Space satellites of the earth. Interesting facts about artificial earth satellites

Artificial Earth satellites are spacecraft that are launched onto and revolve around it in a geocentric orbit. They are intended for solving applied and scientific problems. The first launch of an artificial Earth satellite took place on October 4, 1957 in the USSR. It was the first artificial celestial body that people created. The event became possible thanks to the results of achievements in many areas of rocketry, computer technology, electronics, celestial mechanics, automatic control and other branches of science. The first satellite made it possible to measure the density of the upper layers of the atmosphere, verify the reliability of theoretical calculations and the main technical solutions that were used to put the satellite into orbit, and study the features of radio signal transmission in the ionosphere.

America launched its first satellite "Explorer-1" on February 1, 1958, and then, a little later, other countries launched: France, Australia, Japan, China, Great Britain. Cooperation between the countries of the whole world has become widespread in the region.

A spacecraft can only be called a satellite after it has completed more than one revolution around the Earth. Otherwise, it is not registered as a satellite and will be called a rocket probe, which carried out measurements on ballistic trajectory.

A satellite is considered active if radio transmitters, flash lamps that give light signals, and measuring equipment are installed on it. Passive artificial Earth satellites are often used for observations from the planet's surface when performing certain scientific tasks. These include balloon satellites up to several tens of meters in diameter.

Artificial Earth satellites are divided into applied and research, depending on the tasks they perform. Scientific-research are intended for carrying out researches of the Earth, outer space. These are geodetic and geophysical satellites, astronomical orbital observatories, etc. Applied satellites are communication satellites, navigational for the study of the Earth's resources, technical, etc.

Artificial satellites of the Earth, created for human flight, are called "manned spacecraft-satellites". AES in a subpolar or polar orbit are called polar, and in an equatorial orbit - equatorial. Stationary satellites are satellites launched into an equatorial circular orbit, the direction of movement of which coincides with the rotation of the Earth, they hang motionless over a specific point on the planet. Parts separated from the satellites during launch into orbit, such as nose fairings, are secondary orbital objects. They are often referred to as satellites, even though they move along near-Earth orbits and serve primarily as objects for observation for scientific purposes.

From 1957 to 1962 the name of space objects indicated the year of launch and the letter of the Greek alphabet corresponding to the serial number of the launch in a particular year, as well as Arabic numeral- number of the object, depending on its scientific significance or brightness. But the number of launched satellites grew rapidly, therefore, from January 1, 1963, they began to be designated by the launch year, the launch number in the same year and the letter Latin alphabet.

Satellites can be different in size, design schemes, mass, composition of onboard equipment, depending on the tasks performed. The power supply of the equipment of almost all satellites is produced by means of solar batteries installed on the outer part of the case.

AES are put into orbit by means of automatically controlled multi-stage launch vehicles. The movement of artificial satellites of the Earth is subject to passive (attraction of planets, resistance, etc.) and active (if the satellite is equipped with forces.

Spacecraft in all their diversity is both the pride and concern of mankind. Their creation was preceded by a centuries-old history of the development of science and technology. The space age, which allowed people to look at the world they live in from the outside, lifted us to a new stage of development. A rocket in space today is not a dream, but an object of concern for highly qualified specialists who are faced with the task of improving existing technologies. What types of spacecraft are distinguished and how they differ from each other will be discussed in the article.

Definition

Spacecraft - a generalized name for any device designed to operate in space. There are several options for their classification. In the simplest case, manned and automatic spacecraft are distinguished. The former, in turn, are subdivided into spaceships and stations. Different in their capabilities and purpose, they are similar in many respects in terms of structure and equipment used.

Flight features

Any spacecraft after launch goes through three main stages: launching into orbit, actual flight and landing. The first stage involves the development by the apparatus of the speed necessary for entering outer space. In order to get into orbit, its value must be 7.9 km / s. The complete overcoming of the earth's gravity involves the development of a second equal to 11.2 km / s. This is how a rocket moves in space when its target is remote parts of the space of the Universe.

After the release from attraction, the second stage follows. In the process of orbital flight, the movement of spacecraft occurs by inertia, due to the acceleration given to them. Finally, the landing stage involves reducing the speed of the ship, satellite or station to almost zero.

