“Jade Rabbit” moon back pioneer has survived more than 400 days driving mileage 405.44 meters

The legendary “Green Rabbit” – Jade Rabbit II lunar rover woke up again. On March 18, after 14 days of extreme cold moon night, Jade Rabbit 2 woke up again to “return to work” and ushered in the 16th month of the lunar tour. So far, Jade Rabbit 2 has survived more than 400 days on the back of the moon, with a cumulative range of 405.44 meters.

Jade Rabbit II photographed the back of the moon and its own shadow. Nasa Lunar exploration and space engineering center for mapping

“Jade Rabbit Swing Dance”

“Jade Rabbit Back”

“It’s been more than 400 days?” “There are netizens in the praise of the feeling of jade rabbit two vitality of the tenacious. In fact, as early as December 2019, jade rabbit 2 has been the world’s longest-running human probe on the moon since it ran for more than 340 days on the back of the moon. Previously, the record was set by the world’s first lunar rover, the Soviet Union’s lunar rover 1, and held for nearly half a century.

People who pay attention to the moon’s development often hear the news: “Jade Rabbit 2 wakes up again”, “The 4th enters a lunch break again”, and so on. So, in the back of the moon more than 400 days, the two high-profile Chinese probes, Chang’e-4 and Jade Rabbit 2, in addition to “walking” “sleep” “lunch vacation” what else?

“Move the rabbit”: or back or swing dance

On January 3, 2020, the National Space Administration’s Lunar Exploration and Space Engineering Center released a photo called “Jade Rabbit Swing Dance”, which attracted attention. From the photo, Jade Rabbit II in the original “drawing a circle”, the selected location of the moon surface for 360 degrees of “stepping point.”

More precisely, this is Jade Rabbit II in place steering detection: first travel to the predetermined detection area, and then in turn in eight yaw angle rotation, in different directions, infrared spectrometer, neutral atomic detector and other equipment “on-line” – boot detection, obstacle camera imaging, after detection, the detection data back to earth.

In addition, Jade Rabbit II also has its own “Jade Rabbit Back” – rut detection. The “Jade Rabbit Pilot” of Beijing Space Flight Control Center calculates the improved angle in advance to ensure that the infrared field of view covers the ruts of Jade Rabbit II. According to the instructions sent from the ground, the “head” of Jade Rabbit II turns to about 180 degrees, using an infrared spectrometer to “look back” to detect the moon soil that the rut sipped out.

Jade Rabbit II is also a focused “rabbit” – fixed-point detection. This is jade rabbit II in the “stand-up” state, to study the solar height angle changes on the moon surface of a point of the reflection spectrum.

According to the National Space Administration Lunar Exploration and Space Engineering Center researchers, when the Jade Rabbit 2 to the intended location, turn to the selected course, and then every two hours for infrared detection, timely infrared calibration and neutral atomic detection, before the arrival of the moon night to end the fixed-point detection work, and look for sleep points.

Whether it is “Jade Rabbit Swing Dance”, or “Jade Rabbit Back”, if you sum up in a word, in the past year or so, the lander carried out fixed-point detection “quiet place”, jade rabbit 2 lunar rover to carry out patrol exploration, is “move dislocated rabbit”. A static move, in the distant back of the moon staged a “hard-working pioneer” landscape.

The data and pictures obtained by these pioneering sands, analyzed and processed by ground scientists, have been transformed into scientific achievements and expanded the boundaries of human understanding of the moon.

According to the National Space Administration’s Lunar Exploration and Space Engineering Center, the outbreak of new crown pneumonia hit in 2020, but that did not cause Jade Rabbit II and the research team behind it to press the “pause button”: on the first anniversary of the landing on the moon on January 3, 2020, the center released more than 210GB of scientific data at all levels. Based on this data, a team of Chinese and foreign scientists has made a series of important scientific discoveries.

