Can the "Starlink Model" compete with Starlink? Opportunities and challenges for the development of my country's satellite Internet

As an effective supplement to ground mobile base stations and fiber optic networks, satellite Internet can cover areas and scenarios that are difficult to reach with traditional communications. It is a key link in building an integrated network of air, land, and sea in the future 6G system. In 2020, my country included satellite Internet in the communication network information infrastructure of the "new infrastructure" for the first time at the policy level, clarifying its major strategic significance. In 2022, the "Starlink" system played an important role in a certain battlefield command system, once again confirming that the development of satellite Internet is imminent.

Starlink system

The development of satellite Internet began in the 1980s and has gone through three major stages: before 2000, it was mainly narrowband communication, mainly low-speed voice services; from 2000 to 2014, it was also narrowband communication, with low-speed voice and data services; after 2014, it was mainly broadband Internet, with high speed, low latency and massive data as its main features. The more representative constellation is the US "Starlink" system.

The Starlink system is a satellite Internet project launched by SpaceX in the United States in 2015. It plans to deploy 12,000 low-orbit satellites between 2019 and 2024 and 42,000 by 2027[1], forming the world's largest giant constellation network to provide high-speed, low-latency Internet access covering the world. Its original intention was to provide Internet services worldwide, especially in remote areas that are currently inaccessible to the Internet. To date, Starlink has launched more than 4,600 satellites[2] and has provided related services to at least 46 countries and regions[3]. In actual tests, its maximum download speed reached 400Mbps, the maximum upload speed was about 18Mbps, and the delay was only 27ms, which is significantly better than traditional satellite Internet access services[4]. In 2022, a command system integrated Starlink equipment for information transmission, intelligence collection and drone control to ensure that even if the wired network is destroyed, it can still build an internal communication network and achieve uninterrupted command[5].

Competition for satellite internet resources

The construction of satellite Internet requires a certain number of satellites. For satellites, orbital and frequency band resources are scarce resources, and the international practice is usually "first come, first served".

For satellite orbits, there are high orbits (GEO), medium orbits (MEO), low orbits (LEO), etc. Among them, although the coverage capability of a single satellite is weaker than that of GEO and MEO orbits, wide-area seamless coverage can be achieved through constellation networking, and its link loss and transmission delay are the smallest (within 10ms), and the processing capability requirements of the terminal are also low, which is more suitable for the requirements of future satellite Internet. The first phase of the "Starlink" system constellation consists of 4408 satellites with an orbital altitude of about 550KM, and the second phase constellation consists of 7518 satellites with an orbital altitude of about 340KM. The 30,000 satellites planned to be launched by the third phase constellation all use LEO low orbits. It is estimated that the Earth's LEO orbit is expected to accommodate about 60,000 satellites, and "Starlink" satellites will soon occupy most of them, which has triggered a fierce competition among space powers[6]. During the 13th Five-Year Plan period, my country proposed low-orbit satellite Internet plans such as "Hongyan" and "Hongyun", with only more than 400 satellites; in April 2021, my country established China StarNet Company, which specializes in the design, construction and operation of satellite Internet. Its constellation plan "StarNet Project" is expected to launch 12,992 low-orbit satellites (6,080 satellites with an orbital altitude of 500-600KM, and 6,912 satellites with an altitude of 1,145KM) to build a huge constellation system.

As for frequency band resources, C, KU, KA and other frequency bands are commonly used in satellite communications: C band is mostly used in geostationary orbit, with low frequency, low gain, large antenna size, strong anti-interference ability, stable transmission channel, and currently available resources are saturated; KU band has high frequency, high gain, small antenna size, and is convenient for receiving equipment to use. It is the golden band for satellite communications, and available resources are relatively saturated; KA band has a higher frequency and a larger band bandwidth. It is the golden band for high-speed satellite communications, and available resources are also relatively saturated. The frequencies occupied by the "Starlink" system are mainly distributed in the two golden bands of KU and KA, and the three-phase constellation uses the higher E band. In September 2020, my country's "Starnet Project" submitted the frequency allocation file of the "GW" broadband constellation plan to the International Telecommunication Union (ITU). The transmission bands are mainly distributed in the KA band and the higher frequency V band.

Despite this, many of our satellite internet constellation projects are currently in the initial testing phase, and there are still some unresolved problems. However, the battle for resources has not slowed down, and space powers are catching up. Therefore, we still have a long way to go.

Development Inspiration

As the world's largest and most technologically advanced constellation, the Starlink system has played a good role in many scenarios such as communication and remote sensing, but it also has many problems that are worth learning from.

First, it is easy to pose a threat to other spacecraft. Since the Starlink system was put into operation, it has had many close encounters with EU spacecraft and China's space station. The main reason is that the deployment of Starlink satellites is not "all in one step", but is first sent to a very low orbit, and then propelled to the target orbit by its own power. Due to the use of weak Hall electric propulsion technology, it is difficult to adjust its attitude in time when encountering other spacecraft during the propulsion.

Second, the low orbit leads to a significant increase in maintenance costs. In order to increase the capacity of the Starlink system, the orbit of the system has been reduced from the original 1,150 km to 550 km and 340 km (there is air in the atmosphere below 600 km), which has a certain operating resistance and the satellite must frequently adjust the orbital altitude; therefore, although the satellite is designed to have a lifespan of 7 years, the average lifespan is only 5 years. Therefore, after the Starlink system is deployed, 20% of the satellites (about 8,000 satellites) need to be added each year, which greatly increases the maintenance cost of the constellation.

Third, the intersatellite link technology increases the link transmission performance. The "Starlink" satellite has gone through several versions: V0.9 (weight 227KG), V1.0 (weight 260KG), V1.5 (weight 277KG), and now V2.0 (weight 1.25T); starting from V1.5, "Starlink" uses intersatellite laser links, which greatly reduces the dependence on ground networks and signal gateways, reduces the complexity of the ground segment of the system, and at the same time, the relay transmission of the space segment has a great optimization effect on information transmission loss and delay.

In the development of satellite Internet, the United States has always been at the forefront of the world and has also taken many "advances" in the competition for resources. We hope to gain some thoughts on the development of my country's satellite Internet through analysis and learning. In addition, the new version of "Starlink" satellites has become significantly larger, which undoubtedly increases its ability to expand its functions. In the future, "Starlink" may no longer be a simple commercial communication system. It is expected that its future military applications will become more and more aggressive. Therefore, the development of our satellite Internet is urgent.

References

[1] Baidu Encyclopedia: Starlink, https://baike.baidu.com/item/%E6%98%9F%E9%93%BE/15519513?fr=ge_ala, April 27, 2023.

[2] SpaceX Falcon 9 rocket successfully launches 47 Starlink satellites, "Space Window" (539), https://mp.weixin.qq.com/s/xZt6XwLtBI3CFNYDNCiwtw, June 24, 2023.

[3] Global Space Mission Outlook in 2023: SpaceX’s number of satellites in orbit exceeds 4,000, and Starlink broadband has now entered 53 countries, with over 1 million subscribers, https://www.shangyexinzhi.com/article/7985588.html, May 7, 2023.

[4] What is so great about Starlink? https://baijiahao.baidu.com/s?id=1754501993603071083&wfr=spider&for=pc, January 9, 2023.

[5] Xinhuanet: “Starlink” is launched and the “Star Wars” have begun: What are the military uses of the Starlink program? January 18, 2022.

[6] White Paper on the Development of China’s Satellite Internet Industry under the “New Infrastructure” Initiative, May 29, 2020.

Author: Sang Jinxin

Unit: China Mobile Smart Home Operation Center