LEO Constellations: A Turn-Key Solution for Datacenter Connectivity Redundancy

Louise Matias IV Velayo

June 4, 2022
TABLE OF CONTENTS

Receiving internet connectivity from space has been around for some time and is for many rural areas their only option to “connect”. Today, some companies are aiming to make satellite internet more abundant, by selling it cheaper and providing higher speeds. This is not done by magic, the secret is: LEO constellations. Now, what are those? And does satellite internet actually serve value? 

Leo Constellations - At the Forefront of Cutting Edge Space Tech

Low Earth Orbit (LEO) describes an orbit that is close to the Earth’s surface. According to the European Space Agency, this is typically less than 1000 km and could be as low as 160 km. Don’t worry, commercial airplanes do not fly at altitudes much higher than 14 km which is ten times lower than the lowest LEO.

Today, there’s a lot happening in  LEO and it’s getting crowded. One of the largest applications for LEO satellites is providing satellite-based internet through large constellations. These constellations act as a revolving mesh network around the world which, depending on the networks’ size, could potentially provide connectivity anywhere on Earth. This can be done without the need to install expensive ground infrastructure and run cable or fiber lines to everyone’s home. Such methods fail to provide universal connectivity.

Did you know that nearly 40% of the world’s population has never used the internet? And this is despite the connectivity boost that was observed during the pandemic. LEO satellite internet has the potential to reduce this digital divide.
Starlink user terminal | Image by John Kim via cnet.com

To explain the general working principle, Let’s take a closer look at Starlink, a SpaceX company providing LEO satellite internet. Users of the service require a user terminal, which is essentially a satellite dish the size of a bicycle wheel, and in the case of their business terminal, it is comparable to the size of a 24’’ monitor. Thanks to the user terminal, users can communicate with one of the LEO satellites that are in proximity. This is half of the story. The LEO satellites need to connect with a ground station which is on Earth. Similar to the user terminal, this only occurs when the LEO satellite is in the visibility region of the ground station. The ground station connects to the internet backbone, a network of fiber optic cables that run between datacenters, giving the LEO satellite and end-user access to the worldwide web. 

Starlink Business terminal | Image by theverge.com

Ground Stations: The Space-Internet Bridge

Ground stations can communicate with LEO satellites only when the satellite is in its visibility region. The duration of the visibility and the communication vary for each LEO satellite that passes over the ground station since LEO satellites move too fast over the Earth. The satellite coverage area is defined as a region of the Earth where the satellite is seen at a minimum predefined elevation angle. The elevation angle is the angle between a satellite and the observer’s horizon plane. In this case, the observer would be Starlink’s ground station.

Diagram of elevation angel | Image by tutorialspoint.com

Ground stations house tracking and telemetry hardware, power connections and redundancy options. But, the bridge to space is made through the satellite dishes located at these sites. The type of satellite dishes at a ground station varies per site. In the case of Starlink, their satellite dishes are housed in a white dome structure called a Radome, which is a weatherproof enclosure that minimally attenuates signals. This is used to protect the antenna as well as conceal the technology being used. 

A representative example of a Starlink ground station | Image by Steve Baker via quora.com

The main function of these dishes is to convert the radio frequency signal coming from the LEO satellite into a signal that can be transmitted by terrestrial networks. For Starlink, these would be signals that are transmitted via fiber optics that connect to datacenters. Based on their functionality, there’s reason to believe that the dishes used at Starlink ground station are different from their user terminals.

It becomes clear that ground stations play a pivotal role in the working of Starlinks satellite internet service. Without ground stations, LEO satellites and user terminals would not be able to access the internet. Naturally, the number of ground stations should expand as the LEO constellation expands. For Starlink, this will certainly be the case as according to the paperwork SpaceX has filed, the LEO constellation plans to increase from 2,500 satellites to 30,000.

Datacenter Ground Stations

According to ookla.com, Starlinks services around the globe have been matching and even outperforming local fixed broadband providers , and this is only with 8% of their planned satellites up in space. Seeing the potential of this technology, hyperscalers are developing their own satellite internet services and having their ground stations in close proximity to their datacenters.

Last year, SpaceX announced that they would partner with Google and house their ground stations within Google datacenter properties. The main motivation behind placing these ground stations closer to datacenters is to provide single-hop access. Due to the nature of satellite internet, latency is a metric where fixed broadband continues to outperform it. However, by establishing these direct connections, latency can be reduced which can improve overall performance.

Before, these ground stations were siloed and normally placed in rural/remote areas, but as the performance of these LEO satellite internet services continues to improve, we could see a growing number of combined datacenter ground stations.

But why stop there? Could there be other components of LEO satellite internet that could be brought closer to datacenters?

Satellite Internet as a Connectivity Redundancy Option for Datacenters

It was mentioned in previous paragraphs that most (Starlink) user terminals are placed at the homes of customers. What if these terminals were used at datacenters to provide redundant datacenter internet connectivity. 

According to Uptime Institute, between 2016 and 2018, 27% of datacenter outages were due to network problems, making it one of the leading causes of data center outages.

Networking issues are increasingly becoming the cause of service degradation while power outages are becoming less of an issue. This could be attributed to the rise in the interconnectedness of things. The statistics presented identify a need for increased redundancy in datacenter internet connectivity, which could be provided through LEO satellite internet. Assuming such an integration is possible, datacenters with such a redundancy option would be more robust to outages caused by network issues.

Unfortunately, the latency for LEO satellite internet still lags behind fiber-optic broadband networks. So, it may be a while until we see user terminals being placed at datacenters. However, if more datacenters build ground stations on-site and if further innovations are made to reduce the latency gap, LEO satellite internet is positioned to provide internet connectivity redundancy to datacenters. 

At aviate labs, we are exploring this route with our datacenter partners and node clients.