View source for Engineering:Yutu (rover)

{{short description|Chinese lunar rover}}
{{italic title}}
{{Infobox spaceflight
| name                  = ''Yutu''<br />{{nobold|玉兔}}
| image                 = Yutu rover.jpg
| image_caption         = ''Yutu'' rover on lunar surface
| mission_type          = [[Astronomy:Lunar rover|Lunar rover]]
| operator              = [[Organization:China National Space Administration|CNSA]]
| COSPAR_ID             =
| SATCAT                =
| mission_duration      = 3&nbsp;months (planned)<ref name="march 12">{{cite news | first=Srinivas | last=Laxman | title=Chang'e-3: China To Launch First Moon Rover In 2013 | url=http://www.asianscientist.com/topnews/chang-e-3-china-first-moon-rover-launch-in-2013/ | work=Asian Scientist | date=7 March 2012 }}</ref><br /> Actual: {{age in days|2013|12|01|2016|7|31}}&nbsp;days <br /> Immobile since 25 January 2014, 42 days after landing.
| spacecraft_bus        =
| manufacturer          = SASEI and BISSE
| dry_mass              =
| launch_mass           =
| landing_mass          = {{convert|140|kg|lb|abbr=on}}<ref name="Science tools" />
| dimensions            = {{convert|1.5|m|ft|abbr=on}}
| power                 =• [[Physics:Solar panel|Solar panel]]s for electricity<br />• Radioisotope heater units for heating
| launch_date           = {{start-date|1 December 2013, 17:30|timezone=yes}}&nbsp;UTC<ref name="CRI">{{cite web | url=http://english.cri.cn/6909/2012/03/13/53s686639.htm | archive-url=https://web.archive.org/web/20131021091125/http://english.cri.cn/6909/2012/03/13/53s686639.htm | url-status=dead | archive-date=21 October 2013 | title=China Starts Manufacturing Third Lunar Probe | author=Zhang | publisher=CRI | date=13 March 2012 }}</ref>
| launch_rocket         = [[Engineering:Long March 3B|Long March 3B]] Y-23
| launch_site           = Xichang LC-2
| deployment_from       = [[Astronomy:Chang'e 3|Chang'e 3]] <!-- Note: Chang'e 3 is the name the mission, not the lander. -->
| deployment_date       =
| launch_contractor     =

| last_contact          = Mid-2016
| declared              = 3 August 2016
| interplanetary        =
{{Infobox spaceflight/IP
   |type                = rover
   |object              = Lunar
   |component           =
   |arrival_date        = 14 December 2013, 13:12 UTC<ref name="Forbes">{{cite news | url=https://www.forbes.com/sites/alexknapp/2013/11/30/china-will-kick-off-december-by-launching-a-probe-to-the-moon/ | title=China Will Kick Off December By Launching A Probe To The Moon | last=Knapp | first=Alex | work=Forbes | date=30 November 2013 | url-status=live | archive-date=14 December 2013 | archive-url=https://web.archive.org/web/20131214101329/http://www.forbes.com/sites/alexknapp/2013/11/30/china-will-kick-off-december-by-launching-a-probe-to-the-moon/ }}</ref>
   |location            = [[Astronomy:Mare Imbrium|Mare Imbrium]]<br />{{Lunar coords and quad cat|44.12|N|19.51|W}}<ref name="Xinhua">{{cite news | url=http://news.xinhuanet.com/english/photo/2013-12/14/c_132968229_10.htm | title=Chang'e-3 soft-lands on moon | work=xinhuanet | date=14 December 2013 | url-status=dead | archive-url=https://web.archive.org/web/20131217071456/http://news.xinhuanet.com/english/photo/2013-12/14/c_132968229_10.htm | archive-date=17 December 2013 | df=dmy-all }}</ref>
   |distance            = {{convert|114.8|m|ft|abbr=on}}<ref>{{cite news|url=https://global.chinadaily.com.cn/a/201902/13/WS5c63d6a7a3106c65c34e924f.html|title=China's Chang'e 4 probe switches back to dormant mode|date=13 February 2019|work = China Daily}}</ref>
}}
| previous_mission      = 
| next_mission          = ''[[Astronomy:Yutu-2|Yutu-2]]''
| programme             = '''[[Astronomy:Chinese Lunar Exploration Program|Chinese Lunar Exploration Program]] rovers'''
}}

'''''Yutu''''' ({{zh|c=玉兔|p=Yùtù|l=Jade Rabbit}}) was a robotic  [[Astronomy:Lunar rover|lunar rover]] that formed part of the Chinese [[Astronomy:Chang'e 3|Chang'e 3]] mission to the [[Astronomy:Moon|Moon]]. It was launched at 17:30 UTC on 1 December 2013, and reached the Moon's surface on 14 December 2013.<ref name="bbc_25356603">{{cite news | url=https://www.bbc.co.uk/news/science-environment-25356603 | title=China lands Jade Rabbit robot rover on Moon | date=14 December 2013 | publisher=BBC }}</ref> The mission marks the first soft landing on the Moon since 1976 and the first [[Astronomy:Rover (space exploration)|rover]] to operate there since the Soviet [[Astronomy:Lunokhod 2|Lunokhod 2]] ceased operations on 11 May 1973.<ref name="Molnár-May2013">{{cite news | first=László | last=Molnár | title=Chang'e-3 revealed – and its massive! | date=24 May 2013 | url=http://www.pulispace.com/en/media/news/231-change-3-revealed-and-its-massive | work=Pull Space Technologies | access-date=9 December 2013 | archive-date=6 June 2017 | archive-url=https://web.archive.org/web/20170606034406/http://www.pulispace.com/en/media/news/231-change-3-revealed-and-its-massive | url-status=dead }}</ref>

The rover encountered operational difficulties toward the end of the second lunar day<ref name="abnormality">{{cite news | url=http://www.abc.net.au/news/2014-01-25/an-china27s-moon-rover2c-jade-rabbit2c-has-27abnormality27/5218986 | title=China's first moon rover has experienced a "mechanical control abnormality | publisher=Australian Broadcasting Corporation | date=26 January 2014 }}</ref> after surviving and recovering successfully from the first 14-day lunar night.<ref name="back">{{cite news|first=Alan |last=Boyle |title=Chinese moon lander and rover wake up after weeks of sleep |date=12 January 2014 |publisher=NBC News |url=http://www.nbcnews.com/science/chinese-moon-lander-rover-wake-after-weeks-sleep-2D11909188 |url-status=dead |archive-url=https://web.archive.org/web/20140114045936/http://www.nbcnews.com/science/chinese-moon-lander-rover-wake-after-weeks-sleep-2D11909188 |archive-date=14 January 2014 }}</ref> It was unable to move after the end of the second lunar night, though it continued to gather useful information for some months afterward.<ref name="Not dead yet" /> In October 2015, ''Yutu'' set the record for the longest operational period for a rover on the Moon.<ref>{{cite news |url= http://spacenews.com/chinas-immobile-rover-passes-a-purely-figurative-milestone/ |title= China's Immobile Rover Passes a Purely Figurative Milestone |author= Jeff Foust |date= 30 October 2015 |publisher= SpaceNews }}</ref> On 31 July  2016, ''Yutu'' ceased to operate after a total of 31 months, well beyond its original expected lifespan of three months.

In total, while working on the Moon, the rover was able to travel a distance of 114 meters.<ref>[https://web.archive.org/web/20190104134501/http://www.xinhuanet.com/english/2019-01/04/c_137719617.htm China Focus: China's upgraded lunar rover drives on moon's far side]</ref>

In 2018 the follow-on to the ''Yutu'' rover, the ''[[Astronomy:Yutu-2|Yutu-2]]'' rover, launched as part of the [[Astronomy:Chang'e 4|Chang'e 4]] mission.

==History==
[[File:玉兔号月球车（1：1）.jpg|thumb|alt=Full scale mock-up of Yutu rover|Full scale mock-up of ''Yutu'' rover]]
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.<ref name="xinhuanet_20080424a">{{cite web | url=http://news.xinhuanet.com/tech/2008-04/24/xinsrc_332040524080250082374.jpg | archive-url=https://web.archive.org/web/20090227143654/http://news.xinhuanet.com/tech/2008-04/24/xinsrc_332040524080250082374.jpg | url-status=dead | archive-date=27 February 2009 | script-title=zh:登月车构造原理 | language=zh | trans-title=Lunar vehicle structure principle | publisher=新华网 | date=24 April 2008 }}</ref><ref name="xinhuanet_20080424b">{{cite web |url=http://news.xinhuanet.com/tech/2008-04/24/xinsrc_332040524080210976603.jpg |archive-url=https://web.archive.org/web/20090227143656/http://news.xinhuanet.com/tech/2008-04/24/xinsrc_332040524080210976603.jpg |url-status=dead |archive-date=27 February 2009 | script-title=zh:中国首辆登月车工程样机 | language=zh | trans-title=China's first lunar landing vehicle engineering prototype vehicles | publisher=新华网 | date=24 April 2008 }}</ref><ref name="nyt20131202">
{{cite news | first=Austin | last=Ramzy | title=China to Send 'Jade Rabbit' Rover to the Moon | date=26 November 2013 | url=http://sinosphere.blogs.nytimes.com/2013/11/26/china-to-send-jade-rabbit-rover-to-the-moon/?_r=1 | work=The New York Times }}</ref> The rover deployed from the lander and explored the lunar surface independently. The rover's name was selected in an online poll, and is a reference to the [[Unsolved:Moon rabbit|pet rabbit]] of [[Religion:Chang'e|Chang'e]], the goddess of the Moon in Chinese mythology.<ref name="nyt20131202" />

==Objectives==
The official mission objective was 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.<ref name="Science China vol 56">{{cite journal | title=Technological advancements and promotion roles of Chang'e-3 lunar probe mission | journal=Science China | date=November 2013 | last1=SUN | first1=ZeZhou | last2=JIA | first2=Yang | last3=ZHANG | first3=He | volume=56 | issue=11 | pages=2702–2708 | doi=10.1007/s11431-013-5377-0 | bibcode=2013ScChE..56.2702S | s2cid=111801601 | url=http://tech.scichina.com:8082/sciEe/EN/article/downloadArticleFile.do?attachType=PDF&id=512308 | format=PDF | url-status=dead | archive-date=29 March 2014 | archive-url=https://web.archive.org/web/20140329104235/http://tech.scichina.com:8082/sciEe/EN/article/downloadArticleFile.do?attachType=PDF&id=512308 | access-date=25 December 2013 | df=dmy-all }}</ref>

