Artificial satellite: orbiting the earth in space orbitUnmanned spacecraft。The artificial satellite basically moves around the earth according to the laws of celestial mechanics, but the actual movement is very complicated due to the influence of the non spherical gravitational field of the earth, atmospheric resistance, solar gravity, lunar gravity and light pressure on different orbits.The man-made satellite is the spacecraft with the largest number of launches, the widest use and the fastest development.The number of man-made satellites launched accounts for more than 90% of the total number of spacecraft launches.[1]
Artificial satellites can be divided into three categories: scientific satellites, technical test satellites and application satellites.Science satellites are satellites used for scientific exploration and research, mainly including space physics exploration satellites and astronomical satellites, which are used to study the atmosphere, radiation belt, magnetosphere, cosmic rays, solar radiation, etc. of a planet, and can observe other stars. Most man-made satellites in the world areArtificial earth satelliteIn addition, there are artificial Mars satellites.
Satellites are all around in the universeplanetA celestial body in orbit is called a satellite of a planet if it revolves around a planet. For example, the moon revolves around the earth, and it is the satellite of the earth."Artificial satellite" is our "man-made satellite".For scientistsrocketOr othersMeans of deliveryLaunch it into a predetermined orbit to make it go around the earth or other planets forprobeOr scientific research.The earth hasgravitationSoThrowThe object will fall back to the ground, but it will be thrownInitial velocityThe bigger, the object will flyThe farther。NewtonThinkingUniversal gravitationThe law once envisaged that when objects are thrown from a high mountain at different horizontal speeds, the speed will drop faster and the place will be farther away from the foot of the mountain.If there is no air resistance, the object willforeverWill not fall to the ground, it will surround the earthrotateBecome a planet orbiting the earthArtificial earth satellite, or man-made satellite for short.The man-made satellite is the most launched, widely used and fastest growingspacecraft。[2]
After the Soviet Union launched the world's first man-made satellite on October 4, 1957, the United States, France and Japan also launched man-made satellites one after another.China launched its first man-made satellite on April 24, 1970“Dongfanghong No.1”。By the end of 1992, China had successfully launched 33 satellites of different types.[3]
Satellites are generally composed of special systems and support systems.Special system refers to the system directly related to the mission performed by the satellite, also known as payload.The special system of application satellite includes:Communication repeater、Remote sensor、Navigation equipmentEtc;The special systems of scientific satellites are variousSpace physical exploration、Astronomical explorationAnd other instruments;The special system of technology test satellite is the test equipment for various new principles, new technologies, new schemes, new instruments and new materials.Support system refers to the system that ensures the normal operation of satellites and special systems in space, also known as service system, mainly including structural systemPower supply system, thermal control systemattitude controlAnd track control system, radio measurement and control system, etc.For returning satellites, there is also a return landing system.
satellite
The motion orbit of the artificial satellite depends on the mission requirements of the satellite, which can be divided intoLow orbit、Medium high orbit、Geosynchronous orbit、Geostationary orbit、Sun synchronous orbit, largeElliptical orbitandPolar orbit。Artificial satellites fly around the earth at a high speed in low and medium orbits,High orbit satelliteIt can fly around the earth several times to more than ten times a day. It is not limited by territory, airspace and geographical conditions, and has a broad vision.It can quickly exchange information with the ground, including the forwarding of ground information, and can also obtain a large amount of earthRemote sensing informationThe remote sensing area of an earth resources satellite image can reach tens of thousands of square kilometers.staySatellite orbitThe altitude reaches 35786 kilometers, and along the equator of the earthearth rotationWhen flying in the same direction, the rotation period of the satellite around the earth is exactly the same as the rotation period of the earth, and the relative position remains unchanged. This satellite appears to be hanging in high altitude statically on the earth, which is called geostationary orbit satelliteGeostationary satelliteThis kind of satellite can realize the uninterrupted information exchange between the satellite and the ground station, and greatly simplify the equipment of the ground station.The vast majority of TV relay and forwarding communications via satellite are realized by geostationary communication satellites.
The man-made satellite is the spacecraft with the largest number of launches, the widest use and the fastest development.According to the different operating orbits, artificial satellites are divided into low orbit satellites, medium high orbit satellites, various artificial satellites, geosynchronous satellitesGeostationary satellite、Sun synchronous satelliteLarge elliptical orbit satellites and polar orbit satellites;According to the use, artificial satellites can be divided intoCommunication satellite、meteorological satellite、Reconnaissance satellite、navigation satellite、Geodesic satellite、Intercept satelliteEtc.These kinds of man-made satellites with different purposes have made great contributions to mankind.
classification
Announce
edit
By running track
Low orbit satellite, medium orbit satellite, high orbit satelliteGeosynchronous orbit satellite, EarthGeostationary satellite、Sun synchronous orbit satelliteLarge elliptical orbit satellites and polar orbit satellites;It can be divided into scientific satellites, application satellites and technology test satellites according to their uses.[4]
①The geosynchronous orbit is the period of operation andearth rotationA forward trajectory with the same period.But there is a very special orbit calledGeostationary orbitThis orbitaldip angleIt is zero, 35786 kilometers above the earth's equator.From the perspective of people on the ground, the satellites running in this orbit are generally stationaryCommunication satellite，Broadcast satellite，meteorological satelliteThis kind of track is more advantageous.There are countless geosynchronous orbits, but only one geostationary orbit.
②The sun's synchronous orbit is around the earth's rotation axis in the same direction asEarth revolutionThe direction is the same, and the rotation angular speed is equal to the average of the earth's revolutionangular velocity(360 degrees/year), which is no more than 6000 kilometers from the earth.The local time of satellites running in this orbit passing through the same latitude in the same direction is the same.meteorological satelliteEarth resource satellites generally use this orbit.
