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China launches historic mission to land on far side of the moon
December 7, 2018 Stephen Clark

A view of the far side of the moon and the distant Earth, captured by the service module for the Chang’e 5-T1 tech demo mission in 2014. Credit: Chinese Academy of Sciences

A robotic lander and rover lifted off Friday (U.S. time) from China’s Xichang space center, kicking off a journey through space that will culminate in an attempt in early January to touch down on the far side of the moon for the first time.

The Chang’e 4 mission — the fourth in China’s main line of lunar explorers — lifted off at around 1823 GMT (1:23 p.m. EST) Friday from Xichang, an inland spaceport nestled between hills in southwestern China’s Sichuan province.

Chang’e 4 climbed into the night sky at Xichang — liftoff occurred at 2:23 a.m. Beijing time Saturday — toward the east affixed to the top of a Long March 3B rocket.

Chinese state television did not broadcast the launch live, as it did for China’s previous lunar mission launch in 2013, but spectators near Xichang streamed live video of the middle-of-the-night blastoff online without commentary. The video showed the Long March 3B disappearing into the night sky a few minutes after an apparently smooth liftoff from Xichang.

The three-stage Long March 3B rocket was programmed to inject the Chang’e 4 spacecraft on a trajectory toward the moon less than a half-hour after liftoff.

Chang’e 4 is expected to enter lunar orbit later this month, then use braking rockets to descend to the moon’s surface, targeting a landing in Von Karman crater in moon’s South Pole-Aitken basin region in early January.

No mission has explored the surface of the far side of the moon before, and if successful, Chang’e 4 will be a major first in space exploration, reaching a destination that has long been on the to-do list for NASA and international space scientists.

Chang’e 4 uses spare hardware built for China’s Chang’e 3 lunar lander and rover, which arrived at the moon in December 2013 with a touchdown in the Mare Imbrium volcanic basin on the near side of the moon.

The rover ceased driving a few weeks after landing, but some of the craft’s instruments continued to function for a couple of year, and the stationary lander — a carrier module that delivered the rover to the lunar surface — was still operating in an update issued earlier this year. The Chang’e 3 rover, named Yutu and designed to drive up to 6 miles (10 kilometers), traveled around 374 feet (114 meters) before losing its mobility, according to Chinese scientists.

“There are plenty of successful missions with successful landings on the near side of the moon, including Chang’e 3 in Mare Imbrium,” said Jun Huang from the Planetary Science Institute at the China University of Geosciences, in a presentation to U.S. scientists in March at the Lunar and Planetary Science Conference in Texas. “This mission has lasted for nearly five years, and it increased our knowledge about the moon greatly, however, we don’t have (until Chang’e 4) a mission dedicated to taking precision mesurements of the far side of the moon.”

There are some key differences between Chang’e 3 and Chang’e 4. For example, the lander heading for the far side of the moon will not carry a robotic arm or an Active Particle X-ray Spectrometer, an instrument capable to measuring the chemical elements in lunar rocks and soil.

In addition to a suite of cameras on both the stationary lander and rover, the mission aims to deliver a new set of sensors to the lunar surface, some of which are provided by European scientists.

The landing module, which will make a rocket-powered landing on the moon like Chang’e 3, will carry a low frequency radio spectrometer developed by Chinese scientists for astrophysics research. A German-developed neutron and dosimetry instrument will measure radiation levels at the Chang’e 4 landing site, collecting data that could be useful in planning human exploration of the lunar far side, studying solar activity, and gauging the underground water content in Von Karman crater.

The Chang’e 4 rover will host a ground-penetrating radar to study geologic layers buried under the landing site, and a visible and near-infrared spectrometer to gather data on soil composition. Chinese officials approved the addition of a Swedish instrument to study the interaction between the solar wind and the lunar surface, which is not shielded by an atmosphere from the bombardment of charged particles originating at the sun.

Chang’e 4 will also deliver to the moon a student-designed carrier containing potato seeds and silkworm eggs. University students and scientists will monitor the growth of the organisms, which will be housed inside a chamber and fed natural light and nutrients once on the lunar surface.

Source: China launches historic mission to land on far side of the moon

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Odp: [SFN] China launches historic mission to land on far side of the moon
« Odpowiedź #1 dnia: Grudzień 08, 2018, 08:15 »
China launches Chang’e-4 spacecraft for pioneering lunar far side landing mission
by Andrew Jones — December 7, 2018 [SpaceNews]

Launch of the Long March 3B rocket carrying Chang'e-4 at 18:23 UTC Dec. 7. Credit: CASC

 HELSINKI — China launched its Chang’e-4 moon mission Dec. 7, successfully sending the lander and rover into a lunar transfer orbit ahead of an unprecedented attempt at a landing on the far side of the moon early in the New Year.

Liftoff of the Long March 3B launch vehicle carrying Chang’e-4 occurred at 1:23 p.m. Eastern time Dec. 7 (02:23 a.m. local time Dec. 8) at the Xichang Satellite Launch Center in southwest China.

The timing of the launch was revealed only through airspace closure notices and no official live coverage was available, though a group of spectators streamed the event online from a viewing area.

The China Aerospace Science and Technology Corporation (CASC), the main contractor for China’s space program, officially announced success of the launch following trans-lunar injection, just under an hour after launch. The spacecraft now enters a five-day voyage to the moon before lunar orbit injection.

