For a satellite revolving around the earth

Explanation

A rocket is a reaction engine in which the exhaust gases escaping from its back propel it forward. A launch vehicle consisting of a single- stage rocket would give a satellite only a vertically upward thrust. By the time all the rocket fuel used up, the satellite attains a maximum speed. The higher this speed, the more will be the maximum height attained by the satellite. Then, the gravity will bring it to ground. But if the speed attained is high enough. the satellite 'escapes' the Earth's gravity and drifts into space. In any case, it would not become a satellite of the Earth. Therefore, a single stage rocket is of no use and lower thrust by the second-stage gives the correct horizontal velocity to the satellite to put it into a stable circular orbit. This velocity is determined by no altitude of the satellite. Hence, a minimum two-stage rocket is necessary to launch a satellite into an orbit around the Earth.
Therefore, a single-stage rocket is of no use.
Using a two-stage rocket, the empty first-stage is deteched and the remaining rocket vehicle is rotatedd through `90^(@). Then a controlled and lower thrust by the second-stage gives the correct horizontal velocity to the satellite to put it into a stable circular. This velocity is determined by the altitude of the satellite. Hence a minimum two-stage rocket is necessary to lunch a satelite into an orbit around the Earth.