Chang'e 5 probe separating from the launcher (artist's impression)
|Mission type||Lunar sample return|
|Mission duration||Primary Mission: 22 days, 21 hours, 29 minutes|
Extended Mission: 54 days, 2 hours, 19 minutes
|Launch mass||8,200 kg (18,100 lb)|
|Start of mission|
|Launch date||23 November 2020|
24 November 2020
|Rocket||Long March 5|
|End of mission|
|Landing date||16 December 2020, 17:59 UTC|
|Landing site||Inner Mongolia, China|
|Orbital insertion||28 November 2020|
|Periapsis altitude||400 km (250 mi)|
|Landing date||1 December 2020|
|Return launch||3 December 2020|
|Landing site||Mons Rümker, region of Oceanus Procellarum|
|Sample mass||1,731 g (61.1 oz)|
Chang'e 5 (Chinese: 嫦娥五号; pinyin: Cháng'é wǔhào[note 1]) is the fifth lunar exploration mission of the Chinese Lunar Exploration Program, and China's first lunar sample-return mission. Like its predecessors, the spacecraft is named after the Chinese moon goddess Chang'e. It launched at 20:30 UTC on November 23, 2020 from Wenchang Spacecraft Launch Site on Hainan Island, landed on the Moon on December 1, 2020, sampled ~1,731 g (61.1 oz) of lunar samples (including a ~1 m core), and returned to the Earth at 17:59 UTC on 16 December 2020.
Chang'e-5 mission is the first lunar sample-return mission conducted by humanity in over four decades since the Soviet Union's Luna 24 in 1976. By completing the mission, China became the third country to return samples from the Moon after the United States and the Soviet Union.
The Chang'e-5 mission consists of four modules or components:
The four components were launched together and fly to the Moon as a combined unit. After reaching the lunar orbit (14:58 UTC November 28, 2020), the Lander/Ascender separated from the Orbiter/Returner modules (20:40 UTC November 29, 2020), and descended to the surface of the Moon (15:13 UTC, December 1, 2020). After samples have been collected, the Ascender separated from the Lander (15:11 UTC, December 3, 2020), lifted off to the Orbiter/Returner, docked with them, and transferred the samples to the Returner. The Ascender then separated from the Orbiter/Returner and smashed at the Moon (~30°S in latitude and 0° in longitude) at 22:49 UTC December 8, 2020. The Orbiter/Returner then returned to the Earth, where the Returner separated and descended to the surface of the Earth at 17:59 UTC December 16, 2020.
The estimated launch mass of Chang'e-5 is 8,200 kg (18,100 lb), the Lander is projected to be 1,200 kg (2,600 lb) and Ascender is about 500 kg (1,100 lb). Unlike Chang'e 4, which was equipped with a radioisotope heater unit to survive the extreme cold of lunar night, the Lander of Chang'e-5 ended in the following lunar night.
Chang'e-5 includes four scientific payloads, including a Landing Camera, a Panoramic Camera, a Lunar Mineralogical Spectrometer, and a Lunar Regolith Penetrating Radar. Chang'e-5 collected samples using two methods, i.e., drilling for subsurface samples and scooping for surface samples. The scooping device was developed by The Hong Kong Polytechnic University, consisting of Sampler A, Sampler B, Near-field Cameras, and Sealing and Packaging System.
Chang'e 5 was planned to be launched in November 2017 by the Long March 5 rocket; however, a July 2017 failure of the referenced carrier rocket forced a delay to the original schedule two times until the end of 2020. On 27 December 2019, the Long March 5 successfully returned to services, thereby allowing the current mission to proceed after Tianwen-1 mission. The Chang'e 5 probe was launched at 20:30 UTC November 23, 2020, by Long March 5 Y-5 rocket from the Wenchang Spacecraft Launch Site on Hainan Island.
After launch, Chang'e-5 applied its first orbital correction at 14:06 UTC November 24, 2020, second orbital correction at 14:06 UTC November 25, 2020, entered the lunar orbital at 14:58 UTC November 28 (elliptical orbital), adjusted its orbit to a circular orbit at 12:23 UTC November 29, 2020, and the Lander/Ascender separated from the Orbiter/Returner at 20:10 UTC November 29, 2020, in preparing for landing.
The Lander/Ascender landed on the Moon on 1 December 2020 at 15:11 UTC. The Chang'e 5 landing site is at 43.1°N (in latitude), 51.8°W (in longitude) in the Northern Oceanus Procellarum near a huge volcanic complex, Mons Rümker, located in the northwest lunar near side. The Chang'e 5 landing site is within the Procellarum KREEP Terrain, with elevated heat-producing elements, thin crust, and prolonged volcanism. This area is characterized by some of the youngest mare basalts on the Moon (~1.21 billion years old), with elevated titanium, thorium, and olivine abundances, which have never been sampled by Apollo or Luna mission. It is hoped that the young age of the returned samples collected will allow scientists to improve our understanding of the lunar impact and late thermal evolution history.