The Chang’e-4 mission consists of a lander and rover with a combined mass of just under four metric tons, carrying cameras and science payloads to analyze the lunar surface geology and subsurface, solar wind interactions and carry out low-frequency radio observations in the unique radio-quiet environment on the far side of the moon.

No official date has been released for the landing attempt, but CASC announced shortly after launch that the landing will take place in the first days of January 2019, following sunrise over the main candidate landing within the Von Kármán crater in late December.

As the far side of the moon never faces the Earth, communications with the spacecraft will be facilitated by the ‘Queqiao’ relay satellite launched in May and inserted into a halo orbit around the second Earth-moon Lagrange point in June.

From this vantage point between 65,000-85,000 kilometers beyond the moon the Queqiao satellite will have constant line-of-sight with both the Chang’e-4 spacecraft and Chinese ground stations in China, at Kashi and Jiamusi, Namibia and Argentina.

Chang’e-4 was originally planned as a backup to the Chang’e-3 lander and rover mission, which made China the third country to achieve a soft-landing on the lunar surface, and the first since the Soviet Union’s Luna 24 in 1976.

Payload fairing for the Chang’e-4 lunar far side mission. Credit: CASC

The spacecraft have been repurposed for a more ambitious landing on the far side of the moon, which poses far greater challenges and requirements but also the promise of great scientific payoffs.

The topography of the far side is far more rugged and variable than the near side, which is marked with vast, smooth basaltic seas or mare, which can be seen from Earth with the naked eye. The far side contains few such maria and the Chang’e-4 mission may bring insight into this mystery.

The expected target landing site selected for Chang’e-4 is thus in the relatively smooth southern portion of the 186-kilometer-diameter Von Kármán crater, though automated hazard avoidance during its descent could make the spacecraft set down elsewhere.

The crater is situated in the South Pole-Aitken Basin (SPA), a 2,500-kilometerwide, 12-kilometer-deep ancient impact crater of intense scientific interest which could contain exposed material from the moon’s upper mantle.

Investigation of the composition of areas of the SPA could reveal clues to the history of the moon and development of the wider solar system.

The lander is equipped with a Low Frequency Spectrometer (LFS) and the German-developed Lunar Lander Neutrons and Dosimetry (LND), as well as a Landing Camera (LCAM) and Terrain Camera (TCAM).

Like Chang’e-3, the rover will carry a Panoramic Camera (PCAM) and Lunar Penetrating Radar (LPR) which will reveal subsurface geological structures to depths of up to 500 meters. A Visible and Near-Infrared Imaging Spectrometer (VNIS) and Advanced Small Analyzer for Neutrals (ASAN)—the latter developed by the Swedish Institute of Space Physics, Kiruna—will also be aboard.

The mission rover, based on the Chang’e-3 Yutu (Jade Rabbit), has also been upgraded for greater longevity and addressing the issue which resulted in Yutu immobilization in its second lunar day on Mare Imbrium.

A mini biosphere experiment designed by 28 Chinese universities, containing potato and Arabidopsis seeds and silkworm eggs, will also be part of the mission to test respiration and photosynthesis in the low-gravity and high-radiation environment on the lunar surface.

A render of the Chang'e-4 lander, released on Aug. 15, 2018. Credit: CASC

Source: China launches Chang’e-4 spacecraft for pioneering lunar far side landing mission

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Odp: [SFN] China launches historic mission to land on far side of the moon
« Odpowiedź #2 dnia: Grudzień 08, 2018, 08:16 »
China launches rover for first far side of the moon landing
By Ryan McMorrow Beijing (AFP) Dec 7, 2018 []

China launched a rover early Saturday destined to land on the far side of the moon, a global first that would boost Beijing's ambitions to become a space superpower, state media said.

The Chang'e-4 lunar probe mission -- named after the moon goddess in Chinese mythology -- launched on a Long March 3B rocket from the southwestern Xichang launch centre at 2:23 am (1823 GMT), according to the official Xinhua news agency.

The blast-off marked the start of a long journey to the far side of the moon for the Chang'e-4 mission, expected to land around the New Year to carry out experiments and survey the untrodden terrain.

"Chang'e-4 is humanity's first probe to land on and explore the far side of the moon," said the mission's chief commander He Rongwei of China Aerospace Science and Technology Corp, the main state-owned space contractor.

"This mission is also the most meaningful deep space exploration research project in the world in 2018," He said, according to state-run Global Times.

Unlike the near side of the moon that is "tidally locked" and always faces the earth, and offers many flat areas to touch down on, the far side is mountainous and rugged.

It was not until 1959 that the Soviet Union captured the first images of the heavily cratered surface, uncloaking some of the mystery of the moon's "dark side".

No lander or rover has ever touched the surface there, positioning China as the first nation to explore the area.

"China over the past 10 or 20 years has been systematically ticking off the various firsts that America and the Soviet Union did in the 1960s and 1970s in space exploration," said Jonathan McDowell, an astronomer at the Harvard-Smithsonian Center for Astrophysics.

"This is one of the first times they've done something that no one else has done before."

- Next up: humans -

It is no easy technological feat -- China has been preparing for this moment for years.

A major challenge for such a mission is communicating with the robotic lander: as the far side of the moon always points away from earth, there is no direct "line of sight" for signals.

As a solution, China in May blasted the Queqiao ("Magpie Bridge") satellite into the moon's orbit, positioning it so that it can relay data and commands between the lander and earth.