The scientific objectives of Chang'e-3 mainly included lunar surface topography and geological survey, lunar surface material composition and resource survey, Sun-Earth-Moon space environment detection, and lunar-based astronomical observation.<ref name="Science China vol 56" /> Chang'e 3 performed the first direct radar measurement of the structure and depth of the [[Astronomy:Lunar soil|lunar soil]] down to a depth of {{convert|30|m|ft|abbr=on}}, and investigated the [[Astronomy:Internal structure of the Moon|lunar crust structure]] down to several hundred meters deep.<ref name="xinhuanet_2012-06">{{cite news | url=http://news.xinhuanet.com/politics/2012-06/14/c_112217044.htm | archive-url=https://web.archive.org/web/20120617020908/http://news.xinhuanet.com/politics/2012-06/14/c_112217044.htm | url-status=dead | archive-date=17 June 2012 | script-title=zh: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 | language=zh | trans-title=Ouyang: Chang E III launch next year will achieve lander and rover joint probe | publisher=Xinhua | date=14 June 2012 }}</ref>

The [[Astronomy:Chinese Lunar Exploration Program|Chinese Lunar Exploration Program]] was divided into three main operational phases:<ref name="Science China vol 56" />
* Orbiting ([[Astronomy:Chang'e 1|Chang'e 1]] and [[Astronomy:Chang'e 2|Chang'e 2]])
* Landing ([[Astronomy:Chang'e 3|Chang'e 3]] and [[Astronomy:Chang'e 4|Chang'e 4]])
* Sample return ([[Astronomy:Chang'e 5|Chang'e 5]])

== Specifications ==

Unlike [[Organization:NASA|NASA]] and [[Organization:European Space Agency|ESA]], the [[Organization:China National Space Administration|China National Space Administration]] reveals little about its missions to the public, so detailed information about [[Astronomy:Chang'e 3|Chang'e 3]] is limited. Aspects of ''Yutu''{{'s}} design and several of its experiments may have been based on NASA's [[Astronomy:Mars Exploration Rover|Mars Exploration Rover]]s.<ref name="aa_2013">{{cite web | url=http://www.aerospaceamerica.org/Documents/AerospaceAmerica-PDFs-2013/November-2013/Feature_ChinasBoldLunarPlan_AANov2013.pdf | title=China's bold lunar plan | last=Covault | first=Craig | date=November 2013 | publisher=Aerospace America (American Institute of Aeronautics and Astronautics) | url-status=dead | archive-url=https://web.archive.org/web/20160305063850/http://www.aerospaceamerica.org/Documents/AerospaceAmerica-PDFs-2013/November-2013/Feature_ChinasBoldLunarPlan_AANov2013.pdf | archive-date=5 March 2016 | df=dmy-all }}</ref><ref name=SCMP>{{cite web | url=http://www.scmp.com/news/china/article/1339152/chinese-lunar-rover-looks-too-much-nasas-opportunity-say-scientists?page=all | title=Chinese lunar rover looks too much like Nasa's Opportunity, say scientists | last=Chen | first=Stephen | date=25 October 2013 | publisher=South China Morning Post }}</ref> Its wheel design is believed to have been considerably influenced by what was used on the Russian [[Astronomy:Lunokhod 1|Lunokhod 1]] rover.<ref name="SCMP" />

The ''Yutu'' rover has a mass of {{convert|140|kg|lb|abbr=on}}, with a payload capacity of {{convert|20|kg|lb|abbr=on}}.<ref name="march 12" /><ref name="Science tools" /><ref name="xin_200905">{{cite news | url=http://news.xinhuanet.com/english/2009-05/24/content_11425131.htm | archive-url=https://web.archive.org/web/20090531002641/http://news.xinhuanet.com/english/2009-05/24/content_11425131.htm | url-status=dead | archive-date=31 May 2009 | title=China considering manned lunar landing in 2025–2030 | date=24 May 2009 | agency=Xinhua }}</ref> It is smaller than the Mars Exploration Rovers, ''Spirit'' and ''Opportunity'', and  carries similar instruments: panoramic cameras, an infrared spectrometer and an [[Astronomy:Alpha particle X-ray spectrometer|alpha particle X-ray spectrometer]] (APXS).<ref name="Molnár-May2013" /><ref name="news_163">{{cite web | url=http://news.163.com/13/1202/02/9F2BAFI200014AED_all.html | script-title=zh:"嫦娥三号"发射成功 将于5天后到达月球 | language=zh | trans-title=Chang'e III will be successful launch 5 days to reach the moon | publisher=Netease | date=2 December 2013 | at=paragraph "月兔"将巡天观地测月 | access-date=9 December 2013 | archive-url=https://web.archive.org/web/20131213021728/http://news.163.com/13/1202/02/9F2BAFI200014AED_all.html | archive-date=13 December 2013 | url-status=dead }}</ref> ''Yutu'' is also equipped with a robotic arm to position its APXS near a target sample. In addition, the rover could transmit live video, and has automatic sensors to prevent it from colliding with other objects.

