Chang'e 3

Overview

The Chinese Lunar Exploration Program is designed to be conducted in four phases of incremental technological advancement: The first is simply reaching lunar orbit, a task completed by Chang'e 1 in 2007 and Chang'e 2 in 2010. The second is landing and roving on the Moon, as Chang'e 3 did in 2013 and Chang'e 4 did in 2019. The third is collecting lunar samples from the near-side and sending them to Earth, a task done by Chang'e 5 and Chang'e 6 missions. The fourth phase consists of development of a robotic research station near the Moon's south pole. The program aims to facilitate a crewed lunar landing in the 2030s and possibly build an outpost near the south pole.

History

In January 2004, China's lunar orbiter project was formally established. The first Chinese lunar orbiter, Chang'e 1, was launched from Xichang Satellite Launch Center on 24 October 2007 and entered lunar orbit on 5 November. The spacecraft operated until 1 March 2009, when it was intentionally crashed into the surface of the Moon. Data gathered by Chang'e 1 were used to create an accurate and high-resolution 3D map of the entire lunar surface, assisting site selection for the Chang'e 3 lander.

Chang'e 1's successor, Chang'e 2, was approved in October 2008 and was launched on 1 October 2010 to conduct research from a 100-km-high lunar orbit, in preparation for Chang'e 3's 2013 soft landing. Chang'e 2, though similar in design to Chang'e 1, was equipped with improved instruments and provided higher-resolution imagery of the lunar surface to assist in the planning of the Chang'e 3 mission. In 2012, Chang'e 2 was dispatched on an extended mission to the asteroid 4179 Toutatis.

Objectives

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. The scientific objectives of Chang'e 3 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. 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, and investigate the lunar crust structure down to several hundred meters deep.

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

• Orbiting (Chang'e 1 and Chang'e 2)
• Landing (Chang'e 3 and Chang'e 4)
• Sample return (Chang'e 5 and Chang'e 6)

Mission profile

Launch

Chang'e 3 was launched at 17:30 UTC on 1 December 2013 (01:30 local time on 2 December) atop a Long March 3B rocket flying from Launch Complex 2 at the Xichang Satellite Launch Centre in the southwestern province of Sichuan.

Homes downrange of the Launch Centre were damaged during liftoff when spent hardware wreckage from the rocket, including one piece the size of a desk, fell on a village in Suining County in neighbouring Hunan province. The county authorities had moved 160,000 people to safety before the liftoff, while more than 20,000 people near the launch site in Sichuan had been moved to a primary school auditorium. The expected wreckage zone for Long March rockets is 50 to long and 30 km wide.

Landing

Chang'e 3 entered a 100 km-high circular lunar orbit on 6 December 2013, 9:53 UTC. The orbit was obtained after 361 seconds (6 minutes) of variable thrust engine braking from its single main engine. Later, the spacecraft adopted a 15 × elliptic orbit. The landing took place one week later, on 14 December. At periapsis, its variable thrusters were again fired in order to reduce its velocity, descending to 100 m above the Moon's surface. It hovered at this altitude, moving horizontally under its own guidance to avoid obstacles, before slowly descending to 4 m above the ground, at which point its engine was shut down for a free-fall onto the lunar surface. The landing sequence took about 12 minutes to complete.

Topographic data from the Chang'e 1 and 2 orbiters were used to select a landing site for Chang'e 3. The planned landing site was Sinus Iridum, but the lander actually descended on Mare Imbrium, about 40 km south of the 6 km diameter crater Laplace F, at 44.1214°N, 19.5116°W and 2640 m elevation, on 14 December 2013, 13:11 UTC.

Lander

With a landing mass of 1200 kg, it also carried and deployed the 140 kg rover. It serves double-duty as a technology demonstrator to be further refined for the planned 2019 Chang'e 5 and 6 sample-return missions.

The stationary lander is equipped with a radioisotope heater unit (RHU) in order to heat its subsystems and power its operations, along with its solar panels, during its planned one-year mission. It has a scientific payload of seven instruments and cameras. In addition to their lunar scientific roles, the cameras will also acquire images of the Earth and other celestial bodies. During the 14-day lunar nights, the lander and the rover go into 'sleep mode'.

