The Starlink satellite constellation, operational since 2019, is based on unique technology allowing unparalleled connectivity across the entire planet. This technology is the laser.
The Starlink project, which has just been expanded with new satellites specially designed for connecting smartphones, is one of the most ambitious projects in recent years. Every day, 42 petabytes of data are transmitted from the satellite constellation to users. By making a small comparison, this volume of data represents 28 million hours of Full HD videos or 820 billion 50 KB Word documents. A technical feat made possible in part thanks to the precision of the laser.
Transmission technology
Satellites use radio frequencies on the KU (television) and KA (satellite broadband) radio bands to ensure transmissions to terrestrial relays. The latter operates between 26.5 and 40 GHz. The concern is that this band is very sensitive to weather conditions and can also experience disruption due to the presence of other frequencies.
This was without counting the innovation of SpaceX in 2021, which introduced laser communication systems between its different satellites. This set of lasers forms an immense mesh made up of 9,000 beams which therefore allow for smoother transmission of data (5.6 terabits per second transmitted daily). Even if the link to terrestrial relays is still done in the traditional way, the latency time is still considerably reduced.
Optimization and performance
In addition, these laser connections are constantly repositioned in order to maintain optimal transmission rate. Every day, the entire system reconfigures itself 266,141 times, or a little more than three times per second. The latter can thus continually adapt and readjust in order to maintain its effectiveness.
Certain laser connections, when they are efficient, can therefore be maintained for several weeks. Thus, satellites are able to maintain continuous and very stable communication over long periods without being interrupted. The more stable this link is, the more the integrity of the satellite network is ensured, which allows a satisfactory quality of service for users. Network losses will soon be just a bad memory in a few years!
Source : Futura Sciences
1