What are the Different Types of Satellites?
An artificial earth satellite refers to an unmanned spacecraft that orbits the earth and orbits more than one circle in space orbit. Referred to as artificial satellite. Artificial satellites are the most widely used and fastest-growing spacecraft. Mainly used in scientific detection and research, weather forecast, land resource survey, land use, regional planning, communication, tracking, navigation and other fields.
- Chinese name
- Artificial earth satellite
- English name
- satellite
- Short name
- Artificial satellite
- An artificial earth satellite refers to an unmanned spacecraft that orbits the earth and orbits more than one circle in space orbit. Referred to as artificial satellite. Artificial satellites are the most widely used and fastest-growing spacecraft. Mainly used in scientific detection and research, weather forecast, land resource survey, land use, regional planning, communication, tracking, navigation and other fields.
Basic introduction of artificial earth satellite
- To put it simply, artificial satellites are sent to space by giant multi-stage rockets with huge propulsion. The working principle of a multi-stage rocket is not complicated, that is, several single-line rockets are connected in series or in parallel to form a large rocket system. Each of these stages is a rocket that can work independently, and they complete the flight mission in stages. The first stage is the ignition of the first stage rocket. At this time, the entire rocket empties. When the propulsion of the first stage is exhausted, its bulky shell is immediately thrown away. Then the second stage starts to work. Part of the structural weight that has been useless, so that the entire rocket advances lightly, and then the shell of the second stage is thrown away, and the third stage is ignited ... Run faster. Until the end of the last stage of rocket work, the satellite mounted on the front end of the final stage rocket was put into earth orbit.
- Artificial earth satellite
- Artificial satellites generally consist of dedicated systems and support systems. Dedicated systems are systems that are directly related to the tasks performed by the satellite, and are also called payloads. The special system for applying satellites includes communication repeaters, remote sensors, navigation equipment, etc. according to the various uses of satellites. The dedicated system for scientific satellites is a variety of space physical detection, astronomical detection and other instruments. The special system for technical test satellites is a test equipment for various new principles, new technologies, new schemes, new instruments and new materials. The safeguard system refers to a system that guarantees the normal operation of satellites and dedicated systems in space, and is also called a service system. There are mainly structural systems, power systems, thermal control systems, attitude control and orbit control systems, and radio measurement and control systems. For return satellites, there is also a return landing system.
- The orbit of the artificial satellite depends on the mission requirements of the satellite, and it is divided into low orbit, medium or high orbit, geosynchronous orbit, geostationary orbit, solar synchronous orbit, large elliptical orbit and polar orbit. Artificial satellites fly around the earth at a high speed. Low orbit and medium orbit satellites can fly around the earth several to ten times a day. It is not restricted by territorial, airspace and geographical conditions, and has a broad field of vision. It can quickly exchange information with the ground, including the retransmission of ground information, and can also obtain a large amount of remote sensing information of the earth. The remote sensing area of an earth resource satellite image can reach tens of thousands of square kilometers.
- When the satellite's orbit reaches 35,800 kilometers and is flying in the same direction as the Earth's rotation over the Earth's equator, the satellite's rotation period around the Earth is exactly the same as the Earth's rotation period, and its relative position remains unchanged. This satellite appears to be hovering at a high altitude on the earth. It is called a geostationary satellite, or geostationary satellite for short. This satellite can realize uninterrupted information exchange between the satellite and the ground station, and greatly simplify the equipment of the ground station. . Most of the television broadcast and retransmission communications via satellites are accomplished by stationary communication satellites.
Classification of artificial earth satellites
- Artificial earth satellites can be divided into three categories according to their uses: scientific satellites, technical test satellites, and application satellites.
- (1) Scientific satellite
- Scientific satellites are satellites used for scientific exploration and research. They mainly include space physics detection satellites and astronomical satellites. They are used to study the upper atmosphere, the Earth's radiation zone, the Earth's magnetosphere, cosmic rays, solar radiation, and other satellites.
- Artificial earth satellite
- A technology test satellite is a satellite that performs new technology tests or tests for application satellites. There are many new principles, new materials, and new instruments in aerospace technology. Whether they can be used must be tested in the sky. The performance of a new satellite can only be launched into the sky to actually "exercise" it. Applications; humans must perform animal tests before going to heaven ... these are the missions of technology test satellites.
- (3) Application satellite
- Application satellites are satellites that directly serve human beings. They have the most types and the largest number, including communication satellites, meteorological satellites, reconnaissance satellites, navigation satellites, geodetic satellites, earth resource satellites, and interception satellites.
Functional classification of artificial earth satellites
- According to the spacecraft's orbital function, it can be classified into four categories: observation station, relay station, reference station and orbit weapon. Each category includes a variety of spacecraft.
Artificial earth satellite observatory
- The satellite is in orbit. For the earth, it stands tall and looks far away (large field of view). It is very advantageous to use it to observe the earth. In addition, since satellites are not subject to various interferences and influences from the atmosphere outside the earth s atmosphere, it is more advantageous to use them for astronomical observations than ground astronomical observation stations. Satellites belonging to this function have the following typical uses.
- Zhu Xuanxian's "Side by Side"
- reconnaissance satellite
- Among the various types of application satellites, the reconnaissance satellite was the earliest (launched in 1959), and the number of launches was also the largest. There are two types of reconnaissance satellites: photo reconnaissance and electronic reconnaissance satellites.
- Photo reconnaissance satellites are satellites that use optical equipment to take pictures of ground targets. Since the 1920s, about one-third of the military satellites launched by the former Soviet Union and the United States each year are used for various forms of photographic reconnaissance. They conduct general surveys and detailed investigations in low-Earth orbit.
- Electronic reconnaissance satellites use space-borne electronic equipment to intercept electromagnetic waves propagating in space and forward them to the ground. Through analysis and deciphering, they obtain enemy intelligence. The purpose of electronic reconnaissance is to determine the position and characteristic parameters of other aircraft, radar, and other systems, and to intercept other parties' radio and microwave communications. Electronic reconnaissance satellites accomplish these missions with radio detection and recording equipment.
- In short, the intelligence provided by reconnaissance satellites, whether for military strategic reconnaissance or military tactical reconnaissance, plays a role that cannot be ignored, and has provided a basis for the formulation of US and former Soviet Union policy and military actions. It is reported that nearly 70% of the military intelligence of the United States and the former Soviet Union comes from reconnaissance satellites.
- meteorological satellite
- Meteorological satellites use various meteorological remote sensors to receive and measure visible light radiation, infrared radiation and microwave radiation information from the earth, oceans and the atmosphere, and then convert them into electrical signals for transmission to ground receiving stations. Based on the collected information, the meteorologists obtain the global atmospheric temperature, humidity, wind and other meteorological data. Global weather data is available within a few hours to make long-term weather forecasts, determine the location and changes of typhoon centers, and forecast typhoons and other storms. Meteorological satellites have a great effect on ensuring the safety of navigation and aviation, and ensuring the production of agriculture, fisheries and animal husbandry.
- Meteorological satellites have evolved from simple meteorological experiments to comprehensive applications in multiple disciplines and fields; from low-orbit systems to high-orbit systems, a global meteorological satellite observation network has been formed. The application of meteorological satellites in military activities is also increasing. Some countries have established global military meteorological data collection systems to provide military units with real-time or non-real-time meteorological data.
- With the further development of aerospace technology, meteorological remote sensors will develop in a direction of diversification and high precision, greatly enriching the content of meteorological forecasts and improving the accuracy of forecasts. At the same time, the cloud images provided by meteorological satellites will also develop from static cloud images to dynamic cloud images, which will cause a major breakthrough in the development of meteorological satellites.
- Earth Resources Satellite
- Resource satellites are developed on the basis of reconnaissance satellites and meteorological satellites. The multi-spectral remote sensor loaded on the satellite is used to obtain the electromagnetic waves of various frequencies radiated and reflected by the ground target, and then transmitted it to the ground, and then processed into useful information about the earth's resources. They include ground and underground, land and sea, and so on.
- Earth resources satellites can be widely used: surveys of underground minerals, marine resources and groundwater sources; surveys of land resources, land use, and regional planning; surveys of rational planning and management of agriculture, forestry, animal husbandry, and water conservancy resources; forecasts of crop growth and harvest; Plant formation and landforms; examining and monitoring various natural disasters such as pests and diseases, forest fires, floods, etc .; environmental pollution, marine pollution; measuring water sources, snow sources; railways, highway route selection, port construction, coast use and management, urban planning . Earth resource satellites have significant economic value and potential military use.
- Ocean satellite
- The ocean is the cradle of life and the hometown of wind and rain. The close relationship between the ocean and human beings is gradually being recognized. The oceans control the water circulation and atmospheric movement in nature, dominate the regulation of the continental climate, and provide cheap transportation conditions and high-quality aquatic food. There are huge energy and mineral resources in the ocean.
- Artificial earth satellite
- The mission of Ocean Satellite is to forecast the marine environment, including the selection of the best routes for ocean-going vessels, the analysis of marine fisheries, the survey of offshore and coastal marine resources, the monitoring and surveillance of coastal and offshore marine environments, the forecast and early warning of catastrophic sea conditions, Law enforcement management, marine scientific research, and marine buoy, station, ship data transmission, maritime military activities, etc. Of course, the satellites used as observation stations are far more than the above. Early warning satellites, nuclear explosion detection satellites, and astronomical prediction satellites (such as the US "Hubble" space telescope) belong to this category. Although their functions have different focuses, the basic observation principles are similar.
