Artificial satellite

In the history of the greatest scientific and technical achievements, the event that took place on October 4, 1957, occupies a special place. On this day, the first artificial satellite Earth and humanity entered a new era - the era of the exploration and use of outer space. With all the grandiosity of the subsequent achievements of astronautics, none of them has, as everyone admitted, had such a huge impact on the minds and feelings of people in all parts of the world, like the launch of the "simplest artificial satellite", as the creators themselves called it.

October 4, 1957 - on this day was launched the first artificial Earth satellite

But launching an artificial satellite is not only the creation of an apparatus capable of operating in space flight conditions. This is the development and construction of a huge rocket and space complex. Priority in its creation belongs to S.P. Korolev, M.V. Keldysh, V.P. Glushko, M.K. Yangel, V.N. Chelomey, N.A. Pilugin and many other outstanding scientists and designers. At the present time, cosmonautics is increasingly acquiring an international character. Dozens of countries participate in space programs.

The artificial satellite is irreplaceable for scientific and economic activities. Artificial satellites explore Earth and distant planets, serve geologists, workers in agriculture, provide communication and find people in distress, help create new materials and medicines.

To move in orbit around the earth, an artificial satellite must have an initial velocity equal to or greater than the first cosmic velocity. Flights are performed at altitudes of up to several hundred thousand kilometers. The lower limit of the altitude of the flight makes it necessary to avoid the process of rapid braking in the atmosphere. The period of revolution of an artificial satellite in orbit, depending on the average altitude of the flight can be from one and a half hours to several years. Of particular importance are satellites in the geostationary orbit, whose circulation period is strictly equal to the day, and therefore for the terrestrial observer they are immovably "hanging" in the sky, which allows you to get rid of rotary devices in satellite antennas.

Unmanned artificial satellites have masses from several kilograms to two dozen tons and dimensions from several centimeters to (in particular, using solar cells and pull-out antennas) of several tens of meters.