The object revolves around the planet are called satellite. Natural satellite is made by Nature at the time of earth birth. It is the made up of rocks ,dust, gaseous. Their lifetime is too long. It not completely work on man made principles, it works on Nature principles.Eg, Moon. Artificial satellite made by human for their profit. It made up of elements which are know to human. It lifetime is small. It works on principles which are known to human. Eg., INSAT