ORBIT
in astronomy, the way celestial body in space. Although the orbit can be called the trajectory of any body, they usually mean the relative motion of bodies interacting with each other: for example, the orbits of planets around the Sun, satellites around a planet, or stars in a complex star system relatively common center wt. An artificial satellite "goes into orbit" when it begins to move in a cyclic trajectory around the Earth or the Sun. The term "orbit" is also used in atomic physics when describing electronic configurations.
see also ATOM.
Absolute and relative orbits. An absolute orbit is the path of a body in a frame of reference, which in a sense can be considered universal and therefore absolute. The Universe is considered to be such a system. large scale, taken as a whole, and called it "inertial system". A relative orbit is the path of a body in such a frame of reference, which itself moves along an absolute orbit (along a curved trajectory with a variable speed). For example, at the orbit artificial satellite usually indicate the size, shape and orientation relative to the Earth. In the first approximation, this is an ellipse, the focus of which is the Earth, and the plane is stationary relative to the stars. Obviously, this is a relative orbit, since it is defined in relation to the Earth, which itself moves around the Sun. A distant observer will say that the satellite moves relative to the stars along a complex helical trajectory; this is its absolute orbit. It is clear that the shape of the orbit depends on the motion of the observer's frame of reference. The need to distinguish between absolute and relative orbits arises because Newton's laws are true only in inertial system reference, so they can only be used for absolute orbits. However, we are always dealing with the relative orbits of celestial bodies, because we observe their movement with the Earth revolving around the Sun and rotating around it. But if the absolute orbit of the terrestrial observer is known, then it is possible either to convert all relative orbits into absolute ones, or to represent Newton's laws by equations that are true in the Earth's frame of reference. The absolute and relative orbits can be illustrated by the example double star. For example, Sirius, which appears to the naked eye as a single star, when viewed from large telescope turns out to be a pair of stars. The path of each of them can be traced separately in relation to neighboring stars (taking into account that they themselves are moving). Observations have shown that two stars not only revolve around one another, but also move in space so that there is always a point between them moving in a straight line at a constant speed (Fig. 1). This point is called the center of mass of the system. In practice, an inertial frame of reference is connected with it, and the trajectories of stars relative to it represent their absolute orbits. The farther away a star is from its center of mass, the lighter it is. Knowing the absolute orbits allowed astronomers to calculate separately the masses of Sirius A and Sirius B.
If we measure the position of Sirius B relative to Sirius A, then we get a relative orbit (Fig. 2). The distance between these two stars is always equal to the sum of their distances from the center of mass, so the relative orbit has the same shape as the absolute ones, and is equal in size to their sum. Knowing the size of the relative orbit and the period of revolution, it is possible, using Kepler's third law, to calculate only the total mass of the stars.
see also HEAVENLY MECHANICS.
A more complex example is the motion of the Earth, Moon and Sun. Each of these bodies moves in its absolute orbit relative to the common center of mass. But since the Sun greatly outnumbers everyone else in mass, it is customary to depict the Moon and Earth as a pair, the center of mass of which moves in a relative elliptical orbit around the Sun. However, this relative orbit is very close to absolute.
see also MOON . The motion of the Earth relative to the center of mass of the Earth-Moon system is most accurately measured using radio telescopes that determine the distance to interplanetary stations. In 1971, during the flight of the Mariner-9 apparatus to Mars, the amplitude of the Earth's motion was determined by periodic variations in the distance to it with an accuracy of 20-30 m. The center of mass of the Earth-Moon system lies inside the Earth, 1700 km below its surface, and the ratio of the Earth's masses and the moon is 81.3007. Knowing their total mass, found from the parameters of the relative orbit, one can easily find the mass of each of the bodies. Speaking of relative motion, we can arbitrarily choose a reference point: the relative orbit of the Earth around the Sun is exactly the same as the relative orbit of the Sun around the Earth. The projection of this orbit onto the celestial sphere is called the "ecliptic". During the year, the Sun moves along the ecliptic by about 1 ° per day, and when viewed from the Sun, the Earth moves in exactly the same way. The plane of the ecliptic is inclined to the plane celestial equator at 23 ° 27", i.e. this is the angle between the earth's equator and its orbital plane. All orbits in the solar system point relative to the plane of the ecliptic.
Orbits of the Moon and planets. Using the example of the Moon, we will show how the orbit is described (Fig. 3). This is a relative orbit, the plane of which is inclined by about 5° to the ecliptic. This angle is called the "inclination" of the lunar orbit. The plane of the lunar orbit crosses the ecliptic along the "line of nodes". The one where the Moon passes from south to north is called the "ascending node", and the other is called the "descending node".
If the earth and moon were isolated from gravitational influence other bodies, the nodes of the lunar orbit would always have a fixed position in the sky. But due to the influence of the Sun on the movement of the Moon, the reverse movement of the nodes occurs, i.e. they move along the ecliptic to the west, making a complete revolution in 18.6 years. Similarly, the nodes of the orbits of artificial satellites move due to the perturbing influence of the equatorial bulge of the Earth. The Earth is located not in the center of the lunar orbit, but in one of its focuses. Therefore, at some point in the orbit, the Moon is closest to the Earth; this is "perigee". AT opposite point it is farthest from the earth; it's "apogee". (The corresponding terms for the Sun are "perihelion" and "aphelion".) The half-sum of the distances at perigee and apogee is called the mean distance; it is equal to half largest diameter(major axis) of the orbit, which is why it is called the "major axis". The perigee and apogee are called "apses", and the line connecting them - the major axis - is called the "line of apses". If it were not for disturbances from the Sun and planets, the line of apsides would have a fixed direction in space. But due to perturbations, the line of apsides of the lunar orbit moves to the east with a period of 8.85 years. The same happens with the lines of apsides of artificial satellites under the influence of the equatorial swelling of the Earth. In planets, the lines of apsides (between perihelion and aphelion) move forward under the influence of other planets.
