Kepler deduced three laws on the basis of various astronomical analysis which explains the understanding of analysis for planetary motion around Sun. The same analysis and these Kepler’s laws are also valid for satellite motion around a planet as while analyzing satellite motion around a planet we ignore gravitational forces by other planets on a satellite.
Kepler’s First Law: This is called the Law of Orbits. The law states that the planets revolve around the Sun in elliptical orbits with the Sun located at one of the foci of the elliptical trajectory. Watch the video below for understanding this law:
Kepler’s Second Law: This is called Law of Areas. The law states that the rate of the sweeping area by the position vector of the planet with respect to the Sun per unit time remains constant. This can be deduced by the law of conservation of angular momentum. Watch the video below for understanding this law:
Kepler’s Third Law: This is called Law of Periods. The law states that the square of the Time Period of the orbit of a planet is directly proportional to the cube of the semi-major axis of the elliptical orbit of the planet. Watch the video below for understanding this law: