What is an artificial earth satellite. artificial earth satellite

On October 4, 1957, the world's first artificial Earth satellite was launched into low Earth orbit. Thus began the space age in human history. Since then, artificial satellites have been regularly helping to study the cosmic bodies of our galaxy.

Artificial Earth Satellites (AES)

In 1957, the USSR was the first to launch a satellite into Earth orbit. The USA did it second, a year later. Later, many countries launched their satellites into Earth's orbit - however, satellites purchased in the same USSR, the USA or China were often used for this. Now satellites are launched even by radio amateurs. However, many satellites have important tasks: astronomical satellites explore the galaxy and space objects, biosatellites help to conduct scientific experiments on living organisms in space, meteorological satellites make it possible to predict the weather and observe the Earth's climate, and the tasks of navigation and communication satellites are clear from their name. Satellites can be in orbit from several hours to several years: for example, manned spacecraft can become a short-term artificial satellite, and a space station can become a long-term spacecraft in Earth orbit. In total, more than 5800 satellites have been launched since 1957, 3100 of them are still in space, but only about one thousand of these three thousand are working.

Artificial satellites of the moon (ASL)

At one time, ISLs helped a lot in the study of the Moon: when entering its orbit, satellites photographed the lunar surface in high resolution and sent pictures back to Earth. In addition, by changing the trajectory of the satellites, it was possible to draw conclusions about the gravitational field of the Moon, the features of its shape and internal structure. Here Soviet Union again outstripped everyone: in 1966, the Soviet automatic station"Luna-10". And over the next three years, 5 more Soviet satellites of the Luna series and 5 American satellites of the Lunar Orbiter series were launched.

Artificial satellites of the Sun

It is curious that until the 1970s, artificial satellites appeared near the Sun ... by mistake. The first such satellite was Luna-1, which missed the Moon and entered the orbit of the Sun. And this despite the fact that it is not so easy to switch to a heliocentric orbit: the device must gain the second cosmic velocity without exceeding the third one. And approaching the planets, the device can slow down and become a satellite of the planet, or accelerate and completely leave the solar system. But now NASA satellites, orbiting the Sun near the Earth's orbit, began to perform detailed measurements of the parameters of the solar wind. The Japanese satellite observed the Sun in the X-ray range for about ten years - until 2001. Russia launched a solar satellite in 2009: Koronas-Photon will explore the most dynamic solar processes and monitor solar activity around the clock to predict geomagnetic disturbances.

Artificial satellites of Mars (IMS)

The first artificial satellites of Mars were ... three ISMs at once. Two space probes were released by the USSR ("Mars-2" and "Mars-3") and one more by the USA ("Mariner-9"). But the point is not that the launch took place "in a race" and there was such an overlay: each of these satellites had its own task. All three ISMs were launched into significantly different elliptical orbits and carried out different scientific studies, complementing each other. Mariner 9 produced a map of the surface of Mars for mapping, and Soviet satellites studied the characteristics of the planet: the solar wind flow around Mars, the ionosphere and atmosphere, relief, temperature distribution, the amount of water vapor in the atmosphere, and other data. In addition, Mars-3 was the first in the world to make a soft landing on the surface of Mars.

Artificial satellites of Venus (WIS)

The first WIS were once again Soviet spacecraft. Venera 9 and Venera 10 went into orbit in 1975. Reaching the planet. They were divided into satellites and landers. Thanks to WIS radar, scientists were able to obtain radio images from a high degree details, and the devices that gently descended on the surface of Venus took the world's first photographs of the surface of another planet ... The third satellite was the American Pioneer-Venus-1 - it was launched three years later.

Artificial earth satellites

Doing. Artificial Earth satellites are spacecraft launched into near-Earth orbits. The shape of the satellite orbits depends on the speed of the satellite and its distance from the center of the Earth and is a circle or an ellipse. In addition, the orbits differ in inclination with respect to the plane of the equator, as well as in the direction of rotation. The shape of satellite orbits is affected by the non-sphericity of the Earth's gravitational field, the gravitational fields of the Moon, the Sun and other celestial bodies, as well as the aerodynamic forces arising from the movement of satellites in the upper atmosphere, and other reasons.

