Satellite:-

A satellite is an object that orbits other objects in space. This includes natural satellites like the Moon and artificial satellites made by people. The term satellite came to be used after Galileo Galilei discovered the four main moons of Jupiter

Artificial Satellite:-

Artificial satellites have been put to a wide range of uses. Some satellites send and
receive television signals so that we can watch many television channels. If there are enough satellites in space, one television programme can be seen all over the world at the same time.

Weather satellites help scientists called meteorologists predict what the weather will be like. These satellites can save hundreds of lives by warning fishermen not to sail before a storm, and predicting when a hurricane will strike.

Some satellites take photographs of the Earth’s surface so that scientists can study changes in the world. This is how scientists know that glaciers that are millions of years old are melting because of global warming.

Some others are communication satellites that deal with telephone, fax, internet and computer communications.

How Satellite rotate in Orbit:-

Artificial satellites are given a definite path around the Earth. The Earth’s gravity
holds the satellite in a path called an orbit. There are several kinds of orbits.

One is Leo or Low Earth Orbit. A Leo satellite circles 160–480 kilometres (100–300 miles) above the Earth’s surface. It has to travel very fast to avoid being sucked back to the Earth by gravity. Leos travel at about 28,164 kilometres per hour (17,500 miles per hour) and can circle the Earth in less than two hours.

Medium Earth Orbit or Meo satellites are placed 9,656–19,312 kilometres (6,000–12,000 miles) above the Earth. They are often used for communications of all kinds. Geos or Geostationary Earth Orbit satellites circle the Earth in 24 hours, which is the time the Earth takes to rotate once on its axis.

So they seem to be fixed above one spot on the Earth. Geo satellites orbit 35,859 kilometres (22,282 miles) above the Earth. They carry television signals across the world, telephone calls between countries and internet messages. They also help predict the weather.

How does the satellite get into space?

A satellite is launched into space on a launch vehicle which is driven by a rocket
engine. There are special launch stations for satellites like Cape Canaveral in the USA, Baikonur in Kazakhstan, Kourou in French Guiana and Xichang in China.

To start with, launch stations were run by countries or national organizations. Nowadays there are large private companies that also run some launch stations and provide the service of launching a satellite on a commercial basis.

These launch stations must be far from human habitation so that the falling launch vehicle lands in water or on desolate land. Some satellites are launched from a portable platform on the Pacific Ocean.

The launch vehicle’s rockets carry the satellite into a temporary orbit. The rockets and the launch vehicle drop off. Then the satellite is ready to take off on its own motor. When it reaches its permanent orbit, the antennae and solar panels open up and the satellite starts sending and receiving signals.