China to build lunar constellations to support ground operations

China plans to deploy several satellites around the moon to provide communications and navigation services to support its future ground operations. The first system could be deployed in 2024.

China has made great strides in space recently, especially on lunar terrain, but it doesn’t plan to stop there.To support its increasingly complex operations, the country is counting on the deployment of a satellite constellation in lunar orbit. The first launch could take place in 2023 or 2024, according to Wu Yanhua, deputy administrator of the China National Space Administration. Other countries are also welcome to join the project.

No other details were provided, but China’s lunar roadmap still gives us some clues.

Chang’e 6 and Chang’e 7

As far as we know, these communications and navigation relay satellites can initially support Chang’e-6 and Chang’e-7 sample return missions, which includes sending an orbiter, lander, rovers and small spacecraft capable of surveying shadowy craters around the site. These missions could start in 2024 or 2025.

China already has a relay satellite, but it’s parked Around Lagrange Point 2, about 1.5 million kilometers from Earth. The latter facilitates communications with the Chang’e-4 lander and the Yutu-2 rover, stationed on the far side of the moon.

However, we do know that Chang’e 6 and Chang’e 7 should aim to approach South Pole of the Moon. Therefore, satellites in different orbits are needed to transmit large amounts of data between the Earth and the south pole of the moon.

For example, the relay satellite concept to support the Chang’e 7 mission would freeze the orbit using a steep elliptical inclination with a near-moon (closest point) of 300 km and an apoluna (farthest point) 8,600 km and a slope of 54.8 degrees. According to Spacenews, such a configuration would allow a communication link between Earth and the moon’s south pole for more than eight hours in its roughly 12-hour orbit. Adding more satellites in similar orbits will provide consistent communications and navigation coverage.

The moon and the distant Earth as seen from the Earth-Moon Lagrange 2 o’clock by the Queqiao relay satellite.Credit: Zhejiang University

Towards permanent human existence

Other missions will follow.For example, Chang’e 8 will be designed to test 3D printing technology and resource usage in situ. At that time, China will cooperate with Russia to establish a lunar research station. The project will build a robotic facility Perpetual between 2030 and 2035. Once completed, the base could support human presence in the long term.

As a result, China’s lunar communications and navigation constellation is likely to be built incrementally, providing more and more capabilities as its lunar program progresses.

Note that NASA, the European Space Agency, and other private companies are also planning lunar communications and navigation infrastructure to support the Artemis lunar exploration program.

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