Hi Stephen

The Earth orbits around the solar system because the Sun, at the center of the solar system, exerts a gravitational pull on it, but at the same time the earth is moving at a great speed in the other direction.

Think of two extreme situations. If the Earth were not moving then the pull of the sun would make the Earth go straight in toward the Sun. And if the sun were not there, then the Earth would just travel in a straight line. But the result of the struggle between the sun pulling the earth inward, and the earth wanting to go in a straight line, is that the earth goes in a circle round the sun. If the Earth had just a little bit higher speed it could leave its orbit round the Sun, and if it had just a bit lower speed then it would spiral in.

In technical words, we have a balance between the gravitational force and the centripetal force.

To get a rocket into space, you have to make it go fast enough to escape the gravity of the Earth. This is done with immensely powerful engines. If it wasn't going fast enough, then a rocket would fall back to Earth. How you stop it blowing up is another matter. You have to have smart engineers to design it so that it is safe. A modern rocket is a pretty complicated thing!