see also CONIC SECTIONS . The size of an orbit is determined by the length of the semi-major axis, and its shape by a quantity called "eccentricity". The eccentricity of the lunar orbit is calculated by the formula: (Distance at apogee - Average distance) / Average distance or by the formula (Average distance - Distance at perigee) / Average distance For planets, apogee and perigee in these formulas are replaced by aphelion and perihelion. Eccentricity of a circular orbit zero; for all elliptical orbits it is less than 1.0; for a parabolic orbit, it is exactly 1.0; for hyperbolic orbits it is greater than 1.0. An orbit is fully defined if its size (mean distance), shape (eccentricity), inclination, position of the ascending node, and position of perigee (for the Moon) or perihelion (for planets) are specified. These quantities are called "elements" of the orbit. The elements of the orbit of an artificial satellite are set in the same way as for the Moon, but usually with respect not to the ecliptic, but to the plane of the earth's equator. The Moon revolves around the Earth in a time called the "sidereal period" (27.32 days); after its expiration, it returns to its original place relative to the stars; this is its true orbital period. But during this time, the Sun moves along the ecliptic, and the Moon needs two more days to be in the initial phase, i.e. in its original position relative to the sun. This period of time is called the "synodic period" of the Moon (about 29.5 days). Likewise, the planets revolve around the Sun in a sidereal period, and full cycle configurations - from "evening star" to " morning star" and back - for the synodic period. Some elements of the orbits of the planets are indicated in the table.
see also SOLAR SYSTEM .
orbital speed. The average distance of the satellite from the main component is determined by its speed at some fixed distance. For example, the Earth revolves in an almost circular orbit at a distance of 1 AU. ( astronomical unit) from the Sun at a speed of 29.8 km/s; any other body having the same speed at the same distance will also move in an orbit with an average distance from the Sun of 1 AU, regardless of the shape of this orbit and the direction of movement along it. Thus, for a body in given point the size of the orbit depends on the value of the velocity, and its shape depends on the direction of the velocity (Fig. 4).
This is directly related to the orbits of artificial satellites. To put a satellite into a given orbit, it is necessary to deliver it to certain height over the Earth and tell him a certain speed in a certain direction. Moreover, this must be done with high accuracy. If it is required, for example, that the orbit passes at an altitude of 320 km and does not deviate from it by more than 30 km, then at an altitude of 310-330 km its speed should not differ from the calculated one (7.72 km / s) by more than 5 m /s, and the direction of speed must be parallel earth's surface with an accuracy of 0.08°. The above applies to comets as well. Usually they move in very elongated orbits, the eccentricities of which often reach 0.99. And although their average distances and orbital periods are very large, at perihelion they can approach big planets like Jupiter. Depending on the direction from which the comet approaches Jupiter, it can increase or decrease its speed by its attraction (Fig. 5). If the speed decreases, then the comet will move to a smaller orbit; in this case, it is said to be "captured" by the planet. All comets with periods less than a few million years have probably been captured in this way.
Rice. 5. CAPTURE OF A COMET BY JUPITER. Comet C, passing in front of Jupiter, slows down and passes into a smaller orbit ("captured"). Comet E, passing behind Jupiter, is accelerating relative to the Sun.
If the comet's speed relative to the Sun increases, then its orbit will also increase. Moreover, as the speed approaches a certain limit, the growth of the orbit rapidly accelerates. At a distance of 1 AU from the Sun, this limiting velocity is 42 km/s. FROM more speed the body moves in a hyperbolic orbit and never returns to perihelion. Therefore, this limiting speed is called the "escape speed" from the earth's orbit. Closer to the Sun, the escape velocity is higher, and far from the Sun, it is lower. If a comet is approaching Jupiter from a great distance, its speed is close to its escape velocity. Therefore, flying near Jupiter, it is enough for a comet to slightly increase its speed in order to exceed the limit and never again return to the vicinity of the Sun. Such comets are called "ejected".
escape velocity from the earth. The concept of escape velocity is very important. By the way, it is often also called the "escape" or "escape" speed, and also "parabolic" or "second cosmic speed". The latter term is used in astronautics when we are talking about launches to other planets. As already mentioned, for the movement of a satellite in a low circular orbit, it needs to be informed of a speed of about 8 km / s, which is called the "first space one". (More precisely, if the atmosphere had not interfered, it would have been equal to 7.9 km / s at the Earth's surface.) As the satellite's speed near the Earth's surface increases, its orbit becomes more and more elongated: its average distance increases. When the escape velocity is reached, the spacecraft will leave Earth forever. Calculating this critical speed is quite simple. Close to Earth kinetic energy body should be equal to the work of gravity when moving the body from the surface of the Earth "to infinity". Since attraction decreases rapidly with height (inversely proportional to the square of the distance), we can restrict ourselves to working at a distance of the radius of the Earth:
Here on the left is the kinetic energy of a body of mass m moving at a speed V, and on the right is the work of gravity mg at a distance of the Earth's radius (R = 6371 km). From this equation we find the speed (and this is not an approximate, but its exact expression):
Since the acceleration free fall at the Earth's surface is g = 9.8 m/s2, the escape velocity will be equal to 11.2 km/s.
