How China Conquered the Dark Side of the Moon

Ding Rui wrote . . . . . . . . .

China’s Chang’e-6 lunar probe has made history by returning to Earth with the first samples collected from the far side of the Moon — a groundbreaking feat that marks a new step forward for the country’s space program.

The spacecraft’s returner module touched down at the Siziwang Banner Landing Site in northern China’s Inner Mongolia Autonomous Region at 2:07 p.m. on Tuesday, delivering its precious cargo of around 2,000 grams of soil samples from the Moon’s dark side, China’s National Space Administration announced.

The mission — whose rocket is named after the Chinese moon goddess, Chang’e — is the latest stage in China’s lunar exploration program, which aims to land astronauts on the Moon by 2030 and build a research base on its South Pole.

Its success has brought that goal much closer to reality, collecting samples that stand to expand our knowledge of the lunar ecosystem as well as road-testing a number of new technologies that will be crucial for future missions.

What is the Chang’e-6 mission?

Chang’e-6 is the latest mission in China’s lunar exploration program, launched in 2004. The previous mission, Chang’e-5, saw a probe bring back 1,731 grams of soil samples from the near side of the Moon in December 2020.

The Chang’e-6 probe was originally intended to be a backup for Chang’e-5. But after the successful completion of that earlier mission, it was given the far more daunting task of collecting samples from the Moon’s far side.

No one had previously attempted such a feat — and for good reason. The far side of the Moon offers unique challenges for human exploration due to its rugged terrain and lack of direct view from Earth.

Because the Moon rotates around its axis at the same rate as it orbits Earth, the far side of the Moon is always facing away from us. This makes communicating with spacecraft on the far side difficult, as radio signals are blocked.

In addition, it’s also far more difficult to land probes on the far side of the Moon given that its surface, which faces outward toward the rest of the Solar System, is pockmarked by significantly more impact craters than the Moon’s near side.

“Due to the protective effect of Earth, the side of the Moon that always faces Earth has experienced fewer (asteroid) impacts, while the far side has experienced more,” Hou Xiyun, a professor of astronomy and space science at Nanjing University, told domestic media.

These factors mean that scientists still have limited knowledge about the nature of the Moon’s far side. Before Chang’e-6, a total of 10 probes had previously collected samples from the lunar surface, but they had all been taken from the near side.

The soil samples from Chang’e-6 could therefore provide enormous value for researchers looking to understand the lunar ecosystem and how it has developed over time.

“Through comparative studies in the laboratory, we can effectively reveal the different evolutionary processes that took place on the near and far sides of the Moon,” said Hou.

The mission is also a vital stepping stone toward China sending — and eventually settling — astronauts to the Moon. Now that Chang’e-6 has retrieved samples from the far side, the goal is to send a Chang’e-7 mission to the Moon’s South Pole.

Chang’e-7 is designed to search the lunar South Pole for traces of ice — which is considered key to supporting a long-term presence on the Moon — and then work with Chang’e-8 to start work on building a lunar base.

How did the mission work?

Chang’e-6 had a similar design to Chang’e-5, with a spacecraft made up of four main modules: an orbiter that propels the craft to and from lunar orbit; a lander that descends to the lunar surface and conducts the sampling operations; an ascender attached to the lander, which blasts off from the lunar surface and reconnects with the orbiter; and a returner that descends back through the Earth’s atmosphere.

But landing on the far side of the Moon presented myriad new technical challenges — the greatest of which was the difficulty of communicating with ground control back on Earth.

“Landing the probe on the far side of the Moon is currently difficult to pull off as a fully autonomous process; it still requires the support of a telemetry and command system,” said Hou.

To solve this problem, China launched a satellite — Queqiao-2 — into lunar orbit back in March, which was used to relay communications from Earth around to the dark side of the Moon. This allowed ground control to keep track of Chang’e-6 and control its landing, sample collection, and ascent back into lunar orbit.

But even with the relay satellite, things were far from simple. The Moon still partially blocked signals at certain points in its orbit, meaning that Chang’e-6 had to complete its entire mission in just 14 hours — several hours less than its predecessor, Chang’e-5.

With Chang’e-6 needing to collect samples from several locations and depths on the far side of the Moon to provide scientists with a comprehensive picture of the environment, the ground control team faced a daunting challenge.