Adding to the difficulties, Chang'e-4 is being sent to the Aitken Basin in the lunar south pole region -- known for its craggy and complex terrain -- state media has said.

The probe is carrying six experiments from China and four from abroad.

They include low-frequency radio astronomical studies -- aiming to take advantage of the lack of interference on the far side -- as well as mineral and radiation tests, Xinhua cited the China National Space Administration as saying.

The experiments also involve planting potato and other seeds, according to Chinese media reports.

Beijing is pouring billions into its military-run space programme, with hopes of having a crewed space station by 2022, and of eventually sending humans to the moon.

The Chang'e 4 mission is a step in that direction, significant for the engineering expertise needed to explore and settle the moon, McDowell said.

"The main thing about this mission is not science, this is a technology mission," he said.

- 'National pride' -

Chang'e-4 will be the second Chinese probe to land on the moon, following the Yutu ("Jade Rabbit") rover mission in 2013.

Once on the moon's surface, the rover faces an array of extreme challenges.

During the lunar night -- which lasts 14 earth days -- temperatures will drop as low as minus 173 degrees Celsius (minus 279 Fahrenheit). During the lunar day, also lasting 14 earth days, temperatures soar as high as 127 C (261 F).

The rover's instruments must withstand those fluctuations and it must generate enough energy to sustain it during the long night.

Yutu conquered those challenges and, after initial setbacks, ultimately surveyed the moon's surface for 31 months. Its success provided a major boost to China's space programme.

Beijing is planning to send another lunar lander, Chang'e-5, next year to collect samples and bring them back to earth.

It is among a slew of ambitious Chinese targets, which include a reusable launcher by 2021, a super-powerful rocket capable of delivering payloads heavier than those NASA and private rocket firm SpaceX can handle, a moon base, a permanently crewed space station, and a Mars rover.

"Our country's successful lunar exploration project not only vaults us to the top of the world's space power ranks, it also allows the exploration of the far side of the moon," said Niu Min, an expert on China's space programme.

The project, he said in an interview with local website Netease, "greatly inspires everyone's national pride and self-confidence".

Source: China launches rover for first far side of the moon landing

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Odp: [SFN] China launches historic mission to land on far side of the moon
« Odpowiedź #3 dnia: Grudzień 31, 2018, 09:47 »
Chang’e-4 landing to be a step along a road of lunar exploration for China
by Andrew Jones — December 28, 2018 [SpaceNews]
This article originally appeared in the Dec. 17, 2018 issue of SpaceNews magazine.

China will attempt to land the Chang’e-4 lunar lander on the moon’s farside in January. Credit: Chinese Academy of Sciences illustration

With its Chang’e-4 spacecraft now orbiting the moon in preparation for the first-ever landing on the far side of Earth’s nearest neighbor, China is poised to reap the prestige and scientific payoffs that are part and parcel of achieving a space first.

Despite being a repurposed backup to the 2013 Chang’e-3 landing, Chang’e-4’s planned January touch down on the far side of the moon will also be a steppingstone to further and more ambitious robotic lunar exploration missions.

“Chang’e-4 will validate further technologies of landing, enhanced rover operations and more complex far side communications. It also uses more powerful instruments,” Bernard Foing, director of the European Space Agency’s International Lunar Exploration Working Group, told SpaceNews.

Communications between Chang’e-4 on the far side (which never faces the Earth) and Chinese tracking stations will be facilitated by Queqiao (‘Magpie Bridge’), a relay satellite with a 4.2-meter-diameter parabolic antenna that China launched in May to orbit around the second Earth-moon Lagrange point beyond the moon.

Chang’e-4 uses new hazard-avoidance algorithms, a more vertical descent and smaller landing footprint than its predecessor mission to handle the more variable and rugged topography of the lunar far side, which features few of the smooth, flat maria of the near side.

This is “absolutely a significant step,” James Head, a planetary scientist at Brown University in Providence, Rhode Island, told SpaceNews.

“Gaining confidence in far side landings opens ‘the other continent’ for full exploration and sample return, and to a treasure trove of scientific targets and fundamental scientific results. Chang’e-4 is a total game-changer in terms of gaining access to ‘Luna Incognita’ and is akin to Columbus’ voyages to the New World,” according to Head.

A more precise landing in a challenging landscape will also be useful for missions to the lunar south pole, which China is now formulating to extend the Chang’e robotic lunar program and establish what is described as a lunar research base with three or four missions across the 2020s.

One of the key goals of Chang’e-7, which would launch around 2021, will be to detect water ice and determine its origin in permanently shadowed areas, according to a paper from authors including Zou Yongliao, a senior lunar scientist with the National Space Science Center under the Chinese Academy of Sciences, presented at the International Symposium on Lunar and Planetary Science 2018 in Macau, China, in June. Further missions will include in-situ resource utilization and technology verification tests.

Before this, China plans to follow up Chang’e-4 with the Chang’e-5 near side sample return mission, possibly in late 2019, once the Long March 5 — which suffered a high-profile failure in July 2017 — has at least one successful flight.

This will be a notable step-up in capability from the Chang’e-4 mission says John Horack, the Neil Armstrong Chair in Aerospace Policy at Ohio State University.

“The complexity of Chang’e-5 will require mastery of capabilities such as lunar orbit rendezvous, robotic sample collection, automated spacecraft docking, launching from the moon using a vehicle that has itself soft-landed on the moon, higher temperature re-entry systems for deceleration at Earth, and more. These are all capabilities that could fortify larger space exploration systems in the future, or even eventual human exploration of the moon by China,” Horack told SpaceNews.