Orbit of the Sun. The Sun itself, together with the surrounding planets and small bodies solar system moves on its own galactic orbit. In relation to the nearest stars, the Sun flies at a speed of 19 km / s towards a point in the constellation Hercules. This point is called the "apex" of solar motion. On the whole, the entire group of nearby stars, including the Sun, revolves around the center of the Galaxy in an orbit with a radius of 25*10 16 km at a speed of 220 km/s and a period of 230 million years. This orbit has quite complex view, because the motion of the Sun is constantly being perturbed by other stars and massive clouds of interstellar gas.
Collier Encyclopedia. - Open Society. 2000 .
Synonyms:See what "ORBIT" is in other dictionaries:
- (lat., from orbis circle). 1) way heavenly body. 2) eye orbits - hollows in which the eyes are placed. Dictionary foreign words included in the Russian language. Chudinov A.N., 1910. ORBIT 1) the path of a celestial body; 2) eye about. cavity, in ... ... Dictionary of foreign words of the Russian language
The name of the television channels operating in Siberia. Broadcast to the territory of the Novosibirsk, Tomsk, Kemerovo regions, Alatay and Krasnoyarsk territories and the republics of Altai, Khakassia, the east of Kazakhstan. Orbit 4 . Name of TV channels ... Wikipedia
orbit- uh. orbite f. , lat. orbita. 1. The path along which a celestial body moves under the influence of the attraction of other celestial bodies. ALS 1. The length of the axes of circles (orbites). AI 1780 6 262. Finally, if, in the absence of a micrometer, the observer managed to notice ... ... Historical dictionary gallicisms of the Russian language
For some reason, it is generally accepted that only boys want to be astronauts. Not true! Since childhood, I dreamed of being in space, looking at our planet from above. Or even go to other planets. Dreams, unfortunately, remained dreams, but the knowledge of what an orbit is and how astronauts live there was firmly imprinted in my head.
What is an orbit
As you know, all cosmic bodies (planets, like our Earth) or their satellites (like the Moon) do not stand still, but are constantly moving.
The earth and other planets in the solar system revolve around the sun. They do this not as they please, but over and over again go the same way. It's called an orbit.
People have been exploring space for a long time, and in our time they can already be in orbit. But life there is different from what we are used to on Earth.
Life in orbit
In orbit, you can't just go outside for a walk spaceship or from a space station.
There are several reasons for this:
- The first is sudden changes in temperature. Imagine that in a fraction of a second you are teleported from the far north to a hot beach, and then back. Now increase the temperature spread by a factor of two or three. Even the most prepared person cannot withstand such overloads.
- The second is radiation and ultraviolet. On Earth, the atmosphere carefully saves us from them - and then on hot days you can get badly burned even with sunscreen. And in space, no cream will save you from the Sun.
- The third, most important, is oxygen, or rather, its absence. Without breath there is no life. Hold your breath - how long can you last? A minute or two, hardly more. This is too small for space exploration.
The spacesuit reliably protects from all this. Luckily, most time, you can wear more comfortable clothes.
No less complexities with liquids. Space and disgust are incompatible: all liquid waste products are carefully collected, after which a new portion of water for astronauts is obtained from them. No spring or river was foreseen here, and the Milky Way is associated with milk only because of the external resemblance.
Eating has become a little easier than before. Tubes have already been abandoned, but the food is still made and packaged so as not to leave a single crumb. Even such a small amount can create serious problems if it flies into Airways one of the space crew.
This is not the only disadvantage of weightlessness: you simply get tired physically from it. That is why everyone who wants to go into space must have perfect health. Otherwise, overloads cannot be sustained, all diseases will become aggravated.
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As a child, leafing through the encyclopedia, I especially liked to read about space and other planets. At first, I was very surprised that some lines were drawn around the planets, signed with the incomprehensible word “orbit”. I immediately started reading the article to understand what it is.
What is an orbit
You and I have a choice which way to go to one place or another. You can go straight, you can find a shorter way. In this regard, the planets have trouble with free will: under the influence of gravity, it cannot turn off a certain path.
An orbit is a trajectory along which one celestial body moves relative to another. For example, this is the path along which the Earth and other planets of the solar system revolve around the sun.
The first living beings in orbit
Strictly speaking, the very first living beings that found themselves in the orbit of our planet were bacteria. Of course, they were not sent there on purpose. But in the process of space exploration, the first rockets flew there, which, willy-nilly, took these miniature passengers with them.
Then, on purpose, the Americans sent fruit flies there. And they survived! So, it's time to send bigger creatures.
For a new flight into space, a monkey was chosen, because they are close in structure to humans. And if the monkey returned unharmed, sending a man into space would not be long in coming. Alas, these dreams were not yet destined to come true.
The dog Laika also deserves mention. She was the first terrestrial animal to reach the Earth's orbit. Unfortunately, the dog could not withstand the overload, and could not return alive.
Everything worked out only in 1960, when two dogs entered orbit - Belka and Strelka. After much preparation and careful selection they left the Earth, and after spending a day in orbit, they successfully returned home.
Arrow, a couple of months after the flight, even managed to give birth to healthy puppies.
Can living beings reproduce in orbit
Everything here is not as simple as it seems.
So far, conception in space is considered impossible. Sex cells due to cosmic radiation stop working as they should. As a result, the egg is not fertilized, which means that you cannot have a child.
They tried to bring living human embryos into space, they died there.
However, there is hope. In 1990, a quail chick hatched from an egg fertilized on Earth on the Mir spacecraft.
In the end, the path to orbit was not easy and short either, so it's worth waiting and hoping - and maybe one day we will be able to live in orbit.
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Since childhood, I have been interested in space, and I have an idea about what an orbit is. I will try to briefly answer the question and tell you what are satellite orbits.