Lunar-based ultraviolet telescope (LUT)

The lander is equipped with a 50 mm Ritchey–Chrétien telescope that is being used to observe galaxies, active galactic nuclei, variable stars, binaries, novae, quasars and blazars in the near-UV band (245–340 nm), and is capable of detecting objects at a brightness as low as magnitude 13. The thin exosphere and slow rotation of the Moon allow extremely long, uninterrupted observations of a target. The LUT is the first long term lunar-based astronomical observatory, making continuous observations of important celestial bodies to study their light variation and better improve current models.

Extreme ultraviolet (EUV) camera

The lander also carries an extreme ultraviolet (30.4 nm) camera, which will be used to observe the Earth's plasmasphere in order to examine its structure and dynamics and to investigate how it is affected by solar activity.

Lander cameras

Three panoramic cameras are installed on the lander, facing different directions. The lander is equipped with a single descent camera that was tested on the Chang'e 2 spacecraft.

Soil probe

The Chang'e 3 lander also carries an extensible soil probe.

Rover

Main article: Yutu (rover)

The development of the six-wheeled rover began in 2002 at the Shanghai Aerospace System Engineering Institute and was completed in May 2010. The rover has a total mass of approximately 140 kg, with a payload capacity of approximately 20 kg. The rover may transmit video in real time, and can perform simple analysis of soil samples. It can navigate inclines and has automatic sensors to prevent it from colliding with other objects.

Energy was provided by 2 solar panels, allowing the rover to operate through lunar days, as well as charging its batteries. At night the rover was powered down to a large extent, and kept from getting too cold by the use of several radioisotope heater units (RHUs) using plutonium-238. The RHUs provide only thermal energy and no electricity.

The rover was deployed from the lander, and made contact with the lunar surface on 14 December, 20:35 UTC. On 17 December it was announced that all of the scientific tools apart from the spectrometers had been activated, and that both the lander and rover were "functioning as hoped, despite the unexpectedly rigorous conditions of the lunar environment". However, from 16 to 20 December the rover did not move, having shut down its subsystems. 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. Since then, the lander and rover finished taking pictures of each other and commenced their respective science missions.

The rover was designed to explore an area of 3 sqkm during its 3-month mission, with a maximum travelling distance of 10 km.

The rover demonstrated its ability to endure its first lunar night when it was commanded out of sleep mode on 11 January 2014. On 25 January 2014, China's state media announced the rover had undergone a "mechanical control abnormality" caused by the "complicated lunar surface environment".

The rover established contact with mission control on 13 February 2014, but it was still suffering from a "mechanical abnormality". The rover was still intermittently transmitting as late as 6 September 2014. It ceased to transmit data in March 2015.

Ground-penetrating radar (GPR)

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, and investigation of the lunar crust structure down to several hundred meters deep.

Spectrometers

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

Stereo cameras

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

Monitoring by other lunar missions

The descent of the Chang'e 3 spacecraft was expected to increase the content of lunar dust in the tenuous lunar exosphere, as well as introduce gases from engine firings during landing. Although there is no formal cooperation between NASA and the China National Space Administration, the landing provided an opportunity for NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE) mission to examine possible changes to the baseline readings of the Moon's exosphere, and will allow it to study how dust and spent propellant gases settle around the Moon after a landing. For example, one of the lander's combustion byproducts is water vapor, and LADEE may be able to observe how lunar water is deposited in cold traps near the poles. NASA's Lunar Reconnaissance Orbiter (LRO) took a photograph of the landing site on 25 December 2013 in which the lander and the rover can be seen. LRO also attempted to photograph the lander and rover on 22 January 2014, and on 18 February 2014.

Status

The rover was still intermittently transmitting as late as 6 September 2014. As of March 2015, the rover remained immobile and its instruments continued degrading, but was still able to communicate with Earth radio stations. 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.

The Yutu rover ceased to transmit data in March 2015. Status checks of the lander and its Lunar-based Ultraviolet Telescope (LUT) in 2018, 2020, and 2025, indicate that the spacecraft is still operational, roughly twelve years after landing on the Moon. The power source for the lander, which consists of a radioisotope heater unit (RHU) and solar panels, could last for 30 years.

Chang'e 3 landing site named 'Guang Han Gong'

The landing site of China's first Moon lander Chang'e 3 has been named "Guang Han Gong（广寒宫） (Guang: widely, extensively; Han: cold, freezing；Gong: Palace) " or "Moon Palace" by the International Astronomical Union (IAU), China's State Administration of Science, Technology and Industry for National Defense (SASTIND). Three nearby impact craters were given the names Zi Wei, Tian Shi and Tai Wei, three constellations in traditional Chinese astrology.

