Sputnik, a scientific and technological marvel, has been operating silently in the Earth's orbit and performing various important tasks. Whether it is communication, meteorological observation, navigation, scientific research and exploration, they all play a vital role. They are not only the most launched, the most widely used, and the fastest developing spacecraft among the spacecraft, but also account for more than ninety percent of the total number of spacecraft launches.
There are various orbits of artificial satellites, including low, medium and high orbits, geosynchronous orbits, geostationary orbits, sun-synchronous orbits, large elliptical orbits and polar orbits.
Satellites can be classified according to different criteria, and here are a few common ways to classify them:
a.Classified by running track
Low-orbit satellitesThe orbital altitude is generally between 200-2000 kilometers, and it is mainly used for communications, earth observation and meteorological observation.
Medium- and high-orbit satellitesThe orbit altitude is generally between 2,000-36,000 kilometers, including geosynchronous orbit and geostationary orbit, etc., which are mainly used for communication, broadcasting, meteorological observation and navigation.
Sun-synchronous orbit satellites: The orbital plane maintains a fixed angle with the sun, which is mainly used for meteorological observation, earth resource exploration and scientific experiments.
Polar-orbiting satellites: The orbital plane passes through the poles of the earth, and is mainly used for meteorological observation, earth resource exploration and scientific experiments.
b.Categorized by use
Communication satellites: Used to provide **, television, radio, and Internet services worldwide.
Meteorological satellites: It is used to monitor meteorological elements such as clouds, temperature, humidity and wind direction in the atmosphere to provide accurate meteorological data.
Navigation satellites: Used to provide global positioning services, such as GPS in the United States, GLONASS in Russia, Galileo in Europe, etc.
Earth Resources Satellite: It is used to monitor the distribution and change of resources on the earth's surface, such as land resources, water resources, mineral resources, etc.
Scientific satellites: It is used for scientific experiments and research in space physics, astrophysics, geophysics, etc.
c.Classification by launch mechanism
Satellites launched by the state: Satellites launched by ** or state agencies, such as China's Long March series satellites, US National Reconnaissance Bureau satellites, etc.
Satellites launched by commercial companies: Satellites launched by commercial companies, such as SpaceX's StarLink satellite, OneWeb's Global Internet Satellite, etc.
Each track has its own unique characteristics and applications. For example, satellites in geosynchronous orbit have the same rotation period as the Earth, making them appear as if they were stationary to observers from the ground.
Such orbits are commonly used for communications, broadcasting, and meteorological satellites. The sun-synchronous orbit and polar orbit are often used for meteorological observation, earth resource exploration and reconnaissance missions because of their special operation mode and coverage, respectively.
According to their uses, artificial satellites are mainly divided into scientific satellites, technical test satellites and application satellites.
Scientific satellites are mainly used for space physics and astronomical research, technical test satellites are used to test new space technologies, and application satellites directly serve national economic and military needs, such as communications, meteorology, and navigation.
Sputniks are very versatile and cover almost every aspect of human life. Here are its main uses:
Communications: Communications satellites are key to providing **, television, radio, and Internet services on a global scale. They enable people to communicate at any location by receiving and signaling, enabling remote transmission and data exchange.
Weather forecasting: Meteorological satellites can monitor meteorological elements such as clouds, temperature, humidity, and wind direction in the atmosphere, providing accurate meteorological data for weather forecasting.
Earth observation: These satellites are capable of monitoring changes in the Earth's surface, including the use of natural resources, geological changes, environmental monitoring, etc. The high-resolution satellite imagery they provide has a wide range of applications in areas such as agricultural assessment and urban planning.
Navigation and positioning: Global Positioning System (GPS) satellites are a key component of navigation and positioning. By providing precise time and location information, they allow people to accurately navigate, map and navigate across the globe.
Scientific research: Scientific satellites are used to conduct cosmic and astrophysical research and explore the mysteries of the universe. These satellites can study a planet's atmosphere, radiation belts, magnetosphere, cosmic rays, solar radiation, etc., and can observe other stars.
Military applications: Military satellites play an important role in missions such as military communications, intelligence gathering, and surveillance.
Although there are many types of satellites and their different uses, there are also many commonalities between them.
First, their flight follows Kepler's three laws, which are the basic laws of celestial motion.
Second, no matter what kind of satellite it is, it needs to be launched into space by a launch vehicle or space shuttle to gain the necessary orbital speed to begin its journey around the Earth.
Third, although satellites are used for different purposes, their system composition includes two parts: public and private systems.
Utility systems include structural, thermal, attitude and orbit control, data management, radio measurement and control, and power supply systems.
Specialized systems, depending on the mission, are called "payloads" for specific tasks.
The impact of artificial satellites on society is far-reaching and diverse, mainly reflected in the following aspects:
Improvements in global communications: Artificial satellites have made global communications easier and more efficient. Through satellite communication technology, people can communicate and transmit information over long distances across geographical limitations, contributing to the process of globalization.
The development of radio and television: The advent of satellite radio and television has made it possible for viewers around the world to receive and receive a variety of programs and content in real time. This not only enriches people's entertainment life, but also promotes cultural exchange and dissemination.
Improved accuracy of weather forecasts: The accuracy and timeliness of weather forecasts have been significantly improved through real-time monitoring and data collection by meteorological satellites. This is important in agriculture, transportation, energy and other fields, helping to reduce the impact of natural disasters and ensure the safety of people's lives and property.
Earth Observation and Environmental Protection: Earth observation satellites provide a wealth of data on the Earth's surface and environment, which helps scientists and research institutions in environmental monitoring, resource management, and climate change research. This is important for promoting sustainable development and protecting the environment.
Convenience of navigation and positioning: The wide application of satellite navigation systems such as global positioning system (GPS) makes people's travel and logistics transportation more convenient and efficient. This has had a positive impact on the transportation, logistics, tourism and other fields of modern society.
Advancement of scientific research: Artificial satellites provide a unique platform and tool for scientific research, which helps scientists to carry out research work in the fields of space exploration, astrophysical research, etc. This is of great significance for promoting the progress of human science and technology and expanding the boundaries of human knowledge.
Sputnik is the crystallization of science and technology and a symbol of human wisdom and courage. They operate silently in the silence of space, providing countless conveniences and services to humans. Whether it is to explore the mysteries of the universe or to serve the daily life of human beings, artificial satellites play an irreplaceable role.