Starlink and new satellite services could beat Internet cable breaks – MyBroadband

The ability of SpaceX’s Starlink Internet service to transmit data packets between its fleet of satellites makes it capable of circumventing undersea cable breaks.

This feature could soon also be supported on other satellite services, lessening the impact of cable breaks on global Internet connectivity.

Many users of Starlink’s roaming service in South Africa recently reported their connections were not impacted by the four undersea cable breaks along Africa’s West Coast.

The incident, believed to have been caused by a submarine landslide, disrupted Internet connectivity and caused intermittent issues on many online services in South Africa and other African countries in mid-March 2024.

On Vodacom, it led to a prolonged shutdown of mobile data services.

While many providers have rerouted traffic to alternative routes, this has increased latency and full capacity is not expected to be available until the cable breaks are fixed.

Starlink roaming unimpacted in South Africa

Those who were using Starlink in South Africa reported no such problems.

This is because their data traffic was not routed through these cables but relayed between satellites to ground stations on the other side of the breaks.

The SpaceX team have dubbed the technology that facilitates this “space lasers”, but they are officially known as Optical Inter-Satellite Links in the satellite industry.

While Starlink did not invent inter-satellite communication, its fleet has the highest number of laser links and biggest bandwidth of any operator.

These links transmit data using “lightwaves”, the part of the electromagnetic spectrum spanning infrared, visible, and ultraviolet light.

The tech has proven so successful that SpaceX president and chief operating officer Gwynne Shotwell recently said the company would start selling it to other satellite broadband providers.

“We are going to roll out a capability, we call it ‘plug-and-plasers’,” Shotwell said at an industry conference.

In January 2024, PCMag reported SpaceX engineer Travis Brashears said that the system was transmitting around 42 million gigabytes of data daily and had a peak throughput of 5.6 terabits-per-second (Tbps).

To put this into perspective, South Africa’s biggest Internet exchange point — NAPAfrica — recorded a peak throughput of nearly 4Tbps in late March 2024.

Each laser link can sustain a 100Gbps connection, so they can transmit 12.5GB of data every second. At peak throughput, this can increase to 200Gbps or 25GB/s per link.

The links consistently communicate, with around 266,141 “laser acquisitions” per day.

To date, the longest recorded connection between two Starlink satellites was 5,400km.

Brashears said Starlink could dynamically change the routes its satellites’ laser links follow within milliseconds.

To illustrate this, he presented a slide which showed how the laser links could transmit data to a Starlink dish in Antarctica using about seven different paths.

“As long as we have some path to the ground, you’re going to have 99.99% uptime. That’s why it’s important to get as many nodes [satellites with laser links] up there as possible.”

Ground infrastructure remains necessary

It is important to emphasise that Starlink and other satellite broadband services could never operate independently from ground infrastructure.

This would require the data centres holding the Internet’s content to be moved onto satellites in Earth’s orbit.

Starlink’s fleet needs to link up with its ground stations at some point in the connection process.

In many countries where Starlink has officially launched its services, these ground stations are already in operation and provide Starlink users with latencies below 50ms.

The Starlink satellite-to-satellite links ensure that those users who are connecting to satellites far away from ground stations can also use the Internet, albeit with additional latency.

This is the same for Starlink roaming users in South Africa, where SpaceX has not officially launched.

Although a ground station being constructed in Mozambique could significantly reduce latency, Starlink users in South Africa currently experience latencies of over 100ms to a ground station in Nigeria.

While Starlink’s constellation consists of over 5,500 satellites, those with space lasers were only introduced in September 2021.

That means their concentration is not high enough to compete with fibre’s latency in countries where ground stations are not available.

Better latency than fibre in the future

However, calculations by a computer science professor have shown that Starlink could eventually also beat undersea cables in latency once it has more space laser-equipped satellites in orbit.

Professor of Networked Systems in the Department of Computer Science of University College London Mark Handley illustrated that the round-trip latency between Johannesburg and London could be cut to 100ms using the laser links in Starlink’s constellation.

As it stands, the round-trip latency between these two locations is around 160ms when using the fibre submarine cables running along Africa’s West coast.

The image below shows one of the possible routes on which a data transfer could travel using only satellite-to-satellite links between Johannesburg and London.

In another simulation, Handley placed hypothetical ground stations in towns with at least one mosque on a pathway between Johannesburg and London.

He found that latency of 77ms–82ms could be achieved by bouncing data from the user to satellite to ground station, then again to satellite and to ground station.

With a combination of the laser links and ground stations, Handley calculated stable latency could drop to as low as 75ms.

Starlink’s satellite-to-satellite and general performance is expected to improve drastically in the coming years.

As it stands, there are roughly 9,000 laser links across the current constellation.

The company has approval from the Federal Communications Commission to launch 12,000 of its satellites into orbit, nearly double the size of its current fleet.

It aims to launch another 30,000 satellites to take its final tally to 42,000.