References

| access-date= 5 December 2013 | archive-date= 20 October 2016 | archive-url= https://web.archive.org/web/20161020063743/http://www.americaspace.com/?p=35272 | url-status= live }}

| access-date= 5 April 2012 | archive-date= 2 November 2013 | archive-url= https://web.archive.org/web/20131102051825/http://www.asianscientist.com/topnews/chang-e-3-china-first-moon-rover-launch-in-2013/ | url-status= live }}

| access-date= 2 December 2013 | archive-date= 18 April 2010 | archive-url= https://web.archive.org/web/20100418193148/http://www.atimes.com/atimes/China/LD16Ad01.html | url-status= unfit }}

| access-date= 26 April 2019 | archive-date= 29 May 2019 | archive-url= https://web.archive.org/web/20190529135046/https://www.theatlantic.com/international/archive/2013/12/china-becomes-third-country-ever-soft-land-moon/356151/ | url-status= live }}

| access-date= 20 June 2018 | archive-date= 12 January 2020 | archive-url= https://web.archive.org/web/20200112042913/https://www.bbc.co.uk/news/science-environment-25356603 | url-status= live }}

| access-date= 15 December 2013 | archive-date= 14 December 2013 | archive-url= https://web.archive.org/web/20131214150756/http://www.bbc.co.uk/news/25141597 | url-status= live }}

| access-date= 15 December 2013 | archive-date= 2 February 2021 | archive-url= https://web.archive.org/web/20210202164826/http://planetary.s3.amazonaws.com/assets/images/3-moon/20131214_change_landing_location.jpg | url-status= live }}

| access-date= 13 February 2014 | archive-date= 22 October 2017 | archive-url= https://web.archive.org/web/20171022193915/http://www.cnn.com/2014/02/12/world/asia/jade-rabbit-resurrection/index.html?hpt=wo_c2 | url-status= live }}

| access-date= 9 December 2013 | archive-date= 13 December 2013 | archive-url= https://web.archive.org/web/20131213041953/http://english.cntv.cn/20131126/103212.shtml | url-status= dead }}

| access-date= 2 December 2013 | archive-date= 21 October 2013 | archive-url= https://web.archive.org/web/20131021091125/http://english.cri.cn/6909/2012/03/13/53s686639.htm | url-status= dead }}

| 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 }}

| access-date= 4 March 2015 | archive-date= 16 March 2015 | archive-url= https://web.archive.org/web/20150316234141/http://www.ecns.cn/2014/10-11/137859.shtml | url-status= live }}

| access-date= 7 January 2016 | archive-date= 7 January 2016 | archive-url= https://web.archive.org/web/20160107195040/http://www.ecns.cn/2016/01-05/194755.shtml | url-status= live }}

| access-date= 25 June 2018 | archive-date= 30 November 2018 | archive-url= https://web.archive.org/web/20181130123749/https://gbtimes.com/the-change-3-lunar-lander-is-still-waking-up-after-nearly-five-years-on-the-moon | url-status= dead }}

| access-date= 15 August 2018 | archive-date= 17 May 2019 | archive-url= https://web.archive.org/web/20190517063331/https://gbtimes.com/chinas-telescope-moon-still-working-and-could-do-30-years | url-status= dead }}

| archive-date= 25 October 2016 | archive-url= https://web.archive.org/web/20161025190202/https://www.theguardian.com/world/2013/dec/04/rocket-debris-hits-chinese-village | url-status= dead }}

| access-date= 4 March 2015 | archive-date= 29 April 2015 | archive-url= https://web.archive.org/web/20150429060356/http://www.icrosschina.com/news/2014/0528/363.shtml | url-status= dead }}

| archive-date= 3 March 2021 | archive-url= https://web.archive.org/web/20210303084605/http://epizodsspace.airbase.ru/bibl/inostr-yazyki/Chinese_Journal_of_Space_Science/2018/5/Xu_et_al_China%27s_Planning_---before_2030_Chin_J_Space_Sci_38%282018%29.pdf | url-status= live }}

| access-date= 26 December 2013 | archive-date= 13 April 2019 | archive-url= https://web.archive.org/web/20190413122516/https://www.lunarenterprisedaily.com/2013/04/22/tuesday-23-april-2013/ | 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 | url-status= live }}

| access-date= 14 November 2008 | archive-date= 16 November 2017 | archive-url= https://web.archive.org/web/20171116084928/http://mil.news.sina.com.cn/s/2008-11-12/1559529860.html | url-status= live

