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How many artificial satellites fly above the earth? The world of satellites: what, where and whose in low-Earth orbit.

Just as seats in a theater provide different perspectives on a performance, different satellite orbits provide perspectives, each with a different purpose. Some appear to hover above a point on the surface, providing a constant view of one side of the Earth, while others circle our planet, passing over many places in a day.

Types of orbits

At what altitude do satellites fly? There are 3 types of near-Earth orbits: high, medium and low. At the highest level, farthest from the surface, as a rule, many weather and some communications satellites are located. Satellites rotating in medium-Earth orbit include navigation and special ones designed to monitor a specific region. Most scientific spacecraft, including NASA's Earth Observing System fleet, are in low orbit.

The speed of their movement depends on the altitude at which satellites fly. As you approach the Earth, gravity becomes stronger and the movement accelerates. For example, NASA's Aqua satellite takes about 99 minutes to orbit our planet at an altitude of about 705 km, while a meteorological device located 35,786 km from the surface takes 23 hours, 56 minutes and 4 seconds. At a distance of 384,403 km from the center of the Earth, the Moon completes one revolution in 28 days.

Aerodynamic paradox

Changing the satellite's altitude also changes its orbital speed. There is a paradox here. If a satellite operator wants to increase its speed, he can't just fire up the engines to speed it up. This will increase the orbit (and altitude), resulting in a decrease in speed. Instead, the engines should be fired in the opposite direction of the satellite's motion, an action that would slow down a moving vehicle on Earth. This action will move it lower, allowing for increased speed.

Orbit characteristics

In addition to altitude, a satellite's path is characterized by eccentricity and inclination. The first relates to the shape of the orbit. A satellite with low eccentricity moves along a trajectory close to circular. An eccentric orbit has the shape of an ellipse. The distance from the spacecraft to the Earth depends on its position.

Inclination is the angle of the orbit relative to the equator. A satellite that orbits directly above the equator has zero inclination. If spacecraft passes over the northern and south poles(geographical, not magnetic), its inclination is 90°.

All together - height, eccentricity and inclination - determine the movement of the satellite and how the Earth will look from its point of view.

High near-Earth

When the satellite reaches exactly 42,164 km from the center of the Earth (about 36 thousand km from the surface), it enters a zone where its orbit matches the rotation of our planet. Since the craft is moving at the same speed as the Earth, i.e., its orbital period is 24 hours, it appears to remain stationary over a single longitude, although it may drift from north to south. This special high orbit is called geosynchronous.

The satellite moves in a circular orbit directly above the equator (eccentricity and inclination are zero) and remains stationary relative to the Earth. It is always located above the same point on its surface.

The Molniya orbit (inclination 63.4°) is used for observation at high latitudes. Geostationary satellites are tied to the equator, so they are not suitable for far northern or southern regions. This orbit is quite eccentric: the spacecraft moves in an elongated ellipse with the Earth located close to one edge. Because the satellite is accelerated by gravity, it moves very quickly when it is close to our planet. As it moves away, its speed slows down, so it spends more time at the top of its orbit at the edge farthest from Earth, the distance to which can reach 40 thousand km. The orbital period is 12 hours, but the satellite spends about two-thirds of this time over one hemisphere. Like a semi-synchronous orbit, the satellite follows the same path every 24 hours. It is used for communication in the far north or south.

Low near-Earth

Most scientific satellites, many meteorological and space station are in a nearly circular low-Earth orbit. Their tilt depends on what they are monitoring. TRMM was launched to monitor rainfall in the tropics, so it has a relatively low inclination (35°), remaining close to the equator.

Many of NASA's observing system satellites have a near-polar, high-inclination orbit. The spacecraft moves around the Earth from pole to pole with a period of 99 minutes. Half of the time it passes over the day side of our planet, and at the pole it turns to the night side.

As the satellite moves, the Earth rotates underneath it. By the time the vehicle moves to the illuminated area, it is over the area adjacent to the zone of its last orbit. In a 24-hour period, the polar satellites cover most of the Earth twice: once during the day and once at night.

Sun-synchronous orbit

Just as geosynchronous satellites must be located above the equator, which allows them to remain above one point, polar orbiting satellites have the ability to remain at the same time. Their orbit is sun-synchronous - when the spacecraft crosses the equator, local solar time is always the same. For example, the Terra satellite always crosses it over Brazil at 10:30 am. The next crossing 99 minutes later over Ecuador or Colombia also occurs at 10:30 local time.