The choice of the shape of the satellite orbit largely depends on its purpose and the characteristics of the tasks it performs.

Purpose of the satellite. Depending on the tasks to be solved, satellites are divided into research, applied and military ones.

Research AES serve to study the Earth, celestial bodies and outer space. With their help, geophysical, astronomical, geodetic, biological, and other studies are carried out. The orbits of such satellites are varied: from almost circular at an altitude of 200 ... 300 km to elongated elliptical with an apogee altitude of up to 500 thousand km. These are satellites Prognoz, Elektron, Proton, etc., launched into orbits to study the processes of solar activity and their influence on the Earth's magnetosphere, to study cosmic rays and the interaction of particles of supersonic energies with matter.

To applied ISZ include communication (telecommunication), meteorological, geodesic, navigation, oceanographic, geological, rescue and search and others.

Of particular importance are connected satellites- "Lightning" (Fig. 2.5), "Rainbow", "Ekran", "Horizon", designed to relay television programs and provide long-range radio communications. They use elliptical synchronous orbits with a large eccentricity. For continuous communication with the region, three such satellites should be available. Satellites "Raduga", "Ekran" and "Horizont" also have circular equatorial geostationary orbits with an altitude of 35500 - 36800 km, which provides round-the-clock communication through the network of ground receiving television stations "Orbita".

All these satellites are dynamically stabilized relative to the Earth and the Sun, which makes it possible to reliably relay the received signals, as well as to orient the solar panels (SB) to the Sun.

Rice. 2.5. Scheme of a connected artificial satellite of the Earth "Lightning":

1 - orientation system sensors; 2 - SB panels; 3 - radio receivers and transmitters;
4 - antennas; 5 - hydrazine cylinders; 6 - orbit correction engine; 7 - radiators

Meteorological AES of the Meteor type are launched into circular orbits at a height of 900 km. They register the state of the atmosphere and clouds, process the information received and transmit it to the Earth (in one revolution, the satellite surveys up to 20% of the globe).

Geodetic AES are designed for mapping the terrain and tying objects on the terrain, taking into account its relief. The composition of the onboard complex of such satellites includes: equipment that allows you to accurately fix their position in space relative to ground control points and determine the distance between them.

Navigational AES of the type "Cicada" and "Uragan" are designed for the global navigation satellite system "Glonass", "Cosmos-1000" (Russia), "Navstar" (USA) - to provide navigation for ships, aircraft and other moving objects. With the help of navigation and radio engineering systems, a ship or aircraft can determine its position relative to several satellites (or at several points in the satellite orbit). For navigation satellites, polar orbits are preferable, because they cover the entire surface of the earth.

Military AES are used to provide communications, command and control, various types of reconnaissance (surveillance of territories, military facilities, missile launches, ship movements, etc.), as well as for the navigation of aircraft, missiles, ships, submarines, etc.

AES onboard equipment. The composition of the onboard equipment of the satellite is determined by the purpose of the satellite.

The equipment may include various instruments and devices for observation. These devices, in accordance with the purpose, can operate on different physical principles. For example, a satellite can be equipped with: an optical telescope, a radio telescope, a laser reflector, photographic equipment operating in the visible and infrared ranges, etc.

To process the results of observations and analyze them, complex information-analytical complexes using computer technology and other means can be installed on board the satellite. The information received and processed on board, usually in the form of codes, is transmitted to Earth using special onboard radio complexes operating in various radio frequency bands. The radio complex may include several antennas of various types and purposes (parabolic, spiral, whip, horn, etc.).

To control the movement of a satellite and ensure the functioning of its onboard equipment, an onboard control complex is installed on board the satellite, which operates autonomously (in accordance with the programs available on board), as well as on commands received from the ground control complex.

To provide electric power to the onboard complex, as well as all onboard instruments and devices, solar panels assembled from semiconductor elements, or fuel chemical elements, or nuclear power plants are installed on the satellite.

