Volcanic chain (picture from space)
Mount Fuji in Japan (photo from space)
Olympic Village in Vancouver (photo from space)
Typhoon (picture from space)
If you have loved for a long time starry sky, then, of course, I saw a moving bright star. But in fact it was a satellite - a spacecraft that people specially launched into space orbit.
First artificial Earth satellite was launched by the Soviet Union in 1957. It was a huge event for the whole world, and this day is considered the beginning of the space age of mankind. Now about six thousand satellites revolve around the Earth, very different in weight and shape. They have learned a lot in 56 years.
For example, a communications satellite helps you watch TV shows. How does this happen? The satellite flies over the TV station. The transmission begins, and the TV station transmits the “picture” to the satellite, and he, as in a relay race, transmits it to another satellite, which is already flying over another place the globe. The second satellite broadcasts the image to the third one, which returns the “picture” back to Earth, to a television station located thousands of kilometers from the first one. Thus, TV programs can be watched simultaneously by residents of Moscow and Vladivostok. By the same principle, communication satellites help to conduct telephone conversations that connect computers.
satellites also watch the weather. Such a satellite flies high, storms, storms, thunderstorms, notices all atmospheric disturbances and transmits to Earth. And on Earth, weather forecasters process information and know what weather is expected.
Navigation satellites help ships navigate, because the GPS navigation system helps to determine, in any weather,
where they are. With the help of GPS-navigators built into mobile phones and car computers, you can determine your location, find the necessary houses and streets on the map.
There are also reconnaissance satellites. They take pictures of the Earth, and geologists determine from the photographs where rich deposits of oil, gas, and other minerals are located on our planet.
Research satellites help in scientific research. Astronomical - explore the planets of the solar system, galaxies and other space objects.
If you throw a stone, it will fly, gradually descending lower and lower until it hits the ground. If you throw a stone harder, it will fall further. As you know, the earth is round. Is it possible to throw a rock so hard that it circles the earth? It turns out you can. You just need more speed - almost eight kilometers per second - that's thirty times faster than an airplane. And this must be done outside the atmosphere, otherwise the friction against the air will greatly interfere. But, if you manage to do this, the stone will fly around the Earth by itself without stopping.
Satellites are launched on rockets that fly upward from the Earth's surface. Having risen, the rocket turns and begins acceleration in a lateral orbit. It is the lateral movement that keeps satellites from falling to Earth. They fly around her, like our invented stone!
On the outside of the Sputnik, four whip antennas were transmitting at shortwave frequencies above and below the current standard (27 MHz). Tracking stations on Earth picked up a radio signal and confirmed that the tiny satellite had survived the launch and was successfully on course around our planet. A month later Soviet Union launched Sputnik 2 into orbit. Inside the capsule was the dog Laika.
In December 1957, desperate to keep up with their Cold War adversaries, American scientists attempted to put a satellite into orbit along with the planet Vanguard. Unfortunately, the rocket crashed and burned down at the takeoff stage. Shortly thereafter, on January 31, 1958, the US repeated the USSR's success by adopting Wernher von Braun's plan to launch the Explorer-1 satellite with the U.S. redstone. Explorer 1 carried instruments to detect cosmic rays and found, in an experiment by James Van Allen of the University of Iowa, that there were far fewer cosmic rays than expected. This led to the discovery of two toroidal zones (eventually named after Van Allen) filled with charged particles trapped in the Earth's magnetic field.
Encouraged by these successes, some companies started developing and launching satellites in the 1960s. One of them was Hughes Aircraft along with star engineer Harold Rosen. Rosen led the team that brought Clarke's idea to fruition - a communications satellite placed in Earth's orbit in such a way that it could reflect radio waves from one place to another. In 1961, NASA awarded Hughes a contract to build a series of Syncom (synchronous communications) satellites. In July 1963, Rosen and his colleagues saw Syncom-2 take off into space and enter a rough geosynchronous orbit. President Kennedy used new system to speak with the Prime Minister of Nigeria in Africa. Syncom-3 soon took off, which could actually broadcast a television signal.
The era of satellites has begun.
Technically, a satellite is any object that orbits a planet or smaller celestial body. Astronomers classify the moons as natural satellites, and over the years they have compiled a list of hundreds of such objects orbiting the planets and dwarf planets of our solar system. For example, they counted 67 moons of Jupiter. And so far.
Man-made objects such as Sputnik and Explorer can also be classified as satellites, since they, like the moons, revolve around the planet. Unfortunately, human activity has led to the fact that a huge amount of garbage appeared in the Earth's orbit. All these pieces and debris behave like large rockets - revolve around the planet at high speed in a circular or elliptical path. In a strict interpretation of the definition, each such object can be defined as a satellite. But astronomers, as a rule, consider as satellites those objects that perform a useful function. Fragments of metal and other trash fall into the category of orbital debris.
Orbital debris comes from many sources:
NASA launched a special satellite called LDEF to study the long-term effects of space debris impacts. Over the course of six years, the satellite's instruments recorded about 20,000 impacts, some caused by micrometeorites and others by orbital debris. NASA scientists continue to analyze LDEF data. But in Japan there is already a giant network for catching space debris.
Satellites are different forms and sizes and perform many different functions, but all, in principle, are similar. All of them have a metal or composite frame and a body that English-speaking engineers call a bus, and Russians call a space platform. The space platform brings everything together and provides enough measures to ensure that the instruments survive the launch.
All satellites have a power source (usually solar panels) and batteries. Solar arrays allow batteries to be charged. The latest satellites also include fuel cells. Satellite energy is very expensive and extremely limited. Nuclear power cells are commonly used to send space probes to other planets.
All satellites have an onboard computer to control and monitor various systems. All have a radio and an antenna. At a minimum, most satellites have a radio transmitter and receiver so that the ground crew can query and monitor the satellite's status. Many satellites allow a lot of different things, from changing the orbit to reprogramming the computer system.
As you might expect, putting all these systems together is not an easy task. It takes years. It all starts with defining the purpose of the mission. Determining its parameters allows engineers to assemble the right tools and install them in right order. Once the specification (and budget) is approved, the assembly of the satellite begins. It takes place in a clean room, in a sterile environment that maintains the correct temperature and humidity and protects the satellite during development and assembly.
Artificial satellites are usually made to order. Some companies have developed modular satellites, that is, structures that can be assembled to allow additional elements to be installed according to the specification. For example, the Boeing 601 satellites had two basic modules - a chassis for transporting the propulsion subsystem, electronics and batteries; and a set of honeycomb shelves for equipment storage. This modularity allows engineers to assemble satellites not from scratch, but from a blank.
Today, all satellites are launched into orbit on a rocket. Many transport them in the cargo department.