A sun-synchronous orbit is essential for science because it allows sunlight to the Earth's surface, although it will vary depending on the season. This consistency means scientists can compare images of our planet from the same season over several years without worrying about too big jumps in light, which could create the illusion of change. Without a sun-synchronous orbit, it would be difficult to track them over time and collect the information needed to study climate change.

The companion's path here is very limited. If it is at an altitude of 100 km, the orbit should have an inclination of 96°. Any deviation will be unacceptable. Because atmospheric resistance and the gravitational force of the Sun and Moon change the spacecraft's orbit, it must be adjusted regularly.

Injection into orbit: launch

Launching a satellite requires energy, the amount of which depends on the location of the launch site, the height and inclination of the future trajectory of its movement. Getting to a distant orbit requires more energy. Satellites with a significant inclination (for example, polar ones) are more energy-intensive than those circling the equator. Insertion into a low-inclination orbit is aided by the rotation of the Earth. moves at an angle of 51.6397°. This is necessary to make it easier for space shuttles and Russian rockets to reach it. The height of the ISS is 337-430 km. Polar satellites, on the other hand, do not receive any assistance from the Earth's momentum, so they require more energy to rise the same distance.

Adjustment

Once a satellite is launched, efforts must be made to keep it in a certain orbit. Because the Earth is not a perfect sphere, its gravity is stronger in some places. This unevenness, along with the gravitational pull of the Sun, Moon and Jupiter (the most massive planet solar system), changes the inclination of the orbit. Throughout their lifetime, the GOES satellites have been adjusted three or four times. NASA's low-orbiting vehicles must adjust their inclination annually.

In addition, near-Earth satellites are affected by the atmosphere. The uppermost layers, although quite rarefied, exert a strong enough resistance to pull them closer to the Earth. The action of gravity leads to the acceleration of satellites. Over time, they burn up, spiraling lower and faster into the atmosphere, or fall to Earth.

Atmospheric drag is stronger when the Sun is active. Just like the air in hot air balloon expands and rises when heated, the atmosphere rises and expands when the Sun gives it additional energy. Thin layers of the atmosphere rise, and denser layers take their place. Therefore, satellites orbiting the Earth must change their position approximately four times a year to compensate for atmospheric drag. When solar activity is at its maximum, the position of the device has to be adjusted every 2-3 weeks.

Space debris

The third reason forcing a change in orbit is space debris. One of Iridium's communications satellites collided with a non-functioning Russian spacecraft. They crashed, creating a cloud of debris consisting of more than 2,500 pieces. Each element was added to the database, which today includes over 18,000 objects of man-made origin.

NASA carefully monitors everything that may be in the path of satellites, since orbits have already had to be changed several times due to space debris.

Engineers monitor the position of space debris and satellites that could interfere with the movement and carefully plan evasive maneuvers as necessary. The same team plans and executes maneuvers to adjust the satellite's tilt and altitude.

An Earth satellite is any object that moves along a curved path around a planet. The moon is original natural satellite Earth, and there are many artificial satellites, usually in close orbit to Earth. The path followed by a satellite is an orbit, which sometimes takes the shape of a circle.

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To understand why satellites move the way they do, we have to go back to our friend Newton. Newton proposed that a gravitational force exists between any two objects in the Universe. If not for this force, a satellite moving near the planet would continue to move at the same speed and in the same direction - in a straight line. However, this rectilinear inertial path of the satellite is balanced by a strong gravitational attraction directed towards the center of the planet.

Orbits of artificial earth satellites

Sometimes the orbit of an artificial Earth satellite looks like an ellipse, a squashed circle that moves around two points known as foci. The same basic laws of motion apply, except that the planet is at one of the foci. As a result, the net force applied to the satellite is not uniform throughout the orbit, and the satellite's speed is constantly changing. It moves fastest when it is closest to Earth - a point known as perigee - and slowest when it is furthest from Earth - a point known as apogee.

There are many different satellite orbits of the Earth. The ones that receive the most attention are geostationary orbits because they are stationary over a specific point on the Earth.

The orbit chosen for an artificial satellite depends on its application. For example, live broadcast television uses geostationary orbit. Many communications satellites also use geostationary orbit. Other satellite systems, such as satellite phones, may use low-Earth orbits.

Likewise, satellite systems used for navigation, such as Navstar or Global Positioning (GPS), occupy a relatively low Earth orbit. There are also many other types of satellites. From weather satellites to research satellites. Each will have its own orbit type depending on its application.

The actual Earth satellite orbit chosen will depend on factors including its function, and the area in which it is to serve. In some cases, the Earth satellite's orbit can be as large as 100 miles (160 km) for a LEO low earth orbit, while others can reach over 22,000 miles (36,000 km) as in the case of a GEO low earth orbit.

