Chinese scientists have made multiple technological improvements for the Long March-5B carrier rocket, thus ensuring the successful launch of the first group of low Earth orbit satellites for a satellite internet constellation.
At the Wenchang Space Launch Site in southern Hainan Province on Monday, the group of satellites was launched by a Long March-5B carrier rocket with a Yuanzheng-2 (Expedition-2) upper stage atop the rocket. The satellites have entered the preset orbits.
As the first multi-satellite launch for the Long March-5B carrier rocket, the mission places high demands on separation technology for satellites.
"To address this problem, we have developed a new type of capture buffer device, which functions as a shock-absorbing buffer during the separation process. It can significantly reduce the impact load environment and ensure the successful completion of this mission," said Zhu Haiyang with the China Aerospace Science and Technology Corporation (CASC).
For this mission, the rocket underwent 20 technological improvements, further enhancing its adaptability and reliability.
The multi-satellite launch mission requires the rocket to deliver each satellite to its own designated point, which is fulfilled with the help of the Yuanzheng-2 upper stage.
Just like a ferry to transport passengers, the upper stage, assembled with their passengers -- satellites, is sent to a designated position by the rocket at first, and then deliver satellites to their desired destinations after a long-duration flight.
"The upper stage can carry multiple passengers, which allows it to save fuel for the satellites during the orbital insertion process and shorten the orbital insertion period. This enables the satellites to enter orbit more efficiently and quickly for operation," said Zhang Xinyu with the CASC.
The Yuanzheng-2 is China's largest liquid-fuel upper stage with the strongest capability for orbit transfer.
As early as 2016, the integration of Yuanzheng-2 with Long March-5 carrier rocket sent Shijian-17, a satellite for verifying new technology in geostationary orbit, into its designated orbit, marking the successful completion of the Long March-5 rocket's maiden flight mission.
In addition, the Long March-5B rocket is equipped with a fault diagnosis and handling system for the first time, making the rocket smarter and more reliable.
"Once its condition is diagnosed, its remaining capabilities can be further evaluated to determine which orbits it can still reach and reprogram the flight profile, thus greatly enhancing flight reliability of the Long March-5 series rockets, and also supporting the intelligent upgrades for the next generation of carrier rockets," Zhu said.
Multiple technological improvements permit successful launch of satellite group
China is accelerating efforts to build low-altitude infrastructure, with new takeoff and landing facilities, communication networks, and digital systems being constructed in key cities to facilitate the development of this rapidly growing sector.
Low-altitude economy refers to the economic activities and industries centered around manned and unmanned aerial vehicles operating in the airspace usually within 1,000 meters above the ground.
In southern tech hub of Shenzhen, a newly operational rooftop helipad is a key part of the city's push to expand its low-altitude economy. Originally built for fire safety, the helipad has been repurposed with plans for a new aerial sightseeing route in the surrounding area.
"We've estimated the investment, and it's relatively modest since the foundational infrastructure is already in place. The costs will likely be in the range of a few million yuan. If rooftop helipads are connected, it could create an aerial transportation network that links different buildings together," said Kuang Hu, vice chairman of Guangdong Yuehai Land Group.
Shenzhen aims to complete over 1,200 low-altitude facilities by 2026, with the local government offering subsidies of up to 2 million yuan (over 270,000 U.S. dollars) per project. These efforts are part of a broader strategy to create a seamless low-altitude infrastructure ecosystem that integrates airspace management, flight paths, and services.
"By the end of 2026, the district aims to complete 100 low-altitude infrastructure projects," said Chen Wenlei, deputy director of the Development and Reform Bureau of Luohu District, Shenzhen.
"We are in the process of establishing a comprehensive network that includes infrastructure, airspace management, flight paths, and services. By integrating these four key networks into a unified low-altitude standard system, we aim to promote the seamless opening and integration of low-altitude airspace infrastructure and systems," said Cheng Tao, executive secretary of the Shenzhen Low-altitude Economy Industry Association.
In Shanghai, the East China UAV Base has been approved for testing new drones, technologies, and services within a 1,370-square-kilometer airspace. A newly deployed 5G base station at the base offers both communication and radar-like sensing capabilities, essential for managing low-altitude airspace.
"Currently, the station covers a radius of several kilometers, offering crucial data such as the aircraft's latitude, longitude, altitude, speed, and other key metrics. Once airborne, all types of aircraft require communication. For those flying below 300 meters, we can provide tailored coverage for their flight paths," said Du Yanyan, deputy general manager of the Planning and Technology Department at China Mobile Shanghai.
Experts say that technologies like 5G and the BeiDou navigation system are essential to supporting China's low-altitude infrastructure. However, they emphasize the need for network interoperability to address challenges as drones and aircraft transition between regions.
"The low-altitude communication and sensing networks being developed in various regions each follow different technical approaches. For example, when a drone travels from Area A to Area B, it must switch networks, and addressing these challenges promptly is crucial," said Du Jiadong, head of the network and application group at the Low-altitude Economy Research Center, China Academy of Information and Communications Technology (CAICT).
The Civil Aviation Administration of China estimates that the country's low-altitude market will soar from 500 billion yuan in 2023 to 1.5 trillion yuan in 2025 and as much as 3.5 trillion yuan in 2035.
This year, for the first time, the term "low-altitude economy" was included in the Chinese government's work report, signifying an official endorsement that has emboldened numerous cities.
Infrastructure networks rapidly taking shape to boost low-altitude economy
