Artificial satellites of the Earth are flying spacecraft that are launched onto and rotate around it in a geocentric orbit. They are intended to solve applied and scientific problems. The first launch of an artificial Earth satellite took place on October 4, 1957 in the USSR. This was the first artificial celestial body created by people. The event was made possible thanks to the results of achievements in many areas of rocketry, computer technology, electronics, celestial mechanics, automatic control and other areas of science. The first satellite made it possible to measure the density of the upper layers of the atmosphere, check the reliability of theoretical calculations and the main technical solutions that were used to launch 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 also launched: France, Australia, Japan, China, and Great Britain. Cooperation between countries around the world has become widespread in the region.

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

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

Artificial Earth satellites are divided into applied and scientific research, depending on the tasks they perform. Scientific research is designed to conduct research on the Earth and outer space. These are geodetic and geophysical satellites, astronomical orbital observatories, etc. Applied satellites are communication satellites, navigation satellites for studying Earth resources, technical satellites, etc.

Artificial Earth satellites created for human flight are called “manned satellites”. Satellites 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 satellites during launch into orbit, such as fairings, are secondary orbital objects. They are often called satellites, although they move along near-Earth orbits and serve primarily as observation objects for scientific purposes.

From 1957 to 1962 The names 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 an Arabic numeral - the number of the object, depending on its scientific significance or brightness. But the number of satellites launched grew rapidly, therefore, from January 1, 1963, they began to be designated by the year of launch, the launch number in the same year and the letter of the Latin alphabet.

Satellites can be different in size, design, weight, and composition of on-board equipment, depending on the tasks performed. The equipment of almost all satellites is powered by solar panels installed on the outer part of the body.

AESs are launched into orbit using automatically controlled multistage launch vehicles. The movement of artificial Earth satellites is subject to passive (planetary attraction, resistance, etc.) and active (if forces are installed on the satellite.

Interesting facts about artificial satellites of the Earth attract the attention of almost every person, since this topic is very interesting. The space age began more than half a century ago, and during all this time a large amount of interesting information has accumulated.

The first satellite that went into extraterrestrial space was called PS-1 or the simplest satellite. It was put into orbit by a launch vehicle, launched from the USSR test site, now called Baikonur. This event marked the beginning of space exploration.
PS-1 weight approximately 83 kg. It looked like a ball with a diameter of 58 cm. It had four antennas about three meters long, they were used to transmit signals. At 315 seconds after launch, PS-1 issued its first call signs, which the whole world was eagerly awaiting.
The pioneer stayed in orbit for 92 days. During this time, he managed to cover 60 million km, which is equal to 1440 revolutions around the globe. Its radio transmitter was able to last two weeks after launch.
The creator of the pioneer Sergei Korolev could receive the Nobel Prize, but since in Soviet times everything was common, the achievement of the great scientist became “a victory for the entire Soviet people.” For nine long years it was not even known who could give the world such an achievement.
Thanks to the first IS, it was possible to study the surface layers of the ionosphere. He also helped to obtain information about the operating conditions of the equipment; they were very useful during the next launches of PS-1 followers.
Newspapers of that time wrote that the satellite could be seen in the sky without the use of special devices, but this was not the case. What everyone took for the PS-1 was the central block of the rocket. It weighed about seven tons, it was placed into orbit simultaneously with the satellite, or rather, it launched PS-1 there. The block “floated” in the sky until it burned out.
Today, approximately 13 thousand artificial satellites roam the expanses around the globe.. They are very useful because they “know how to do” many important things. Thanks to them, satellite phones can work anywhere on our planet, just like satellite navigation systems; ships come to port; Satellite TV works. Often, when viewing the map of the most famous search engines, we come across a “satellite view” tab, which makes it possible to see photos of any part of the planet from a great height.
The launch pattern is akin to throwing a stone. More precisely, the satellite needs to be thrown at such a speed that it can rotate around the planet on its own. The parameters for such an injection are: 8 km/s, and this must be done outside the atmosphere. Otherwise, friction with the air will become a hindrance. If everything works out, the satellite will live in low-Earth orbit, without outside help and without stopping.
In the early 2000s, a copy of PS-1 was sold at the famous eBay auction. According to some experts, during the Soviet era, about 20 identical models were created, on which testing and demonstration were carried out. The exact number of copies is still unknown, since the information was secret, but to this day many museums claim that their collections contain an analogue of the PS-1.
In the history of satellite launches, there was only one case of a satellite being destroyed by a meteorite.. It was registered in 1993. It was the European Space Agency's Olympus IP.
The first GPS satellite was launched in 1978..