“While each individual task may not be overly difficult, compressing the same workload into a very short timeframe poses a significant challenge in itself,” Jin Shengyi, an expert from the China Aerospace Science and Technology Corporation, told state broadcaster station CCTV.

To speed things up, the team upgraded the technology used in the probe, allowing it to execute more tasks autonomously and making it less dependent on maintaining a stable communication channel with Earth.

“We have also used new techniques to speed up the operation of the mechanical arm and optimized the route taken by the lander to compress the time needed to complete the sampling,” Jin said.

Fortunately, the 53-day mission proceeded smoothly. Chang’e-6 launched on May 3 and touched down successfully on June 2 in an impact crater on the Moon’s far side known as the Apollo Basin.

The Apollo Basin is located inside the even larger South Pole-Aitken Basin — the oldest and largest impact crater on the Moon’s surface, with a surface area equivalent to around half of China. The Apollo Basin landing site was chosen because it’s flatter than most other areas in that region of the lunar surface.

After completing its sampling, Chang’e-6 rocketed back toward the Earth’s orbit at a speed of nearly 11.2 kilometers per second — 30 times the speed of sound — before the returner descended back through the atmosphere, deploying parachutes twice to ensure a safe landing.

The returner and its samples — which Chinese media have been jokingly referring to as “Moon specialty products” — will now be processed by ground crews in Inner Mongolia before being airlifted to Beijing.

Source : Sixth Tone

China’s Moon Mission Leaves Patriotic Graffiti on Lunar Surface

Bruce Einhorn and Wenshan Luo wrote . . . . . . . . .

A Chinese spacecraft has lifted off from the far side of the moon but not before marking the historic visit with a bit of patriotic graffiti.

Chang’e-6, the first sample-retrieval mission to the far side of the moon, blasted off on its journey back to Earth Tuesday after leaving a mark on the lunar surface that resembled the Chinese character ‘Zhong,’ state media reported.

Zhong is the first part of Zhongguo, the Chinese-language name for China. It can also mean center in Chinese.

“There is a Chinese character on the back of the moon,” broadcaster CCTV posted on Weibo, the popular Chinese social media site. “After collecting samples, the moon’s surface now shows a ‘Zhong’ character.”

For people who don’t read Chinese, the shape might seem more like a plus sign, but that didn’t deter many social media users in China from expressing pride in the country leaving its mark on the moon.

The moon mark was one of the top trending items on Weibo on Tuesday.

“The first human character appeared on the moon: It’s the ‘Zhong’ in Zhongguo,” wrote one fan.

China isn’t the first country to leave its mark on the lunar surface.

During their trips to the moon in the late 1960s and early 1970s, US astronauts left everything from equipment and trash to American flags and a photo of astronaut Charles Duke’s family.

Alan Shepard, the first American in space when he flew on a Mercury spacecraft in 1961, left two golf balls that he hit with a six-iron during the Apollo 14 mission in 1971.

The last Apollo astronaut on the moon, Gene Cernan, in December 1972 “left his daughter’s initials behind in the lunar dust,” according to Space Center Houston, the official visitor center for NASA’s Johnson Space Center and an affiliate of the Smithsonian.

Source : BNN Bloomberg

China Lands on Moon’s Far Side in Historic Sample-retrieval Mission

Liz Lee, Joey Roulette, Joe Brock and Eduardo Baptista wrote . . . . . . . . .

China landed an uncrewed spacecraft on the far side of the moon on Sunday, overcoming a key hurdle in its landmark mission to retrieve the world’s first rock and soil samples from the dark lunar hemisphere.

The landing elevates China’s space power status in a global rush to the moon, where countries including the United States are hoping to exploit lunar minerals to sustain long-term astronaut missions and moon bases within the next decade.

The Chang’e-6 craft, equipped with an array of tools and its own launcher, touched down in a gigantic impact crater called the South Pole-Aitken Basin on the moon’s space-facing side at 6:23 a.m. Beijing time (2223 GMT), the China National Space Administration said.

The mission “involves many engineering innovations, high risks and great difficulty”, the agency said in a statement, opens new tab on its website. “The payloads carried by the Chang’e-6 lander will work as planned and carry out scientific exploration missions.”

The successful mission is China’s second on the far side of the moon, a region no other country has reached. The side of the moon perpetually facing away from the Earth is dotted with deep and dark craters, making communications and robotic landing operations more challenging.

Given these challenges, lunar and space experts involved in the Chang’e-6 mission described the landing phase as a moment where the chance of failure is the highest.

