A satellite internet constellation is a constellation of artificial satellites providing satellite internet service. In particular, the term has come to refer to a new generation of very large constellations (sometimes referred to as a megaconstellations) orbiting in low Earth orbit (LEO) to provide low-latency, high bandwidth (broadband) internet service.
While more-limited satellite internet services have been available through geosynchronous commsats orbiting in geostationary orbit for years, these have been of quite limited bandwidth (not broadband), high-latency, and provided at such a relatively high price that demand for the services offered has been quite low.
In the 1990s, several LEO satellite internet constellations were proposed and developed, including Celestri (63 satellites) and Teledesic (initially 840, later 288 satellites). These projects were abandoned after the bankruptcy of the Iridium and Globalstar satellite phone constellations in the early 00's.
In the 2010s, interest in satellite internet constellations reemerged due to the dropping cost of launching to space and the increased demand for broadband internet access. Internet satellite constellations are planned by private companies like OneWeb (OneWeb constellation), SpaceX (Starlink), Amazon (Project Kuiper), Samsung, Boeing and Russia's Roscosmos (Sfera) and China (Hongwan, 2018, or national satellite internet project, 2021).. By late 2018, more than 18,000 new satellites had been proposed to be launched and placed in LEO orbits between 2019 and 2025. This is more than ten times as many satellites as the sum of all active satellites in space as of March 2018. More recent proposals by 2020 could bring that number to over 100,000.
A year after the start of fielding the first satellite internet constellation—Starlink which began launching in late 2019 and began beta test of the network in late 2020; OneWeb began satellite deployment in 1H2020—the competitive disruption to established satellite company business models began to be better understood. In early 2021, the three largest European satellite operators SES, Eutelsat, and Hispasat—which had until that time eschewed developing and fielding a broadband satellite internet constellation with private funds—informed the European Commission that they would be willing invest in the development of such a project if the European Union were to invest government funds in the effort as well. All three companies had formerly focused on the provision of communication services from GEO and MEO orbits, while the newer satellite internet providers have been fielding their constellations exclusively in LEO.
Proposed systems vary greatly in the number of satellites, the types of orbits and the telecommunication architecture (in particular the presence or absence of inter-satellite links). System designs have been analyzed using statistical methods and simulations to estimate the total throughput. Particularly challenging is the dynamic nature of the network, as LEO satellites typically pass over a given location in less than 10 minutes.
For continental distances (greater than about 3,000 km), LEO satellite internet networks are expected to be able to provide lower latency than optical fiber links. This is expected to hold even without inter-satellite links, using only ground station relays. The new networks are said to be able to "potentially compete with today's ISPs in many settings".
Critics have objected against the increased light pollution for astronomy and the increased possibility satellite collisions resulting in space debris. Astronomers have studied the potential effects increased satellite usage in Low Earth Orbit would have on very large telescope that use ultra-wide imaging exposures, such as the 8.4-meter Simonyi Survey Telescope used in the Legacy Survey of Space and Time project at the Vera C. Rubin Observatory. They found that 30 to 40% of exposures could be compromised during the first and last hours of the night.
The most visible or at least, the most talked about LEO contenders stem from the U.S. and Canada, numbering at least 11 with planned satellites to be deployed at around 18,000.
Satellite latency is 638ms, 20 times higher than terrestrial broadband.