Spacecraft in all their diversity are both the pride and concern of humanity. 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 in which they live from the outside, has taken us to a new level of development. A rocket in space today is not a dream, but a matter 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 is a general name for any device designed to operate in space. There are several options for their classification. In the simplest case, spacecraft are divided into manned and automatic. The former, in turn, are divided into spaceships and stations. Different in their capabilities and purpose, they are largely similar in structure and equipment used.

Flight Features

After launch, any spacecraft goes through three main stages: insertion into orbit, flight itself and landing. The first stage involves the device developing the speed necessary to enter outer space. In order to get into orbit, its value must be 7.9 km/s. Complete overcoming of gravity involves the development of a second equal to 11.2 km/s. This is exactly how a rocket moves in space when its target is remote areas of the Universe.

After liberation from attraction, the second stage follows. During an 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 that matches the tasks it is designed to solve. However, the main discrepancy is related to the so-called target equipment, which is necessary precisely for obtaining data and various scientific research. Otherwise, the equipment of the spacecraft is similar. It includes the following systems:

energy supply - most often solar or radioisotope batteries, chemical batteries, and 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 to constantly determine their own position in space;
movement - spacecraft engines allow changes in flight speed, as well as in its direction.

Classification

One of the main criteria for dividing spacecraft into types is the operating mode that determines their capabilities. Based on this feature, devices are distinguished:

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

Let's take a closer look at some types.

AES (artificial earth satellites)

The first devices launched into space were artificial Earth satellites. Physics and its laws make launching any such device into orbit a difficult task. Any device must overcome the gravity of the planet and then not fall on it. To do this, the satellite needs to move at or slightly faster. Above our planet, a conditional lower limit of the possible location of an artificial satellite is identified (passes at an altitude of 300 km). A closer placement will lead to a fairly rapid deceleration of the device 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. Thus, 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 altitudes. Naturally, the time required for one lap also depends on this. Satellites, whose orbital period is equal to a day, are placed on the so-called It is considered the most valuable, since the devices located on it appear motionless to an earthly observer, which means there is no need to create mechanisms for rotating antennas.

AMS (automatic interplanetary stations)

Scientists obtain a huge amount of information about various objects of the Solar System using spacecraft sent beyond the geocentric orbit. AMS objects are planets, asteroids, comets, and even galaxies accessible for observation. The tasks posed to 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

Devices created to deliver people to their intended destination and return them back are in no way inferior in technological terms to the described types. The Vostok-1, on which Yuri Gagarin made his flight, belongs to this type.

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

Spacecraft, like all astronautics, are constantly being improved. Recently, the media have often seen reports 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 vehicle motion, and so on. The landing of the Philae probe on the comet is considered an event comparable to Gagarin's flight. The most interesting thing is that this is not the crown of humanity’s capabilities. New discoveries and achievements still await us in terms of both space exploration and the structure

Artificial Earth satellites

Maintaining. Artificial Earth satellites are spacecraft launched into low-Earth orbits. The shape of satellite orbits depends on the speed of the satellite and its distance from the center of the Earth and is a circle or ellipse. In addition, the orbits differ in inclination relative to the equatorial plane, as well as in the direction of rotation. The shape of satellite orbits is affected by the nonsphericity of the Earth’s gravitational field, the gravitational fields of the Moon, the Sun and other celestial bodies, as well as aerodynamic forces arising when the satellite moves in the upper layers of the atmosphere, and other reasons.

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

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

Research AES are used 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 height of up to 500 thousand km. These are the satellites “Prognoz”, “Electron”, “Proton”, etc., launched into orbits to study the processes of solar activity and their influence on the Earth’s magnetosphere, study cosmic rays and the interaction of supersonic energy particles with matter.

TO applied AES include communications (telecommunications), meteorological, geodetic, navigation, oceanographic, geological, rescue and search and others.

Of particular importance are communications satellites- “Molniya” (Fig. 2.5), “Rainbow”, “Screen”, “Horizon”, designed for relaying television programs and providing long-distance radio communications. They use elliptical synchronous orbits with high eccentricity. For continuous communication with the region, you should have three such satellites. The Raduga, Ekran and Horizon satellites also have circular equatorial geostationary orbits with an altitude of 35,500 - 36,800 km, which provides round-the-clock communication through the Orbita network of ground-based receiving television stations.

All these satellites have dynamic stabilization relative to the Earth and the Sun, which allows them to reliably relay received signals, as well as orient solar panels (SB) towards the Sun.

Rice. 2.5. Diagram of the connected artificial Earth satellite "Molniya":

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 an altitude of 900 km. They record the state of the atmosphere and clouds, process the information received and transmit it to Earth (in one revolution, the satellite surveys up to 20% of the globe's area).

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

Navigational AESs of the “Cicada” and “Hurricane” types are designed for the global navigation satellite systems “GLONASS”, “Cosmos-1000” (Russia), “Navstar” (USA) - to provide navigation of sea vessels, aircraft and other moving objects. With the help of navigation and radio systems, a ship or aircraft can determine its position relative to several satellites (or at several points in the satellite’s orbit). For navigation satellites, polar orbits are preferable, because they cover the entire surface of the Earth.