The first artificial earth satellite

The first artificial earth satellite was launched on October 4, 1957 Soviet Union and was the first artificial satellite in history.

Sputnik 1 was the first of several satellites launched by the Soviet Union in the Sputnik program, most of which were successful. Satellite 2 followed the second satellite in orbit and also the first to carry an animal on board, a female dog named Laika. Sputnik 3 suffered the first failure.

The first earth satellite had an approximate mass of 83 kg, had two radio transmitters (20.007 and 40.002 MHz) and orbited the Earth at a distance of 938 km from its apogee and 214 km at its perigee. Analysis of radio signals was used to obtain information about the concentration of electrons in the ionosphere. Temperature and pressure were encoded over the duration of the radio signals it emitted, indicating that the satellite was not perforated by a meteorite.

The first earth satellite was an aluminum sphere with a diameter of 58 cm, having four long and thin antennas ranging from 2.4 to 2.9 m in length. The antennas looked like long mustaches. The spacecraft received information about the density of the upper atmosphere and the propagation of radio waves in the ionosphere. Instruments and sources of electrical energy were housed in a capsule that also included radio transmitters operating at 20.007 and 40.002 MHz (about 15 and 7.5 m wavelength), emissions were made in alternate groups of 0.3 s duration. Ground telemetry included temperature data inside and on the surface of the sphere.

Because the sphere was filled with pressurized nitrogen, Sputnik 1 had its first opportunity to detect meteorites, although it did not. The loss of internal pressure due to penetration to the external surface was reflected in the temperature data.

Types of artificial satellites

There are artificial satellites different types, shapes, sizes and play different roles.

Weather satellites help meteorologists predict the weather or see what's happening in at the moment. A good example is the Geostationary Operational Environmental Satellite (GOES). These earth satellites typically contain cameras that can return photographs of Earth's weather, either from fixed geostationary positions or from polar orbits.
Communications satellites allow the transmission of telephone and information conversations via satellite. Typical communications satellites include Telstar and Intelsat. Most important feature A communications satellite is a transponder—a radio receiver that picks up a conversation on one frequency, then amplifies it and retransmits it back to Earth on a different frequency. A satellite typically contains hundreds or thousands of transponders. Communication satellites are usually geosynchronous.
Broadcast satellites transmit television signals from one point to another (similar to communication satellites).
Scientific satellites, such as the Hubble Space Telescope, carry out all kinds of scientific missions. They look at everything from sunspots to gamma rays.
Navigation satellites help ships and planes navigate. The most famous are the GPS NAVSTAR satellites.
Rescue satellites respond to radio interference signals.
Earth observation satellites checking the planet for changes in everything from temperature, forest cover, to ice cover. The most famous are the Landsat series.
Military satellites The Earths are in orbit, but much of the actual position information remains secret. Satellites could include encrypted communications relay, nuclear monitoring, surveillance of enemy movements, early warning of missile launches, eavesdropping on terrestrial radio links, radar imaging, and photography (using essentially large telescopes that photograph militarily interesting areas).

Earth from an artificial satellite in real time

Images of the earth from an artificial satellite, broadcast in real time by NASA from the International Space Station. Images are captured by four cameras high resolution, isolated from low temperatures, allowing us to feel closer to space than ever before.

The experiment (HDEV) on board the ISS was activated on April 30, 2014. It is mounted on the external cargo mechanism of the European Space Agency's Columbus module. This experiment involves several high-definition video cameras that are enclosed in a housing.

Advice; put the player in HD and full screen. There are times when the screen will be black, this can be for two reasons: the station is passing through an orbital zone where it is at night, the orbit lasts approximately 90 minutes. Or the screen goes dark when the cameras change.

How many satellites are there in Earth orbit 2018?

According to the United Nations Office for Outer Space Affairs (UNOOSA) Index of Objects Launched into Outer Space, there are currently some 4,256 satellites in Earth's orbit, up 4.39% from last year.

221 satellites were launched in 2015, the second most in a single year, although it is below the record number of 240 launched in 2014. The increase in the number of satellites orbiting the Earth is less than the number launched last year because satellites have a limited lifespan. Large communications satellites last 15 years or more, while small satellites such as CubeSats can only expect a service life of 3-6 months.

How many of these Earth orbiting satellites are operational?

The Union of Scientists (UCS) is clarifying which of these orbiting satellites are working, and it's not as much as you think! There are currently only 1,419 operational Earth satellites—only about one-third of the total number in orbit. This means there is a lot of useless metal around the planet! That's why there is a lot of interest from companies looking at how they capture and return space debris, using techniques such as space networks, slingshots or solar sails.

