Yutu II[80]）, developed in ChinaChang'e-4Mission rover (rover).
The Yutu 2 lunar rover has a design mass of 135 kg, and its energy is solar energy. It can withstand the extreme environment of vacuum on the moon surface, strong radiation, and the extreme temperature from minus 180 ℃ to minus 150 ℃.The lunar rover has the ability of 20 degree climbing and 20 cm obstacle surmounting, and is equipped with panoramic camera, infrared imaging spectrometer, lunar radar, neutral atom detector and other scientific exploration instruments[65]。
At 22:22 on January 3, 2019, the Yutu 2 lunar rover separated from the Chang'e 4 lander and arrivedBack of the Moon。The first landing on the back of the moonChina's space industryAnother milestone of development.[1]
(The overview picture shows the topography camera of Chang'e-4 lander imaging the Yutu II rover[3]）
Lunar rover, full name of "lunar surface patrol detector", is a special vehicle that can travel on the lunar surface and complete complex tasks such as lunar exploration, investigation, collection and analysis of samples.
The world's first unmanned lunar rover
On November 17, 1970, the world's first unmanned lunar rover was sent to the moon by the lunar rover 1 carried by the former Soviet Union's Lunar 17.After landing in the "Rainy Sea" area on the lunar surface, the probe traveled 10.5 kilometers, carried out 10 and a half months of scientific exploration, investigated the 80000 square meters of the lunar surface, until the energy carried was exhausted, and stopped working on October 4, 1971[69]。
The world's first manned lunar rover
On July 31, 1971, the day after the American Apollo 15 landed in the "Rainy Sea" area of the moon, astronauts Scott and Owen carried out the first manned lunar rover drive in the history of space.Two astronauts drove a four wheel lunar rover and traveled 27.9 kilometers on the rough surface of the moon, collected 77 kg of lunar rock samples, and then returned to the lunar module[69]。
Schematic Diagram of Chang'e-4 Flight Orbit
Development history
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Project establishment and development
1991
Chinese aerospace experts propose to carry out the lunar exploration project[70]。
1998
The Commission of Science, Technology and Industry for National Defense of China formally began to plan and demonstrate the lunar exploration project, and carried out early scientific and technological research[71]。
2004
On January 23, Wen Jiabao, then Premier of the State Council of China, approved the establishment of the lunar exploration project.
On February 25, the first meeting of the leading group of the lunar exploration project was held. The meeting adopted the General Requirements for the Development of the Lunar Exploration Project, and named the project "Chang'e Project".
On March 15, the Commission of Science, Technology and Industry for National Defense appointed the chief commander and chief designer of the five major systems.
On November 19, the leading group of the lunar exploration project held the second meeting to review and pass the project into the prototype development stage[72]。
Subsequently, Chinese research and development units began to carry out research and development work, including the Chang'e-4 probe and rover.As China's major national science and technology project, the lunar exploration project is the third milestone in the development of space science and technology after China's development of artificial satellites and manned spaceflight[73]。
Naming determination
2018
On August 15, during the name seeking activity of Chang'e-4 mission lunar roverXinhua News Agency client42945 names were received by www.china.com.cn, Tencent and mail letters.A 23 member review committee composed of experts in aerospace science and technology, university language and culture celebrities, and the chief editor of the national mainstream media conducted a letter review and screening, and recommended 153 names for preliminary review.
On September 28, a preliminary review was organized, and "Dream Chasing, Bright, Jade Rabbit No. 2, Exploration, Journey, Spirit, FearlessWangshu, travelerGolden rabbit”The 10 finalists will be voted online by the masses.
From September 20 to October 10,Xinhua News Agency client、Chinanet、Tencent, a total of 448206 votes were received, of which 314860 valid votes were received by China.com, and 133346 valid votes were received by the Xinhua News Agency client sharing the voting link with Tencent[9-10]。
2019
On January 3, the Chang'e-4 mission lunar rover was finally named "Yutu 2"[9-10]。
Naming meaning
Chang'e-4The name of the mission lunar rover reflects the cultural origin of the Chinese lunar exploration project named Chang'e ProjectChang'e-3“Yutu”Chang'e-4 relay satellite“Queqiao”It comes down in one continuous line, which is not only easy to be accepted by the masses, but also easy to remember and spread.At the same time,Jade HareThe image of kindness, purity and agility is similar to the structure and mission of the lunar rover, which reflects China's position on the peaceful use of space[9-10]。
Chang'e-4
system composition
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Chang'e-4
As the first mission of the fourth phase of the lunar exploration project, Chang'e-4 has achieved the first soft landing and patrol survey on the back of the moon, and also achieved the first measurement and control, data transmission and relay from the L2 point relay satellite to the earth to the moon.The scientific objectives of the Chang'e-4 mission include: lunar based low-frequency radio astronomy observation and research;Exploration and research on the topography and mineral composition of the patrol area on the back of the moon;Exploration and Research on the Shallow Structure of the Patrol Area on the Back of the Moon[73]。
overall design
Lighter
The Yutu 2 lunar rover weighs less than the Yutu, the Chang'e 3 lunar rover weighs 137 kg, and the new lunar rover weighs 135 kg, making it the lightest lunar rover in history as of January 2019.The main reason for the lightening is that the mechanical arm with the particle excitation X-ray spectrometer was removed and the neutral atom detector developed by Swedish scientists was replaced to detect the particle radiation environment on the moon surface.Yutu II inherited the panoramic camera, lunar radar and infrared imaging spectrometer of Yutu II.
More autonomy
Since Chang'e-4 landed on the back of the moon, although it has a relay satellite, its communication is not as convenient as Chang'e-3, so the Yutu 2 lunar rover can enter a sleep state independently according to the lighting conditions, and can also enter a stable working state independently after waking up.
Stronger
The layout of various routes on the Yutu II lunar rover has been improved, and protective measures have been taken to avoid short circuit.In addition, fault isolation design shall be done well in the system.When a local problem occurs, the problem will not be further expanded.The Yutu II lunar rover has a stronger structure and is more capable of coping with harsh environments and difficulties[74]。
Special design
Different from all previous lunar rovers, Yutu II is the first time to patrol and explore the back of the moon.In view of the complex terrain conditions faced by the mission, the new requirements for relay communication, the actual needs of scientific objectives and other factors, Yutu 2 has special designs in terms of movement safety, energy supply, scientific detection, measurement and control communication, etc[75]。
Schematic diagram of the combination structure of Chang'e-4 landing area patrol
Design parameters
Reference data of Yutu II lunar rover
Basic parameters
long
1.5m
wide
1m
high
1.1m
Total mass
135 kg[65]
performance parameter
Climbing
20 degrees
Surmount obstacles
20cm
Tolerable temperature difference
330 ℃[65]
Maximum moving speed
200 m/h
Design life
3 months[65]
Mission load
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Yutu No. 2
Yutu II lunar roverPanoramic camera, lunar radar, infrared imaging spectrometer andNeutral atom detector。These instruments will carry out low-frequency radio astronomy observation and research on the back of the moon through positioning and patrol detection, study the topography, mineral composition and shallow structure of the moon surface in the patrol area, and carry out experimental neutron radiation doseNeutral atomAnd so on.In addition, the lander is also equipped with a lunar surface biological science popularization test load[11]。
Panoramic camera
The Jade Rabbit is equipped with two panoramic cameras, which are installed on the PTZ of the mast of the Jade Rabbit to achieve panoramic imaging of the patrol area and landing area through the rotation and elevation of the PTZ.Each camera is composed of optical lens, electronics, and chassis;The band range is visible light, the imaging mode is alternating between color imaging and panchromatic imaging, and the normal imaging distance is equal to or greater than 3 meters. It is used for optical imaging of the lunar surface in the landing area and patrol area, research on the lunar surface topography in the patrol area, investigation and research on the impact crater in the patrol area, analysis and comprehensive research on the lunar geological structure in the patrol area[66]。
Lunar radar
The first ultra wideband lunar radar in the world, installed at the bottom of the Yutu II lunar rover, can be used to directly detect the lunar soil structure within 30 meters on the patrol route and measure the shallow lunar shell structure 100-200 meters below the lunar surface, which has never been done before.
The lunar radar has two detection channels, and one is used to detect whether the structure of the lunar soil layer is divided into several layers at a depth of 30 meters, how to divide them, and whether there are big stones;The other is to explore the upper structure of the moon at a depth of 100-200m.The radar measures while walking with the lunar rover, which is equivalent to cutting the ground while walking to see what layers the lunar soil has, and whether there are large stones or other structures in the soil[66]。
infrared imaging equipment
Yutu 2 separation procedure
The infrared imaging spectrometer carried by the Yutu II lunar rover includes two spectral bands, namely, visible near-infrared and short wave infrared. It can obtain high-resolution reflection spectra and images from visible near-infrared to short wave infrared, which can be used for infrared spectral analysis and imaging detection of the lunar surface in the patrol area, complete the analysis of the composition and distribution of minerals on the lunar surface in the patrol area, and comprehensively study the energy and mineral resources in the patrol area.
The infrared spectrum can be used to observe the spectrum very carefully and judge different substances.During the lunar rover's journey, this spectrometer can image along the direction of travel and detect the composition of the lunar surface material[66]。
Neutral atom detector
Installed on Yutu II lunar roverNeutral atom detector(Advanced Small Analyzer for Neutrals, ASAN), the neutral atom detector is a detector jointly developed by China and Sweden, which can detect how the solar wind acts on the moon surface by detecting neutral atoms and ions on the moon surface[65][67][73]。
Detection history
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Launch landing
Launch
2018
At 2:23 on December 8, the Chang'e-4 mission lander and rover (lunar rover) combination was built by ChinaLong March No.3 BLaunch of carrier rocket, starting a new journey of lunar exploration[77]。
Lunar landing
Chang'e-4 lunar landing area
2019
At 10:26 on January 3, the Chang'e-4 lander successfully landed on the back of the moon and sent back the world's first close-up image of the moon back through the "Queqiao" relay star[9]。China's "Chang'e-4" probe successfully achieved the first soft landing on the back of the moon and released the lunar rover "Yutu II", which is the seventh vehicle on the moon as of January 2019[6]。
At 15:07 on January 3, scientific and technical personnelBeijing Space Flight Control CenterThe command was sent to the Chang'e-4 probe through the "Queqiao" relay satellite, and the separation of the two devices began.On the screen of the flight control hall of the Beijing Space Flight Control Center, the Chang'e-4 lander stands on the moon and the solar wing is unfolded.The inspector stands on the top of the lander, extends the solar wing and extends the mast.Then, the inspector starts to move slowly towards the transfer mechanism.The transfer mechanism is unlocked normally, and an inclined ladder is set up between the lander and the moon surface, and the inspector slowly moves towards the moon surface along the inclined ladder.
At 22:22 on January 3, the Yutu II rover stepped on the surface of the moon[12]。
Start up
Successful startup
At 17:00 on January 4, Chang'e-4 lander went to low frequencyRadio spectrometerThree 5m antennas of,GermanyThe lunar surface neutron and radiation dose detector was powered on for testing, and the images taken by the terrain camera were sent back to the ground in succession.The Yutu II rover successfully established an independent data transmission link with the repeater, completed environmental awareness and path planning, walked on the lunar surface as planned to reach point A, and carried out scientific exploration.The lunar radar and panoramic camera have been turned on and working normally.Other payloads will start in succession[1]。
Take an opportunity lunch break
In order to reduce the heat generated by its own work, the Yutu II lunar rover entered the "lunch break" mode when selecting the machine, leaving only part of the subsystems working, while the mobile subsystem stopped working, and is expected to wake up on January 10.The lander has strong thermal control capability and can still work at noon on the moon. The terrain camera and other payloads will continue to carry out corresponding scientific exploration.
On January 10, the Yutu II mission ended its "lunch break" and was successfully awakened to continue its inspection and exploration of the back of the moon[13-14]。
Moonlight Sleep
On February 11, the Yutu II rover entered the lunar night sleep mode again. After the moon set, it traveled on the moon for a total of 120 meters.Yutu 2 is expected to wake up on February 28 to continue scientific exploration activities[17-18]。
Take photos
Two devices shoot each other
On January 11, the Chang'e-4 lander and the Yutu 2 rover worked normally, and the mutual shooting was successfully completed with the support of the "Queqiao" relay star. The ground receiving images were clear and intact, the Chinese and foreign scientific payloads worked normally, the detection data was effectively downloaded, and the carrying scientific experiment project was successfully carried out, reaching the set goal of the project, marking the complete success of the Chang'e-4 mission.So far, China's lunar exploration project has achieved "five victories in five wars"[15]。
Mooncake photo
On September 13, 2019, the trajectory of the moon cart was "like" the moon cake
On September 13, the picture of "Yutu II" drawing moon cakes on the moon surface was released.It can be seen from the photo that the driving track of the lunar rover has formed a perfect circle, which is similar to the shape of a moon cake[16]。
Follow up detection
2019
On March 13, the "Yutu II" lunar rover completed three months of daytime work, and entered the third lunar night at 12:16, traveling 163 meters in total.The lander was set at 12:00 on the lunar night.[45]
At 20:28 on March 29, the Yutu II lunar rover woke up independently, the forward return link of the relay was established normally, and the platform was in normal working condition.The Yutu II lunar rover will carry out the daytime work in April as planned, and continue to carry out the patrol scientific exploration mission.Scientific researchers will operate precisely and monitor closely to ensure more fruitful scientific achievements.[19]
At 7:40 on April 29, the Chang'e-4 lander woke up normally, the forward return link of the relay was established normally, and the working condition of the platform was normal.Later, the Chang'e-4 lander will cooperate with the Yutu 2 lunar rover to carry out the work in the fifth day and continue the scientific exploration mission.[46]
At 23:40 on June 9, the Yutu 2 lunar rover successfully completed the day work in the sixth month according to the scientific exploration needs, completed the moon night setting, and entered the dormant period of the sixth month night.[20]
At 9:10 on July 9, the Yutu 2 lunar rover completed its work in the day of the seventh month, ushered in the moonlight, and entered the "dreamland".In the seventh day of July, the Yutu II lunar rover continued to move along the established route, and carried out relevant exploration work at multiple detection points,Infrared spectrometer, panoramic camera, neutral atom detector and lunar radar have obtained a large amount of scientific exploration data.[21]
On the evening of August 7, the Yutu 2 lunar rover and Chang'e 4 lander had successfully completed their eighth day work and entered a new round of lunar night sleep.Before going to sleep, the "Yutu II" had driven 271 meters on the back of the moon, breaking the record of Chinese lunar rovers on the moon.[22]
At 20:30 on September 22, the Yutu 2 lunar rover safely passed through the extremely low temperature environment on the moon night for 14 days, successfully "wakened up" by the light, and entered the working period of the tenth month.The Yutu 2 lunar rover traveled 284.661 meters in total.[23]
At 15:43 on October 5, the Yutu 2 lunar rover completed its lunar night setup and went into sleep.During the October day, the inspector moved according to the overall plan, and walked 289.769 meters in total.During the movement of the rover, the startup detection of the rover's infrared spectrometer, panoramic camera, neutral atom detector, lunar radar and other payloads was organized and implemented as planned to further obtain the scientific research data on the back of the moon, and the data transmission of the ground receiving load was normal.[24]
Wake up on October 22, 2019
At 11:45 on October 22, he successfully woke up spontaneously.During the daytime working period of this month, the Yutu 2 lunar rover will carry out fixed-point exploration according to the planned route, and continue to carry out scientific exploration tasks including lunar surface morphology, material composition and shallow surface structure exploration.The Yutu 2 lunar rover has walked 289.769 meters in ten months' working days.[25]
In the early morning of November 4, the Yutu 2 lunar rover successfully entered the eleventh lunar night dormancy period after completing the scheduled work in the day of November.During the day of November, the Yutu II lunar rover carried out inspection and exploration at several detection points. As of November 4, the rover had traveled 218.11 meters northwest of the lander, and the accumulated mileage had successfully exceeded 300 meters, reaching 318.621 meters, again breaking the walking record of Chinese probes.[26]
At 21:42 on December 3, after completing the work of the twelfth lunar day, the Yutu 2 lunar rover completed the lunar night setting according to the ground instructions and entered the lunar night sleep mode.During the day of December, the Yutu II lunar rover continued to move along the planned route, and carried out relevant detection work at multiple detection points. The infrared spectrometer, panoramic camera, neutral atom detector and lunar radar were started up as planned to continue to obtain scientific exploration data.The lunar neutron and radiation dose detector and low-frequency radio spectrometer on Chang'e-4 lander worked normally.Since January 2019, the Yutu II lunar rover has successfully landed on the back of the moon, and has driven 345.059 meters accumulatively.[27]
At 18:43 on December 20, the Yutu II lunar rover received the normal telemetry signal, successfully waked up independently, and the scientific payload started normally to continue the journey of walking on the moon.[28]
2020
At 17:55 on January 19, Yutu 2 successfully woke up to the light and entered the 14th day of the month.[29]
At 17:55 on February 17, "Yutu 2" ended its "dormancy" on the night of the moon, successfully woke up from the light, and entered the working period of the 15th day of the month. The rover will move northwestward and then southwestward to synchronously drive and explore at the new target point."Yutu 2" has traveled 367.25m on the moon.[7][30]
At 20:6 on March 1, the Yutu II lunar rover successfully completed its scientific exploration work in the day of the 15th month and went into a lunar night sleep.[31]