Artificial earth satellite relay station
- A relay station is a satellite that amplifies and relays information in orbit. Specifically divided into two categories: one is used to transmit telephones, telegraphs, televisions, and data between remote locations on the ground; the other is used to transmit televisions and data between satellites and the ground. There are several types of such satellites:
- Communications satellite
- Compared with ordinary ground communication, the use of satellites has the following advantages: large communication capacity; wide coverage area; long communication distance; high reliability; good flexibility; low cost. Communication satellites generally use the geostationary orbit, which is equivalent to stationary in the sky. If there are 3 geostationary orbit satellites separated by 120 degrees from each other, global communications can be achieved except for parts of the Earth's poles.
- Communications satellites have been used for international, domestic and military communications, while regional communications and satellite-to-satellite communications have been carried out. Satellite communication technology has been given a strong military color, and it has absolute advantages in strategic communications and tactical communications. The international and domestic satellite communication systems of various countries have undertaken military communication tasks.
- Communication satellites have entered a fairly mature stage of practical application, especially with the development of geostationary orbit satellite communication technology, its applications are becoming increasingly widespread. It can be used to transmit telephone, telegram, television, newspaper, teletext, voice broadcast, time stamp, data, video conference and so on.
- Broadcast satellite
- A broadcasting satellite is a communication satellite mainly used for television broadcasting. This type of broadcasting satellite can rebroadcast or transmit television broadcast programs to the ground without any transit, and can be directly received by public groups or individuals, so it is also called live satellite. Ordinary home televisions can be equipped with a small-diameter antenna and set-top box to directly receive TV broadcasts from live satellites.
- Tracking and data relay satellite
- Tracking and data relay satellites are a major development in communications satellite technology. It uses satellites to track and measure the position of another satellite. The basic idea is to move the measurement and control stations on the earth to geosynchronous orbits to form a network of satellite-ground measurement and control systems. In this way, it is possible to greatly increase the tracking orbits of low-Earth orbit satellites, such as meteorological satellites, reconnaissance satellites, resource satellites, ocean satellites, and communication satellites, to improve the accuracy of orbit measurement and reduce the number of ground stations. In other words, the tracking and data relay satellite is to use the geosynchronous orbit satellite to realize the tracking and data relay of the low-orbit satellite by the ground measurement and control center.
- The development of tracking and data relay satellites will change the over-reliance of space activities on ground measurement and control, and at the same time overcome the difficulty of setting up ground stations abroad. Therefore, it has received widespread attention from all major space powers in the world. China is also actively developing this satellite technology.
- In addition to the above relay station satellite systems, countries have also developed and launched other types of dedicated communications satellites and radio amateur satellites, such as maritime satellites, satellite commercial systems, search and rescue systems ...
Artificial earth satellite reference station
- This satellite is the measurement reference point in orbit, so it is required to measure it very accurately. Satellites that fall into this category are:
- Navigation satellite
- This type of satellite sends out a pair of very stable radio waves. Maritime ships, underwater submarines, and moving bodies on land can determine their own position by receiving the radio wave signals emitted by the satellite. The use of navigation satellites for navigation is a major technological breakthrough in the history of aerospace. Satellites can cover the world for all-weather navigation, and the navigation accuracy is high.
- There are three types of satellite navigation and positioning: Dual-frequency Doppler velocimetry and positioning systems, such as the "Meridian" navigation satellite system in the United States. This type of satellite is a two-dimensional navigation and positioning system, which can only be used for underwater ships, and the positioning accuracy is 30 ~ 50m. The development of the "Meridian" satellite began in 1958 and began to be used in 1964. At first, it was used for the positioning of underwater nuclear submarines and has been discontinued; the navigation satellite global positioning system (GPS). Using pseudo-random code ranging, the system can perform all-weather, all-time, real-time 3D navigation and positioning with a positioning accuracy of less than 10, which is used for ships, aircraft, and land moving targets. The system requires 18 to 24 satellite networks. Russia also has two generations of navigation satellite systems similar to the United States; regional navigation and positioning systems. 3 stars (stationary orbit) provide a three-dimensional position. If two stars are launched, only two-dimensional positions can be provided. If users can provide their own height
- Can calculate the three-dimensional position. The system is characterized by being able to serve millions of users at the same time, without interference, and with good confidentiality.