''Yutu'' was designed to explore an area of {{convert|3|sqkm}} during its three-month mission, with a maximum travelling distance of {{convert|10|km|mi|abbr=on}}. Energy was provided by two [[Physics:Solar panel|solar panel]]s, allowing the rover to operate through lunar days. During the 14-day lunar nights, the rover went into [[Sleep mode|sleep mode]],<ref name="xi-20131226" /> during which heating was provided by [[Engineering:Radioisotope heater unit|radioisotope heater unit]]s (RHU) using [[Physics:Plutonium-238|plutonium-238]]<ref name="pu238">{{cite web | url=http://www.lpi.usra.edu/sbag/meetings/jan2014/presentations/08_1545_McNutt_Pu238_SBAG.pdf | title=Radioisotope Power Systems: Pu-238 and ASRG status and the way forward | first=Ralph L. Jr. | last=McNutt | publisher=[[Organization:Johns Hopkins University|Johns Hopkins University]] | date=January 2014 | url-status=live | archive-date=28 March 2014 | archive-url=https://web.archive.org/web/20140328214729/http://www.lpi.usra.edu/sbag/meetings/jan2014/presentations/08_1545_McNutt_Pu238_SBAG.pdf }}</ref> and two-phase fluid loops.<ref name="Science China vol 56" />

==Scientific payload==
The ''Yutu'' rover carried a [[Earth:Ground-penetrating radar|ground-penetrating radar]] and spectrometers to inspect the composition of the soil and the structure of the [[Astronomy:Internal structure of the Moon|lunar crust]] beneath it.

===Ground-penetrating radar (GPR)===
The rover carried a [[Earth:Ground-penetrating radar|ground-penetrating radar]] (GPR) on its underside, allowing for the first direct measurement of the structure and depth of the [[Astronomy:Lunar soil|lunar soil]] down to a depth of {{convert|30|m|ft|abbr=on}}, and investigation of the [[Astronomy:Internal structure of the Moon|lunar crust structure]] down to several hundred metres deep.<ref name="xinhuanet_2012-06" />

===Spectrometers===
The rover carried an [[Astronomy:Alpha particle X-ray spectrometer|alpha particle X-ray spectrometer]] (APXS)<ref name="news_163" /> and an infrared spectrometer, intended to analyze the [[Chemistry:Chemical element|chemical element]] composition of lunar samples. The APXS was the only payload on the robotic arm.<ref name="APXS">{{cite conference |last1=Peng |first1=W.X. |last2=Wang |first2=H.Y. |title=Active Particle-induced X-ray Spectrometer for CHANG'E-3 YuTu Rover Mission and its first results |url=http://www.hou.usra.edu/meetings/lpsc2014/pdf/1699.pdf |conference=45th Lunar and Planetary Science Conference (2014) |date=2014 }}</ref>

===Stereo cameras===
There were two panoramic cameras and two navigation cameras on the rover's mast, which stands ~{{convert|1.5|m|ft|abbr=on}} above the lunar surface, as well as two hazard avoidance cameras installed on the lower front portion of the rover.<ref name="spaceflight2">{{cite web | url=http://www.spaceflight101.com/change-3.html | title=Chang'e 3 | publisher=SPACEFLIGHT101 | access-date=2 December 2013}}</ref> Each [[Stereo camera|camera pair]] was used to capture [[Stereoscopy|stereoscopic]] images,<ref name="planetary.org_2013-12-23" /> or for [[Range imaging|range imaging]] by [[Stereo cameras|triangulation]].

==Landing site==
[[File:Chang'e-3 lunar landing site.jpg|thumb|280px|The planned landing site was Sinus Iridum, a lava-filled crater {{convert|249|km|mi|abbr=on}} in diameter. The actual landing took place on Mare Imbrium.]]
[[File:Sinus Iridum, Chang'e 3 & Lunokhod 1 landing sites.png|thumb|280px|[[Astronomy:Lunar Reconnaissance Orbiter|LRO]] image of the landing site, which is close to the transition between light and dark maria]]
[[File:Chang'e 3 landing site.png|thumb|280px|[[Astronomy:Lunar Reconnaissance Orbiter|LRO]] close-up image taken on 25 December 2013. The lander (large arrow) and rover (small arrow) can be seen.]]

Chang'e 3 landed on 14 December 2013 and deployed the ''Yutu'' rover 7 hours 24 minutes later.<ref name="discovery_131214">{{cite news | first=Ian | last=O'Neil | title=China's Rover Rolls! Yutu Begins Moon Mission | date=14 December 2013 | publisher=CCTV | url=http://news.discovery.com/space/chinas-rover-rolls-yutu-begins-moon-mission-131214.htm | work=Discovery News | access-date=15 December 2013 | archive-date=3 March 2016 | archive-url=https://web.archive.org/web/20160303185633/http://news.discovery.com/space/chinas-rover-rolls-yutu-begins-moon-mission-131214.htm | url-status=dead }}</ref>

