How does Starlink Deliver Broadband from Space?

It has been all the talk in satcom for the past few years, and rightly so. Starlink is looking likely to reshape what it means to be operating a telecommunications network. With its vast constellation of satellites in orbit and the target to connect rural and urban populations alike, soon, there will come a time when there will be no need to huge towers that take up too much space and cables, wires, fiber that crisscross the globe. But how will Starlink manage to achieve that?

Starlink - A Truly Grand Constellation

Right now, the Elon Musk-led companies are hard at work completing the Phase 1 of 2 of deployment. Phase 1 will go on till March 2027, with its halfway point coming in March 2024. In the first phase, SpaceX is looking to deploy 4,396 satellites in 4 different orbital shells around Earth. As of now, work on the first shell is more than done, with 1,625 satellites in place out of an original 1,584. Apart from that, Starlink also has 10 satellites in the 560 km shell as well, taking its tally to 1,635 satellites.

SpaceX has had 12 Starlink launch missions in 2021, launching 712 satellites in orbit. SpaceX has already planned Starlink mission in July, August and September. This means that barring June, there has been no month without a Starlink mission.

SpaceX said last year that it is manufacturing around 6 satellites a day. Usually, the company starts scheduling the launch once a batch of 60 is ready. SpaceX uses its Falcon 9 rocket as the delivery vehicle for the satellites. Called the workhorse of SpaceX, Falcon 9 is a 225-foot, reliable piece of hardware that has high reusability. Last month, a Falcon 9 rocket took 60 satellites to orbit in its 10th launch, a new record.

Given its already huge constellation, Starlink is already out with beta-level services in many parts of Europe and North America, with a commercial launch planned in June 2022 in India as well. However, as the demand rises, SpaceX plans to use its largest rocket ever, the Starship, for launches. Capable of carrying more than 100 Tons of payload, it can potentially launch 200 satellites in one go, which will speed up deployment by a lot. At completion, Starlink will have a constellation of 11,914 satellites around Earth.

That means, by the time 2028 rolls over, there will be more Starlink satellites in orbit than there are stars visible in the night sky - a truly remarkable feat.

This is how the Phase 1 of Starlink Satellites looks like. Image is not to scale.

A Choir in Space

As we have established already, there are quite a few satellites that are going to be orbiting once all the deployment finishes. As such, to maintain a network, all the elements should be able to connect with one another. Since we can't put wires on the satellites like some sort of garlands slowly drifting around the planet, the satellites communicate via lasers.

Yes, lasers. More specifically, in each of them, there is a element fitted called Laser Inter-Satellite Links. Basically, these are optical elements that allow satellites on the same orbital plane to communicate with one another. In each of the Starlink satellites, a 1.50-kilo silicon carbide LISL element comes fitted.

This allows satellites as far as 5,000 kilometers to communicate at a link data rate of 2.5 Gbps. The LISL element allows for 4 connections at a time. This allows a satellite to connect with three satellites in its own plane, and one in the adjacent planes. Newer satellites have 5 LISL capabilities, which will improve interconnectivity once more satellites reach the orbit.

There are many types of connections these satellites can form while in space. In short, owing to their orbital inclination and heights, these smallsats are able to connect with satellites via either permanent or temporary LISLs.

Essentially, to maintain a constellations, each satellite needs to be connected in the system. An intricate system of optics, lasers and positioning, Starlink manages to bring together each singing satellite and makes them into a choir.

From the Constellation to the Dish

For starters, it won't connect directly to your phone. Instead, Starlink uses a flat user terminal. The user terminal will have a phased antenna, that will track the satellites via motors. So, as long as the dish is looking at the sky, it can receive signals.

This is what a Starlink User Terminal and its Antenna looks like.

The fact that the terminals are so portable, they can be mounted anywhere, even on moving objects like trains or ships. Elon Musk had earlier said that the terminals would look like a "UFO on a stick". Funnily enough, the antenna is called "Dishy McFlatface" by the staff.

The basic process is similar to how a DTH service operates. The satellite emits signals and the dish catches them. However, these satellites are much closer to Earth than a normal TV satellite. A DTH satellite is a geostationary satellite and is huge.

For example, Tata Sky, a DTH service, uses GSAT-10. This satellite is a 3.5 tonne ISRO-made behemoth, orbiting the planet from almost 36,000 kilometers away.

In comparison, a Starlink satellite orbits about 80-100 times closer and is about 80-100 times lighter.

Here's the catch - broadband is mission-critical, DTH is not. That's why, Starlink satellites need to be closer to Earth. Even though light is fast, signals still takes time to travel to Earth. In DTH signals, typical latencies range from 2-10 seconds. For satcom, this delay will just make it unusable. However, being 100 times close to Earth reduces the latency by a factor of 100 as well - to 20-100 ms. This latency is around the same as optical fiber, making Starlink very usable.

