And another TIL from reading the comments on the video: "Question: Are inertial forces required, and incorporated into the designs of rockets, in order to keep

And another TIL from reading the comments on the video: "Question: Are inertial forces required, and incorporated into the designs of rockets, in order to keep liquid fuel at the bottom of each tank?" Reply: "They are in constant acceleration except when staging or after a shutdown before a re-start. They use ullage motors to accelerate the rocket just enough to settle the fuel (either small solid rockets or reaction thrusters) when they are in zero g." Reply 2: "Apart from Ullage Motors you can also do "Hot Staging" where you light the next Stage while the current one is still burning. That's why a lot of Russian Rockets don't have this open Interstage Sections where you can see the Engines instead of Interstage Fairings." https://en.wikipedia.org/wiki/Ullage_motor https://en.wikipedia.org/wiki/Ullage_motor