View source for Astronomy:Yutu-2

{{short description|Chinese lunar rover}}
{{italic title}}
{{Infobox spaceflight
| name                  = ''Yutu-2''
| image                 = ChangE-4, Yutu-2 (cropped).png
| image_caption         = ''Yutu-2'' rover on the Moon as seen by the [[Astronomy:Chang'e 4|Chang'e 4]] lander
| image_size            = 300px
| mission_type          = [[Astronomy:Rover (space exploration)|lunar rover]]
| operator              = [[Organization:China National Space Administration|CNSA]]
| COSPAR_ID             =
| SATCAT                =
| mission_duration      = 3 months (planned)<ref name='B Insider 2018'>[https://www.businessinsider.com/china-moon-robot-launch-date-change-4-2018-8 China says it will launch 2 robots to the far side of the moon in December on an unprecedented lunar exploration mission] {{Webarchive|url=https://web.archive.org/web/20181209124406/https://www.businessinsider.com/china-moon-robot-launch-date-change-4-2018-8 |date=9 December 2018 }}. Dave Mosher, ''Business Insider''. 16 August 2018.</ref> <br /> Current: {{time interval|03 January 2019 02:26|show=ymd|sep=,}} 
| spacecraft_bus        =
| manufacturer          =
| dry_mass              =
| launch_mass           = Rover: 140 kg<ref name='Gunter Ch4'>[http://space.skyrocket.de/doc_sdat/change-3.htm Chang'e 3, 4 (CE 3, 4)] {{Webarchive|url=https://web.archive.org/web/20180320193603/http://space.skyrocket.de/doc_sdat/change-3.htm|date=20 March 2018}}. Gunter Dirk Krebs, ''Gunter's Space Page''.</ref>
| BOL_mass              = <!--spacecraft mass in orbit at beginning of operational life, after LEOP phase-->
| landing_mass          = 140 kg
| payload_mass          = <!--total mass of instrumentation/equipment/experiments for mission-->
| dimensions            = 1.5 × 1.0 × 1.0 m<ref name='CNN Jiang 2018'>[https://www.cnn.com/2018/08/16/asia/china-lunar-rover-intl/ This is the rover China will send to the 'dark side' of the Moon] {{Webarchive|url=https://web.archive.org/web/20180831002541/https://www.cnn.com/2018/08/16/asia/china-lunar-rover-intl/|date=31 August 2018}}.  Steven Jiang, CNN News. 16 August 2018.</ref>
| power                 = <!--end-of-life power, in watts-->
| launch_date           = 7 December 2018, 18:23 UTC<ref name="auto1">{{cite web |url=http://www.cnsa.gov.cn/n6758823/n6758838/c6804676/content.html |title=CNSA |language=zh-CN |website=[[Organization:China National Space Administration|China National Space Administration]] |access-date=8 December 2018 |archive-url=https://web.archive.org/web/20181210092044/http://www.cnsa.gov.cn/n6758823/n6758838/c6804676/content.html |archive-date=10 December 2018 |url-status=dead }}</ref>
| launch_rocket         = [[Engineering:Long March 3B|Long March 3B]]<ref name='Spaceflightnow 2018'>[https://spaceflightnow.com/launch-schedule/ Launch Schedule 2018] {{Webarchive|url=https://web.archive.org/web/20180816161152/https://spaceflightnow.com/launch-schedule/ |date=16 August 2018 }}. ''SpaceflightNow'', 18 September 2018.</ref>
| launch_site           = Xichang Satellite Launch Center
| launch_contractor     =
| disposal_type         =
| deactivated           =
| last_contact          = <!-- {{end-date|[insert date here]}} -->
|interplanetary         =
 {{Infobox spaceflight/IP
   |type                = rover
   |object              = [[Astronomy:Moon|Lunar]]
   |component           =
   |arrival_date        = 3 January 2019, 02:26 UTC<ref>{{cite news |last=Barbosa |first=Rui |title=China lands Chang'e-4 mission on the far side of the Moon |url = https://www.nasaspaceflight.com/2019/01/china-returning-moon-change-4-mission/ |work=Nasaspacefight |date=3 January 2019 |access-date=3 January 2019 |archive-url = https://web.archive.org/web/20190103063401/https://www.nasaspaceflight.com/2019/01/china-returning-moon-change-4-mission/ |archive-date=3 January 2019 |url-status=live }}</ref>
   |location            = [[Astronomy:Von Kármán (lunar crater)|Von Kármán crater]] in the South Pole-Aitken Basin
   |distance            = {{cvt|1.455|km}}<br />{{small|{{as of|2023|1|3|lc=yes}}}}{{cn|date=October 2023}}
 }}
| orbit_epoch           =
| orbit_reference       =
| orbit_regime          =
| orbit_periapsis       =
| orbit_apoapsis        =
| orbit_inclination     =
| orbit_period          =
| apsis                 =
| programme             = [[Astronomy:Chinese Lunar Exploration Program|Chinese Lunar Exploration Program]] rovers
| previous_mission      = ''[[Engineering:Yutu (rover)|Yutu]]''
| next_mission          = 
}}