| access-date= 1 January 2014 | archive-date= 2 January 2014 | archive-url= https://web.archive.org/web/20140102184050/http://www.nasa.gov/content/nasa-images-of-change-3-landing-site/ | url-status= dead }}

| access-date= 8 December 2013 | archive-date= 13 December 2013 | archive-url= https://web.archive.org/web/20131213021728/http://news.163.com/13/1202/02/9F2BAFI200014AED_all.html | url-status= dead

| access-date= 14 December 2013 | archive-date= 31 December 2017 | archive-url= https://web.archive.org/web/20171231074050/https://www.nasaspaceflight.com/2013/12/china-jade-rabbit-lunar-arrival/ | url-status= live }}

| access-date= 2 December 2013 | archive-date= 27 June 2018 | archive-url= https://web.archive.org/web/20180627034644/https://sinosphere.blogs.nytimes.com/2013/11/26/china-to-send-jade-rabbit-rover-to-the-moon/?_r=1 | url-status= live }}

| access-date= 29 December 2015 | archive-date= 19 September 2018 | archive-url= https://web.archive.org/web/20180919113055/https://www.nytimes.com/2015/12/29/science/new-type-of-rock-is-discovered-on-moon.html | url-status= live }}

| access-date= 2 October 2014 | archive-date= 1 October 2014 | archive-url= https://web.archive.org/web/20141001215030/http://phys.org/news/2014-09-china-yutu-rover-alive-lunar.html | url-status= live }}

| access-date= 4 March 2015 | archive-date= 23 July 2014 | archive-url= https://web.archive.org/web/20140723022011/http://politics.people.com.cn/n/2014/0719/c1001-25303056.html | url-status= live }}

| 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 }}

| access-date= 21 July 2022 | archive-date= 29 November 2018 | archive-url= https://web.archive.org/web/20181129225204/https://qz.com/1262581/china-lays-out-its-ambitions-to-colonize-the-moon-and-build-a-lunar-palace/ | url-status= live }}

| access-date= 4 April 2015 | archive-date= 2 December 2017 | archive-url= https://web.archive.org/web/20171202002605/http://www.scmp.com/article/1747790/top-scientist-ma-xingrui-named-party-chief-shenzhen | url-status= live }}

| access-date= 2 December 2013 | archive-date= 3 December 2013 | archive-url= https://web.archive.org/web/20131203221401/http://www.spaceflight101.com/change-3.html | url-status= dead }}

| access-date= 20 January 2014 | archive-date= 29 November 2014 | archive-url= https://web.archive.org/web/20141129031804/http://www.spaceflight101.com/change-3-mission-updates.html | url-status= dead }}

| access-date= 20 November 2014 | archive-date= 29 November 2014 | archive-url= https://web.archive.org/web/20141129031804/http://www.spaceflight101.com/change-3-mission-updates.html | url-status= dead }}

| access-date= 2 October 2010 | archive-date= 18 July 2018 | archive-url= https://web.archive.org/web/20180718234436/https://spaceflightnow.com/news/n1010/01change2launch/ | url-status= live }}

| access-date= 13 October 2015 }}

| access-date= 24 November 2013 | archive-date= 25 November 2013 | archive-url= https://web.archive.org/web/20131125234921/http://www.space.com/23675-china-moon-lander-trouble-nasa-ladee.html | url-status= live }}

| access-date= 13 March 2015 | archive-date= 4 August 2017 | archive-url= https://web.archive.org/web/20170804053347/https://www.space.com/28810-moon-history-chinese-lunar-rover.html?adbid=10152690360766466&adbpl=fb&adbpr=17610706465 | url-status= live }}

| access-date= 23 July 2013 | archive-date= 22 August 2017 | archive-url= https://web.archive.org/web/20170822183253/https://www.space.com/21618-china-moon-rover-launch-2013.html | url-status= live }}

| access-date= 17 December 2013 | archive-date= 20 December 2013 | archive-url= https://web.archive.org/web/20131220210245/http://www.space.com/23968-china-moon-rover-historic-lunar-landing.html | url-status= dead }}

| access-date= 16 November 2020 | archive-date= 25 November 2020 | archive-url= https://web.archive.org/web/20201125043612/https://www.space.com/china-change-3-moon-lander-lasts-7-years | url-status= live }}

| access-date= 8 December 2013 | archive-date= 7 May 2016 | archive-url= https://web.archive.org/web/20160507043303/http://www.spacedaily.com/reports/China_moon_rover_enters_lunar_orbit_Xinhua_999.html | url-status= live }}