"Filling"

Each spacecraft is equipped with equipment to match the tasks that it is designed to solve. However, the main discrepancy is related to the so-called target equipment, which is necessary just for obtaining data and various scientific research. The rest of the equipment of the spacecraft is similar. It includes the following systems:

• energy supply - most often solar or radioisotope batteries, chemical batteries, nuclear reactors supply spacecraft with the necessary energy;
• communication - carried out using a radio wave signal, at a significant distance from the Earth, accurate pointing of the antenna becomes especially important;
• life support - the system is typical for manned spacecraft, thanks to it it becomes possible for people to stay on board;
• orientation - like any other ships, space ships are equipped with equipment for constantly determining their own position in space;
• movement - spacecraft engines allow you to make changes in the speed of flight, as well as in its direction.

Classification

One of the main criteria for dividing spacecraft into types is the mode of operation that determines their capabilities. On this basis, devices are distinguished:

• located in a geocentric orbit, or artificial satellites of the Earth;
• those whose purpose is to study remote areas of space - automatic interplanetary stations;
• used to deliver people or the necessary cargo to the orbit of our planet, they are called spacecraft, they can be automatic or manned;
• created for people to stay in space for a long period - this;
• engaged in the delivery of people and cargo from orbit to the surface of the planet, they are called descent;
• able to explore the planet, directly located on its surface, and move around it - these are planetary rovers.

Let's take a closer look at some types.

AES (artificial Earth satellites)

The first vehicles launched into space were artificial earth satellites. Physics and its laws make launching any such device into orbit a daunting task. Any apparatus must overcome the gravity of the planet and then not fall on it. To do this, the satellite needs to move with or slightly faster. Above our planet, a conditional lower limit of the possible location of an artificial satellite is distinguished (passes at an altitude of 300 km). A closer placement will lead to a fairly rapid deceleration of the apparatus in atmospheric conditions.

Initially, only launch vehicles could deliver artificial earth satellites into orbit. Physics, however, does not stand still, and today new methods are being developed. So, one of the methods often used recently is launching from another satellite. There are plans to use other options.

The orbits of spacecraft revolving around the Earth can lie at different heights. Naturally, the time required for one circle also depends on this. Satellites with a period of revolution equal to a day are located on the so-called It is considered the most valuable, since the devices located on it seem to be stationary for an earthly observer, which means that there is no need to create mechanisms for rotating antennas.

AMS (automatic interplanetary stations)

A huge amount of information about various objects solar system scientists receive with the help of spacecraft sent outside the geocentric orbit. AMC objects are planets, asteroids, comets, and even galaxies available for observation. The tasks that are set for such devices require enormous knowledge and effort from engineers and researchers. AWS missions represent the embodiment of technological progress and are at the same time its stimulus.

manned spacecraft

Apparatuses designed to deliver people to a designated target and return them back are in no way inferior to the described types in terms of technology. It is to this type that Vostok-1 belongs, on which Yuri Gagarin made his flight.

The most difficult task for the creators of a manned spaceship- ensuring the safety of the crew during the return to Earth. Also significant part such devices is an emergency rescue system, which may be necessary during the launch of the ship into space using a launch vehicle.

Spacecraft, like all astronautics, are constantly being improved. Recently, one could often see reports in the media about the activities of the Rosetta probe and the Philae lander. They embody all the latest achievements in the field of space shipbuilding, calculation of the movement of the apparatus, and so on. The landing of the Philae probe on a comet is considered an event comparable to Gagarin's flight. The most interesting thing is that this is not the crown of humanity's possibilities. We are still waiting for new discoveries and achievements in terms of both space exploration and construction

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 influenced 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 a height 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 with respect 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 Meteor-type satellites 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 (for one revolution, the satellite surveys up to 20% of the area 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, implementation various kinds reconnaissance (surveillance of territories, military installations, 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 can have several antennas various types and destinations (parabolic, spiral, pin, 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.

General form and the 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, entered 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.

We have long been accustomed to the fact that we live in the era of space exploration. However, watching huge reusable rockets and space orbital stations today, many do not realize that the first launch spacecraft took place not so long ago - only 60 years ago.

Who launched the first artificial earth satellite? - USSR. This question is of great importance, since this event gave rise to the so-called space race between the two superpowers: the USA and the USSR.

What was the name of the world's first artificial earth satellite? - since such devices did not previously exist, Soviet scientists considered that the name "Sputnik-1" was quite suitable for this device. The code designation of the device is PS-1, which stands for "The Simplest Sputnik-1".