- Geodetic satellite
- The principle of satellite geodesy is similar to that of satellite navigation. Since the measurement station on the ground is fixed, the measurement accuracy is higher than that of ship navigation and positioning. The accuracy achieved by satellite geodesy is dozens of times higher than that of conventional geodesy.
- Geodetic satellites can perform geodetic surveys, topographic surveys, map surveys, earth shape surveys, and gravity and
- Artificial earth satellite
- Satellite geodesy has been valued in military, scientific research, and civilian applications. Many countries have developed and launched geodesic satellite systems. The use of satellites for geodesy provides modern means for surveying and mapping, with short work cycles and high measurement accuracy, which greatly saves manpower, material and financial resources. In particular, to establish an accurate global geographic coordinate system or three-dimensional map, the use of satellite geodesy is the only feasible measurement method. With the continuous improvement of scientific and technological level, the application of geodesic satellites is becoming increasingly widespread. For example, people use geodesic satellites to measure crustal movements to monitor and predict earthquakes.
- There are active and passive geodetic satellites, and triangulation, laser ranging, and Doppler systems can be used to achieve geodesic purposes.
Artificial earth satellite orbit weapon
- This is an aggressive offensive spacecraft with functions of space defense and space attack. It mainly includes:
- Intercept satellite
- Satellites approach orbit as a weapon to identify and destroy enemy space systems. Such satellites are called anti-satellite satellites. There are many ways to intercept anti-satellite satellites. The main methods are: making the intercepting satellite meet the target satellite in space and then exploding to destroy the target; launching anti-satellite weapons from the intercepting satellite, such as laser, particle and microwave, directed high-energy beam emission Weapons; intercepting satellites accelerate with small rocket boosters carried by them and collide with the target satellites; try to make the target satellites incapable of working, such as using nuclear radiation to destroy the circuits and structures of the target satellites, and spraying materials on the target satellite camera lens, and many more.
- As early as the late 1950s, the United States and the former Soviet Union began studying interception satellites. Russia has mastered the technology of intercepting satellites below 1000km, and the United States also successfully conducted on-orbit anti-satellite tests in the 1990s.
- Orbital bombing system
- Orbital bombing system is a space-to-ground offensive weapon. Its mission is to deploy the weapon in earth orbit. When it orbits around the earth to a specified position, it uses the reverse push-down rocket to slow it down, lower its orbit, and shoot at the target according to ground instructions.
Artificial earth satellite orbit
- There are usually three types of orbits (other than low-earth orbit) for orbiting satellites: geosynchronous orbits, solar-synchronous orbits,
- Artificial earth satellite
- The sun-synchronous orbit is an orbital plane that rotates around the Earth's rotation axis in the same direction as the Earth's orbit. The rotational angular velocity is equal to the average angular velocity of the Earth's orbit (360 degrees / year). Its altitude from the earth does not exceed 6000 kilometers. The satellites in this orbit travel the same local time at the same latitude in the same direction. Meteorological satellites and earth resource satellites generally adopt this orbit.
- A polar orbit is an orbit with an inclination of 90 degrees. Each circle of a satellite traveling in this orbit passes over the earth's poles and can overlook the entire earth's surface. Meteorological satellites, earth resources satellites, and reconnaissance satellites often use this orbit.
Orbit
- The characteristic of a forward orbit is that the orbital inclination angle, that is, the angle between the orbital plane and the earth's equatorial plane is less than 90 degrees. Most satellites operating in this orbit are relatively close to the ground and only a few hundred kilometers in height, so they are also called low-earth orbits. China is located in the northern hemisphere. It needs to send satellites into this orbit, and the launch vehicle is launched in the southeast direction. This can use part of the speed of the earth's rotation from west to east, which can save the energy of the rocket. The Earth's rotation speed can be calculated from the equatorial rotation speed, the launch azimuth, and the geographic latitude of the launch point. It is not difficult to imagine that when launching a satellite towards the east on the equator, the available speed is the largest, and the higher the latitude, the lower the available speed.
- Eight scientific and technological test satellites launched by China's Long March 1 and Storm 1 launch vehicles, 17 returnable remote sensing satellites launched by 3 Long March II, 2 C and 2 D launch vehicles, and Long March 2 The Shenzhou test spacecraft launched by the F carrier rocket all used direct orbit. They all took off from Jiuquan Launch Center and were sent into low-Earth orbit. A Beidou navigation test satellite launched by the Long March IIIA carrier rocket also used an orbit.
