Why launch a satellite?

It is mainly used to observe the distribution and movement law of the atmosphere and clouds and forecast the weather. 70% of the earth's surface is ocean, and it is also very useful to observe information such as islands, fish, pollution and tides in the ocean through ocean satellites. Resource satellites are mainly used to observe information such as forests, deserts, farmland, villages, cities and rivers on land, and can also be used for resource investigation, urban planning, disaster prevention and mitigation, etc.

Secondly, satellites can also be used for communication. Compared with ordinary terrestrial communication, satellite communication has the advantages of large communication capacity, wide coverage, long communication distance, high reliability, good flexibility and low cost. Communication satellites generally adopt geostationary orbit, so they are always located somewhere above the equator of the earth. At present, communication satellites have entered a quite mature application stage, and their applications are increasingly extensive, such as transmitting telephone, telegraph, TV, newspaper, fax, voice broadcast, time scale, data, video conference and so on. Communication satellites are also used in international, domestic and military communication services, and regional communication and satellite-to-satellite communication are also carried out. Satellite communication technology has a strong military color and has an absolute advantage in strategic communication and tactical communication.