③ Polar orbit is an orbit with an inclination of 90 degrees. Satellites running in this orbit pass over the earth's poles every circle and can look down on the whole earth's surface.Meteorological satelliteEarth resource satellite、Reconnaissance satelliteThis track is often used.
Satellite engineering
Announce
edit
The general system has structure, temperature control,attitude control, energy, tracking, telemetry, remote control, communication, track control, antenna and other systems,Recoverable satelliteThere is also a recycling system, in addition, there are various special systems set according to the task needs.Satellites can successfully carry out scheduled tasks, which cannot be done by themselves, but need a complete satellite engineering system, which is generally composed of the following systems:
sixRecycling area system (limited to recoverable satellites)
system composition
Announce
edit
In the satellite system, various devices are divided into effective ones according to their different functionsloadandSatellite platformTwo major parts.The satellite platform is divided into several subsystems:[5]
Payloads (different types of satellites are different, and the common ones are:)
1、Ground camera
2、Star camera
3、Payload carried
Satellite platform (provide environment and technical conditions for payload operation, including:)
1、service system
2、Thermal control subsystem
3、Attitude and orbit control subsystem
4、Program control subsystem
5、Telemetry subsystem
6、Remote control subsystem
7、Tracking and testing subsystem
8、Power supply and distribution subsystem
9、Return subsystem (limited to return satellites)
Main purpose
Announce
edit
How to determine the use of artificial satellites
The composition of artificial satellites can basically be divided into two parts: "satellite body" and "payloads".Payroll is the instrument used by satellites to do experiments or services, and the satellite itself is the vehicle to maintain payload operation.The use of a satellite depends on the payload it carries.
What are the types of artificial satellites and what are their uses
The advantage of artificial satellites is that they can process a large amount of data at the same time and transmit them to any corner of the world. The use of three satellites can cover all parts of the world. According to the purpose of use, artificial satellites can be roughly divided into the following categories:
Scientific satellite: launchSpace orbit, satellites for atmospheric physics, astrophysics, geophysics and other experiments or tests such asZhonghua Satellite One, Haber, etc.
Resource satelliteA satellite that takes images of the surface or deep composition and uses them for exploration of the earth's resources.
Interstellar satellite: the satellite that can sail to other planets for exploration and photography is generally calledPlanetary explorationSuch as Pioneer, Mars, Pathfinder, etc.
By track type
Geostationary orbit(GEO: Geostationary Orbit) High orbit satellites are 36000 kilometers high from the earth's surface, and circumnavigate the earth on the equator, also known as geostationary satellites.
Sun synchronous quasi regressive orbit（Synchronous near Recurrent Orbit）
By rail height
High orbit satellite(also known asGeostationary satellite）: Running in geostationary orbit (Geo: Geostationary Orbit).High orbit satellites are about 36000 kilometers high above the earth's surface and orbit the earth on the equator, also known as geostationary satellites orGeostationary satellite。
Medium orbit satellite: MEO: Medium Earth Orbit
LEO satellite(also known asCircumpolar satellite）: LEO: Low Earth Orbit
By satellite weight
Large satellite: more than 3000 kg (3 tons)
Medium satellite: less than 3000kg (3 tons)
Small satellite: less than 1000 kg (1 ton)
Mini satellite: 150kg
Microsatellite: 50kg
Differentiate by use
Scientific satellite
meteorological satelliteIn ancient times, people could only speculate about the changeable climate by experience.The emergence of meteorological satellites has enabled people to grasp the climate change in a few days. Meteorological satellites can observe the Earth from far away space, not only to observe weather changes in large regions, but also to observe weather changes in small regions.Generally, when we watch the weather forecast on the news, the satellite cloud picture behind the anchor is the observation result of the meteorological satellite, and the typhoon forecast is more familiar to everyone.In addition to observing the earth's weather and climate, meteorological satellites can also monitor the so-called space weather, such as storms on the sun's surface.Such events often cause damage to many electrical objects on the earth.The meteorological satellite has other functions. It can provide monitoring information for natural disasters such as floods and forest fires, and can also provide certain information for fishery resources or land resources, so that the development of various natural resources and natural disaster relief can achieve twice the result with half the effort.
Earth observation satelliteThese satellites allow scientists to gather valuable data about the Earth's ecosystem.
Broadcast satellite: Artificial satellite specially designed and manufactured for satellite TV.
Communication satelliteCommunication satellite is the man-made satellite that has the closest relationship with people's life.Communication related services such as TV broadcasting, telephone and network are inseparable from communication satellites.
The light source used to establish the laser link has always beenlaser communicationBecause of the influence of optical transmission media and detectors, the research on laser wavelength is mainly focused on three wavebands of 800nm, 1000nm and 1550nm, excluding the first generation of laser communicationGas laserLater, the laser research used on the satellite mainly focused on thesemiconductor laser 、solid-state laserandFiber laser。
navigation satellite: At the beginning, navigation satellites were designed for military purposes, and then due to the intense demand of the people, the military released the most famous and widely used technology, which was originally used by the US militaryGlobal Positioning System, which is called GPS Global Satellite System for short, makes human traffic safer and more efficient.Especially for ships sailing in the vast sea or aircraft in the vast boundless sky, with GPS, they will not lose their way, and can control the channel on the most efficient route.Therefore, in addition to increasing safety, it can further reduce shipping costs.At the same time, not only shipping and air transportation, but also other railway transportation can improve transportation efficiency.Due to the advanced electronic technology, the GPS receiver is becoming smaller and smaller.Some advanced car manufacturers have installed this set of equipment on personal vehicles.Its function can not only be used as a map, but also lead to the nearest route by the ground service station, or even avoid the trouble of traffic jams.Until today, most of the global positioning systems (GPS) and other kinds of satellites complement each other, making the aforementioned satellites have more accurate positioning capabilities and greatly improving the availability of data.