The Chang'e 5 Ascender lifted off from Oceanus Procellarum at 15:10 UTC December 3, 2020, and six minutes later, arrived the lunar orbit. The Ascender docked with the Orbiter/Returner combination in the lunar orbit on 5 December 2020 at 21:42 UTC, and the samples were transferred to the return capsule at 22:12 UTC. The Ascender separated from the Orbiter/Returner combination on 6 December 2020 at 04:35 UTC. After completing its role of the mission, the Ascender was commanded to deorbit on 7 December 2020, at 22:59 UTC, and crashed into the Moon's surface at 23:30 UTC, in the area of (~30°S, 0°E). On 13 December 2020 at 01:51 UTC, from a distance of 230 kilometers from the lunar surface, the Orbiter and Returner successfully fired four engines to enter the Moon-Earth Hohmann transfer orbit.
The electronics and systems on the Chang'e 5 lunar lander were expected to cease working on 11 December 2020, due to the Moon's extreme cold and lack of a radioisotope heater unit. However, engineers were also prepared for the possibility that the Chang'e 5 lander could be damaged and stop working after acting as the launchpad for the ascender module on 3 December 2020, as turned out to be the case.
On 16 December 2020 at around 18:00 UTC, the roughly 300 kg (660 lb) return capsule performed a ballistic skip reentry, in effect bouncing off the atmosphere over the Arabian Sea before re-entry. The capsule, containing around 2 kg (4.4 lb) of drilled and scooped lunar material, landed in the grasslands of Siziwang Banner in the Ulanqab region of south central Inner Mongolia. Surveillance drones spotted the Returner capsule prior to its touchdown, and recovery vehicles located the capsule shortly afterwards.
The ~1,731 g (61.1 oz) of lunar samples collected by Chang'e-5 have enormous scientific meanings in terms of their abnormally young ages (<2.0 billion years old). At least, 27 fundamental questions can be answered by those samples on lunar chronology, petrogenesis, regional setting, geodynamic & thermal evolution, and regolith formation, especially, calibrating the lunar chronology function, constraining the lunar dynamo status, unraveling the deep mantle properties, and assessing the Procellarum KREEP Terrain structures.
Verifying the ages of those samples would provide data on the hypothesis that some areas of the Moon experienced late-stage volcanism, and compositional analysis could provide insights into the reasons behind it. Katherine Joy of the University of Manchester considers that the samples might represent some of the last lunar lava flows to have erupted. "If so, they not only tell us about the Moon's thermal history but these are also vital samples to help us calibrate the Moon's impact history". Dating this relatively young part of the Moon's surface would provide an additional calibration point for estimating the surface ages of other Solar System bodies. Wu Yanhua (吴艳华), deputy director of the China National Space Administration (CNSA) announced that the new samples will be shared with the UN and international partners for space research purposes.
Chang'e 5-T1 is an experimental robotic lunar mission that was launched on 23 October 2014 to conduct atmospheric re-entry tests on the capsule design that was planned to be used in the Chang'e 5 mission. Its service module, called DFH-3A, remained in orbit around the Earth before being relocated via Earth–Moon L2 to lunar orbit by 13 January 2015, where it is using its remaining 800 kg of fuel to test maneuvers critical to future lunar missions.
The European Space Agency (ESA) has supported the Chang'e 5 mission by providing tracking via ESA's Kourou station located in French Guiana. ESA has tracked the spacecraft during the launch and landing phases while providing on-call backup for China's ground stations throughout the mission. Data from the Kourou station has helped the mission control team at the Beijing Aerospace Flight Control Center to determine the spacecraft's health and orbit status. Chang'e 5 was returned to Earth on 16 December 2020. During the landing phase, ESA used its Maspalomas Station located in the Canary Islands and operated by the Instituto Nacional de Técnica Aeroespacial (INTA) in Spain, to support the tracking efforts.
Science journalist Bob McDonald discussed Chang'e 5 in comparison to the Soviet Luna programme, which involved Luna 15, Luna 16 and Luna 24 being sent to the Moon. Luna 15 attempted to grab a sample of lunar soil and return it to Earth before the American Apollo 11 astronauts Neil Armstrong and Buzz Aldrin got back in July 1969. It crashed during its landing attempt, hence losing the opportunity for a "propaganda coup". The Luna 16 mission successfully returned about 100 grams of lunar soil a year later and two other sample return missions succeeded in subsequent years, the most recent being Luna 24 in 1976. McDonald considers that China has entered another Moon race.
Bradley Perrett, Asia-Pacific Bureau Chief of Aviation Week Network, opined that the Moon race between the Soviet Union and the United States in the 1960s was driven by propaganda: a message to the world about their strength. Perrett noted that the Chang'e project was also driven by propaganda utility, but primarily for the internal audience; the reason that the Chinese government funded this mission was to show the Chinese people that it can be done.
Simon Sharwood, APAC Editor of The Register, observed that the mission was a success that went off without a hitch, with even the damage to the lander when the ascender lifted off not unexpected. Sharwood said that Chinese youths already have a lot to aspire given that China plans to build a space station and moon base in the future. Sharwood went on to say that such opportunities, however, will not be possible to all of them, based on his understanding of the relationship between technology and government in China.
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China's Mid-Autumn Day, a traditional occasion to celebrate family unity and harmony, is related to two Chinese tales. The first is the myth of Cháng'é, who flew to the moon, where she has dwelt ever since.