Jade Bunny 2

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Communication with the far side of the moon with lander and rover on the relay - Satellite Elsterbrücke ( Queqiao ) (Scheme)

Jade Rabbit 2 ( Chinese  玉兔 二號  /  玉兔 二号 , Pinyin yùtù èr hào , English Jade Rabbit 2 ) is the rover of the Chinese moon mission Chang'e-4, which started on December 7, 2018 . On December 20, 2019, the 20th anniversary of the reunification with Macau , Jade Rabbit 2 broke the 49-year-old record of Lunochod 1 as the longest vehicle on the lunar surface. On August 25, 2020, the 7th day of the 7th month according to the lunar calendar, i.e. the one day of the year on which the cowherd and weaver meet across the Elsternbrücke , the rover had spent exactly 600 days on the moon.

mission

After landing in the Von Kármán Crater of the South Pole Aitken Basin , the rover left the lander via a ramp on January 3, 2019 at 10:22 p.m. Beijing time (14:22 GMT ). He's the first to ride the back of the moon . The rover of the Chinese Space Agency (CNSA) is the second moon rover in China after the jade hare of the Chinese moon mission Chang'e-3, which started on December 1, 2013 . In Chinese mythology, the word jade hare ( 玉兔 , yùtù ) describes the companion of the moon goddess Chang'e (see hare in the moon ). Wu Weiren has been the Technical Director of the People's Republic of China's Lunar Program since 2010 . At the manufacturing company of Chang'e-4, the Chinese Academy of Space Technology, Sun Zezhou has been the chief designer for the lunar probes since April 2016 . The rover itself is looked after by three teams:

  • The science team (科学 团队) analyzes the data transmitted by the rover to the earth via the Elsternbrücke relay satellite , points out the things that still need to be measured and suggests the next stop for the rover.
  • The planning team (计划 团队) works out a measurement plan according to the needs of the science team, determines the measurement points and determines the route by which the rover will get to these points.
  • The control team (操控 团队) writes the command lines for the rover and thus ensures that Jadehase 2 takes the desired measurements at the desired points.

When the moonlit night approaches, Jadehase 2 looks for a previously selected sleeping place. There it turns with the front to the south so that the immovable solar module on the left in the direction of travel faces east. The heating, fed by radionuclide heating elements with a total of 120 W power, is activated from the earth. Then the rover folds the mast with the parabolic antenna and the three-dimensional panorama camera back into its housing and folds the movable solar cell wing over it to close the housing and protect itself from the cold.

If the sun rises again after 14 days and the power supplied by the left solar cell wing exceeds a certain level, the rover wakes up automatically. His central computer switches on, the movable solar cell wing and the mast fold out, and Jadehase 2 independently establishes a radio link with the relay satellite Elsternbrücke. The control team on Earth turns the rover in the desired direction, then it begins its work.

During the many months that Jadehase 2 spent exploring Von Kármán Crater, the technicians on the planning and control teams had gained ample experience in controlling a vehicle on an alien celestial body. With the Tianwen-1 mission to Mars , the requirements are significantly higher due to the signal transit time of up to 40 minutes, which is why the technicians who are to define and program the route of the Mars rover in the Beijing Space Control Center were selected from the experienced lunar teams.

construction

The landing site of Chang'e-4 (star) with ejecta from Finsen (yellow) and Von Kármán L (green).

The dimensions of the Chang'e 4 rover are approx. 1.5 × 1 × 1 meters and the weight is 140 kg. The ground clearance is 30 cm, it can cope with inclines of up to 20 ° and climb over obstacles of up to 20 cm. The terrain in Von Kármán Crater is more challenging than in Mare Imbrium , where Chang'e-3 landed. It often happens that the rover is in the way of larger boulders, whereupon it automatically initiates complex, multi-stage evasive maneuvers in order to avoid the obstacle as closely as possible and not be distracted too far from its path. As a result, Jadehase 2 moves noticeably slower than its predecessor despite its basic speed of 5.5 cm / s. On March 31, 2019, Liu Dianfu (刘殿富), the head of the development group responsible for the rover's locomotion system, explained that if there were no unforeseen incidents, Jadehase 2 could continue to work for at least 1 year. This then also happened. As the rover on 25 August 2020 at the end of the 21st day on the moon, in the sleep mode passed, both the vehicle was still working properly and all payloads, the Rover struggled in a northwesterly direction from the stray field of Finsen crater out . By this time he had covered 519 m without getting stuck.