Artificial Earth Satellite Retrograde Orbit
- A retrograde orbit is characterized by an orbit inclination greater than 90 degrees. To launch a satellite into this orbit, the launch vehicle needs
- Artificial earth satellite
- Since the earth's surface is not ideally spherical, its gravity distribution is also uneven, causing the satellite orbital plane to constantly change in inertial space. Specifically, the Earth's equatorial part is a little bulging, which creates additional attraction to the satellite, and adds a moment to the orbital plane, causing the orbital plane to slowly advance, and the precession direction is related to the orbital inclination. When the orbital inclination is greater than 90 degrees, the moment is counterclockwise, and the orbital plane advances from west to east. Properly adjusting the satellite's orbital height, inclination and shape can make the precession angular velocity of the satellite orbital plane advance 0.9856 degrees every day, which is exactly equal to the daily average angular velocity of the earth's revolution around the sun. This is the circular sun synchronous orbit of great application value. Satellites operating in sun-synchronous orbits can observe satellite clouds and ground targets under the same time and lighting conditions. Meteorological, resource, reconnaissance and other application satellites mostly use this type of orbit. China's 2 Fengyun-1 meteorological satellites launched by the Long March 4 rocket and 2 Earth satellites measuring the atmospheric density, 1 Fengyun-1 meteorological satellite launched by the Long March 4 2 rocket, and a joint resource of China and Brazil These satellites are used by the No. 1 satellite, the China Resources No. 2 satellite, and the No. 5 scientific experimental satellite. They all lifted off from the Taiyuan Launch Center. When the Changsiyi Rocket launched the No. 1 satellite, it also sent a small Brazilian scientific application satellite into solar synchronous orbit by means of one double star.
Equatorial orbit of artificial earth satellite
- Equatorial orbit is characterized by an orbital inclination of 0 degrees and satellites operating above the equator. There are countless such orbits, but one of them is of special importance. Because the satellite's flying speed varies with the height from the ground, the higher the orbit, the lower the speed, and the longer the period of the orbit. Therefore, it can be known from calculations that when it travels from west to east on a circular orbit of 35,786 kilometers high over the equator for one week The time, which is exactly 23 hours, 56 minutes, and 4 seconds, is exactly the same as the time when the earth makes one revolution. This orbit is called the geostationary orbit. Because the satellite's orbit is equal to the Earth's rotation period, and the directions are the same, they remain relatively stationary.
- From the ground, the satellite appears to be fixed at a certain point over the equator. The scientific assumption that global communication can be carried out by uniformly distributing 3 communication satellites in the geostationary orbit has long been a reality. The world's major communications satellites are distributed in this orbit. Some meteorological satellites and early warning satellites were also sent into geostationary orbit. China used the Long March 3 rocket to launch 1 test satellite, 5 Dongfanghong 2 series communication satellites, 2 Fengyun 2 meteorological satellites, and 2 Long March 3A rockets to launch 1 practice 4 detection satellite, 2 2 One Dongfanghong-3 communication satellite and one Zhongxing 22 communication satellite, 10 of these satellites have entered the geostationary orbit predetermined position. To launch this type of satellite, the satellite must carry an apogee engine. After the launch vehicle sends the satellite into the large elliptical synchronous transfer orbit, the ground issues a command to ignite the asteroid apogee engine and move the satellite into a stationary orbit.
Artificial Earth Satellite Polar Orbit
- As far as satellite orbit types are concerned, there is also a polar orbit with an orbital inclination of 90 degrees. It is named after the orbital plane passes through the north and south poles of the earth. Satellites operating in this orbit can fly over any part of the earth. Although China has not developed satellites in such orbits, it has launched satellites in such orbits. The Long March 2C improved rocket took off from Taiyuan 6 times in the form of a double arrow, and sent 12 US iridium stars into space. This is the launch method.
Artificial earth satellite sun-synchronous orbit
- Due to the oblateness of the earth (the earth is not spherical, but bulges at the equator), the satellite orbital plane rotates around the earth's rotation axis. If the rotation direction and angular velocity of the satellite orbital plane around the earth's rotation axis are the same as the direction and average angular velocity of the earth's orbit around the sun, this satellite orbit is called a solar synchronous orbit. Meteorological satellites, resource satellites, and other earth observation satellites use this orbit. The advantage is that not only can the satellite overlook the entire surface of the earth, including the polar regions of the earth, but also the lighting conditions are basic each time the satellite passes through a specific area. Does not change, which is good for obtaining images of high-quality ground targets. [1]
- Some artificial satellites operate in circular orbits, and some operate in elliptical orbits: they also have high and low points: orbits 200 to 2000 km from the ground are called low orbits, orbits between 2000 to 20,000 km from the ground are called middle orbits, and more than 20,000 km from the ground The orbit is called high orbit. In order to complete the scheduled tasks, different satellites have obvious differences in shape and height.
