In this era, the concept of satellite communication networks is not yet very mature.
The common communication method still relies on ground transmission towers and various cables for relay connections.
This method of communication certainly has the advantage of stable connection, but because it requires the construction of a huge number of ground base stations and communication cables, the infrastructure investment required is actually very large.
At this time, the most commonly used communication method among people in China was landline telephones, and very few people had access to mobile phones.
Therefore, everyone actually has little demand for mobile communications.
However, just because there is no such demand now does not mean that there will not be such demand in the future.
Later, in just two decades, China became the country with the most mobile devices in the world. The demand for this is actually very large.
Therefore, out of precautionary considerations, it is necessary to plan the construction of low-orbit satellite communication networks now.
Generally speaking, the distance between 100 kilometers and 300 kilometers from the earth's surface is low orbit. The service life of satellites operating in these orbits is generally not very long, because they are affected by the earth's gravity and will continue to fall to the surface. Fuel is used continuously to maintain orbital altitude.
Low orbit has many benefits for satellite communications, the biggest of which is reduced costs.
For example, the orbital altitude of the Iridium satellite is about 800 kilometers, while the altitude of the new generation of low-orbit communication satellites is basically about 300 kilometers.
This places lower thrust requirements on the rocket, and the number of satellites that can be launched at one time is also greatly increased.
For example, the Long 3B rocket that made its first flight this year has a carrying capacity of 5.65 tons for an 800-kilometer orbit and 10.82 tons for a 300-kilometer orbit.
This means that the launch cost of a low-orbit satellite is half that of a high-orbit satellite.
Of course, no one in China except Zhang Xingyang is really aware of the commercial and military uses of low-orbit communication networks.
But this does not prevent Zhang Xingyang from instilling his ideas in others.
"Mr. Chen, what do you think the form of network communication will be like in the future?"
This is a symposium on the eve of the establishment of the Domestic Internet Network Information Center, discussing various issues of the future Internet.
Although Chen Zhongyan is the chief engineer of Beidou Navigation, it does not mean that he does not understand the development of the Internet. On the contrary, he knows it very well.
"The future network communication method will definitely be to access user equipment through wireless transmission. As for whether to use ground base stations for signal coverage or satellite networks for signal coverage, it is difficult to say."
"Xiao Zhang, what do you think?"
The two of them came to attend this meeting more as observers. After all, the country has been preparing for the establishment of the Internet Network Information Center for several years, and the preparations in all aspects have actually been completed.
Therefore, the two of them still like to talk about something that is more focused on their majors, the aerospace field.
"Mr. Chen, these two methods actually have their own advantages, but I personally prefer the low-orbit satellite network method."
"Oh? Tell me your reasons."
Chen Zhongyan became a little interested because he felt that Zhang Xingyang seemed to have his own unique insights.
"The only satellite communication network currently used in the world is the global telephone service launched by Iridium this year."
"But because the actual number of communication satellites they use is only 66, although they can cover the entire world, the amount of data that a single satellite can access at the same time is very low, and it is impossible to meet the huge amount of data after the advent of the Internet era."
"So if we want to truly connect to the Internet through satellites in the Internet era, the only way we can really use it is to launch a large number of small satellites in the earth's low orbit for network communications."
Chen Zhongyan did not expect Zhang Xingyang's ambition to be so big, because if this method was really adopted for network construction, the construction cost would definitely be much higher than using ground base stations for networking.
"Xiao Zhang, have you ever thought about such cost issues and subsequent maintenance issues?"
Chen Zhongyan frowned and expressed his opinion. He did not particularly agree with Zhang Xingyang's idea.
"Mr. Chen, the cost is actually not as high as you think."
"Huh? The cost of rocket launch alone is a lot, not to mention the cost of satellites."
As the chief engineer of the Beidou Navigation System, Chen Zhongyan is naturally not an outsider. He knows that the cost issues here are mainly concentrated on satellites and rockets.
However, he did not know that the Rocket Research Institute had been busy this year with the research process of new rocket engines and new recyclable rockets, otherwise he would not have had such concerns.
"Don't worry about this. Our research institute is currently developing a high-thrust liquid oxygen kerosene engine that can meet the requirements of multiple recycling uses."
"If recyclable rockets are used, the cost of launching satellites will be reduced to a very low level. It is expected that the launch weight of one kilogram will not exceed 5,000 yuan."
"As for the satellite issue, we don't need one generation of satellites like Iridium to be used for more than ten years. This actually makes its satellites expensive and difficult to replace."
"The designed service life of the satellite is only one to two years. This not only reduces the production cost of the satellite, but also makes it more convenient for future upgrades."
Chen Zhongyan thought in his heart that if what Zhang Xingyang said was true, then the low-orbit satellite network could still be tried.
I just don't know if what he said is true. After all, Zhang Xingyang is too young. According to ordinary people's thinking, he can't do things well if he doesn't talk well.
Although Zhang Xingyang has accomplished a lot since he took over the institute, he still has not accumulated enough prestige for people to have faith in him.
"Mr. Chen, let me do some math for you. In the initial stage of building a domestic satellite communication network, it will take about four thousand low-orbit satellites to be launched."
"The new generation of recyclable rockets we designed can launch about 26 tons of payload to an orbit of 300 kilometers at a time. Assuming each rocket weighs 250 kilograms, then 104 satellites can be launched into space at a time."
"Calculated this way, four thousand satellites only require forty rocket launch missions to complete."
"If recyclable rockets are used, even if each rocket is reused only five times, only eight rockets will be needed to complete the entire launch mission."
"Even if you can only recover the first stage of the rocket, you can save a lot of money, and our rocket uses liquid oxygen kerosene as fuel, which is cheap."
"Taken together, the cost of establishing a low-orbit satellite network is actually much cheaper than building thousands of ground base stations."
Zhang Xingyang carefully calculated the cost for Chen Zhongyan.
At this time, Chen Zhongyan realized that he seemed to be convinced by him and laughed:
"Xiao Zhang, what you said is very good, but when will we be able to build our rocket?"
"The country cannot have that much time to wait for you!"
"Although I also hope that this system can be established, the technical difficulties are still quite large in the short term."
Technical issues are the least of Zhang Xingyang's concerns. What he needs is more policy tilt and funding.
"Mr. Chen, our rocket will definitely be tested within next year, and we will never let the country wait for us!"
Seeing Zhang Xingyang who was almost issuing a military order, Chen Zhongyan was also a little curious about how far he could go:
"Okay, I will talk to the superiors about my ideas in this regard, but if you want to really realize this, it still depends on the progress of your rocket development."