On February 27th, a team led by Li Chunlai, a researcher at the National Observatory of the Chinese Academy of Sciences, obtained in-place detection data using the lunar radar mounted on Jade Rabbit II, and found that the underground material on the back of the moon consists of low-loss lunar soil material and a large number of rocks of different sizes. This is the first time that man has demystifyed the underground structure on the back of the moon.

Li Chun said that from this achievement can be seen “something that man has never seen before”: from the surface of the moon to the ground 12 meters, the formation is a fine moon soil, embedded with a small number of stones, is from multiple impact craters stacked with sputterers weathered; It is mixed in fine grain moon soil, and from 24 meters to 40 meters underground, it is a different period, the older sputtering sedimentation and weathering products, which greatly expand the human cognitive range.

Above the moon, the wise “twisted” and the hard-working “rabbit” are trying to go further and work longer hours to provide more scientific data for mankind.

A Day on the Moon: Half the Time Is “Sleeping”

In the news about Jade Rabbit II, people often hear the words “sleep” and “wake up”, literally as if it is the biological instinct of life, and Jade Rabbit II is a sophisticated lunar probe, how can such operations be needed?

It also starts with the objective environment of the moon. The moon’s day is equivalent to about 27 days on Earth, half of which are day, called the moon day, and the other half is night, the so-called moon night. During the moon’s night, the moon surface temperature will drop to around minus 190 degrees Celsius, and working at too low temperatures will cause damage to the lunar rover and its scientific equipment.

Therefore, before the arrival of the night of the moon, Jade Rabbit 2 will follow the predetermined strategy to travel to the sleep point, the head turned south, fixed side solar sails facing east. With the sun’s altitude angle drops, the temperature gradually lowers, the Earth’s “Jade Rabbit Driver” will control the Jade Rabbit 2 open heating device, access to “heating.”

When the night of the month comes, Jade Rabbit 2 began to sleep settings, close the mast and one side of the solar sails, the use of nuclear sources for insulation, the use of a safe posture into the “dreamland.”

Fourteen days later, the sun rises, the day of the moon comes, and the new moon begins.

When the sun shines on Jade Rabbit II, fixed side solar sails to reach a certain power generation power, will automatically wake up to start – power on, the center computer boot, the active side of the sun wing and mast in turn, and actively to the “Bridge” relay star sent a communication signal, told the earth’s “Jade Rabbit Driver”: “I got up!” “

After receiving the signal, the ground “Jade Rabbit Driver” will send the latest instructions to Jade Rabbit 2, parameter settings, Jade Rabbit 2 into the working state of the moon.

Of course, even in the “day” of the moon, this rabbit is not a “workaholic” who has plunged into scientific exploration. The day of the month “noon” approached, the moon surface temperature reached the highest, jade rabbit 2 will turn the head to the west. Accordingly, the ground “Jade Rabbit Driver” set Jade Rabbit 2 into the minimum operating mode, so that it better into the moon “summer vacation.”

With the sun’s altitude angle drops, the temperature gradually drops to the suitable working temperature, the ground “Jade Rabbit Driver” set jade rabbit 2 exit the minimum mode of work, the beginning of the day “afternoon” work.

For you to live longer, enough “sleep” and enough “rest” are necessary. In this sense, “moon night rest” “moon day and day break” these are also part of the work of Jade Rabbit II.

“Longevity Rabbit”: Detection Results Are More Important

According to data previously released by the National Space Agency, jade rabbit 2 has a design life of three months. Today, Jade Rabbit II’s survival time has already exceeded this figure, even surpassing the Soviet Union’s “predecessors” to become the longest-working “long-lived rabbit.”

However, in the view of Liu Tianfu, director of the mobile sub-system of The Eight-Yuan Jade Rabbit II of China Aerospace Science and Technology Group, whether it is the length of the life of Jade Rabbit II or the distance of its walking distance, is not the most important indicator at present. In his view, the more important question is whether Jade Rabbit II can detect more scientific results.

He said that three months is only a “life-span bottom line” designed by researchers, in order to meet the bottom line requirements, the team of course hope that Jade Rabbit II can work for a year or more. In fact, China’s first lunar rover Jade Rabbit design life is only 3 months, but eventually worked on the moon for 972 days.

