Flight sequence

Following the synchronised countdown which lasts a few minutes, the launcher lifts-off from its launch pad.

The launcher starts rising vertically to get out of the dense layers of the atmosphere as quickly as possible, given that, at very high speeds, the resistance of the air is overwhelmingly strong. The first stage, which is the biggest one, thus carries the whole launcher to the Space vacuum before it reaches too high a speed. The target altitude is approximately 200 km.
The launcher then gradually takes a horizontal trajectory. The violently expelled gas enables the launcher to reach a considerable speed of at least 28,000 km/h. At this stage, the fairing, which is no longer needed, is jettisoned.

During the last minutes of flight, the launcher stops climbing. When the required speed has been achieved, the engine is extinguished and the launcher frees its payload while imparting the same speed to it. The satellite henceforth depends on its own resources and this marks the ‘end of the launcher mission’.

Throughout the mission, the launcher’s evolution is tracked from the ground by the launch base, but also by other tracking stations depending on its trajectory.

Engineers are kept informed by telemetry transmitted automatically by the launcher.

*This is an example of a nominal sequence for the generic version of Ariane 5 placing two satellites on a geostationary transfer orbit. Source : cnes.fr