- For example, the use of circular orbits has the advantage of maintaining the same distance from the earth's surface, so satellites used to observe the earth, communications and broadcasting, navigation and positioning and geodetic surveys often use this orbit; however, some satellites use elliptical orbits, such as the Russian "Lightning" communication satellites run in a large elliptical orbit. This is because Russia has a high latitude. If geostationary orbit satellites cannot be used to cover high latitudes, the "lightning" communication satellites have an orbital altitude of 40000km, an apogee of 470km, and an inclination 63 °, the apogee over the northern hemisphere. In this way, the satellite can slowly pass through the territory of Russia, and the time to lose contact with the ground control station is very short. However, in order to ensure uninterrupted communication in Russia, multiple "lightning" satellites are required to cooperate. In addition, if it is for scientific research (study of the intensity of the magnetic field, atmospheric pressure, temperature, density, and intensity distribution of space radiation in different heights of the earth) to make the detection range larger, you can choose a flat orbit. China's practice-1 scientific satellite launched on March 3, 1971, its orbital perigee is 266km and its apogee is l826km. [1]
Classification of artificial earth satellites
Types of artificial earth satellites
- GEO: Geostationary Orbit
- High-orbit satellite, about 36,000 kilometers above the earth's surface, and orbiting the earth on the equator, also known as a synchronous orbit satellite
- Polar Orbit
- Artificial earth satellite
Altitude of artificial satellite
- High-orbit satellite (also known as geostationary satellite): Geostationary Orbit
- High-orbit satellites are about 36,000 kilometers above the earth's surface and orbit the earth on the equator. They are also called geostationary orbiting satellites or geostationary satellites.
- MEO: Medium-Earth Orbit
- LEO: Low-Earth Orbit
Artificial earth satellite weight
- Large satellites (greater than 3000kg)> 3 tons
- Medium-sized satellite (less than 3000kg) <3 tons
- Small satellite (less than 1000kg) <1 ton
- Mini satellite (150kg)
- Micro satellite (50kg)
Artificial Earth Satellite Function
- Commercial communications satellite
- Science satellite
- Military satellite
Classification of artificial earth satellites
- Classified by use:
- Can be divided into broadcasting satellites, communication satellites, meteorological satellites, earth observation satellites, navigation satellites, astronomical satellites, detection satellites, space satellites, tow-free satellites, science and technology satellites, early warning satellites, anti-satellite satellites, etc.
- Broadcast satellite: A satellite designed and manufactured for satellite television.
- Communication satellite: At present, communication satellite is the most closely related artificial satellite. Jufan TV broadcasts, personal mobile phones, high-speed networks and other communications-related services are inseparable from communication satellites.
- Meteorological satellites: In ancient times, people could only speculate on the changing climate based on experience. With the advent of meteorological satellites, people can grasp the climate change within a few days. Meteorological satellites observe the earth from distant space, and not only can observe the weather changes in large areas, but also observe the weather changes in small areas is also his routine task. Generally, when we watch the weather forecast of the news, the satellite cloud picture behind the anchor is the observation result of the meteorological satellite. The typhoon forecast is familiar to everyone. In addition to observing the weather and climate of the earth, meteorological satellites can also monitor the so-called space weather. Such as the storm on the surface of the sun. Such incidents often cause damage to many electrical objects on the planet. Meteorological satellites have other functions as well. It can provide monitoring information for natural disasters such as floods and forest fires, and it can also provide certain information for resources such as fishing grounds or land resources. In this way, the development of various natural resources and natural disaster relief can achieve twice the result with half the effort.
- Earth observation satellites: These satellites allow scientists to gather valuable data about Earth's ecosystems.
- Navigation Satellites: Navigation satellites were originally designed for military use, but later the military decrypted and released this technology due to the enthusiastic demands of the people. One of the most famous and widely used is the Global Satellite Positioning System originally used by the US military, which is referred to as GPS. The use of global satellite systems makes human transportation safer and more efficient. Especially for ships sailing in the vast sea or planes in the vast sky, with the global satellite positioning system, they will not get lost and can control the channel on the most efficient route. Therefore, in addition to increasing safety, shipping costs can be further reduced. At the same time, not only shipping and air transportation, but also other railway transportation can improve transportation efficiency. Due to the development of electronic technology, GPS receivers are getting smaller and smaller. Some advanced car manufacturers have installed this equipment on personal vehicles. Its function can not only be used in the local map, but also can be used to guide the owner to the nearest route through the service station on the ground, and even avoid the trouble of traffic jams. Until today, most global satellite positioning systems have complemented other types of satellites, enabling the aforementioned various satellites to have more accurate positioning capabilities and greatly improving the availability of data.