What are all these satellites doing?

According to UCS, the main objectives of operational satellites are:

Communications - 713 satellites
Earth observation/science - 374 satellites
Technology demonstration/development using 160 satellites
Navigation & GPS - 105 satellites
Space science - 67 satellites

It should be noted that some satellites have multiple purposes.

Who owns the Earth's satellites?

It is interesting to note that there are four main types of users in the UCS database, although 17% of satellites are owned by multiple users.

94 satellites registered by civilians: they are generally educational institutions, although there are other national organizations. 46% of these satellites have the purpose of developing technologies such as Earth and space science. Observations account for another 43%.
579 belong to commercial users: commercial organizations and government organizations that want to sell the data they collect. 84% of these satellites are focused on communications and global positioning services; of the remaining 12% are Earth observation satellites.
401 satellites are owned by government users: mainly national space organizations, but also other national and international bodies. 40% of them are communications and global positioning satellites; another 38% is focused on Earth observation. Of the remainder, the development of space science and technology accounts for 12% and 10%, respectively.
345 satellites belong to the military: again the focus here is communications, Earth observation and global positioning systems, with 89% of the satellites having one of these three purposes.

How many satellites do countries have?

According to UNOOSA, about 65 countries have launched satellites, although the UCS database only has 57 countries recorded using satellites, and some satellites are listed with joint/multinational operators. The biggest:

USA with 576 satellites
China with 181 satellites
Russia with 140 satellites
The UK is listed as having 41 satellites, plus participates in an additional 36 satellites operated by the European Space Agency.

Remember when you look!
Next time you look at the night sky, remember that between you and the stars there are about two million kilograms of metal surrounding the Earth!

Working satellites/failed/junk

As usual, click to enlarge

Scientists first started talking about large-scale space pollution in the 1980s, when the concentration of debris in Earth’s orbit reached such a density that ballisticians needed to work hard to safely place one or another satellite among it. IN last decade the situation only got worse. “The amount of debris in near-Earth space is so great that it creates real danger for the automatic stations operating there. In the near future, difficulties will grow like a snowball,” believes Alexander Bagrov, senior researcher at the Research Institute of Astronomy of the Russian Academy of Sciences. His reasons for this are very serious.

Dump in the sky - trouble on Earth

First of all, objects in orbit are, of course, affected by space debris. “Ground-based observation services sometimes record collisions of space debris particles with each other, which is why their number multiplies exponentially,” says the chairman of the commission on space debris problems of the Russian Academy of Sciences, deputy director of the Institute of Applied Mathematics. Keldysh Efraim Akim. - Small fractions pose no less danger than large ones. Just imagine a large-caliber bullet moving at a speed of 8-10 km/s. When such a particle hits an operating spacecraft, the impact force is simply monstrous. No ship could withstand such a collision. If a collision does occur, the cloud of debris in orbit will spread in all directions in just a couple of weeks, threatening to destroy other neighbors as well.”

And although the probability of failure of orbiting satellites space debris is still extremely small, there have already been unpleasant incidents, including with passenger spacecraft and orbital stations.

In 1983, the crew of the infamous Challenger shuttle discovered a small mark on the windshield of their ship from a collision with a foreign object. The crater was only 2.5 mm deep and the same width, but it made NASA engineers very worried. After the spacecraft landed, experts carefully examined the damage and came to the conclusion that the cause of the collision was a microparticle of paint that had peeled off from some other spacecraft. The Soviet orbital station Salyut-7 was also damaged by space debris, the surface of which was literally dotted with microscopic craters from collisions with debris particles. To prevent the possibility of such incidents in the future, the Mir station and the ISS that replaced it were equipped with screens that protected the habitable modules from collisions with small debris. However, this did not help either. In June 1999, the then uninhabited ISS had every chance of colliding with a fragment of the upper stage of one of the rockets, already for many years orbiting the Earth. Fortunately, specialists from the Russian Mission Control Center (MCC) managed to correct its orbit in a timely manner, and the fragment flew past at a distance of 6.5 km. In 2001, the ISS had to take a special maneuver to avoid colliding with a seven-kilogram instrument lost during a spacewalk by American astronauts. Since then, the station has been dodging space debris with enviable regularity, several times a year.

Space debris also poses a danger to earthlings far from space, falling on their heads in the literal sense of the word. In 1978, the taiga regions of northern Canada were damaged by the fall of the Soviet satellite Cosmos 594. A year later, the wreckage of the American space station Skylab scattered over the desert regions of Australia.