What does the term "orbit" mean?
talking in plain language, it's a path in space, along which our planet moves, making a revolution around the star - the Sun. Concerning scientific definition this term, it is as follows: trajectory that describes a celestial body, being in interaction with another body or bodies. If you are careful, you can find that almost everything in our world moves in its orbit - a tiny an electron revolves around the nucleus of an atom- the basis of all material.
Satellite orbits
The trajectory of each satellite is different from the orbit of a natural celestial body. The difference is that satellites have so-called "active sites"- points at the passage of which jet engines are switched on. Therefore, the calculation of such a trajectory is a rather laborious and responsible task, which is being solved by astrodynamic scientists. At the same time, each trajectory is assigned a certain status, determined by the purpose of the apparatus, the size of the territory it covers, and much more. There are 3 types of satellite systems:
- departmental;
- national;
- international.
In addition, there is another classification of all satellites according to the type of orbit:
- geostationary- AES is located above the equator and moves at the speed of the planet around its axis;
- non-geostationary- have an elliptical, low-orbit and medium-altitude orbit.
There is also a special "burial orbit". Here, at an altitude of more than 250 kilometers above geostationary upholstery send satellites whose service life has already expired. This is done in order to avoid collisions, as well as free up space for a new device.
Unusual satellites in orbit
A few years after launch first satellite The USSR, the USA launched a communications satellite. It is noteworthy that representing « Balloon» made of metal, it was not inferior in size to an 11-storey building - 32 meters in diameter.
Typically, devices serve for several years, but there are exceptions. AES LAGEOS launched into orbit with a "service" time of 7 million years. On board there is a special plate that contains a message to future generations of earthlings.
"Estonian sailboat"- such an unofficial name was given to the device ESTCube. This is the first craft to use the "electric sail" technology. Technology is in progress practice tests and, if successful, will allow the devices develop tremendous acceleration. For example, a device with such a "sail" will reach the edge of the solar system in just 8 years.
On board the well-known ISS is installed multiple cameras, and anyone can feel like an astronaut and admire the view of our planet from orbit without leaving home. I like to look at our planet from space sometimes. :)
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From the school bench, I remembered that the orbit is the trajectory of the movement of an object in outer space. A little later, when my passion for astronomy reached the point of buying huge amount scientific journals and encyclopedias, I really delved into the study space mysteries, some of which are ready to tell you today. :)
Orbit is the way
In essence, an orbit is the path of any celestial body in space. Most often, this refers to the interaction space bodies: the planets of the solar system revolving around the sun or, for example, the moon revolving around the earth. At the same time, an artificial satellite also has an orbit (in most cases it is elongated), which revolves around a planet or star.
Orbits are of four types:
- round (rare);
- in the form of an ellipse (the most common, this includes our solar system);
- in the form of a parabola;
- in the form of a hyperbole.
If we talk about the speed of rotation of the body in orbit in the solar system, then the closer it is to the Sun, the faster it makes a circle around it.
Planet Collision
Oh, this is a favorite topic of science fiction writers! In fact, each of the planets has its own path, so they will not be able to collide. :)
Being engaged in the study of cosmic bodies, astronomers came to the conclusion that their orbits do not change. In addition to calming the alarmists, this knowledge helps to calculate and predict the position of absolutely any cosmic body at any given time! Actually, this is how scientists learn about solar eclipses and the places from where they are visible in all their glory. :)
It just so happened historically that movement in space depends on gravity. That is why all objects in the Universe move in their orbits: the Earth attracts the Moon, and the Sun - the Earth.
We are all moving along an unthinkable trajectory on a rotating planet, which, in addition, is circling not only around its axis, but also around the Sun. The Sun at this time flies around the center of the Galaxy, and the latter - around the center of the Metagalaxy, and all this aggregate flies no one knows where from the center of the unknown Universe. :)
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I have always liked to look starry sky. I remember as a child, I was not allowed to walk until dark, so I sat on the balcony and looked at the mysterious twinkling points, wondering where the ancient Greeks could see a bear or a snake. And I also wanted to see black hole… Fly to Mars, see where the universe ends and what is beyond it :) I haven’t succeeded yet, but something about distant stars I found out anyway.
Orbit in astronomy
In astronomy, this is the movement of something (for example, planets, satellites) in the gravitational field of another object that surpasses it in mass. That is, roughly speaking, when something light revolves around something heavy. For example, around heavy Mars, its sinister satellites Phobos and Deimos (their names are translated as fear and horror) dance around. Or - all the planets of the solar system clearly follow their orbits around massive star.
It's hard to imagine, but even wayward comets obey their orbits.
What are the orbits
It would seem that they tied a cow to a peg, so she walks along her “orbit” in the form of a circle. But with cosmic bodies it is a little different, although there is also a similarity. The peg for them is the “center of mass” (the same heavyweight that I spoke about earlier), but they will have much more “silushki”. Therefore, there are orbits such as:
- circle;
- ellipse (this is when our “space cow” tries to escape, stretches the rope, but it doesn’t work);
- parabolas or hyperbolas (and here it turns out that the “cow” was lassoed, she ran part of the circle in bewilderment, and then nevertheless rushed away, breaking the fetters).
artificial satellites
How great it is that people have learned to put artificial satellites into orbit around the planet. Now telescopes are spinning there, whole scientific stations and thousands of devices that help us talk to each other on the phone and determine our location.
But the matter is not simple. To make a satellite revolve around the Earth, it must be accelerated to 8 km / s or 480 km / h. This speed is called the "first space" and is the minimum for "delivery" into orbit.
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We have all heard the term orbit, and many do not even have a clue what it means. This term is used to describe the path of movement of some small celestial body in gravity more than large object. For example, our planet moves along a trajectory around the Sun, and the Moon moves around the Earth. The trajectory is rarely perfectly round, much more often its shape can be called elliptical or oval. The very meaning of the term "orbit" is translated as "path".