In most satellite launches, the rocket is fired straight up, which allows it to pass through the thick atmosphere faster and minimize fuel consumption. After the missile takes off, the missile's control mechanism uses the inertial guidance system to calculate the necessary adjustments to the missile's nozzle to achieve the desired tilt.
After the rocket enters the rarefied air, at a height of about 193 kilometers, the navigation system releases small rackets, which is enough to flip the rocket to a horizontal position. After that, the satellite is released. Small rockets are fired again and provide a difference in distance between the rocket and the satellite.
The rocket must reach a speed of 40,320 kilometers per hour to completely escape Earth's gravity and fly into space. Space velocity is much greater than what a satellite needs in orbit. They do not escape the earth's gravity, but are in a state of balance. Orbital speed is the speed required to maintain a balance between the gravitational pull and the inertial motion of the satellite. This is approximately 27,359 kilometers per hour at an altitude of 242 kilometers. Without gravity, inertia would carry the satellite into space. Even with gravity, if a satellite moves too fast, it will be blown into space. If the satellite moves too slowly, gravity will pull it back towards Earth.
The orbital speed of a satellite depends on its height above the Earth. The closer to Earth, the faster the speed. At an altitude of 200 kilometers, the orbital speed is 27,400 kilometers per hour. To maintain an orbit at an altitude of 35,786 kilometers, the satellite must rotate at a speed of 11,300 kilometers per hour. This orbital speed allows the satellite to make one pass every 24 hours. Since the Earth also rotates 24 hours, the satellite at an altitude of 35,786 kilometers is in a fixed position relative to the Earth's surface. This position is called geostationary. The geostationary orbit is ideal for meteorological and communications satellites.
In general, the higher the orbit, the longer the satellite can stay in it. At low altitude, the satellite is in the earth's atmosphere, which creates drag. At high altitude, there is practically no resistance, and a satellite, like the moon, can be in orbit for centuries.
On earth, all satellites look similar - shiny boxes or cylinders decorated with wings made of solar panels. But in space, these clumsy machines behave very differently depending on their flight path, altitude, and orientation. As a result, the classification of satellites becomes a complex matter. One approach is to determine the orbit of the vehicle relative to the planet (usually the Earth). Recall that there are two main orbits: circular and elliptical. Some satellites start in an ellipse and then go into a circular orbit. Others move in an elliptical path known as the "Lightning" orbit. These objects typically circle north-south across the Earth's poles and complete a full circle in 12 hours.
Polar-orbiting satellites also pass through the poles with each revolution, although their orbits are less elliptical. Polar orbits remain fixed in space while the Earth rotates. As a result, most of the Earth passes under the satellite in polar orbit. Since polar orbits give excellent coverage of the planet, they are used for mapping and photography. Forecasters also rely on a global network of polar satellites that circle our globe in 12 hours.
You can also classify satellites by their height above the earth's surface. Based on this scheme, there are three categories:
Finally, one can think of satellites in the sense of where they are "looking for". Most of the objects sent into space over the past few decades are looking at the Earth. These satellites have cameras and equipment that can see our world in different wavelengths of light, allowing us to enjoy a breathtaking spectacle in our planet's ultraviolet and infrared tones. Fewer satellites turn their eyes to space, where they observe stars, planets and galaxies, and also scan for objects like asteroids and comets that could collide with the Earth.
Until recently, satellites have remained exotic and top-secret devices used primarily for military purposes for navigation and espionage. Now they have become an integral part of our Everyday life. Thanks to them, we will know the weather forecast (although weather forecasters, oh, how often they are wrong). We watch TV and work with the Internet also thanks to satellites. GPS in our cars and smartphones allows us to get to the right place. Is it worth talking about the invaluable contribution of the Hubble telescope and the work of astronauts on the ISS?
However, there are real heroes of the orbit. Let's get to know them.
After Sputnik and Explorer, satellites have gotten bigger and more complex. Take, for example, TerreStar-1, a commercial satellite that was supposed to provide mobile data transmission in North America for smartphones and similar devices. Launched in 2009, TerreStar-1 weighed 6910 kilograms. And when fully deployed, it revealed an 18-meter antenna and massive solar arrays with a wingspan of 32 meters.
Building such a complex machine requires a lot of resources, so historically only government departments and corporations with deep pockets could get into the satellite business. Most of the cost of a satellite lies in the equipment - transponders, computers and cameras. A typical weather satellite costs about $290 million. The spy satellite will cost $100 million more. Add to this the cost of maintaining and repairing satellites. Companies must pay for satellite bandwidth in the same way that phone owners pay for cellular communications. It sometimes costs more than 1.5 million dollars a year.
Other an important factor is the startup cost. Launching a single satellite into space can cost anywhere from $10 million to $400 million, depending on the craft. The Pegasus XL rocket can lift 443 kilograms into low Earth orbit for $13.5 million. Launching a heavy satellite will require more lift. An Ariane 5G rocket can launch an 18,000-kilogram satellite into low orbit for $165 million.
Despite the costs and risks associated with building, launching and operating satellites, some companies have managed to build entire businesses around it. For example, Boeing. In 2012, the company delivered about 10 satellites into space and received orders for more than seven years, generating nearly $32 billion in revenue.
Almost fifty years after the launch of Sputnik, satellites, like budgets, are growing and getting stronger. The US, for example, has spent almost $200 billion since the start of the military satellite program and now, in spite of all this, has a fleet of aging vehicles waiting to be replaced. Many experts fear that the construction and deployment of large satellites simply cannot exist on taxpayer money. The solution that could turn everything upside down remains private companies like SpaceX and others that clearly won't be caught in bureaucratic stagnation like NASA, NRO and NOAA.
Another solution is to reduce the size and complexity of the satellites. Scientists at Caltech and Stanford University have been working since 1999 on a new type of CubeSat satellite, based on building blocks with a 10-centimeter edge. Each cube contains ready-made components and can be combined with other cubes to increase efficiency and reduce workload. By standardizing designs and reducing the cost of building each satellite from scratch, a single CubeSat can cost as little as $100,000.
In April 2013, NASA decided to test this simple principle and three CubeSats based on commercial smartphones. The goal was to put the microsatellites into orbit for a short time and take some pictures with the phones. The agency now plans to deploy an extensive network of such satellites.
Whether big or small, the satellites of the future must be able to communicate effectively with ground stations. Historically, NASA has relied on RF communications, but RF has reached its limit as demand for more power has arisen. To overcome this hurdle, NASA scientists are developing a two-way communication system based on lasers instead of radio waves. On October 18, 2013, scientists first launched a laser beam to transmit data from the Moon to Earth (at a distance of 384,633 kilometers) and received a record transfer rate of 622 megabits per second.
Soviet artificial earth satellites. The first artificial satellite of the Earth.
