Roscosmos published unique footage of the launch of the Soyuz launch vehicle. The images capture the engine flame – usually it is almost as blinding as the Sun, but this time photographers managed to reveal its hidden structure.
The secret is in the ultra-short exposure. The exhaust gas velocity from the nozzles reaches 2800 meters per second. Even with a standard exposure of 1/8000 of a second, the image blurs. Using an exposure of 1/32000 of a second allowed minimizing this effect and preserving detail.
The footage clearly shows transparent, almost invisible jet streams erupting from the nozzles. What is usually mistaken for the “structure of fire” is actually tongues of kerosene burning in the air. A second before that, the fuel was cooling the walls of the chambers and nozzles from the inside.
The obtained images provide a unique insight into the physics of engine operation and the processes occurring in fractions of a second after launch.