The rover has the following payloads:

  • a panoramic camera (PCAM) to obtain three-dimensional images of the landing site and the explored terrain for a study of surface morphology and geological structure
  • a ground penetrating radar ( Lunar Penetrating Radar , LPR), identical in construction to that of its predecessor Jadehase , for measuring the lunar underground structure
  • an infrared spectrometer ( Visible and Near-Infrared Imaging Spectrometer , VNIS) for the investigation of the mineralogical composition of the lunar surface material. Specifically, the search is for ores that can be mined in the future.
  • a detector for neutral atoms ( Advanced Small Analyzer for Neutrals , ASAN, Sweden ) for observing energy- neutral atoms and positive ions, i.e. the radiation exposure at the South Pole

Unusual observations

During the 17th working day on the moon (April 16-30, 2020), Jade Hare 2 had discovered a shallow crater about 1.3 m in diameter and barely 20 cm deep, in the center and south-eastern flank of which there was material that the sunlight unusually strong and clearly different from the surrounding regolith. When the rover went into sleep mode at the end of the day, it was ten feet from the crater. Since the resources of the Chinese deep space network were largely withdrawn from the lunar program in May / June 2020 due to the Tianwen-1 mission to Mars, which was being prepared at the time, Jade Rabbit 2 was able to return to the lunar program on May 16, 2020 at sunrise Work mode passed, initially do not approach the crater any further. On June 13, 2020, the renovation work at the Kashgar and Giyamusi deep-space stations was completed, and when the sun rose again on the far side of the moon on June 15, the rover began to examine the crater with its infrared spectrometer. During the 19th lunar day (June 15 to 27, 2020), he took two pictures of the material inside the crater under two different incidence of light situations and then turned back to the northwest to find a suitable sleeping place for the coming lunar night to search.