Though there is no official government-approved Chinese human lunar exploration program, institutes under the China Aerospace Science and Technology Corporation, the main contractor for the Chinese space program, are working on capabilities required to put astronauts on the lunar surface.

The far side of the moon and distant Earth imaged by the Chang’e-5 T1 mission service module in 2014. Credit: Chinese Academy of Sciences photo

The China Academy of Space Technology has made progress on a next-generation crewed spacecraft, one variant of which will be up to 20 metric tons and have an uncrewed test flight on a test launch of the Long March 5B launch vehicle in 2019 or 2020. The craft is designed to take up to six astronauts to deep space and the moon, while the current 8-ton Shenzhou can take three to low Earth orbit.

In October, the China Academy of Launch Vehicle Technology unveiled a model of a conceptual design for a human-rated launch vehicle at the 12th China International Aviation and Aerospace Exhibition in Zhuhai, southern China.

The design uses clusters of already-developed YF-100K kerosene- and liquid-oxygen engines and 5-meter-diameter cores like those of the Long March 5, making its development, if approved, much faster, potentially providing China with the launch capabilities to carry out human lunar exploration of the moon much sooner than previously expected.

A previous mission concept for putting Chinese astronauts on the lunar surface required the Long March 9, a super-heavylift launcher with a 10-meter diameter that China aims to fly in 2028. This profile also includes the lofting of the crew via a Long March 5B and an Earth-orbit rendezvous.

There is however a long road to travel before these plans and concepts can be realized and sustained. “China is a large and very complicated place, with significant challenges related to infrastructure, growth, environmental degradation, poverty and more,” Horack notes.

“Successful execution of space exploration missions are indeed testament to their substantive technical capability, and to their exceptional growth as a nation. But sustainability in space is a function of much more than only whether one can execute missions.

“We have seen this play out in earlier situations. The Apollo program’s unparalleled and extensive capability in sending human beings to the moon, derived at great cost, was not itself sufficient to sustain the activity and has not been replicated now for 50 years,” Horack cautions. For now, though, China is demonstrating momentum in lunar exploration.

“It is impressive to see how the comprehensive plan they have prepared has been implemented step by step with reliable expertise and schedule,” says Foing, who collaborated with Chinese colleagues from the start of the Chang’e program and prepared the initial collaboration agreement between ESA and CNSA.

A successful landing for Chang’e-4 could mark another big step on a path of lunar exploration that China has laid out and is keen to advance along.

Source: Chang’e-4 landing to be a step along a road of lunar exploration for China

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Odp: [SFN] China launches historic mission to land on far side of the moon
« Odpowiedź #4 dnia: Styczeń 03, 2019, 14:57 »
Chang’e-4 makes historic first landing on the far side of the moon 
by Andrew Jones — January 3, 2019 [SpaceNews]

A render of the Chang'e-4 rover on the lunar surface, released Aug. 15, 2018 (Credit: CASC)

HELSINKI, Finland — China’s Chang’e-4 spacecraft made the historic first ever soft-landing on the far side of the moon Jan. 2 in a mission aims to reveal clues to the history of the solar system.

The 1,200-kilogram dry mass Chang’e-4 lander touched down within Von Kármán crater at 9:26 p.m. Eastern, according to a Chinese state media announcement 90 minutes later.

The spacecraft began its descent from a perilune of 15 kilometers with a burn of its single main variable thruster at before entering approach, hazard avoidance and slow descent phases and a soft landing.

The lander and the companion 140-kilogram rover, which is expected tp be deployed within the coming hours, will work toward science goals including analyzing the lunar surface and subsurface composition, assessing the radiation environment and its interaction with the regolith and low frequency radio astronomy, as well as returning high-resolution images from terrain and panoramic cameras.

Chang’e-4 launched Dec. 8 and had been in lunar orbit since Dec. 12, where it tested communications and refined its orbit in preparation for a landing timed to follow sunrise over the target site, allowing the mainly solar-powered craft to begin operations immediately.

The 186-kilometer-diameter Von Kármán crater containing the landing site is situated within the 2,500-kilometerwide South Pole-Aitken (SPA) basin, which is one of the oldest and largest impact craters in the solar system.

The basin could contain exposed material from the moon’s upper mantle and promises clues to the history and development of the solar system. A sample return from the SPA basin has been noted as a priority in past U.S. Planetary Science Decadal Surveys.

Chang’e-4 is the repurposed backup spacecraft to the Chang’e-3 mission, which landed on Mare Imbrium on the near side in December 2013, making China only the third country to soft-land on the moon.

While the Chang’e-3 rover, on which the Chang’e-4 is based, traveled just 114 meters before being rendered immobile on Mare Imbrium in early 2014, officials with the China Academy of Space Technology (CAST), the spacecraft’s manufacturer, have stated that the issue has been identified and addressed and that the new rover has been upgraded for greater reliability and longevity.

The landing comes ahead a wave of renewed interest in lunar exploration, with NASA, ESA, Russia, India and private companies working on a range of missions.

The China Aerospace Science and Technology Corporation (CASC) also announced Wednesday that it plans to launch the Chang’e-5 near side sample return mission with the second of two planned Long March 5 heavy-lift rocket launches in 2019.

Far side communications and landing challenges

Targeting the far side of the moon, which due to tidal locking never faces the earth, required the prior launch of a relay satellite to the second Earth-moon Lagrange point some 65,000-85,000 kilometers beyond the moon to facilitate communications.