“Landing on the far side of the moon is very difficult because you don’t have line-of-sight communications, you’re relying on a lot of links in the chain to control what is going on, or you have to automate what is going on,” said Neil Melville-Kenney, a technical officer at the European Space Agency working with China on one of the Chang’e-6 payloads.

“Automation is very difficult especially at high latitudes because you have long shadows which can be very confusing for landers,” Melville added.

The Chang’e-6 probe launched on May 3 on China’s Long March 5 rocket from the Wenchang Satellite Launch Center on the southern island of Hainan, reaching the lunar vicinity roughly a week later before tightening its orbit in preparation for a landing.

Chang’e-6 marks the world’s third lunar landing this year: Japan’s SLIM lander touched down in January, followed the next month by a lander from U.S. startup Intuitive Machines.

The other countries that have sent spacecraft to Earth’s nearest neighbour are the then-Soviet Union and India. The United States is the only country to have landed humans on the moon, starting in 1969.

SAMPLING THE MOON

Using a scoop and drill, the Chang’e-6 lander will aim to collect 2 kg (4.4 pounds) of lunar material over two days and bring it back to Earth.

The samples will be transferred to a rocket booster atop the lander, which will launch back into space, tag up with another spacecraft in lunar orbit and return, with a landing in China’s Inner Mongolia region expected around June 25.

If all goes as planned, the mission will provide China with a pristine record of the moon’s 4.5 billion-year history and yield new clues on the solar system’s formation. It will also allow for an unprecedented comparison between the dark, unexplored region with the moon’s better understood Earth-facing side.

A simulation lab for the Chang’e-6 probe will develop and verify sampling strategies and equipment control procedures, China’s official Xinhua news agency said. It will use a full-scale replica of the sampling area based on exploration results on the environment, rock distribution and lunar soil conditions around the landing site.

China’s lunar strategy includes its first astronaut landing around 2030 in a programme that counts Russia as a partner. In 2020 China conducted its first lunar sample return mission with Chang’e-5, retrieving samples from the moon’s nearer side.

The U.S. Artemis programme envisions a crewed moon landing by late 2026 or later. NASA has partnered with space agencies including those of Canada, Europe and Japan, whose astronauts will join U.S. crews on an Artemis mission.

Artemis relies heavily on private companies, including Elon Musk’s SpaceX, whose Starship rocket aims this decade to attempt the first astronaut landing since NASA’s final Apollo mission in 1972.

On Saturday Japanese billionaire Yusaku Maezawa cancelled a private mission around the moon he had paid for, which was to have used SpaceX’s Starship, citing schedule uncertainties in the rocket’s development.

Boeing and NASA postponed the company’s first crewed launch of Starliner, a long-delayed capsule meant to become the second U.S. space taxi to low-Earth orbit.

Source : Reuters

Chart: Successful Pinpoint Landing of Japanese Lunar Probe

The Japan Aerospace Exploration Agency (JAXA) announced on the 25th that its lunar probe SLIM successfully made a “pinpoint landing” with an error of less than 100 meters from its target location. They also released an image of Slim created by two small robots working together. All of these results are world firsts, and will be a strength for Japan in future resource exploration.

The ultra-compact robot “Reb 2 (commonly known as SORA-Q)” weighs about 250 grams and is about the size of a baseball.

Source : Nikkei

Infographic: All Attempted and Successful Moon Landings

See large image . . . . . .

Source : Visual Capitalist

China Reveals How It Plans to Put Astronauts on the Moon by 2030

Jessie Yeung and Candice Zhu wrote . . . . . . . . .

Chinese officials on Wednesday unveiled new details about their plans for a manned lunar mission, as China attempts to become only the second nation to put citizens on the moon.

Zhang Hailian, deputy chief engineer with the China Manned Space Agency (CMSA), revealed the preliminary plan at an aerospace summit in the city of Wuhan on Wednesday, according to state-run news agency Xinhua.

The mission, expected to take place before 2030, is part of a project to establish a lunar research station. It will investigate how best to build the facility, and carry out moon exploration tasks and other experiments, Zhang said.

Two launch vehicles will send a moon surface lander and manned spacecraft into lunar orbit, before they dock with each other, according to state-run Global Times. After docking, the Chinese astronauts on board the spacecraft will enter the lander, which is used to descend to the moon’s surface.

