At 17:27 on May 3rd, China’s Lunar Exploration Program celebrated another successful venture as the Chang’e-6 lunar probe was launched from the Wenchang Space Launch Site aboard the Long March 5 Y-8 carrier rocket, successfully entering its preset orbit.
△ The Long March 5 carrier rocket lifting off in the rain (Photo by Su Dong)
The Chang’e-6, as the kickoff probe for phase four of the lunar exploration project, is set to achieve the first-ever sample return from the far side of the moon. The area selected for sample collection is the South Pole-Aitken Basin—the largest impact crater in the solar system—located on the lunar far side—a veritable “mystery” to be explored.
The journey to the moon is long and taxing. The “super rocket” Long March 5, which carried the Chang’e-6, was well-equipped, sporting 30 engines to help the probe conserve energy. It provides a great display of Chinese space engineering prowess, with the China Aerospace Science and Technology Corporation deploying 107 engines—77 on Chang’e-6—for this mission.
Short Interval between Long March 5 Y-6 and Long March 5 Y-8 Missions
Between the moment the rocket lifted off and the probe’s “orbital braking” near the moon, to its landing on the lunar far side, every stage was full of new challenges. Chen Jianhua, Deputy Chief Designer of the Long March 5 series carrier rockets, stated that the Long March 5 series will execute high-density launches over the coming years. With this mission, the preparation time between the Y-6 and Y-8 launches was just two to three weeks. This pace tested the Aerospace Science and Technology Corporation’s rapid-fire mission capability and highlighted the maturity of liquid rocket engine technology and the feasibility of executing high-density launch missions.
Relay Feat by 77 Diverse Engines Forming the “Space Transport Team”
Chang’e-6, in its 53-day mission to go beyond capturing just images of the moon’s mystery-shrouded far side but also bring back hitchhiking “lunar souvenirs”, faced unprecedented challenges and high risks. Every movement was precise, and every operation carried the weight of high expectations from billions of people.
The Chang’e-6 probe is one of the most complex spacecraft systems that China has developed so far. Among its intricate systems are three orbit control engines, 74 attitude control engines, and additional equipment like tanks, gas bottles, valves, wire boxes, and pressure sensors. With this dense and diverse motorized propulsion force, Chang’e-6 can perform a series of challenging maneuvers in space.
Hong Xin, Deputy Chief Designer of the Chang’e-6 probe system, said, “These 77 engines, of varying sizes and capabilities, have created a ‘logistics’ channel in space, performing different functions in a relay manner to complete the mission. They truly are the ‘space transport team.'”
Tackling High Temperatures of About 120℃ While Working on the Lunar Surface
The Chang’e-6, being the initial probe of the fourth lunar exploration stage, demanded lighter weight and higher performance propulsion systems than its predecessors. These requirements challenged the team to improve the propulsion subsystem to adapt to an environment that previous propulsion systems had not encountered: enduring high temperatures of about 120℃ while working on the lunar surface. With typical resolve, the development team modified the interface structure of the engine’s electromagnetic valve and thrust chamber to enhance its high-temperature resistance. This determination and hard work once again demonstrated the stability, reliability, and adaptability of the project.
The Chinese probe’s journey to the moon signifies a romantic and daring venture, much like the legendary moon goddess Chang’e. This contemporary moon mission brings us closer to converting legend into reality. Today, as we celebrate 20 years of the “Chang’e Project”, we bear witness to countless successful ventures to the moon and beyond—an exciting journey that began in earnest on 23 January 2004.
Contributed by Ma Huzhen of Huashang Daily Dafeng News (Photos by the Aerospace Science and Technology Corporation)