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In 1928 .
Benefits of geostationary orbit received wide popularity after the publication of Arthur C. Clarke's popular science article in the Wireless World magazine in 1945, therefore, in the West, geostationary and geosynchronous orbits are sometimes called " Clark's orbits", a " Clark's belt» name area outer space at a distance of 36,000 km above sea level in the plane of the earth's equator, where the orbital parameters are close to geostationary. The first satellite successfully launched into the GSO was Syncom-3 , launched by NASA in August 1964.
standing point
Calculation of parameters of the geostationary orbit
Orbit radius and orbit height
In geostationary orbit, the satellite does not approach the Earth and does not move away from it, and in addition, while rotating with the Earth, it is constantly located above any point on the equator. Therefore, the forces of gravity and centrifugal force acting on the satellite must balance each other. To calculate the height of the geostationary orbit, you can use the methods classical mechanics and, passing to the satellite's frame of reference, proceed from next equation:
F u = F Γ (\displaystyle F_(u)=F_(\Gamma )),where F u (\displaystyle F_(u))- the force of inertia, and in this case, the centrifugal force; F Γ (\displaystyle F_(\Gamma ))- gravitational force. The magnitude of the gravitational force acting on the satellite can be determined from Newton's law of universal gravitation:
F Γ = G ⋅ M 3 ⋅ m c R 2 (\displaystyle F_(\Gamma )=G\cdot (\frac (M_(3)\cdot m_(c))(R^(2)))),where is the mass of the satellite, M 3 (\displaystyle M_(3)) is the mass of the Earth in kilograms, G (\displaystyle G) is the gravitational constant, and R (\displaystyle R) is the distance in meters from the satellite to the center of the Earth or, in this case, the radius of the orbit.
Value centrifugal force s is equal to:
F u = m c ⋅ a (\displaystyle F_(u)=m_(c)\cdot a),where a (\displaystyle a)- centripetal acceleration that occurs during circular motion in orbit.
As you can see satellite mass m c (\displaystyle m_(c)) is present as a factor in the expressions for the centrifugal force and for the gravitational force, that is, the height of the orbit does not depend on the mass of the satellite, which is true for any orbits and is a consequence of the equality of the gravitational and inertial mass . Consequently, the geostationary orbit is determined only by the height at which the centrifugal force will be equal in absolute value and opposite in direction to the gravitational force created by the Earth's attraction at a given height.
The centripetal acceleration is:
a = ω 2 ⋅ R (\displaystyle a=\omega ^(2)\cdot R),where is the angular velocity of the satellite, in radians per second.
Let's make one important clarification. In fact, centripetal acceleration has physical meaning only in the inertial frame of reference, while the centrifugal force is the so-called imaginary force and takes place exclusively in frames of reference (coordinates) that are associated with rotating bodies. The centripetal force (in this case, the force of gravity) causes centripetal acceleration. The absolute value of the centripetal acceleration in the inertial frame of reference is equal to the centrifugal in the frame of reference associated in our case with the satellite. Therefore, further, taking into account the remark made, we can use the term "centripetal acceleration" together with the term "centrifugal force".
Equalizing the expressions for gravitational and centrifugal forces with the substitution of centripetal acceleration, we obtain:
m c ⋅ ω 2 ⋅ R = G ⋅ M 3 ⋅ m c R 2 (\displaystyle m_(c)\cdot \omega ^(2)\cdot R=G\cdot (\frac (M_(3)\cdot m_(c ))(R^(2)))).Reducing m c (\displaystyle m_(c)), translating R 2 (\displaystyle R^(2)) to the left, and ω 2 (\displaystyle \omega ^(2)) to the right, we get:
R 3 = G ⋅ M 3 ω 2 (\displaystyle R^(3)=G\cdot (\frac (M_(3))(\omega ^(2)))) R = G ⋅ M 3 ω 2 3 (\displaystyle R=(\sqrt[(3)](\frac (G\cdot M_(3))(\omega ^(2))))).You can write this expression differently, replacing G ⋅ M 3 (\displaystyle G\cdot M_(3)) on the µ (\displaystyle \mu )- geocentric gravitational constant:
R = μ ω 2 3 (\displaystyle R=(\sqrt[(3)](\frac (\mu )(\omega ^(2)))))Angular velocity ω (\displaystyle \omega ) is calculated by dividing the angle traveled in one revolution ( 360 ∘ = 2 ⋅ π (\displaystyle 360^(\circ )=2\cdot \pi ) radians) for the period of revolution (the time for which one complete revolution is made in the orbit: one sidereal day, or 86,164 seconds). We get:
ω = 2 ⋅ π 86164 = 7 , 29 ⋅ 10 − 5 (\displaystyle \omega =(\frac (2\cdot \pi )(86164))=7.29\cdot 10^(-5)) rad/sThe resulting orbital radius is 42,164 km. Subtracting the Earth's equatorial radius, 6,378 km, gives us a height of 35,786 km.
You can do the calculations in other ways. The height of the geostationary orbit is that distance from the center of the Earth where the angular velocity of the satellite, which coincides with the angular velocity of the Earth's rotation, generates an orbital (linear) velocity equal to the first space velocity (to ensure a circular orbit) at a given altitude.