'''''Yutu-2''''' ({{zh|c=玉兔二号|p=Yùtù Èrhào}}) is the robotic [[Astronomy:Lunar rover|lunar rover]] component of [[Organization:China National Space Administration|CNSA's]] [[Astronomy:Chang'e 4|Chang'e 4]] mission to the [[Astronomy:Moon|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 [[Astronomy:Far side of the Moon|far side of the Moon]] on 3 January 2019. ''Yutu-2'' is currently operational as the longest-lived lunar rover<ref>{{Cite web|title=Yutu 2 is now longest working rover on moon|url=http://english.www.gov.cn/news/topnews/201912/13/content_WS5df2db3cc6d0bcf8c4c18c3d.html|access-date=2022-01-09|website=english.www.gov.cn}}</ref> and the first lunar rover traversing the far side of the Moon.

By January 2022, ''Yutu-2'' had travelled a distance of more than {{convert|1000|m}} along the Moon's surface.<ref name="Space.com">{{cite web|title=Moon 'mystery hut' is just a rabbit-shaped rock, Chinese rover finds|date=11 January 2022|url=https://www.space.com/moon-mystery-hut-rabbit-shaped-rock-china-rover|publisher=Space.com|access-date=12 January 2022}}</ref><ref name="distance travelled">{{cite web|title=China's lunar rover Yutu 2 is on a mission to investigate mystery object on far side of the moon|url=https://www.cnet.com/news/china-moon-rover-will-investigate-cube-shaped-mystery-object-on-lunar-far-side/|date=2021-12-05}}</ref> 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.<ref name="gpr" />

==Overview==
[[File:HK WCN 灣仔北 Wan Chai North 香港會展 HKCEC 創科博覽 InnoTech Expo 玉兔二號月球車 Yutu 2 Two Luna Robot Rover December 2022 Px3 01.jpg|thumb|left|alt=Mockup of Yutu-2 rover.|Mockup of Yutu-2 rover.]]
The total landing mass is {{Convert|1200|kg|abbr=on}}.<ref name="Gunter Ch4" /> Both the stationary lander and ''Yutu-2'' rover (literally: "[[Unsolved:Moon rabbit|Jade Rabbit]]") are equipped with a [[Engineering:Radioisotope heater unit|radioisotope heater unit]] (RHU) to maintain their subsystems during the long lunar nights,<ref name="IEEE.org 2018">[https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=8544971 China Shoots for the Moon's Far Side]. (PDF) IEEE.org. 2018.</ref> while electrical power is generated by [[Physics:Solar panels on spacecraft|solar panels]].