Engine installations. Some satellites have propulsion systems used for trajectory correction or rotational stabilization. So, in order to increase the lifetime of low-orbit satellites, engines are periodically turned on on them, transferring satellites to a higher orbit.

AES orientation system. Most satellites use an orientation system that provides a fixed position of the axes with respect to the surface of the Earth or any celestial objects (for example, to study outer space using telescopes and other instruments). Orientation is carried out with the help of microrocket engines or jet nozzles located on the surface of the satellite or protruding structures (panels, trusses, etc.). Very low thrust (0.01...1 N) is required to stabilize satellites in medium and high orbits.

Design features. AES are launched into orbits under special fairings, which perceive all aerodynamic and thermal loads. Therefore, the shape of the artificial satellite and design solutions are determined by the functional expediency and allowable dimensions. AES usually have monoblock, multiblock or truss structures. Part of the equipment is placed in thermostatically sealed compartments.

Automatic interplanetary stations

Introduction. Automatic interplanetary stations (AMS) are designed for flights to the Moon and the planets of the solar system. Their features are determined by the great remoteness of functioning from the Earth (up to the exit from the sphere of action of its gravitational field) and the flight time (can be measured in years). All this imposes special requirements on their design, control, power supply, etc.

The general view and typical layout of the AMS is shown on the example of the automatic interplanetary station "Vega" (Fig. 2.6)

Rice. 2.6. General view of the automatic interplanetary station "Vega":

1 - descent vehicle; 2 - orbiter; 3 - solar battery; 4 - blocks of scientific equipment; 5 - low directional antenna; 6 - highly directional antenna

AMS flights began in January 1959 with the launch of the Soviet Luna-1 AMS into orbit, which flew to the Moon. In September of the same year, Luna 2 reached the surface of the Moon, and in October Luna 3 photographed the invisible side of the planet, transmitting these images to Earth.

In 1970 - 1976, samples of lunar soil were delivered from the Moon to Earth, and Lunokhods successfully worked on the Moon. These achievements significantly outstripped the American exploration of the Moon by automatic devices.

With the help of a series of AMSs launched towards Venus (since 1961) and Mars (since 1962), unique data were obtained on the structure and parameters of these planets and their atmosphere. As a result of AMS flights, it was found that the pressure of the atmosphere of Venus is more than 9 MPa (90 atm) and the temperature is 475°C; obtained a panorama of the planet's surface. This data was transmitted to Earth using a complex combined design. AMS, one of the parts of which descended to surface planets, and the second, launched into the orbit of the satellite, received information and broadcast it to the Earth. Similar complex studies were carried out on Mars. In the same years, rich scientific information was obtained on Earth from the Zond AMS, which worked out many design solutions for subsequent AMS, including those after their return to Earth.

Rice. 2.7. Flight trajectory of AMS "Vega" to the planet Venus and Halley's Comet

The flights of the American AMS "Ranger", "Surveyer", "Mariner", "Viking" continued the exploration of the Moon, Venus and Mars ("Mariner-9" - the first artificial satellite of Mars, went into orbit on November 13, 1971 after a successful braking maneuver , Fig. 2.9), and the Pioneer, Voyager and Galileo spacecraft reached the outer planets of the solar system: Jupiter, Saturn, Uranus, Neptune, transmitting unique images and data about these planets.

Rice. 2.9 Mariner 9, the first artificial satellite of Mars, entered orbit on November 13, 1971 after a successful deceleration maneuver:

1 - low directional antenna; 2 - maneuvering engine; 3 - fuel tank (2 pcs.); 4 - a device for orientation to the star Canopus; 5 - cylinder in the pressurization system of the propulsion system; 6 - shutters of the thermal control system; 7 - infrared interferometer-spectrometer; 8 - television camera with a small viewing angle;
9 - ultraviolet spectrometer; 10 - television camera with a large viewing angle; 11 - infrared radiometer; 12 - highly directional antenna; 13 - Sun capture sensors (4 pcs.); 14 - Sun tracking sensor; 15 - antenna with moderate gain; 16 - solar cell panel (4 pcs.).