Linear velocity of a satellite moving at angular velocity ω (\displaystyle \omega ) on distance R (\displaystyle R) from the center of rotation is
v l = ω ⋅ R (\displaystyle v_(l)=\omega \cdot R)First space velocity on distance R (\displaystyle R) from an object of mass M (\displaystyle M) is equal to
v k = G M R ; (\displaystyle v_(k)=(\sqrt (G(\frac (M)(R))));)Equating the right-hand sides of the equations to each other, we arrive at the previously obtained expression radius GSO:
R = G M ω 2 3 (\displaystyle R=(\sqrt[(3)](G(\frac (M)(\omega ^(2))))))Orbital speed
The speed of movement in geostationary orbit is calculated by multiplying angular velocity per orbit radius:
v = ω ⋅ R = 3 , 07 (\displaystyle v=\omega \cdot R=3(,)07) km/sThis is about 2.5 times less than the first cosmic velocity, equal to 8 km/s per earth orbit(with a radius of 6400 km). Since the square of the speed for a circular orbit is inversely proportional to its radius,
v = G M R ; (\displaystyle v=(\sqrt (G(\frac (M)(R))));)then a decrease in velocity with respect to the first space velocity is achieved by increasing the radius of the orbit by more than 6 times.
R ≈ 6400 ⋅ (8 3 , 07) 2 ≈ 43000 (\displaystyle R\approx \,\!(6400\cdot \left((\frac (8)(3(,)07))\right)^(2 ))\approx\,\!43000)Orbit length
Geostationary orbit length: 2 ⋅ π ⋅ R (\displaystyle (2\cdot \pi \cdot R)). With an orbit radius of 42,164 km, we obtain an orbit length of 264,924 km.
The length of the orbit is extremely important for calculating the "station points" of the satellites.
Maintaining a satellite in orbital position in geostationary orbit
A satellite circulating in a geostationary orbit is under the influence of a number of forces (perturbations) that change the parameters of this orbit. In particular, such perturbations include gravitational lunisolar perturbations, the effect of inhomogeneity gravitational field Earth, the ellipticity of the equator, etc. The degradation of the orbit is expressed in two main phenomena:
1) The satellite is displaced along the orbit from its original orbital position towards one of four points stable equilibrium, so-called. "Geostationary orbit potential pits" (their longitudes are 75.3°E, 104.7°W, 165.3°E, and 14.7°W) over the Earth's equator;
2) The inclination of the orbit to the equator increases (from the initial 0) at a rate of about 0.85 degrees per year and reaches maximum value 15 degrees in 26.5 years.
To compensate for these disturbances and keep the satellite at the designated position, the satellite is equipped with a propulsion system (chemical or electric rocket). Periodic switching on of thrusters (correction "north - south" to compensate for the growth of inclination of the orbit and "west - east" to compensate for drift along the orbit) keeps the satellite at the designated position. Such inclusions are made several times in 10 - 15 days. It is significant that the north-south correction requires a much larger increment in the characteristic velocity (about 45 - 50 m/s per year) than for the longitudinal correction (about 2 m/s per year). To ensure the correction of the satellite's orbit throughout the entire period of its operation (12 - 15 years for modern television satellites), a significant supply of fuel on board is required (hundreds of kilograms in the case of a chemical engine). The satellite's chemical rocket engine has a displacement fuel supply (pressure gas - helium), operates on long-term high-boiling components (usually asymmetric dimethylhydrazine and dinitrogen tetroxide). A number of satellites are equipped with plasma engines. Their thrust is significantly less in relation to chemical ones, however, their greater efficiency allows (due to long work, measured in tens of minutes for a single maneuver) to radically reduce the required mass of fuel on board. The choice of the type of propulsion system is determined by specific technical features apparatus.
The same propulsion system is used, if necessary, to maneuver the satellite to another orbital position. In some cases (usually at the end of the satellite's life), in order to reduce fuel consumption, the north-south orbit correction is stopped, and the remaining fuel is used only for the west-east correction.
The fuel reserve is the main limiting factor in the lifetime of a satellite in geostationary orbit (apart from failures of the components of the satellite itself).
Disadvantages of geostationary orbit
signal delay
Communication via geostationary satellites is characterized by long delays in signal propagation. With an orbital height of 35,786 km and a speed of light of about 300,000 km/s, the path of the Earth-satellite beam requires about 0.12 s. Beam path "Earth (transmitter) → satellite → Earth (receiver)" ≈0.24 s. The total latency (measured by the Ping utility) when using satellite communications for receiving and transmitting data will be almost half a second. Taking into account the signal delay in satellite equipment, in equipment and in cable transmission systems of terrestrial services, the total signal delay on the route “signal source → satellite → receiver” can reach 2 - 4 seconds. Such a delay makes it difficult to use GSO satellites in telephony and makes it impossible to use satellite communications using GSO in various real-time services (for example, in online games).
GSO invisibility from high latitudes
Since the geostationary orbit is not visible from high latitudes(approximately from 81° to the poles), and at latitudes above 75° observed very low above the horizon (at real conditions satellites are simply hidden by protruding objects and terrain) and only a small part of the orbit is visible ( see table), then in high-latitude regions Far North(Arctic) and Antarctica it is impossible to communicate and broadcast using the GSO. For example, American polar explorers at the Amundsen-Scott station to communicate with outside world(telephony, Internet) use a fiber optic cable 1670 kilometers long to located at 75 ° S. sh. french station
What is "Orbit"? How to spell correctly given word. Concept and interpretation.