In 1964, during the unsuccessful launch of a US navigation satellite from nuclear sources energy on board, radioactive materials were dispersed over the Indian Ocean. Everyone remembers the situation with the Mir station, which was sunk in the Pacific Ocean. Then tens of thousands of residents of island states suffered from a fatal mass psychosis. People were terrified that the “Russian giant” would fall right on their heads. But for the residents of the Altai Territory, this nightmare has become a reality. It is over this region of Russia that the flight trajectories of rockets launched from Baikonur lie, and it is here that the debris of the first stages with the remains of highly toxic fuel lie.

But what is space debris? Where does it come from?

Who's doing the littering here?

“The situation is paradoxical,” says Alexander Bagrov. “The more we launch into space, the less usable it becomes.” Indeed, according to Russian experts, there are currently more than 10 thousand aircraft and Earth satellites in space, but only 6% of them are operational. Spacecraft fail with enviable regularity, and as a result, the density of space debris in orbit increases by 4% annually. Currently, about 70-150 thousand objects ranging in size from 1 to 10 cm revolve around our planet, and there are millions of particles less than 1 cm in diameter. “And if in low orbits, up to about 400 km, debris slows down on the upper layers of the atmosphere and eventually falls to Earth, then in geostationary orbits it can rotate indefinitely,” continues Alexander Bagrov.

The upper stages of rockets, with the help of which satellites are launched into geostationary orbits, also contribute to the increase in space debris. About 5-10% of the fuel remains in their tanks, which is very volatile and easily turns into steam, which often leads to powerful explosions. After several years in space, spent rocket stages shatter into pieces, scattering “shrapnel” of small fragments around them. For recent years 182 similar fireworks were recorded in near-Earth space. Just one recent explosion of an Indian launch vehicle stage resulted in the formation of 300 large pieces of debris and countless smaller but equally dangerous objects. The first victims have already been.

In July 1996, at an altitude of approximately 660 km, a French satellite collided with a fragment of the third stage of the French Arian rocket, launched much earlier. The relative speed at the time of the collision was about 15 km/s, or about 50,000 km/h. The French ballisticians, who missed the approach of their own large object in orbit, then bit their elbows for a long time, and for good reason. The incident did not end in a major international scandal only because both objects were of French origin. How to clear the orbit of space debris?

Space scavenger job still open

"Unfortunately, at the moment effective ways There is no such thing as destruction of space debris,” says Ephraim Akim. In his opinion, collecting debris using American shuttles is incredibly expensive, and the shuttles have been laid up for several years now. It is even more crazy to burn space debris with a laser, since the molten metal, as it cools, will turn into deadly “shrapnel” that will spread across orbit, further polluting space. It is also not yet possible to replace multi-stage rockets with reusable systems; they are too expensive. “Of course, it’s good to launch and pick up satellites using flying saucers. At any moment I took off, hooked it and landed back on Earth,” Efraim Akim laughs. - Alas, humanity is like technical devices doesn't have it. Until they appear, we need to do our best to prevent further space pollution, otherwise in the future, due to the danger of encountering space debris, its exploration will turn into a very risky undertaking.”

The only thing that scientists can offer so far is careful mapping of the space dump. But here everything is not so simple. “Today, only two states in the world are able to effectively monitor the behavior of space debris,” says Nikolai Ivanov, chief ballistician at the Mission Control Center. It’s easy to guess that these are Russia and the United States, which, by the way, are also the main “polluters” of space. “We, like America, have unique ground-based systems that make it possible to detect pieces up to several centimeters in diameter in low orbits, but it is also necessary to jointly develop measures to neutralize them. It would be nice to create an international tracking system, combine object catalogs, develop common system warnings about the risks of collisions, only in this case can flights be truly safe,” continues Nikolai Ivanov. “To avoid accidents on space roads, it is necessary to develop international rules space movement,” Efraim Akim echoes him. The first steps in this direction have already been taken.

Space traffic rules

“Several international commissions, including under the auspices of the UN, are engaged in preventing further pollution of outer space,” says Alexander Alferov, Scientific Secretary of the Space Council of the Russian Academy of Sciences. - True, they are faced with the slowness of a number of agencies who prefer to weigh everything very carefully before entering into cooperation. The fact is that many satellites belong to military departments and full information It is very difficult to get information about them. The commercial side of the issue cannot be ignored.” However, the privatization of space plays into the hands of those who advocate for its purity. “Space is gradually turning into a zone for capital investment, and businessmen have always been interested in the issues of risk insurance and compensation for losses as a result of certain force majeure circumstances,” says Alexander Bagrov. - Without developing uniform legal norms this will not be achieved. For example, who should be responsible if an old lifeless satellite or the upper stage of a rocket launched by one state rams an automatic station belonging to another country? There is no answer to this question yet, although similar precedents have already taken place.” And although private space companies are only taking their first steps, the very fact of their birth has prompted the development of uniform international rules. “Currently, new requirements for space technology, satellite operation zones are determined and methods for disposing of devices that have expired are specified,” says Efraim Akim.

