Rocket trivia: how did the countdown happen?

Rocket trivia: how did the countdown happen?

During the launch of the space rocket, we can hear “… The 5, 4, 3, 2, 1 “countdown…
What is the rocket's advance in space without air?

What is the rocket’s advance in space without air?

The rocket can send the spacecraft into orbit around the earth, and it can also send satellites and…