Artificial satellites of the Earth are flyingspacecraft that are launched into Earth orbit and rotate around it in a geocentric orbit. They are intended for solving applied and scientific problems. For the first time the launch of an artificial satellite of the Earth took place on October 4, 1957 in the USSR. It was the first artificial celestial body that humans created. The event became possible due to the results of achievements in many areas of rocket, 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, check the accuracy of theoretical calculations and the main technical solutions that were used to put the satellite into orbit, and study the features of radio transmission in the ionosphere.
America launched its first satellite "Explorer-1" 1February 1958, and then, a little later, other countries also launched launches: France, Australia, Japan, the People's Republic of China, the United Kingdom. In the field of space research, collaboration among countries around the world has become widespread.
The spacecraft may be called a satelliteonly after making more than one revolution around the Earth. Otherwise, it is not registered as a satellite and will be referred to as a rocket probe, which carried out measurements along a ballistic trajectory.
The satellite is considered active if on itradio transmitters, flash tubes, light signals, measuring equipment are installed. Passive artificial satellites of the Earth are often used for observations from the surface of the planet in the performance of certain scientific tasks. These include satellite balloons with a diameter of up to several tens of meters.
Artificial satellites of the Earth are divided intoapplied and research, depending on the tasks they perform. Research designed to conduct studies of celestial bodies, the Earth, outer space. These are geodetic and geophysical satellites, astronomical orbital observatories, etc. Applied satellites are communication satellites, navigation satellites, meteorological satellites for research of the Earth’s resources, technical satellites, etc.
Artificial Earth satellites created forhuman flight, are called "manned spacecraft satellites." AES in a polar or polar orbit is called polar, and in an equatorial orbit - equatorial. Stationary satellites are satellites launched into an equatorial circular orbit, the direction of motion of which coincides with the rotation of the Earth, they still hang over a specific point on the planet. Separated from the satellites when entering into orbit parts, such as, for example, head fairings, are secondary orbital objects. Often they are called satellites, although they move along near-Earth orbits, and serve primarily as objects for observation for scientific purposes.
From 1957 to 1962The 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 the Arabic numeral - the number of the object depending on its scientific significance or brightness. But the number of launched satellites has rapidly increased, because from January 1, 1963, they began to be designated as the launch year, launch number in the same year, and the letter of the Latin alphabet.
Спутники могут быть различными по размерам, design schemes, weight, 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 mounted on the outer part of the body.
The satellites are injected into orbit usingautomatically multi-stage launch vehicles. The movement of artificial satellites of the Earth is subject to passive (gravity of the planets, resistance of the Earth’s atmosphere, etc.) and active (if a jet engine is installed on the satellite) forces.