AMC orbits. For AMS flights to the planets of the solar system, they must be given a speed close to the second space velocity or even exceeding it, while the orbit takes the form of a parabola or hyperbola. When approaching the destination planet, the AMS enters the zone of its gravitational field (gravisphere), which changes the shape of the orbit. Thus, the AMS trajectory can consist of several sections, the shape of which is determined by the laws of celestial mechanics.

Onboard equipment AMS. Depending on the tasks to be solved, a variety of instruments and devices are installed on AMS intended for planetary exploration: television cameras with a small and large viewing angle, cameras and photopolarimeters, ultraviolet spectrometers and infrared interferometers, magnetometers, detectors of cosmic rays and charged particles, devices for measuring plasma characteristics, telescopes, etc.

To perform the planned research, some scientific instruments can be located in the AMS building, others are taken out of the building with the help of trusses or rods, installed on scanning platforms, and rotated relative to the axes.

To transmit the received and processed information to the Earth, the AMS is equipped with a special transceiver radio equipment with a highly directional parabolic antenna, as well as an onboard control complex with a computing device that generates commands for the operation of devices and systems on board.

Solar panels or nuclear radioisotope thermoelectric generators (necessary for long-term flights to distant planets) can be used to provide the onboard control complex and instruments with electric power on AMS.

Design features of AMS. The supporting structure of the AMS usually has a light truss frame (platform) on which all equipment, systems and compartments are mounted. For electronic and other equipment, sealed compartments with multilayer thermal insulation and a thermal control system are used.

AWS should be equipped with a three-axis orientation system with tracking of certain landmarks (for example, the Sun, the star Canopus). AMS spatial orientation and trajectory correction maneuvers are carried out using micro-rocket engines or nozzles operating on hot or cold gases.

AMS may have an orbital maneuvering propulsion system to correct the trajectory or to transfer the AMS to the orbit of a planet or its satellite. In the latter case, the AMS design becomes much more complicated, because to land the station on the surface of the planets, its deceleration is required. It is carried out with the help of a braking propulsion system or due to the atmosphere of the planet (if its density is sufficient for braking, as on Venus). During braking and landing, there are significant loads on the structure and instruments, so the descent part is usually separated from the AMS, giving it appropriate strength and protecting it from heating and other loads.

The descent part of the AMS can have on board various research equipment, means for its movement on the surface of the planet (for example, the Lunokhod on the AMS Luna-17) and even a device returning to Earth with a soil capsule (AMS Luna-16 ). In the latter case, an additional propulsion system is installed on the reentry vehicle, which provides acceleration and correction of the reentry vehicle's trajectory.

The first artificial earth satellite

Artificial Earth satellite (AES) - revolving around in a geocentric orbit.

Movement of an artificial Earth satellite in geostationary orbit

To move in orbit around the Earth, the apparatus must have an initial velocity equal to or greater than the first cosmic velocity. AES flights are carried out at altitudes up to several hundred thousand kilometers. The lower limit of the satellite flight altitude is determined by the need to avoid the process of rapid deceleration in the atmosphere. The orbital period of a satellite, depending on the average flight altitude, can range from one and a half hours to several years. Of particular importance are satellites in geostationary orbit, the period of revolution of which is strictly equal to a day, and therefore, for a ground observer, they “hang” motionlessly in the sky, which makes it possible to get rid of rotary devices in antennas.

The concept of a satellite, as a rule, refers to unmanned spacecraft, but near-Earth manned and automatic cargo spacecraft, as well as orbital stations, in fact, are also satellites. Automatic interplanetary stations and interplanetary spacecraft can be launched into deep space both bypassing the satellite stage (the so-called right ascension) and after a preliminary ascent to the so-called. the reference orbit of the satellite.

