Chang’e-4 is second spacecraft in Chinese mission to land on far side of the moon

China’s lunar lander Chang’e-4 has successfully entered orbit around the moon.

After a voyage of 240,000 miles (385,000km) that lasted 110 hours, the spacecraft fired its retrorockets on 12 December while just 80 miles above the lunar surface. This placed it in a stable elliptical orbit, where it will stay until the landing attempt, which is expected next month.

Chang’e-4 was launched on 7 December atop a Long March-3B rocket from Xichang Satellite Launch Centre in China’s Sichuan province.

Spacewatch: China readies for part one of mission to far side of the moon Read more

It is the second spacecraft in the China National Space Administration’s (CNSA) mission to attempt the first landing on the far side of the moon.

The first spacecraft, a communications relay satellite called Queqiao, launched on 20 May and is now stationed in its operational orbit about 40,000 miles beyond the moon.

A relay satellite is needed because once the lander is on the far side of the moon, it will not be in sight of Earth.

A date for the landing attempt has not yet been announced but it is likely to take place in early January after mission controllers have tested all systems.

The spacecraft carries experiments and instruments from a number of countries including Germany, the Netherlands, Saudi Arabia and Sweden. </s> A Chinese lander destined for the far side of the Moon - the side that always faces away from the Earth - has now entered lunar orbit, Space News reports.

Early Wednesday morning, the spacecraft carrying the Chang'e-4 lander completed its journey from Earth, which took nearly five days, and settled into an elliptical orbit around the Moon.

If the mission is successful, Chang'e-4 will be the first-ever lander to explore the so-called "dark side of the Moon".

It'll rove the lunar surface, examine the Moon's composition, and even dabble in amateur gardening with a small pod that'll grow seeds and silkworm larvae.

To communicate with the Earth, Chang'e-4 will bounce signals off a relay satellite launched earlier this year.

Chinese officials haven't announced a firm date or location for the craft's landing, but it's expected to touch down in early January 2019, probably in the spacious Von Kármán crater.

China is already planning Chang'e-5, the mission to come after Chang'e-4. If all goes according to plan, that will be China's first Moon mission to return samples back to Earth and it'll launch in late 2019.

This article was first published on Futurity and is republished here under a CC BY 4.0 license. Read the original article. </s> Humans have landed a spacecraft on the far side of the moon for the first time in history.

China's Chang'e 4 spacecraft achieved the milestone on Jan. 3, with the country's space agency landing its lunar probe in Von Kármán crater on the moon's mysterious far side. Official word was provided at 8 p.m. PT by Chinese State Media service CCTV.

Launched on Dec. 7, the Chang'e 4 craft contains both a lunar lander and a six-wheeled rover. The spacecraft entered lunar orbit on Dec. 12 before preparations for landing nudged the spacecraft into an elliptical lunar orbit, getting as close as 15 kilometres (around 9 miles) to the surface.

Unlike NASA's history-making mission to Mars in November and the agency's flyby of the mysterious Kuiper Belt Object 2014 MU69 on New Year's Day, China's landmark landing wasn't televised. Social media accounts on Chinese giant Weibo reported that the lunar probe touched down at around 6:26 p.m. PT but confirmation of the reports was hard to come by. After tweets by Chinese State-owned media outlets China Daily and China Global Television Network made their way online, the Twittersphere was abuzz... but the tweets were quickly deleted.

According to Andrew Jones, a journalist reporting on the Chinese space program, Chang'e 4's descent required "laser ranging and optical cameras for navigation, velocity and coarse hazard avoidance." Practically, this meant Chang'e 4 was on its own as it descended to the surface with its important scientific payload, on a side of the moon marked by rugged terrain.

NASA astronauts Neil Armstrong and Buzz Aldrin set foot on the moon almost 50 years ago, but navigating to the far side poses a unique communications challenge. Sometimes known as the "dark side" of the moon, even though it does receive sunlight, the far side never faces the Earth because of tidal locking. That means budding human (or robot) explorers have to find a way to establish and maintain radio contact.

To communicate with the Chang'e 4 mission on the moon's surface, the Chinese space agency launched the Queqiao relay satellite into a halo orbit over the dark side of the moon in May. The satellite overcomes the communications challenge, allowing the lander and rover to phone home, via relay, and send scientific data back.