Named Queqiao (‘Magpie bridge’ from Chinese mythology), the satellite has been in a halo orbit around this gravitationally stable libration point since June, from which has constant line-of-sight with both the terrestrial tracking stations—situated in China, Namibia and Argentina—and the lunar far side.

Apollo 17 Crew member and geologist Harrison Schmitt had recommended the final mission of NASA crewed landing program target the Tsiolkovskiy crater on the far side using a relay satellite, but the suggestion was rejected on grounds of risk and cost.

The more rugged and variable lunar far side typography and near absence of dark, basaltic plains or maria, demanded upgrades to the Chang’e-4 guidance, navigation and control systems, a much smaller landing footprint and more vertical and accurate powered descent than the predecessor mission. The landing will also assist in the execution of the country’s future lunar exploration plans.

Ian Crawford, professor of planetary science and astrobiology at Birkbeck, University of London, told SpaceNews ahead of the event that a safe landing would be a “fantastic achievement.”

“This will give valuable information on the composition of the far side crust and, conceivably, the upper mantle…The radio astronomy experiments are also of great interest, which may lay a foundation for the development of lunar far side radio astronomy,” Crawford said.

Chang’e-4 science goals

Robert F. Wimmer-Schweingruber of the University of Kiel, Germany, which led the development of the Lunar Lander Neutrons and Dosimetry (LND) experiment, told SpaceNews that LND can, “help us understand the radiation which lunar soils and rocks are exposed to and to detect sub-surface water.”

“Its main purpose, however, is to prepare for human exploration of the moon by measuring the radiation to which astronauts will be exposed,” says Wimmer-Schweingruber, and specifically the neutron dose rate on the surface of the moon.

LND is one of four international payloads involved in the Chang’e-4 mission, along with the Advanced Small Analyzer for Neutrals (ASAN) from Sweden aboard the rover, the Netherlands-China Low-Frequency Explorer (NCLE) on Queqiao and a small camera on the Longjiang-2 microsatellite.

James Head, a planetary scientist at Brown University in Providence, Rhode Island, told SpaceNews in December that the Lunar Penetrating Radar (LPR), an instrument also aboard the Chang’e-3 rover, will provide images of the structure of the lunar soil layers and any subsurface lava flow units.

The Visible and Near-Infrared Imaging Spectrometer (VNIS), likewise installed on the mobile rover, will allow analysis of the mineralogy of the floor of Von Kármán crater and ejecta delivered by later, nearby impacts, according to Head.

The Low Frequency Spectrometer (LFS) payload on the Chang’e-4 lander will make astronomical observations in low frequency bands in a unique radio-quiet environment free of interference from the earth.

Another payload included in the mission through an outreach initiative is a small biosphere containing Arabidopsis and potato seeds along with silkworm cocoons, designed and developed in collaboration with 28 Chinese universities.

The experiment will be a pioneering test of photosynthesis and respiration in the one-sixth Earth gravity lunar environment, with a possible live steam to the 3-kilogram, 0.8-liter capacity cannister.

Anna-Lisa Paul, space biologist and research professor at University of Florida-Gainesville, told SpaceNews that the experiment will be unique, despite awealth of experiments that have grown plants and invertebrates in habitats on the Space Shuttle, the International Space Station, MIR, Skylab and others.

“We already know that plants, including Arabidopsis and potato, and silkworms do just fine in the microgravity of the spaceflight environments, so a climate-controlled biosphere on the surface of the moon will probably be reasonably benign, yet it is huge from the perspective that it has not been done.”

Source: Chang’e-4 makes historic first landing on the far side of the moon

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Odp: [SFN] China launches historic mission to land on far side of the moon
« Odpowiedź #5 dnia: Styczeń 03, 2019, 15:43 »
Xinhua Headlines: China's Chang'e-4 probe makes historic landing on moon's far side
Source: Xinhua| 2019-01-03 20:57:42|Editor: Liangyu

Photo provided by the China National Space Administration on Jan. 3, 2019 shows the first image of the moon's far side taken by China's Chang'e-4 probe. China's Chang'e-4 probe touched down on the far side of the moon Thursday, becoming the first spacecraft soft-landing on the moon's uncharted side never visible from Earth. The probe, comprising a lander and a rover, landed at the preselected landing area at 177.6 degrees east longitude and 45.5 degrees south latitude on the far side of the moon at 10:26 a.m. Beijing Time (0226 GMT), the China National Space Administration announced. (Xinhua)

by Xinhua writers Yu Fei, Quan Xiaoshu, Xie Jiao

BEIJING, Jan. 3 (Xinhua) -- No wind blows and no rain falls there. Only crashing meteorites occasionally disrupt the stillness. The desolate landscape on the far side of the moon - never visible from Earth - has waited billions of years to see the first-ever soft landing of a visitor from Earth.

After orbiting the moon for more than 20 days, the Chang'e-4 probe, launched from the Xichang Satellite Launch Center in southwest China on Dec. 8, 2018, has seen countless craters, mountains and valleys on the moon.

Finally, its destination on the far side, the South Pole-Aitken (SPA) Basin, the largest, deepest and oldest crater in the solar system, was illuminated by the rising sun.

The developers of Chang'e-4 decided on Thursday it was the time to come down on this barren world.