Web links

Individual evidence

  1. ↑ “玉兔 二号” ： 成 月 面 工作 时间 最长 月球 车. In: clep.org.cn. December 23, 2019, accessed December 23, 2019 (Chinese). Lunochod 1, however, had covered a much longer distance with 10.54 km.
  2. ↑ a b “来自 星星 的 七夕 大礼” ： 天 问 一号 距离 地球 超 1000 万 公里 ， 嫦娥 四号 工作 满 600 天！ In: spaceflightfans.cn. August 25, 2020, accessed August 25, 2020 (Chinese).
  3. ↑ 蔡金 曼: 嫦娥 四号 着陆 器 与 巡视 器 顺利 分离 玉兔 二号 在 月 背 背 留下 人类 探测器 的 第一 道 印迹. In: cnsa.gov.cn. January 4, 2019, accessed December 23, 2019 (Chinese).
  4. ↑ 德 先生: 孙泽洲 ： 嫦娥 四号 传 回 月球 近景 图 离不开 他 13 年 的 付出 ， 月 背 软着陆 为 中国 实现 载人 登月 打下 契机. In: zhuanlan.zhihu.com. January 8, 2019, accessed May 5, 2019 (Chinese).
  5. ↑ “玉兔 二号” ： 成 月 面 工作 时间 最长 月球 车. In: clep.org.cn. December 23, 2019, accessed December 23, 2019 (Chinese).
  6. ^ Robert Wimmer-Schweingruber: Chinese moon mission Chang'e 4. In: youtube.com. January 26, 2020, accessed August 30, 2020 .
  7. ↑ 月球 背面 拓荒者 —— 嫦娥 四号 着陆 月球 背面 一 周年. In: clep.org.cn. January 3, 2020, accessed January 3, 2020 (Chinese).
  8. ↑ “天 问 一号” ： 中国 首次 火星 之 旅. In: k.sina.com.cn. July 10, 2020, accessed July 11, 2020 (Chinese).
  9. ↑ 刘 锟: “玉兔 二号” 月球 车 顺利 踏上 月球 背面！ 后续 还将 完成 哪些 使命？ In: jfdaily.com. January 4, 2019, accessed May 7, 2019 (Chinese).
  10. ↑ 嫦娥 四号 着陆 器 和 “玉兔 二号” 巡视 器 进入 第七 月夜. In: clep.org.cn. July 9, 2019, accessed July 13, 2019 (Chinese). The lanes on the second photo show the erratic path that Jade Hare 2 took on the moon by the end of the 7th working day (the rover itself has already disappeared from the field of view of the lander camera).
  11. ↑ Li Chunlai, Su Yan et al .: The Moon's farside shallow subsurface structure unveiled by Chang'E-4 Lunar Penetrating Radar. In: advances.sciencemag.org. February 26, 2020, accessed on March 15, 2020 .
  12. ↑ 叶 瑞 优: 国家 天文台 基于 嫦娥 四号 探测 数据 发现 月球 背面 幔 源 物质 初步 证据. In: cas.cn. May 16, 2019, accessed May 20, 2019 (Chinese). The video shows the basic speed of the rover from 00:17.
  13. ↑ 专家 ： 希望 玉兔 二号 至少 工作 一年. In: clep.org.cn. April 1, 2019, accessed May 10, 2019 (Chinese).
  14. ↑ Chang'e 3, 4 (CE 3, 4) / Yutu. Retrieved January 4, 2019 .
  15. ↑ The scientific objectives and payloads of Chang'e -4 mission . In: Planetary and Space Science . tape 162 , November 1, 2018, ISSN  0032-0633 , p. 207–215 , doi : 10.1016 / j.pss.2018.02.011 ( sciencedirect.com [accessed January 4, 2019]).
  16. ↑ Su Yan, Fang Guangyou et al .: Data processing and initial results of Chang'e-3 lunar penetrating radar. In: iopscience.iop.org. September 13, 2014, accessed March 15, 2020 .
  17. ↑ Fang Guangyou et al .: Lunar Penetrating Radar onboard the Chang'e-3 mission. In: iopscience.iop.org. September 29, 2014, accessed March 15, 2020 .
  18. ↑ Lin Honglei, Lin Yangting et al .: In Situ Photometric Experiment of Lunar Regolith With Visible and Near ‐ Infrared Imaging Spectrometer On Board the Yutu ‐ 2 Lunar Rover. In: agupubs.onlinelibrary.wiley.com. February 11, 2020, accessed on May 9, 2020 .
  19. ↑ 林 杨 挺 et al .: 科研 人员 对 玉兔 二号 光谱 的 光照 作 几何 校正. In: spaceflightfans.cn. May 9, 2020, accessed May 9, 2020 (Chinese).
  20. ↑ Sweden joins China's historic mission to land on the far side of the Moon in 2018. Retrieved January 4, 2019 .
  21. ↑ 张 楷 欣: 嫦娥 四号 着陆 器 和 玉兔 二号 月球 车 自主 唤醒 进入 第 18 月 昼. In: chinanews.com. May 17, 2020, accessed May 17, 2020 (Chinese).
  22. ↑ 嫦娥 四号 玉兔 二号 任务 专题. In: spaceflightfans.cn. May 17, 2020, accessed May 17, 2020 (Chinese).
  23. ↑ 李季: 嫦娥 四号 和 玉兔 二号 自主 唤醒 进入 第十 九月 昼 工作 期. In: chinanews.com. June 15, 2020, accessed June 15, 2020 (Chinese).
  24. ↑ “玉兔 二号” 完成 第十 九月 昼 工作 累计 行驶 里程 463.26 米. In: guancha.cn. June 28, 2020, accessed June 28, 2020 (Chinese). The rover needs a place for the night where it can easily turn so that the solar module on the left in the direction of travel faces east so that it can use the morning sun to wake up.

Web links

Commons : Yutu 2  - collection of pictures, videos and audio files
Jade rabbit 2 (alternative names of the lemma)
Jade Rabbit 2; 玉兔 二号 , yùtù èr hào , Jade Rabbit 2, Yutu-2, Yutu 2, 玉兔 二号 月球 车 ; Chang'e-4 rover; Jade Rabbit 2