In the 1990s, there were already initial realizations for a satellite Internet using satellites in a wide variety of orbits. In some of these concepts, predominantly those using GEO satell ites and MEO satellites, the latency caused by the transit times from the ground station to the satellite and back again impair Internet services such as Internet telephony to such an extent that they cannot be used for such services.
To achieve global coverage of the Internet via satellites and also to be able to use services that are sensitive to delay times, LEO satellites, which orbit the Earth at altitudes between 500 km and 1,500 km at a speed of around 36,000 km/h in low orbits, are the obvious choice. The Starlink satellites initially have a flight altitude of 400 km to 650 km. These LEO satellites can be used to provide voice services, as well as data services, multimedia services and video services.
LEO satellites have only a small footprint due to their low orbit, which is why hundreds or even thousands of LEO satellites are needed to cover a large part of the earth. The concept of LEO satellites is being pursued in Starlink, a global satellite network initiated by the U.S. space company SpaceX. According to plans, Starlink wants 1,500 satellites in the first expansion stage. The following expansion stage envisions 2,800 satellites in orbits between 1,100 km and 1,325 km. Another 30,000 satellites are planned in low orbits between 300 km and 600 km. In total, the 42,000 Starlink satellites are distributed over more than 20 orbital planes. To ensure that regional areas are continuously supplied with the Internet, the satellites pass their data on to other satellites via Inter Satellite Links( ISL). The ISL link uses laser light beams.
Starlink is designed as a high-speed Internet and is intended to provide each user with a data transfer rate of 430 Mbit/s.