How Does Satellite Internet Work?

Satellite internet is unique among connection types because, in theory, it can work just about anywhere in the world without the need to build infrastructure on the ground. Other wireless technologies, like 5G, need powerful transmitters within range of your house for you to connect. Not so with satellite. All you need is a clear view of the sky.

Of course, it’s a bit more complicated than this, so we’ll walk you through the weird and wonderful world of satellite internet.

Satellite infrastructure

In order for a satellite internet customer to connect to the rest of the internet, they need three things: a ground station, a satellite, and an antenna. On the one hand, that’s a lot fewer steps than all the amplifiers, terminals, and hubs (not to mention hundreds of miles of physical cables) used for a wired connection like fiber, but the first two steps are pretty big ones.

Ground stations

Telecommunications ports, more commonly known as teleports or ground stations, are the end of the satellite network that connects to the rest of the internet. These are typically huge installations with massive dishes that the satellite provider builds directly onto an internet backbone. All that provider’s internet traffic in the area (or even an entire continent) passes through that one point, so it has to be built to handle a huge bandwidth.

Satellites

The key part of a satellite network is the satellites. They are the part that connects the customer with the provider, and they’re also the hardest part to fix if there’s a problem.

Communication satellites can operate anywhere from low-Earth orbit to high geosynchronous orbits. This distance causes satellite internet to have incredibly high latency compared to other types of internet connections, as all the data has to travel from the ground station to the satellite, then from the satellite to your home. It also means that lots of atmospheric conditions can interfere with your satellite signal.

Antennas

The other end of a satellite network is the customer’s antenna, also referred to as a user terminal or a satellite dish. These antennas often have a large dish-shaped reflector that focuses the satellite signal onto a small receiver, kind of like using a magnifying glass to focus sunlight. That receiver then sends the signal down a cable to your modem and router, which then connects with the devices in your house.

Along with the receiver, your antenna also has a transmitter, since navigating the internet requires both sending and receiving data.

The only thing that the antenna needs to function is electricity to power the equipment and an unobstructed view of the sky where the satellite it’s connected to is located. For customers in the U.S., this usually means the southern sky, but that depends a bit on the type of satellites your provider operates.

LEO vs. MEO vs. GSO satellites

Communication satellites differ depending on the altitude of their orbit. Originally, communication satellites were all huge spacecraft in high orbits, but recent technological advances have made constellations of hundreds or thousands of smaller satellites in lower orbits possible.

LEO satellites

The development of low-Earth orbit (LEO) internet satellites began with Starlink, which was announced in 2015. Since then, other providers have tossed their hat in the ring, including OneWeb, Telesat, and Amazon Leo, drastically transforming the way that people connect to the internet in rural areas.

LEO satellites fly around the Earth just outside the atmosphere. This tight orbit means that they orbit much faster than the planet rotates, so if viewed from the ground, they seem to move across the sky quickly. They’re also visible to a much smaller area than satellites in higher orbits. This means that to provide coverage to a single area, you have to have at least one satellite coming into view before the previous one leaves. That’s why LEO constellations require a huge number of satellites.

Their satellites’ low orbits also mean that LEO providers can’t just use one big ground teleport for the entire constellation. Ground stations have to be placed so that the customer’s antenna can see a satellite and that satellite can see a ground station at any given time. Some providers, like Starlink, have developed laser interlinks between satellites so that, if it can’t find an available ground station, it can route its transmission through nearby satellites until it finds one that can.

The advantages of LEO satellites are their low latency and low cost. Since they’re much closer to the Earth’s surface, they only have a fraction of the latency of other satellites. Since they don’t have to go as high, they require less fuel to launch. And because they don’t cover as much area, they don’t have to be as big. This means that in theory, they can be designed to have much shorter operational lives and can be moved to burn up in the atmosphere at the end of their lifecycle.

MEO satellites

Medium-Earth orbit (MEO) satellites operate at higher ranges than LEO satellites, and as such tend to be larger spacecraft that require a much bigger investment. Medium-Earth orbit is the range in which you will find the Global Positioning System and other navigational satellites.

MEO satellites are not as useful for telecommunications as LEO or GSO satellites, but they can be useful supplements for LEO constellations, such as by providing coverage for polar regions, providing high-throughput connections, or providing backhaul to satellites in lower orbits.

GSO Satellites

Geosynchronous orbit (GSO) satellites make a wide enough orbit that it takes them a full day to go around the Earth. Since they’re synced up with the Earth’s rotation, they are always visible from the same spot on the Earth’s surface.

The most important subsets of geosynchronous orbits are the geostationary orbits (GEO). GEO satellites are placed directly above the equator, so they never appear to move in the sky. This means that antennas can be pointed directly at the satellite and never have to move or track the satellite’s position. GSO satellites not aligned with the equator will appear to drift north and south or make figure-eights in the sky, but always returning to the same starting position.

GSO satellites orbit at an altitude of 22,236 miles. That’s so far from the Earth’s surface that they can basically see the entire half of the planet facing them. Since it takes so much fuel to launch a satellite to geosynchronous orbit, it makes sense to launch just a few large, powerful satellites that can provide coverage to entire continents. Traditional satellite internet providers like Viasat operate these kinds of satellites.

The biggest downside of GSO satellite internet is the high latency caused by transmitting across such massive distances. GSO satellites are also a huge investment, so it can be disastrous when something goes wrong. Any object in geosynchronous orbit is pretty much there forever, but satellites at the end of their lives will often boost out of the way to make room for new satellites, moving into a “graveyard” orbit.

How data navigates a satellite network

Sending and receiving data across a satellite internet connection works just about the same as on other internet connections, but with a few extra steps. When you type in a URL, that data goes to the transmitter on your antenna that will transmit the data to the satellite in orbit.

The satellite receives your uplink, along with uplinks from hundreds or thousands of other satellite customers. It keeps track of where it came from, then sends the data down to the teleport on the ground. At this point, your data joins the wider internet and travels to the appropriate DNS and web servers to find the page you were looking for.

When your data arrives at the teleport, it sends it back to the satellite, which will then use its antennas to target your location below. The satellite then transmits the data to your antenna, which receives the downlink, sends the information to your modem and router, which in turn sends data on to your computer.

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