The successful launch of the fourth phase of lunar exploration by the Magpie Bridge II relay satellite will lead to the construction of a new "Magpie Bridge" on the Earth and Moon

At 8:31 am on March 20th, the fourth phase of the lunar exploration project, the Queqiao 2 relay satellite, was successfully launched from the Wenchang Space Launch Site in China by the Long March 8 Y3 carrier rocket. As a crucial link in the follow-up project of the fourth phase of lunar exploration, the Magpie Bridge II relay satellite will establish a new "Magpie Bridge" between the Earth and the Moon, providing relay communication between the Earth and the Moon for missions such as Chang'e-4 and Chang'e-6.

After 24 minutes of flight, the Long March 8 Yao 3 carrier rocket separated from the rocket and directly launched the Queqiao 2 relay star into the scheduled Earth Moon transfer orbit with a perigee altitude of 200 kilometers and an apogee altitude of 420000 kilometers. The relay star's solar wings and relay communication antennas were deployed normally, and the launch mission was a complete success. Subsequently, with the support of ground measurement and control, Magpie Bridge 2 will undergo intermediate corrections and near moon braking to enter the capture orbit; Subsequently, after orbital control, it entered a phase modulation orbit and finally entered a 24-hour lunar mission orbit, becoming the world's second dedicated relay star outside Earth's orbit after the Magpie Bridge relay star. It provided support for the lunar sampling mission of Chang'e-6 and relayed communication services from the Magpie Bridge relay star to Chang'e-4.

Due to one side of the moon always facing away from Earth, the probe landing on the far side of the moon is obstructed by the moon itself, making it unable to directly achieve measurement, control, communication, and data transmission with Earth. The landing exploration and sampling locations for the fourth phase of the lunar exploration project are mainly located at the South Pole and far side of the Moon. Therefore, a more versatile and powerful relay star is needed to establish a new "relay communication station" from the Moon to the Earth, to solve the communication and data transmission problems between the lunar far side probe and the Earth. Based on this, researchers have made arduous research and development on the Queqiao 2 relay satellite, aiming to provide relay communication services for the operational Chang'e-4, upcoming Chang'e-6, Chang'e-7, Chang'e-8, and subsequent domestic and international lunar exploration missions.

Compared with the Chang'e-4 "Queqiao" relay satellite launched in 2018, the Queqiao 2 relay satellite has more technological innovation, more technological status, stronger functions, more complex interfaces, higher development difficulty, and a longer mission time span. In addition, Queqiao 2 carries multiple scientific payloads and will carry out scientific exploration.
The Long March 8 Yao 3 rocket adopts a two-stage and a half configuration with two liquid boosters tied to the core stage, with a total length of 50.3 meters. This mission is the first lunar exploration orbit launch mission carried out by the Long March 8 carrier rocket. The development team has made design improvements and optimizations to the rocket based on mission requirements such as multi window and multi trajectory, low altitude and high-speed flight profiles, expanding its mission adaptability and improving reliability. This time, Tiandu 1 and Tiandu 2 navigation technology test satellites were also launched. This is the 512nd launch of the Long March series of carrier rockets.
In December 2021, the fourth phase of the lunar exploration project was approved for implementation, consisting of four missions: Chang'e-4, Chang'e-6, Chang'e-7, and Chang'e-8. Chang'e-4 was launched in December 2018, achieving the world's first soft landing survey on the far side of the moon; Chang'e-6 will be launched at an appropriate time in the first half of 2024; Chang'e-7 and Chang'e-8 will build basic lunar research stations and carry out tasks such as lunar environmental exploration.
The lunar exploration project is organized and implemented under the leadership of the National Space Administration. In this relay satellite mission, the overall project is undertaken by the Lunar Exploration and Aerospace Engineering Center; The relay satellite and carrier rocket are jointly developed by the China Academy of Space Technology and the China Academy of Launch Vehicle Technology of China Aerospace Science and Technology Corporation; The ground application system is undertaken by the Chinese Academy of Sciences. (Text: Cai Jinman, Zhang Wei, Li Yi Image: Zhang Gaoxiang Video: Zhang Zihan, Niu Dali, Li Xiang)