In order to overcome the force of gravity and bring the spacecraft into Earth orbit, the rocket must fly at a speed of not less than 8 kilometers per second. This is the first cosmic velocity. The device, which reported the first space velocity, after separation from the Earth becomes an artificial satellite that is moving around the planet in a circular orbit. If the device to inform a speed less than the first space, then it will move on a trajectory that intersects a surface of the globe. In other words, it will fall to the Ground.
The shells A and B reported rate lower than the first space - they fall to the Ground;
the C shell, whereby said first space velocity will come to a circular orbit
But for such a flight, you need a lot of fuel. 3A a couple of minutes jet engine eats his whole railroad tank car, and in order to give the rocket the necessary acceleration requires a huge train fuel.
Gas stations in space there, so you have all of the fuel to take with you.
Tanks with fuel very large and heavy. When tanks are empty, they become unnecessary burden for missiles. Scientists have invented a way to get rid of unnecessary weight. The rocket is going as a designer and consists of several levels, or degrees. Each stage has its own engine and its fuel.
The first step is heavier than all. Here is the powerful engine and more fuel. It should move the rocket and give it the necessary acceleration. When the fuel of the first stage is used up, it is detached from the rocket and falls to the ground, the rocket becomes easier, and she did not need to spend extra fuel for transportation of empty tanks.
Included with the engines of the second stage which is less than the first, because it needs to spend less energy on the ascent of the spacecraft. When tanks of fuel will be wasted, and this step will leave us" from the rocket. Then will come into effect in the third, the fourth...
After work last stage of the spacecraft is in orbit. He can fly around the Earth for a very long time without any fuel.
Using such missiles go flying astronauts, satellites, interplanetary automatic station.
Did you know that...
The first space velocity depends on the mass of the heavenly body. For mercury, the mass of which is 20 times smaller than the Earth, it is equal to 3.5 kilometers per second, and for Jupiter, the weight of which is more Land mass in 318 times - almost 42 kilometers per second!