[Starlink 1] Things you were too afraid to ask: What exactly is so amazing about SpaceX's "Starlink"? | Latest technology in 5 minutes

This series focuses on the latest technology.
From space development, AI, and quantum technology to general scientific topics, I explain them from an engineer's perspective.
Whether you're someone who isn't good with complicated things, or someone who is interested but doesn't really understand it, this is delivered with the concept of "being able to understand it quickly in 5 minutes."

Now, the theme for this time is the long-awaited "Starlink."
Speaking of Starlink, a service called "au Starlink Direct" was recently launched. With TV commercials and advertisements running everywhere, even if you don't know much about it, you've probably at least heard the name, right?

The much-talked-about "Starlink" seems new and amazing.
But do you know what exactly is so amazing about it?

🛰️ What exactly is Starlink?

If you look up "Starlink" on Wikipedia, it says, "A satellite internet access service operated by SpaceX, as well as the satellite constellation that realizes it."

A satellite constellation is a system where many satellites work together and are operated as one unit.
In other words, "Starlink" refers to thesystem that links many satellites operated by SpaceX, and theservice that connects to the internet using that system.

As I wrote at the beginning, I think most people know about it from au's commercials and ads, so you might think, "It's a service where you can use your smartphone with radio waves from artificial satellites, right?"
You might think that.
However, the main service of Starlink currently is one where you can connect to the internet if you install a dedicated antenna.

Above is the dedicated Starlink antenna.
This is something that is fixed at home, but there are also types that you can carry around and use anywhere.
The service that connects to smartphones started this year (2025), but services for these dedicated antennas started in the US in 2020 and in Japan in 2022.

And,the biggest advantage of Starlink is that you can connect to the internet anywhere in the world, at any time, as long as you have power.

Usually, to connect to the internet, you either have to bring a cable like a fiber-optic line to your home, or connect wirelessly to a base station with your mobile phone, right?

However, there are still many places where you cannot connect to the internet, not only on the ocean or in the sky, but also on land, and in the event of a disaster, it is common for mobile phones to be unusable even in environments where they are usually connected.
Starlink is about filling those "network blank spots" from space.

🤔 So what exactly is so amazing about it?

You might think that this alone is amazing enough!
But actually, Starlink is not the first service that allows you to connect to a network via communication satellites.

In fact, satellite phone services have existed since the 1990s, when regular mobile phones were finally starting to become popular, so they have a history of about 30 years.

Then, what exactly is so amazing about Starlink?

📡 Until now, geostationary satellites were used

Before Starlink appeared, internet services using communication satellites mainly used geostationary satellites (GEO).

The reason for using geostationary satellites is that the biggest reason is that one unit can cover a wide area. If the coverage area is wide, the number of satellites needed is small.

Also, with geostationary satellites, the satellite's position as seen from the ground is always the same. Since the antenna direction can also be fixed, you can use relatively inexpensive antennas. That part is the same as a BS broadcast antenna.

🚅 Overwhelmingly low communication latency

However, geostationary satellites have a major weakness.
As I explained in a previous article, the satellites are too far away, resulting in high latency. In other words, it takes time for signals to arrive.

The altitude of a geostationary satellite is about 36,000 km.
Communication via satellite results in a response delay of about 0.6 seconds.
0.6 seconds might not seem like much, but when you actually use the internet, you might find it a bit frustrating because the response is one beat behind.
This is quite awkward for real-time calls or web conferencing, and it's basically impossible for competitive online games.

In contrast, Starlink uses low Earth orbit (LEO) satellites at an altitude of about 500 km.
The latency is only about 0.05 seconds, so it is at a level where it can be used without stress for most purposes.

😄 Peace of mind even when congested due to the overwhelming number of satellites

The advantage of geostationary satellites is their wide coverage area, but conversely, it means one satellite has to cover a vast area.

Internet communication via geostationary satellites includes services like Viasat and HughesNet in the US, but all of them use only a few geostationary satellites.

Because of this, while high-capacity communication is possible, the area covered is still too large for the number of satellites...
During busy times, it can be difficult to watch videos and the like.

On the other hand, the number of active Starlink satellites as of October 2025 is a staggering 8,600 or so!!
Of course, since the area one satellite can cover is small, many satellites are required.
However, with such a difference in numbers, the difference in communication capacity is overwhelming and incomparable.

🌠 Actually, there's more to it than this. What is the true greatness of Starlink?

So, to sum up the greatness of Starlink in one word, it is because it can
"provide a comfortable internet environment with low latency, anytime, anywhere in the world"
.

How about that?
Now that you understand this much, have you been able to grasp why Starlink is so amazing?

But...

Actually, the greatness of Starlink doesn't stop there.
How was Elon Musk, who leads SpaceX, able to realize Starlink when other companies couldn't until now?
That is where the true greatness of Starlink lies.

And Starlink is still evolving.
To be honest, we are still in the early stages of the plan. How will it continue to evolve and become even more amazing from here on?

I would like to continue, but it has become long, so I will end here for now and continue next time.

📝 Summary

So, starting this time, I will be explaining Starlink, which everyone has heard of.

I was thinking that it would be difficult to finish in one go, so I might split it into about two parts, but when I actually started writing, I only got about halfway through what I had planned for the first part.

Since we have barely touched upon the smartphone service mentioned at the beginning, I have a feeling this is going to be a rather long series...
I hope you will stick with me without getting bored.

With that said, look forward to the second part of the Starlink explanation!!