Yutu (rover)

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Yutu
玉兔
Yutu.jpg
Yutu rover on the lunar surface, imaged by the Chang'e 3 lander.
Mission typeLunar rover
OperatorCNSA
Mission duration3 months (planned)[1]
2 months and 18 days elapsed
Spacecraft properties
ManufacturerSASEI and BISSE
Landing mass140 kg (310 lb)[2]
Dimensions1.5 m (4.9 ft)
Start of mission
Launch date1 December 2013, 17:30 (2013-12-01UTC17:30Z) UTC[3]
RocketLong March 3B Y-23
Launch siteXichang LC-2
Deployed fromChang'e 3
Lunar rover
Landing date14 December 2013, 13:12 UTC[4]
Landing siteMare Imbrium
44°07′N 19°31′W / 44.12°N 19.51°W / 44.12; -19.51[5]

Chinese Lunar Exploration Program
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Yutu
玉兔
Yutu.jpg
Yutu rover on the lunar surface, imaged by the Chang'e 3 lander.
Mission typeLunar rover
OperatorCNSA
Mission duration3 months (planned)[1]
2 months and 18 days elapsed
Spacecraft properties
ManufacturerSASEI and BISSE
Landing mass140 kg (310 lb)[2]
Dimensions1.5 m (4.9 ft)
Start of mission
Launch date1 December 2013, 17:30 (2013-12-01UTC17:30Z) UTC[3]
RocketLong March 3B Y-23
Launch siteXichang LC-2
Deployed fromChang'e 3
Lunar rover
Landing date14 December 2013, 13:12 UTC[4]
Landing siteMare Imbrium
44°07′N 19°31′W / 44.12°N 19.51°W / 44.12; -19.51[5]

Chinese Lunar Exploration Program
← Chang'e 2Chang'e 4
The planned landing site was Sinus Iridum, a lava-filled crater 249 km (155 mi) in diameter. The actual landing took place on Mare Imbrium.
LRO image of the landing site, which is close to the transition between light and dark maria
LRO close-up image taken on 25 December 2013. The lander (large arrow) and rover (small arrow) can be seen.

Yutu (Chinese: 玉兔; pinyin: Yùtù; literally "Jade Rabbit") is an unmanned lunar rover that forms part of the Chinese Chang'e 3 mission to the Moon. It was launched at 17:30 UTC on 1 December 2013, and reached the Moon's surface on 14 December 2013.[6] The mission marks the first soft landing on the Moon since 1976 and the first rover to operate there since the Soviet Lunokhod 2 ceased operations on 11 May 1973.[7]

History[edit]

The Yutu lunar rover was developed by Shanghai Aerospace System Engineering Institute (SASEI) and Beijing Institute of Spacecraft System Engineering (BISSE). The development of the six-wheeled rover began in 2002 and was completed in May 2010.[8][9][10] It was designed to deploy from the lander and explore the lunar surface independently. The rover's name was selected in an online poll, and is a reference to the pet rabbit of Chang'e, the goddess of the Moon in Chinese mythology.[10]

Objectives[edit]

The official mission objective is to achieve China's first soft-landing and roving exploration on the Moon, as well as to demonstrate and develop key technologies for future missions.[11]

The scientific objectives of Chang'e-3 mainly include lunar surface topography and geology survey, lunar surface material composition and resource survey, Sun-Earth-Moon space environment detection and lunar-based astronomical observation.[11] Chang'e 3 will attempt to perform the first direct measurement of the structure and depth of the lunar soil down to a depth of 30 m (98 ft), and investigate the lunar crust structure down to several hundred meters deep.[12]

The Chinese Lunar Exploration Program has been divided into three main operational phases, which are:[11]

Specifications[edit]

Unlike NASA and ESA, the China National Space Administration reveals little about its missions to the public, so detailed information about Chang'e 3 is limited. Aspects of Yutu's design and several of its experiments may have been based on NASA's Mars Exploration Rovers.[13][14] Its wheel design is believed to have been considerably influenced by what was used on the Russian Lunokhod 1 rover.[14]

The Yutu rover has a mass of 140 kg (310 lb), with a payload capacity of 20 kg (44 lb).[1][2][15] It is smaller than the Mars Exploration Rovers, Spirit and Opportunity, and carries similar instruments: panoramic cameras, an infrared spectrometer and an alpha particle X-ray spectrometer (APXS).[7][16] Yutu is also equipped with a robotic arm to position its APXS near a target sample. In addition, the rover can transmit video in real time, and has automatic sensors to prevent it from colliding with other objects.

Yutu was designed to explore an area of 3 square kilometres (1.2 sq mi) during its 3-month mission, with a maximum travelling distance of 10 km (6.2 mi). Energy is provided by two solar panels, allowing the rover to operate through lunar days. During the 14-day lunar nights the rover will go into sleep mode,[17] during which heating is provided by radioisotope heater units (RHU) and two-phase fluid loops.[18]

Scientific payload[edit]

The Yutu rover carries a ground-penetrating radar and spectrometers to inspect the composition of the soil and the structure of the lunar crust beneath it.

