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  • Post published:November 24, 2020
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Chang’e 5, China ambitious mission to bring back samples from the Moon
新华社照片,北京,2019年1月11日 嫦娥四号任务圆满成功 这是玉兔二号巡视器全景相机对嫦娥四号着陆器成像。 1月11日下午,嫦娥四号着陆器与玉兔二号巡视器工作正常,在“鹊桥”中继星支持下顺利完成互拍,地面接收图像清晰完好,中外科学载荷工作正常,探测数据有效下传,搭载科学实验项目顺利开展,达到工程既定目标,标志着嫦娥四号任务圆满成功。至此,中国探月工程取得“五战五捷”。 新华社发(国家航天局供图)

Today, China successfully launched its most ambitious mission to the Moon to date, called Chang’e 5 — a mission designed to bring a handful of moonstones backs to Earth before the end of the year. If successful, this will be the first time in nearly half a century that dirt from the Moon is returned to Earth, and the first time China has taken material from another world.

The mission is the latest in a long line of lunar missions China has carried out over the past decade. In 2013, the country made its first soft landing on the Moon with Chang’e 3, making China one of only three countries to place spacecraft on the lunar surface. Then in December 2018, China launched Chang’e 4 and succeeded in placing landers and explorers on the far side of the Moon in early 2019 — a feat no other country has achieved.

Now with Chang’e 5, China plans to bring back Moon samples. So far, only two countries — the United States and the former Soviet Union — have ever returned material from the Moon. Chang’e 5 could soon be next, and the lessons learned from this mission could put the country on the right track for more complex flights to the Moon in the future.

“This is one thing that the Chinese space program is very good at,” Andrew Jones, a freelance reporter specializing in China’s space program, told in a statement. “They set incremental targets and goals, and they build on what they’ve achieved and make more ambitious targets.”

But first, things have to go right, and Chang’e 5 is perhaps the most complex mission China has ever launched. For one thing, the mission is pretty tough, with all the hardware needed for a round-trip lunar flight weighing in at about 8.2 metric tons, or about 18,000 pounds. To carry Chang’e 5 on a journey to the Moon, China used its most powerful rocket, the Long March 5. The rocket took off from the Wenchang Spacecraft Launch Site located in southern China.

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The Long March 5 lofted a total of four robotic spacecraft for Chang’e 5, which will work together to bring between 2 to 4 kilograms of the lunar sample back to Earth, according to Jones. The quartet starts off its journey together, traveling to the Moon in a big pack. One of the four includes a service spacecraft that will help provide solar power and propel the group to the Moon. After entering the Moon’s orbit, two of the spacecraft — a lander and a vehicle to take off from the lander — will break away and descend to the surface. The lander will then use instruments to drill into the Moon, passing along the material it collects to the ascent vehicle sitting on top.

That ascent vehicle will then act as a mini-rocket, taking off from the Moon and meeting up with the hardware still in lunar orbit. Once it docks with the service spacecraft, the lunar sample will pass into the fourth spacecraft — a capsule designed to land back on Earth. The trio will then leave lunar orbit and head back to Earth. Eventually, the return capsule will break away with its precious materials inside. Since it will be coming in so fast from the Moon, the capsule will actually bounce off the Earth’s atmosphere once before diving toward the planet and eventually landing in Inner Mongolia.

All in all, it should be a quick mission, lasting just 23 days or so from launch to landing of the lunar material, Jones says. That’s because Chang’e 5 is not designed to survive the harsh lunar night, a two-week period that occurs every month when part of the Moon’s surface is plunged into darkness and temperatures can drop well below -208 degrees Fahrenheit (-130 degrees Celsius). To survive such an extreme environment, the surface spacecraft would need to be equipped with special heating instruments — such as radioisotope generators that radioactively decay over time and generate warmth. Previous Chang’e missions included these generators to survive the lunar night, but such materials are missing on Chang’e 5 since this is designed to be a quick “grab and go” mission.

That means in less than a month, China could bring back the first samples of the Moon returned to Earth since the Cold War era. US astronauts famously brought back lunar rocks collected during the Apollo missions in the 1960s and ’70s, while the former Soviet Union performed a handful of successful lunar sample return missions in the 1970s. In fact, the last time lunar rocks came back to Earth occurred in 1976 with the Soviet Union’s Luna 24 robotic probe.

Chang’e 5 is targeting a particularly enticing part of the Moon called Oceanus Procellarum. This unexplored area has relatively few craters on its surface compared to other parts of the Moon. One theory is that volcanic activity may have occurred in this area late in the Moon’s life, smoothing away craters that were there before. Getting samples from this region could provide scientists with a better understanding of when this volcanic activity might have occurred, providing a better snapshot of how the Moon formed and evolved.

“It’s a big deal for the science community in China, and also the data will be keenly followed by scientists internationally,” Jones said.

The complexity of Chang’e 5 is also a deliberate choice for China, according to Jones, as it will allow the country to test out how to rendezvous and dock spacecraft in orbit around the Moon. China could have opted for the ascent vehicle to take the lunar samples all the way back to Earth. But Jones notes that the meetup in lunar orbit is meant to test out capabilities needed on future missions. A mission designed to return samples from Mars could certainly draw from Chang’e 5. But it’s also important to note that this mission is very similar in its flight profile to that of NASA’s Apollo missions, which used similar techniques for putting people on the Moon.

“This is much more of an Apollo kind of mission profile than it was for the Soviet robotic lunar sample return,” replies Jones. “So the idea is that they’re playing out and practicing for future crewed missions to the Moon.”