Externally, the satellite had a rather uncomplicated appearance and was an aluminum sphere with a diameter of 58 cm to which two curved antennas were attached crosswise, allowing the device to spread radio emission evenly and in all directions. Inside the sphere, made of two hemispheres fastened with 36 bolts, there were 50-kilogram silver-zinc batteries, a radio transmitter, a fan, a thermostat, pressure and temperature sensors. The total weight of the device was 83.6 kg. It is noteworthy that the radio transmitter broadcast in the range of 20 MHz and 40 MHz, that is, ordinary radio amateurs could follow it.

History of creation

The history of the first space satellite and space flights in general begins with the first ballistic missile- V-2 (Vergeltungswaffe-2). The rocket was developed by the famous German designer Wernher von Braun at the end of World War II. The first test launch took place in 1942, and the combat one in 1944, a total of 3225 launches were made, mainly in the UK. After the war, Wernher von Braun surrendered to the US Army, in connection with which he headed the Arms Design and Development Service in the United States. Back in 1946, a German scientist presented to the US Department of Defense a report “Preliminary design of an experimental spacecraft orbiting the Earth”, where he noted that a rocket capable of launching such a ship into orbit could be developed within five years. However, funding for the project was not approved.

On May 13, 1946, Joseph Stalin adopted a resolution on the creation of a rocket industry in the USSR. Sergei Korolev was appointed chief designer of ballistic missiles. For the next 10 years, scientists developed intercontinental ballistic missiles R-1, R2, R-3, etc.

In 1948, rocket designer Mikhail Tikhonravov gave a report to the scientific community on composite rockets and the results of calculations, according to which the developed 1000-kilometer rockets can reach great distances and even put an artificial Earth satellite into orbit. However, such a statement was criticized and was not taken seriously. Tikhonravov's department at NII-4 was disbanded due to irrelevant work, but later, through the efforts of Mikhail Klavdievich, it was reassembled in 1950. Then Mikhail Tikhonravov spoke directly about the mission to put a satellite into orbit.

satellite model

After the creation of the R-3 ballistic missile, its capabilities were presented at the presentation, according to which the missile was capable of not only hitting targets at a distance of 3000 km, but also launching a satellite into orbit. So by 1953, scientists still managed to convince top management that the launch of an orbiting satellite was possible. And the leaders of the armed forces had an understanding of the prospects for the development and launch of an artificial Earth satellite (AES). For this reason, in 1954, a decision was made to create a separate group at NII-4 with Mikhail Klavdievich, which would be engaged in satellite design and mission planning. In the same year, Tikhonravov's group presented a space exploration program, from the launch of an artificial satellite to landing on the moon.

In 1955, a delegation of the Politburo headed by N. S. Khrushchev visited the Leningrad Metal Plant, where the construction of the two-stage rocket R-7 was completed. The impression of the delegation resulted in the signing of a resolution on the creation and launch of a satellite into earth orbit in the next two years. The design of the artificial satellite began in November 1956, and in September 1957 the Simplest Sputnik-1 was successfully tested on a vibration stand and in a heat chamber.

Definitely to the question "who invented Sputnik-1?" — cannot be answered. The development of the first satellite of the Earth took place under the leadership of Mikhail Tikhonravov, and the creation of the launch vehicle and the launch of the satellite into orbit - under the leadership of Sergei Korolev. However, a considerable number of scientists and researchers worked on both projects.

Launch history

In February 1955, the top management approved the creation of the Scientific Research Test Site No. 5 (later Baikonur), which was to be located in the Kazakhstan desert. The first ballistic missiles of the R-7 type were tested at the test site, but according to the results of five experimental launches, it became clear that the massive warhead of the ballistic missile could not withstand the temperature load and needed to be improved, which would take about six months. For this reason, S.P. Korolev requested two rockets from N.S. Khrushchev for the experimental launch of PS-1. At the end of September 1957, the R-7 rocket arrived at Baikonur with a lightened head and a passage under the satellite. Extra equipment was removed, as a result of which the mass of the rocket was reduced by 7 tons.

On October 2, S.P. Korolev signed the order on flight tests of the satellite and sent a notice of readiness to Moscow. And although no answers came from Moscow, Sergei Korolev decided to bring the Sputnik launch vehicle (R-7) from PS-1 to the starting position.

The reason why the management demanded that the satellite be put into orbit during this period is that from July 1, 1957 to December 31, 1958, the so-called International Geophysical Year was held. According to it, during the specified period, 67 countries jointly and under a single program carried out geophysical research and observations.