October 4, 1957.The Soviet Union announced that it had successfully put the world's first man-made satellite orbiting the earth into orbit.American officials claimed that they were shocked not only by the successful launch of the satellite by the Soviet Union, but also by the size of the satellite.This satellite weighs 83 kg, eight times heavier than the satellite that the United States plans to launch at the beginning of the next year. However, the United States does not have the R7 rocket as big as the Soviet Union, so it cannot launch.
The Soviet Union announced that the satellite'ssphereThe diameter is 55cm, it takes 1 hour and 35 minutes to circle the earth, and the maximum height from the ground is 900km. Two channels are used to send signals continuously.Since the orbit and the equator form an angle of 65 degrees, it canMoscowPassing overhead.The Soviet Union did not give a detailed report on the rocket that launched the satellite, but mentioned that it left the ground at a speed of 8 kilometers per second.They said the launch opened the way for interstellar navigation.
This event has epoch-making significance, which declares that mankind has entered the space age.
The first man-made earth satellite was spherical, 58 cm in diameter and 83.6 kg in weight.It travels in an elliptical orbit, circling the earth every 96 minutes.The artificial earth satellite is equipped with aRadio transmitter, constantly sending out "drop drop drop" signals to the earth.Some people surrounded the radio.I listened to the sound from space for the first time.Others looked up at the sky, trying to search the bright track of artificial earth satellite with naked eyes at night.However, few people knew at that time that man-made earth satellites were the pioneers of manned spacecraft, and scientists were stepping up preparations for manned space flight.A month later, on November 3, 1957, the Soviet Union launched the second man-made earth satellite, whose weight increased more than five times, reaching 508 kg.This satellite is conical. In order to save space on the satellite and add a sealed biological capsule, many measuring instruments have to be moved to the last rocket.In the cylindrical cabin lies a dog named "Lekay".The dog is connected with medical instruments to measure pulse, respiration and blood pressure, which can be transmitted by radio at any timeData reportTo the ground.In order to keep the air in the cabin fresh and clean, air regeneration devices and fecal disposal devices are also installed.Keep a certain temperature and humidity in the cabin to make the dog feel comfortable.In addition, there is a self feeding device that lights the signal light three times a day to notify Laika to eat.The Soviet Union officially released an "official" version of Leka's fate: Leka completed a week long flight mission, reaching a height of 1600 km from the earth;According to the plan, it died quietly after eating the last poisonous dinner.However, in 2002, he participated in the former Soviet UnionArtificial earth satelliteDimitri Malashankov, a scientist of the Russian Institute of Biomedical Sciences during the launch, announced a surprising news: Leika did not live as long as the officials of the former Soviet Union claimed. In fact, it died of shock and heat exhaustion just a few hours after flying into the sky.
The test dog became the first victim of space flight in the satellite biological module.
Launch of the first satellite in various countries
Artificial earth satellite
The Soviet Union launched Sputnik-1, the first man-made earth satellite of mankind, on October 4, 1957, which opened the door toSpaceThe prelude to the march has greatly stimulated the enthusiasm of countries all over the world to develop and launch satellites.
The United States successfully launched the first "Explorer" - 1 satellite on January 31, 1958.The star weighs 8.22 kg, has a cylindrical cone top, 203.2 cm high, 15.2 cm in diameterPerigee360.4 kmApogeeThe 2531km elliptical orbit orbits the earth with an inclination of 33.34 "and an operation period of 114.8 minutes.The carrier rocket to launch "Explorer" - 1 is the "Cupid" ℃ four stage carrier rocket.
France successfully launched the first "test satellite" - 1 (A-l) on November 26, 1965.The satellite weighs about 42 kg, has a running period of 108.61 minutes, and runs along an elliptical orbit of 526.24 km perigee and 1808.85 km apogee, with an orbital inclination of 34.24 ".The carrier rocket for launching A1 satellite is "Diamond, tA"Three-stage rocketIt has a total length of 18.7 meters, a diameter of 1.4 meters, and a takeoff weight of about 18 tons.
Japan successfully launched its first man-made satellite, "Otsu", on February 11, 1970.The satellite weighs about 9.4 kg, its orbital inclination is 31.07 ", its perigee is 339 km, its apogee is 5138 km, and its operation period is 144.2 minutes.The carrier rocket for launching "Dayu" satellite is“Randa”-45 Four stage solid rocket,rocketThe total length is 16.5m, the diameter is 0.74m, and the takeoff weight is 9.4t.The first stage consists of the main engine and twoboosterComposition, the thrust is 37 tons and 26 tons respectively;The second stage thrust is 11.8 tons;The third and fourth stage thrust are 6.5 tons and 1 ton respectively.
China successfully launched its first man-made satellite, "Dongfanghong" 1, on April 24, 1970.The star, with a diameter of about 1 meter and a weight of 173 kg, orbits the earth in an elliptical orbit of 439 km perigee and 2384 km apogee, with an orbital inclination of 68.5 "and a period of 114 minutes.The carrier rocket for launching the "Dongfanghong" 1 satellite is the "Long March" 1 three-stage carrier rocket. The rocket is 29.45 meters in length, 2.25 meters in diameter, 81.6 tons in takeoff weight, and 112 tons in launch thrust.