| access-date= 4 March 2015 | archive-date= 18 March 2015 | archive-url= https://web.archive.org/web/20150318065046/http://www.spacedaily.com/reports/Chinas_moon_rover_Yutu_functioning_but_stationary_999.html | url-status= live }}

| access-date= 9 December 2013 | archive-date= 5 December 2013 | archive-url= https://web.archive.org/web/20131205231808/http://www.thewire.com/global/2013/12/china-space-launch/355650/ | url-status= dead }}

| access-date= 16 June 2012 | archive-date= 8 January 2018 | archive-url= https://web.archive.org/web/20180108131345/http://www.planetary.org/blogs/emily-lakdawalla/2012/06150926-change2-update.html | url-status= live }}

| access-date= 2 December 2013 | archive-date= 21 April 2012 | archive-url= https://web.archive.org/web/20120421020137/http://www.planetary.org/explore/topics/chang_e_1/ | url-status= dead }}

| access-date= 15 December 2013 | archive-date= 22 June 2020 | archive-url= https://web.archive.org/web/20200622004315/https://www.planetary.org/blogs/emily-lakdawalla/2013/12140619-change-3-has-successfully-landed.html | url-status= live }}

| access-date= 6 December 2013 | archive-date= 7 December 2013 | archive-url= https://web.archive.org/web/20131207030852/http://www.planetary.org/blogs/emily-lakdawalla/2013/12051704-change-3-and-ladee-updates.html | url-status= live }}

| access-date= 24 December 2013 | 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 | url-status= live }}

| access-date= 4 March 2015 | archive-date= 14 July 2014 | archive-url= https://web.archive.org/web/20140714144131/http://www.unmannedspaceflight.com/index.php?showtopic=7802&st=75&start=75 | url-status= dead }}

| access-date= 4 March 2015 | archive-date= 6 October 2014 | archive-url= https://web.archive.org/web/20141006110144/http://www.unmannedspaceflight.com/index.php?showtopic=7802&st=90&start=90 | url-status= dead }}

| display-authors= etal

| access-date= 26 October 2007 | archive-date= 25 October 2007 | archive-url= https://web.archive.org/web/20071025235924/http://news.xinhuanet.com/english/2007-10/24/content_6937622.htm | url-status= dead }}

| access-date= 24 April 2008 | archive-date= 27 February 2009 | archive-url= https://web.archive.org/web/20090227143654/http://news.xinhuanet.com/tech/2008-04/24/xinsrc_332040524080250082374.jpg | url-status= dead }}

| access-date= 24 April 2008 | archive-date= 27 February 2009 | archive-url= https://web.archive.org/web/20090227143656/http://news.xinhuanet.com/tech/2008-04/24/xinsrc_332040524080210976603.jpg | url-status= dead }}

| access-date= 3 March 2009 | archive-date= 2 March 2009 | archive-url= https://web.archive.org/web/20090302170937/http://news.xinhuanet.com/english/2009-03/01/content_10923205.htm | url-status= dead }}

| access-date= 1 October 2010 | archive-date= 31 May 2009 | archive-url= https://web.archive.org/web/20090531002641/http://news.xinhuanet.com/english/2009-05/24/content_11425131.htm | url-status= dead }}

| access-date= 23 July 2013 | archive-date= 17 June 2012 | archive-url= https://web.archive.org/web/20120617020908/http://news.xinhuanet.com/politics/2012-06/14/c_112217044.htm | url-status= dead }}

| access-date= 6 December 2013 | archive-date= 7 December 2013 | archive-url= https://web.archive.org/web/20131207030850/http://news.xinhuanet.com/english/china/2013-12/06/c_132947629.htm | url-status= dead }}

| access-date= 19 December 2013 | archive-date= 18 December 2013 | archive-url= https://web.archive.org/web/20131218121731/http://news.xinhuanet.com/english/china/2013-12/18/c_132977079.htm | url-status= dead }}

| access-date= 21 December 2013 | archive-date= 24 December 2013 | archive-url= https://web.archive.org/web/20131224053039/http://news.xinhuanet.com/english/china/2013-12/20/c_125893854.htm | url-status= dead }}

| 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 }}

| archive-date= 22 October 2013 | archive-url= https://web.archive.org/web/20131022000601/http://www.zarya.info/Diaries/Launches/Launches.php?year=2013#070 | url-status= dead }}