Both the rover and the lander are equipped with a suite of instruments that will allow the Chinese space agency to study the geology of Von Kármán crater, including three cameras. The ancient crater, part of the 13 kilometre deep South Pole-Aitken (SPA) Basin, is believed to hold material kicked up from deep within the lunar soil due to an impact early on in the Moon's life, providing new insights on what makes up its interior. The lander also carries seeds and silkworm eggs within a sealed container and will examine whether the two lifeforms can thrive on the moon.

Other instruments, developed by Swedish and German engineers, will allow the lunar robots to better study solar wind, charged particles that burst forth from the sun's atmosphere. Payloads were also provided by partners in the Netherlands and Saudi Arabia.

The last lander on the moon was Chang'e 4's predecessor, Chang'e 3, which soft-landed in a crater known as the Mare Imbrium in December 2013. In January 2014, the rover underwent a mechanical control abnormality and ceased to transmit data in March 2015. However, the lander remains on the near side of the moon.

The moon really is the place to be in 2019, with various international space agencies ready to explore Earth's only natural satellite. Chang'e 4's mission is slated to last a year, but a subsequent lunar exploration mission -- Chang'e 5 -- is scheduled to launch toward the end of the year. If successful, it would be the first mission to the moon to return samples since Luna 24 in 1976.

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Taking It to Extremes: Mix insane situations -- erupting volcanoes, nuclear meltdowns, 30-foot waves -- with everyday tech. Here's what happens. </s> China’s Chang’e-4 lunar mission, the first-ever soft-landing endeavor on the lunar farside, launched successfully on 8 December at 02:23 Beijing time (7 December at 18:23 UTC) via a Long March 3B rocket from Xichang Satellite Launch Center. The launch carried a lander and a rover toward the Moon. On 12 December at 8:45 Beijing time (16:45 UTC), the spacecraft arrived in lunar orbit, preparing for a landing in early January.

The launch placed Chang’e-4 directly into a 200- by 420,000-kilometer Earth-Moon transfer orbit, similar to the paths of Chang’e-2, -3 and Queqiao. (Chang’e-1 orbited Earth 3 times before moving to an Earth-Moon transfer orbit). This type of transfer orbit typically takes 4 to 5 days, and navigators plan 2 or 3 trajectory correction maneuvers (TCMs) to adjust the path. Actually, Chang’e-4 required only one TCM:
• The first TCM, which was planned for 8 December at about 19:42 Beijing time (11:42 UTC), was canceled because the trajectory was deemed accurate enough.
• The second TCM was carried out on 9 December at 16:42 Beijing time December 9 (8:42 UTC).
• The third TCM, which was planned for about 24 hours ahead of the braking maneuver (11 December at about 16:42 Beijing time or 8:42 UTC), was also canceled because the second maneuver had placed the vehicle on an accurate enough trajectory.

Canceling maneuvers leaves reserve fuel on the spacecraft for the landing phase.

During the Earth-Moon transfer phase, amateur radio astronomer Scott Tilley tracked Chang’e-4 several times. For example, he told us Chang’e-4 was about 366,000 kilometers away from Earth on 11 December at about 05:40 Beijing time (10 December at 21:40 UTC) and was on its expected orbit. (He is also keeping tabs on Chang'e-5 T1, still communicating with Earth from a stable lunar orbit.)

Today, the China National Space Agency (CNSA) announced successful lunar orbit insertion via Xinhua news. The command for the braking maneuver burn was issued on 12 December at 16:39 Beijing time (08:39 UTC), and Chang’e-4 successfully inserted into lunar orbit with a perilune of about 100 kilometers at 16:45 (8:45 UTC).

Now that Chang’e-4 has already entered lunar orbit, why is it waiting 20 more days to land? There are probably several reasons.

Engineers have work yet to do to prepare for landing. They will test instruments, test the relay link with Queqiao, and so on. They may need to adjust the orbit in order to better target the landing, which must be more precise on the rugged farside than Chang’e-3’s in the flat nearside maria.

They also have to wait for the Sun to rise in the landing region. The far side of the Moon is not the “dark side”, it has daytime and nighttime as we do. The difference is one lunar day is much longer, with about 14 earth days of daytime and about 14 earth days of nighttime.

