Iridium constellation

Iridium system is a global satellite communication system designed by Motorola. Its part in the sky is satellites running in seven orbits, and 1 1 satellites are evenly distributed in each orbit to form a complete constellation. They are called iridium satellites, just like the 77 electrons outside the iridium (Ir) core orbiting them. Later, after calculation, it was confirmed that six orbits were enough, so the total number of satellites was reduced to 66, but it was still used to being called iridium.

Iridium travels in an orbit 780 kilometers high, passing through the North and South Poles. In addition to 1 1 satellite, there are 1 ~ 2 spare stars in each orbit. These satellites can cover the whole world, and users can communicate directly with them by hand-held phones without a parabolic antenna with a diameter of several meters.

The Delta -2 rocket of the United States, the Proton -K rocket of the Russian Federation and the improved Long March -2-C rocket of China undertook the iridium launch mission respectively. /kloc-0 completed the satellite deployment task in May, 1998, and officially opened the global communication service on1October1day.

Iridium satellite system is the first generation satellite communication system proposed by the United States in 1987. Each iridium satellite has a mass of about 670kg and a power of 1200W, and adopts a three-axis stable structure. Each satellite has 3480 channels and its service life is 5-8 years. The biggest feature of "Iridium" system is to realize global communication through relay between satellites, which is equivalent to moving the terrestrial cellular mobile phone system to the sky.

After the completion of the iridium satellite system, it can continuously cover every corner of the earth's surface. No matter at sea, on land or in the air, users can always take out their "mobile phones" from their pockets to make phone calls. Compared with the current geostationary satellite communication system, it has two advantages: first, low orbit, fast transmission speed, small information loss and greatly improved communication quality; Second, the "Iridium" system does not need a special ground receiving station, and each mobile phone can communicate directly with the satellite, making the inaccessible barren land, remote areas with backward communication and natural disaster sites on the earth unimpeded.

Therefore, "Iridium" system started a new era of personal satellite communication.