According to Liu, the so-called “design life” is based on engineering objectives: on January 3, 2019, the Chang’e-4 probe successfully landed in the von Carmen impact crater in the Antarctic-Aitken Basin on the back of the moon; The two instruments completed the mutual imaging, the Chinese and foreign scientific load work normally, to achieve the project’s stated goal, marking the success of the mission.

“The completion of these engineering objectives has achieved the intended plan, and the researchers have designed the life span of Jade Rabbit II according to these objectives. Liu said the next probe, to some extent, was a task other than “prescriptive action.”

Six years ago, Jade Rabbit II’s “sister” Jade Rabbit, after walking 114.8 meters on the moon’s Hongwan, suddenly appeared a short circuit in the cable, and has never been able to walk again. This is china’s space science and technology group eight courtyard no. 4 deputy commander and deputy chief designer Zhang Yuhua in that mission the most memorable thing, “I was thinking, if I can send to the moon, wrap it, maybe ‘Jade Rabbit’ would be good!” “

Since then, Zhang Yuhua has led the team in optimizing the design, evaluating and verifying it over and over again, and they have spent five years ensuring that the follow-up tasks are foolproof. She said: “When I saw the ‘Jade Rabbit’ standing on the deserted moon, I thought it was like a silver swan, more beautiful than anything else. Now our Jade Rabbit 2 goes to the back of the moon, we hope it is beautiful and brave, keep going. “

Shen Zhenrong, the overall director of the China Aerospace Science and Technology Group’s five-yard-and-4-inspector,said that Jade Rabbit II is more “robust” than Jade Rabbit and has a stronger ability to cope with difficulties, “if you liken it to a child, although the appearance doesn’t seem to change much, but it’s more mature and stronger.” “From this point of view, the future performance of Jade Rabbit II is also more worthy of expectation.

In the previous month, at the request of the team of scientists, jade rabbit 2 to the south side of the route of the impact crater approaching, because the surrounding terrain is too complex, this “rabbit” had to “look at the pit sigh”. But in the end, it detected the sputtering rubble in front of the crater and took panoramic pictures of the impact crater.

Subsequently, the jade rabbit two a turn, resolutely bid farewell to the south side of the deep pit, continue to explore the journey. Waiting for it will be the next moon day.

The area covered by basalt on the back of the moon (inside the red line) and the white cross is where Jade Rabbit II is located.

Large deep pit photo on the back of the moon. Beijing Space Flight Control Center For Map

Up to now, Jade Rabbit 2 has survived more than 400 days on the back of the moon, with a cumulative range of 405.44 meters. Counting down, this “rabbit” on average a day to walk about a meter, walk ingress on the moon, is it so difficult?

The farthest distance from earth is at the farest distance of the moon. Operating a lunar rover in such a distance is not as easy as driving on the ground. Simply put, the “Jade Rabbit Pilot” of the Beijing Space Flight Control Center generally needs to give it five remote instructions to sense, plan, execute, hibernate, and wake up to the rabbit.

The perception is that the moon is photographed using a navigation camera. According to the photos taken by the navigation camera, the “Jade Rabbit Driver” on the ground can restore a digital image of the lunar surface to determine the specific situal surface, including the width and narrowness of the impact crater, the depth of the rock, the distance and so on.

After sensing the surrounding environment of Jade Rabbit II, ground controllers will plan a path that Jade Rabbit II can travel safely and set various navigation points from the starting point to the end, based on the digital image map on the back of the moon and the detection target pointdetermined by the team of scientists, according to the lunar rover’s ability to cross the barrier and climb.

This process is similar to human driving on the ground: after determining the destination, a optimal route of arrival is planned based on the map and its surroundings.

Once the route has been determined, it’s just beginning.