Broadband to Home, in Cities

For the time being, Starlink is looking set to expand their network to remote areas, where telecom connectivity is either low or absent. However, Elon has said that they are actually targeting urban areas, with high user density.

A Starlink satellite sends internet down to all users within a designated area on the ground, called a cell. However, you can only use the internet within the cell your connection is associated with. That means, if you move your Starlink outside of its assigned cell, you won't receive internet. A cell looks like this:

A Starlink Cell over Minnesota, US.

The fact that you can only receive internet while being inside a designated cell limits its moving applications quite a lot.

However, to counter this issue, Starlink has been hard at work to utilize its network in the cloud internet space. On 13th May, SpaceX announced its partnership with Google for on-ground equipment. Basically, that means that Google will allow its users access to Google Cloud without the need of a cellular connection. Starlink will run applications within Google data centers to increase performance. SpaceX President and COO Gwynne Shotwell said that, in return, Starlink customers will leverage Google’s infrastructure and capabilities for secure connections.

Also, Starlink announced a similar alliance with Microsoft in October last year. Microsoft said Starlink will support its new space-focused, modular cloud business called Azure Space, which will offer mobile cloud computing data centers that it can deploy anywhere in the world.

The Novel Features of Dishy McFlatface

Finally, we discuss one of the integral elements of the system, Mr. Dishy McFlatface. The cute little antenna dish which comes bundled in as a part of the user terminal has a couple of novel tricks up its sleeve.

1. It is capable of auto-configuring. That means, once installed, it will automatically face towards the region of sky where it will receive internet from. It can do this with the help of the motors that come fitted in the dish.
2. Dishy can melt all the hail and snow that gathers on it, keeping itself clean.
3. Dishy also meets US NEC grounding requirements.

However, it needs clear, unobstructed view of the sky. Starlink's website makes this clear; even a brief interruption can plummet your internet speeds. To counter this, SpaceX plans to put up more satellites. That may or may not be a good idea.

(This was a rather unnecessary section, but oh well.)

To the Stars, or Maybe Not

If you have the time to dig around in Starlink's Terms of Service, you will find point 10, called Governing Laws. At one point, it reads,

For Services provided on Mars, or in transit to Mars via Starship or other spacecraft, the parties recognize Mars as a free planet and that no Earth-based government has authority or sovereignty over Martian activities. Accordingly, Disputes will be settled through self-governing principles, established in good faith, at the time of Martian settlement.

It is a major spoiler for the things to come. Elon has never made secret of his desire to settle people on Mars. To that extent, he is looking a Starlink as a plan grander than anything else like it.

SpaceX will deploy satellites around Moon, and Mars as well. That means, the total Starlink megaconstellation will have around 42,000 satellites. Even now, planning to put up 11,914 satellites in orbit is ridiculous.

To put that number in perspective, in all of history, only 11,670 satellites have ever been launched, per European Space Agency. Out of those, only 4,300 currently orbit the planet. These many satellites, in Musk's words at a Seattle speech in 2018, "will be like rebuilding internet in space".

However, the sheer number of satellites pose a serious threat to any and all astronomical observations on the planet.

Signal pollution in a 333-second exposure image taken from the Blanco four-meter telescope at the Cerro Tololo Inter-American Observatory.

The white lines in this image are the company's satellites. SpaceX has started to put on a non-reflective coating but painting the satellites black won't do. People need to look at space, not at little black spots zooming around. The International Astronomical Union expressed concerns in a statement released in June 2019. It read, "satellite constellations can pose a significant or debilitating threat to important existing and future astronomical infrastructures, and we urge their designers and deployers as well as policy-makers to work with the astronomical community in a concerted effort to analyze and understand the impact of satellite constellations".

Will Starlink be the Future of Internet?

The broadband market is worth $1 Trillion at the moment. Starlink forms a part of Elon Musk's grand Mars colonization project, and capturing that market is one of the top agendas of the company. Their prospects looks fine, the company has quite the technological head-start over competition, yet, there is a lot missing, a lot to be desired.

First, the geographical limit severely hampers any mobile usability. Starlink needs to fix that. It can achieve that, obviously, by putting up more satellites, or by setting up ground receivers and distributing the internet by fiber. Sure, that sort of defeats the purpose of Broadband to Home, but that bit can help them capture a larger market share and drive down costs for the customers as well. Right now, the dish costs $499 and the service costs $99/months. So: not affordable.

Second, it needs to work on the efficiency of its receiver dishes if on-ground distribution doesn't work. Right now, it is sensitive and the connection is fragile. Simply putting up more satellites is an option, again, but still.

For a beta product, Starlink is managing to pull its weight. However, it needs to do more to become a major threat to on-ground broadband players.