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China-Singapore Net Sea, December 17 Title: Chang’e 5 moon “punch card” return orbiter “ferry” the way home
Author Zheng Yingying Guo Chaokai
In the early morning hours of December 17 Beijing time, returnee Chang’e-5 brought lunar samples back to Earth. China’s first lunar surface sampling and automatic return mission was a complete success. In the process, the orbiter developed by the China Eighth Academy Aerospace Science and Technology Corporation, as a “space postman”, escorted Chang’e-5 back to Earth.
“Space Porter” with a belly on his head
The Chang’e-5 probe is a four-vehicle assembly design, consisting of four parts: a lander, an ascendant, an orbiter, and a return. Among them, the return, lander and ascendant have the basis for the development of the first and second phases of manned spaceflight and lunar exploration projects, and the development of the orbiter can be described as “made from scratch” . According to the mission requirements, the Chang’e-5 orbiter, which has more than 1 ton of its own, requires a 3.7 ton landing and climb mount “at the head”, with 3 tonnes of propellant and more. 300 kilograms of returnees, who are separated in sequence during the flight. The landing and climb assembly, sample docking and transfer mechanism and return also make the orbiter China’s first lunar exploration vehicle with “high payload” and “multiple separation surfaces”.
To achieve the goals of configuration optimization and weight reduction, the developers of multiple systems such as general, structural and thermal control have demonstrated more than 10 configurations and finally inherited the large configuration of the outer propulsion support tube of the spacecraft. Shenzhou. , Innovatively proposed the “three-cabin configuration plan” of the support cabin, the docking cabin and the propulsion instrument cabin, realizing the independent transmission of the two routes of “up” and “in the belly” , greatly improving the efficiency of structural loading; making the support cabin The docking cabin is “dedicated to special cabins” and “throw it away after use” to make way for its follow-up missions, reducing its quality and saving propellant.
The diligent “luggage transfer”
After the successful sampling of the Chang’e-5 lander and ascendant combination, the ascendant carrying the lunar soil cannot use its own energy to return to Earth. The cargo must be delivered in the form of “space logistics”.
The key to the fluidity of “space logistics” depends on “meeting and docking.” On the International Space Station, the docking mechanism is used primarily for mounting larger tonnage aircraft. The scientific name for the coupling mechanism used in manned space flights is the peripheral coupling mechanism with different body and isomorphism. After docking, a channel can be formed to facilitate the passage of astronauts. Unlike manned spaceflight docking mechanism, the Chang’e-5 probe adopts claw-type docking mechanism, which is made up of 3 sets of K-shaped claws. Tighten it to achieve a firm connection between the two devices. .
On the way back from Chang’e-5, the ascendant and orbiter completed the first lunar orbital encounter and docking, and the precious “package” of lunar soil samples was transferred to the returner. The orbiter is like a “postman” orbiting the moon. After diligently completing the “packing” and “boxing”, it quickly enters the lunar earth transfer orbit to perform airdrops and carry the lunar soil samples back to the blue planet.
The challenging “Lunar Rail Transfer Road”
How difficult is this “match and match”? Zhang Yuhua, deputy commander-in-chief of the Chang’e-5 probe, said: “It can be said that the world’s first lunar orbit unmanned encounter and docking plays a decisive role in the success or failure of this mission. “. He presented that, from the perspective of the tasks of finding, docking and transfer of samples, reliability is the most demanding, because the whole process can only be successful once and there is no second chance. To ensure its reliability, the coupling and sample transfer mechanism has made multiple redundancies. Only the coupling verification test has been simulated thousands of times on the ground. At the same time, the lunar orbit is lagged relative to the Earth’s orbit, and the temporal corridor is small, requiring very high punctuality. The Moon Orbit Encounter and Docking Mission must complete in 21 seconds, capture in 1 second, correct in 10 seconds, and lock in 10 seconds. The sample transfer task has many interfaces, many links, and the process is complicated.
Zha Xuelei, the deputy chief designer of the Chang’e-5 probe, said: “The orbiter’s docking and sample transfer mechanism came out of nowhere. After 10 years of research and development, manufacturing and testing, it finally embraced the ascendant with a solid arm, The sample container was transferred carefully, which was an extremely important part of the Chang’e-5 “sample return.
In the world’s first unmanned rendezvous and docking in lunar orbit, automatic control is adopted from start to rendezvous and docking. Liu Zhong, deputy director of the sample docking and transfer subsystem, said that to ensure the smooth completion of the task, the team made 35 failure plans, but none of them were helpful. This is the best result. (End up)
