Wikipedia

Yutu-2

Yutu-2 (Chinese: 玉兔二号; pinyin: Yùtù Èrhào) is the robotic lunar rover component of CNSA's Chang'e 4 mission to the Moon, launched on 7 December 2018 18:23 UTC, it entered lunar orbit on 12 December 2018 before making the first soft landing on the far side of the Moon on 3 January 2019. Yutu-2 is currently operational as the longest-lived lunar rover[8] after it eclipsed (on 20 November 2019) the previous lunar longevity record of 321 Earth days held by Soviet Union's Lunokhod 1 rover. Yutu-2 is the first lunar rover ever to have traversed the far side of the Moon. By January 2022, it had travelled a distance of more than 1,000 metres (3,300 ft) along the Moon's surface.[9][10] Data from its ground penetrating radar (GPR) has been used by scientists to put together imagery of multiple layers deep beneath the surface of the far side of the Moon.[11] As of September 2024, the Yutu-2 was still active.[12]

Yutu-2
Yutu-2 rover on the Moon as seen by the Chang'e 4 lander
Mission typelunar rover
OperatorCNSA
Mission duration3 months (planned)[1]
Current: 5 years, 10 months, 9 days
Spacecraft properties
Launch massRover: 140 kg[2]
Landing mass140 kg
Dimensions1.5 × 1.0 × 1.0 m[3]
Start of mission
Launch date7 December 2018, 18:23 UTC[4]
RocketLong March 3B[5]
Launch siteXichang Satellite Launch Center
Lunar rover
Landing date3 January 2019, 02:26 UTC[6]
Landing siteVon Kármán crater in the South Pole-Aitken Basin
Distance driven1.596 km (0.992 mi)
as of 4 May 2024[7]

Overview

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Mockup of Yutu-2 rover.

The total landing mass is 1,200 kg (2,600 lb).[2] Both the stationary lander and Yutu-2 rover (literally: "Jade Rabbit") are equipped with a radioisotope heater unit (RHU) to maintain their subsystems during the long lunar nights,[13] while electrical power is generated by solar panels.

After landing, the lander extended a ramp to deploy the Yutu-2 rover to the lunar surface.[14] The rover measures 1.5 × 1.0 × 1.0 m (4.9 × 3.3 × 3.3 ft) with a mass of 140 kg (310 lb),[2][3] and is propelled by six wheels. Yutu-2 was manufactured in Dongguan, Guangdong province.[13] The rover is an improvement of the first Yutu rover from 2013; while its nominal operating time is three months,[1] Chinese mission engineers hoped it would operate for "a few years", extending beyond its original planned mission.[15]

The landing craft touched down at 02:26 UTC on 3 January 2019, becoming the first spacecraft to land on the far side of the Moon, and the rover deployed about 12 hours later.

Science payloads

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  • Panoramic Camera (PCAM), is installed on the rover's mast and can rotate 360°. It has a spectral range of 420 nm–700 nm and it acquires 3D images by binocular stereovision.[16]
  • Lunar penetrating radar (LPR), is a ground penetrating radar with a probing depth of approximately 30 m with 30 cm vertical resolution, and more than 100 m with 10 m vertical resolution.[16]
  • Visible and Near-Infrared Imaging Spectrometer (VNIS), for imaging spectroscopy that can then be used for identification of surface materials and atmospheric trace gases. The spectral range covers visible to near-infrared wavelengths (450 nm – 950 nm).
  • Advanced Small Analyzer for Neutrals (ASAN), is an energetic neutral atom analyzer provided by the Swedish Institute of Space Physics (IRF). It will reveal how solar wind interacts with the lunar surface, which may help determine the process behind the formation of lunar water.[17]

Cost

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According to Wu Yanhua, the deputy director of the project, the cost of the entire mission was "close to building one kilometer of subway", which can vary from 500 million yuan (about 72.6 million U.S. dollars) to 1.2 billion yuan (about 172.4 million dollars).[18]

Landing site

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The landing site is within the Von Kármán crater[19] (180 km or 110 mi diameter) in the South Pole-Aitken Basin on the far side of the Moon, which was previously unexplored by landers.[20][21] The site has symbolic as well as scientific value: Theodore von Kármán was the PhD advisor of Qian Xuesen, the founder of the Chinese space program.[22]

Operations and results

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The first panorama from the far side of the moon

A day after landing, Yutu-2 went into hibernation for its first lunar night and it resumed activities on 10 January 2019, with all instruments operating nominally. During its first full lunar day, the rover travelled 120 m (390 ft), and on 11 February 2019 it powered down for its second lunar night.[23][24] In May 2019, it was reported that Chang'e 4 has identified what appear to be mantle rocks on the surface, its primary objective.[25][26][27]

