Okay kiddo, so imagine you have a toy car that you want to make go faster. You know how sometimes you push the car to make it go? A booster engine is kind of like that. It gives an extra push to something that is already moving to make it go even faster!
In space, booster engines are used to help big spacecrafts go further away from Earth. They're like really big and powerful rockets that add extra speed and push the spacecraft farther and faster.
Just like how you need more energy to push your toy car up a hill, booster engines are needed to help spacecrafts travel further into space where the gravity of Earth is weaker. This way, they can explore other planets or go to space stations.
Booster engines are a really important part of space travel because they help us go further and explore more of the universe!