At 4:30 am on November 24, 2020 Beijing time, China’s Long March 5 carrier rocket was launched at the Wenchang Space Launch Site in Hainan, carrying China’s Chang’e-5 lunar probe.
This is the first time the lunar sample return mission has been carried out, and it is also the most complicated space mission carried out by China so far.
It is reported that this space mission has 11 major flight phases, 23 major orbital control, 6 major separation control and other complex links, as well as spacecraft lunar landing, lunar take-off, and "unmanned rendezvous and docking" in lunar orbit. The entire sampling and return process takes up to 23 days, and the launch is only the first step in the long process.
The Long March 5 rocket is currently the most powerful rocket in China. The carrying capacity of low-Earth orbit is 25 tons, the carrying capacity of ground-fire transfer orbit is 6 tons, and the carrying capacity of earth-moon transfer orbit is 8.2 tons.
Previously, the Long March 3A rocket, the Long March 3C rocket, and the Long March 3B rocket undertook the mission of launching China’s lunar probes, and successively launched the four moons mission of Chang’e 1, Chang’e 2, Chang’e 3 and Chang’e 4. The probe completed the orbit detection, landing detection and patrol detection of the moon.
On July 23, 2020, the Long March 5 carrier rocket also successfully launched the "Tianwen-1″ Mars probe, which is currently on its way to Mars.
China’s lunar exploration project is the first lunar exploration project launched by the country. It was officially launched on January 23, 2004. It is divided into three parts: orbiting, landing, and returning.
1. "Orbiting" means launching lunar satellites. Chang’e-1 and Chang’e-2 have been reached this objective.
2. "Landing" means a soft landing on the surface of the moon. Chang’e-3 has achieved a soft landing on the front of the moon, and "Chang’e-4″ has also achieved a soft landing on the back side of the moon, and scientific exploration work has been carried out on the back of the moon, which is a first for the world.
3. "Returning" means to sample from the surface of the moon and return to the earth. This is the mission carried out by Chang’e-5, which plans to bring 2 kg of lunar soil samples back to earth.
It is worth mentioning that, China has expanded the mission of the "Lunar Research Station". The mission is completed by the subsequent "Chang’e-6″, "Chang’e-7″ and "Chang’e-8″ with plans to land on the lunar south pole and conduct more complex scientific research.
So far, only two countries have successfully brought back samples from the moon: the United States and the former Soviet Union.
Among them, in the 1960s and 1970s, the United States used six manned moon landings in the Apollo program and retrieved a total of 381 kilograms of lunar soil and lunar rock samples from the moon.
In the 1970s, the former Soviet Union used three unmanned probes on Lunar 16, Lunar 20 and Lunar 24 to retrieve a total of 330 grams of lunar soil samples.
Counting from the last lunar sample return of the Soviet Lunar 20 probe in 1976, humans have not obtained lunar samples for 44 years.
The Chang’e-5 probe consists of four parts: the orbiter, the lander, the ascender, and the returner.
The orbiter refers to the lunar orbiter. After Chang’e 5 enters the lunar orbit, the orbiter first resides in the orbit, waiting for the subsequent use of the returner to return to the earth.
The lander is equipped with a reverse thrust rocket to perform a soft landing on the lunar surface, and automatically conduct lunar surface sampling and sample packaging operations.
The ascender uses the lander as a launcher, takes off from the lunar surface, carries the lunar soil samples into the lunar orbit, and transfers the lunar soil to the returner.
The return device is the part of the structure that finally carries the lunar soil sample back to the earth, and withstands the high temperature and impact when it enters the earth’s atmosphere at high speed, protecting the sample from being affected.