Orbit in astronomy, the path of a celestial body in space. Although an orbit can be called the trajectory of any body, they usually mean the relative movement of bodies interacting with each other: for example, the orbits of planets around the Sun, satellites around a planet, or stars in a complex star system relative to a common center of mass. An artificial satellite "goes into orbit" when it begins to move in a cyclic trajectory around the Earth or the Sun. The term "orbit" is also used in atomic physics to describe electronic configurations. See also ATOM. Absolute and relative orbits. An absolute orbit is the path of a body in a frame of reference, which in a sense can be considered universal and therefore absolute. Such a system is considered the Universe on a large scale, taken as a whole, and is called an "inertial system". A relative orbit is the path of a body in such a frame of reference, which itself moves along an absolute orbit (along a curved trajectory with a variable speed). For example, the orbit of an artificial satellite is usually indicated by the size, shape and orientation relative to the Earth. In the first approximation, this is an ellipse, the focus of which is the Earth, and the plane is stationary relative to the stars. Obviously, this is a relative orbit, since it is defined in relation to the Earth, which itself moves around the Sun. A distant observer will say that the satellite moves relative to the stars along a complex helical trajectory; this is its absolute orbit. It is clear that the shape of the orbit depends on the motion of the observer's frame of reference. The need to distinguish between absolute and relative orbits arises because Newton's laws are true only in an inertial frame of reference, so they can only be used for absolute orbits. However, we are always dealing with the relative orbits of celestial bodies, because we observe their movement with the Earth revolving around the Sun and rotating around it. But if the absolute orbit of the terrestrial observer is known, then it is possible either to convert all relative orbits into absolute ones, or to represent Newton's laws by equations that are true in the Earth's frame of reference. The absolute and relative orbits can be illustrated by the example of a binary star. For example, Sirius, which appears to the naked eye as a single star, when observed with a large telescope, turns out to be a pair of stars. The path of each of them can be traced separately in relation to neighboring stars (taking into account that they themselves are moving). Observations have shown that two stars not only revolve around one another, but also move in space so that between them there is always a point moving in a straight line at a constant speed (Fig. one). This point is called the center of mass of the system. In practice, an inertial frame of reference is connected with it, and the trajectories of stars relative to it represent their absolute orbits. The farther away a star is from its center of mass, the lighter it is. Knowing the absolute orbits allowed astronomers to calculate the masses of Sirius A and Sirius B separately. 1. ABSOLUTE ORBIT of Sirius A and Sirius B according to observations for 100 years. The center of mass of this binary star moves in a straight line in an inertial frame of reference; therefore, the trajectories of both stars in this system are their absolute orbits.
Orbit- ORBIT lat. astron. circular path of the planet around the sun; kru "barn. doctor. eye orbit, cavity ... Dahl's Explanatory Dictionary
Orbit- ORBIT, orbits, w. (Latin orbita, lit. wheel track) (book). 1. The path of movement of a celestial body (ast ... Explanatory Dictionary of Ushakov
Orbit- and. 1. The path along which a celestial body moves under the influence of the attraction of other celestial bodies. // Way... Efremova's Explanatory Dictionary
Orbit- ORBIT (from the Latin orbita - track, path), 1) the path along which one celestial body (planet, its spin ...
orbit
Dictionary of medical terms
Explanatory Dictionary of the Living Great Russian Language, Vladimir Dal
orbit
and. lat. astron. circular path of the planet around the sun; kru "sheep.
doctor. eye orbit, cavity, fossa, hole in which the apple lies. Orbital data, elements used to calculate the path of a planet.
Explanatory dictionary of the Russian language. D.N. Ushakov
orbit
orbits, (Latin orbita, lit. wheel track) (book).
The path of movement of a celestial body (astro). Earth orbit. Earth orbit.
The same as the eye socket in 1 digit. The eyes popped out of their sockets. Orbit of influence (book) - sphere, area of influence of someone.
Explanatory dictionary of the Russian language. S.I. Ozhegov, N.Yu. Shvedova.
orbit
The path of movement of a celestial body, as well as a spacecraft, an apparatus in the gravitational field of some kind. celestial body. Earth Island heliocentric island. Launch the spacecraft into the desired orbit.
trans., what. Sphere of action, activity (book). O. influence.
Same as eyeball. The eyes popped out of their sockets (usually transl.: opened wide in surprise).
adj. orbital, -th, -th (to 1 and 3 values; special). Orbital space station.
New explanatory and derivational dictionary of the Russian language, T. F. Efremova.
orbit
The path along which a celestial body moves under the influence of the attraction of other celestial bodies.
The path of the spacecraft, satellite, etc. in a gravitational field celestial body.
Area, limits, scope, action of smth.
One of two depressions in the front of the skull that contain the eyes; eye socket.
Encyclopedic Dictionary, 1998
orbit
ORBIT (from lat. orbita - track, path) circle, scope, distribution; See also the orbit of a celestial body.
Orbit
"Orbit", the conventional name for space communication earth stations that form a single network on the territory of the USSR; transmit and receive for subsequent rebroadcasting monochrome and color programs of the Central Television (CT) via the Molniya communication satellites. The first 20 stations of the network began operating in 1967; by 1973 their number had increased to 40. With the creation of O. television centers in many remote areas of the country were able to broadcast 1 or 2 DH programs, in addition to programs received via cable and radio relay lines. Initially in Soviet system For space communications, Molniya-1 satellites were used, operating on decimeter waves. In 1972, the O.-2 stations also went into operation, operating on centimeter waves with Molniya-2 satellites. By May 1973, 11 O.-2 stations were receiving transmissions from Moscow (in 1974-75 it is planned to build 25 more stations). The current USSR space communications system is called Molniya-O. In addition to broadcasting television programs, this system also serves for two-way (duplex) exchange or unidirectional transmission of other types of information. Valid throughout the USSR. The duration of communication sessions through each Molniya satellite is ≈ 8≈10 hours per day.
Television signals emitted by the central earth stations of the "O." in the direction of the Molniya satellites, are received last, amplified and re-radiated to Earth. The received signals are sent via connecting lines to local television centers, from where they are broadcast on the air via one of the television channels assigned to the television center in the range of meter and decimeter waves. A single-span radio relay line is usually used as a connecting line (see Radio Relay Communication). For distances less than 1 km also apply cable lines with matching, corrective and antiphonal devices.
