How Satellite Internet Works

Think about having high speed internet at the ocean centre.

Or video conferencing on some far-off Himalayan village where a fiber cable has never been installed.

Internet connectivity had over decades relied on underground cables, cell towers and huge fiber networks spanning continents. Unless the infrastructure was in place on the ground, there was no connectivity.

Internet via satellite is transforming that pattern. Companies are no longer depending on terrestrial cables to the fullest, but are constructing clouds of giant numbers of satellites in space, making space a layer of communications over the globe. It is not just the internet beneath our feet but it is above our heads.

But how does it actually work?

The Basic Idea: How Satellite Internet Actually Moves Data

Majority of the current web traffic is carried out via fiber optic cables buried on land and on the ocean floor. Actually, over 95 percent of transcontinental information moves by way of undersea cables. These fiber networks transport information in pulse of light at very high speeds.

Another factor that contributes to this system is satellite internet. Satellite networks are used to relay data in space-based networks in place of using ground-based infrastructure totally. The signal has a different path: When a user is connected to satellite internet the signal takes another path:

User terminal (dish) → Satellite in orbit → Ground station → Internet backbone → Back to user

The following is how it works in practice:

1. The satellite dish of a user emits a radio wave upwards.
2. The signal is received by a satellite in orbit around the earth.
3. The satellite transmits the signal to a ground gateway station which is linked to the ground fiber networks.
4. The requested information is transmitted in the reverse chain.

Inter-satellite laser links are used in some more recent satellites, such as SpaceX with the Starlink system. This enables satellites to talk to each other in orbit and thus eliminates the use of ground stations and also enhances the efficiency of routing.

This architecture makes less reliance on local infrastructure and enables connectivity in remote regions where the laying of fiber cables is not economically feasible - rural areas, deserts, oceans and war zones.

Fiber is not substituted with satellite internet. It adds to it a global, flexible access layer.

Low Earth Orbit vs Traditional Satellites

Previous systems of satellite internet used mostly used geostationary orbit (GEO) satellites. These satellites are at a distance of about 35,786 kilometres above the earth and they move at the same speed that the earth is rotating making them fixed to the sky.

GEO satellites have extensive coverage with only a few spacecrafts, but the distance is a major factor that causes a tremendous delay referred to as latency. To travel 500-600 milliseconds to serve as a latency, the signal needs to cover a distance of approximately 72,000 kilometres (up and down).

This is not too bad in simple web browsing. However, with real-time applications such as video conferencing, online gaming or stock trading these delays are apparent.

Systems like Starlink and OneWeb are modern with operation in the Low Earth Orbit (LEO), which is usually 500 to 1,200 kilometres above the earth.

The fact that the satellites are closer by far:

• The distance taken by the signal is much less.
• Under favourable circumstances, latency may decrease to 20-40 milliseconds.
• Real time applications are a lot more effective.

But a new challenge is made by lower orbit. LEO satellites travel at a high rate compared to a user. This implies that a single satellite is not able to cover a location continuously. In lieu of some massive satellites, corporations should install thousands of smaller satellites to establish a network of coverage that is continuously changing.

That is why Starlink has many thousand satellites and tries to make its constellation bigger.

The trade-off is clear:

GEO → Fewer satellites, higher latency LEO → Many satellites, lower latency

This transition to LEO constellations has altered the performance and competitiveness of satellite internet with terrestrial broadband fundamentally.

How Starlink Works

Starlink is a satellite internet constellation run by SpaceX, which is currently the biggest satellite internet constellation, having thousands of small satellites in Low Earth Orbit (LEO). Starlink is also a dynamic and moving network in contrast to the traditional satellite systems, which use a small number of large spacecrafts.

At the customer end, the customer mounts a small flat-panel antenna, commonly known as a dish, which in more recent models does not have any moving mechanical components. This terminal uses electronic methods of steering the beam to satellites flying over it. Due to the fact that LEO satellites move quickly throughout the sky the dish will always change connections between one satellite to the next, the user may often be unaware of this.

The satellite links with ground gateway stations which physically are linked to terrestrial fiber optics. When one user needs to access the data (as in opening a webpage), the signal would be sent through the dish to a satellite, and then to a ground station, the internet backbone, and then looped back.

Another technological breakthrough in more recent Starlink satellites is optical inter-satellite laser links. These lasers enable the satellites to transmit data directly to the other satellites in orbit. Data can pass through more than one satellite before reaching the earth rather than passing through a ground station where all the signals are sent. This eliminates the need to use dense ground infrastructure and is more efficient on oceans or remote areas. The outcome is a space-based mesh network, which is elastic, extensible as well as becoming less reliant on the heavyweight telecom infrastructure on the ground.

The Business Model

Satellite internet serves several markets:

• Rural households
• Maritime shipping
• Aviation connectivity
• Military and government communications
• Disaster recovery zones

Comparing Major Satellite Internet Players

The Role of Reusable Rockets

Satellite internet would not be economically viable without cheaper launches.

Reusable rockets, pioneered at scale by SpaceX, have reduced the cost of placing satellites into orbit. This allows companies to deploy thousands of satellites and replace them regularly.

The satellite internet boom is closely tied to launch economics.

Lower launch cost → More satellites → Better coverage → Lower latency.

What This Means for the Future

There are three ways satellite internet might transform global connectivity:

1. Closing the digital divide in the marginalized areas.
2. Giving backup support during natural disasters.
3. Enhancing the geopolitical dominance on the communications networks.

Governments are keeping an eye. Orbital communications infrastructure control could prove as valuable as fiber cables control under the sea.

With the increased size of constellations, space will cease to be a domain of exploration, instead becoming one of the primary strata of daily digital existence.