You can check to see where it is day and night on the Moon easily at the Lunar Reconnaissance Orbiter QuickMap website. Open up the Layers tab, choose “Overlays,” and then tap the “Sunlit Region” button.

Here is the day and night region of lunar farside (left) and nearside (right) on 12 December at about 17:00 Beijing time (9:00 UTC). You can see that night is about to fall across the South Pole-Aiken Basin region, the target region of Chang’e-4’s landing.

The Sun will rise again around the New Year, so Chang’e-4 will probably land in the first few days of January 2019. The slow pace of sunrise and sunset will control the activity of Chang’e-4’s rover. Recall that the Chang’e-3 rover, Yutu, could not work at night due to the cold environment. It first roved onto the surface on 15 December 2013 and stopped on 24 December as the sun set. It resumed activity on 11 January 2014 when daytime returned.

The 180-kilometer-diameter crater Von Kármán (centered at 44.8°S 175.9°E) inside the South Pole-Aiken Basin seems to be the most likely landing site, although there seem to be other potential sites. But no matter where the exact location is, one thing is for sure: the topography of the landing site is much more rugged and complex than the flat Mare Imbrium, the landing site of Chang’e-3.

According to the reports on Chinese television, the landing of Chang’e-4 is much more challenging and risky than Chang’e-3 because of the difficult topography. The lander has to autonomously assess its altitude and velocity relative to the surface in order to land safely, which is why landing regions that are flat over a broad area are preferred.

Therefore, the landing strategy of Chang’e-4 will be a little different from Chang’e-3. Chang’e-4’s approach to landing will be much steeper, compared to the shallow landing trajectory of Chang’e-3.

Compared to launch and orbit insertion, landing will be the real challenge for Chang’e-4. Hope everything goes well! </s> CHINA’S Chang’e-4 probe decelerated and entered a lunar orbit yesterday, completing a vital step on its way to making the first soft landing on the far side of the moon.

After traveling 110 hours from the Earth, an engine on the probe was ignited when it was 129km above the surface of the moon, said the China National Space Administration. The probe then slowed, and entered an elliptical lunar orbit at 100km above the surface. The probe, including a lander and a rover, was launched by a Long March-3B carrier rocket last Saturday from the Xichang Satellite Launch Center.

The control center will choose a proper time to land after testing communications.

The Chang’e-4 mission will be a key step in revealing the mysterious far side of the moon.

The scientific tasks of Chang’e-4 include low-frequency radio astronomical observation, surveying the terrain and landforms, detecting the mineral composition and shallow lunar surface structure, and measuring neutron radiation and neutral atoms.

China has promoted international cooperation, with four scientific payloads of Chang’e-4 developed by scientists from the Netherlands, Germany, Sweden and Saudi Arabia. </s> China plans to launch a spacecraft to the far side of the moon this month. The Chang’e-4 spacecraft is scheduled to take off from Xichang Satellite Launch Center in Sichuan on December 8 carrying a lander and rover, which will touch down on the lunar surface. No spacecraft has ever touched down on the surface of the moon’s far side.

The mission is to explore and study the crater-marked far side of the moon, conducting the first radio astronomy experiments from that region, reports Scientific American.

Chang’e-4 is the China National Space Administration’s (CNSA) latest move in its lunar aspirations. In 2013, Chang’e-3 performed a “soft” landing on the surface. In the years that followed, CNAS announced its plan to build a moon base, launching a satellite to relay communications from the lander on the lunar surface to Earth, circumventing the moon’s mass.

If the touchdown is successful for the Chang’e-4 rover, it will be tasked with mapping the area around its landing site. Equipped with a ground-penetrating radar, the rover will measure the subsurface layers. A near and infrared spectrometer will allow it to measure the mineral makeup of the lunar soil. These measurements may help geologists better understand the geological dynamics of the moon’s evolution.

The CNSA has not made Chang’e-4’s landing site public, though Zongcheng Ling, a planetary scientist at Shandong University and member of the mission team, told Scientific American that the most probable location is Von Kármán, a more than 115-mile wide crater.

Part of Chang’e-4 mission is in preparation for future crewed missions and the CNAS’s desired moon base. Among its experiments will be one to study whether certain seeds sprout and photosynthesize in a controlled environment on the moon’s low-gravity surface.