At 7:30 and 23:38 on March 18, "Yutu II" and the lander respectively ended their "sleep" on the moon and night, woke up autonomously under the sun, and entered the daytime working period of the 16th month.As of 24:00 on March 18, the Yutu II lunar rover had been on the moon for 440 days, continuously breaking the record of the survival time of the lunar rover on the moon surface.[32]
At 8:25 on March 31, the Yutu II lunar rover successfully completed the day and day scientific exploration work in the sixteenth month, completed the moon night setup, and entered the dormant period of the sixteenth month night.During the day of the 16th month, the scientific payload carried by the Yutu II lunar rover started normally, and continued to carry out scientific missions such as infrared imaging of the moon surface, neutral atom measurement, and exploration of the lunar subsurface, lunar soil, and shallow structure of the moon shell along the patrol route.[33]
At 11:53 on May 16, the Yutu 2 lunar rover ended its cold and long dormancy on the moon night, woke up by light, and ushered in the working period of the day in the 18th month.[2]
On June 15, the Chang'e-4 lander and the Yutu 2 lunar rover ended their cold and long sleep on the moon at 13:49 and 054, respectively. They were awakened by light and entered the daytime working period of the 19th month.[34]
On June 28, it was reported that the Chang'e-4 lander and the Yutu 2 lunar rover ended their daytime work in the 19th month at 1:00 on June 28 and 16:23 on June 27, respectively. They completed the lunar night mode setting according to the ground instructions and went into lunar night sleep.As of the day of the 19th month, the accumulated mileage of the Yutu 2 lunar rover was 463.26 meters.[35]
On July 15, it was reported that the Chang'e-4 and Yutu 2 lunar rovers woke up at 5:48 on July 15 and 12:53 on July 14, respectively. The successful wake-up of the two vehicles marked that "Chang'e" joined hands with "Yutu" to enter the daytime working period of the 20th month, constantly creating new records.By July 15, 2020, the Chang'e-4 lander and the Yutu 2 rover had passed 559 Earth days.[36]
On August 13, the Chang'e-4 lander and the Yutu 2 lunar rover ended their sleep at 14:54 on August 13 and 20:34 on August 12, respectively. They were awakened by light and entered the daytime working period of the 21st month.The working conditions of the two instruments are normal, and the energy is balanced. Continue the exploration of the back of the moon.[4]
At 18:57 on October 10, the "Yutu II" lunar rover woke up.During the day of this month, the Yutu II lunar rover willbasaltDistribution area or high reflectivityImpact craterThe two locations are located in the northwest of the current detection point.In this route, there is a rock block with a diameter of about 30cm. The Yutu II lunar rover will use the infrared imaging spectrometer to select an opportunity to detect the rock block.[37]
At 12:00 on October 23, the Yutu II lunar rover completed its work in the day of the 23rd month.The moon night mode has been set according to the ground command, and the moon night sleep has been entered.So far, Chang'e-4 lander and Yutu 2 lunar rover have successfully operated on the back of the moon for 660 earth days, and the Yutu 2 lunar rover has traveled a total of 565.9 meters.The Yutu II lunar rover went tobasaltDistribution area and high reflectivityImpact craterThe two positions are located in the northwest of the rover.In this route, the infrared imaging spectrometer carried out spectral detection on a rock block with a diameter of about 30 cm.The scientific research team is conducting in-depth research on the detection data.In the 23 month day scientific exploration, the lunar surface neutron and radiation dose detector of the lander carried out the first lunar surface field particle radiation environment detection in the world, obtained valuable first-hand scientific data, and the research results were published in the journal ScienceAdvance.[38]
At 10:17 on November 9, the Yutu 2 lunar rover ended its dormancy on the night of the moon and was awakened by light, ushering in the 24th day of the month. Chang'e 4 has worked successfully for 677 Earth days.[39]
At 3:10 on November 22, the Yutu II lunar rover completed its work in the day of the 24th month and went into sleep on the moon night.Chang'e-4 has been working on the back of the moon for 690 earth days, with a cumulative mileage of 589.6 meters.The Yutu II lunar rover continued to move towards the basalt direction and the impact crater area with high reflectivity during the 24th day.The infrared imaging spectrometer on the Yutu II lunar rover acquired the spectral and mineralogical characteristics of the lunar soil and rock on the patrol exploration route, providing important support for revealing the material composition of the landing area, especially the deep lunar material composition contained in the Antarctic Aitken Basin, the largest impact basin on the moon.Scientific achievements were published in the international journal Remote Sensing.The planetary science team of Shandong University, together with the research team of the Shanghai Institute of Technology and Physics, the Institute of Geochemistry and the Space Center of the Chinese Academy of Sciences, has observed the spectral "recoil" effect and“red shift”It was found that the mineral composition of lunar soil in Chang'e-4 landing area was relatively uniform after Yutu 2 walked 448m on the moon surface.[40]
