What is the purpose of having a countdown during a rocket launch?
The countdown is primarily used to confirm that all systems are go before the rocket is ignited. It also provides a clearly defined moment in time when the launch will occur. As the countdown progresses, various checks and procedures are carried out to ensure that all systems are operating correctly. Once the countdown reaches zero, the rocket is ignited and the launch begins.
During a rocket launch, the countdown is a series of time checks and confirmation announcements that provide critical information for both the launch team and mission controllers. The countdown confirms the readiness of all systems, provides the opportunity to abort the mission if an issue is identified, and sets the exact time for ignition.

The countdown sequence typically starts several hours before lift-off, with the team checking various systems such as fuel levels, engine temperatures,