In November 2019, Yutu 2 broke the lunar longevity record previously held by the Soviet Union's Lunokhod 1 rover[8] which operated on the lunar surface for eleven lunar days (321 Earth days).[28]

In February 2020, Chinese astronomers reported, for the first time, a high-resolution image of a lunar ejecta sequence, and, as well, direct analysis of its internal architecture. These were based on observations made by the rover's Lunar Penetrating Radar (LPR).[29][30]

Data from its two-channel ground penetrating radar (GPR) has constructed an image of multiple layers beneath the surface to a depth of 300 meters.[11]

Gel-like Substance

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In September 2019, the Yutu-2 rover found a mysterious, unusual "gel-like" substance on the lunar surface inside a small crater in the central region of the Von Kármán crater on the south pole of the far side of the moon.[31] Further analysis found that the substance resembled rock melted by a lunar impact. Thus, the research indicates that the bright, green material is, in fact, rock that was melted by the heat generated by a meteorite impact on the Moon. [32]

Mystery Hut

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In December 2021, the rover pictured what appeared to be a particularly prominent boulder, dubbed the "Mystery Hut" (神秘小屋), or "Moon Cube",[33][34] which it was intended to explore in the following lunar days (earth months).[35][36] On 7 January 2022, news reported that the rover reached the "Mystery Hut" after traveling for a month, and found it to be "irregularly shaped rock";[37] resembling a rabbit, with a smaller nearby rock like a carrot, making a fitting discovery for the Yutu (Jade Rabbit).[38]

 
The routing path of the Yutu-2 rover.