After landing, the lander extended a ramp to deploy the ''Yutu-2'' rover  to the lunar surface.<ref name="P Society Luyuan Xu">{{cite news |last1=Xu |first1=Luyuan |title=How China's lunar relay satellite arrived in its final orbit |url=http://www.planetary.org/blogs/guest-blogs/2018/20180615-queqiao-orbit-explainer.html |work=The Planetary Society |date=15 June 2018 |archive-url=https://web.archive.org/web/20181017123833/http://www.planetary.org/blogs/guest-blogs/2018/20180615-queqiao-orbit-explainer.html |archive-date=17 October 2018}}</ref> The rover measures 1.5 × 1.0 × 1.0 m (4.9 × 3.3 × 3.3&nbsp;ft) with a mass of {{Convert|140|kg|abbr=on}},<ref name="Gunter Ch4" /><ref name="CNN Jiang 2018" /> and is propelled by six wheels. ''Yutu-2'' was manufactured in Dongguan, Guangdong province.<ref name="IEEE.org 2018" /> The rover is an improvement of the first [[Engineering:Yutu (rover)|''Yutu'' rover]] from 2013; while its nominal operating time is three months,<ref name="B Insider 2018" /> Chinese mission engineers hope it will operate for "a few years."<ref>[https://www.scmp.com/news/china/science/article/2180108/chinas-change-4-spacecraft-attempt-historic-landing-dark-side China's Chang'e 4 spacecraft to try historic landing on far side of Moon 'between January 1 and 3'] {{Webarchive|url=https://web.archive.org/web/20190102002403/https://www.scmp.com/news/china/science/article/2180108/chinas-change-4-spacecraft-attempt-historic-landing-dark-side |date=2 January 2019 }}. ''South China Morning Post''. 31 December 2018.</ref>

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==

* Panoramic Camera (PCAM), is installed on the rover's mast and can rotate 360°. It has a spectral range of 420&nbsp;nm–700&nbsp;nm and it acquires 3D images by binocular stereovision.<ref name="C4 Payload">[http://epizodyspace.ru/bibl/inostr-yazyki/planetary-and-space-science/2018/Jia_et_al_The_Chang-E-4_Mission_Planetary_and_Space_Science_in_press_(2017).pdf 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}}</ref>
* Lunar penetrating radar (LPR), is a ground penetrating radar with a probing depth of approximately 30 m with 30&nbsp;cm vertical resolution, and more than 100 m with 10 m vertical resolution.<ref name='C4 Payload'/>
* Visible and Near-Infrared Imaging Spectrometer (VNIS), for [[Physics:Imaging spectroscopy|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&nbsp;nm – 950&nbsp;nm).
* Advanced Small Analyzer for Neutrals (ASAN), is an [[Astronomy:Energetic neutral atom|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 [[Astronomy:Lunar water|lunar water]].<ref name="GT-lunar-Sweden">{{Cite web |url=https://gbtimes.com/sweden-joins-chinas-historic-mission-land-far-side-moon?feature=chinas-change-4-mission-to-the-far-side-of-the-moon |title=Sweden joins China's historic mission to land on the far side of the Moon in 2018 |author=Andrew Jones |work=GBTimes |date=16 May 2016 |access-date=12 January 2018 |archive-date=6 October 2018 |archive-url=https://web.archive.org/web/20181006114659/https://gbtimes.com/sweden-joins-chinas-historic-mission-land-far-side-moon?feature=chinas-change-4-mission-to-the-far-side-of-the-moon |url-status=dead }}</ref>

==Cost==
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).<ref>[http://www.ecns.cn/m/news/sci-tech/2019-07-31/detail-ifzmnmiq8702425.shtml 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<!-- Bot generated title -->]</ref>

==Landing site==
The landing site is within the [[Astronomy:Von Kármán (lunar crater)|Von Kármán]] crater<ref name="A&S">[https://www.airspacemag.com/daily-planet/chinas-journey-lunar-far-side-missed-opportunity-180963703/ China's Journey to the Lunar Far Side: A Missed Opportunity?] Paul D. Spudis, ''Air & Space Smithsonian''. 14 June 2017.</ref> ({{Convert|180|km||abbr=on|disp=or}} diameter) in the South Pole-Aitken Basin on the [[Astronomy:Far side of the Moon|far side of the Moon]], which was previously unexplored by landers.<ref name="Overview">{{Cite journal |doi=10.1007/s11431-016-9034-6 |title=An overview of the mission and technical characteristics of Change'4 Lunar Probe |journal=Science China Technological Sciences |volume=60 |issue=5 |pages=658 |year=2017 |last1=Ye |first1=Peijian |last2=Sun |first2=Zezhou |last3=Zhang |first3=He |last4=Li |first4=Fei|bibcode=2017ScChE..60..658Y |s2cid=126303995 }}</ref><ref>{{cite news |url=http://www.spacedaily.com/reports/China_Plans_First_Ever_Landing_on_the_Dark_Side_of_the_Moon_999.html |title=China Plans First Ever Landing on the Lunar Far Side |date=22 May 2015 |publisher=Space Daily |access-date= 26 May 2015 |archive-url= https://web.archive.org/web/20150526115025/http://www.spacedaily.com/reports/China_Plans_First_Ever_Landing_on_the_Dark_Side_of_the_Moon_999.html |archive-date= 26 May 2015 |url-status= live }}</ref> The site has symbolic as well as scientific value: [[Biography:Theodore von Kármán|Theodore von Kármán]] was the PhD advisor of [[Biography:Qian Xuesen|Qian Xuesen]], the founder of the Chinese space program.<ref>{{cite web |title=Hsue-Shen Tsien |url=https://www.genealogy.math.ndsu.nodak.edu/id.php?id=114672 |website=Mathematics Genealogy Project |access-date=7 December 2018 |archive-url=https://web.archive.org/web/20181209124216/https://www.genealogy.math.ndsu.nodak.edu/id.php?id=114672 |archive-date=9 December 2018 |url-status=live}}</ref>