At 10:15 a.m., a variable thrust engine was ignited with the assistance of the relay satellite Queqiao (Magpie Bridge), operating in the halo orbit around the second Lagrangian (L2) point of the Earth-moon system, about 65,000 km from the moon, where it can see both Earth and the moon's far side.

Chang'e-4's relative velocity to the moon was lowered from 1.7 km per second to close to zero, and the probe was adjusted to face the moon and descend vertically towards the Von Karman Crater in the SPA Basin.

When it descended to an altitude of about 2 km, its cameras captured the shadows of the hills and valleys on the lunar surface. Its computer identified and assessed large obstacles such as rocks and craters, so the probe could avoid them.

At 100 meters up, the probe hovered to identify smaller obstacles and measured the slopes on the surface. Its computer calculated again and selected the safest site.

At 2 meters above the surface, the engine stopped, and then the golden lander with a silver rover on top touched down on the desolate gray surface with four legs, throwing up some dust.

The probe performed the entire landing process, lasting about 12 minutes with no intervention from ground control, and the relay satellite transmitted the first close-up photos of the moon's far side back to a control center in Beijing.

The China National Space Administration later announced that the probe landed at the preselected landing area at 177.6 degrees east longitude and 45.5 degrees south latitude on the far side of the moon.

"It's an important milestone for China's space exploration," said Wu Weiren, chief designer of China's lunar exploration program.

"It is a perfect display of human intelligence," said Jia Yang, deputy chief designer of the Chang'e-4 probe, from the China Academy of Space Technology (CAST).

Named after Chinese moon goddess "Chang'e," China's lunar exploration program, which began in 2004, includes orbiting and landing on the moon, and bringing samples back to Earth.

After Chang'e-3 completed China's first soft landing on the moon in 2013, Chinese space experts aimed high, hoping Chang'e-4 could carry out unprecedented and more challenging tasks.

"Landing on the far side of the moon is more risky than landing on the near side. The rugged terrain on the far side has raised many problems," said Sun Zezhou, chief designer of Chang'e-4 probe, from CAST.

"But solving those problems might help lay the foundation for future space exploration. High-precision landing is a necessity for further exploring the moon and asteroids. We hope to be able to reach the whole moon and even the whole solar system," Sun said.

"The far side of the moon has unique features never before explored on site," said Zou Yongliao, director of the lunar and deep space exploration division of the Chinese Academy of Sciences (CAS). "The exploration of this virgin land by Chang'e-4 might bring breakthroughs."

The moon is tidally locked to earth, rotating at the same rate that it orbits Earth, so one side of the moon is seen from Earth, leaving the far side a mystery, until now.

About 60 years ago, the Soviet Union's Luna 3 probe sent back the first images of the moon's far side. And about 50 years ago, three astronauts on the United States Apollo 8 mission became the first people to see it with their own eyes.

Lunar orbiters have shown the moon's two sides are very different: the near side is relatively flat, while the far side is thickly dotted with impact craters of different sizes.

Scientists believe that the lunar crust on the far side is much thicker than the near side. However, the reason is still a mystery. Only on site exploration might reveal the secrets.

The moon and Earth shared a similar "childhood." But traces of the remote past on Earth have been erased by geological activities. "The moon might provide some insights to the early history of Earth," said Lin Yangting, a researcher at the Institute of Geology and Geophysics.

Exploring the Von Karman Crater in the SPA Basin is meaningful in another sense. The crater was named after a Hungarian-American mathematician, aerospace engineer and physicist in the 20th century, who was also the teacher of Qian Xuesen and Guo Yonghuai, the founders of China's space industry.

Nearly 50 years have passed since people first stood on the moon. Can we return? How will radiation on the moon affect astronauts? How much water is there?

Scientists from China, Germany and Sweden hope to find the answers through Chang'e-4, and make preparations for people to return to the moon.

Professor Robert Wimmer-Schweingruber, of the Institute of Experimental and Applied Physics of Kiel University in Germany, said that preparing for future human exploration of the moon was an excellent idea.

"If astronauts come back to Earth, the radiation on the moon is the only danger that remains in their body. So we need to understand that," he said.

Johan Koehler, head of Solar System Science and Space Situational Awareness, Swedish National Space Agency, said exploration of the far side of the moon was a great achievement by China. "We are very happy to be a part of it."

"There is a theory that water on the surface of the moon is formed by the interaction of solar wind with the surface regolith. So this is something that Swedish scientists together with Chinese scientists want to answer," said Koehler.

The Chang'e-4 mission, including the probe, the relay satellite Queqiao and a micro satellite orbiting the moon, is equipped with four payloads developed through international cooperation, providing more opportunities to the world's scientists and combining human expertise in space exploration.

"I think one of the beauties of space science is that we do cooperate internationally. Space science to me is something important, also as a message of peace worldwide," Wimmer-Schweingruber said.

For astronomers, the far side of the moon is a place of ideal tranquility, as the body of the moon shields against radio interference from Earth. From there, they can study the origins and evolution of stars and galaxies, peering into the dawn of the universe.

Chang'e-4 carries low-frequency radio astronomical instruments developed by Chinese and Dutch scientists. "Conducting such observation on the moon's far side is a long cherished goal of astronomers, and could fill gaps in astronomical observation,"said Zou.

The probe also took six live species - cotton, rapeseed, potato, arabidopsis, fruit fly and yeast - to the lifeless environment to form a mini biosphere, which is expected to produce the first flower on the moon.