Artificial Earth Satellites(AES), spacecraft launched into orbit around the Earth and designed to solve scientific and applied problems. The launch of the first satellite, which became the first artificial celestial body created by man, was carried out in the USSR on October 4 and was the result of achievements in the field of rocketry, electronics, automatic control, computer technology, celestial mechanics, and other sections of science and technology. With the help of this satellite, the density of the upper atmosphere was measured for the first time (by changes in its orbit), the features of the propagation of radio signals in the ionosphere were studied, theoretical calculations and the main technical solutions associated with launching a satellite into orbit were verified. On February 1, the first American satellite "Explorer-1" was launched into orbit, and a little later, independent launches of satellites were made by other countries: November 26, 1965 - France (satellite "A-1"), November 29, 1967 - Australia ("VRESAT-1 ”), February 11, 1970 - Japan (“Osumi”), April 24, 1970 - China (“China-1”), October 28, 1971 - Great Britain (“Prospero”). Some satellites made in Canada, France, Italy, Great Britain, and other countries have been launched (since 1962) using American launch vehicles. In the practice of space research, international cooperation has become widespread. Thus, a number of satellites have been launched within the framework of scientific and technical cooperation between the socialist countries. The first of these, Interkosmos-1, was launched into orbit on October 14, 1969. By 1973, more than 1,300 satellites of various types had been launched, including about 600 Soviet and over 700 American and other countries, including manned spacecraft-satellites and crewed orbital stations.
Soviet artificial earth satellites. "Electron".
In accordance with international agreement, a spacecraft is called a satellite if it has made at least one revolution around the Earth. Otherwise, it is considered to be a rocket probe that made measurements along a ballistic trajectory and is not registered as a satellite. Depending on the tasks solved with the help of satellites, they are divided into research and applied. If radio transmitters are installed on the satellite, this or that measuring equipment, flash lamps for giving light signals, etc., it is called active. Passive satellites are usually intended for observations from the earth's surface when solving certain scientific problems (these satellites include balloon satellites, reaching a diameter of several tens of m). Research satellites are used for Earth exploration, celestial bodies, outer space. These include, in particular, geophysical satellites, geodetic satellites, orbital astronomical observatories, etc. Applied satellites are communication satellites, meteorological satellites, satellites for the study of terrestrial resources, navigation satellites, satellites for technical purposes (for studying the impact of space conditions on materials, for testing and testing on-board systems), etc. AES designed for human flight are called manned spacecraft-satellites. Satellites in an equatorial orbit lying near the plane of the equator are called equatorial, satellites in a polar (or subpolar) orbit passing near the Earth's poles are called polar. AES launched into a circular equatorial orbit, remote at 35860 km from the surface of the Earth, and moving in a direction coinciding with the direction of rotation of the Earth, "hang" motionless over one point on the earth's surface; such satellites are called stationary. The last stages of launch vehicles, nose fairings and some other parts that are separated from satellites during launch into orbits are secondary orbital objects; they are not usually referred to as satellites, although they circulate in near-Earth orbits and in some cases serve as objects of observation for scientific purposes.
Foreign artificial satellites of the Earth. "Explorer-25".
Foreign artificial satellites of the Earth. Diadem-1.
In accordance with the international system for registering space objects (satellites, space probes, etc.) within the framework of the international organization COSPAR in 1957-1962, space objects were designated by the launch year with the addition of a Greek alphabet letter corresponding to the serial number of the launch in a given year, and an Arabic numeral - the number an orbiting object depending on its brightness or degree of scientific significance. So, 1957a2 is the designation of the first Soviet satellite, launched in 1957; 1957a1 - designation for the last stage of the launch vehicle of this satellite (the launch vehicle was brighter). Since the number of launches increased, starting from January 1, 1963, space objects began to be designated by the year of launch, the sequence number of the launch in a given year, and capital letter Latin alphabet (sometimes also replaced by an ordinal number). So, the Interkosmos-1 satellite has the designation: 1969 88A or 1969 088 01. In national space research programs, the satellite series often also have their own names: Cosmos (USSR), Explorer (USA), Diadem (France ), etc. Abroad, the word "satellite" until 1969 was used only in relation to Soviet satellites. In 1968-69, when preparing an international multilingual cosmonautical dictionary, an agreement was reached according to which the term "satellite" is applied to satellites launched in any country.
Soviet artificial earth satellites. "Proton-4".
In accordance with the variety of scientific and applied problems solved with the help of satellites, satellites can have various sizes, mass, structural diagrams, composition of on-board equipment. For example, the mass of the smallest satellite (from the EPC series) is only 0.7 kg; Soviet satellite "Proton-4" had a mass of about 17 t. The mass of the Salyut orbital station with the Soyuz spacecraft docked to it was over 25 t. The largest payload mass put into orbit by a satellite was about 135 t(US spacecraft "Apollo" with the last stage of the launch vehicle). There are automatic satellites (research and applied), on which the operation of all instruments and systems is controlled by commands coming either from the Earth or from an onboard software device, manned spacecraft-satellites and orbital stations with a crew.
To solve some scientific and applied problems, it is necessary that the satellite be oriented in space in a certain way, and the type of orientation is determined mainly by the purpose of the satellite or the features of the equipment installed on it. So, the orbital orientation, in which one of the axes is constantly directed along the vertical, have satellites designed to observe objects on the surface and in the Earth's atmosphere; AES for astronomical research are guided by celestial objects: stars, sun. At the command from the Earth or according to a given program, the orientation can change. In some cases, not the entire satellite is oriented, but only its individual elements, for example, highly directional antennas - to ground points, solar panels - to the Sun. In order for the direction of a certain axis of the satellite to remain unchanged in space, it is told to rotate around this axis. For orientation, gravitational, aerodynamic, magnetic systems are also used - the so-called passive orientation systems, and systems equipped with reactive or inertial controls (usually on complex satellites and spacecraft) - active orientation systems. AES with jet engines for maneuvering, trajectory correction or descent from orbit are equipped with motion control systems, integral part which is the orientation system.
Foreign artificial satellites of the Earth. "OSO-1".
The onboard equipment of most satellites is powered by solar batteries, the panels of which are oriented perpendicular to the direction of the sun's rays or arranged so that some of them are illuminated by the Sun at any position relative to the satellite (the so-called omnidirectional solar batteries). Solar panels provide long work on-board equipment (up to several years). AES, designed for limited periods of operation (up to 2-3 weeks), use electrochemical current sources - batteries, fuel cells. Some satellites have isotope generators on board. electrical energy. The thermal regime of satellites, necessary for the operation of their onboard equipment, is maintained by thermal control systems.