While on the moon, they will collect samples and carry out “scientific exploration,” before leaving on the lander and reuniting with the spacecraft waiting in orbit – which will take them home to Earth, Global Times reported.

To prepare for the mission, Chinese researchers are busy developing all the necessary equipment including moon suits, manned lunar rovers, manned spaceships and moon landers, Xinhua reported.

The state media reports did not say how many astronauts China plans to send to the moon.

The lunar mission is the latest development in China’s push to advance its space program, which has seen several breakthrough moments in recent years.

China was late to the space race – it didn’t send its first satellite into orbit until 1970, by which time the United States had already landed an astronaut on the moon – but Beijing has been catching up fast.

In 2013, China successfully landed a rover on the moon, becoming only the third country to do so. At the time, Chinese leader Xi Jinping said “the space dream is part of the dream to make China stronger.”

Under Xi’s leadership, China has spent billions on its ambitious space program. While there are no official public figures on Beijing’s investment in space exploration, consulting firm Euroconsult estimated it to be about $5.8 billion in 2019.

That year, China sent a rover to the far side of the moon – a historic first. Then in 2020, it became only the third country to successfully collect rock samples from the moon.

China has also spent the past few years building its own Tiangong space station, which was completed in November. The station is only the second operational orbital outpost, alongside the International Space Station (ISS) – which Chinese astronauts have long been excluded from due to US political objections and legislative restrictions.

But the ISS is expected to end operations in 2030 – which could leave Tiangong the only outpost left. China has sought to open up its station to collaboration with international partners, including by hosting experiments from other countries.

Source : CNN

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Read also at Global Times

China to send taikonauts to moon for lunar research, technology verification before 2030 using two rockets: CMSA official . . . . .

香港团队研发表取采样装置 助力嫦娥五号月球“挖土”成功

记者: 朱宇轩、万后德 . . . . . . . . .

　　中国探月工程嫦娥五号探测器日前成功落月并完成核心关键任务——月面自动采样封装。在中国首次月面采样返回的探测任务中，香港理工大学（以下简称“理大”）科研团队研发的表取采样装置助力嫦娥五号在月球表面“挖土”成功，闪耀香港科研团队在国家重要科研项目中的又一次高光。

　　理大8日介绍，嫦娥五号采样方式包括钻具钻取和机械臂表取，理大科研团队承担的正是表取采样系统的研发。表取采样指的是利用机械臂在月面进行多点采样，机械臂由中国空间技术研究院制造，采样执行装置则由理大工业及系统工程学系讲座教授兼副系主任容启亮率领约20多名香港科研人员研发制造。

　　容启亮及其团队研发的表取采样执行装置附着在嫦娥五号的着陆器上，整套装置由超过400件工件组合而成，包括采样器甲、采样器乙、初级封装装置和近摄相机。采样器甲和采样器乙分别用来挖取松散和黏性的月球土壤，初级封装装置是表取样本的暂存器，近摄相机则发挥识别样本和视像导航等作用。

　　容启亮向新华社记者介绍，纵观全球探月历程，嫦娥五号采样任务实现了采样方式和采样地点的两大突破，对科研发展无疑有着至关重要的作用。他表示，嫦娥五号创造性地完成了月面自动表取采样并封装。在采样地点上，嫦娥五号没有选择曾经被采样的地点，而是开拓了一处受风化影响较小、月壤没有被采集过的“处女地”。

　　从2012年完成原理样机研发到向国家交付正样件，再到嫦娥五号成功完成表取采样，容启亮形容“这些年走过的每一步都是挑战”。单以表取采样执行装置为例，这一装置是在月球面向太阳的地方运作，月面温度高达110摄氏度，所以容启亮团队设计的系统必须能够克服极高温、宇宙射线等极端环境并保持样本稳定。

　　容启亮十分感激国家授予理大科研团队表取采样这一关键装置的研发任务。他说，香港是一座开放型的城市，科学家有机会接触各种前沿的科学理念，但仅仅有好的想法、没有雄厚的科研实力是远远不够的，国家给予香港科研人才承担重大科研项目的机会，鼓励香港科研人员融入国家发展，更是促进了香港在国家科研发展中承担重要角色。

　　展望未来，容启亮表示还将继续与海内外科研机构深化合作，“多方面的合作能够催生新思维，开阔科研人员的眼界”。

Source : 新华网

月球上升“织物版”五星红旗，背后是硬科技支撑

作者: 张田勘 . . . . . . . . .

