really ? i thought it does . don ' t really play ranked enough to be sure tho <| sep |> you tried . i guess <| sep |> To prevent asymmetry of thrust . If one booster runs out of fuel a little before another you have a big control problem all of a sudden . It ' s easier to separate them slightly before burn out , so you don ' t have to worry about the control issues of the engines spooling down in thrust . Plus you get more positive separation as they thrust away . The Soyuz is an interesting collection of design choices from an era when rocketry was young and many of the things we take for granted today were difficult . For example , stage separation is always a tricky moment , because you need to wait until the thrust from the first stage cuts off , then you need to separate the stages in freefall very carefully , then you need to ignite the second stage . Failures in staging have caused several losses , especially in the early phases of development of rockets . SpaceX lost one of its first Falcon 1 launches when the first stage bumped into the 2 nd during separation due to a slight excess rotation , the 2 nd stage later failed . The Soyuz avoids those problems entirely by lighting the 2 nd stage while the first is still running . Instead of a solid interstage section there ' s an open grid , as the 1 st stage trails off in thrust the 2 nd stage lights up while still attached , then disconnects from the 1 st stage and pulls away . A brute force way of solving some of the complex problems involved but one that has worked for nearly 60 years .