The launch date of the first artificial satellite is October 4, 1957. In addition, on the same day, the opening of the VIII International Astronautical Congress took place in Spain, Barcelona. The leaders of the USSR space program were not disclosed to the public due to the secrecy of the work being carried out; Academician Leonid Ivanovich Sedov informed Congress about the sensational launch of the satellite. Therefore, it was the Soviet physicist and mathematician Sedov that the world community has long considered the "father of Sputnik."

Flight history

At 22:28:34 Moscow time, a rocket with a satellite was launched from the first site of NIIP No. 5 (Baikonur). After 295 seconds, the central block of the rocket and the satellite were launched into an elliptical Earth orbit (apogee - 947 km, perigee - 288 km). After another 20 seconds, PS-1 separated from the missile and gave a signal. It was the repeated signals of “Beep! Beep!”, which were caught at the range for 2 minutes, until Sputnik-1 disappeared over the horizon. On the first orbit of the apparatus around the Earth, the Telegraph Agency of the Soviet Union (TASS) transmitted a message about the successful launch of the world's first satellite.

After receiving the PS-1 signals, detailed data began to come in about the device, which, as it turned out, was close to not reaching the first space velocity and not entering orbit. The reason for this was an unexpected failure of the fuel control system, due to which one of the engines was late. A fraction of a second separated from failure.

However, PS-1 nevertheless successfully reached an elliptical orbit, along which it moved for 92 days, while completing 1440 revolutions around the planet. The radio transmitters of the device worked during the first two weeks. What caused the death of the first satellite of the Earth? - Having lost speed due to the friction of the atmosphere, Sputnik-1 began to descend and completely burned out in the dense layers of the atmosphere. It is noteworthy that many could observe some kind of brilliant object moving across the sky at that time. But without special optics, the shiny body of the satellite could not be seen, and in fact this object was the second stage of the rocket, which also rotated in orbit, along with the satellite.

The meaning of flight

The first launch of an artificial Earth satellite in the USSR produced an unprecedented rise in pride in their country and a strong blow to the prestige of the United States. An excerpt from the United Press publication: “90 percent of the talk about artificial satellites The land was owned by the United States. As it turned out, 100 percent of the case fell on Russia ... ". And despite the erroneous ideas about the technical backwardness of the USSR, it was the Soviet apparatus that became the first satellite of the Earth, moreover, its signal could be tracked by any radio amateur. The flight of the first Earth satellite marked the beginning of the space age and launched the space race between the Soviet Union and the United States.

Just 4 months later, on February 1, 1958, the United States launched its Explorer 1 satellite, which was assembled by the team of scientist Wernher von Braun. And although it was several times lighter than the PS-1 and contained 4.5 kg of scientific equipment, it was still the second one and no longer had such an impact on the public.

Scientific results of PS-1 flight

The launch of this PS-1 had several goals:

• Testing the technical ability of the apparatus, as well as checking the calculations made for the successful launch of the satellite;
• Research of the ionosphere. Before the launch of the spacecraft, radio waves sent from the Earth were reflected from the ionosphere, making it impossible to study it. Now, scientists have been able to begin exploring the ionosphere through the interaction of radio waves emitted by a satellite from space and traveling through the atmosphere to the Earth's surface.
• Calculation of the density of the upper layers of the atmosphere by observing the rate of deceleration of the apparatus due to friction against the atmosphere;
• Study of the influence of outer space on equipment, as well as determining favorable conditions for the operation of equipment in space.

Listen to the sound of the First Satellite

And although the satellite did not have any scientific equipment, tracking its radio signal and analyzing its nature yielded many useful results. So a group of scientists from Sweden measured the electronic composition of the ionosphere, based on the Faraday effect, which says that the polarization of light changes when it passes through a magnetic field. Also, a group of Soviet scientists from Moscow State University developed a method for observing the satellite with an accurate determination of its coordinates. Observation of this elliptical orbit and the nature of its behavior made it possible to determine the density of the atmosphere in the region orbital altitudes. The unexpectedly increased density of the atmosphere in these areas prompted scientists to create a theory of satellite deceleration, which contributed to the development of astronautics.

Video about the first satellite.

On the outside"Satellite" four whip antennas transmitted at a shortwave frequency 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, the Soviet Union launched Sputnik 2 into orbit. Inside the capsule was the dog Laika.