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

Onboard equipment of satellites. The composition of the on-board equipment of the satellite is determined by the purpose of the satellite.

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

To process observation results and analyze them, complex information and 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 on-board radio systems operating in various radio frequency ranges. A radio complex may contain several antennas of various types and purposes (parabolic, spiral, whip, horn, etc.).

To control the movement of the 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 according to commands received from the ground control complex.

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

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

Satellite orientation system. Most satellites use an orientation system that ensures a fixed position of the axes relative 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 using microrocket engines or jet nozzles located on the surface of the satellite or protruding structures (panels, trusses, etc.). To stabilize artificial satellites in medium and high orbits, very low thrusts (0.01... 1 N) are required.

Design features. AESs are launched into orbit under special fairings that absorb all aerodynamic and thermal loads. Therefore, the shape of the satellite and design solutions are determined by functional feasibility and permissible dimensions. Typically, artificial satellites have monoblock, multiblock or truss structures. Some of the equipment is placed in thermostated sealed compartments.

Automatic interplanetary stations

Introduction. Automatic interplanetary stations (AIS) are designed for flights to the Moon and planets of the Solar system. Their features are determined by the large distance of operation from the Earth (up to leaving the sphere of action of its gravitational field) and the flight time (can be measured in years). All this places special demands on their design, control, power supply, etc.

The general view and typical layout of the AMS is shown using 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 - orbital vehicle; 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 AMS Luna-1 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 operated on the Moon. These achievements significantly outstripped American exploration of the Moon with automatic vehicles.

With the help of a series of space probes 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 the spacecraft flights, it was established that the pressure of the atmosphere of Venus is more than 9 MPa (90 atm), and the temperature is 475 ° C; a panorama of the planet's surface was obtained. This data was transmitted to Earth using a complex combined structure AMS, one of the parts of which descended to surface planet, and the second, launched into satellite orbit, received information and transmitted it to Earth. Similar complex studies were carried out on Mars. During these same years, a wealth of scientific information was received on Earth from the Zond spacecraft, on which many design solutions for subsequent spacecraft were worked out, including upon their return to Earth.

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

The flights of the American spacecraft “Ranger”, “Surveyor”, “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 probes reached the distant 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 successfully performing a braking maneuver:

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

AMS orbits. For spacecraft flights to the planets of the solar system, they must be given a speed close to the second cosmic speed or even exceeding it, and the orbit takes the shape 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 trajectory of an AWS can consist of several sections, the shape of which is determined by the laws of celestial mechanics.

On-board equipment of the AMS. On AWS intended for the study of planets, depending on the tasks being solved, a variety of instruments and devices are installed: television cameras with small and large viewing angles, cameras and photopolarimeters, ultraviolet spectrometers and infrared interferometers, magnetometers, detectors of cosmic rays and charged particles, measuring instruments plasma characteristics, telescopes, etc.

To carry out planned research, some scientific instruments can be located in the AWS housing, others are removed from the housing using trusses or rods, installed on scanning platforms, and rotated relative to their axes.

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

To provide the on-board control complex and instruments with electricity, solar panels or nuclear radioisotope thermoelectric generators (necessary for long-term flights to distant planets) can be used on the AWS.

Features of the AMS design. The supporting structure of the AMC usually has a lightweight truss frame (platform) on which all equipment, systems and compartments are mounted. For electronic and other equipment, sealed compartments with multi-layer thermal insulation and a thermal control system are used.

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

AMS can have an orbital maneuvering propulsion system to correct the trajectory or to transfer the AMS into the orbit of a planet or its satellite. In the latter case, the design of the AWS becomes significantly more complicated, because To land the station on the surface of planets, it requires braking. It is carried out using a braking propulsion system or due to the planet’s atmosphere (if its density is sufficient for braking, as on Venus). During braking and landing, significant loads arise on the structure and instruments, so the descent part is usually separated from the AMS, giving it appropriate strength and protecting it from heat and other loads.

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

The development of technological progress occurs at such a pace that the most outstanding scientific achievements quickly become commonplace and cease to amaze.

Space exploration was no exception. Almost 6 decades separate us from the launch of the first artificial Earth satellite (RS-1). Let's remember how it was. Let's find out how far science has advanced in this area.

How it was

By the mid-60s of the last century In the USSR, a powerful group of like-minded people was formed who were engaged in practical astronautics. Led the group.

It was decided to begin the first steps into space with the launch of an artificial Earth satellite. Wherein the following tasks were set:

checking all theoretical calculations;
collecting information about the operating conditions of the equipment;
study of the upper layers of the ionosphere and atmosphere.

