Not Dotnet: How Starlink works
Building your own satellite internet provider
Why Starlink?
It’s the year 2022, I live in Northern Indiana and I’m still waiting for fiber or cable internet to be accessible to my home. I live in the Fort Wayne metropolitan area (about 20 minutes away). I’ve been promised by Verizon that 5G will be a game changer and it’s coming “soon” (still waiting by the way).
By most accounts, I don’t really live rurally; my next door neighbor is in city limits. So why is it so hard to get reliable high-speed internet? It’s simple, it’s all about customer density.
If you look at the 5G rollouts, they are happening in the largest cities followed by highway coverage. Mediacom (regional cable provider) offered to run a coax line to my house for about $3000 + labor. There is fiber in my town but it’s on the opposite side of a railroad track which takes an act of congress to cross. Rural energy companies can’t afford to lay fiber (or coax) for a handful of customers as there would be no return on their investment.
So enter Starlink, a satellite internet provider where the customer density problem goes away because at the altitudes they operate — the ocean and polar regions are the only spots with not-a-lot of customers.
Satellite internet is slow right?
Getting your internet from the birds in the sky are not a new concept. If you’ve ever used some of the “legacy” satellite providers, you would be correct in saying they are slow, both in latency and bandwidth.
I was in the US Army for a bit as a communication satellite ground station operator/maintainer. The satellites we used (we called them birds) were geostationary (stayed over the same spot over the ground) and flew at an altitude of about 22,500 miles. When we made phone calls or bounced IP packets off the bird, the round trip was about 500ms. In some ways it makes the speed of light feel a little sluggish. Aside from the latency, there is limited bandwidth on stationary satellites. Any gamer out there knows that 500ms makes it impossible to play online multiplayer games.
What if we had more birds and they flew closer? Let’s look at what ingredients it takes to build a satellite provider.
It’s a bird, it’s a plane, no it’s a lot of satellites
When you are in a moving vehicle, sometimes your phone drops the call, but for the most part it doesn’t. This is because you are moving in relation to fixed stationary cell towers. As you move the communication gets “handed off” from one tower to another. Your cellphone is a tiny little radio with a modem in it that broadcasts and receives analog radio waves encoded with digital information.
Starlink is sort of the inverse of the cellphone model. Instead of the cellphone operator moving, the “cell towers” move instead. Of course in a satellite provider world, the cell towers are satellites which is the first ingredient of making your own satellite provider.
3, 2, 1… Go fast
There’s a few sticking points with satellites though, they have to fly around 17k MPH so they don’t fall back to Earth. They also have to get to an altitude of about 210-800 miles (depending on generation of satellites). Therefore to get our birds into position, we’re gonna need some rockets — our second ingredient to building your own satellite provider. Fortunately Starlink is something SpaceX operates and they have a lot of rockets.
No really, it takes a lot of satellites to make this work
It takes three satellites to cover most of the population of Earth from the traditional altitude of 22,500 miles. The Starlink birds are much closer to Earth which reduce latency to under 10ms. The improvement in latency means that instead of three birds to cover most of Earth, you’ll need thousands. Starlink has placed over 3000 birds in the sky, some of which have already been retired. Each bird makes one complete revolution around the Earth in about 90 mins (like the International Space Station does).
Mission Control to Major Tom
Having thousands of satellites in the sky is essential to provide low-latency internet. However if they don’t communicate with your house/home/RV, what good is it? Therefore if you want Starlink to bring you the latest Netflix/HBO streaming series, you’ll need a satellite dish to communicate with the birds — our third ingredient. Since those birds are moving around very fast and at very low altitudes, you’ll have to always have one in the sky visible to your dish; otherwise there will be a lot of buffering in your life. So how many satellites are buzzing overhead your house at any given time? It depends of course, but you’ll wanna check out this tool which is not affiliated with Startlink/SpaceX. According to it, you should ideally see anywhere from 8-10 satellites within line-of-sight of your dish
Staying Grounded
Let’s recap our ingredients of Starlink so far, we have satellites, we have rockets, and we have satellite dishes; what else do we need to complete our satellite provider?
We need ground stations — the final ingredient. A ground station connects to the backbone of the internet just like if fiber ran to your house, the other end will end up a the internet service provider which connects to the internet backbone. If we were to trace out the path of internet packets from your Roku (connected with Starlink), it would look like the following:
Request leaves your Roku
Goes through you local network (router/switches)
Goes out your dish
Makes it to an overhead satellite
Beams back down to a ground station
Continues to Netflix/HBO through the internet backbone
Then the streaming movie comes back in reverse
The tricky part is the hand-off dance as satellites zip by overhead. The satellites themselves have to see both you and your house (presently) in order to connect the pipeline of packets. There are a limited number of both satellites and ground stations which create bottlenecks for Starlink.
The next generation of Starlink satellites will add the ability for the birds to talk to each other in orbit in order to overcome situations where a ground station is not in view. For instance, if you’re in the middle of the Pacific Ocean, the chances of the birds seeing a ground station is almost zero.
What could go wrong?
Starlink is a pretty amazing and ambitious idea. There is presently a very large and lengthy waitlist. I’ve been on the waitlist for over a year. The amount of customers in an area is influenced by both the number of satellites and the number of ground stations in an area. Too many customers in one area, will overload both satellites and ground stations.
The United States regulates (via the FCC) the number of satellites that a US provider can use, the orbit and the radio frequencies involved. However the FCC’s jurisdiction stops at the borders of the US. This means there are other countries looking to build similar constellations of satellites. This proliferation of satellites creates a lot of potential future space junk and the potential for a Kessler syndrome event to occur. It also creates a virtual “orbit grab” where the first to get there wins.
Additionally astronomers have had a rough time with getting clear pictures due to the sheer amount of satellites crossing overhead during long-exposure photography.
To infinity and beyond
Starlink solves the customer density problem to make rural internet economical. It obviously comes with a lot of baggage (potential for Kessler syndrome/astrophotography). I am looking forward to what Starlink will be able to provide humanity over the next decade. If you’re wondering what I’m using while I wait, I’m on a line-of-sight system that bounces off a few buildings before terminating at a cell tower. Not ideal, not the worst; but leaves a lot to be desired. America has long way to go to bring high-speed internet to the masses.
One thing I like to point out about internet speeds is the difference between latency and bandwidth. Gamers prefer low-latency which is often not advertised by ISP’s. Rather, you’ll purchase plans typically by bandwidth. This means that you might actually enjoy a 20MB/20ms connection much more than a 100MB/100ms connection. Keep that in mind when trying to compare ISP’s.
If you’re waiting for Starlink in your area, you need three things to happen:
Ground stations close by (remember the satellite has to see both the ground station and your dish).
Satellites passing overhead with bandwidth available.
Satellite dish production issues (e.g. chip shortage) to be resolved.
This post is not sponsored by Starlink/SpaceX, I just wanted to share some of the things I’ve learned over the last couple of years while I wait for this to become reality.
Another great article. Very enjoyable read. You may or may not want to Google ‘why is 5G bad for airplanes’