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 man in the street. Even in remote areas, it is now possible to watch TV shows and use Internet services, 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 ability to receive high-quality television signals is provided by the Federal State Unitary Enterprise "Space Communications". It is one of the ten largest satellite operators in the world, with its own TV program compression center. In addition, it provides multiplexing of digital streams, forms packages of federal programs for television and radio broadcasting.
Space component
The enterprise consists of an orbitalconstellation of 12 satellites of all bands. 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. Orbital location of spacecraft on the arc of the orbit - from longitude 14° West to longitude 145° East.
Earth component
The infrastructure that is on earth is the five space communication centers. They are located throughout Russia. In its activities, the enterprise is guided by the Federal Target Program for the Development of Television and Radio Broadcasting in the Russian Federation for 2009-2018. The range of services provided is very wide:
- management, 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 communications;
- trunk and maritime communications.
Space communication systems
Transmission of information through the Earth-space satellite channel and back is carried out in various ways. Telemetry, telephone, telegraph and television systems are used in space. The most popular radio communication system. The main distinguishing features of space communication with flying space objects are as follows:
- the ever-changing position of spacecraft;
- continuous change in the frequency of the signal at the reception;
- limited line-of-sight withground points of contact;
- limiting the power of transmitters located on spacecraft;
- huge communication range.
Development of space communications
Everyone knows that the first communication with a man in space took place on April 12, 1961. The cosmonaut was Yuri Gagarin, throughout his entire flight, stable two-way telephone and telegraph communication was maintained between the Earth and the Vostok spacecraft in the range of meter and decameter waves.
In the future, space communication with the earth improved, and already in August 1961, during the flight of cosmonaut G. S. Titov appeared with a television image reduced to 10 frames per second. Today, television systems of the usual standard 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. A single orbiting satellite costs up to $230 million, and the owner's task is to launch and use it effectively as a rental object. There are only two large corporations in Russia that can afford to have a satellite in geostationary orbit - FSUE Kosmicheskaya Svyaz and OAO Gazprom Space Systems.
Short Wave Problems
Radio communication with space objects and aircraft located at distances of more than 1,000 kilometers is carried out in the shortwave range. But inin the modern world, this range is no longer enough. The reasons for this situation are as follows:
- about a thousand radio stations can operate in the shortwave range without significant interference, and there are many more of them today.
- Increasing levels of interference require more powerful transmitters.
- The fundamental defect of such a 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 long distances.
Ultra-short wave band is less crowded, but reception is only in the line of sight.
Exit - satellites
It is the presence of a signal repeater in space, namely on satellites, that gives 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. Satellites can be equipped with active and passive signal repeaters, and the satellites themselves can be both stationary (stationary relative to the Earth) and flying in low orbits.