To carry out the required amount of research The satellite, 58 cm in diameter, housed special equipment and power supplies. To maintain a constant temperature, its internal cavity was filled with nitrogen, which was driven by special fans. The total weight of the first spacecraft was 83.6 kg. Its sealed body was made of a special aluminum alloy, and the polished surface underwent special treatment.

Four rod antennas with a length of 2.4 to 2.9 m, installed on the outer surface of the satellite, were pressed against the body during the launch of the device into orbit.

How a missile range became a cosmodrome

To launch the RS-1 satellite it was it was decided to use a military training ground in the Kazakhstan desert. The decisive factor in choosing the location was its proximity to the equator. This made it possible to make maximum use of the Earth's rotation speed during launch. And its remoteness from Moscow made it possible to maintain a regime of secrecy.

It was at the Baikonur military training ground that the space gates first opened and the first artificial earth satellite was launched. "Sputnik-1" launched October 4, 1957 at 22:28 Moscow time. During 92 days of operation in low-Earth orbit, it completed about one and a half thousand revolutions around the Earth. For two weeks, his “beep-beep-beep” signals were received not only at the mission control center, but also by radio amateurs around the world.

How the satellite was delivered into orbit

To launch the first Soviet satellite it was used a two-stage intercontinental missile R-7, which was developed as a carrier for the hydrogen bomb.

After some modifications to its design and several tests, it became clear that it would cope with the task of launching a satellite into a given orbit.

The satellite was placed at the head of the rocket. Its launch was carried out strictly vertically. Then the rocket axis was gradually deviated from the vertical. When the rocket speed was close to the first escape velocity, the first stage separated. The further flight of the rocket was now ensured by the second stage, which increased its speed to 18-20 thousand km/h. When the rocket reached the highest point of its orbit, the satellite separated from the launch vehicle.

His further the movement occurred by inertia.

Physical basis of satellite flight

For a body to become an artificial satellite, two basic conditions must be met:

communicating to the body a horizontal speed of 7.8 km/sec (first cosmic speed) to overcome earth's gravity;
moving it from dense layers of the atmosphere to very rarefied ones that do not offer resistance to movement.

Having reached escape velocity, the satellite rotates around the planet in a circular orbit.

If its rotation period is 24 hours, then the satellite will rotate synchronously with the Earth, as if hovering over the same area of the planet. Such an orbit is called geostationary, and its radius, at a given speed of the device, should be six times the radius of the Earth. As the speed increases up to 11.2 km/sec, the orbit becomes increasingly elongated, turning into an ellipse. It was in this orbit that the first brainchild of Soviet cosmonautics moved. At the same time, the Earth was at one of the foci of this ellipse. The greatest distance of the satellite from the Earth was 900 km.

But in the process of movement, it still plunged into the upper layers of the atmosphere, slowed down, gradually approaching the Earth. In the end, due to air resistance it heated up and burned in the dense layers of the atmosphere.

60-year history of satellite launches

The launch and flight of this tiny silver ball at such a considerable distance from the Earth was a triumph of Soviet science for that period. This was followed by a number of more launches, which pursued mainly military purposes. They performed reconnaissance functions and were part of navigation and communications systems.

Modern workers of the starry sky perform a huge amount of work for the benefit of humanity. In addition to satellites intended for defense purposes, the following are in demand:

Communications satellites (repeaters), providing stable, weather-independent communications over a large area of the planet.
Navigation satellites, serving to determine the coordinates and speed of all types of transport and determine the exact time.
Satellites, allowing you to photograph areas of the earth's surface.“Space” photographs are in demand by many ground-based services (forestors, ecologists, meteorologists, etc.); they are used to create extremely accurate maps of any part of the planet.
The “scientist” satellites are platforms for testing new ideas and technologies, tools for obtaining unique scientific information.

The manufacture, launch and maintenance of spacecraft requires enormous expenses, so international projects began to appear. One of them INMASART system, providing ships on the high seas with stable communications. It was thanks to her that many ships and human lives were saved.

Look at the night sky

At night, among the diamond scattering of stars, you can see bright, non-blinking luminous points. If they, moving in a straight line, fly across the entire sky in 5-10 minutes, then you have seen a satellite. Only fairly large satellites, at least 600 m in length, can be observed with the naked eye. They are visible only when they reflect sunlight.

Such objects include international space station (ISS). You can see it twice in one night. It first moves from the southeastern part of the sky to the northeast. After about 8 hours, it appears in the northwest and disappears behind the southeastern part of the horizon. The best time to observe it is June–July - an hour after sunset and 40–60 minutes before the sunrise.

As you follow the luminous point with your gaze, remember how much effort and knowledge was invested in this miracle of technical thought, what courage the people working on board the orbital station have.

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