- Classified by height:
- Artificial earth satellites play an irreplaceable role in all aspects of human production and life. There are many types of artificial earth satellites, their uses are different, and their orbital heights are different. According to their orbital heights, satellites can be divided into: low-orbiting satellites-orbital heights below 5km; medium-orbiting satellites-orbital heights 5 20km; high-orbit satellitesorbit height above 20km. NASA photos of the existing artificial earth satellites in space. The earth is like a honeycomb, surrounded by satellites. Except for geosynchronous orbit satellites, most satellites are close to the surface of the earth. The height of the geostationary satellite from the earth is about 36,000 km, which is about 5.7 earth radii. [2]
Artificial earth satellite flight
- Return satellite
- Non-returning satellite (or transmission satellite)
- Famous satellites (in order of launch time)
- Soviet Sputnik One (October 4, 1957)
- U.S. Sync satellites 1 (1963), 2 (1963) and 3 (1964)
- China Oriental Red One (1970)
- Canadian Brothers 1 (1972)
- Hermes Communications Satellite (1976)
- Keo Satellite-A Space Time Capsule (2006)
Artificial earth satellite service
- satellite telephone
- Satellite internet
- Cable TV
Artificial Earth Satellite Engineering System
- Common systems include structure, temperature control, attitude control, energy, tracking, telemetry, remote control,
- Artificial earth satellite
- 1. Launch site system
- 2. Launch vehicle system
- 3 Satellite system
- 4 control system
- 5. Satellite application system
- 6. Recycling area system (limited to return satellites)
Artificial earth satellite component
- In the satellite system, various equipments are divided into payload and satellite platform according to their functions. The satellite platform is divided into multiple subsystems: payloads (different types of satellites are different, the common ones are :)
- 1. Ground Camera
- 2. Stellar camera
- 3 Onboard payload
- Satellite platforms (provide environmental and technical conditions for payload operations, including :)
- 1. service system
- 2. Thermal Control System
- 3 Attitude and orbit control subsystem
- 4 Program Control Subsystem
- 5. Telemetry system
- 6. Remote control system
- 7. Tracking and testing subsystem
- 8. Power distribution system
- 9. Return Subsystem (limited to returnable satellites)
Gravity problems of artificial earth satellites
- From the perspective of the earth reference system, the magnitude of the gravity of the earth satellites in general changes continuously and does not point to the center of the earth. The satellites do not perform a uniform circular motion. When the satellites run near the ground, the inertial centrifugal force and Coriolis The force of gravity is much smaller than the gravity of the earth. Gravity is approximately equal to the gravity of the earth. The farther the satellite is from the ground, the greater the difference between gravity and the gravity of the earth, which is not the same. Only equatorial orbit satellites make uniform circular orbits around the ground (but the orbiting speed is different from that seen on the geocentric-star system), and the centripetal force is provided by a certain amount of gravity (but not equal to the gravity of the earth) that always points towards the geocentric. The gravity of a geostationary satellite is zero, which is a more special case than when the earth is stationary in the air. [3]
The most artificial satellite in the world
- The successful launch of the first artificial earth satellite in the former Soviet Union opened the prelude to humanity's march to space and greatly stimulated the enthusiasm of countries around the world for developing and launching satellites. The main mission of the first artificial earth satellite launched by the former Soviet Union was not scientific research, but political propaganda. The first satellite to heaven was the most dramatic scientific event in history.
- The first multi-stage rocket launched by the former Soviet Union reached an altitude of more than 900 kilometers, and then flew parallel to the earth at a speed of about 28,800 kilometers per hour. Finally, the satellite broke away from the last stage of the rocket that stopped burning. About 880 kilometers over the sky to establish its own orbit. Satellites orbit the earth every 96.2 minutes. Due to the rotation of the earth, satellites can fly over all continents and all inhabited areas. The United States successfully launched the first "Explorer" -1 satellite on January 31, 1958. The star weighs 8.22 kilograms, has a cylindrical top, 203.2 cm in height, and 15.2 cm in diameter. It follows an elliptical orbit of 360.4 km perigee and 2531 km apogee.
- Sputnik 1 interior
- On November 26, 1965, France successfully launched its first "Satellite Satellite" -1 (Al) satellite. The star weighs about 42 kg and has an operating cycle of 108.61 minutes. It travels in an elliptical orbit at a distance of 526.24 kilometers and an apogee of 1808.85 kilometers with an orbit inclination of 34.24. The launch vehicle for launching the A1 satellite is "Diamond, tA three-stage rocket. It is 18.7 meters long, 1.4 meters in diameter, and has a take-off weight of about 18 tons.