==Operations and results==
A few days after landing, ''Yutu-2'' went into hibernation for its first lunar night and it resumed activities on 29 January 2019, with all instruments operating nominally. During its first full lunar day, the rover travelled {{cvt|120|m|abbr=on}}, and on 11 February 2019 it powered down for its second lunar night.<ref>{{cite web |last=Jones |first=Andrew |url=https://spacenews.com/change-4-powers-down-for-second-lunar-night/ |title=Chang'e-4 powers down for second lunar night |work=SpaceNews |date=11 February 2019 |access-date=1 August 2019}}</ref><ref>{{cite web |last=Caraiman |first=Vadim Ioan |url=https://greatlakesledger.com/2019/02/11/chinese-lunar-probe-change-4-goes-standby-mode-for-the-second-lunar-night-on-the-dark-side-of-the-moon/ |title=Chinese Lunar Probe, Chang'e-4, Goes Standby Mode For The Second Lunar Night on The Dark Side of The Moon  |work=Great Lakes Ledger |date=11 February 2019 |access-date=1 August 2019}}</ref> In May 2019, it was reported that Chang'e 4 has identified what appear to be mantle rocks on the surface, its primary objective.<ref name='Nature 10.1038'>{{Cite journal|last1=Ouyang|first1=Ziyuan|last2=Zhang|first2=Hongbo|last3=Su|first3=Yan|last4=Wen|first4=Weibin|last5=Shu|first5=Rong|last6=Chen|first6=Wangli|last7=Zhang|first7=Xiaoxia|last8=Tan|first8=Xu|last9=Xu|first9=Rui|date=May 2019|title=Chang'E-4 initial spectroscopic identification of lunar far-side mantle-derived materials|journal=Nature|volume=569|issue=7756|pages=378–382|doi=10.1038/s41586-019-1189-0|pmid=31092939|issn=1476-4687|bibcode=2019Natur.569..378L|s2cid=205571018}}</ref><ref>{{Cite web |last=Strickland |first=Ashley |url=https://www.cnn.com/2019/05/15/world/change4-far-side-of-moon-mission-scn/index.html |title=Chinese mission uncovers secrets on the far side of the moon |website=CNN |date=2019-05-15 |access-date=2019-05-16}}</ref><ref>{{cite web |last=Rincon |first=Paul |url=https://www.bbc.com/news/science-environment-48285503 |title=Chang'e-4: Chinese rover 'confirms' Moon crater theory |work=BBC News |date=15 May 2019 |access-date=1 August 2019}}</ref>

In December 2019, ''Yutu 2'' broke the lunar longevity record, previously held by the Soviet Union's ''[[Astronomy:Lunokhod 1|Lunokhod 1]]'' rover,<ref>[https://www.space.com/china-change-4-rover-moon-record.html China's Farside Moon Rover Breaks Lunar Longevity Record.] Leonard David, ''Space.com''. 12 December 2019.</ref> which operated on the lunar surface for eleven lunar days (321 Earth days) and traversed a total distance of {{cvt|10.54|km}}.<ref>Howell, Elizabeth (December 19, 2016). "[https://www.space.com/35090-lunokhod-1.html Lunokhod 1: 1st Successful Lunar Rover"], Space.com.  Retrieved May 31, 2018.</ref>

