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.

Astronauts live and work on the International Space Station, a science lab that orbits the Earth. They have to strap themselves down to sleep so they don't float away! On board, they run experiments, repair equipment, and study how living in space changes the human body.

Before anyone can become an astronaut, they train for years. They learn to fly, to fix machines, to speak more than one language, and they practise their tasks underwater in giant pools — because floating in water feels a little like floating in space.