“When we take the step towards long-term human habitation on the Moon or Mars, we will need greenhouse facilities to support us, and will need to live in something like a biosphere,” Anna-Lisa Paul, a horticultural scientist at the University of Florida, told Scientific American.

This specific experiment will aim to verify studies conducted no the International Space Station, which determined that potato and thale-cress grow normally in controlled low-gravity environments but not in environments with gravity as low as the moon’s.

The CNAS has another mission, Chang’e-5, slated to launch in 2019. Chang’e-5’s mission will be to bring back samples collected by the rover. </s> China is set to launch the world's first mission to the far side of the moon. Its Chang'e 4 robotic spacecraft is scheduled to lift off Friday at around 1:30 p.m. ET (2:30 a.m. in China, on Saturday, Dec. 8), Space.com reported.

The spacecraft will launch atop a Long March 3B rocket from the Xichang Satellite Launch Center in the southwestern province of Sichuan. Plans call for Chang'e 4, which carries both a lander and a lunar rover, to touch down on the moon in early January.

"Anything we land on the moon is significant, but this one is especially so," David Paige, a planetary scientist at the University of California, Los Angeles, said of the mission.

It is a successor to China's Chang'e 3 mission, which successfully placed a lander and rover on the moon's Earth-facing side in 2013.

Chang'e 4's planned landing site lies within the South Pole-Aitken basin. The sprawling basin, which is 8 miles deep and more than 1,500 miles across, is one of the moon's largest and oldest impact craters.

"This crater has the potential to tell us something about the creation of the Earth and moon system — how the moon formed, as well as how the early solar system evolved," Paige said. "Understanding exactly when this basin formed and how it relates to other lunar impact basins is key."

The lander and rover are each equipped with cameras. The rover also sports a ground-penetrating radar instrument designed to help scientists gain an understanding of the moon’s geological history as well as a spectrometer to study its chemical composition.

Chang’e 4 won't be returning any moon rocks to Earth, but a successor mission planned for 2019, Chang'e 5, will. This would be the first time that materials from the moon have been brought back to Earth since the Soviet Union's Luna 24 mission in 1976.

"These missions are taking place in rapid succession, and that also demonstrates the resolve of this program to move forward toward the eventual goal of putting Chinese astronauts on the lunar surface," Bradley Jolliff, a planetary scientist at Washington University in St. Louis, told NBC News MACH in an email.

China has also announced plans to launch a rover to Mars in 2020, as well as additional crewed missions to low-Earth orbit.

China had been constructing its own space station, Tiangong-2. But a rocket glitch in July 2017 derailed the effort, and China is now planning to de-orbit the 8.6-ton space lab next summer, Space News reported. In April, China's defunct Tiangong-1 space station plummeted through Earth's atmosphere and burned up over the Pacific Ocean.

China, the U.S. and Russia are the only nations to have successfully landed spacecraft on the moon.

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• Scientists discover water ice on moon's surface. Here's why that's big news. </s> The suite of instruments on the rover and the lander include cameras, ground-penetrating radar and spectrometers to help identify the composition of rocks and dirt in the area. And China's space agency has collaborated with other countries. One instrument was developed at Kiel University in Germany; another was provided by the Swedish Institute of Space Physics.

The instruments will probe the structure of the rocks beneath the spacecraft, study the effects of the solar wind striking the lunar surface. Chang'e-4 will also test the ability of making radio astronomy observations from the far side of the moon, without the effects of noise and interference from Earth.

According to the Xinhua News Agency, Chang'e-4 is also carrying an intriguing biology experiment to see if plant seeds will germinate and silkworm eggs will hatch in the moon's low gravity.

How will the spacecraft communicate with Earth?

Because the moon blocks radio signals from our planet, the Chinese launched a satellite, called Queqiao, in May.It is circling high over the far side of the moon, and will relay messages between Earth and the Chang'e-4 lander.

How do I watch the launch?

There has been no announcement of live coverage of the launch. If The New York Times learns of a live video stream from the Xichang Satellite Launch Center in southwest China, it will be posted to nytimes.com before the launch.

When will Chang'e-4 land on the moon?

China's space agency has not announced a landing date, though some expect that will be the first week of January, when the sun will be shining over the far side of the moon, an important consideration because Chang'e-4 is solar-powered.