At the beginning of the space age, satellites were launched only by means of launch vehicles, and by the end of the 20th century, the launch of satellites from other satellites - orbital stations and spacecraft (primarily from the space shuttle Space Shuttle) was also widely used. As a means of launching satellites, it is theoretically possible, but MTKK spacecraft, space guns, and space elevators have not yet been implemented. Within a short time after the beginning of the space age, it became common to launch more than one satellite on one launch vehicle, and by the end of 2013, the number of satellites launched simultaneously in some launch vehicles exceeded three dozen. During some launches, the last stages of launch vehicles also go into orbit and, for a while, actually become satellites.

Unmanned satellites have masses from several kg to two tens of tons and dimensions from several centimeters to (in particular, when using solar panels and retractable antennas) several tens of meters. Spaceships and spaceplanes that are satellites reach several tens of tons and meters, and prefabricated orbital stations reach hundreds of tons and meters. In the 21st century, with the development of microminiaturization and nano-technologies, the creation of ultra-small cubesat satellites (from one to several kg and from several to several tens of cm) has become a mass phenomenon, as well as a new pocketsat format (literally pocket) has appeared in several hundred or tens of grams and a few centimeters.

Satellites are mainly created as non-returnable, but some of them (first of all, manned and some cargo spacecraft) are partially returnable (having a descent vehicle) or completely (spaceplanes and satellites returned on board).

Artificial Earth satellites are widely used for scientific research and applied tasks (military satellites, research satellites, meteorological satellites, navigation satellites, communications satellites, biosatellite, etc.), as well as in education (university satellites have become a mass phenomenon in the world; in Russia launched satellite, created by teachers, graduate students and students of Moscow State University, it is planned to launch a satellite of Bauman Moscow State Technical University) and a hobby - amateur radio satellites. At the beginning of the space age, satellites were launched by states (national government organizations), but then satellites of private companies became widespread. With the advent of cubesats and pocketsats with launch costs of up to several thousand dollars, it became possible to launch satellites by private individuals.

AES have been launched by more than 70 different countries (as well as individual companies) using both their own launch vehicles (LV) and those provided as launch services by other countries and interstate and private organizations.

The world's first satellite was launched in the USSR on October 4, 1957 (Sputnik-1). The second country to launch a satellite was the United States on February 1, 1958 (Explorer 1). The following countries- Great Britain, Canada, Italy - launched their first satellites in 1962, 1962, 1964. respectively, on American launch vehicles. The third country that launched the first satellite on its launch vehicle was France on November 26, 1965 (Asterix). Australia and Germany acquired the first satellites in 1967 and 1969. respectively also with the help of the US PH. Japan, China, Israel launched their first satellites on their launch vehicles in 1970, 1970, 1988. A number of countries - Great Britain, India, Iran, as well as Europe (the interstate organization ESRO, now ESA) - launched their first artificial satellites on foreign carriers before they created their own launch vehicles. The first satellites of many countries were developed and purchased in other countries (USA, USSR, China, etc.).

There are the following types of satellites:

Astronomical satellites are satellites designed to study planets, galaxies and other space objects.
Biosatellites are satellites designed to conduct scientific experiments on living organisms in space.
Earth remote sensing
Spaceships - manned spacecraft
Space stations - long-term spacecraft
Meteorological satellites are satellites designed to transmit data for the purpose of predicting the weather, as well as for observing the Earth's climate.
Small satellites - satellites of small weight (less than 1 or 0.5 tons) and size. They include minisatellites (more than 100 kg), microsatellites (more than 10 kg) and nanosatellites (lighter than 10 kg), incl. cubesats and pocketsats.
reconnaissance satellites
Navigation satellites
Communications satellites
Experimental satellites

On February 10, 2009, for the first time in history, a satellite collision occurred. A Russian military satellite (launched into orbit in 1994 but decommissioned two years later) and a working American satellite of the Iridium satellite telephone operator collided. "Cosmos-2251" weighed almost 1 ton, and "Iridium 33" 560 kg.

Satellites collided in the sky over the northern part of Siberia. As a result of the collision, two clouds were formed from small debris and fragments ( total fragments amounted to about 600).

Artificial earth satellites (ISZ)

space aircrafts, put 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, 1957, and was the result of achievements in the field of rocket technology, electronics, automatic control, computer technology, celestial mechanics, and other branches 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, 1958, 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, widespread the international cooperation. 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.

