The target has launched 42000 satellites, and the US satellite chain has fired its first shot. Can it really serve the world?

Recently, according to media reports, SpaceX company of the United States announced that it has successfully launched and deployed the tenth batch of satellite chain satellites, with 595 satellite chains, becoming the world’s largest commercial satellite network owner. The company’s goal is to launch 42000 satellites and establish a space-based communication system covering the world. Some analysts believe that the United States Satellite chain has fired the first shot, and it will be connected in the future The trend of the letter will have a significant impact. Some netizens have doubts about it. Can it really serve the world? Satellite link satellite is actually a communication system operating in low orbit. Its principle is similar to the iridium satellite project proposed by Motorola in the 1990s. However, the former provides broadband network services, while the latter provides narrow and wide voice services. Similar to previous satellite TV, Motorola’s plan was stranded because of GSM network in the 1990s It is very mature, and with constant losses, it announced the termination of service in 1999. < p > < p > at present, the commercial communication network is mainly land-based telecommunications. From GSM to 5g, the transmission rate is faster and faster. For 5g, the delay rate is only 1ms, and the download rate is as high as 1gbs, which is 100 times faster than that of 4G. However, the delay of satellite link satellite is 15ms to 20ms, which is equivalent to the level of broadband. In addition, the frequency band used by satellite link satellite is different from that of mobile phone, Therefore, if a mobile phone wants to receive the network, it must have a special receiver to receive the signal, then convert the signal, and then send it to the mobile phone, which is a very complicated task. < / P > < p > in addition, satellite signals can not penetrate buildings such as steel and cement, so it is necessary to install an antenna on the roof, which can not be blocked by trees and other obstacles. In addition, it is easy to be affected by climate. Once thunderstorm weather occurs, it is likely to block the signal transmission. What’s more, the design bandwidth of a single satellite in the satellite chain is 17-20gbps, even 42000 satellites All satellites are deployed, and the total bandwidth is 840000 Gbps. If calculated according to the 5g entry standard, 1Gbps, it can only be used by 840000 users at the same time. If it is reduced to the 4G standard of 100Mbps, it can not be popularized. The global Internet users have exceeded 4 billion. If you want the star chain to provide global services, you can only go back to the GSM era. < / P > < p > although the satellite link can not be compared with land-based telecommunications, it also has certain feasibility. First of all, it is in a very low orbit, which is in the range of 340 km to 1300 km. Compared with the 6000 km geosynchronous satellite, the launch cost is relatively low, and it can make up for some defects of land-based telecommunications. However, due to the limited bandwidth, satellite chain satellites can only be used for special purposes In the field of consumption, it is impossible to have a foothold in the field of consumption, because 5g has been widely commercialized, and 6G has begun to develop. Without a fundamental technological breakthrough, star chain simply does not have the ability to provide global services. < / P > < p > although the United States put the star chain on the stage, it only provides the world with a direction of thinking and can not change the current reality of telecommunications, but the emergence of new things always has its feasibility in some aspects. Therefore, we should learn from them, face up to the limitations and advantages, and then derive new technologies. Science Discovery