At 5:00 on December 22 and 19:22 on December 21, the Chang'e-4 lander and the Yutu 2 rover completed the day work in the 25th month, completed the moon night mode setting according to the ground instructions, and entered the moon night sleep.Chang'e-4 lander and Yutu 2 rover have been working on the moon for 719 days, and the rover has driven a total of 600.55 meters.[41]
2021
Route map of Chang'e-4 during the first 34 months
On January 3, Chang'e-4 lander and Yutu 2 lunar rover had been working on the moon for 731 days. The rover had driven 600.55 meters and produced scientific achievements continuously.[5]
At 10:29 on January 7, the Yutu II lunar rover woke up, and the lander woke up at 03:13 on January 8.As of January 8, 2021, Chang'e-4 has worked for 736 Earth days.[42]
On March 8, Chang'e-4 lander and Yutu 2 rover completed wake-up setup, ushering in the 28th day of the month.As of March 8, 2021, Chang'e-4 has successfully operated on the back of the moon for 795 Earth days[48]。
At 21:43 and 3:54 on April 6, Chang'e-4 lander and Yutu 2 lunar rover respectively ended their dormancy at the moon and night, woke up automatically by light, and entered the daytime working period of the 29th month;Chang'e-4 has spent 825 Earth days on the back of the moon[49-50]。
On September 29, on the eve of the 72nd birthday of the motherland, the Chang'e-4 lander and the Yutu 2 rover had been in orbit for more than 1000 days, continuing to set new records for work on the back of the moon.The Chang'e-4 lander and the Yutu 2 lunar rover are in good working condition, and their loads are working normally. They continue to carry out scientific exploration.As of September 29, 2021, the Yutu 2 lunar rover has driven 839.37 meters in total and obtained 3632.01GB of scientific data in total, which is the 34th lunar night. Scientific achievements will be released in time.[51]
2022
Daytime driving route map of Yutu 2 in the first 44 months[59]
Near midnight on January 6, on the third anniversary of Chang'e-4's landing on the moon, the Yutu 2 lunar rover traveled more than 1000 meters, reaching 1003.9 meters, which was in the daytime working period of the 38th month. The working condition was normal.[53-54]
At the end of April, the Yutu II lunar rover entered its 41st lunar night of dormancy, with a total mileage of 1142.387 meters[57]。
May 1, according toNational Space AdministrationAccording to the Lunar Exploration and Space Engineering Center, the Yutu II lunar rover has traveled more than 1181 meters in total.[58]
On July 6, the Yutu 2 lunar rover and lander of the Chang'e 4 mission completed their sleep settings at 19:14 on July 5 and 6:00 on July 6, respectively, completing the work in the day of the 44th month and entering the sleep in the 44th night of the month.The accumulated mileage of the rover on the back of the moon is 1239.88 meters.[59]
To extend“Magpie bridge”The life span of the relay star began in the 44th day of the month, and the ground controllers decided to keep Yutu 2 in place to verify the law of angular momentum accumulation under different postures of "Queqiao".After testing for nearly two months and days, the ground staff finally grasped the relevant laws, designed a set of "Magpie Bridge" angular momentum management mode that can give consideration to the moon and day work of the Jade Rabbit, and defined the switching principles and expected benefits of various postures under the angular momentum management mode.The on orbit life of the "Magpie Bridge" has been greatly extended, and the Yutu 2 can set off again to explore more unknown areas of the moon back.[60]
The gravel heap in the southwest became the first stop after the restart of the Jade Rabbit adventure.With the approach to the gravel pit, there are more potholes and gravels along the road.In the morning of the day of the 46th month, the northwest of the road ahead of the Yutu No. 2 target was overexposed. For safety reasons, the drivers carefully controlled Yutu to walk in small steps and zigzag lines, bypassing the dotted potholes.[60]
In the afternoon of January and Sunday, the drivers got the news that a deep space TT&C station was going to be offline for a long time, resulting in the reduction of available TT&C arcs when waking up in the day of the next month, which meant that the sleeping attitude roll angle control of Dayu Rabbit 2 was only 2 degrees this month, which brought great challenges to the drivers.We carefully selected the sleeping place, repeatedly calculated and planned the route to the rubble heap, and boldly designed a 2-step sleeping road approaching 10 meters in the afternoon of the month and day.When the rolling angle was displayed as - 0.2 degrees, the drivers' superb "driving skills" were verified again, and the posture of Yutu II was perfectly within the expected design range.[60]