In February 2020, Chinese astronomers reported, for the first time, a high-resolution image of a [[Astronomy:Geology of the Moon#Geologic history|lunar ejecta sequence]], and, as well, direct analysis of its internal architecture. These were based on observations made by the rover's [[Earth:Ground-penetrating radar|Lunar Penetrating Radar]] (LPR).<ref name="NYT-20200226">{{cite news |last=Chang |first=Kenneth |title=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. |url=https://www.nytimes.com/2020/02/26/science/china-moon-far-side.html |date=26 February 2020 |work={{wipe|The New York Times}} |access-date=27 February 2020 }}</ref><ref name="SA-20200226">{{cite journal |author=Li, Chunlai |display-authors=et al. |title=The Moon's farside shallow subsurface structure unveiled by Chang'E-4 Lunar Penetrating Radar |date=26 February 2020 |journal=Science Advances |volume=6 |issue=9 |pages=eaay6898 |doi=10.1126/sciadv.aay6898 |pmid=32133404 |pmc=7043921 |bibcode=2020SciA....6.6898L |doi-access=free }}</ref>

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",<ref name="NYT-20211208">{{cite news |author1=Shannon Stirone|title=Moon Cube and Mysteries of the Solar System |url=https://www.nytimes.com/interactive/2021/12/08/science/moon-cube-pictures.html |date=8 December 2021 |work={{wipe|The New York Times}} |accessdate=27 December 2021 }}</ref><ref name="INV-20211208">{{cite news |last=Kelvey |first=Jon |title=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. |url=https://www.inverse.com/science/look-chinese-rover-spots-a-moon-cube-opens-a-new-lunar-mystery |date=8 December 2021 |work=Inverse |accessdate=27 December 2021 }}</ref> which it was intended to explore in the following lunar days (earth months).<ref name="Space-20211206">{{cite news |last=Jones |first=Andrew |title=China's Yutu 2 rover spots cube-shaped 'mystery hut' on far side of the moon. |url=https://www.space.com/china-yutu-2-moon-rover-cube-shaped-object-photos |date=5 December 2021 |work=Space.com |access-date=6 December 2021}}</ref><ref name="CNET-20211205">{{cite news |last=Kooser |first=Amanda |title=China moon rover will investigate cube-shaped 'mystery' object on lunar far side - Is that a boulder? Or something else? |url=https://www.cnet.com/news/china-moon-rover-will-investigate-cube-shaped-mystery-object-on-lunar-far-side/ |date=5 December 2021 |work=CNET |accessdate=6 December 2021 }}</ref> 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";<ref name="GIZ-20220107">{{cite news |last=Dvorsky |first=George |title='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. |url=https://gizmodo.com/mysterious-hut-spotted-on-far-side-of-the-moon-is-a-h-1848321899 |date=7 January 2022 |work=Gizmodo|accessdate=7 January 2022 }}</ref> resembling a rabbit, with a smaller nearby rock like a carrot, making a fitting discovery for the ''Yutu'' (Jade Rabbit).<ref name="NYT-20220107">{{cite news |last=Chang |first=Kenneth |title=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. |url=https://www.nytimes.com/2022/01/07/science/moon-cube-china-rover.html |date=7 January 2022 |work={{wipe|The New York Times}} |accessdate=7 January 2022 }}</ref>

{{wide image |The routing path of the Yutu-2 rover.png|800px|align-cap=center|The routing path of the ''Yutu-2'' rover.}}

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.<ref name="gpr">{{cite web|title=China's Yutu 2 rover reveals deep layers below far side of the moon|website=Space.com |url=https://www.space.com/china-chang-e-4-yutu-2-rover-moon-subsurface-layers|date=2023-08-24}}</ref>
==See also==
* [[Astronomy:Chinese Lunar Exploration Program|Chinese Lunar Exploration Program]]
* [[Astronomy:Chang'e 4|Chang'e 4]]
* [[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}}

{{Lunar rovers}}
{{Moon spacecraft}}
{{CLEP}}
{{Chinese spacecraft}}
{{Chinese space program}}
{{Solar System probes}}
{{2018 in space}}
{{2019 in space}}

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

{{Sourceattribution|Yutu-2}}