Starlink in simple terms: how SpaceX’s satellite internet works

Thanks to Starlink, you can stay connected anywhere. All you need is the terminal itself, a power source for it, and an unobstructed view of the sky. 

However, far from everyone knows exactly how this technology works, where the internet comes from, and how our devices connect to it. So now we will explain in simple terms how the Starlink system is designed and what helps it provide connectivity in the most remote places.

What does the Starlink system consist of?

To understand how the Starlink system works, let's first look at what it consists of:

1. Low-Earth orbit satellites

2. Ground stations 

3. Subscriber terminals

Each of them performs its function, without which there would be no stable internet. 

1. Low-Earth orbit satellite constellation

Satellite internet has existed for decades, or more precisely—30 years. The first one in 1996 was the DirecPC service from Hughes Network Systems, created for consumers and small businesses. And at first, geostationary satellites (GEO) were used for its operation, which are located at an altitude of approximately 36,000 km from Earth. They move synchronously with the planet's rotation, so they appear stationary relative to a certain point on its surface. The main drawback of this technology is the great distance the signal has to travel between Earth and the satellite. Because of this, there is a significant data transmission delay.

Starlink works on a completely new principle thanks to the use of so-called LEO satellites, which are placed in low Earth orbit. And that is at an altitude of approximately 480 to 550 km above Earth. This is roughly like comparing the distance from Kyiv to Lviv with the length of the entire Earth's equator. Thanks to such a small distance, the radio signal travels in a few milliseconds. As a result—the signal delay becomes minimal, and the data loading speed—high. 

Another feature of Starlink satellites is their speed. They orbit the Earth at a speed of approximately 27,000 km/h. So that the internet remains available, while one satellite, for example, goes out of order, the terminal automatically switches to another. That is why Starlink uses a large number of satellites, which together form a whole constellation (currently over 11,000 devices) and provide coverage in different parts of the planet.

In addition to communication with Earth, some Starlink satellites are equipped with laser communication systems. They allow data to be transmitted directly between satellites that are in orbit. Thanks to this, information can move through the satellite network, even if there is no ground station nearby. This approach helps provide connectivity in remote areas and over oceans.

2. Ground stations 

Despite the fact that Starlink uses a satellite constellation, the ground infrastructure is also important for the system's operation. Its foundation is ground stations (gateways)—special facilities with antennas that provide data exchange between Starlink satellites and the ground internet infrastructure.

3. Subscriber terminal (customer equipment)

And finally, the third component of the system is the subscriber equipment, or Starlink terminals. This is what we see on the roofs of houses, cars (of course, in a protective Adaptis case), in field conditions, and during travel. These are devices that provide connectivity between the user and the satellite network.

The main part of the terminal is a phased array antenna. It receives the signal from Starlink satellites and transmits data from the user to them. Unlike regular satellite antennas, which need to mechanically turn towards the satellite, the Starlink terminal can electronically change the direction of the signal. Thanks to this, it maintains connectivity with satellites that are constantly moving above Earth.

The terminal converts the received signal into an internet connection, which becomes available to smartphones, laptops, and other devices via Wi-Fi.

But for the terminal itself to work, a Wi-Fi router is also needed. It provides the connection of smartphones, laptops, and other devices to the Starlink internet and distributes the connection between them. 

In practically all Starlink models, the router comes in the kit. The only exception is Starlink Mini, which is created to be more mobile, because the Wi-Fi router is already built directly into the terminal's body. At the same time, there is Starlink Mini X—a model with the same Mini terminal, but with an additional external router in the kit.

How does it all work together?

Imagine that you open a website on a smartphone connected to the Starlink network. For the page to load, your request must go through several stages.

First, the smartphone transmits the request via Wi-Fi to the router, and from there it reaches the Starlink terminal. The terminal's antenna transmits the data to the satellite with which communication is established at this moment.

Next, the satellite directs the information to the ground station. If there is no direct connection with it, the data can pass through other satellites using laser channels. The ground station transmits the request to the ground internet infrastructure, from where it reaches the server where the required website is hosted.

The server processes the request and sends the response back. It passes through the ground infrastructure, the satellite network, and the Starlink terminal, and then through the router reaches your smartphone.

At the same time, the Download speed (loading to you) is usually significantly higher than the Upload (sending from you), because watching videos or websites requires much more traffic than sending a regular request.

And all this happens in a few milliseconds, so for us, regular users, the entire data transmission process is completely imperceptible.