Hainan, Wenchang, March 20, 2023 (Xinhuanet) – On March 20, the Queqiao-2 relay satellite boarded the Long March-8 carrier rocket and successfully entered space, embarking on its journey to the moon. Once "on duty," it will establish a communication bridge spanning over 400,000 kilometers between the Earth and the moon for the ongoing Chang'e-4 mission and the upcoming Chang'e-6, Chang'e-7, and Chang'e-8 missions in Phase Four of China's lunar exploration program.
"Absolutely perfect!" Excitement was evident in the voice of Ge Ping, Deputy Director of the China National Space Administration's Lunar and Space Exploration Center, who witnessed the launch. The successful launch laid a solid foundation for the Queqiao-2 relay satellite to carry out a series of subsequent flight control missions.
Why Build a New "Magpie Bridge" Between the Earth and the Moon?
Queqiao-2 relay satellite is China's second relay satellite connecting the Earth and the moon. Named after "Magpie Bridge," a Chinese folk tale about magpies building a bridge for the Cowherd and the Weaver Girl to meet, it continues the poetic naming style of China's space program while vividly explaining the satellite's unique role: to build a bridge for "dialogue" between the Earth and the moon.
Why does the exchange of information between the Earth and the moon require a relay satellite? Experts explain that because the moon's orbital period around the Earth is the same as its rotation period, one side of the moon always faces away from the Earth. Therefore, a rover that lands on the far side of the moon cannot communicate or transmit data directly with the Earth due to the moon's obstruction. The relay satellite acts like a "router" installed in a location where the signal will not be blocked by the moon, allowing the rover on the lunar surface and the ground to communicate through this "relay station."
In 2018, China launched Queqiao, the world's first relay satellite linking the Earth and the moon, to provide relay communication for the Chang'e-4 probe that landed on the far side of the moon. As of today, the Queqiao relay satellite has been diligently working in orbit for over five years and is now in an extended service period.
The landing and sampling locations of the Phase Four lunar exploration missions are mainly in the lunar south pole and far-side regions, requiring a more capable and powerful relay satellite to establish a new "relay communication station" on the moon, addressing the communication and data transmission issues between rovers on the far side of the moon and the Earth. To this end, researchers worked tirelessly on the development of the Queqiao-2 relay satellite.
Bridging the Gap for "Chang'e"
Under the escort of the Long March-8 carrier rocket, the Queqiao-2 relay satellite successfully entered a geocentric transfer orbit with a perigee of 200 kilometers and an apogee of 420,000 kilometers, heading toward the moon.
"For Queqiao-2 relay satellite, a successful launch is just the first step. It still needs to perform key maneuvers such as mid-course orbit correction and lunar orbit insertion," said Ge Ping.
It is reported that after arriving at the moon, the Queqiao-2 relay satellite will adjust into a 24-hour period lunar elliptical frozen orbit, which is also its mission orbit. Subsequently, it will conduct communication tests with the Chang'e-4 and Chang'e-6 probes to ensure the establishment of relay communication links between the Earth and the moon, thus providing relay communication services for Chang'e-4, Chang'e-6, and subsequent missions.
"China's Lunar Exploration Cooperation Door Remains Open"
In addition to serving China's Phase-Four lunar exploration program, the Queqiao-2 relay satellite can also provide relay communication support for future lunar exploration missions, domestic and international. Currently, major spacefaring nations are actively carrying out lunar exploration activities. Regarding the highly anticipated international cooperation in lunar exploration, Ge Ping stated that China's lunar exploration program has always emphasized international cooperation, and its door remains open, as evidenced by the many successful cases and win-win outcomes in previous lunar exploration missions.
He pointed out that China has opened lunar scientific samples from Chang'e-5 to international applications. Subsequent missions in Phase Four of the lunar exploration program and planetary exploration missions will also invite international proposals for cooperative opportunities. Moreover, China was the first to propose the establishment of an International Lunar Research Station, which it has actively promoted internationally, demonstrating the格局与愿景scope and vision of China's space program.
"A new wave of lunar exploration is sweeping the globe, highlighting the importance of cooperation. China's space program cannot develop without the world, and the world's space program cannot develop without China," said Ge Ping. He emphasized that China's lunar exploration program adheres to the principles of "joint consultation, joint construction, and shared benefits" and is willing to engage in multi-level and diverse cooperation with countries and international organizations on the basis of equality and mutual benefit.
