Today, no one is surprised by the many satellite dishes on the roofs of residential buildings. Space communication has firmly entered the life of an ordinary layman. Even in remote areas there is now the opportunity to watch TV shows and use the Internet, while having a high signal level. But all this became possible thanks to the work of space communication centers, which will be discussed in this article.
World Wide Web
In the modern world, the network encircles the whole world. In Russia, the opportunity to receive high-quality television signals is provided by the Federal State Unitary Enterprise "Space Communication". It is one of the ten largest satellite operators in the world, with its own television compression center. In addition, it provides multiplexing of digital streams, forms packages of federal television and radio broadcasting programs.
Space component
The enterprise consists of an orbital constellation of 12 satellites of all ranges. The satellite service area is the entire territory of Russia, the CIS, Europe, Africa and the Middle East, Australia, North and South America, as well as the Asia-Pacific region. The orbital location of spacecraft on an orbit arc is from 14 ° west longitude to 145 ° east longitude.
Earth component
The infrastructure that is on the earth is the five centers of space communications. They are located throughout Russia. In its activities, the company is guided by the Federal Target Program for the Development of Broadcasting in the Russian Federation for 2009-2018. The range of services is very wide:
- control, space communications and monitoring of space structures and vehicles;
- communications and broadcasting (television and radio broadcasting, digital and satellite television) for 52 countries;
- government and presidential relations;
- trunk and maritime communications.
Space communication systems
The transmission of information on the Earth - space satellite channel and vice versa is carried out in various ways. In space, telemetry, telephone, telegraph, and television systems are used. The most popular radio communication system. The main distinguishing features of space communications with spacecraft are as follows:
- the ever-changing position of spacecraft;
- continuous change in signal frequency at reception;
- limited line of sight with ground-based points of contact;
- power limitations of transmitters located on spacecraft;
- huge communication range.
Space communication development
Everyone knows that the first connection with man in space took place on April 12, 1961. Yuri Gagarin was an astronaut. Throughout his flight, a stable two - way telephone and telegraph communication was maintained between the Earth and the Vostok spacecraft in the range of meter and decameter waves.
Subsequently, the space communication with the earth was improved, and already in August 1961, during the flight of the astronaut G.S. Titova appeared with a television image reduced to 10 frames per second. Today, conventional standard television systems are used, and the communication range reaches 350 million kilometers (when flying to Mars).
Technological and economic component
The lifetime of a satellite in orbit is about 15 years. During this time, the development of new communication technologies. One satellite with orbiting costs up to $ 230 million, and the owner’s task is to launch and use it effectively as a leased object. In Russia, there are only two large corporations that can afford to have a satellite in geostationary orbit - the Federal State Unitary Enterprise “Cosmic Communication” and OJSC “Gazprom Space Systems”.
Shortwave Issues
Radio communication with space objects and aircraft located at distances of more than 1,000 kilometers is in the short-wave range. But in the modern world this range is no longer enough. The reasons for this situation are as follows:
- In the short-wave range, about a thousand radio stations can operate without significant interference, and there are many times more of them today.
- An ever-increasing level of interference requires the use of more powerful transmitters.
- The principal defect of this range is the multipath propagation of waves and the effect of signal fading at the receiving point. This makes it almost impossible to communicate in this range of not very large distances.
The ultrashort wavelength range is less busy, but reception is only in sight.
Exit - satellites
It is the presence of a signal repeater in space, namely on satellites, that provides prospects and opens up new opportunities for the development of space communications. It will be able to provide reliable communication with distant objects in space and cover the surface of the planet with a reliable radio and television backbone grid. Active and passive signal transponders can be installed on satellites, and the satellites themselves can be either stationary (motionless relative to the Earth) or flying in low orbits.