In satellites, which are distinguished by a significant heat release of equipment, and spacecraft, systems with a liquid heat transfer circuit are used; on satellites with low heat release, equipment in some cases is limited to passive means of thermal control (selection of an external surface with a suitable optical coefficient, thermal insulation of individual elements).
Foreign artificial satellites of the Earth. "Oscar-3".
The transfer of scientific and other information from satellites to Earth is carried out using radio telemetry systems (often with on-board storage devices for recording information during periods of satellite flight outside the radio visibility zones of ground stations).
Manned satellites and some automatic satellites have descent vehicles for returning to Earth the crew, individual instruments, films, and experimental animals.
Foreign artificial satellites of the Earth. "Gemini".
AES are launched into orbits with the help of automatic guided multi-stage launch vehicles, which move from launch to a certain calculated point in space thanks to the thrust developed by jet engines. This path, called the trajectory of launching an artificial satellite into orbit, or the active section of the rocket, usually ranges from several hundred to two to three thousand kilometers. km. The rocket starts moving vertically upwards and passes through the densest layers earth's atmosphere at a relatively low speed (which reduces energy costs to overcome atmospheric resistance). When lifting, the rocket gradually turns around, and the direction of its movement becomes close to horizontal. On this almost horizontal segment, the thrust force of the rocket is spent not on overcoming the braking effect of the Earth's gravity forces and atmospheric resistance, but mainly on increasing the speed. After the rocket reaches the design speed (in magnitude and direction) at the end of the active section, the operation of jet engines stops; this is the so-called point of launching the satellite into orbit. The launched spacecraft, which carries the last stage of the rocket, automatically separates from it and begins its movement in some orbit relative to the Earth, becoming an artificial celestial body. Its movement is subject to passive forces (the attraction of the Earth, as well as the Moon, the Sun and other planets, the resistance of the earth's atmosphere, etc.) and active (controlling) forces, if special jet engines are installed on board the spacecraft. The type of the initial orbit of the satellite relative to the Earth depends entirely on its position and speed at the end of the active segment of the movement (at the moment the satellite enters the orbit) and is mathematically calculated using the methods of celestial mechanics. If this speed is equal to or exceeds (but not more than 1.4 times) the first escape velocity (about 8 km/sec near the surface of the Earth), and its direction does not deviate strongly from the horizontal, then the spacecraft enters the orbit of the Earth’s satellite. The point of entry of the satellite into orbit in this case is located near the perigee of the orbit. Orbit entry is also possible at other points of the orbit, for example, near the apogee, but since in this case the satellite orbit is located below the launch point, the launch point itself should be located high enough, while the speed at the end of the active segment should be somewhat less than circular.
In the first approximation, the satellite orbit is an ellipse with a focus at the center of the Earth (in a particular case, a circle), which maintains a constant position in space. Motion along such an orbit is called unperturbed and corresponds to the assumptions that the Earth attracts according to Newton's law as a ball with a spherical density distribution and that only the Earth's gravity acts on the satellite.
Factors such as the resistance of the earth's atmosphere, the compression of the earth, pressure solar radiation, the attraction of the Moon and the Sun, are the cause of deviations from the unperturbed motion. The study of these deviations makes it possible to obtain new data on the properties of the earth's atmosphere, on the earth's gravitational field. Due to atmospheric resistance, satellites moving in orbits with a perigee at an altitude of several hundred km, gradually decrease and, falling into relatively dense layers of the atmosphere at a height of 120-130 km and below, collapse and burn; they thus have a limited lifespan. So, for example, the first Soviet satellite was at the moment of entering the orbit at an altitude of about 228 km above the Earth's surface and had an almost horizontal velocity of about 7.97 km/sec. The semi-major axis of its elliptical orbit (i.e., the average distance from the center of the Earth) was about 6950 km, circulation period 96.17 min, and the least and most distant points of the orbit (perigee and apogee) were located at altitudes of about 228 and 947 km respectively. The satellite existed until January 4, 1958, when, due to disturbances in its orbit, it entered the dense layers of the atmosphere.
The orbit into which the satellite is launched immediately after the boost phase of the launch vehicle is sometimes only intermediate. In this case, there are jet engines on board the satellite, which turn on at certain moments for a short time on command from the Earth, giving the satellite an additional speed. As a result, the satellite moves to another orbit. Automatic interplanetary stations are usually launched first into the orbit of an Earth satellite, and then transferred directly to the flight path to the Moon or planets.
Foreign artificial satellites of the Earth. "Transit".
Control of the movement of satellites and secondary orbital objects is carried out by observing them from special ground stations. Based on the results of such observations, the elements of satellite orbits are refined and ephemeris is calculated for upcoming observations, including those for solving various scientific and applied problems. According to the observation equipment used, satellites are divided into optical, radio engineering, laser; according to their ultimate goal - to positional (determining directions on satellites) and range-finding observations, measurements of angular and spatial velocity.
The simplest positional observations are visual (optical), performed with the help of visual optical instruments and allowing to determine the celestial coordinates of satellites with an accuracy of several minutes of arc. To solve scientific problems, photographic observations are carried out using satellite cameras, providing accuracy of determinations up to 1-2¢¢ in position and 0.001 sec by time. Optical observations are possible only when the satellite is illuminated by the sun's rays (the exception is geodetic satellites equipped with pulsed light sources; they can be observed even when in the Earth's shadow), the sky above the station is sufficiently dark, and the weather is favorable for observations. These conditions significantly limit the possibility of optical observations. Less dependent on such conditions are the radio engineering methods of observing satellites, which are the main methods of observing satellites during the operation of special radio systems installed on them. Such observations consist in the reception and analysis of radio signals, which are either generated by the onboard radio transmitters of the satellite, or sent from the Earth and relayed by the satellite. Comparison of the phases of signals received on several (minimum three) spaced antennas allows you to determine the position of the satellite on the celestial sphere. The accuracy of such observations is about 3¢ in position and about 0.001 sec by time. Measurement of the Doppler frequency shift (see Doppler effect) of radio signals makes it possible to determine the relative speed of the satellite, the minimum distance to it during the observed passage, and the time when the satellite was at this distance; Observations performed simultaneously from three points make it possible to calculate the angular velocities of the satellite.
Range-finding observations are carried out by measuring the time interval between the sending of a radio signal from the Earth and its reception after its retransmission by an onboard satellite transponder. The most accurate measurements of distances to satellites are provided by laser rangefinders (accuracy up to 1-2 m and higher). Radar systems are used for radio technical observations of passive space objects.
Soviet artificial earth satellites. Satellite of the Kosmos series is an ionospheric laboratory.