In December 1957, desperately trying to keep up with his opponents on cold war, American scientists tried to put the 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 the new system to speak with the Nigerian Prime Minister in Africa. Syncom-3 soon took off, which could actually broadcast a television signal.

The era of satellites has begun.

What's the difference between a satellite and space junk?

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 - they revolve around the planet for 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:

• The rocket explosion that produces the most junk.
• The astronaut relaxed his hand - if an astronaut is repairing something in space and misses a wrench, that wrench is lost forever. The key goes into orbit and flies at a speed of about 10 km/s. If it hits a person or a satellite, the results can be catastrophic. Large objects like the ISS are a big target for space debris.
• Discarded items. Parts of launch containers, camera lens caps, and so on.

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.

What's inside an ordinary satellite?

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 a radio 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.

How are satellites launched into orbit?

Today, all satellites are launched into orbit on a rocket. Many transport them in the cargo department.

In most satellite launches, the rocket launches directly upwards, 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.

Orbital speed and height

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 the earth, the faster 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 resistance. At high altitude, there is practically no resistance, and a satellite, like the moon, can be in orbit for centuries.

Satellite types

On the ground, all satellites look the same - shiny boxes or cylinders adorned with solar panel wings. 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 complete orbit 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 earth's surface. Based on this scheme, there are three categories:

• Low Earth orbit (LEO) - LEO satellites occupy a region of space from 180 to 2000 kilometers above the Earth. Satellites that move close to the Earth's surface are ideal for observational, military and weather information gathering purposes.
• Medium Earth Orbit (MEO) - These satellites fly from 2,000 to 36,000 km above the Earth. GPS navigation satellites work well at this altitude. The approximate orbital speed is 13,900 km/h.
• Geostationary (geosynchronous) orbit - geostationary satellites move around the Earth at an altitude exceeding 36,000 km and at the same rotation speed as the planet. Therefore, satellites in this orbit are always positioned to the same place on Earth. Many geostationary satellites fly along the equator, which has created a lot of "traffic jams" in this region of space. Several hundred television, communications and weather satellites use the geostationary orbit.

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, as well as scan for objects like asteroids and comets that could collide with Earth.

Known satellites

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 daily life. Thanks to them, we find out 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.

1. Landsat satellites have been photographing the Earth since the early 1970s, and in terms of observations of the Earth's surface, they are champions. Landsat-1, known at the time as ERTS (Earth Resources Technology Satellite), was launched on July 23, 1972. It carried two main instruments: a camera and a multispectral scanner built by the Hughes Aircraft Company and capable of recording data in green, red and two infrared spectra. The satellite took such gorgeous images and was considered so successful that a whole series followed it. NASA launched the last Landsat-8 in February 2013. This vehicle flew two Earth-observing sensors, Operational Land Imager and Thermal Infrared Sensor, collecting multispectral images of coastal regions, polar ice, islands and continents.
2. Geostationary Operational Environmental Satellites (GOES) circle the Earth in geostationary orbit, each responsible for a fixed portion of the globe. This allows satellites to closely observe the atmosphere and detect changes weather conditions, which can lead to tornadoes, hurricanes, floods and lightning storms. Satellites are also used to estimate the amount of precipitation and snow accumulation, measure the degree of snow cover and track the movement of sea and lake ice. Since 1974, 15 GOES satellites have been launched into orbit, but only two GOES West and GOES East satellites are monitoring the weather at the same time.
3. Jason-1 and Jason-2 have played a key role in the long-term analysis of the Earth's oceans. NASA launched Jason-1 in December 2001 to replace the NASA/CNES Topex/Poseidon satellite that had been orbiting Earth since 1992. For nearly thirteen years, Jason-1 has measured sea levels, wind speeds and wave heights in more than 95% of Earth's ice-free oceans. NASA officially retired Jason-1 on July 3, 2013. Jason 2 entered orbit in 2008. It carried precision instruments to measure the distance from the satellite to the ocean surface with an accuracy of a few centimeters. These data, in addition to being valuable to oceanographers, provide an extensive look at the behavior of the world's climate patterns.

How much do satellites cost?

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 to 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.

Another important factor is 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.

The future of satellites

Almost fifty years after the launch of Sputnik, satellites, like budgets, are growing and getting stronger. The US, for example, has spent nearly $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 transmission speed of 622 megabits per second.