The planned landing site was announced to be [[Astronomy:Sinus Iridum|Sinus Iridum]].<ref name="Zarya Diary">{{cite web | url=http://www.zarya.info/Diaries/China/ChangE/ChangE3Diary.php#end | title=Chang'e 3 Diary | date=6 December 2013 | work=Zarya | access-date=9 December 2013 | archive-date=29 November 2014 | archive-url=https://web.archive.org/web/20141129020252/http://www.zarya.info/Diaries/China/ChangE/ChangE3Diary.php#end | url-status=dead }}</ref> However, the lander descended on [[Astronomy:Mare Imbrium|Mare Imbrium]], about {{convert|40|km|mi|abbr=on}} south of the {{convert|6|km|mi|abbr=on}} diameter crater ''Laplace F'',<ref name="image">{{cite web | url=http://planetary.s3.amazonaws.com/assets/images/3-moon/20131214_change_landing_location.jpg | title=Chang'e 3 landing coordinates | date=14 December 2013 | work=China News }}</ref><ref name="Landing in Mare Imbrium">{{cite news | first1=Emily | last1=Lakdawalla | first2=Phil | last2=Stooke |  title=Chang'e 3 has successfully landed on the Moon! | date=December 2013 | url=http://www.planetary.org/blogs/emily-lakdawalla/2013/12140619-change-3-has-successfully-landed.html | work=The Planetary Society }}</ref> at 44.1214°N, 19.5116°W (2640&nbsp;m elevation)<ref name="nasa_images">{{cite web | title=NASA Images of Chang'e 3 Landing Site | url=http://www.nasa.gov/content/nasa-images-of-change-3-landing-site/ | publisher=NASA | date=30 December 2013 }}</ref>

==Operations==
[[File:Chang'e 3 - rocks near Ziwei crater.jpg|thumb|280px|alt=Boulders near Ziwei crater. Image captured by Yutu rover|Boulders near Ziwei crater photographed by the ''Yutu'' rover]]

===First lunar day===
The rover was successfully deployed from the lander and made contact with the lunar surface on 20:35 UTC, 14 December 2013.<ref name="yt.0S7E572zTlc">{{cite web| url=https://www.youtube.com/watch?v=0S7E572zTlc | title=Yutu Rover "Jade Rabbit" separates from lander on the Moon | publisher=Youtube | date=14 December 2013 }}</ref> On 17 December 2013, it was announced that all of the scientific instruments except the [[Physics:Spectrometer|spectrometer]]s were successfully activated, with both the lander and rover "functioning as hoped, despite the unexpectedly rigorous conditions of the lunar environment".<ref name="Science tools">{{cite web | url=http://news.xinhuanet.com/english/china/2013-12/18/c_132977079.htm | title=Most Chang'e-3 science tools activated | work=xinhuanet | date=18 December 2013 | url-status=dead | archive-url=https://web.archive.org/web/20131218121731/http://news.xinhuanet.com/english/china/2013-12/18/c_132977079.htm | archive-date=18 December 2013 | df=dmy-all }}</ref> From 16 December 2013 to 20 December 2013, the rover remained immobile as its systems were partially powered down. Direct solar radiation raised the temperature on the exposed side of the rover to over 100&nbsp;°C, while the shaded side simultaneously fell below 0&nbsp;°C.<ref name="Yutu naps">{{cite web | url=http://news.xinhuanet.com/english/china/2013-12/20/c_125893854.htm | title=China's Yutu "naps", awakens and explores | work=xinhuanet | date=20 December 2013 | url-status=dead | archive-url=https://web.archive.org/web/20131224053039/http://news.xinhuanet.com/english/china/2013-12/20/c_125893854.htm | archive-date=24 December 2013 | df=dmy-all }}</ref>

By 22 December 2013, ''Yutu'' had completed its initial science mission: to photograph the lander from several different angles, following a roughly semi-circular route from north to south of the lander, while also being photographed and filmed at the same time by the lander. A number of these images have been released, including a [[Stereoscopy|stereoscopic]] view of the lander and videos of the rover in motion. The lander and rover then commenced their respective science missions.<ref name="planetary.org_2013-12-23">{{cite web | title=Chang'e 3 update with lots of pictures: Yutu begins lunar journey | url=http://www.planetary.org/blogs/emily-lakdawalla/2013/12231242-change3-update.html | last=Lakdawalla | first=Emily |  publisher=The Planetary Society | date=23 December 2013 | url-status=live | archive-date=26 December 2013 | archive-url=https://web.archive.org/web/20131226031855/http://www.planetary.org/blogs/emily-lakdawalla/2013/12231242-change3-update.html }}</ref><ref name="english.cntv.cn_2013-12-22">{{cite web | title=Lander and rover ready to perform exploration tasks | url=http://english.cntv.cn/program/china24/20131222/103912.shtml | publisher=CNTV | date=22 December 2013 | access-date=24 December 2013 | archive-url=https://web.archive.org/web/20131225093205/http://english.cntv.cn/program/china24/20131222/103912.shtml | archive-date=25 December 2013 | url-status=dead | df=dmy-all }}</ref><ref name="chinanews.com_2013-12-23">{{cite web | script-title=zh:"玉兔" 月球车机械臂投放测试成功 | language=zh | trans-title="Rabbit" robotic rover launch test is successful | url=http://www.chinanews.com/gn/2013/12-23/5653502.shtml | work=China News | date=23 December 2013 }}</ref>

