R-7 (rocket Family) - Korolev Cross

The Korolev cross is a visual effect observed in the smoke plumes of the R-7 series rockets during separation of the four liquid-fueled booster rockets attached to the core stage. As the boosters fall away from the rocket, they pitch over symmetrically due to aerodynamic forces acting on them, forming a cross shape behind the rocket. The effect is named after Sergey Korolev, who designed the R-7. When the rocket is launched into clear skies, the effect can be seen from the ground at the launch site.