The equipment installed on board the satellite, as well as satellite observations from ground stations, make it possible to carry out various geophysical, astronomical, geodetic, and other studies. The orbits of such satellites are varied - from almost circular at an altitude of 200-300 km to elongated elliptical with apogee height up to 500 thousand meters. km. Research satellites include the first Soviet satellites, Soviet satellites of the Elektron, Proton, Kosmos series, American satellites of the Avangard, Explorer, OSO, OSO, OAO series (orbital geophysical , solar, astronomical observatories); the English satellite "Ariel", the French satellite "Diadem" and others. Research satellites account for about half of all launched satellites.
With the help of scientific instruments installed on satellites, the neutral and ionic composition of the upper atmosphere, its pressure and temperature, as well as changes in these parameters are studied. The electron concentration in the ionosphere and its variations are studied both with the help of onboard equipment and by observing the passage of radio signals from onboard radio beacons through the ionosphere. With the help of ionosondes, the structure of the upper part of the ionosphere (above the main maximum of the electron density) and the changes in the electron density depending on the geomagnetic latitude, time of day, etc. have been studied in detail. All the results of atmospheric studies obtained using satellites are important and reliable experimental material for understanding the mechanisms of atmospheric processes and to solve such practical issues as radio communication forecast, forecast of the state of the upper atmosphere, etc.
With the help of satellites, the radiation belts of the Earth have been discovered and are being studied. Along with space probes, satellites made it possible to study the structure of the Earth’s magnetosphere and the nature of the solar wind flow around it, as well as the characteristics of the solar wind itself (flux density and particle energy, the magnitude and nature of the “frozen-in” magnetic field) and other solar radiation inaccessible to ground observations - ultraviolet and X-ray, which is of great interest from the point of view of understanding solar-terrestrial relations. Valuable data for scientific research is also provided by some applied satellites. Thus, the results of observations carried out on meteorological satellites are widely used for various geophysical studies.
The results of satellite observations make it possible to determine with high accuracy the perturbations of satellite orbits, changes in the density of the upper atmosphere (due to various manifestations solar activity), the laws of atmospheric circulation, the structure of the Earth's gravitational field, etc. Specially organized positional and ranging synchronous observations of satellites (simultaneously from several stations) using satellite geodesy methods make it possible to geodetic referencing points thousands of km from each other, to study the movement of the continents, etc.
Foreign artificial satellites of the Earth. Syncom-3.
Applied satellites include satellites launched to solve various technical, economic, military tasks.
Communication satellites serve to provide television broadcasts, radiotelephone, telegraph and other types of communication between ground stations located at distances of up to 10-15 thousand km from each other. km. The onboard radio equipment of such satellites receives signals from ground radio stations, amplifies them and retransmits them to other ground radio stations. Communication satellites are launched into high orbits (up to 40,000 km). This type of satellite includes the Soviet satellite "Lightning ", the American satellite "Sincom", the satellite "Intelsat", etc. Communication satellites launched into stationary orbits are constantly located above certain areas of the earth's surface.
Soviet artificial earth satellites. "Meteor".
Foreign artificial satellites of the Earth. Tyros.
Meteorological satellites are designed for regular transmission to ground stations of television images of the Earth's cloudy, snow and ice cover, information about thermal radiation earth's surface and clouds, etc. AES of this type are launched into orbits close to circular, with a height of 500-600 km up to 1200-1500 km; the swath from them reaches 2-3 thousand km. km. Meteorological satellites include some Soviet satellites of the Kosmos series, satellites Meteor, American satellites Tiros, ESSA, Nimbus. Experiments are being carried out on global meteorological observations from altitudes reaching 40 thousand meters. km(Soviet satellite "Molniya-1", American satellite "ATS").
Exceptionally promising from the point of view of application in the national economy are satellites for the study of the natural resources of the Earth. Along with meteorological, oceanographic and hydrological observations, such satellites make it possible to obtain operational information necessary for geology, Agriculture, fisheries, forestry, environmental pollution control. The results obtained with the help of satellites and manned spacecraft, on the one hand, and control measurements from balloons and aircraft, on the other, show the prospects for the development of this area of research.
Navigation satellites, the operation of which is supported by a special ground-based support system, serve to navigate sea ships, including submarines. The ship, receiving radio signals and determining its position relative to the satellite, whose coordinates in orbit are known with high accuracy at every moment, establishes its position. An example of navigation satellites are the American satellites "Transit", "Navsat".
Soviet artificial earth satellites. "Salute".
Manned satellites and manned orbital stations are the most complex and advanced satellites. They, as a rule, are designed to solve a wide range of tasks, primarily for conducting complex scientific research, testing space technology, studying the natural resources of the Earth, etc. The first launch of a manned satellite was carried out on April 12, 1961: on a Soviet satellite Vostok, pilot-cosmonaut Yu. A. Gagarin flew around the Earth in an orbit with an apogee altitude of 327 km. February 20, 1962 went into orbit the first American spacecraft with astronaut J. Glenn on board. A new step in the exploration of outer space with the help of manned satellites was the flight of the Soviet Salyut orbital station, Space Speeds, Spacecraft.
Literature:
N. P. Erpylev, M. T. Kroshkin, Yu. A. Ryabov, E. F. Ryazanov.
This article or section uses textYudakova Daria
At present, more and more relevance acquires the development of the space industry, as artificial Earth satellites help to study the Earth, rationally exploit natural resources, protect environment. Thousands of scientists, engineers and technicians are already today looking for new solutions, laying the foundations of spacecraft, which in a few years will replace those already plowing the universe.
municipal budgetary educational institution
the city of Rostov-on-Don
"School No. 60 named after the Fifth Guards Don Cossack Cavalry Red Banner Budapest Corps"
(MBOU "School No. 60")
__________________________________________________________________
ESSAY
“Projects of national cosmonautics. Artificial satellites of the Earth»
Performed:
student 4 "B" class
Yudakova Daria Teacher:
Khramtsova Elena Anatolievna
Rostov-on-Don
2016
Introduction ………………………………………………………..……………..3
Conclusion………………………………………………………………10-11
References………………………………………………………….11
Application………………………………………………………………12-13
Introduction
“The first great step of mankind is to fly out of the atmosphere and become a satellite of the Earth. The rest is relatively easy, up to the distance from our solar system.
K. D. Tsiolkovsky
Perhaps already many thousands of years ago, looking at the night sky, a person dreamed of flying to the stars. Myriads of twinkling night luminaries forced him to be carried away by thought to the boundless distances of the Universe, awakened his imagination, forced him to think about the secrets of the universe. Centuries passed, man gained more and more power over nature, but the dream of flying to the stars remained as unrealizable as thousands of years ago.
The great honor of opening the way to other worlds for people fell to our compatriot K. E. Tsiolkovsky.Tsiolkovsky's ideas were universally recognized as early as the 1920s.
In 2016 we are celebrating the 70th anniversary of the domestic space industry -On May 13, 1946, I. V. Stalin signed a decree on the creation in the USSR of the rocket branch of science and industry.