Ground-penetrating radar (GPR)[edit]

The rover carries a ground-penetrating radar (GPR) on its underside, allowing for the first direct measurement of the structure and depth of the lunar soil down to a depth of 30 m (98 ft), and investigation of the lunar crust structure down to several hundred meters deep.[12]

Spectrometers[edit]

The rover carries an alpha particle X-ray spectrometer[19] and an infrared spectrometer, intended to analyze the chemical element composition of lunar samples.

Stereo cameras[edit]

There are two panoramic cameras and two navigation cameras on the rover's mast, which stands ~1.5 m (4.9 ft) above the lunar surface, as well as two hazard avoidance cameras installed on the lower front portion of the rover.[20] Each camera pair may be used to capture stereoscopic images,[21] or for range imaging by triangulation.

Landing site[edit]

Chang'e 3 landed on 14 December 2013 and deployed the Yutu rover 7 hours 24 minutes later.[22]

The planned landing site was announced to be Sinus Iridum.[23] However, the lander descended on Mare Imbrium, about 40 km (25 mi) south of the 6 km (3.7 mi) diameter Laplace F crater,[24][25] at 44.1214°N, 19.5116°W (2640 m elevation)[26]

Activities[edit]

First lunar day[edit]

The rover was successfully deployed from the lander, and made contact with the lunar surface on 14 December, 20:35 UTC.[27] On 17 December it was announced that all of the scientific tools apart from the spectrometers had been successfully activated, and that both the lander and rover were "functioning as hoped, despite the unexpectedly rigorous conditions of the lunar environment".[2] However, from 16 December to 20 December the rover did not move, having been partially powered down. Direct solar radiation had raised the temperature on the sunlit side of the rover to over 100°C, while the shaded side simultaneously fell below zero.[28]

By 22 December Yutu had completed its first tasks; to photograph the lander from several different angles, following a roughly semi-circular route from due-north of the lander to due-south, while at the same time being photographed and filmed by the lander. A number of these images have been released, including a stereoview of the lander and videos of the rover in motion. The lander and rover then commenced their respective science missions.[29][30][21]

In addition to successfully deploying its robotic arm, Yutu completed checks on 23 December to ensure that it was prepared for the coming lunar night, and moved about 40 metres south of the lander.[31] The lander was also tested the following day. The lander entered sleep mode first, at around 11am China Standard Time on 25 December, followed by the rover at 05:23 on 26 December. Both will have to withstand the extreme cold of the two week long lunar nights.[32][17]

Second lunar day[edit]

On 11 January 2014, after the two-week lunar night was over, both the rover and lander were taken out of sleep mode.[33] On 16 January, the rover completed its first examination of the lunar soil.[34] On 25 January 2014, near the end of the second lunar day, China's state media announced the rover had undergone a "mechanical control abnormality" and cited the problem was caused by the "complicated lunar surface environment".[35] The Planetary Society suggested that the rover was not responding properly to commands from Earth, so it "could not prepare for the oncoming night properly."[36][37][38][39]

Third lunar day[edit]

Command Control was expecting the rover to contact Earth on 12 February 2014 had it endured its second lunar night. Since it did not transmit any signals, the rover was officially declared permanently inoperative.[40] However, one day later, on 13 February, the rover reestablished communication with Command Control.[41][42][43] China's lunar program spokesman Pei Zhaoyu declared that although Yutu is able to communicate, "it still suffers a mechanical control abnormality."[44]

Popular culture[edit]

The rover has a dedicated, although not official, Weibo account (Jade Rabbit Lunar Rover) with over 300,000 followers, posting sometimes humorous updates regarding its status. Twitter has also an unofficial account dedicated to the rover, @JadeRabbitRover with about 150 followers.

See also[edit]

References[edit]

