Rockets and Astronauts

To reach space, we need rockets. They burn fuel to push themselves upward with a huge force, fast enough to escape Earth's gravity. To break free of our planet, a rocket has to reach an astonishing speed of about 28,000 kilometres per hour — far faster than any aeroplane.

How does a rocket actually push against nothing? The secret is one of the great rules of science: for every action there is an equal and opposite reaction. A rocket burns fuel and blasts hot gas downwards out of its engines, and that pushing-down of gas pushes the whole rocket up. It does not need air to push against — which is why rockets work perfectly in empty space.

Rockets are built in sections called stages. As each stage runs out of fuel it drops away, making the rocket lighter so it can fly even faster into space. Most of a rocket on the launch pad is actually just fuel tanks — the part carrying the astronauts is a tiny piece right at the very top.