Artificial earth satellite
Britain: Britain successfully launched its first man-made satellite on October 28, 1971“Prospero”The launch site is located at the Woomera rocket launch site in Australia. The carrier rocket is the British Black Arrow carrier rocket.The perigee is 537 kilometers, and the apogee is 1593 kilometers.The satellite weighs 66 kilograms (145 pounds), and its main task is to test various technological innovations, such as a new telemetry system andsolar array。It also carries a micro meteor detector to measure the density of such cosmic dust high-speed particles in the upper atmosphere of the Earth.
India, after years of development, has reached or approached the international advanced level in the R&D and application technology of Indian satellites, and its carrier rocket technology has also made breakthroughs.India has four types of domestic launch vehicles: "Satellite Launch Vehicle 3 (SLV-3)", "Augmented Launch Vehicle (ASLV)", "Polar Satellite Launch Vehicle (PSLV)" and "Geostationary Satellite Launch Vehicle (GSLV)".While vigorously developing rocket and satellite technology, India also seeks to make greater achievements.For example, in 2007, India used one of its first recoverable capsule and three satellitesPolar Satellite Launch VehicleLaunched into space, at 9:20 local time on April 28 (11:50 Beijing time), an Indian PSLV-C9rocketIt was launched with 10 satellites.Following the United States, RussiaEuropean Space AgencyAnd China“One arrow with many stars”Launch technology and“One arrow and ten stars”Be number one.It has obtained important data for the country's future manned space program.In addition, India is also implementing its own moon exploration plan in full swing,Indian Space Research OrganizationIn 2008, India's first lunar probe, Chandrayaan-1, was launched by a polar satellite carrier rocket.
In addition to the above countries, Canada, Italy, Australia, Germany, the Netherlands, Spain and Indonesia are also preparing to launch satellites on their own or have commissioned other countries to launch satellites.
China Satellite
Announce
edit
The first satellite was born
China's first man-made satellite -- Dongfanghong-1
More than 40 years have passed. Today, China has dozens of satellites traveling in space. The Shenzhou experimental spacecraft has returned to the earth. China has begun toManned spaceflightStep.Looking back at China's space history, we cannot but mention that its beginning, "Dongfanghong-1", a high-precision technology, succeeded at one stroke in a period of poor foundation and turbulence.But“Dongfanghong No.1”The birth of satellites has long been a mystery.On April 24, 1970, China successfully launched its first man-made satellite. The perigee altitude of the satellite orbit was 436km, and the apogee altitude was 2384km,Track planeThe included angle with the plane of the earth's equator is 68.5 °, and it takes 114 minutes to circle the earth.The satellite has a mass of 173kg and uses 20.009MHz to play the music of "Dongfanghong".[6]
OriginallyFormer Soviet UnionRespected scientists have deep feelings.Director of the Institute of Geophysics who actively advocated the development of artificial satellitesZhao JiuzhangThe teacher said, "It is impossible to rely on the sky and the earth! The development of aerospace science mainly depends on our own strength."
China's first man-made satellite -- Dongfanghong-1
Although the purpose of investigating satellite development was not achieved in the former Soviet Union, the advanced industry and technology of the Soviet Union still opened the eyes of Chinese scientists.Compared with the situation in the Soviet Union and China, they realized that launching artificial satellites was a big project with complex technology and strong comprehensiveness, which required a high level of science and technology and a strong industrial foundation as the backing.The delegation wrote in the summary that the launchArtificial earth satelliteChina has not yet met the conditions, and should start with rocket sounding according to the actual situation.At the same time, we should base ourselves on China and take the road of self-reliance.
On January 21, 1959, presided over and led the satellite developmentZhang JinfuConveyed to the Academy of SciencesDeng Xiaoping"The satellite will not be released in the next year or the next, which is not commensurate with the national strength"."Satellites still need to be developed, but they need to be delayed".According to the policy of the Central Committee, Zhang Jinfu put forward the idea of "staying under the soup". Due to the national economic difficulties, the satellite development work was suspended and efforts were concentrated on sounding firstrocket。[7]
"651" task
As a result of shortening the battle line, China soon made breakthroughs in the development of sounding rockets.In February 1960, China's experimental liquid sounding rocket was successfully launched for the first time.Since then, various sounding rockets with different uses have been launched in succession, includingMeteorological rocket、Biological rocketEtc.In June 1964, the first medium and short range rocket designed by China was successfully launched;In October, China's first bomb was successfully explodedAtomic bomb。At this time, China has made individual pre research achievements in satellite energy, satellite temperature control, satellite structure, satellite test equipment, etc.At this time, Chinese scientists felt that satellite launch could be put on the agenda.
In December 1964, during the third session of the National People's Congress, Zhao Jiuzhang, who actively advocated China to engage in artificial satellites, wrote to Premier Zhou Enlai and proposed to carry out the development of artificial satellites.At the same time, well-known scientistsQian XuesenIt also submitted a letter to the Central Committee, suggesting accelerating the development of artificial satellites.
Artificial satellite
In May 1965, Premier Zhou Enlai instructed the Academy of Sciences to come up with a specific plan for the first man-made satellite.Responsible for the overall satellite teamQian Ji, led the young scientific and technological workers to quickly come up with a preliminary plan, which can be summarized into three figures and one table: satellite outline drawing, structural layout drawing and satellite operation drawing with red and blue pencilsSubsatellite point trackFigure, main technical parameters and subsystem composition table.
The scheme has been successively obtainedWenjin StreetThe Ministry of the Academy of Sciences and the National Defense Science and Technology Commission Building No. 3 respectively made detailed reports to leaders of the Academy of Sciences such as Zhang Jinfu and leaders of the National Defense Science and Technology Commission such as Luo Shunchu, and Qian Ji and others directly reported to Premier Zhou Enlai.When Premier Zhou learned that Qian Ji's surname was Qian, he said jokingly: "Our chief designer of satellites is also Qian. We are sophisticated. Atoms, missiles and satellites are all inseparable from" money "!