At present, more and more relevance acquires the development of the space industry, asartificial Earth satellites help to study the Earth, rationally exploitNatural resources , protect the environment.Thousands of scientists, engineers and technicians are already today looking for new solutions, laying the foundations of spacecraft, which in a few years will replace those already plowing the universe.
Target project: to determine what artificial earth satellites are, to study the scope of their use.
Tasks: to study the material on this issue, to make a model of the first artificial satellite.
1.1 Legends and myths about space
The legends and myths of all peoples are full of stories about the flight to the Moon, the Sun and the stars. The means for such flights, offered by folk fantasy, were primitive: a chariot drawn by eagles, wings attached to human hands.
In the 17th century, the fantastic story of the French writer Cyrano de Bergerac about the flight to the moon appeared. The heroes of this story reached the moon in an iron strip, over which he constantly threw a strong magnet. Attracted to it, the strip rose higher and higher above the Earth until it reached the Moon. Jules Verne's heroes set off from the cannon to the moon. Famous English writer Herbert Wales described a fantastic journey to the moon in a projectile, the body of which was made of a material not subject to gravity.
Various means have been proposed for the implementation of space flight. Science fiction writers also mentioned rockets. However, these missiles were technically an unsound dream. Scientists for many centuries have not named the only means at the disposal of man, with the help of which it is possible to overcome the mighty force of the earth's gravity and be carried away into interplanetary space.
May 13, 1946 . Stalin signed a decree on the creation in the USSR of the rocket branch of science and industry. In August, S.P. Korolev was appointed chief designer of long-range ballistic missiles.
But back in 1931, the Jet Propulsion Study Group was created in the USSR, which was engaged in the design of rockets. Zander, Tikhonravov, Pobedonostsev, Korolev worked in this group. In 1933, on the basis of this group, the Jet Institute was organized, which continued work on the creation and improvement of rockets.
Launch goals: verification of calculations and main technical solutions adopted for the launch; ionospheric studies of the passage of radio waves emitted by satellite transmitters; experimental determination of density upper layers atmosphere for satellite deceleration;
study of the operating conditions of the equipment.
Despite the fact that the satellite completely lacked any scientific equipment, the study of the nature of the radio signal and optical observations of the orbit made it possible to obtain important scientific data.
1.3 First artificial earth satellite
To implement such a complex task as launching an artificial satellite of the Earth, it was necessary to combine huge scientific forces and technical means. This first step into space was very difficult.
It is no coincidence that K. E. Tsiolkovsky said that in the exploration of outer space “The first great step of mankind is to fly out of the atmosphere and become a satellite of the Earth. The rest is relatively easy, up to the distance from our solar system.
Sputnik-1 is the first artificial satellite of the Earth, the first spacecraft, launched into orbit in the USSR on October 4, 1957.
The code designation of the satellite is PS-1 (The Simplest Sputnik-1). The launch was carried out from the 5th Tyura-Tam research site of the USSR Ministry of Defense (later this place was called the Baikonur Cosmodrome) on a Sputnik launch vehicle (R-7).
Scientists M. V. Keldysh, M. K. Tikhonravov, N. S. Lidorenko and many others worked on the creation of an artificial satellite of the Earth, headed by the founder of practical astronautics S. P. Korolev.
The body of the satellite consisted of two hemispheres with a diameter of 58 cm made of aluminum alloy with docking frames interconnected by 36 bolts. The tightness of the joint was provided by a rubber gasket. Two antennas were located in the upper half-shell, each of two pins 2.4 m and 2.9 m each. Since the satellite was not oriented, the four-antenna system gave uniform radiation in all directions.
A block of electrochemical sources was placed inside the hermetic case; radio transmitting device; fan; thermal relay and air duct of the thermal control system; switching device of onboard electroautomatics; temperature and pressure sensors; onboard cable network. Mass of the first satellite: 83.6 kg.
The date of the launch of the first artificial satellite of the Earth is considered the beginning of the space age of mankind, and in Russia it is celebrated as a memorable day for the Space Forces.
GLOBAL NAVIGATIONAL SATELLITE S System (GLONASS) - Soviet and Russian satellite system, which began to be developed in 1976. Officially put into operation in 1993. In total, from 1982 to 1998, 74 spacecraft were launched into orbit, at the prices of 1997, $ 2.5 billion was spent on deployment. By 1995, the constellation was deployed almost to the full complement - up to 24 satellites.
However, further, due to weak funding and the short service life of satellites, their number began to decline rapidly. By 2001, only 6 active spacecraft remained. In August 2001, the federal target program "Global Navigation System" was adopted, according to which coverage of Russia should be provided by 2008, and global coverage in 2010. This program was implemented with minor amendments. On September 2, 2010, the GLONASS constellation consisted of 26 satellites.
The FTP "Maintenance, development and use of the GLONASS system for 2012-2020" provides for the manufacture of 13 Glonass-M with a service life of 7 years and 22 Glonass-K with a service life of 10 years.
In addition to the Russian GLONASS, only one global navigation system is currently operating: the American GPS. For its operation, like the Russian GLONASS, it requires 24 working satellites.
Several more satellite navigation systems are slowly deployed on the planet:
The Chinese Beidou system already has 16 satellites out of about 30-35. Already functioning as a regional navigation system, by 2020 it is planned to become global;
The European Galileo system, whose satellites are launched using Soyuz-STB rockets from the cosmodrome in Kourou. The first types of services should be provided in 2014;
The Indian IRNSS, out of 7 satellites, will cover only India itself and adjacent territories. Completion of works - 2015.
Differential correction systems stand apart, which can significantly increase positioning accuracy. Such systems may include both ground measuring stations and signal repeaters on satellites (usually in geostationary and geosynchronous orbits). For GLONASS, the role of such a system is played byRussian System of Differential Correction and Monitoring (SDCM) .
The first Russian smartphones with GLONASS support caused a hail of well-founded criticism due to high price and modest specifications. Skeptics expressed the opinion that the path to the consumer market was closed for GLONASS. However, today the Russian satellite system is used by the world's leading brands: Apple, BlackBerry, HP, HTC, Nokia, Samsung, Sharp, Sony Ericsson and others.
GLONASS support is often not displayed in the interface in any way mobile devices, the chipset automatically selects the most suitable satellites. For example, domestic chipML8088s allows you to determine the location by satellites GPS, GLONASS and GALILEO.
1.5 Solutions based on GLONASS technologies
Solutions based on GLONASS technologies are being actively introduced into our lives. Modern systems monitoring and control of transport can reduce the cost of transporting people and goods, save fuel, optimize logistics, reduce emissions into the atmosphere - all together this gives a significant economic effect.
