[Technology Essay] The Ukrainian-Russian War and the Starlink Project

Ukrainian-Russian War

Since the outbreak of the Ukrainian-Russian war at the end of February, the world has been experiencing many major events. Many people have said that Bitcoin is a theory of digital gold, a safe-haven asset, etc. I think it has also undergone a round of verification this time. The current cryptocurrency market situation, let alone a hedging tool, the market even regards it as a risky asset. When the situation is unclear, investors should withdraw funds and flee, and the leeks have all cut their meat and ran away. . I wrote an article explaining the principles and risks behind dual-currency investment. If you want to buy the dip for the recent market conditions, you may consider using the “dual-currency investment” strategy to go long.

Returning to the topic, due to the outbreak of the Ukrainian-Russian war, the backbone of the local fixed network in Ukraine was bombed by Russia, causing serious problems in the network communication of many cities in Ukraine. The picture shows the network of Karkov, the second largest city in Ukraine, before and after the outbreak of the war. road connection status.

Worried that Ukraine will be cut off from the Internet, Ukraine’s Deputy Prime Minister and Minister of Digital Transformation, Mykhailo Fedorov, asked SpaceX founder Elon Musk on Twitter to enable Starlink services and equipment supply in Ukraine .

The follow-up also received a positive response from Elon Musk, announcing that Starlink has opened services in Ukraine and is shipping more receiver equipment to Ukraine.

I don't know what courier service SpaceX uses, but the equipment was received in Ukraine on 3/1 every two days...

Just like the last time the network communication of Tonga Kingdom was destroyed due to the eruption of the submarine volcano, SpaceX also set up Starlink infrastructure there to help restore local network services. After these devices were set up and connected to satellites, they quickly assisted The restoration of Internet communication in parts of Ukraine makes me curious, what is the operating principle behind the so-called satellite communication Internet access, and what is the ultimate goal of the Starlink project that SpaceX is implementing, such technology may be useful for human civilization and life. What kind of breakthrough?

Starlink Plan

Starlink is a plan released by CEO Elon Musk in 2015 by the space exploration technology company SpaceX. Its goal is probably to develop a "global satellite Internet system", by launching a bunch of low-orbit satellites, so that the world can be covered Within the range that satellites can receive, the advantage of this is that it can provide a global network that is not limited by ground infrastructure, so those areas where the infrastructure is still underdeveloped, or the network is interrupted for some reasons, can be Satellites communicate normally, so everyone in the world can connect to the Internet from anywhere.

The Starlink project seems to be quite far away from our lives. This plan also sounds like the future technology will not be realized so quickly, but in fact, it has officially started to provide services in the United States since the end of 2020, and will continue to provide services. The service has been extended to the whole world, and at the time of writing, it has been used in 29 countries, including the Pacific island country Tonga, which is affected by submarine volcanic eruptions, and Ukraine, which has been invaded by Russia. Their goal is to complete about 12,000 satellites by the end of 2027. Satellite deployment, 1,791 satellites have now been launched.

These 12,000 satellites will be sent in different orbits, of which about 7,500 are in the orbit of 340 kilometers, about 1,500 are in the orbit of 550 kilometers, and about 2,800 are in the orbit of 1,150 kilometers, although they are all low-orbit satellites (low orbits). The definition of satellite is about 2,000 kilometers below the ground), but satellites at different altitudes are responsible for different matters due to the different coverage and the design of the satellite itself. Usually, the higher-altitude satellites emit higher frequency bands. After the completion of this stage, the next stage is expected to have 30,000 satellites, and finally use these 42,000 satellites to form a star chain, covering the entire earth.

I think for Musk, this goal may be just a small step for him. After all, for him who said he is going to colonize Mars, if this system can be used in space environments such as Mars, then in the Mars network Road communication, communication between Mars and Earth, and even communication within the entire solar system may be a major advance.

Here is a pretty cool website that can track the real-time location of all Starlink satellites and the current service range around the world. URL link: https://satellitemap.space/

communication satellite

If you want to understand very simply what a communication satellite is, you can imagine that a communication satellite is to change the base station originally placed on the roof of your building into a similar thing in space, and the distance from the earth can be used to divide the satellite into Three categories:

1. Geostationary Earth Orbit (GEO), refers to a satellite 35,786 kilometers above the Earth's equatorial plane. A satellite in this orbit orbits the Earth for the same time as the Earth's rotation period, that is, above your head. The satellites will always be above your head. Since the distance covering the larger transmission on the ground is relatively long, as long as three satellites are enough to cover the entire earth, there will be a communication delay of about 250 milliseconds in communication.

