This article is from WeChat official account: intellectual things (ID: zhidxcom) , Author: letter instrument, editor: desert shadow, the original title: “A Historic Day in China’s Aerospace! The successful launch of Chang’e 5, 44 years later, mankind will go to the moon to “dig earth””, the title picture comes from: Visual China

November 24 news from Zhidongzhi, just now, at 4:30:21:806 Beijing time, my country’s “Long March 5” rocket carrying the “Chang’e 5” lunar probe was successfully launched at the Wenchang Space Launch Site in my country. Kong, this is the first step for “Chang’e 5” to return to the mission from the moon for the first time!

3! 2! 1! ignition! An exciting moment!

Long March 5 launches into the sky Source: CCTV News Live

This time “Chang’e” is more than just going around the moon, exploring the path and taking some photos back. This time, what she has to do is to “dig earth” on the moon and take the soil on the moon Brought back to China with Rock and Rock can be called the unmanned version of “Apollo Moon Landing.”

The United States and the Soviet Union brought back soil samples from the Moon through manned spacecraft and lunar probes in the 1960s and 1970s, but from the Soviet Union’s Lunar 24 probe on August 18, 1976 Since the last lunar sample collection, humans have not updated the lunar soil samples for 44 years, and today China is finally collecting lunar soil!

Lunar soil samples brought back from Apollo 15

Ouyang Ziyuan, the chief scientist of China’s lunar exploration project and an academician of the Chinese Academy of Sciences, who is known as the “Father of Chang’e”, said that “Chang’e 5” will achieve four major first breakthroughs in my country:

  1. Automatic sampling on the surface of the moon for the first time;

  2. First take off from the moon;

  3. The first unmanned rendezvous and docking on the lunar orbit 380,000 kilometers away;

  4. For the first time, the lunar soil was brought close to the second cosmic speed (If air resistance is not included, its value is 11.2km/s, which is the first √2 times the speed of the universe) return to Earth.

China’s lunar exploration program, the Chang’e project, was officially launched in 2004. The Chang’e project is divided into three stages: “unmanned lunar exploration, manned landing on the moon, and establishment of a lunar base”. At present, our country is still in the stage of “unmanned lunar exploration”, which is divided into three steps of “orbiting, falling, and returning”.

Currently, the missions from “Chang’e-1” to “Chang’e-4” have successfully completed the first two steps of “circumnavigation and landing”. If the mission of “Chang’e-5” is successful, the third step of the lunar exploration project will be realized. Strategic objectives.

It is said that the mission to be completed by “Chang’e-5” is known as one of the most complicated space missions in my country so far. What is the complexity of this mission? What tasks have the previous “Chang’e” probes accomplished? If this “digging” task is completed, what meaning will it have for our country and the human beings on earth? Today, let us follow the article to explore.

Ten years of grinding a “tool”

Since 6 o’clock last night, Zhizi has been watching the launch of “Chang’e-5” in front of the screen.exhibition. As the lights around the tower are getting brighter, we know that this means that the time to launch is getting closer…

Tonight’s moon looks slightly red to the naked eye. I don’t know if the moon rabbit has red eyes and is welcoming the arrival of “Chang’e 5.”

At 4:30, the rocket ignited and launched, and the dazzling red light illuminated the night! We can see the plume from the rocket engine.

Long March 5 launches into the sky Source: CCTV News Live

As the flame gradually changed from red to golden yellow and then to blueish visually, the booster separated at 4:33.

Booster separation Source: CCTV News is live

At 4:36, the fairing separated, and Chang’e-5 revealed its true face.

Cut separation source: CCTV News is live

At 4:39, the first and second rockets separated.

At 4:43, the Rockets shut down at the second stage.

At 5:05, the Rockets shut down for the second time.

At 5:06, the main engine shut down.

At 5:07, the posture adjustment is over and the devices are separated, which means that Chang’e-5 has begun to work autonomously in space.

The posture adjustment is over, the device is separated Source: CCTV News is live

The burst of this moment, and the half-hour holding your breath, are behind the hard work of countless people day and night.

On November 17, 2020, one week before launch, the Long March 5 Yaowu carrier rocket and the “Chang’e-5” probe completed the technical zone assembly test at the Wenchang Space Launch Site in China and were vertically transferred to the launch zone. 101 launch station, prepare for launch, and wait for the window period to appear.

Long March No. 5 RemoteFive carrier rockets are transported vertically to the launch area. Source: Xinhua News Agency

For the question of why we choose to launch in the early morning, Qian Hang, a PhD from the General Design Department of the First Academy of China Aerospace Science and Technology Corporation, said: First of all, launching in the early morning is most conducive to the design of the rocket’s orbit to the moon; the second is to reduce solar activity. The impact of “Chang’e 5”; third, there are fewer clouds in the sky at night, which is conducive to signal propagation; fourth, the overall environmental brightness is low in the early morning, which is convenient for observation.

