience can produce the viewer experience like one gets from a SpaceX launch, the photography is second to none. Now you come along and blow that right out of the sky with more SpaceX photography. That was amazing footage thank you so much for showing it.

You did great explaining. I really appreciate it because we don't all know a lot about what is going on.

well done John. Been following falcon ( SpaceX ) for years , good explanations of flame color or shape at different levels of atmospheric pressure to no pressure

Great talk through, thanks Das and NSF team.

Loved that in-depth walk through, yes! With such amazing footage, as well! Thanks Das and NSF-Team!

I really enjoyed your commentary on this video. It was very informative and just really cool fun facts to know about all the workings of a take off and landing. Good job nerd. I've subscribed. Lol

Very nicely put together video with commentary and inserts.

Thanks John, can't get enough of the coverage from SpaceX.

One of the best NSF videos by far! Great explanation!

great break down of everything that happens , like the back drop to your video too from the Martian film, its the Hab. Very cool. Thanks for you commentary !