In August 1965, Premier Zhou presided over the meeting of the Central Committee of the Communist Party of China and approved in principle the Proposal on the Work Plan for Developing China's Artificial Satellites issued by the Chinese Academy of Sciences, which identified the development of artificial satellites as the national cutting-edgetechnological development A major task of.It was also determined that the whole satellite project should be organized and coordinated by the National Defense Science and Technology Commission, the satellite body and ground detection system should be in the charge of the Chinese Academy of Sciences, the carrier rocket should be built by the Seventh Aircraft Department, and the satellite launch site should be built by the National Defense Science and Technology Commission test base.Since the proposal was formally put forward in January, the country named the code of the artificial earth satellite project "651" mission.People, wealth and goods across the country all turn on the green light when encountering "651"China SatelliteFrom the comprehensive planning stage to the engineering development stage.
On April 24, 1970, the "Long March" 1 carrier rocket successfully sent China's first man-made satellite "Dongfanghong" 1 into space. It is worth mentioning that "Dongfanghong" 1 is heavier thanSu Mei。
From October 20 to November 30, 1965, entrusted by the National Defense Science and Technology Commission, the Academy of Sciences held a demonstration meeting on the overall plan of China's first man-made satellite in Beijing, which lasted 42 days.At the meeting, Qian Ji reported the overall plan of China's first man-made satellite.More than 120 military and civilian experts, including those from the sea, land and air fields, repeatedly demonstrated the purpose and task of launching artificial satellites.
At the conference, code named "651", it was determined that China's first man-made satellite was an experimental satellite for scientific exploration, whose mission was to obtain basic experience and design data for the development of China's earth observation, communication broadcasting, meteorology and other application satellites;The launch was scheduled for 1970;The symbol of success is "being able to go up, catch attention, hear and see."
One of the more confidential topics in the meeting was how to determine the weight of China's first satellite.This issue concerns the level of missile weapons.Because the early launch vehicles of satellites were all developed on the basis of missiles, launching satellites is essentially to show a country's military strength.Although China's satellite project started late, experts believe that China's starting point should be high, and the first satellite should be more advanced in weight and technology than the first satellite of the United States and the Soviet Union.The first satellite of the Soviet Union weighs 83.6 kg, while the first satellite of the United States weighs only 8.2 kg.The meeting finally determined that China's first satellite was about 100 kg (in fact, it was 173 kg when it was finally launched).
"Dongfanghong"
People who marched on the streets 30 years ago may have forgotten the celebration scene at that time, but the "Oriental Red" melodious music emitted by satellites from space has long remained in people's memory.The naming of "Dongfanghong No.1" and the birth of music cannot be ignoredChina's space industryHe Zhenghua, an unknown paver in China.
The calling signal of the first Soviet satellite was Diddida telegraph code, and the telemetry signal was intermittent.What should China's satellite signals be like?He Zhenghua, the leader of the Satellite General Team, believed that China should surpass the Soviet Union and send a continuous signal with Chinese characteristics and recognized globally.at that timeCentral People's Broadcasting StationThe external call sign is the music of "Dongfanghong", and in a sense, "Dongfanghong" has also become the symbol of "Red China".For the sake ofMao ZedongHe Zhenghua also proposed that the satellite be named "Dongfanghong-1".These proposals were endorsed by experts at the "651" meeting.In May 1966, after the leadership of the Commission of Science, Technology and Industry for National Defense, the Chinese Academy of Sciences, and the Department of Seventh Machinery IndustryLuo ShunchuZhang JinfuPei LishengQian Xuesen and others jointly agreed to name China's first man-made satellite "Dongfanghong-1".In early 1967, it was officially determined that China's first man-made satellite would broadcast the music of "Dongfanghong", so that people all over the world could hear the voice of Chinese satellites.
Because at that time“the Great Proletarian Cultural Revolution”During the unrest, broadcasting "Dongfanghong" music is not only a scientific research task, but also a political task with great responsibility.If the satellite changes its tone or does not make a sound after being put on board, it is undoubtedly a major political issue according to the saying of "putting the satellite on the line", and the developers may be sent to the 18th hell.Under the heavy ideological burden and mental pressure, He Zhenghua and Liu Chengxi, the main designer of the musical device, risked political risks and began their technical exploration, solving a series of problems such as musical confusion and tone sandhi.The "Dongfanghong" music is finally played by electronic music, and the circuit is used to simulate the sound of aluminum plate zither.The first batch of authentic products of the music device was produced in a factory in Chongqing in the first half of 1968. Because the production order was extremely abnormal at that time, many components in the product had faulty soldering.The final product was re produced by Shanghai Scientific Instrument Factory.
"Red Storm"
The whole development of China's first man-made satellite project was mostly carried out during the most turbulent years of the "Cultural Revolution".At that time, the "Red Storm" that swept the country hit every unit undertaking satellite engineering tasks.At the beginning of 1967, the Chinese Academy of Sciences, the Ministry of Seventh Aircraft Engineering and its subordinate units were seized by "mass organizations", and the original leaders of the Satellite Design Institute were "sidelined". Many scientists were identified as“reactionary academic authority”"Spy" and "ghosts and snakes" were criticized.Even ordinary scientific and technological personnel, many relatives and social relations were impacted and affected in the movement.The development of satellites conflicts with the "revolution".
The "revolution" at that time required everyone to hold a "treasure book" in hand, recite quotations, and offer loyalty sincerely.Satellite development can only be done after participating in the "revolution", otherwise it will be labeled as "not highlighting politics".When scientists are criticized, the backbone of science and technology business should also participate in the "fight".Due to the continuous fighting, the traffic is blocked, and the supply of equipment is not available, the satellite development industry is in danger of premature death.