嫦娥五号登月堪称一部现实版的大片，这部惊心动魄的大片背后，是全方位硬科技和软科技的支撑。

　　一张“五星红旗亮相月球”的图片，刷屏了网络。

　　据新京报报道，12月3日23时10分，嫦娥五号上升器月面点火，3000牛发动机工作约6分钟后，顺利将携带月壤的上升器送入到预定环月轨道，成功实现我国首次地外天体起飞。而在点火起飞前，着陆器上升器组合体携带的一面“织物版”五星红旗成功展开。

　　月球这抹“中国红”，必将记入史册

　　这是我国在月球表面首次实现国旗的“独立展示”，也是继嫦娥三号、四号任务后国旗又一次在月球亮相。相比嫦娥三号、四号以及玉兔月球车上喷涂的国旗，嫦娥五号的国旗是一面真正的旗帜。据回传影像显示，五星红旗在阳光照耀下，“中国红”格外鲜艳。

　　嫦娥五号登月堪称一部现实版的大片，这部惊心动魄的大片背后是全方位硬科技和软科技的支撑。此前，美国成功登陆月球并插上星条旗，成为人类航空航天史上经典一幕。如今，月球上的这抹“中国红”也必将记入史册。

　　事实上，考虑到月球上没有风、表面有正负150摄氏度的温差、电磁辐射等独特的天文地理环境，在月球上独立展示国旗看似简单，困难却极大。但中国技术也独具特色、自成系统。

　　比如，经过1年多试验，研究人员通过高低温试验才发现，卷轴形式展开的国旗较平整，不会出现褶皱等情况。要解决的，还有国旗的织物材料和是否褪色等难题。反复试验后，研究人员最终选出二三十种纤维材料，再进行热匹配性、耐高低温、防静电、防月球尘埃等物理试验，最终才找到一种合适的新型复合材料。

　　此外，中国的国旗采用的是杆系结构，使用二级杆的方式来呈现，是航天系统里比较成熟的技术。要考虑的是支架系统承受冷热交变、空间辐照、极低真空等恶劣环境考验，任何不当都可能造成国旗无法展开，如发生冷焊（两块接触金属在太空极低真空环境下会粘连在一起）。为此，需对系统所有机构和关键位置都进行防冷焊处理。

　　这些，都无不体现了科研人员的智慧、科技的强大力量和魅力。

　　首次地外天体起飞，技术难度有点高

　　值得一说的是，嫦娥五号实现了我国首次地外天体起飞，这殊为不易——航天器在地外天体表面起飞，是一项极为重要的航天技术，此前只有美国和苏联（俄罗斯）两国能完成。能掌握这样更高难度的技术，也展示了中国在空间技术上的诸多突破。

　　要在月球表面升空，需要解决的是升空的动力和上升时的姿势。月亮引力只有地球的1/6，实际需要的动能会更小。这难度虽不大，但航天器的垂直上升、姿态调整和轨道射入都需精确计算和控制。升空后，也还要经历垂直上升、姿态调整和轨道射入三个阶段，才能进入预定轨道。

　　上升器在起飞之初的一小段距离内不能进行姿态调整，此后要根据之前收到的参数进行调整，才能竖直上升。到达一定高度后，还要在GNC系统的统一指令下，让主发动机和姿态控制发动机共同整合，使上升器按既定程序拐弯，并以适宜角度转入轨道入射段。

　　上升器从月面起飞约飞行6分钟、250千米后，再进入与轨道器和返回器组合体交会对接的初始轨道。上升器启动交会对接程序，还要飞行几圈，完成4次远程导引后，才能实施交会对接，把采集到的约2千克月壤转移到返回器。

　　一言以蔽之，嫦娥五号登月以及未来几天的降落地面，是中国科研人员一系列高难技术支撑的结果，每一个环节都离不开精心设计和技术创新。而首次做到地外天体表面起飞，证明中国已跻身于世界航天俱乐部第一梯队，也为未来进一步探测深空和载人到达月球创造了条件。路漫漫其修远兮，但迈出这一大步，无疑会让我们离“航天强国梦”更近。

Source : 新华网

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Read also:

嫦娥五号启程回地球 出发前在月表展示国旗 . . . . .

AP News – Chinese spacecraft carrying lunar rocks lifts off from moon . . . . .

嫦娥五号传回着陆影像

Source : 新华社

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