2. Medium Earth Orbit (MEO), refers to satellites between 2,000 and 35,786 kilometers above the Earth's equatorial plane. Satellites operating in this orbit orbit the earth for less than 24 hours, and the shortest period ( For circular orbits with the lowest MEO altitude), it can be up to 2 hours, which are usually navigation satellites, such as the Global Positioning System (GPS) we use every day, and the communication delay time is about 100 milliseconds.

3. Low Earth Orbit (LEO), refers to satellites below 2,000 kilometers above the Earth's equatorial plane, and the satellite orbits the Earth within 128 minutes. Communication satellites, the International Space Station where astronauts go out to space are also in this range, so it is only in early December 2021 that China protested that their space station was almost hit by an American satellite twice. The chain plans to send tens of thousands of satellites. If it is not well managed, we may have the opportunity to see satellites collide. As the distance of the satellites in this orbit increases, the communication delay will probably not exceed 20 milliseconds at most.

The advantage of the communication satellite is that the coverage area becomes very large, and it can no longer be limited to the surrounding of the house. It is more remote and sparsely populated or on the mountain. The cost of pulling a fiber will be very high and the efficiency will be low. It can be changed to A ground receiver is placed in the backbone network and the place to be connected, and then the communication satellite is used to connect the two places, so that the cost will be very low.

Because the distance increases, satellites in higher orbits will have a slight delay in information transmission, which is not technically faster than optical fiber networks in a short period of time, and because the base station is difficult to maintain in space, it usually costs a lot of money but The lifespan is relatively short. In addition, the base station needs to transmit a higher frequency to communicate with the communication satellite. The penetration power of high-frequency things is very low. I have seen some examples of actual erection abroad. Some people say that even branches can interfere with the signal, so generally The use of communication satellites in crowded cities is not very beneficial, but Europe and the United States may be a very good market with sparsely populated areas.

How Starlink Works

So much has been said before, so how does Starlink work?

The Starlink project has designed two "links". The services currently provided are in the first stage. The connection method is to connect two ground receivers in series through a communication satellite, one of which is the user and the other is the network service provider. As shown below:

In the first stage, the request sent by the user will be forwarded to the ground receiving station closest to the user via a communication satellite, and then the receiving station will connect to the network service provider, and after getting the response from the server, the user will follow the original route. When collecting data, you can see at a glance that this method cannot be faster than direct access to the optical fiber. Because there will be delays when the ground and satellite transmit information again, so there will be at least 4 additional communication delays in the communication. .

The "link" of the second phase of the Starlink project, in addition to the method of the first phase, can also be transmitted between satellites, so that the signal can reach farther, and will not be limited to a small area. , the schematic diagram is as follows:

This second-stage plan seems to be the same as the first stage, except for the communication between satellites, but this is the core part of the Starlink project. These network service requests and responses will be communicated to satellites in a vacuum environment. For high-speed communication between them, since the speed of light in vacuum is between 1.4 and 1.5 times the speed of optical fiber, if you enter this stage, you may be able to achieve a higher speed experience than the traditional physical fiber network. Here is attached Tech Vision. A video about how the Starlink project will take Internet and communication technology to the next level.

Epilogue

When inquiring about relevant information, I found that some people will define communication satellites as 6G networks, but some opponents think that it will not be the next network solution at all, so it should not be defined as 6G networks, I personally think From the current roadmap, it seems that it is impossible to achieve faster communication than optical fiber, but if a bunch of low-orbit satellites are actually sent out in ten years, then the acceleration of the speed of vacuum light will be achieved. Communication is bound to move towards the next new phase.

The convenience of the Starlink plan will make us lose something. We must know that launching a large number of satellites will actually produce light pollution. These low-orbit satellites are all visible satellites. They will reflect light and emit radio waves. These light pollution and electromagnetic waves will have a serious impact. When it comes to astronomical observations, the next generation in the future will not only see stars and moons in the sky since they were young, but will also see many satellites shuttle across the sky. I think these issues are also worth discussing.

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Original link ITechNote technology essay