In addition, space systems ensure the safety of citizens. More than 30,000 people, mostly of working age, die on Russian roads every year. The use of satellite navigation technologies makes it possible to optimize traffic control algorithms, the work of ambulance teams, rescuers, traffic police units, and insurance companies.
Solutions based on GLONASS technologies are being actively implemented by law enforcement agencies. This makes it possible to effectively use the forces and means available to law enforcement officers. As a result, the use of satellite navigation in the Ministry of Internal Affairs made it possible to increase the detection rate "in hot pursuit", including such serious crimes as robberies and robberies.
It is planned to use GLONASS / GPS technologies in mobile phones, smartphones with the same functions - a signal to the rescue service along with positioning information. In addition, the project "Social GLONASS" for people with disabilities is under development. handicapped, for example, with impaired vision - the system can help them navigate the streets, as well as sick children.
Without the use of modern navigation technologies, it will be difficult to ensure the competitiveness of the national economy. The global navigation system is the best fit for the role of the locomotive of innovative development of the domestic economy. Its capabilities are in demand in almost all industries - from energy and communications to construction, agriculture, and transport.
Specially organized positional and ranging synchronous observations of satellites (simultaneously from several stations) by methodssatellite geodesyallow geodetic referencing of points located thousands of km from each other, to study the movement of the continents, etc.
In 1968, the Meteor meteorological system was created in our country. It includes several satellites that are simultaneously in flight in different orbits. On board each - two television cameras. They monitor the cloud cover of the planet. On the night side of the Earth, shooting is carried out using infrared rays, which make it possible to fix the contours of the continents,seas , cloud formations. Such information is constantly transmitted to the Hydrometeorological Center. Based on them, reports and weather forecasts are compiled.
Meteorological satellites give a picture of the distribution of clouds over the entire planet, even over those territories where there are no ground meteorological stations. Butatmospheric dynamics largely associated with such deserted areas asArctic and Antarctic , hard-to-reach highlands and oceanic expanses. And one more advantage of satellites: they constantly monitor the movement of hurricanes, helping to warn residents in advance of imminent danger.
Meteorological satellites provide valuable material for farmers, pilots, sailors, fishermen - all those who are interested in weather forecasts; they bring tangible benefits to the national economy.
So, artificial satellites of the Earth help to study the Earth, rationally exploitNatural resources , protect the environment.
1.6 The largest projects of modern domestic cosmonautics
Already implemented completely or almost completely:
The following projects are under implementation:
In the short term, it is expected to start work on the following projects provided for by Roscosmos documents:
To make a model of an artificial Earth satellite, you will need two metal hemispheres, which I connected to each other using a plate and rivets. Then, I make markings for attaching antennas to the body using rectangular metal bosses with through holes, and drill them out. I flatten the television antennas purchased in advance at the base and drill similar holes in them. I also connect the satellite body with antennas using rivets.
Conclusion
Science needs astronautics - it is grandiose and a powerful tool for studying the Universe, the Earth, and man himself.
Every day the sphere of applied use of astronautics is expanding more and more. The weather service, navigation, saving people and saving forests, worldwide television, comprehensive communications, ultra-pure drugs and semiconductors from orbit, the most advanced technology - this is already today, and very close tomorrow of astronautics. And ahead - power plants in space, the removal of harmful industries from the surface of the planet, factories in near-Earth orbit and the Moon. And many many others.
Many changes have taken place in our country. The Soviet Union collapsed, the Commonwealth of Independent States was formed. Overnight, the fate of the Soviet cosmonautics turned out to be uncertain. But we must believe in the triumph of common sense. Our country was a pioneer in space exploration. space industry for a long time was with us a symbol of progress, a matter of legitimate pride for our country.
Astronautics was part of politics - our space achievements were supposed to "once again demonstrate the advantage of the socialist system." Therefore, in official reports and monographs, our achievements were described with great pomp and were modestly silent about the failures, and most importantly, the successes of our main opponents - the Americans.
Now, finally, publications have appeared truthfully, without undue pomposity and with a fair amount of self-criticism, telling about how our exploration of interplanetary space took place and we see that not everything went easily and smoothly. This in no way detracts from the achievements of our space industry - on the contrary, it testifies to the firmness and spirit of people, despite the failures of those who went to the goal. Our achievements in space will not be forgotten and will be further developed in new ideas. Astronautics is vital for all mankind!
It's a huge catalyst modern technology which has become one of the main levers of the modern world process in an unprecedentedly short period of time. It stimulates the development of electronics, mechanical engineering, materials science, computer technology, energy and many other areas of the national economy.
Research carried out on satellites and orbital complexes, research on other planets allows us to expand our understanding of the Universe, the solar system, our own planet, to understand our place in this world. Therefore, it is necessary to continue not only the exploration of space for our purely practical needs, but also fundamental research at space observatories, and research on the planets of our solar system.
Sources of information
TEN REASONS TO EXPLORE SPACE
1. Development of technologies. Hundreds of technological developments have already migrated from space to Earth and have become part of the daily lives of millions of people.
2. Scientific discoveries made through space exploration add to our knowledge of the nature of the universe and advance fundamental areas of science.
3. Space can help solve the energy problems of mankind. At the moment, the most promising option is the extraction of the helium-3 isotope on the moon.
4. The space industry employs hundreds of thousands of people in many countries. The annual turnover of the global space industry is $170 billion.
5. Direct development space program is space tourism, over the years it will become a major industry, employing many people and bringing in large profits.
6. Space is inextricably linked with military technologies; in the future, it is possible to create space weapons that will many times exceed the existing ones.
For example, kinetic weapons. A small asteroid launched from orbit would be many times worse than any atomic bomb.
7. Only with powerful space technology, it is possible to protect the planet from asteroids like those that destroyed the dinosaurs 70 million years ago.
8. The creation of bases on the Moon and Mars will become the preparation of reserve shelters for humanity in case of cataclysms on Earth. These colonies will also save the planet from an almost inevitable overpopulation.
9. Space is of great political importance, successes in extraterrestrial space raise the prestige of the country.
10. Space is a global goal, around which all of humanity can eventually unite, forever forgetting about internal ethnic and religious strife.