The “Long March 5” rocket is already an old friend of China’s aerospace. From December last year to this year, our “Fat 5”-“Long March 5” series of carrier rockets were completed within one year The four-engine flight mission is unprecedented.

The total length of “Fat Five” is 56.97 meters, the take-off weight is 863 tons, and the diameter of the rocket is 5 meters. It will be bundled with 4 boosters. The “Chang’e Five” probe is seated in the fairing of “Fat Five” before launch. in.

The staff said that the “Long March V” relies on liquid hydrogen and liquid oxygen fuel, which can achieve non-toxic and pollution-free launch.

According to CCTV news, due to the constant changes in the positional relationship between the earth and the moon, the “Chang’e 5” mission has only three days, two days in November, one day in December, and 50 minutes a day.

Therefore, the “Long March V” launches the “Chang’e V” with the “narrow window and multi-orbit” scheme this time, that is, each trajectory covers a 10-minute window, and 5 trajectories can achieve a 50-minute window.

“Narrow window multi-orbit” is an important measure to improve launch probability and launch reliability. Even if there is an abnormality in a certain period before the launch, the emergency response will be delayed for a few minutes, and there can be a launch opportunity. The same technology was also used in the launch of “One”.

Let’s talk about the top priority of our mission-the “Chang’e-5” probe.

The “Chang’e-5” probe is the first in China developed by the Chinese Academy of Space Technology(The Fifth Academy of China Aerospace Science and Technology Group) The spacecraft that implements unmanned lunar surface sampling and return has a total weight of 8.2 tons and consists of four parts: an orbiter, a returner, a lander, and an ascender, and 15 subsystems.

“Chang’e No. 5” structure diagram Source: People’s Daily Client

Be aware that “Chang’e-1” and “Chang’e-2” only have one orbiter, and “Chang’e-3” and “Chang’e-4” also have only one lander and one patrol vehicle. Compared with this, the equipment of “Chang’e 5” can be regarded as the current “Chang’e world top equipment.”

From 2013 to the initial sample development stage, to the launch of the Pathfinder in 2014, my country’s layout and efforts for the “Chang’e 5” lunar exploration mission have been far more than ten years.

Disassembly of several key difficulties in the “Chang’e-5” mission

The “unmanned lunar exploration” phase of China’s lunar exploration project is divided into three steps: “orbiting, falling, and returning”. The current orbiting and landing missions have been successfully completed in the excellent performance of the previous months.

“Go around, fall, and return” in three steps

According to the plan for the third phase of the lunar exploration, the “Chang’e 5” will realize the mission of sampling the moon and returning to the earth, bringing back the first soil on the moon for our country. This mission is also called “the most complicated space mission in my country so far.”

Why is this task the most complicated?

Last year, Ouyang Ziyuan, an academician of the Chinese Academy of Sciences, introduced the “Chang’e 5″During the mission process and key nodes, he said: “We are going to launch the’Chang’e 5′, soft land on the moon, and then return with samples.”

“The core technologies of’Chang’e 5’currently achieving breakthroughs include: carrier launch, earth-moon transfer, near-moon braking, circumlunar flight, lunar descent, lunar surface sampling, lunar rise, rendezvous and docking, and circumlunar 12 parts of waiting, moon-earth transfer, orbit separation, re-entry and recycling.”

In addition, according to Peng Deyun, the overall chief designer of the “Long March 5” mission model team, the flight mission totaled 23 days, with 23 major orbital controls, 6 major separation controls, as well as power drop and monthly Face-to-face takeoff, rendezvous and docking and other related historical projects with relatively high risks. The team conducted several drills before the official launch of the rocket to ensure the smooth progress of the mission.

According to our collation, “Chang’e 5” must undergo at least the following difficult actions from launch to recovery:

Launch → Orbiter and lander solar wing deployment → Earth-moon transfer → Near-moon braking → Circumlunar flight → Orbiter and lander separation → Power down → Lunar drilling sampling → Lunar surface sampling → Ascent Take off on the moon surface → orbiter and ascender lunar orbital rendezvous and docking → transfer of lunar samples from ascender to returner → orbiter and ascender separation → enter the earth-moon transfer orbit → lunar-to-earth transfer → orbiter and returner separation → return Reentry into the atmosphere→Returner parachute opened→Returner landed and recovered

From the perspective of mission operations, a lunar exploration flight includes two launches (ground launch and lunar launch) and two landings< span class="text-remarks" label="Remark">(Lunar Landing and Earth Landing), sampling and twice encapsulation(Lunar Landing Encapsulation and Moon Track Encapsulation), one-time rendezvous and docking (month track docking).

1. Difficulties in launching

(1) Ground launch: The difficulty lies in the launch of the “Long March V”.

(2) Lunar surface launch: Compared to ground launch