Zhang Xiaoping, an associate professor from Space Science Institute/Lunar and Planetary Science Laboratory of Macau University of Science and Technology, said that the spacecraft would follow the Chang'e-3's trajectory. That means it would arrive in three to five days and then orbit the moon for several days (13 in the case of Chang'e-3) while preparing for the landing, he said.

Wait, I thought the far side of the moon was dark.

The far side is not dark all of the time.

The first new moon of 2019 is Jan. 6. That's when you cannot see the moon because the dark side — the side that is in shadow facing away from the sun — is facing Earth. And when the near side of the moon is dark, the far side is awash in bright sunshine.

Why is China so secretive about all of this?

Chinese officials have talked about Chang'e-4 in public, but their interactions with journalists more resemble the carefully managed strategy used by the Soviet program during the Cold War rather than the more open publicity by NASA and many other space agencies. That way, the Chinese, like the Soviets, could boast about the successes and downplay any failures.

What does Chang'e mean?

In Chinese mythology, Chang'e is the goddess of the moon. Other missions have been named after her, too.

Chang'e-1 and 2 went into orbit around the moon but did not land. Chang'e-1 was launched in 2007. Chang'e-2 followed in 2010.

The next step in China's moon program is for the Chang'e-5 robotic spacecraft to land on the moon and then bring rock samples back to Earth for additional study.

Chang'e-5 was supposed to head to the moon before Chang'e-4, but a launch failure of the large Chinese rocket needed to carry it to space delayed the mission until at least 2019.

Who else is planning to go to the moon?

Next year, the Indian government is planning to launch a mission, Chandrayaan-2, that includes an orbiter, a lander and a rover. SpaceIL, an Israeli team that was a finalist in the Google Lunar X Prize, is also still aiming to send a robotic lander to the moon early next year, even though the $20 million (U.S.) prize has expired.

NASA announced last week that nine companies will compete for robotic missions to carry science experiments to the moon. The space agency said the first of those could go as early as 2019, but most of the companies said they would not be ready until 2021.

Jim Bridenstine, the NASA administrator, has praised the Chang'e-4 mission as exciting, and at the International Astronautical Congress in Bremen, Germany in October, talked of possible collaboration with the Chinese space agency. Federal laws limit any NASA interaction with the Chinese. </s> Media playback is unsupported on your device Media caption Far side of Moon captured by Chinese spacecraft

China says it has successfully landed a robotic spacecraft on the far side of the Moon, the first ever such attempt and landing.

At 10:26 Beijing time (02:26 GMT), the un-crewed Chang'e-4 probe touched down in the South Pole-Aitken Basin, state media said.

It is carrying instruments to analyse the unexplored region's geology, as well to conduct biological experiments.

The landing is being seen as a major milestone in space exploration.

There have been numerous missions to the Moon in recent years, but the vast majority have been to orbit, fly by or impact. The last crewed landing was Apollo 17 in 1972.

Why China has its eye on the stars

Image copyright EPA/CNSA Image caption All pictures and data have to be bounced off a separate satellite

The Chang'e-4 probe has already sent back its first pictures from the surface, which were shared by state media.

With no direct communication link possible, all pictures and data have to be bounced off a separate satellite before being relayed to Earth.

Why is this Moon landing so significant?

Previous Moon missions have landed on the Earth-facing side, but this is the first time any craft has landed successfully on the unexplored and rugged far side.

Some spacecraft have crashed into the far side, either after system failures, or after they had completed their mission.

Ye Quanzhi, an astronomer at Caltech, told the BBC this was the first time China had "attempted something that other space powers have not attempted before".

Image copyright EPA/CNSA Image caption The far side is not visible from the Earth due to "tidal locking"

The Chang'e-4 was launched from Xichang Satellite Launch Centre in China on 7 December; it arrived in lunar orbit on 12 December.

It was then directed to lower itself toward the Moon, being careful to identify and avoid obstacles, Chinese state media say.

The Chang'e-4 probe is aiming to explore a place called the Von Kármán crater, located within the much larger South Pole-Aitken (SPA) Basin - thought to have been formed by a giant impact early in the Moon's history.

"This huge structure is over 2,500km (1,550 miles) in diameter and 13km deep, one of the largest impact craters in the Solar System and the largest, deepest and oldest basin on the Moon," Andrew Coates, professor of physics at UCL's Mullard Space Science Laboratory in Surrey, told the BBC.