Under such circumstances, in early 1967, Premier Zhou Enlai andCommunist military leaderThe Vice Premier took a series of measures and announced that:China Academy of Space TechnologyQian Xuesen was appointed as the president, and was included in the military order. He did not carry out the "four major" of the "cultural revolution" (that is, big voice, big release, big character newspaper, big debate).The Institute of Space Technology has selected elite generals from many units to centralize the research forces scattered in various departments, exercise unified leadership, make scientific research and production go on as usual, and ensure the timely launch of China's first satellite.
At the beginning of the establishment of the Institute of Space Technology, the material conditions needed for developing satellites were very scarce, such as few test equipment, incomplete test equipment, and insufficient processing equipment.The satellite manufacturing factory is transformed from a scientific instrument factory, and faces many difficulties in personnel, technology, equipment and management.Riveting is an indispensable process in satellite manufacturing.But at that time, the satellite factory had not been dry, and there was no riveter and no truss to fix the workpiece in the first sample and test stage of the satellite. The workers used a small hammer as the truss to knock the rivets up one by one.Under such conditions, the satellite factory has solved the problems of riveting and anodizingElectropolishingLarge area gold plating of bright aluminum parts, heat treatment of aluminum parts and other process problems.
In order to verify the correctness and rationality of the design, the "Dongfanghong I" satellite has to carry out various operations on the ground, including components, materials, stand-alone subsystems and the entire satelliteEnvironmental simulation test。The launch site is scheduled to launch the satellite at a cold time, and the satellite factory has no test site that meets the requirements. The test of "thermal control sample satellite" was conducted in a cold storage of the Naval Logistics Department in the summer of 1968.Many of the difficulties are solved by scientific and technological personnel who take advantage of the simple conditions, adopt local methods and pool their wisdom.The day after the satellite was launched, many international friends came to visit the satellite at the Institute of Space Technology. The environmental conditions at that time made the visitors sigh: "Dongfanghong-1" was a miracle!
Unforgettable 4 · 24
On April 1, 1970, it was loaded with two "Dongfanghong-1" satellites and one“Long March One”Special train for launch vehicle arrives in northwest ChinaJiuquan Satellite Launch Center。
Northwest in AprilGobiOn the day, you should also wear cotton padded clothes. At night, you can feel cold even wrapped in a fur coat.More than 30 meters above the groundLongmen TowerOn the working platform, scientific and technical personnel eliminate all faults and test again and again, day and night.
At 3:50 on April 24, 1970, Premier Zhou Enlai telephoned Luo Shunchu, Deputy Director of the National Defense Science and Technology Commission, to inform him that Chairman Mao Zedong had approved the launch. I hope everyone will work hard and carefully to win glory for the motherland.
At 21:35, the time for satellite launch finally arrived."Dongfanghong-1" left the launch pad with the "Long March 1" carrier rocket in the roar of the engine.At 21:48, the satellite separated from the rocket and entered orbit.At 21:50, the State Broadcasting Administration reported that the "Dongfanghong" music broadcast by China's first satellite was clear and loud.
At 18:00 on April 25, 1970, Xinhua News Agency authorized the world to announce that on April 24, 1970, China successfully launched its first man-made satellite. The perigee height of the satellite's orbit was 439 kilometers, the apogee height was 2384 kilometers, and the angle between the orbital plane and the Earth's equatorial plane was 68.5 degrees. It circled the Earth for 114 minutes.The satellite weighs 173kg and broadcasts the music of "Dongfanghong" at a frequency of 20.009 megacycles.
However, Mr. Zhao Jiuzhang, who devoted all his efforts to China's first man-made satellite, could not wait for this moment.He was wrongfully framed and persecuted for no reason and died a year and a half ago.Many scientists heard the music of "Dongfanghong" in the cowshed.
After the launch of the "Dongfanghong I" satellite, the actual working time of various instruments on the satellite far exceeded the design requirementstransmitterAfter 28 days of continuous work, a large number of engineering telemetry parameters were obtained, which provided valuable basis and experience for the subsequent satellite design and development.
The successful launch of "Dongfanghong-1" has laid a very solid foundation for the development of China's aerospace technology, and has driven ChinaAerospace industryThe rise of China's space technology has kept pace with the world's space technology frontier, marking China's entry into theera of space-flight。
Some artificial satellites
Chang'e-1
China has launched three generations of communication satellites.The first generation communication satellites were two communication satellites launched in 1984 and one on February 1, 1986Dongfanghong No.2Practical communication and broadcasting satellite.The second generation communication satellite was launched on March 7, 1988, December 22, 1988, February 4, 1990 and November 28, 1991 with four C-band satellitesTransponderOfDongfanghong No.2 ACommunication satellite.The third generation communication satellite was launched on May 12, 1997Dongfanghong No.3Geostationary communication satellite.
From April 24, 1970, when China successfully launched its first satellite to October 2005, China has successfully launched nearly 100 domestic satellites, 6 spaceships and 27 foreign satellites.
moonscape
China's first communication satellite was launched on January 29, 1984, with partial success.This is an experimental communication satellite.
The first geostationary orbit test communication satellite, Dongfanghong II, was successfully launched on April 8, 1984, making China the fifth country in the world to launch geostationary orbit communication satellites on its own.
The practical radio and communication satellite Dongfanghong-2A was successfully launched on March 7, 1988.The satellite has greatly improved China's communication, radio and television transmission conditions.
The medium capacity radio communication satellite Dongfanghong 3 was successfully launched on May 12, 1997.The satellite has improved China's international communications and communications in remote mountainous areas in the west.