Station "O." are placed in typical round reinforced concrete structures that simultaneously serve as a support for the antenna system ( rice.). AT central hall The station concentrates all receiving equipment, equipment for pointing to the satellite and connecting lines. In adjacent rooms there is a ventilation and air conditioning system, antenna electric drive equipment, power supply equipment, etc. An antenna with a parabolic reflector with a diameter of 12 m is installed on a turntable and moves in azimuth and elevation with drives, accompanying the satellite with high accuracy (up to several angular minutes). Satellite tracking is controlled either automatically (via a television signal from a satellite or a software device) or manually. The antenna is able to work normally in the harsh climatic conditions of the Far North, Siberia, Far East and Central Asia without wind protection. The noise temperature of the antenna directed to the zenith does not exceed 10 K.
The frequency-modulated (FM) signal received by the antenna station is fed to the input device of the receiving equipment complex ≈ parametric amplifier. To obtain the greatest sensitivity, its first stages are cooled to the temperature of liquid nitrogen (77 K). From the output of the parametric amplifier, the signal is fed to the frequency converter and the intermediate frequency preamplifier (IFA) following it. Further, in a highly selective IF tuned to an intermediate frequency of 70 MHz, the main amplification of the received signals (up to 10 million times) is carried out while maintaining the linearity of the phase characteristic. Subsequent detection of FM signals is performed by a noise-immune demodulator ≈ synchronous phase detector. Since audio signals are transmitted using time multiplexing (see Communication lines multiplexing) in the same frequency band as video signals, the receiving complex includes equipment for separating image and sound signals. As part of the reception complex "O." also includes control equipment for operational testing of the performance of all its links and measuring its quality indicators. The equipment of the receiving complex has a 100% reserve, which allows in case emergency automatically switch from a working set of equipment to a backup one.
N. V. Talyzin.
Wikipedia
Orbit
Orbit- movement trajectory material point in a predetermined system of spatial coordinates for a configuration of the field of forces that act on it, given in these coordinates. The term was introduced by Johannes Kepler in the book New Astronomy (1609).
AT celestial mechanics is the trajectory of a celestial body in the gravitational field of another body with a significant larger mass(planets, comets, asteroids in the field of a star). In a rectangular coordinate system, the origin of which coincides with the center of mass, the trajectory may have the form conical section(circle, ellipse, parabola or hyperbola). In this case, its focus coincides with the center of mass of the system.
Orbita (Avila)
Examples of the use of the word orbit in the literature.
On the other hand, no one canceled the mission, and the aircraft carrier, this time without support ships, surfaced for orbit the planets are practically on the opposite side of it from the supposed position of the cruisers.
On the other hand, some black holes can be so huge that the accretion disks in their immediate vicinity are composed of intact stars that are, in effect, pushing each other along orbit and which are eventually completely absorbed - all this makes the regions in the immediate vicinity of the black hole unusually luminous and saturated with energetic radiation.
PRESENT: Aldebaran in Taurus, one of a pair of monstrous red stars whose sixteen planets raced in elliptical orbits around mutually rotating parents.
When we talk about Germanization plans, we mean plans to assimilate the occupied territories economically, politically, socially and culturally, pulling them into orbit German empire.
The bityug's satchel is stuffed with samples of dead uranium, the underground doctor of all sciences goes out of his way to shake the dormouse, and I hang around them indefinitely. orbit like a violet in a compost mixer.
Since Boltzmann occupied a stationary position relative to Multon and Dirac, the planets of the system moved along their own orbits with eternal constancy, there was no normal flight schedule.
And the ridiculous and awkward surroundings seemed to us temporary, and in this feeling we were not alone: in the footsteps of the article, some people came and went to us with slanderous ideas about recycling felted wool as a raw material for spraying, about building ocean yachts in an abandoned church and descend them into bypass channel or with a proposal to make a power source in Grisha's closet for the then launched on orbit rover.
The Noguchi equations were a set of variable field matrices that allowed the onboard AI to more accurately calculate the effects of the influence of close space curves on special Points located on orbit ships and install them with greater accuracy.
Think about how the development proceeded in the rays of their luminary - a double red giant, with anomalous days and nights, and the planet itself orbit, among natural fluctuations, with the most difficult growing conditions, in extreme heat and cold!
In principle, the differences between a galactic vortex, an atmospheric cyclone, and orbit There is no electron in an atom.
We're moving too fast to spin the normal orbit, so we'll fall outward and slow down.
The elder nodded his head in displeasure and asked El Ney to convey to El Rad the request of the Council to be present at the All-Planet Gathering, where the proposal of scientists for the return of Ichora to the former orbit.
Usually, the base of the celestial elevator was fixed at some suitable place on the planetary equator, and the other end, far beyond the synchroorbit, rested against an asteroid, previously brought to a specially calculated orbit.
You believed that hell was preparing swords, daggers, wheels, blades, burning sulfur, molten lead, ice water, cauldrons with grates, axes and oak, and awl for eye orbits, and tongs for holes in teeth, and claws for pulling out ribs, and chains for crushing bones, and what in hell are gnawing animals, dragging thorns, strangling rope, locusts, cross-torments, axes and chopping blocks?
A series of insane jump transitions, which exhausted the crew to a pulp, eventually threw them to the circumplanetary orbit Monaloi - a modest, long-forgotten little world in the densely populated regions of the center of the Galaxy, where, generally speaking, emerging from curved space is not practiced at all due to too large cluster stars and other material bodies.