In addition to successfully deploying its robotic arm, ''Yutu'' completed diagnostic checks on 23 December 2013 to ensure that it was prepared for the upcoming lunar night, and moved about 40 metres south of the lander.<ref name="sfn-20131227">{{cite news | url=http://spaceflightnow.com/china/change3/131227hibernation/ | title=Chinese rover hibernating to survive frigid lunar night | first=Stephen | last=Clark | publisher=Spaceflight Now | date=27 December 2013 }}</ref> The lander also commenced diagnostics the following day. The lander first entered [[Sleep mode|a low-power state]] at around 11:00 am, UTC+8 on 25 December 2013, later executed by the rover at 5:23 am on 26 December 2013 to conserve power as no sunlight will be received by the lander and rover's solar panels for 14 consecutive days. Both had to withstand the extreme cold of the two-week-long lunar nights.<ref name="xi-20131226">{{cite news | url=http://news.xinhuanet.com/english/sci/2013-12/26/c_132998160.htm | title=Moon rover Yutu sleeps as night comes | publisher=Xinhua | date=26 December 2013 | url-status=dead | archive-url=https://web.archive.org/web/20131231230630/http://news.xinhuanet.com/english/sci/2013-12/26/c_132998160.htm | archive-date=31 December 2013 | df=dmy-all }}</ref><ref name="xinhuanet_2013-12-23">{{cite news | title=China's moon rover flexes muscles | url=http://news.xinhuanet.com/english/china/2013-12/23/c_132990311.htm | publisher=Xinhua | date=23 December 2013 | url-status=dead | archive-url=https://web.archive.org/web/20131231215717/http://news.xinhuanet.com/english/china/2013-12/23/c_132990311.htm | archive-date=31 December 2013 | df=dmy-all }}</ref>

===Second lunar day===
On 11 January 2014, following the lunar night, the rover exited [[Sleep mode|sleep mode]]<ref name="back" /> and completed its first [[Astronomy:Lunar soil|lunar soil]] inspection on 16 January 2014.<ref name="bbc_25763168">{{cite news | url=https://www.bbc.co.uk/news/science-environment-25763168 | title=China's Jade Rabbit rover explores Moon soil | publisher=BBC | date=16 January 2014 | work=BBC News }}</ref> On 25 January 2014, near the end of the second lunar day, China's state media announced that the rover had undergone a "mechanical control abnormality", as caused by the "complicated lunar surface environment".<ref name="abnormality" /> [[Organization:The Planetary Society|The Planetary Society]] reported that the rover was not responding to commands from Earth correctly, rendering it unable to "prepare for the oncoming night properly."<ref name="control issue">{{cite news | first=Emily | last=Lakdawalla |  title=Bad news for Yutu rover | date=25 January 2014 | url=http://www.planetary.org/blogs/emily-lakdawalla/2014/01251527-bad-news-for-yutu-rover.html | work=Planetary Society }}</ref><ref name="cnn_jade">{{cite news | url=http://edition.cnn.com/2014/01/27/world/asia/china-jade-rabbit-moon-rover-goodnight/ | title=China's imperiled Jade Rabbit moon rover: 'Goodnight, humanity' | last=Wilfred | first=Chan | publisher=CNN | date=28 January 2014 | url-status=live | archive-date=22 February 2014 | archive-url=https://web.archive.org/web/20140222065921/http://edition.cnn.com/2014/01/27/world/asia/china-jade-rabbit-moon-rover-goodnight/ }}</ref><ref name="guardian_2014jan27">{{cite news | url=https://www.theguardian.com/science/2014/jan/27/china-lunar-rover-jade-rabbit-breakdown-moon | title=Beijing, we have a problem: China's first lunar rover, Jade Rabbit, signs off | last=Perraudin | first=Frances | work=The Guardian | date=27 January 2014 }}</ref><ref name="driving unit">{{cite news | url=https://www.bbc.co.uk/news/world-asia-china-25908527 | title=China Moon rover Jade Rabbit in trouble | last=Shukman | first=David | publisher=BBC | date=27 January 2014 | work=BBC News }}</ref> It later became evident that the rover suffered a control circuit malfunction in its driving unit, which prevented it from entering normal dormancy and folding its mast and solar panels.<ref name="Xinhua 3March">{{cite news | author=Staff | title=China Exclusive: Control circuit malfunction troubles China's Yutu | date=3 March 2014 | url=http://news.xinhuanet.com/english/china/2014-03/01/c_133152096.htm | work=Xinhua | url-status=dead | archive-url=https://web.archive.org/web/20140309013421/http://news.xinhuanet.com/english/china/2014-03/01/c_133152096.htm | archive-date=9 March 2014 | df=dmy-all }}</ref><ref name="planetary_update">{{cite news | first=Emily | last=Lakdawalla | author-link = Emily Lakdawalla | title=Brief Yutu update: Slightly more detail on what's keeping rover from roving | date=3 March 2014 | url=http://www.planetary.org/blogs/emily-lakdawalla/2014/03030956-brief-yutu-update.html | work=The Planetary Society }}</ref>