Chinese space engineers also plan to get data by constantly measuring temperatures on the surface of the moon.

"Exploring the far side of the moon is one contribution China is making to the world. Although we still don't know what we might find, this exploration might influence several generations," said Shen Zhenrong, a designer of the lunar rover.

Wu Weiren said: "Exploring the unknown is human nature. The moon is a mysterious world to us. We have a responsibility to explore and to understand it. Exploration of the moon will also deepen our understanding of Earth and ourselves."

Source: Xinhua Headlines: China's Chang'e-4 probe makes historic landing on moon's far side

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Odp: [SFN] China launches historic mission to land on far side of the moon
« Odpowiedź #6 dnia: Styczeń 25, 2019, 21:56 »
Sukcesy i porażki chińskiego eksperymentu z uprawą roślin na Księżycu
Przez Michał Michałowski - 17 stycznia 2019 [We need more space]

Po raz pierwszy w historii na Księżycu wykiełkowało nasiono. Trafiło tam ono we wnętrzu chińskiego lądownika Chang’e 4, który na początku roku osiadł po niewidocznej stronie Srebrnego Globu. Uprawa roślin w trudnych księżycowych warunkach to jeden z głównych eksperymentów tej misji. Osiągnięcie naukowców z Uniwersytetu Chongqing w niedalekiej przyszłości może przyczynić się do opracowania rozwiązań, które umożliwią załogowe loty na Księżyc, Marsa i inne odległe obiekty w przestrzeni kosmicznej.

Własny Eden na Księżycu

Po miękkim lądowaniu statku Chang’e 4 w kraterze Von Kármána rozpoczęto pionierski eksperyment z udziałem mini biosfery opracowany przez zespół profesora Xie Gengxina z Uniwersytetu Chongqing. Składała się ona z nasion bawełny, rzepaku, ziemniaków i rzodkiewnika, a także jajeczek muszek owocówek i drożdży. Docelowo owady żerujące na roślinach wyprodukowałyby dwutlenek węgla potrzebny do rozwoju flory.

Dlaczego wybrano akurat te gatunki roślin? Profesor Gengxin tłumaczy, że ziemniaki mogą być ważnym źródłem pożywienia dla kosmicznych podróżników. Nie bez powodu nazywane są też super jedzeniem, a Matt Damon przeżył na nich kilkaset dni podczas swojej kinowej marsjańskiej misji. Drożdże mogą za to pełnić funkcję regulatora obiegu dwutlenku węgla i tlenu. Rzodkiewnik wybrano ze względu na szybki i łatwo obserwowalny rozwój, podobnie jak bawełnę.

Ten prymitywny ekosystem został zamknięty w ważącym 2,6 kg walcowatym pojemniku wykonanym ze specjalnego stopu aluminium. Mierzy on niewiele, bo ledwo 198 mm wysokości, o średnicy 173 mm. Zaopatrzony został on w wodę, powietrze i odpowiednią glebę. Nasiona ogrzewało naturalne światło dostarczone spoza pojemnika. W środku umieszczono oczywiście jeszcze dwie kamery, które pozwalały obserwować rozwój roślin oraz regulator temperatury.

Sukces mimo wszystko

Na nadesłanych zdjęciach z lądownika widzimy, że wykiełkowało jedynie jedno z nasion i już rozwinęło pierwszą łodyżkę (zobacz zdjęcie z początku artykułu). Niestety reszta nie miała takiego szczęścia i już nie będzie miała. W ostatnią niedzielę, 15 stycznia, lądownik Chang’e 4 wszedł w stan uśpienia, aby przetrwać rozpoczynającą się noc księżycową. Trwający wtedy mrok i ekstremalnie niskie temperatury, spadające nawet do – 170 stopni Celsjusza, nie sprzyjają rozwoju jakiejkolwiek biosfery.

Życie w pojemniku nie przetrwa księżycowej nocy – stwierdził bez owijania w bawełnę, gra słów niezamierzona, profesor Xie Gengxin. Tym samym eksperyment z biosferą zakończył się i chociaż nie udało się rozwinąć go w pełni, to nawet ta jedna mała roślina jest ogromnym sukcesem. Przez najbliższe dwa tygodnie cała zawartość pojemnika stopniowo obumrze i w żaden sposób nie zanieczyści księżycowej powierzchni.

Uprawy w kosmosie

Pierwsza księżycowa roślina to kolejne znaczące osiągnięcie dokonane w ramach misji Chang’e 4, która wydaje się być jednym z kamieni milowych w długotrwałym procesie powrotu ludzi na Księżyc. Nie jest to pierwsza próba wyhodowania flory poza Ziemią, podobne eksperymenty przeprowadzano na wielu stacjach na orbicie, a szczególnie na Międzynarodowej Stacji Kosmicznej. Uprawiano tam różne rodzaje sałaty, kapusty i roślinę ozdobną cynia.

Umiejętność hodowania roślin na statkach kosmicznych czy pozaziemskich bazach jest kluczowa, jeśli chcemy myśleć o jakiejkolwiek dłuższej i dalszej eksploracji i kolonizacji naszego Układu Słonecznego. Ludzie muszą coś jeść, a poza tym rośliny oczyszczają powietrze z dwutlenku węgla i produkują tlen. Wyhodowanie ich na Księżycu jest o wiele trudniejsze niż na stacjach kosmicznych ze względu warunki, takie jak wysoka amplituda temperatur, promieniowanie i mroczne noce.