In astronomy and the dynamics of space flight, the concepts of three cosmic velocities are used. First cosmic speed (circular speed) is the smallest initial speed that must be reported to the body so that it becomes an artificial satellite of the planet; for the surfaces of the Earth, Mars and the Moon, the first cosmic velocities correspond to approximately 7.9 km/s, 3.6 km/s and 1.7 km/s.
second cosmic speed(parabolic speed) is the smallest initial speed that must be reported to the body so that, having started moving at the surface of the planet, it overcomes its attraction; for the Earth, Mars, and the Moon, the second space velocities are approximately 11.2 km/s, 5 km/s, and 2.4 km/s, respectively.
third cosmic speed called the smallest initial speed, with which the body overcomes the attraction of the Earth, the Sun and leaves the solar system; is approximately 16.7 km/s.
artificial satellites, in essence, are all aircraft spacecraft launched into orbits around the Earth, including spacecraft and orbital stations with crews. However, it is customary to refer to artificial satellites mainly automatic satellites that are not intended for work on them by a human astronaut. This is due to the fact that manned spacecraft differ significantly in their design features from automatic satellites. Thus, spacecraft must have life support systems, special compartments - descent vehicles in which astronauts return to Earth. For automatic satellites, this kind of equipment is not necessary or completely redundant.
The dimensions, weight, equipment of satellites depend on the tasks that satellites solve. The world's first Soviet satellite had a mass of 83.6 kg, a body in the form of a ball with a diameter of 0.58 m. The mass of the smallest satellite was 700 g.
AES are launched into orbits with the help of staged carrier rockets, which raise them to a certain height above the Earth's surface and accelerate them to a speed equal to or exceeding (but not more than 1.4 times) the first cosmic velocity. AES launches with the help of their own carrier rockets are carried out by Russia, the USA, France, Japan, China and Great Britain. A number of satellites are launched into orbits within the framework of international cooperation. Such, for example, are the Interkosmos satellites.
Movement of artificial satellites The Earth is not described by Kepler's laws, which is due to two reasons:
1) The Earth is not exactly a sphere with a uniform distribution of density over volume. Therefore, its gravitational field is not equivalent to the gravitational field of a point mass located in the geometric center of the Earth; 2) The Earth's atmosphere has a decelerating effect on the movement of artificial satellites, as a result of which their orbit changes its shape and size, and as a result, the satellites fall to the Earth.
Based on the deviation of the motion of satellites from the Keplerian one, one can draw a conclusion about the shape of the Earth, the distribution of density over its volume, and the structure of the earth's atmosphere. Therefore, it was the study of the movement of artificial satellites that made it possible to obtain the most complete data on these issues.
If the Earth were a homogeneous ball, and there would be no atmosphere, then the satellite would move in orbit, the plane retains an unchanged orientation in space relative to the system of fixed stars. The elements of the orbit in this case are determined by Kepler's laws. Since the Earth rotates, with each subsequent revolution, the satellite moves over different points on the earth's surface. Knowing the path of the satellite for any one revolution, it is not difficult to predict its position at all subsequent moments of time. To do this, it is necessary to take into account that the Earth rotates from west to east with angular velocity about 15 degrees per hour. Therefore, on the next revolution, the satellite crosses the same latitude to the west by as many degrees as the Earth turns to the east during the period of the satellite's rotation.
Due to the resistance of the earth's atmosphere, satellites cannot move for a long time at altitudes below 160 km. The minimum period of revolution at such an altitude in a circular orbit is approximately 88 minutes, that is, approximately 1.5 hours. During this time, the Earth rotates 22.5 degrees. At a latitude of 50 degrees, this angle corresponds to a distance of 1400 km. Therefore, we can say that a satellite with a period of revolution of 1.5 hours at a latitude of 50 degrees will be observed with each subsequent revolution of about 1400 km. to the west than the previous one.
However, such a calculation gives sufficient accuracy of predictions only for a few revolutions of the satellite. If we are talking about a significant period of time, then we must take into account the difference between sidereal days and 24 hours. Since one revolution around the Sun is made by the Earth in 365 days, then in one day the Earth around the Sun describes an angle of about 1 degree in the same direction in which it rotates around its axis. Therefore, in 24 hours, the Earth rotates relative to the fixed stars not by 360 degrees, but by 361 and, therefore, makes one revolution not in 24 hours, but in 23 hours 56 minutes. Therefore, the satellite track in latitude shifts to the west not by 15 degrees per hour, but by 15.041 degrees.
The circular orbit of a satellite in the equatorial plane, moving along which it is always above the same point on the equator, is called geostationary. Almost half of the earth's surface can be connected to a satellite in a synchronous orbit by rectilinearly propagating high frequency signals or light signals. Therefore, satellites in synchronous orbits are of great importance for the communication system.
HIS can be classified according to various criteria. The main principle of classification is according to the launch goals and tasks solved with the help of satellites. In addition, satellites differ in the orbits to which they are launched, the types of some onboard equipment, etc.
According to the goals and objectives of the HIS are divided into two large groups – scientific research and applied. Scientific research satellites are designed to receive new scientific information about the Earth and near-Earth outer space, to conduct astronomical research in the field of biology and medicine and other fields of science.
Applied satellites are designed to solve the practical needs of man, to obtain information in the interests of the national economy, to conduct technical experiments, as well as to test and develop new equipment.
Scientific research AES solve a wide variety of tasks for the study of the Earth, the Earth's atmosphere and near-Earth space, and celestial bodies. With the help of these satellites, important and major discoveries were made, the Earth's radiation belts, the Earth's magnetosphere, and the solar wind were discovered. Interesting research is being carried out with the help of specialized biological satellites: the influence of outer space on the development and condition of animals is being studied, higher plants, microorganisms, cells.
Are gaining more and more importance astronomical satellite. The equipment installed on these satellites is located outside the dense layers of the earth's atmosphere and makes it possible to study the radiation from celestial objects in the ultraviolet, x-ray, infrared and gamma ranges.
satellitesconnections serve to transmit television programs, messages on the Internet, provide radio - telephone, cellular, telegraph and other types of communication between ground points located on long distances from each other.
Meteorological satellites regularly transmit images of the Earth's cloud, snow and ice covers to ground stations; information about the temperature of the earth's surface and various layers of the atmosphere. These data are used to refine the weather forecast, timely warn of impending hurricanes, storms, typhoons.
Great importance acquired specialized satellites for the study of natural resources Earth. The equipment of such satellites transmits information important for various branches of the national economy. It can be used to predict crop yields, identify areas that are promising for the search for minerals, to identify pest-infested forest areas, and to control environmental pollution.
Navigational AES quickly and accurately determine the coordinates of any ground object and provide invaluable assistance in orienting on land, on water and in the air.
Military satellites can be used for space reconnaissance, for missile guidance, or as weapons themselves.
Manned spacecraft - satellites and manned orbital stations are the most complex and advanced satellites. They, as a rule, are designed to solve a wide range of tasks, primarily for conducting complex scientific research, testing space technology, studying the natural resources of the Earth, etc. The first launch of a manned satellite was carried out on April 12, 1961 on a Soviet spacecraft - satellite Vostok”, pilot-cosmonaut Yu.A. Gagarin flew around the Earth in an orbit with an apogee height of 327 km. On February 20, 1962, the first American spacecraft entered orbit with astronaut J. Genn on board.