General information about the satellite. 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 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 the satellite is equipped with radio transmitters, one or another measuring equipment, flash lamps for supplying light signals, etc., it is called active. Passive satellites are usually designed for observations with earth's surface when solving some scientific problems (such satellites include balloon satellites, reaching a diameter of several tens m). Research satellites are used to study the Earth, celestial bodies, and outer space. These include, in particular, geophysical satellites (See. Geophysical satellite), Geodetic satellites, orbiting astronomical observatories, etc. Applied satellites are Communications satellite and, meteorological satellites (See. Meteorological satellite), satellites for the study of terrestrial resources, navigation satellites (See Navigation satellite), satellites for technical purposes (for studying the effect of space conditions on materials, for testing and working out on-board systems), and other artificial satellites intended 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.

In accordance with international system registration of space objects (satellites, space probes (See Space probes), etc.) within the framework of the international organization COSPAR in 1957-1962, space objects were designated by the year of launch with the addition of a letter of the Greek alphabet corresponding to the serial number of the launch in this year, and an Arabic numeral - the number of the orbital object, depending on its brightness or degree of scientific significance. So, 1957α2 is the designation of the first Soviet satellite, launched in 1957; 1957α1 - the designation of the last stage of the launch vehicle of this satellite (the launch vehicle was brighter). As the number of launches increased, starting from January 1, 1963, space objects began to be designated by the year of launch, by the serial number of the launch in a given year, and by a capital letter of the 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.

In accordance with the variety of scientific and applied problems solved with the help of satellites, satellites can have different sizes, weights, design schemes, and composition of onboard 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, the 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.

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-term operation of onboard 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 a small heat release of equipment in some cases are limited passive means thermal control (selection of an external surface with a suitable optical coefficient, thermal insulation of individual elements).

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.

ISZ movement. 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 of the earth's atmosphere at a relatively low speed (which reduces the energy costs of overcoming 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 greater than (but not more than 1.4 times) the first cosmic velocity (See Cosmic velocities) (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, the pressure of solar radiation, the attraction of the moon and the sun, are the cause of deviations from 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.

AES observations. 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 a satellite with an accuracy of several minutes of arc. To solve scientific problems, photographic observations are carried out with the help of satellite cameras (See Satellite camera), which ensure the 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.

Research satellites. 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, Cosmos 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 for solving such practical issues as radio communication forecast, forecast of the state of the upper atmosphere, etc.

With the help of satellites, the Earth's radiation belts have been discovered and are being studied. Along with space probes, satellites made it possible to study the structure of the Earth's magnetosphere (see Earth's magnetosphere) and the nature of the solar wind flow around it, as well as the characteristics of the solar wind itself (see Solar wind) (flux density and energy of particles, the magnitude and nature of the "frozen" 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 of 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) by satellite geodesy methods (See Satellite geodesy) make it possible to carry out geodetic referencing of points thousands of km from each other, to study the movement of the continents, etc.

Applied HIS. 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 above certain areas of the earth's surface.

Meteorological satellites are designed for regular transmission to ground stations of television images of the Earth's cloudy, snow and ice cover, information about the thermal radiation of the earth's surface and clouds, etc. AES of this type are launched into orbits close to circular, with an altitude 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 in terms of application in national economy are satellites for exploration natural resources Earth. Along with meteorological, oceanographic and hydrological observations, such satellites make it possible to obtain operational information necessary for geology, Agriculture, fisheries, forestry, pollution control natural environment. 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 support system, are used for navigation sea ​​ships, including underwater ones. 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".

Manned satellite ships. 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, on which in June 1971 the crew consisting of G. T. Dobrovolsky, V. N. Volkov and V. I. Patsaev completed a wide program of scientific and technical , biomedical and other research.

