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Direct-to-smartphone satellite service: everything you need to know

In a historic first, Vodafone has made the first-ever video call over satellite from an area with no terrestrial mobile coverage. Here’s how it works and what it means for you.

Vodafone Group has just completed the historic first-ever space-based video call using 4G/5G smartphones, over a satellite built to offer a full mobile broadband experience, in a total not spot area.

Vodafone engineers had a video call with Margherita Della Valle, the CEO of Vodafone Group, while the engineers were in a part of rural Wales that’s a total not-spot, a place where there are no masts to provide mobile signal. Their Android smartphones were instead connected by satellite, a feat that has never been done before.

Astronaut Tim Peake and Margherita marked the milestone at Vodafone’s UK headquarters in Newbury, Berkshire. The headquarters is home to a ground-based relay station (more on this in a bit).

Although a test, its success potentially paves the way for the elimination of mobile coverage ‘not-spots’ in the future.

Haven’t satellite phones been around for a while?

Dedicated satellite phones can be large, chunky, heavy and expensive. As a result, they tend to be used only by people in specialist situations, such as long-distance sailors, alpine rescue teams and aid workers in disaster zones. The WhatsApp video call between Margherita and the engineers was done using standard off-the-shelf Android smartphones.

Aren’t all phone calls and internet traffic already carried by satellite?

No, that’s a commonly held misconception. The overwhelming majority of the world’s voice and internet traffic is actually carried by undersea cables.

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Does ‘direct-to-phone’ mean that satellite dishes aren’t required?

Yes, that’s the intention. In Vodafone’s test, the engineer’s smartphone was connected directly to a satellite. That satellite then transmitted data to and from a relay station on the ground. That relay station was connected to the rest of Vodafone’s network, including a standard mast, which is what Margherita’s smartphone was connected to.

Which satellite was used for the video call?

A Low Earth Orbit (LEO) Bluebird satellite operated by AST SpaceMobile, a Vodafone partner, was used for the video call.

Does direct-to-phone satellite service mean we don’t need network masts anymore?

Direct-to-phone satellite service can help provide signal to parts of the country and the world where it’s exceptionally difficult to build masts, such as especially remote rural areas – parts of the countryside where even initiatives like the SRN struggle to reach. Away from such areas, masts remain the most cost-effective way of providing the fastest and lowest latency mobile connections to as many people as possible, especially in built-up areas such as cities and towns.

When will direct-to-phone satellite service from Vodafone be available to the public?

It’s too soon to say, as Margherita’s video call was a test. But there should be more news in 2025 and 2026, once the company has completed further tests.

Can’t iPhones already communicate over satellite?

All iPhones released since the iPhone 14 in 2022 have a feature called Emergency SOS. This can send text messages to the emergency services over satellite. Only text messages can be sent and the experience is very different from standard texting. For example, you need an unobstructed line-of-sight of the sky and the horizon, with no trees or buildings in the way. If your view is obstructed, onscreen prompts will guide you to find a clearer part of the sky. Only text messages can be sent due to the limited amount of data that those satellites can carry.

As Margherita’s video call shows, the advantage of Vodafone working with AST SpaceMobile’s satellites is that more bandwidth is available so that other apps and services can be used. At the time of writing, other direct-to-phone satellite services only have enough bandwidth for voice calls and text messages.

Does Vodafone’s direct-to-phone satellite service also need unobstructed line-of-sight of the sky?

Direct-to-phone service doesn’t require an unobstructed line of sight to the satellite in order to make a good connection.

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Why can’t we use GPS satellites to connect our phones to the internet?

Putting aside the fact that GPS satellites don’t have the equipment needed to do this, the even-bigger issue is the height at which a satellite orbits the planet.

GPS satellites, which provide you with geographical location data in mapping apps and on satnav devices, are some of the highest satellites orbiting the Earth. At a height of 20,200 kilometres (12,550 miles) above the surface of the planet, they’re in a category known as Medium Earth Orbit [MEO] satellites. But this great height means satellites at such an orbit can typically only provide mobile data connections with slower speeds and much higher latency compared to LEO satellites.

There are many other considerations too. For example, MEO satellites need to be hardened to survive the radiation found at that height, something which isn’t an issue for LEO satellites.

So how high was orbit of the satellite that Vodafone used for Margherita’s video call?

The AST SpaceMobile satellite used by Vodafone for Margherita’s video call is a Low Earth Orbit (LEO) satellite. It sits at an approximate height of 500km (roughly 300mi) above the surface of the planet. This shorter distance makes it much more practical to provide mobile data connections with acceptable speeds.

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How fast is the mobile data connection over a direct-to-phone satellite service?

It’s too soon to say. Plus, the speeds achievable depend on environmental factors, such as having an unobstructed view of the sky.

The AST SpaceMobile satellite that Vodafone used can provide faster mobile data speeds than other LEO-using services as it uses a technique called beamforming. Already used in WiFi, as well as wholly terrestrial 4G and 5G networks, this technique precisely directs radio signals from satellites to their intended destination. This not only helps increase speed, but also minimises interference, increasing reliability.

40 years after making the UK’s first mobile call, we’re proud to continue our legacy as the Nation’s Network by bringing connectivity to all parts of the UK. The use of satellites in conjunction with our land-based network will ensure customers have the coverage they deserve. We’re excited to have successfully tested the technology and look forward to making it more widely available in the UK.

Max Taylor, Vodafone UK’s Chief Executive (and incoming CEO of the new combined Vodafone/Three business)

How many AST SpaceMobile satellites will be needed to provide a direct-to-phone satellite service to the public?

Like other comparable services, a constellation of multiple satellites will be needed to provide mobile signal. As the planet’s surface is curved, parts of it will inevitably be out of reach of the radio signals from any given satellite. That’s why multiple satellites are needed.

The expense of putting so many satellites into orbit, along with their limitations compared to ground masts, is why they’re a complement to ground masts rather than a replacement.

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