  1. ^ a b "Chang’e-3: China To Launch First Moon Rover In 2013". Asian Scientist. 7 March 2012. Retrieved 5 April 2012. 
  2. ^ a b c "Most Chang'e-3 science tools activated". Retrieved 19 December 2013. 
  3. ^ "China Starts Manufacturing Third Lunar Probe". English.cri.cn. Retrieved 2013-12-02. 
  4. ^ China Will Kick Off December By Launching A Probe To The Moon - Forbes
  5. ^ Chang'e-3 soft-lands on moon
  6. ^ "China lands Jade Rabbit robot rover on Moon". BBC. 14 December 2013. 
  7. ^ a b Molnár, László (24 May 2013). "Chang'e-3 revealed – and its massive!". Pull Space Technologies. Retrieved 2013-12-09. 
  8. ^ "登月车构造原理". 新华网. 24 April 2008. Retrieved 24 April 2008. 
  9. ^ "中国首辆登月车工程样机". 新华网. 24 April 2008. Retrieved 24 April 2008. 
  10. ^ a b Ramzy, Austin (26 November 2013). "China to Send 'Jade Rabbit' Rover to the Moon". The New York Times. Retrieved 2 December 2013. 
  11. ^ a b c SUN ZeZhou; JIA Yang, and ZHANG He (November 2013). "Technological advancements and promotion roles of Chang’e-3 lunar probe mission". Science China (PDF) 56 (11): 2702–2708. doi: 10.1007/s11431-013-5377-0. 
  12. ^ a b "欧阳自远:嫦娥三号明年发射将实现着陆器与月球车联合探测". Xinhua. 14 June 2012. Retrieved 23 July 2013. 
  13. ^ Covault, Craig (November 2013). "China's bold lunar plan". Aerospace America (American Institute of Aeronautics and Astronautics). Retrieved 9 February 2014. 
  14. ^ a b Chen, Stephen (25 October 2013). "Chinese lunar rover looks too much like Nasa's Opportunity, say scientists". South China Morning Post. Retrieved 9 February 2014. 
  15. ^ "China considering manned lunar landing in 2025–2030". Xinhua. 24 May 2009. Retrieved 1 October 2010. 
  16. ^ ""嫦娥三号"发射成功 将于5天后到达月球". Netease. 2 December 2013. paragraph “月兔”将巡天观地测月. 
  17. ^ a b "Moon rover Yutu sleeps as night comes". Xinhua. 26 December 2013. Retrieved 27 December 2013. 
  18. ^ SUN ZeZhou; JIA Yang, and ZHANG He (November 2013). "Technological advancements and promotion roles of Chang’e-3 lunar probe mission" (PDF). Science China 56 (11): 2702–2708. doi: 10.1007/s11431-013-5377-0. Retrieved 2013-12-09. 
  19. ^ ""嫦娥三号"发射成功 将于5天后到达月球". Netease. 2 December 2013. paragraph “月兔”将巡天观地测月. 
  20. ^ "Chang'e 3". SPACEFLIGHT101. Retrieved 2 December 2013. 
  21. ^ a b "Chang'e 3 update with lots of pictures: Yutu begins lunar journey". 
  22. ^ O'Neil, Ian (14 December 2013). "China's Rover Rolls! Yutu Begins Moon Mission". Discovery News (CCTV). Retrieved 2013-12-15. 
  23. ^ "Chang'e 3 Diary". Zarya.info. 6 December 2013. Retrieved 2013-12-09. 
  24. ^ "Chang'e 3 landing coordinates". China News (CN). 14 December 2013. Retrieved 2013-12-15. 
  25. ^ Emily Lakdawalla; Phil Stooke (December 2013). "Chang'e 3 has successfully landed on the Moon!". The Planetary Society. Retrieved 2013-12-15. 
  26. ^ "NASA Images of Chang'e 3 Landing Site". 
  27. ^ http://www.youtube.com/watch?v=0S7E572zTlc Live* Yutu Rover "Jade Rabbit" separates from lander on the Moon
  28. ^ "China's Yutu "naps", awakens and explores". Retrieved 2013-12-21. 
  29. ^ "Lander and rover ready to perform exploration tasks". 
  30. ^ ""玉兔" 月球车机械臂投放测试成功". 
  31. ^ Stephen Clark (27 December 2013). "Chinese rover hibernating to survive frigid lunar night". Spaceflight Now. Retrieved 27 December 2013. 
  32. ^ "China's moon rover flexes muscles". 
  33. ^ Boyle, Alan (12 January 2014). "Chinese moon lander and rover wake up after weeks of sleep". Xinhua. (NBC News). Retrieved 2014-01-14. 
  34. ^ "China's Jade Rabbit rover explores Moon soil". BBC. 16 January 2014. Retrieved 17 January 2014. 
  35. ^ China's first moon rover has experienced a "mechanical control abnormality" - Australian Broadcasting Corporation - Retrieved 25 January 2014.
  36. ^ Lakdawalla, Emily (25 January 2014). "Bad news for Yutu rover". Planetary Society. Retrieved 2014-01-29. 
  37. ^ China's imperiled Jade Rabbit moon rover: 'Goodnight, humanity'
  38. ^ Beijing, we have a problem: China's first lunar rover, Jade Rabbit, signs off
  39. ^ China Moon rover Jade Rabbit in trouble
  40. ^ "Jade Rabbit rover 'declared dead'". BBC News. 12 February 2014. Retrieved 2014-02-12. 
  41. ^ "China's Jade Rabbit lunar rover 'could be saved'". BBC. 13 February 2014 1:16 ET. Retrieved 13 February 2014. 
  42. ^ Collins, Katie (13 February 2014 7:00 Pacific). "It's alive! Welcome back, Jade Rabbit". Wired.co.uk. Retrieved 13 February 2014. 
  43. ^ Possible hope for Yutu: "Situation is getting better," but no details [UPDATED Posted by Emily Lakdawalla]
  44. ^ McKirdy, Euan (13 February 2014). "Down but not out: Jade Rabbit comes back from the dead". CNN. Retrieved 2014-02-13. 

External links[edit]