N. P. Erpylev, M. T. Kroshkin, Yu. A. Ryabov, E. F. Ryazanov.

AES "Cosmos"

"Kosmos" is the name of a series of Soviet artificial Earth satellites for scientific, technical and other research in near-Earth space. The Cosmos satellite launch program includes the study of cosmic rays, the radiation belt of the Earth and the ionosphere, the propagation of radio waves and other radiation in the Earth's atmosphere, solar activity and solar radiation in various parts of the spectrum, and the development of nodes spacecraft and elucidation of the influence of meteoric matter on the structural elements of a spacecraft, the study of the influence of weightlessness and other space factors on biological objects, etc. Such a broad research program and, consequently, a large number of launches set before engineers and designers the task of limiting the unification of the design of the servicing systems of artificial satellites Kosmos. The solution of this problem made it possible to use a single body, a standard composition of service systems, a common control scheme for on-board equipment, a unified power supply system and a number of other unified systems and devices for the implementation of some launch programs. This made it possible to mass-produce Cosmos and its component systems, simplified the preparation for the launch of satellites, and significantly reduced the cost of scientific research.

Cosmos satellites are launched into circular and elliptical orbits, the altitude range of which is from 140 (Cosmos-244) to 60600 km (Cosmos-159) and a wide range of orbital inclinations from 0.1° (Cosmos-775) up to 98° (“Kosmos-1484”) allows delivering scientific equipment to almost all areas of near-Earth outer space. The orbital periods of the Cosmos satellites are from 87.3 minutes (Cosmos-244) to 24 hours 2 minutes (Cosmos-775). The time of active operation of the Kosmos satellite depends on scientific programs their launch, orbital parameters and onboard systems operation resources. For example, Cosmos-27 was in orbit for 1 day, and Cosmos-80, according to calculations, will exist for 10 thousand years.

Orientation of artificial earth satellites "Cosmos" depends on the nature of the research. To solve such problems as meteorological experiments, the study of the spectrum of radiation leaving the Earth, and others, satellites with an orientation relative to the Earth are used. When studying the processes occurring on the Sun, the Cosmos modifications are applied with an orientation to the Sun. Satellite orientation systems are different - reactive ( rocket engines), inertial (flywheel rotating inside the satellite) and others. The highest orientation accuracy is achieved by combined systems. The transmission of information is carried out mainly in the ranges of 20, 30 and 90 MHz. Some satellites are equipped with a TV connection.

In accordance with the tasks to be solved, a number of satellites of the Cosmos series have a descent capsule for returning scientific equipment and experimental objects to Earth (Cosmos-4, -110, -605, -782 "and others). The descent of the capsule from orbit is provided by a brake propulsion system with a preliminary orientation of the satellite. Subsequently, the capsule is decelerated in dense layers of the atmosphere due to aerodynamic force, and at a certain height the parachute system is activated.

On satellites Kosmos-4, -7, -137, -208, -230, -669 and others, a program was carried out to study primary cosmic rays and the Earth's radiation belt, including measurements to ensure radiation safety during manned flights (for example, on "Cosmos-7" during the flight of the spacecraft "Vostok-3, -4"). The flights "Cosmos-135" and "Cosmos-163" finally dispelled the long-standing assumption about the existence of a dust cloud around the Earth. Artificial satellites "Cosmos" are widely used to solve national economic problems. For example, "Studying the distribution and formation of cloud systems in the Earth's atmosphere" is one of the items in the Cosmos satellite launch program. Work in this direction, as well as the accumulated experience in the operation of satellites "Kosmos-14, -122, -144, -156, -184, -206" and others led to the creation of meteorological satellites "Meteor", and then - the meteorological space system "Meteor ". Satellites "Cosmos" are used in the interests of navigation, geodesy and more.