Beijing Space Flight Control Center’s “Jade Rabbit Driver” – remote operation team, to convert the planning results into control instructions, through the ground deep space station sent to the “Bridge” relay star, relay star and then forward the instructions to the back of the moon, the jade rabbit 2 lunar rover, the latter will be in accordance with the instructions to complete the mobile work.

However, before issuing each instruction, these “jade rabbit drivers” must see the distant moon situation, plan ahead for the long term – in the jade rabbit forward, they have been worried that in the moon “visible” under the impact crater, hidden a lot of years of huge degradation impact crater.

According to a “Jade Rabbit Driver”, during the 15th month of work on Jade Rabbit II, ground staff encountered the challenge of a “strategic shift”

From the photo sent back by Jade Rabbit 2 and the moon surface high-definition image comparison, the then Jade Rabbit 2 is located in the middle of two diameter s16 meters and 9 meters in diameter, most members of the control team suggested that bypassing the 16-meter impact crater all the way west, because this direction looks like a horse Pingchuan, some people have even begun to plan a follow-up path.

Jade Rabbit 2 Deputy Chief Designer in the day but belatedly willing to clap board. He frowned, stared at the image, suddenly greeting everyone around, pointing to the current point of the image on the west side of the position said: “You see, the left side of this area looks dark, the right side is bright, what is this?” This is a typical impact crater feature. “

According to him, the impact crater is different from the previous encounter with Jade Rabbit II, which is likely to be a degenerative impact crater that has existed for hundreds of millions of years. At his request, the ground navigator Wang Wei superimposed the contours on the situation map, and soon, on the path previously proposed by most people, a large hidden pit was outlined.

“That’s it!” An oversized impact crater, due to its age, the pit edge has become illegible, the interior has been hit by large and small meteorites, can be described as dangerous ring life. On the northeast side of the crater, there are also small impact craters arranged in a tight and dense manner, Yu said. Once jade rabbit 2 went there, it will fall into the blockade of multiple impact craters, the group pits surrounded, it is likely to go in and out.

The ground team quickly agreed that the driving strategy would be changed from “Southern March” to “Northern War” to carry out “strategic shift”.

They decided to let the jade rabbit move north, first bypassing the small impact crater on the northwest side, and for the next few months, continuing northwards until it bypassed the super-large impact crater and then rerouted to the west.

Few people know, jade rabbit two every step, need the ground “Jade Rabbit driver” how much effort.

According to convention, the morning of the moon, jade rabbit 2 to walk in the northwest direction, but on the lunar surface image map, the ground “Jade Rabbit Driver” found a impact crater on the northwest side: the pit looks like a black hole, as if the collapse of the cliff, people are daunting.

The impact crater can be seen vaguely by the original image of the panoramic camera. But the map in this direction was so bright that it could not be seen, and they decided to let the jade rabbit move forward first, approach and then retake the picture to confirm the terrain.

After the move, the Jade Rabbit Driver quickly got a re-sensory image of the navigation camera. However, at this time the sun is lower in height and is located on the back of the jade rabbit imaging direction. The northwest side of the new image is still occupied by direct light and the shadow of the jade rabbit itself, and the “Jade Rabbit Driver” is still unable to see the area.

“If you can’t see the full extent of the pit, you can’t see its boundaries. “One ground crew said that, after considering it, they decided to take another panoramic view of the area when the next day was right. The next day, get clear pictures that make them feel “shocking”

A large impact crater about 20 metres in diameter lay quietly, surrounded by small, pothole-infested craters and sputtering stones. Fortunately, did not let the jade rabbit 2 continue to go northwest, otherwise once slipped into the pit, the consequences can not be imagined.

In this way, Jade Rabbit II embarked on a “tour around the pit.” Subsequently, the rabbit will also bypass the west ridge and travel westward, with the ultimate goal of “basalt” about 1.8 kilometers from the landing site.

There, Jade Rabbit II will explore more mysteries about the back of the moon. Of course, this road down, is still pit stony all over, ditches, may have to move over the years, but the journey of scientific exploration has always been tortuous and long, has already set sail, it will not fear hardship.