What is a satellite constellation after all? How many satellites do you need to have in orbit to go into the “constellation” category? can we consider GEO operators that have tens of satellites as constellation operators?
The term constellation was first used in the 90s with the first projects to launch many satellites to provide a global service, espcecially in telecoms. Projects like Iridium with 77 sats (66 now), Globalstar with 48 birds or Orbcomm with 36 small satellites are the projects that were launched. But there were many others, more ambitious, like Teledesic with hundreds of satellites planned for satellite Internet. Alas, the economics were not there at the time, especially on the supply side, with expensive infrastructure costs (satellites and launches). Either capital was not available to achieve the projects or the projects that successfully launched went for bankrupcy.
But listen to our friend Bob: times are changing and here come the 2000s with NewSpace…
To get back to our definition, if you check Wikipedia, a constellation is “is a group of artificial satellites working together as a system“: immediately, that disqualifies GEO satellites that always (or most of the time) work as single entities. So constellations are always LEO systems were satellites are organized to work together to provide the expected qiuality of service. Now the question is: how many satellites do you need to make a constellation?
This is a tricky one! Obviously, 2 or 3 satellites do not make a constellation. In my opinion, it should start at around 20 satellites which is the size of the GPS system. And go up to several thousands, which are the megaconstellations. The table below gives an overview of some of the constellations, in operations or as project… It gives an overview of the systems and the most credible projects. When dates contain “-“, these are non-yet fully operational systems. Systems like Spire and Planet are specific as they rely on unorganized constellations with no specific number of satellites to deliver the service.. To be noted: the very first constellations (GPS…) took a looong time to deploy: this process has accelerated over time and now companies are much faster (especially Starlink!)
| Deployment | Project | Size |
|---|---|---|
| 1998 | Iridium | 66 |
| 1995-1999 | Orbcomm | 36 |
| 1998-2000 | Globalstar | 48 |
| 1978-1993 | GPS | 24 |
| 2011-1028 | Galileo | 24 |
| 2012-2018 | Beidou | 24 |
| 1982-1995 | Glonass | 24 |
| 2013-2019 | O3B | 20 |
| 2015- | OneWEB | 880 |
| 2019- | Starlink | 12000-42000 |
| - | Kuiper | 3236 |
| - | Telesat | 120 |
| - | Hongyan/Hongyun | 320 |
| 2018- | Astrocast | 100 |
| - | Kineis | 25 |
| 2018- | Hiber | 48 |
| 2018- | Fleet | 100 |
| 2018- | Swarm | 150 |
| 2013- | Planet | 200+ launched |
| 2014- | Spire | 150 launched |
| 2018- | Kepler | 150 |