A significant number of experiments on these satellites are related to the study of the upper atmosphere, the ionosphere, the radiation of the Earth and other geophysical phenomena (for example, the study of the distribution of water vapor in the mesosphere - on "Kosmos-45, -65", the study of the passage of ultra-long radio waves through the ionosphere - on the "Kosmos -142", observation of thermal radio emission of the Earth's surface and study of the earth's atmosphere by its own radio and submillimeter radiation - on "Kosmos-243, -669"; mass spectrometric experiments - on "Kosmos-274"). On the satellites "Kosmos-166, -230" studies of the X-ray radiation of the Sun, including during solar flares, were carried out, on the "Kosmos-215" the scattering of Lyman-alpha radiation in the geocorona was studied (8 small telescopes were installed on the satellite), Cosmos-142 studied the dependence of the intensity of cosmic radio emission on a number of factors. On some satellites "Cosmos" experiments were carried out to study meteor particles ("Cosmos-135" and others). On satellites "Kosmos-140, -656" and others, tests were carried out on a superconducting magnetic system with a field strength of up to 1.6 MA/m, which can be used to analyze charged particles with energies up to several GeV. The same satellites were used to study liquid helium, which was in a supercritical state. Satellites "Kosmos-84, -90" had isotope generators as part of their power supply systems. An on-board quantum molecular generator was installed on the Kosmos-97 satellite, experiments with which made it possible to increase the accuracy of the ground-space system of common time by several orders of magnitude, the sensitivity of the receiving equipment and the stability of the frequency of radio waves of transmitters.

Medical and biological experiments were carried out on a number of Kosmos satellites, which made it possible to determine the degree of influence of factors space flight on the functional state of biological objects - from unicellular algae, plants and their seeds ("Cosmos-92, -44, -109") to dogs and other animals ("Cosmos-110, -782, -936"). The study of the results of these studies, together with the data of medical observations of the human body in space, helps to develop the most favorable regimes for work, rest, nutrition for astronauts, to create the necessary equipment for the spacecraft, and for the crews of the spacecraft - clothing and food. Cosmos-690 was used to study the effect of radiation on living organisms, and to simulate powerful solar flares, a radiation source (cesium-137) with an activity of 1.2-1014 disperses per second was used on board the satellite. A centrifuge with a diameter of 60 cm was installed on the Kosmos-782 satellite, with the help of which the possibility of creating arts, gravity and its influence on biological objects was studied. On a number of biological satellites (for example, Kosmos-605, -690 and others)

Some satellites of the Earth "Cosmos" were tested as unmanned spacecraft. During the joint flight of the Kosmos-186 and Kosmos-188 satellites in October 1967, for the first time in the world, they performed automatic rendezvous and docking in orbit; after undocking, their autonomous flight was continued and the descent vehicles landed on the territory of the USSR. In April 1968, automatic docking in orbit was carried out during the flight of Kosmos-212 and Kosmos-213 - both satellites (descent vehicles) also landed on the territory of the USSR. In June 1981, in order to test the onboard systems of the new spacecraft with the Salyut-6 orbital station, the Cosmos-1267 satellite was docked. Until 29.7.1982 orbital station and the artificial satellite were in a docked state. On satellites of the Kosmos series, separate systems were worked out and the equipment of many other spacecraft was tested. So, at Kosmos-41, some elements of the design of the Molniya communication satellites were worked out, which, in combination with the receiving-transmitting and antenna devices specially created at earth stations, now form a permanent system of deep space communications, Kosmos-1000 performed navigation tasks . Separate components of the lunar rover were worked out on the Kosmos satellites.

With the launches of artificial earth satellites "Kosmos", practical international cooperation of the socialist countries in the study of outer space began. The main task of the Kosmos-261 satellite launched in December 1968 was to conduct a complex experiment, including direct measurements on the satellite, in particular, the characteristics of electrons and protons that cause auroras, and variations in the density of the upper atmosphere during these auroras, and ground-based studies of auroras . Participated in this work scientific institutes and observatories of the NRB, VNR, GDR, Poland, SRR, USSR and Czechoslovakia. Experts from France, the USA and other countries also took part in the experiments on satellites of this series.

Earth satellites "Cosmos" have been launched since 1962 with the help of carrier rockets "Cosmos", "Soyuz", "Proton" and others, capable of delivering a payload weighing up to several tons into orbit. Until 1964, the Cosmos satellites were also launched into orbit by the Vostok launch vehicle. On January 1, 1984, 1521 artificial earth satellites "Kosmos" were launched.