Later, the drivers controlled Yutu 2 to conduct color imaging of the rubble piles 10 meters away, and finally got a close view of the rubble piles.[60]
Day of the 46th month: Close up panorama of gravel pile[60]
2023
On January 3, the fourth anniversary of Chang'e-4's landing on the moon back, the vehicle reached 1455 meters and the working condition was normal, creating many remarkable achievements[61]。
On the same day,China Aerospace Science and Technology Group Co., LtdThe 2023 model work conference was held, and China will comprehensively promote the fourth phase of the lunar exploration project and the planetary exploration project,Develop Chang'e-7 and other modelswork[63][83]。
On January 21, the National Space Administration released the latest engineering pictures of Yutu II.[62]During the day of the 50th month, when the Yutu II lunar rover drove to LE05005, the panoramic camera took pictures of multiple impact craters of different sizes[82]。
technological innovation
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Weight reduction driving
Compared with Yutu, which weighs 137 kg, Yutu 2 has replaced the mechanical arm with a particle excited X-ray spectrometer with a neutral atom detector, which is a Sino Swiss cooperative instrument. Therefore, it is 2 kg lighter, making it the lightest lunar rover in history as of January 2019.The terrain on the back of the moon is rugged, and Yutu II is facing greater challenges.The scientific research team has replaced it with a special mesh wheel, which is light, strong, shock absorption, and integrated with drive and transmission. We hope it will be more independent, more robust, more reliable, and can go farther on the moon[68]。
Autonomous sleep
Due to the complex environment on the back of the moon, researchers believe that the ground control sleep mode used by the Yutu is difficult to adapt.Jia Yang also worked hard with the Yutu 2 research team and put forward an independent sleep plan to ensure that Yutu 2 can sleep independently according to the light conditions even without ground support when the sun is about to set[68]。
Reliable wake-up
In terms of wake-up function, the scientific research team has also improved the Yutu 2.In order to get the appropriate equipment temperature when the patroller wakes up, they put forward a car body heading adjustment scheme. No matter what kind of mountains are in the direction of the sun rising, enough equipment heating time can be ensured to achieve reliable wake-up[68]。
Record breaking
At 18:43 on December 20, 2019, "Yutu II" became the lunar rover with the longest working time on the moon surface.[8]
Multimode operation
The developer has defined seven working modes for Yutu II patrol, namely, perception, movement, detection, charging, security, day to night, sleep, and night to day, to cope with different working environments and adapt to different working conditions.
The Yutu II lunar rover will continue to move towardsbasaltThe distribution area (about 1.2 km away from the inspector, located near 177.5389 ° E and 45.4119 ° S) moves forward, which is located northwest of the current detection point[50]。
"Chang'e, Yutu" wakes up successfully and enters the 29th day of the month
▲ Recent basalt coverage area (red line area) | Source: China's lunar exploration project
In April 2021, the lunar day plan of Yutu II lunar rover will be carried out:
Panoramic camera carries out ring shot detection;
Calibration and scientific detection of infrared imaging spectrometer;
The neutral atom detector (ASAN) carries out scientific detection;
During driving, the lunar radar carries out synchronous detection on the path area[50]。
Results release
2020
On February 27,National Astronomical Observatory, Chinese Academy of SciencesThe scientific research team made major discoveries in the field of deep space exploration of the moon in China. Using the lunar radar carried on the Chang'e-4 Yutu 2 lunar rover, the research team revealed for the first time the geological stratification structure within the depth of 40 meters below the landing area on the back of the moon, and found that the underground material was composed of low consumption lunar soil material and a large number of rocks of different sizes.This research result is of great significance for understanding the impact process's impact on the lunar surface, the scale and history of volcanic activity, etc[43]。
On April 24, the fifth“China Aerospace Day”At the launching ceremony, Wu Weiren, academician of the Chinese Academy of Engineering and chief designer of the lunar exploration project, introduced that the Yutu II lunar rover had set a world record for the longest lunar surface work, and obtained the first geological profile of the back of the moon, which is nearly 500 meters long and 50 meters deep, as well as valuable data such as lunar mineral composition and space environment[44]。
2021
In December, the Yutu 2 lunar rover carried by China's Chang'e-4 found special residues that were not originally part of the moon in the lunar impact crater for the first time.[52]Yutu 2 found a "mysterious hut" on the moon and will go to explore it.