===Third lunar day===
On 12 February 2014, Command Control listened for all transmissions from ''Yutu'' after enduring its second lunar night. Failure of communication attempts caused it to be declared permanently inoperative.<ref name="Rover Inoperative">{{cite news | title=Jade Rabbit rover 'declared dead' | date=12 February 2014 | url=https://www.bbc.co.uk/news/science-environment-26153520 | work=BBC News }}</ref> On 13 February, it unexpectedly re-established communication with Command Control.<ref name="roverworking">{{cite news | title=China's Jade Rabbit lunar rover 'could be saved' | url=https://www.bbc.co.uk/news/science-environment-26153520 | work=BBC | date=13 February 2014 }}</ref><ref name="welcomeback">{{cite magazine | last=Collins | first=Katie | title=It's alive! Welcome back, Jade Rabbit | url=https://www.wired.co.uk/news/archive/2014-02/13/jade-rabbit-lives | magazine=Wired | date=13 February 2014 | url-status=dead | archive-url=https://web.archive.org/web/20160305015919/http://www.wired.co.uk/news/archive/2014-02/13/jade-rabbit-lives | archive-date=5 March 2016 | df=dmy-all }}</ref><ref name="planetary_yutu">{{cite web | url=http://www.planetary.org/blogs/emily-lakdawalla/2014/possible-hope-for-yutu.html | title=Possible hope for Yutu: "Situation is getting better," but no details [UPDATED] | first=Emily | last=Lakdawalla |  publisher=The Planetary Society | date=12 February 2014 }}</ref> China's lunar program spokesman Pei Zhaoyu declared that although ''Yutu'' was able to communicate, "it still suffers a mechanical control abnormality," rendering it immobile.<ref name="Not dead yet">{{cite news | first=Euan | last=McKirdy | title=Down but not out: Jade Rabbit comes back from the dead | date=13 February 2014 | url=http://www.cnn.com/2014/02/12/world/asia/jade-rabbit-resurrection/index.html?hpt=wo_c2 | work=CNN }}</ref>

The rover entered its third hibernation period on 22 February 2014 and continued to remain immobile, while serious technical difficulties persisted, further hampering science operations.<ref name="kremer">{{cite news | first=Ken | last=Kremer | title=Yutu Moon Rover Starts 3rd Night Time Hibernation But Technical Problems Persist | date=23 February 2014 | url=http://www.universetoday.com/109671/yutu-moon-rover-starts-3rd-night-time-hibernation-but-technical-problems-persist/ | work=Universe Today }}</ref> Chinese space scientists eventually ascertained that the control circuit had failed, and this prevented ''Yutu'' from entering normal dormancy as planned,<ref name="driving unit" /><ref name="Xinhua 3March" /> but stated that the GPR, panoramic and infrared imaging equipment were still functioning normally.<ref name="kremer" /><ref name="xi.133136885">{{cite news | first=Wang | last=Cong | title=China Focus: Uneasy rest begins for China's troubled Yutu rover | date=23 February 2014 | url=http://news.xinhuanet.com/english/china/2014-02/23/c_133136885.htm | work=Xinhua News | url-status=dead | archive-url=https://web.archive.org/web/20140224083024/http://news.xinhuanet.com/english/china/2014-02/23/c_133136885.htm | archive-date=24 February 2014 | df=dmy-all }}</ref>

===14th lunar day===
While amateur observers were unable to detect transmissions from the lander, Chinese officials reported that the craft was still operating its UV Camera and Telescope as it entered its 14th lunar night on 14 January 2015.<ref>[http://www.spaceflight101.com/change-3-mission-updates.html China's Chang'e 3 Lander in good Shape as 14th Lunar Night sets in] spaceflight101.com</ref><ref name=phys-pano>{{cite news |last=Howell |first=Elizabeth |url=http://phys.org/news/2014-09-china-yutu-rover-alive-lunar.html |title=China's Yutu rover is still alive, reports say, as lunar panorama released |work=Universe Today |publisher=PhysOrg |date=9 September 2014 |access-date=2 October 2014}}</ref> On 18 April 2014, Wang Jianyu, deputy secretary general of the Chinese Society of Space Research stated that the failure was not mechanical, but electrical, and they were looking to bypass it. He also explained, "The temperature on the Moon is considerably lower than our previous estimation", adding that "certain components may be suffering from 'frostbite'".<ref>Chen, Stephen, [http://www.scmp.com/news/china/article/1486425/last-ditch-efforts-salvage-mission-chinas-stricken-jade-rabbit-lunar Last-ditch efforts to salvage mission of China's stricken Jade Rabbit lunar rover], ''South China Morning Post'', 18 April 2014.</ref>

''Yutu's'' solar panel alignment motors failed to respond, causing its solar panels to remain fully deployed as opposed to its planned insulating position to conserve heat as it entered low-power mode, exposing its internal electronics to the Moon's harsh outer environment. As ''Yutu'' progressed through consequent lunar nights, it lost certain capabilities,<ref>{{cite news |url= http://www.spacedaily.com/reports/Chinese_lunar_rover_alive_but_weak_999.html |title= Chinese lunar rover alive but weak |date= 29 May 2014 |author= Xinhua News Agency |publisher= SpaceDaily }}</ref> but successfully exceeded its expected three-month operating life.<ref name="exceeded life">{{cite news | last=Fan | first=Wang | url=http://www.ecns.cn/2014/04-02/107795.shtml | title=Yutu still working after expected service span ended | work=China Daily | date=2 April 2014 | access-date=9 April 2014}}</ref> ''Yutu''<nowiki/>'s scientific instruments may be functioning, but subsequent science data were very limited as the NIR spectrometer and the ground-penetrating radar were limited to the same observation as it was immobile. Mission Control planned to extend ''Yutu's'' mission until it ceased to communicate, as it would provide valuable data on its components' endurance to the lunar environment.<ref name="exceeded life" />