One of the first real achievements in the fight against space debris was the development of new international standards for artificial Earth satellites. Now they must have reserve fuel reserves on board in order to take the devices into specially designated areas of near-Earth orbits or send them towards the Earth after the expiration of their operating life. It is also advisable to equip satellites additional systems controls capable of removing the vehicle from its working orbits if the vehicle is hit by debris particles. It is assumed that the “satellite graveyards” will be located 200-300 km above the geostationary orbit zone. “Of course, the implementation of new standards is going very slowly,” admits Efraim Akim, “because they are associated with significant costs. A change in satellite design entails additional multimillion-dollar investments, which not all aerospace corporations like. But at the moment we simply cannot do without these measures, and everyone understands this.”

Another important step is the introduction into the international rules for the use of space of a requirement to equip rocket upper stages with fuel drain systems. Once in space, after completing the maneuver, the control electronics in mandatory must open the valves and release excess fuel. Unfortunately, this is sometimes not enough. Due to the nature of the fuel and the inability to completely throw it out of the tanks, even “empty” tanks explode. This means that measures must be taken to improve the design of space rockets.

To date, space debris has been well studied. As scientists note, it is distributed in orbits in layers, like the filling of a pie. This is directly related to the functional load on a particular orbit. The more convenient it is, the more satellites work on it. After some time, some of them turn into lifeless scrap metal, polluting the space where their lives had recently passed

The first debris belt is located at an altitude of 850-1200 km from the Earth's surface. This is where it moves huge amount meteorological, military, scientific satellites and probes. The second belt of pollution lies in the region of geostationary orbits (over 30,000 km). Now there are about 800 objects there different countries. Every year 20-30 new stations join them

According to the Russian Academy of Sciences, about 85% of space debris comes from large parts of rockets and upper stages, with the help of which artificial Earth satellites are launched into orbit, as well as the spent satellites themselves

Another 12% of debris are structural elements that are separated during the launch of satellites and their operation. Everything else is small fractions and fragments resulting from their collision

4.4545454545455 Rating 4.45 (11 Votes)

Artificial satellites can be called both spacecraft built specifically to rotate around the Earth in orbit, and various objects - satellite fragments, upper stages, non-functioning vehicles, components of the last stages, which are space debris. Most often, satellites are called controlled or automatic spaceships, but other structures - for example, orbital stations, are them too.

All these objects, even those not manned, are in orbit around the Earth. In total, more than sixteen thousand different artificial objects rotate in low-Earth orbit, but only about 850 of them are functioning. It is impossible to establish the exact one, since it is constantly changing - some debris in low orbits gradually descends and falls, burning up in the atmosphere.

Most of the satellites belong to the United States, Russia takes second place in terms of their number, and China, Great Britain, Canada, and Italy are also in first place on this list.

The purpose of satellites can be different: these are meteorological stations, navigation instruments, biosatellites, warships. If earlier, at the dawn of the development of the space age, only government organizations could launch them, today there are satellites of private companies and even individuals, since the cost of this procedure has become more affordable and amounts to several thousand dollars. This explains the huge number various items moving in Earth's orbit.

The most notable satellites

The first artificial satellite was launched in 1957 by the USSR, it was called Sputnik 1, this became well-established and was even adopted by many other languages, including English. On next year The United States launched its own Explorer 1.

Then followed the launches of Great Britain, Italy, Canada, France. Today, several dozen countries around the world have their own satellites in orbit.

One of the largest projects in the history of the space age was the launch of the ISS, an international space station with research purposes. Its management is carried out by the Russian and American segments, and Danish, Canadian, Norwegian, French, Japanese, German and other cosmonauts also take part in the work of the station.

In 2009, the largest artificial satellite, Terrestar-1, an American project of a telecommunications organization, was launched into orbit. It has a huge mass - almost seven tons. Its goal is to provide connectivity for most of North America.

Have you ever wondered how many satellites orbit the Earth?

The first artificial satellite was launched into earth orbit on October 4, 1957. Over the years of space exploration, several thousand flying objects have accumulated in near-Earth space.