The event responsible for carving out the SPA basin is thought to have been so powerful, it punched through the Moon's crust and down into the zone called the mantle. Researchers will want to train the instruments on any mantle rocks exposed by the calamity.

The science team also hopes to study parts of the sheet of melted rock that would have filled the newly formed South Pole-Aitken Basin, allowing them to identify variations in its composition.

A third objective is to study the far-side regolith, the broken up rocks and dust that make up the surface, which will help us understand the formation of the Moon.

What else might we learn from this mission?

Chang'e-4's static lander is carrying two cameras; a German-built radiation experiment called LND; and a spectrometer that will perform low-frequency radio astronomy observations.

Scientists believe the far side could be an excellent place to perform radio astronomy, because it is shielded from the radio noise of Earth. The spectrometer work will aim to test this idea.

Image copyright Getty Images Image caption A mock-up of the Chang'e-4 lander and rover, on display in Dongguan, China

The lander also carried a container with six live species from Earth - cotton, rapeseed, potato, fruit fly, yeast and arabidopsis (a flowering plant) - to try to form a mini biosphere.

The arabidopsis plant may produce the first flower on the Moon, Chinese state media say.

Other equipment/experiments include:

A panoramic camera

A radar to probe beneath the lunar surface

An imaging spectrometer to identify minerals

An experiment to examine the interaction of the solar wind (a stream of energised particles from the Sun) with the lunar surface

The mission is part of a larger Chinese programme of lunar exploration. The first and second Chang'e missions were designed to gather data from orbit, while the third and fourth were built for surface operations.

Chang'e-5 and 6 are sample return missions, delivering lunar rock and soil to laboratories on Earth.

Is there a 'dark side of the Moon'?

The lunar far side is often referred to as the "dark side", though "dark" in this case means "unseen" rather than "lacking light". In fact, both the near and far sides of the Moon experience daytime and nighttime.

But because of a phenomenon called "tidal locking", we see only one face of the Moon from Earth. This is because the Moon takes just as long to rotate on its own axis as it takes to complete one orbit of Earth.

The far side has a thicker, older crust that is pocked with more craters. There are also very few of the "maria" - dark basaltic "seas" created by lava flows - that are evident on the near side.

How will scientists keep track of the rover?

In an article for the US-based Planetary Society in September, Dr Long Xiao from the China University of Geosciences (Wuhan), said: "The challenge faced by a far side mission is communications. With no view of Earth, there is no way to establish a direct radio link."

So the landers must communicate with Earth using a relay satellite named Queqiao - or Magpie Bridge - launched by China last May.

Queqiao orbits 65,000km beyond the Moon, around a Lagrange point - a kind of gravitational parking spot in space where it will remain visible to ground stations in China and other countries such as Argentina.

What are China's plans in space?

China wants to become a leading power in space exploration, alongside the United States and Russia.

In 2017 it announced it was planning to send astronauts to the Moon.

It will also begin building its own space station next year, with the hope it will be operating by 2022.

The chief designer of China's lunar exploration programme, Wu Weiren, has described Thursday's landing as "an important milestone" for the country's space effort, state media report.

Image copyright Reuters Image caption A full-size model of the Tianhe core module of China's space station

The BBC's John Sudworth in Beijing says the propaganda value of China's leaps forward in its space programme has been tempered by careful media management. There was very little news of the Chang'e 4 landing attempt before the official announcement it had been a success.

But Fred Watson, who promotes Australia's astronomy endeavours as its astronomer-at-large, says the secrecy could simply be down to caution, similar to that shown by the Soviet Union in the early days of its competition with Nasa.

"The Chinese space agency is a young organisation, but perhaps in years to come, it will catch up," he told the BBC.

Ye Quanzhi says China has made efforts to be more open.

"They live-streamed the launch of Chang'e 2 and 3, as well as the landing of Chang'e 3. PR skills take time to develop but I think China will get there," he said.

China has been a late starter when it comes to space exploration. Only in 2003, it sent its first astronaut into orbit, making it the third country to do so, after the Soviet Union and the US.

The far side landing has already been heralded by experts at Nasa as "a first for humanity and an impressive accomplishment".
Chang'e 4 successfully enters orbit around the Moon ahead of a historic landing on the far side of the Moon in early 2019.