You can see yellow fire at the pointy end of the boosters for a moment as they swing round; is that some kind of separation thruster, or is it just that they're dipping into the main vehicle's exhaust stream?
Very cool. I'm interested in that 180 degree spin they do soon after lift off - is it to stabilise the rocket, or is there some other technical reason they perform that manoeuvre?
This question is one of the FAQ from here: https://geektimes.ru/post/275878/
google-translate:
Despite the fact that the missile from a distance it seems symmetrical, for management it has a clear "up", "down", "left" and "right". After starting the rocket should be developed in the so-called guidance plane. At Baikonur launch pad rotates, because in the 50's analogue systems are not able to so active spinning. On a more modern launch sites in Kourou on the "East" there is no need to do this, the rocket itself rotates. Depending on the position of the launch pad and launch trajectory angle of rotation may be different, according to the video to start at a very similar sun-synchronous orbit with an inclination of 98 ° to Kourou it turns out approximately 90 °, to the "East" in the region of 180 °
It's for the guidance system, it only pitches on one axis so they roll around to the correct heading before they pitch over. On the older Soyuz variants they physically rotated the launch pad. This is because the engine gimbal better in certain directions due to the design.
I'm not sure if other rockets do this, but I'd expect the Atlas V does due to the engine configuration. The Space Shuttle also did, but for aerodynamic reasons.
Yes, most rockets roll to correct launch azimuth before they pitch over a few degrees. After that they maintain zero angle of attack throughout the gravity turn.
https://www.youtube.com/watch?v=vHWDNrrfhnI