Starlink is a satellite constellation being constructed by American company SpaceX to provide satellite Internet access. The constellation will consist of thousands of mass-produced small satellites, working in combination with ground transceivers.
SpaceX intends to provide broadband internet connectivity to under served areas of the planet, as well as provide competitively priced service to urban areas. The company has stated that the positive cashflow from selling satellite internet services would be necessary to fund their Mars plans. The satellites will be mass-produced, at a much lower cost per unit of capability than existing satellites. Musk said, "We’re going to try and do for satellites what we’ve done for rockets.
Internet traffic via a geostationary satellite has a minimum theoretical round-trip latency of at least 477 ms (between user and ground gateway), but in practice, current satellites have latencies of 600 ms or more. Starlink satellites would orbit at 1⁄30 to 1⁄105 of the height of geostationary orbits, and thus offer more practical Earth-to-sat latencies of around 25 to 35 ms, comparable to existing cable and fiber networks. The system will use a peer-to-peer protocol claimed to be "simpler than IPv6", it will also incorporate end-to-end encryption natively.
The system will not compete with the Iridium satellite constellation, which is designed to link directly to handsets. Instead, it will be linked to flat user terminals the size of a pizza box, which will have phased array antennas and track the satellites. The terminals can be mounted anywhere, as long as they can see the sky.
Expected life of the satellites is around 5 years and the newest ones will quickly burn in Earth's atmosphere at the end of each satellite's lifecycle. The large number of planned satellites have been met with criticism from the astronomical community. Astronomers claim that the number of visible satellites will outnumber visible stars, and that their brightness in both optical and radio wavelengths will severely impact scientific observations. The most recent launch in January 2020 though has experimented with darker colour to minimise reflection of light.
Extracted from https://en.wikipedia.org/wiki/Starlink_(satellite_constellation)