The rover remained operational in December 2015 and continued to transmit data every lunar day.<ref>{{cite web| url=http://www.icrosschina.com/news/2014/0528/363.shtml| title=Chinese lunar rover alive but weak| publisher=icrosschina.com| access-date=16 June 2014| archive-url=https://web.archive.org/web/20150429060356/http://www.icrosschina.com/news/2014/0528/363.shtml| archive-date=29 April 2015| url-status=dead}}</ref><ref>{{cite web| url=http://www.ecns.cn/2014/10-11/137859.shtml| title=China's ailing moon rover weakening: designer |date=October 2014}}</ref><ref>{{cite news |url= http://www.spacedaily.com/reports/Chinas_moon_rover_Yutu_functioning_but_stationary_999.html |title= China's moon rover Yutu functioning but stationary |date= 4 March 2015 |publisher= Space Daily }}</ref>

By the end of October 2015, ''Yutu'' had set the record for the longest operational period of a rover on the Moon, though most of its time was spent immobile.<ref>{{cite news |url= http://news.xinhuanet.com/english/2015-10/29/c_134763460.htm |archive-url= https://web.archive.org/web/20151102022438/http://news.xinhuanet.com/english/2015-10/29/c_134763460.htm |url-status= dead |archive-date= 2 November 2015 |title= China's first moon rover sets record for longest stay |date= 29 October 2015 |author= An |publisher= Xinhua }}</ref>

=== End of mission ===
On 3 August 2016, it was reported that the rover had ceased to communicate with ''Chang'e 3'' despite attempts to reestablish transmissions, effectively ending the mission.<ref name="nsci-20160803">{{cite news |url=https://www.newscientist.com/article/2099696-chinas-jade-rabbit-moon-rover-dead-after-31-months-on-surface |title=China's Jade Rabbit moon rover dead after 31 months on surface |last=Aron| first=Jacob| publisher=New Scientist |date=3 August 2016 |access-date=5 August 2016}}</ref><ref name="sfn-20160804">{{cite news |url=http://spaceflightnow.com/2016/08/04/chinas-yutu-rover-dies-on-the-moon/ |title=China's Yutu rover dies on the moon |author=Stephen Clark |publisher=Spaceflight Now |date=4 August 2016 |access-date=5 August 2016}}</ref>

==Discoveries==
The rover's ground penetrating radar found evidence for a minimum of nine distinct rock layers, indicating that the area had surprisingly complex geological processes and is compositionally distinct from the [[Astronomy:Apollo program|Apollo]] and Luna landing sites.<ref name="layered">{{cite news |last=Wall |first=Mike |url=http://www.space.com/28810-moon-history-chinese-lunar-rover.html?adbid=10152690360766466&adbpl=fb&adbpr=17610706465 |title=The Moon's History Is Surprisingly Complex, Chinese Rover Finds |work=Space.com |date=12 March 2015 |access-date=13 March 2015}}</ref><ref>{{cite journal |title=A young multilayered terrane of the northern Mare Imbrium revealed by Chang'E-3 mission |journal=Science |date=13 March 2015 |last=Xiao |first=Long |volume=347 |issue=6227 |pages=1226–1229 |doi=10.1126/science.1259866 |bibcode = 2015Sci...347.1226X |pmid=25766228|s2cid=206561783 }}</ref>

During 15 April 2014, the Chang'e 3 mission, including its ''Yutu'' rover, witnessed a total eclipse of the Sun by the Earth from the surface of the Moon.<ref name="authint.eclipse">{{cite news |url=https://www.authintmail.com/article/science-environment/solar-eclipse-moon |title=Solar Eclipse from the Moon |work=Authint Mail |date=7 April 2014 |url-status=dead |archive-url=https://web.archive.org/web/20140413123942/https://www.authintmail.com/article/science-environment/solar-eclipse-moon |archive-date=13 April 2014 }}</ref>

==See also==
*[[Astronomy:Chinese Lunar Exploration Program|Chinese Lunar Exploration Program]]
*[[Astronomy:Yutu-2|''Yutu-2'' rover]]
*[[Astronomy:List of artificial objects on the Moon|List of artificial objects on the Moon]]
*[[Astronomy:Lunar rover|Lunar rover]]
*[[Astronomy:Rover (space exploration)|Rover (space exploration)]]

== References ==
{{Reflist|30em}}

== External links ==
* [https://web.archive.org/web/20131215181712/http://english.cntv.cn/special/lunarmission/index.shtml Official coverage] on China Central Television (English)
* [http://www.planetary.org/blogs/emily-lakdawalla/ Snapshots from Space] at [[Organization:The Planetary Society|The Planetary Society]] website
* [http://www.zarya.info/Diaries/China/ChangE/ChangE3Diary.php#end Chang'e 3 diary] {{Webarchive|url=https://web.archive.org/web/20141129020252/http://www.zarya.info/Diaries/China/ChangE/ChangE3Diary.php#end |date=29 November 2014 }} from zarya.info
* [http://www.spaceflight101.com/change-3.html Chang'e 3 - Mission Overview] at Spaceflight101
* {{in lang|zh-cn}}[http://720yun.com/t/70b2cjpvwur?pano_id=279872 Panorama from ''Yutu'' panoramic camera (PCAM)] at 720yun website

{{Clear}}
{{Lunar rovers}}
{{Moon spacecraft}}
{{CLEP}}
{{Chinese spacecraft}}
{{Chinese space program}}
{{Solar System probes}}
{{2013 in space}}

{{DEFAULTSORT:Yutu}}
[[Category:Attached spacecraft]]
[[Category:Chinese Lunar Exploration Program]]
[[Category:Chinese space probes]]
[[Category:Lunar rovers]]

{{Sourceattribution|Yutu (rover)}}