16,800 artificial objects fly above our heads, among them 6,000 satellites, the rest are considered space debris - these are upper stages and debris. There are fewer actively functioning devices - about 850.

AMSAT OSCAR-7, launched into orbit on November 15, 1974, is considered the longest-lived satellite. This small device (its weight is 28.8 kilograms) is intended for amateur radio communications. The largest object in orbit is the International Space Station (ISS). Its weight is about 450 tons.

Satellites that provide communications to cellular operators (Beeline, MTS and Megafon) are placed in two types of orbits: low and geostationary.

At a low altitude, 780 kilometers from Earth, there is a used...

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Universe > How many satellites are there in space?

Tracked satellites in Earth orbit

Launched on October 4, 1957 space age with the launch of the first satellite Sputnik-1. He was destined to spend 3 months in orbit and burn up in the atmosphere. Since that moment, many devices have been sent into space: in Earth orbit, around the Moon, around the Sun, other planets, and even beyond the solar system. There are 1071 operational satellites in Earth orbit alone, 50% of which are US developed.

Half are located in low Earth orbit (several hundred km). These include the International Space Station, the Hubble Space Telescope and observation satellites. A certain part is located in medium-Earth orbit (20,000 km) - satellites used for navigation. A small group enters an elliptical orbit. The rest rotate in geostationary orbit (36,000 km).

If we could see them with the naked eye, they would appear static. Their availability on...

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What is an Earth satellite?

An Earth satellite is any object that moves along a curved path around a planet. The Moon is the original, natural satellite of the Earth, and there are many artificial satellites, usually in close orbit to the Earth. The path followed by a satellite is an orbit, which sometimes takes the shape of a circle.

Earth satellite orbits

Satellite orbits

Sometimes the orbit of an Earth satellite looks like an ellipse, a squashed circle that moves around two points known as foci. The same applies...

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British scientists called ineffective public administration the most the best indicator the rate of decline in biodiversity among all anthropogenic factors. At the same time, biodiversity is rapidly declining even in officially protected areas, nature reserves and national parks.

Genetic analysis, conducted by David Schill and Nathan Hollenbeck, confirmed that in the northernmost Pacific Ocean, in the area of Alaska and the Bering Sea, lives separate species octopuses. They prefer not only cold, but also deeper waters, so they are less likely to be seen by divers.

Let us recall that at the end of November an accident occurred on the Soyuz-2.1b rocket launched from the Vostochny cosmodrome. The reason for the fall of the Fregat upper stage with 19 satellites into the Atlantic Ocean was the incorrect operation of the software algorithms.

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3D printers are the same as Forbes, only better.

Delta printers are extremely demanding on the precision of manufacturing components (frame geometry, length of diagonals, backlash in the connection of diagonals, effector and carriages) and the entire geometry of the printer. Also, if the limit switches (EndStop) are located on different heights(or a different moment of operation in the case of contact limit switches), then the height along each of the axes turns out to be different and we get an inclined plane that does not coincide with the plane of the working table (glass). These inaccuracies can be corrected either mechanically (by adjusting the height limit switches) or software. We use a software calibration method.
Next we will look at the basic settings of the delta printer.
We use the Pronterface program to control and configure the printer.
Printer calibration is divided into three stages:

Stage 1 Adjusting the plane using three points

Alignment of three...

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Moscow. December 30th. INTERFAX.RU - The problems that arose after the launch of the Angolan communications satellite Angosat were related to the compatibility of Russian and French standards of equipment on board, an informed source told Interfax.

Angosat successfully reached its stationary position in geostationary orbit. After its launch, problems arose due to “inconsistencies” between Russian and French regulations,” the source said.

He clarified that the satellite has French-made components, and difficulties have arisen with the compatibility of its standards with Russian ones.

“The problem was solved remotely by a group of young employees of RSC Energia, which developed the spacecraft,” the agency’s interlocutor said.

Angosat was launched into orbit by a Zenit rocket, which launched from the Baikonur Cosmodrome at 22.00 Moscow time on December 26. After eight minutes of normal flight, the Fregat upper stage separated from the rocket, which launched the satellite into the calculated orbit in...

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Most navigation satellite systems appeared in response to requests from the military and for a long time limited to GPS and GLONASS. However, after it became clear that data from satellites can be effectively used for peaceful purposes, the number of systems began to grow systematically.

We have studied the most significant NSSs existing today.

Active satellites: 31
Total satellites in orbit: 32

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Angosat-1 is the first Angolan telecommunications satellite, which is planned to be operated in geostationary orbit to provide communications and broadcasting in Angola, as well as other countries in Africa and southern Europe. The satellite's mass is 1647 kg. Estimated service life is 15 years.

