The back of the moon has been working for three years! How did Chang'e 4 manage to extend its service life?

On January 15, the Chang'e-4 probe entered lunar night hibernation, and all systems were in good condition. On January 3, 2019, the Chang'e-4 probe landed in the Von Karman crater in the Aitken Basin on the far side of the moon, starting its lunar exploration journey.

As of today, the Chang'e-4 probe has been working on the far side of the moon for more than three years, and the Yutu-2 lunar rover has also traveled thousands of meters on the far side of the moon, which can be said to be over-serviced. So, what other tasks will be undertaken in the future?

The Chang'e-4 probe successfully landed on the Von Karman crater in the Aitken Basin on the far side of the moon on January 3, 2019, and carried out the first exploration of the far side of the moon in human history. It carried six effective scientific payloads, including a panoramic camera and an infrared imaging spectrometer, and conducted detailed exploration of the topography and soil composition of the far side of the moon, and has currently acquired more than 3,800G of scientific data.

Wen Weibin, deputy chief designer of the Chang'e-4 mission ground application system: According to our mission cycle, it has been working for 38 lunar days. We have analyzed various data and detection data and found that it is in very good condition. There are two payloads on the lander that are currently working for a long time. They should have the longest working time among all the payloads in our Chang'e-4 probe, and they also obtain the most data.

At present, the Yutu-2 lunar rover has traveled more than 1,000 meters, with an average of about 40 meters per lunar day. It is also the spacecraft that has worked the longest on the far side of the moon. In the future, Yutu-2 will continue to move northwest of the landing site.

Ren Xin, deputy chief designer of the Chang'e-4 mission's ground application system: Our general direction now is a basalt area to the northwest that is not covered by sputtering materials. It is about one kilometer away from us and it may take a long time to arrive.

Multiple designs to extend life

Achieve extended service

Before the Chang'e-4 probe was launched, the designers gave Yutu-2 a design life of three months. However, since it successfully landed on the back of the moon in 2019, the rabbit has been working for three years, far exceeding its design life. Why has it been able to maintain good working condition for such a long time?

The components and products used on my country's spacecraft are selected from the best, and their performance is set to the highest standards.

Fu Qiang, chief designer of the Chang'e-4 mission ground application system: At the beginning of the design, there was a very high reliability requirement for the selection of each component, with a guarantee of a long life and reliability.

Since the temperature on the lunar surface is between 160 degrees Celsius and minus 180 degrees Celsius, and the temperature difference between day and night is more than 300 degrees, the staff designed two rest modes for the spacecraft: lunch break and moon night hibernation, so that the Chang'e-4 probe can better adapt to the temperature of the moon.

Fu Qiang, chief designer of the Chang'e-4 mission's ground application system: After the test of 38 lunar days, the design of our work procedures is very reasonable.

In addition, since the moon has no protective layer, many space particles will affect the spacecraft on the lunar surface. In order to ensure that the work of Chang'e 4 and Yutu 2 lunar rovers is not affected, they have enhanced their radiation resistance at the beginning of their design. Thanks to these protections, not only can the service life of the spacecraft be extended, but the accuracy of the collected data is also guaranteed.

The Moon's Mystery Shack

What exactly is it?

Some time ago, a "mysterious cabin" was discovered on the moon, which became a hot topic on the Internet. So what exactly is this "mysterious cabin"?

This is a picture of the "mysterious house" on the moon, which was taken by the Yutu-2 lunar rover on the 36th lunar day. In the picture, you can see that there is an object shaped like a house at the horizon of the lunar surface.

Gao Xingye, chief designer of the Chang'e-4 mission ground application system: The reason why it looked like a small house before was because of the shooting distance and angle. The stone was located at the top of a slope, and our Chang'e-4 lunar rover was at the bottom of the slope, so it was looking up from the bottom, and we happened to see the stone on the horizon. From that angle, it looked like a rectangle and looked like a small house.

In fact, the "mysterious hut" is created in a similar way to how we see things with our eyes: things that are closer appear larger and farther away appear smaller. Under the influence of multiple factors such as light and background, visual illusions occur. On the 38th day of the month, the Yutu-2 lunar rover traveled to a distance of about 10 meters from the "little house" and took photos of the real appearance of the hut.

Gao Xingye, Chief Designer of the Ground Application System of the Chang'e-4 Mission: On the 38th day of the lunar day, we got closer and saw that this was not a small house, but actually a stone. We found that the stone was about 20 centimeters wide and 10 centimeters high, with a relatively large impact crater behind it, which was about 22 meters in diameter.

In fact, the image of the "mysterious hut" comes from part of the daily panoramic images of the Yutu-2 lunar rover. In order to ensure the safety of the Yutu-2 and the smooth progress of the exploration mission, it will take two 360-degree panoramic images during each lunar day to plan the route.

Over 1,000 images captured

Record the landforms along the way

As the only human spacecraft on the far side of the moon, the Yutu-2 lunar rover has taken more than 1,000 images during its three years of driving on the far side of the moon, recording in detail the topography and landforms along the way, providing valuable data for further research on the moon.

Since the moon has no protective layer, it is hit by meteors, forming impact craters of various sizes. During its journey, the Yutu-2 lunar rover also photographed impact crater landforms formed in different periods, which also provides more clues for us to further understand the moon.

Ren Xin, deputy chief designer of the Chang'e-4 mission ground application system: From the high-resolution photos taken by Yutu-2, we can see many typical landforms, such as some new impact craters, which can be tens of meters or even tens of centimeters in diameter. In addition, there are many large and small rocks.

The most obvious feature of the younger impact craters is that there are many rocks around them. In order to further understand the newer impact craters, the Yutu-2 lunar rover will spend a long time further exploring them.

Ren Xin, deputy chief designer of the Chang'e-4 mission ground application system: This pit was discovered on the eighth lunar day, and a very detailed exploration was conducted around it for nearly three months. The details are clearer, and the dark matter in the middle is much clearer than the previous picture. This stone was selected as the exploration object at the time, and it was photographed using a spectrometer, and its material composition was also analyzed in detail.

Now Yutu-2 has completed its 38th lunar day and is in lunar night hibernation mode. The rover will continue to move northwest of the landing site to obtain more effective detection data.

What are moon day and moon night?

Starting from the 15th, the Chang'e-4 probe ended its 38th lunar day work and began to enter lunar night hibernation. What are lunar day and lunar night?

In fact, the moon is similar to the earth. It rotates constantly, which forms the day and night on the moon, called lunar day and lunar night. But compared with the earth, the moon rotates much slower. One day on the moon is equivalent to 28 days on the earth. In other words, one lunar day is about equal to 14 days on the earth, and one lunar night is also equal to 14 days on the earth. Starting from today, the Chang'e-4 probe will be in lunar night dormancy for the next 14 days. After that, it will start its hard work of the 39th lunar day.

Source: CCTV News Client

Editor-in-charge: Wang Hongyu