Driving the Rocket

If you have ever fallen off a bicycle, or bumped your head, or simply walked a single step, you have experienced one of the most important laws about the way things move.

It was announced by the great scientist, Sir Isaac Newton, three centuries ago and says that action and reaction are equal and opposite. If we push against something, it will push back. The wheels of a car push against the road. The propeller of a ship presses against the water. When we walk, our feet press against the floor or the pavement. When we fire a rifle it is not only the bullet which is pushed. The rifle kicks back against our shoulder.

When we travel out beyond the earth's atmosphere into space, there is nothing to push against, and all the time the earth's gravity, acting like a great magnet, tries to pull us back. How can we drive our rocket through empty space?

The answer is really quite a simple one. Two things are needed. A supply of fuel is the first. But the fuel will not burn without air, and there is no air in outer space, so we must carry a supply of air in the rocket.

There are several kinds of fuel which can be used. One is alcohol, with liquid oxygen to provide the air to burn it. Another is hydrogen peroxide, which contains oxygen and also water. There is another important thing about the rocket. It will travel more swiftly in space than through air, for there is less resistance. The rocket speeds through space on its own gases.