2022
In February, according to the research team led by Dr. Xiao Zhiyong of Sun Yat sen University of the Chinese Science Journal, a paper was published, which introduced the research on the discovery of transparent glass beads with a diameter of centimeter on the back of the moon by the Yutu 2 lunar rover. This kind of glass beads was the first time found internationally.[55]
On April 17, Harbin University of Technology released a news that the State Key Laboratory of Robotics and Systems of the university, together with several units, estimated the mechanical properties of lunar soil based on the information of the interaction between the wheels of the Yutu II lunar rover and the moon surface and the ground mechanical model. The results showed that the pressure bearing properties of the lunar soil weathering layer were similar to those of dry sand and sandy loam on the earth,Compared with the typical lunar soil in the American Apollo Program, it has stronger pressure bearing characteristics.[56]
Honors won
Announce
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Honor recognition
2019
On January 11, the Central Committee of the Communist Party of China, the State Council and the Central Military Commission sent congratulatory messages on the success of the Chang'e-4 mission of the lunar exploration project[3]。
Wu Weiren, Chief Designer of China's Lunar Exploration Project and Academician of the Chinese Academy of Engineering, receives the medal
November 25, UKRoyal Aeronautical SocietyThe 2019 annual award ceremony was held in London, and the Chang'e-4 mission team won the only global team gold award in 2019.This award is also the first award given to Chinese projects by the Royal Aeronautical Society since its founding 153 years ago.
On December 5, at the 3rd International Lunar Village Seminar held in Tokyo, Japan, the "China Chang'e-4 Lunar Exploration Mission" won the "Excellent Lunar Exploration Mission Award" issued by the Lunar Village Association, becoming the first batch of award-winning projects.
2020
On January 11,Academician of CASandAcademician of Chinese Academy of EngineeringChang'e-4 achieved the first soft landing of a human probe on the moon back in the "Ten Major Advances in Chinese Science in 2019" voted by the vote, and "the preliminary evidence of detecting the exposure of the lunar mantle material" ranked first[76][79]。
world record
On January 3, 2019, the Chang'e-4 probe carrying Yutu 2 completed its first landing on the back（Guinness World Records）。[81]
As of March 9, 2022, China's "Yutu II" lunar rover has run on the moon for 40 lunar days (one lunar day is about 28 Earth days), becoming the Guinness World Record for the longest running lunar rover.
Commemorative Stamp
On November 1, 2019,China PostA set of five commemorative stamps of "Scientific and Technological Innovation (II)" were issued, of which the first "Chang'e-4" picture shows the lunar exploration project "Chang'e-4" lander, "Yutu 2" patrol, "Queqiao" relay star, etc[78]。
Chang'e-4 mission is the first time to realize the soft landing and patrol detection on the back of the moon of a human probe, the first time to realize the relay communication between the back of the moon and the earth, and the first time to realize low-frequency radio astronomy observation and research, which will open a new chapter in human lunar exploration.
The Chang'e-4 probe landed atAntarctica Aitken BasinOfVon Karman impact craterIt is a huge impact crater on the back of the moon and the largest and deepest basin of solid objects in the entire solar systemirregularity"Yutu No. 2" is facing competition“Yutu”Greater challenges[9]。（XinhuaComment)
The back of the moon is older than the front,Von Karman impact craterIts material composition and geological age are representative, which is of great value to the study of the early history of the moon and the solar system.The back of the moon is also a rare quiet place, shielding the radio signal interference from the earth. The low-frequency radio astronomy observation here can fill the gap in the low-frequency observation segment in the field of radio astronomy, providing possibility for the study of the sun, planets and extrasolar objects, and will also provide important data for the study of star origin and nebula evolution[47]。（《Beijing Evening News》Comment)
Yutu II is the first spacecraft to land on the back of the moon, and it has become another milestone in the development of China's space industry[64]。Yutu II has become another milestone in the development of China's space industry, opening the era for Chinese people to explore the mysteries of the universe in deep space, and marking China's entry into the ranks of countries with deep space exploration capabilities[64]。（GuangmingComment)
Chang'e-4 mission is the first mission of the fourth phase of China's lunar exploration project. It is the first time in human history that a spacecraft has achieved soft landing and patrol survey on the back of the moon, achieved relay communication between the back of the moon and the earth for the first time, and carried out significant international cooperation with many countries and international organizations.This is another major achievement of the space front under the gracious care and strong leadership of the Party Central Committee with Comrade Xi Jinping at the core, which insists on self-reliance and independent innovation. It is one of the important signs of China's progress from a space power to a space power. It is a new benchmark and a new height for the Chinese people to climb the world's science and technology peak in the new era,It is another outstanding contribution made by the Chinese nation to mankind's exploration of the mysteries of the universe[3]。（CPC Central Committee、the state councilThe Central Military Commission congratulated and commented)