Na wieść o kolejnym sukcesie wiceprezydent Chińskiej Administracji Kosmicznej Wu Yanhua ogłosił plany rozszerzenie programu eksploracji Księżyca Chang’e o następne trzy misje. Zebrana podczas nich wiedza, opracowane i sprawdzone rozwiązania w przyszłości miałyby umożliwić budowę międzynarodowej załogowej bazy na powierzchni.


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Odp: [SFN] China launches historic mission to land on far side of the moon
« Odpowiedź #7 dnia: Styczeń 10, 2020, 07:08 »
China publishes Chang’e 4 data one year after first landing on far side of the moon
January 6, 2020 Stephen Clark [SFN]

The Yutu 2 rover is pictured on the far side of the moon soon after landing in January 2019. This image was taken by a camera on the Chang’e 4 mission’s stationary landing platform. Credit: CNSA/CLEP

Chinese officials marked the one-year anniversary of the Chang’e 4 mission’s historic first soft landing on the far side of the moon Friday with the public release of data collected by scientific instruments and cameras on the lunar lander and rover.

The Chang’e 4 lander and Yutu 2 rover landed together on the lunar surface Jan. 3, 2019, marking the first time a spacecraft has ever safely touched down on the far side of the moon.

Around 12 hours after touchdown, the Yutu 2 rover drove down a ramp to disembark from the Chang’e 4 mission’s stationary landing platform to begin exploring the barren lunar landscape.

Scientific instruments and cameras aboard the Chang’e 4 lander and Yutu 2 rover have downlinked measurements and numerous images in the past year. The Chang’e 4 mission relays data through a dedicated Chinese communications satellite positioned beyond the far side of the moon, with a line of sight to both Chang’e 4 and Earth-based receiving stations.

On Friday, the one-year anniversary of the mission’s successful landing, China National Space Administration and the Chinese Academy of Sciences published scientific data collected by five instruments on the Chang’e 4 lander and Yutu 2 rover.

The data catalog is available for download on a public website, and is open for analysis by the global science community, Chinese officials said.

Since landing last January, the Yutu 2 rover has driven 1,173 feet (nearly 358 meters) to survey the Chang’e 4 landing site, collecting data on rock formations, taking pictures and studying the structure of the lunar crust using a ground-penetrating radar.

The mission continues operating after exceeding its planned three-month design lifetime.

The rover is powered down and put into sleep mode during each two-week-long lunar night, when the solar-powered craft can no longer generate enough electricity to power its instruments and radio transmitter.

Chang’e 4 landed in Von Kármán crater, a bowl-shaped depression measuring around 110 miles (180 kilometers) in diameter located in the southern hemisphere of the far side of the moon.

The Yutu 2 rover on the far side of the moon. Credit: CNSA/CLEP

The Yutu 2 rover was named after the mobile robot named Yutu that flew on the Chang’e 3 mission to the moon in 2013. Yutu means “jade rabbit” in Chinese, and is the name of the pet rabbit of the moon goddess Chang’e in Chinese folklore, the namesake of China’s lunar missions.

Chang’e 4’s lander and rover were originally built as spares for Chang’e 3, then modified for a new mission on the back side of the moon after Chang’e 3’s successful landing.

On Earth, the landing craft weighs around 2,600 pounds (1,200 kilograms) without its propellant, and is about the size of a car. The six-wheeled Yutu 2 rover weighs 297 pounds (135 kilograms), and measures about 4.9 feet (1.5 meters) tall.

The data release Friday included 17,239 data files containing 20.9 gigabytes of information, according to a post on a Chinese Academy of Sciences website.

The release includes images from the landing and terrain cameras on the Chang’e 4 lander, plus imagery captured by the panoramic camera on the Yutu 2 rover. Data from the rover’s ground-penetrating radar and visible and near-infrared spectrometer were also published Friday.

China has also publicly released data from its previous lunar missions.

In addition to the panoramic camera, radar and spectrometer, the Yutu 2 rover carries a Swedish instrument designed to study the interaction of the solar wind with the lunar surface.

The Chang’e 4 stationery lander carries a low frequency radio spectrometer developed by Chinese scientists for astrophysics research. A German-developed neutron and dosimetry instrument on the stationary lander is also on-board to measure radiation levels at the Chang’e 4 landing site, collecting data that could be useful in planning human exploration of the lunar far side, studying solar activity, and gauging the underground water content in Von Kármán crater.

Measurements from the Swedish and German instruments, along with the low frequency spectrometer, were not included in Friday’s data release.

The Yutu 2 rover captured this image of the Chang’e 4 lander last year. Credit: CNSA/CLEP

The next mission in China’s lunar exploration program is Chang’e 5, which will be China’s first mission to return samples from the moon.

The spacecraft — weighing some 18,000 pounds (8.2 metric tons) at launch, according to state media — will lift off on China’s heavy-lift Long March 5 rocket later this year, aiming to bring the first lunar samples back to Earth since the Soviet Union’s Luna 24 robotic mission in 1976.

A follow-up sample return mission named Chang’e 6 is also being developed by China. Unlike Chang’e 5, which is an all-Chinese mission, the Chang’e 6 spacecraft will carry foreign instruments to the lunar surface. The French space agency, CNES, announced in November that it will provide an instrument for the Chang’e 6 mission to study the moon’s exosphere and water cycle.

China is also planning robotic missions to the lunar south pole before a possible landing on the moon with Chinese astronauts in the 2030s.