INTERNET From The Sky

Unbounded by traditional ground infrastructure, satellite internet delivers broadband internet to places where access has been unreliable or completely unavailable. All that is needed is a small satellite dish to receive the signal and pass the bandwidth on to your router. A new space race is on and this time it is all about the internet

- DR DEEPAK HALAN

Space based internet systems have been in use since last many years, facilitated by geostationary satellites at a staggering 35,786km height above the equator that zip at about 11,000km per hour. Signals beamed from the satellites cover about one-third of the Earth's surface; hence three to four satellites can cover the entire planet.

However, a significant time lag, called latency, of about 600 milliseconds occurs between seeking the data and receiving it. Satellite internet using lower Earth orbit (LEO) satellites reduces the latency to 20-30 milliseconds, which is close to that of terrestrial systems.

To go around the Earth every few hours and balance the effect of gravity, the speed of LEO satellites should be more than double the speed of geostationary satellites, as a result their visibility at any location is reduced and many satellites are needed to cover the complete surface of Earth. Starlink is expected to deploy as many as 42,000 satellites at altitudes of 350km to 1,200km.

The satellite internet provides consistent signals with high speed and low latency to preclude annoyances, such as dropped calls and lost or delayed signals. Satellite internet is most suitable for areas where it is not feasible or viable to lay cables or set up transmission towers due to inaccessible terrain and high costs.

How satellite internet works

Satellite internet connections are provided by an array of interlinked small sized satellites moving in LEO. This array beams the internet signals down to transreceivers located on ground.