Wind and cloudMeteorological satellite seriesIncluding FY-1 solar synchronous orbit meteorological satellite andFengyun IIThere are two categories of geostationary meteorological satellites.Fengyun 1 and Fengyun 2 have launched four and three times respectively in Chinaweather forecastAnd meteorological research.
On September 7, 1988, China's first meteorological satellite Fengyun 1 was launched by the Long March 4 rocket.
China launched its first geostationary meteorological satellite, Fengyun 2A, on June 10, 1997, and officially delivered it to users on December 1, 1997.On June 25, 2000, Fengyun 2B was launched.Another one was launched on October 19, 2004FY-2 meteorological satellite。
The space physics exploration satellites that China has launched are mainly the "Shijian" satellite series.It was successfully launched on March 3, 1971Shijian 1 satellite。On September 20, 1981, a three-star rocket successfully launched Shijian No.2, Shijian No.2 A and Shijian No.2 B.It was successfully launched on February 8, 1994Shijian IV satellite。
A total of eight satellites were launched: Shijian No.1, launched in March 1971;Shijian No.2, Shijian No.2 A and Shijian No.2 B launched with a three-star rocket on September 20, 1981;Shijian IV, launched on February 8, 1994;Shijian V, launched on May 10, 1999.The Shijian VI A and B satellites were launched on September 9, 2004.
Shijian 1 satellite isDongfanghong-1 satelliteOn the basis ofSolar power supply system8 space technology test and detection projects.On March 3, 1971, Shijian 1 satellite was built byLong March 1 RocketSuccessfully launched.The satellite has operated in orbit for more than 8 years and sent back a large amount of scientific detection and test data to the ground.
Shijian 2 satellite is specially used for space physics explorationScience Experiment Satellite。The satellite weighs 250 kg, and the main body of the satellite is an octahedral prism with a diameter of 1.23 meters and a height of 1.1 meters.On September 20, 1981, China launched a three-star rocket, and Shijian No.2 was one of them.
On April 24, 1970, China successfully launched its first satellite, Dongfanghong-1.The satellite weighs 173kg and is equipped with an "Dongfanghong" electronic music generator and scienceDetecting instrumentEquipment.Its mission is to detect the space ionosphere andEarth's atmosphereDensity, and send relevant data back to the ground.Therefore, Dongfanghong-1 is aSpace explorationThe nature of the technology test satellite.
From October 1999 to October 2003, China launched three earth resource satellites.
From April 24, 1970 to October 31, 2000, China launched 74 spacecraft, covering four orbits possessed by the Earth.Among them, there is one domestic experimental spaceship, 47 domestic satellites and 26 foreign satellites.Currently, there are mainly 47 domestic satellites,
Running track
Announce
edit
Forward track
The feature of the forward orbit is that the inclination of the orbit, that is, the included angle between the orbit plane and the equatorial plane of the earth, is less than 90 degrees.The vast majority of satellites operating in this kind of orbit are close to the ground, and their altitude is only hundreds of kilometers, so they are also called low Earth orbit.China is located in the northern hemisphere, so it is necessary to send satellites into this orbit, and launch the carrier rocket in the southeast direction, so that part of the speed of the earth's rotation from west to east can be used, thus saving the energy of the rocket.Earth rotation speedIt can pass the equator rotation speed, launch azimuth and launch pointGeographic latitudeCalculated.It is not hard to imagine that the speed available for launching satellites due east from the equator is the highest, and the higher the latitude, the lower the speed.
Long March 1Storm One8 science and technology test satellites launched by two kinds of launch vehicles, and 17 recoverable satellites launched by three kinds of launch vehicles: Long March II, II C, II DRemote sensing satelliteAnd usingLong March 2F carrier rocketThe Shenzhou experimental spacecraft launched are all in forward orbit.They all took off from Jiuquan Launch Center and were sent into low Earth orbit.adoptLong March 3A carrier rocket1 launchedBeidou NavigationThe test satellite also adopts forward orbit.
Retrograde orbit
Retrograde orbitThe feature of is that the inclination of the track is greater than 90 degrees.To put the satellite into this orbit, the carrier rocket needs to be launched in the southwest direction.Not only can't use part of the earth's rotation speed, but also pay extra energy to overcome the earth's rotation.Therefore, except for the sun synchronous orbit, this kind of orbit is generally not used.
Artificial satellite
Because the earth's surface is not an ideal sphere and its gravity distribution is uneven, the satellite's orbital plane isInertial spaceIs constantly changing.To be specific, the equator of the earth is somewhat swollen, which creates additional attraction for the satellite, and adds a torque to the orbital plane to make the orbital plane slowly precession. The precession direction is related to the orbital inclination.When the inclination of the track is greater than 90 degrees, the moment is counterclockwise, and the track plane precesses from west to east.Properly adjust the satellite'sTrack height, inclination and shape, which can make the precession angular velocity of the satellite orbital plane move 0.9856 degrees eastward every day, just equal toThe earth revolves around the sunThis is the circular sun synchronous orbit with great application value.
Satellites operating in sun synchronous orbit can observe satellite clouds and ground targets under the same time and light conditions.Meteorological, resource, reconnaissance and other application satellites mostly use this kind of orbit.Two Chinese rockets launched by Long March 4FY-1 meteorological satelliteAnd 2 measurementsAtmospheric densityThis orbit is used by the Earth satellites of China, 1 Fengyun 1 meteorological satellite launched by Long March 4-2 rocket, 1 Ziyuan 1 satellite jointly made by China and Brazil, 1 China Ziyuan 2 satellite, and 1 Shijian 5 scientific test satellite.They were all launched from the Taiyuan launch center.When the Long 4B rocket launched the ZY-1 satellite, it also sent a small Brazilian scientific application satellite into the sun synchronous orbit by means of one rocket and two satellites.