The rocket was launched with the Angosat-1 satellite. The Zenit-3SLBF launch vehicle is one of the modifications of the Zenit launch vehicle family, developed by Yuzhnoye Design Bureau. Produced at Yuzhmash.

Satellites located in GEO rotate synchronously with the Earth, so they are constantly above a certain area. The position of the devices on the geostationary orbit is called the standing point. As the head of RSC Energia, Vladimir Solntsev, previously reported, Angosat will move to its operating point (over Africa) within two months. Now both objects discovered by NORAD are located above the equator, but much further east - at coordinates 46 and 37 degrees east longitude.

“Two new objects have been detected in orbit, related...

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The first artificial Earth satellite was launched in 1957 in the USSR. Since then, more than 6,000 satellites have been sent into space. Satellites are becoming increasingly important to life on Earth. They are used for a variety of purposes: security, communication, navigation, entertainment, and - most importantly - they allow us to see our planet in a new light. Here you can find out who owns the satellites, where they are located and what their purpose is.

Who has the most companions?

Of the total 957 operational satellites currently in orbit, 423 belong to the United States. Next in terms of number of satellites is Russia. China also has a significant presence in the orbit. At least 115 countries are co-owners of satellites. This diagram shows the countries where the owners or operators of the satellite are located.

44 countries around the world cooperate in launching and operating satellites (usually a group of two or three countries). Here they are listed as joint projects. USA, Taiwan, Japan and France...

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Geostationary orbit

The orbits in which satellite relays are located are divided into three classes:

Equatorial(1); inclined(2); polar(3).

An important variation of the equatorial orbit is the geostationary orbit, in which the satellite rotates with an angular velocity equal to angular velocity Earth, in a direction coinciding with the direction of rotation of the Earth. The obvious advantage of the geostationary orbit is that the receiver in the service area “sees” the satellite constantly.

The geostationary orbit is determined using a simple mathematical relationship: the angular velocity of the satellite's movement is equal to the angular velocity of the Earth's rotation. Despite its simplicity, this relationship holds for a single trajectory that “hangs” at a distance of slightly less than 36,000 km above the equator. In geostationary orbit, the satellite is stationary for an observer on Earth. This is the main advantage of the geostationary orbit. Therefore, the antennas are also stationary...

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India's communications satellite GSAT-1, launched on April 18 by India's first launch vehicle, failed to enter geostationary orbit due to fuel shortage.

As representatives of the Indian Space Research Organization told RIA Novosti on Wednesday, the satellite is now in orbit with a period of revolution around the Earth of 23 hours instead of the required 24 hours, so its payload cannot be used for its intended purpose.

The problem arose as a result of the fact that the two fuel tanks supplied fuel to the engines in unequal quantities, so the rocket’s flight path changed.

To level it, additional fuel was consumed, and therefore it was not enough to adjust the orbit at the last stage.

The Indians plan to carry out the next launch of a launch vehicle with a geostationary satellite in the second half of 2002...

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GPS - the beginning of global navigation

Active satellites: 31
Total satellites in orbit: 32
Average height from Earth: 22180
Time full turn around the Earth: 11 hours 58 minutes

The American system appeared in 1974 and immediately created a sensation with its effectiveness. The US government even had to artificially reduce the accuracy of coordinate determination in order to maintain advantages for its military. They got rid of the self-created difficulties only in 2000 - after Bill Clinton’s decree. Initially, the GPS architecture involved the use of 24 satellites, but for greater reliability there are 32 slots in orbit, of which 31 are constantly in use. Each satellite circles the Earth twice a day and is controlled from the Schriever military base by radio signals with a frequency of 2000-4000 MHz. GPS has been and remains the undisputed leader among similar systems and finding an NSS device without a GPS-enabled chip is quite difficult - at least in the Western Hemisphere. Despite...

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Everything you need to know about Geostationary Satellite Orbit

IN this material We'll look at the basic principles and concepts of geostationary orbit (GEO).

A very popular satellite orbit is the geostationary orbit. It is used to host many types of satellites, including direct broadcast satellites, communications satellites, and relay systems.

The advantage of geostationary orbit is that the satellite located in it is constantly located in the same position, which allows a fixed antenna of a ground station to be pointed at it.
This factor is extremely important for systems such as direct broadcast via satellite, where the use of a constantly moving antenna following the satellite would be extremely impractical.

Care must be taken when using abbreviations for geostationary orbit. We may come across the abbreviations GEO and GSO, and...

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