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A bridge that connects the earth and the other side of the moon

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Communication from the lunar devices there is much more difficult because the far side of the moon is always facing the other side of the globe. Fortunately, relay communications satellites can act as bridges or stepping stones between transmissions from a distance to the Earth’s ground stations. credit: Space: Science and Technology

China’s Chang Chang-4 spacecraft showed the first soft landing of a spacecraft on the far side of the moon, which is always facing the other side of the globe. ground-4 relies on the eq on bridge, a relay communications satellite that orbits the point behind the moon and connects the Earth to 44, to communicate with ground stations. In a recent review, researchers described the design of Queqiao and portrayed the future of the lunar relay communication system.


Due to a phenomenon called gravity lock, the moon is always facing the same side as the earth. This proved useful in early 20th century lunar landing missions. This is because there was always an uninterrupted direct line of sight between the Earth’s ground station and the lunar equipment. However, due to gravity lock Month— Opposite — The signal is much more difficult because it cannot be sent directly across the moon to Earth.

Nevertheless, in January 2019, the Chinese lunar probe Chang Chang-4 was the first spacecraft to land on the other side of the moon. Both the lander and the lunar rover it carries have collected and sent back images and data from previously unexplored areas.But how does the Chang-4 spacecraft communicate with the Earth? The answer is the aeq bridge for relay communications. satellite, And DFH Satellite Ltd., Dr. Lihua Zhang of China explains.

As Dr. Zhang explained in a recently published review paper in Space: Science and Technology, Queqiao is an unprecedented satellite specially designed for one purpose: to act as a bridge between the Chang’e-4 probe and the Earth. Queqiao was launched in 2018 and is “behind” the Moon. I went around the point of. This point is known as the Earth-Moon Liberation Point 2, and due to the special case of gravitational balance, the Queq Bridge maintains an orbit with a nearly constant direct line of sight to both the far side of the Moon and the Earth. can do. Careful planning and maintenance was required to put the satellite into this unique orbit. The success of this operation set a precedent for future attempts to put satellites into orbit around other Earth and Moon liberation points.

From a stable location in space, the Qu Bridge assisted in the soft landing of the Chang–4 spacecraft and the guidance of ground operations, and has since acted as an intermediary for us. The satellite is equipped with two types of antennas: a parabolic antenna and some spiral antennas. The former has a large diameter of 4.2 m and was designed to transmit and receive signals in the X band (7 to 8 GHz) with a lunar rover or lander. Its large size is related to the expected noise level and the low intensity of the transmission transmitted by the ground equipment.

Spiral antennas, on the other hand, operate in the S band (2-4 GHz) and communicate with the Earth. Ground station, Transfer commands to the lunar device and exchange tracking data with telemetry. Most notably, Queqiao is extremely versatile because all these different links can send and receive at the same time. This review paper discusses other important design considerations for eq bridges and future relay satellites, such as the use of replay forwarding, various related link data rates, and data storage systems when Earth’s ground stations are inaccessible. Explains.

After two years of exploration, a large amount of data was received from the rover and lander via Queqiao. “Scientists in China and other countries have analyzed and researched on the data they have obtained and produced valuable scientific results. The longer Queqiao has been in operation, the more scientific results it will have. You get it, “says Dr. Zhang. Based on current projections, the Qu Bridge should be operational for at least five years in mission orbit.

Dr. Zhang also described the outlook for future lunar missions and how relay communication systems should evolve to support them. Many of the unexplored regions of the Moon, such as Antarctica’s largest crater, require multiple satellites to maintain a constant communication link, which presents costly and time-consuming challenges. But what if relay satellites are suitable for multiple missions? “Rather than treating each mission individually, we need to establish a sustainable communications and navigation infrastructure to benefit all lunar missions. Yes, “commented Dr. Zhang. “This infrastructure must adopt an open and extensible architecture to provide flexible, interoperable, mutually supportive and compatible communications services that are essential to the success of future lunar explorations.” Future attempts behind the moon are likely to be a test of how well we can work together to uncover the secrets of our natural satellites.


Chinese satellite announces first mission to the far side of the moon


For more information:
Lihua Zhang Development and prospects of China’s monthly relay communication satellite Space: Science and Technology (2021). DOI: 10.34133/2021/3471608

Space provided by: Science & Technology

Quote: Queqiao: The bridge between the Earth and the far side of the Moon (June 11, 2021) will be on June 11, 2021 https://phys.org/news/2021-06-queqiao-bridge-earth-side Obtained from -moon.html.

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A bridge that connects the earth and the other side of the moon

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