Equatorial orbit
Equatorial orbitIt is characterized by an orbit inclination of 0 degrees and satellites operating over the equator.There are countless such orbits, but one of them, the geostationary orbit, is of special importance.Due to the satelliteFlight speedIt varies with the height from the ground. The higher the orbit is, the smaller the speed is, and the longer the circle period is. Therefore, according to the calculation, when it travels from west to east for one week on a circular orbit 35786 kilometers above the equator, it is exactly 23 hours, 56 minutes, and 4 seconds, which is the same as the time when the earth rotates for one week, this orbit is called the geostationary orbit.Because the orbit period of the satellite is equal to the rotation period of the earth, and the directions of the two are the same, they remain relatively stationary.Seen from the ground, the satellite seems to be fixed at a certain point above the equator.The scientific assumption that global communication can be achieved by evenly distributing three communication satellites in geostationary orbit has long become a reality.The world's major communication satellites are distributed in this orbit.Some meteorological satellites and early warning satellites have also been sent into geostationary orbit.China has successively launched one test satellite, five Dongfanghong 2 series communication satellites, two Fengyun 2 meteorological satellites, one Shijian 4 exploration satellite and two others with Long March 3A rocketDongfanghong 3 communication satellite1 Zhongxing 22 communication satellite, and 10 of these satellites have entered into the geostationary orbit.When launching this kind of satellite, it is necessary to carryApogee engineAfter the launch vehicle sends the satellite into the large ellipse synchronous transfer orbit, the ground will send a command to ignite the apogee engine on the satellite and move the satellite into the geostationary orbit.
Polar orbit
In terms of satellite orbit type, there is also a polar orbit with an orbit inclination of 90 degrees.It gets its name because 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 operating in such orbits, it has launched satellites in such orbits.Long March II CThe improved rocket took off from Taiyuan for six times in the form of one arrow and two stars, bringing 12 USIr satelliteSending into space belongs to this launch mode.
September 20, 1981, for use in ChinaStorm 1 carrier rocketThe successful launch of three satellites (Shijian II, Shijian IIA and Shijian IIB) is an important achievement of China in space exploration and new technology testing, making China the third master in the worldOne arrow with many starsCountries that launch technology.
Satellite camera
Announce
edit
The first 12 large-scale high-precision satellite tracking cameras designed by Baker and Nunn in the 1950s were set in the ± 35 ° latitude belt around the earth.This camera is specially designed with a focal length of 50 cm and a diameter of 50 cmSchmidtOptical system (seeSchmidt telescope）The corrector is composed of three lenses with a field of view of 5 °× 30 °.The focal plane is an approximate spherical surface with a radius of 50 cm.The long photosensitive film with a width of about 56 mm shall be applied to the film after being deformed by 6-7 kg pulling forcesupportingOn the board.The rack is a three-axis device, which uses a large arc to approach the arc segment of ± 30 ° near the highest point of the satellite's apparent trajectory for tracking. The angular velocity can be continuously adjusted between 0 and 7000 per second.For a satellite with an angular velocity of 1 ° per second, when the tracking error is ± 1%, a dark satellite with a magnitude of 11 can be photographed.When the camera works in a fixed way, it can take 6 satellites.It has a cylindrical fracture shutter, which rotates around the focal plane with high precisionfixed starOr the star drag mark of the satellite cuts out the fracture used as the measurement mark. Two fractures are cut out every revolution, and the other "clamshell" shaped master shutter is concentrically closed outside the fracture shutter.Each time the clam shell is opened and closed, an exposure is completed. During this period, the star drag marks are cut five fractures by the fracture shutter.There are five kinds of exposure time: 0.2, 0.4, 0.8, 1.6 and 3.2 seconds.At the central moment of forming the third fracture, the dial of slave clock (minute, second, 0.01 second dial) and 100PerimeterscanningcrtThe timing highlight of is projected to the end of the substrate.The timing accuracy is 1 millisecond, and the position accuracy is 2.When the camera takes a fixed shot of a low-speed satellite, the star image is obviously prolonged due to the long exposure time, which reduces the measurement accuracy.The improved design of the Beck Nunn camera is to tilt the original vertical axis to the polar axis, and the camera revolves around the polar axis at a constant speed, making the star become a point image.
Cosmic velocity
Announce
edit
The first cosmic speed is also called the orbit speed: v1=7.9Km/s, which is the satellite's orbit around the earthUniform circular motionThe maximum speed is also the minimum speed for launching satellites on the earth's surface.
The second cosmic speed is also called breakaway speed: V2=11.2km/s, which is the minimum launch speed at which a satellite can break away from the constraints of the earth's gravity and no longer move around the earth.
The third cosmic speed is also called escape speed: v3=16.7Km/S, which refers to the minimum launch speed at which a satellite can fly out of the sun and into space outside the solar system
Mercury dual imaging system
Announce
edit
In April 2015, NASA released images taken by the Visible Light and Infrared Spectrometer (VIRS) carried by the Messenger spacecraft, showing some scenes on the surface of Mercury that may be volcanic pipes or fresh impact craters.In order to highlight the geological characteristics, these images were superimposed with the black and white images taken by the Mercury Dual Imaging System (MDIS) on the Messenger probe.
NASA's Messenger Mercury probe crashed into the surface of Mercury.The specific time of impact will be 3:30 a.m. on May 1, 2015.However, when the impact occurs, the Messenger spacecraft will be located behind Mercury, so it cannot be observed from Earth.In the image sent back by the Messenger spacecraft, a cliff with a height of 2 kilometers can be seen, which cuts through a crater called "Duccio".This is a compressive fault formed in the early cooling and contraction process of Mercury, which is the reflection of the strong internal stress on the surface.