- On February 11, 1970, Japan successfully launched the first man-made satellite "Otaki". The star weighs about 9.4 kilograms, has an orbital inclination of 31.07 ", 339 kilometers at an apogee, and 5138 kilometers at an apogee, and has an operating cycle of 144.2 minutes. The launch vehicle for the launch of the satellite" Okama "is a" Landa "-45 solid-state rocket with a total length of 16.5 Meters, diameter of 0.74 meters, take-off weight of 9.4 tons. The first stage consists of the main engine and two boosters, the thrust is 37 tons and 26 tons respectively; the second stage thrust is 11.8 tons; the third and fourth stage thrusts are 6.5 tons and 1 ton.
- Artificial earth satellite
- On October 28, 1971, the British successfully launched the first artificial satellite "Prosparro". The launch site was at the Woomera rocket launch site in Australia. The launch vehicle was the British Black Arrow launch vehicle. The perigee is 537 kilometers and the perigee is 1593 kilometers. The star weighs 66 kilograms (145 pounds) and its main task is to test new technologies and inventions, such as testing a new telemetry system and solar battery. It also carries a micrometeor probe to measure the density of such high-speed particles of cosmic dust in the upper atmosphere of the earth.
- In addition to the countries mentioned above, Canada, Italy, Australia, Germany, the Netherlands, Spain, India, and Indonesia are also preparing to launch on their own or have commissioned other countries to launch satellites.
- On October 4, 1957, the Soviet Union launched the first artificial earth satellite. This event has epoch-making significance, and it declares that human beings have entered the age of space. The first artificial earth satellite was spherical, 58 cm in diameter, and weighed 83.6 kg. It flies along an elliptical orbit and orbits the earth every 96 minutes. The artificial earth satellite carries a radio transmitter, which continuously sends a "drop-drop-drop" signal to the earth. Some people surround the radio. Listening for the first time from space. Others look up at the sky, trying to search the bright trajectories of artificial Earth satellites at night with the naked eye. However, at that time, few people knew that artificial earth satellites were the precursors of manned spacecraft, and scientists were stepping up preparations for manned space flight.
- A month later, on November 3, 1957, the Soviet Union launched a second artificial earth satellite, which increased its weight by more than 5 times to 508 kg. The satellite was tapered, and in order to save space on the satellite, a sealed bio-cabin was added, and many measuring instruments had to be moved to the last rocket. Lying peacefully in a cylindrical cabin, a puppy named Lykayi. The puppy is connected to medical instruments that measure pulse, breathing, and blood pressure, and these data are reported to the ground at any time by radio. In order to keep the air in the cabin fresh and clean, an air regeneration device and an excretion device for processing feces are also installed. Keep a certain temperature and humidity in the cabin to make the puppy feel comfortable. In addition, there is a self-feeding device that lights up the signal lights three times a day to inform Leica of meals. It is regrettable that due to the limitations of the technical level at the time, the satellite could not be recovered. The test dog lived in the satellite bio capsule for a week. After completing all the experimental tasks, he had to let it poison himself and become the first in space flight A victim.
Artificial Earth Satellite Launching Countries
- As of the end of the 20th century, only a few countries in the world entered the space club-with independent satellite launch capabilities. These countries and regions include (as of February 2007): CIS countries / former Soviet Union, United States, France, Japan, China, United Kingdom, India and Israel. Launches in Iraq and North Korea have not been acknowledged. Brazil made three launch attempts in 1997, 1999 and 2003, but all were unsuccessful. To this day, a few countries still try to enter the space club. Early Italy and Kazakhstan both had the technical conditions for rocket and satellite research and development, and both had rocket launch sites (San Marcoi Offshore Platform and Baikonur Launch Site, mainly for the United States and Russia). Ukraine has rocket manufacturing capabilities but no launch site. The multi-national cooperation ESA, as well as companies such as private maritime launch companies, are also considered members of the space club.
- On October 4, 1957, the world's first artificial earth satellite was made and successfully launched by the Soviet Union. The rocket that carried the satellite gave it the necessary orbital speed of about 8,000 meters per second. According to calculations, the satellite orbits 900 kilometers above the ground; it takes 1 hour and 35 minutes for each full revolution, and the inclination formed between its orbit and the equatorial plane is 65 degrees.
- The satellite is a sphere with a diameter of 58 cm and a weight of 83.6 kg. Built-in two radio transmitters that constantly emit radio signals. Its frequencies are 20.005 and 40.002 MHz (wavelengths are around 15 and 7.5 meters, respectively). The signals are in the form of a telegraph signal, and each signal lasts about 0.3 seconds. The pause time is the same.
- As early as the end of the 19th century, the outstanding Russian scientist Tsiolkovsky had scientifically demonstrated the possibility of using rockets to achieve space flight for the first time.