A satellite is a small body which revolves around a planet. For example, moon is the satellite of the earth because it revolves around it. Satellites always revolve around the planets in closed elliptical paths. The closed elliptical path of a satellite around a planet is called its orbit.
Types of Satellites
Satellites may be natural or man-made. Natural satellites are those natural bodies which revolve around a planet. For example, moon is the natural satellite of earth. If however a man-made object is made to revolve around the earth, it is called artificial satellite. For example, Aryabhatta, Bhaskara, Rohini, Insat-1B, IRS-1A are artificial satellites because these satellites are placed in their orbits around the earth by human beings.
Principle of Satellite Launch
The principle involved in the launch of artificial satellites can be understand by assuming that you are standing on the top of a high tower and a stone is thrown by you parallel to earth with a certain speed. This stone will hit the earth at point A following a parabolic path. Now, throw the stone with greater velocity. The stone will now hit the earth at point B but after covering a longer distance. If you keep increasing the velocity of stone, it will hit the earth covering longer and longer distances and ultimately it will start revolving round the earth continuously without falling on the earth. The minimum velocity which is required to launch an artificial satellite in orbit around the earth is called orbital velocity It should be noted that the required minimum orbital velocity for an artificial satellite to place it in the orbit around the earth is about 8 km/s. The time taken by an artificial satellite to complete its one revolution around the earth is called time period.
Test Your Understanding and Answer These Questions:
- What is the meaning of satellites?
- What is definition of orbits?
- What are types of satellites?
- What is definition of orbital velocity?
- What is definition of time period?
- What are artificial satellites? Give examples.
- What are artificial satellites? Give examples.