See also

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References

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  1. ^ a b China says it will launch 2 robots to the far side of the moon in December on an unprecedented lunar exploration mission Archived 9 December 2018 at the Wayback Machine. Dave Mosher, Business Insider. 16 August 2018.
  2. ^ a b c Chang'e 3, 4 (CE 3, 4) Archived 20 March 2018 at the Wayback Machine. Gunter Dirk Krebs, Gunter's Space Page.
  3. ^ a b This is the rover China will send to the 'dark side' of the Moon Archived 31 August 2018 at the Wayback Machine. Steven Jiang, CNN News. 16 August 2018.
  4. ^ "CNSA". China National Space Administration (in Chinese (China)). Archived from the original on 10 December 2018. Retrieved 8 December 2018.
  5. ^ Launch Schedule 2018 Archived 16 August 2018 at the Wayback Machine. SpaceflightNow, 18 September 2018.
  6. ^ Barbosa, Rui (3 January 2019). "China lands Chang'e-4 mission on the far side of the Moon". Nasaspacefight. Archived from the original on 3 January 2019. Retrieved 3 January 2019.
  7. ^ "中国探月工程立项20年 回顾"嫦娥"奔月之旅" (in Simplified Chinese). 央视新闻. 2024-05-04. Retrieved 2024-05-05.
  8. ^ a b David, Leonard (18 December 2019). "China's Farside Moon Rover Breaks Lunar Longevity Record". Space.com.
  9. ^ "Moon 'mystery hut' is just a rabbit-shaped rock, Chinese rover finds". Space.com. 11 January 2022. Retrieved 12 January 2022.
  10. ^ "China's lunar rover Yutu 2 is on a mission to investigate mystery object on far side of the moon". 2021-12-05.
  11. ^ a b "China's Yutu 2 rover reveals deep layers below far side of the moon". Space.com. 2023-08-24.
  12. ^ Jones, Andrew (2024-09-19). "China's Yutu 2 rover still going strong after nearly 6 years on the far side of the moon". Space.com. Retrieved 2024-10-20.
  13. ^ a b China Shoots for the Moon's Far Side. (PDF) IEEE.org. 2018.
  14. ^ Xu, Luyuan (15 June 2018). "How China's lunar relay satellite arrived in its final orbit". The Planetary Society. Archived from the original on 17 October 2018.
  15. ^ China's Chang'e 4 spacecraft to try historic landing on far side of Moon 'between January 1 and 3' Archived 2 January 2019 at the Wayback Machine. South China Morning Post. 31 December 2018.
  16. ^ a b The scientific objectives and payloads of Chang'E−4 mission. (PDF) Yingzhuo Jia, Yongliao Zou, Jinsong Ping, Changbin Xue, Jun Yan, Yuanming Ning. Planetary and Space Science. 21 February 2018. doi:10.1016/j.pss.2018.02.011
  17. ^ Andrew Jones (16 May 2016). "Sweden joins China's historic mission to land on the far side of the Moon in 2018". GBTimes. Archived from the original on 6 October 2018. Retrieved 12 January 2018.
  18. ^ China's latest Moon mission costs about as much as building 1 km of subway – Headlines, features, photo and videos from ecns.cn|china|news|chinanews|ecns|cns
  19. ^ China's Journey to the Lunar Far Side: A Missed Opportunity? Paul D. Spudis, Air & Space Smithsonian. 14 June 2017.
  20. ^ Ye, Peijian; Sun, Zezhou; Zhang, He; Li, Fei (2017). "An overview of the mission and technical characteristics of Change'4 Lunar Probe". Science China Technological Sciences. 60 (5): 658. Bibcode:2017ScChE..60..658Y. doi:10.1007/s11431-016-9034-6. S2CID 126303995.
  21. ^ "China Plans First Ever Landing on the Lunar Far Side". Space Daily. 22 May 2015. Archived from the original on 26 May 2015. Retrieved 26 May 2015.
  22. ^ "Hsue-Shen Tsien". Mathematics Genealogy Project. Archived from the original on 9 December 2018. Retrieved 7 December 2018.
  23. ^ Jones, Andrew (11 February 2019). "Chang'e-4 powers down for second lunar night". SpaceNews. Retrieved 1 August 2019.
  24. ^ Caraiman, Vadim Ioan (11 February 2019). "Chinese Lunar Probe, Chang'e-4, Goes Standby Mode For The Second Lunar Night on The Dark Side of The Moon". Great Lakes Ledger. Retrieved 1 August 2019.
  25. ^ Ouyang, Ziyuan; Zhang, Hongbo; Su, Yan; Wen, Weibin; Shu, Rong; Chen, Wangli; Zhang, Xiaoxia; Tan, Xu; Xu, Rui (May 2019). "Chang'E-4 initial spectroscopic identification of lunar far-side mantle-derived materials". Nature. 569 (7756): 378–382. Bibcode:2019Natur.569..378L. doi:10.1038/s41586-019-1189-0. ISSN 1476-4687. PMID 31092939. S2CID 205571018.
  26. ^ Strickland, Ashley (2019-05-15). "Chinese mission uncovers secrets on the far side of the moon". CNN. Retrieved 2019-05-16.
  27. ^ Rincon, Paul (15 May 2019). "Chang'e-4: Chinese rover 'confirms' Moon crater theory". BBC News. Retrieved 1 August 2019.
  28. ^ Howell, Elizabeth (December 19, 2016). "Lunokhod 1: 1st Successful Lunar Rover", Space.com. Retrieved May 31, 2018.
  29. ^ Chang, Kenneth (26 February 2020). "China's Rover Finds Layers of Surprise Under Moon's Far Side – The Chang'e-4 mission, the first to land on the lunar far side, is demonstrating the promise and peril of using ground-penetrating radar in planetary science". The New York Times. Retrieved 27 February 2020.
  30. ^ Li, Chunlai; et al. (26 February 2020). "The Moon's farside shallow subsurface structure unveiled by Chang'E-4 Lunar Penetrating Radar". Science Advances. 6 (9): eaay6898. Bibcode:2020SciA....6.6898L. doi:10.1126/sciadv.aay6898. PMC 7043921. PMID 32133404.
  31. ^ Andrew Jones (2019-09-03). "China's Lunar Rover Just Found Something Weird on the Far Side of the Moon". livescience.com. Retrieved 2021-12-08.
  32. ^ Rabie, Passant (2020-07-11). "Scientists finally figured out what that gel-like stuff is on the Moon". Inverse. Retrieved 2024-07-12.
  33. ^ Shannon Stirone (8 December 2021). "Moon Cube and Mysteries of the Solar System". The New York Times. Retrieved 27 December 2021.
  34. ^ Kelvey, Jon (8 December 2021). "Look: Chinese Rover Spots a "Moon Cube," and Opens a New Lunar Mystery - While almost certainly a boulder or two, the enigmatic Moon Cube is nevertheless fascinating, and could help scientist understand how to live on the Moon". Inverse. Retrieved 27 December 2021.
  35. ^ Jones, Andrew (5 December 2021). "China's Yutu 2 rover spots cube-shaped 'mystery hut' on far side of the moon". Space.com. Retrieved 6 December 2021.
  36. ^ Kooser, Amanda (5 December 2021). "China moon rover will investigate cube-shaped 'mystery' object on lunar far side - Is that a boulder? Or something else?". CNET. Retrieved 6 December 2021.
  37. ^ Dvorsky, George (7 January 2022). "'Mysterious Hut' Spotted on Far Side of the Moon Is a Huge Disappointment - It took China's Yutu 2 rover a full month to reach its underwhelming destination". Gizmodo. Retrieved 7 January 2022.
  38. ^ Chang, Kenneth (7 January 2022). "Moon Cube Mystery: Chinese Rover Finds It's Just a Rock - A blurry image thatJChina's space program had called the "mystery hut" was a result of camera angle, light and shadow". The New York Times. Retrieved 7 January 2022.
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