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#change6

8 posts4 participants0 posts today
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The inset at top right of the previous map shows white boxes where hyperspectral observations were taken. Boxes with more than one observation number were repeat observations, and they allowed some study of changes in water concentration (VERY low) over time.
#moon #change6

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Time to put everything together for Chang'e 6. Here is a map of the immediate area of the lander. I need to confirm the location of the drill. The Lunar Mineralogy Spectrometer (LMS) did multispectral mapping of the sampling area to help find a good place to scoop. Some parts were looked at in more bands (hyperspectral), observing traces of water (top right inset). The rover route is mapped but I am still waiting for a formal paper on it for details.
#moon #change6

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The 8 scoops make a shape resembling Zhong, the Chinese character which is the first part of the country's name (Zhōngguó). C3 came between scoops 6 and 7 but I only discovered it after the image was prepared, in a paper about determining the surface strength from the imprint depth.
#moon #change6

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This video:

youtube.com/watch?v=svW5JNPAD6c

shows the Chang'e 6 sampling process. First a drill, which took a c. 100 cm core. It should have gone to 200 cm but hit a rock. Then a scoop which collected 8 scoops of regolith. Three times the scoop contacted the surface before digging (C1, C2, C3), to calibrate the position of the scoop. Later the data from the contacts was used to measure surface strength. The process was fully automated.
#moon #change6

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Less well known is this second image which appeared on a social media site which I can't get back to. But I save everything... This was taken earlier, closer to the lander. The hills in the background of both images of the lander are parts of Mons Song, south of the lander in a map I posted earlier.
#moon #change6

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That Chang'e 6 panorama was not the only image from the mission. The spacecraft had multiple cameras to monitor activities throughout surface and orbital operations, but the one which got most attention was on a tiny rover:

planetary.org/space-images/cha

It was dropped off the side of the lander and could operate whichever way up it landed. More details:

leonarddavid.com/up-close-look

That link shows a picture taken by the rover. Quite impressive!

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In this view I have projected the panorama into a semicircle with north at the top (the process exaggerates horizon relief). I also massaged the scene a little bit to make visible the 50 m subdued crater whose rim the spacecraft landed on. Otherwise it is very difficult to discern.
#moon #change6

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We landed! Let's take a look around the Chang'e 6 landing site. The sample return landers only took half a panorama, alas. Here:

english.www.gov.cn/news/202406

are some images including their panorama (second image). My version has a straightened horizon (it's a cylindrical projection). Below is a closeup of hills on the horizon, the rim of Chaffee crater. I will eventually fill the bit at the top where the flag is to maximize the surface view.
#moon #change6

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So this is a farside mare (basalt lava flow) and the regolith developed on that lava flow contains fragments thrown onto it from distant craters. The young crater Chaffee S (shown yesterday) is a likely source of some of those fragments. They would include samples of the South Pole-Aitken Basin floor, a prize long desired by lunar scientists.
#moon #change6

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Here I zoom in on the Chang'e 6 landing site. I have done this 4 frame sequence for every landing and crash site which we can identify in LRO images. The second image shows the specific target box in the larger landing area. They landed almost in the middle of it. It looks like a typical mare surface but it's anything but. This was only the second landing on the far side of the Moon and the first sample return.

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Many craters are named here. China has been quite active in getting names approved around its landing sites. You can also see craters commemorating several US astronauts (see the ALT text in the previous post) including the Columbia crew and 2 of the Apollo 1 crew. The Challenger crew are commemorated by craters north of here, and Soviet astronauts have their own craters near Tsiolkovskiy and Mare Moscoviense.
#moon #change6

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I had a thread on lunar landing sites a year or so ago, which is included in the 'planetary mapping' PDF linked in the pinned post thanks to @birchbirch. This current thread is an update, so here I am continuing where that thread finished, just leading up to Chang'e 6. Here are 2 maps for context. They show the defined landing area and a backup area further west. A specific landing box was defined within the large landing area later.

This post is not part of the regular sequence. The image shows the sampling process for Chang'e 6. I had posted it once before but this is updated . Panel A shows the surface before sampling and the sequence builds up one event at a time. C1, C2 and C3 are surface contacts used to calibrate the arm position and assess surface hardness. The other marks are the sampling scoop disturbances. C3 happened between scoops 6 and 7.
#moon #change6

[Premiers résultats de #DORN sur la #Lune] La récupération d'échantillons de #régolithe et de roches lunaires, couplée à l'analyse des #gaz en surface par l'instrument #DORN, a permis aux scientifiques impliqués dans la mission #ChangE6 d'identifier la survenue de deux épisodes volcaniques sur la face cachée de la Lune, il y a 4,2 et 2,8 milliards d’années. Pour mémoire, les échantillons rapportés par les missions #Apollo et #Luna de la face visible de notre satellite attestent d'un seul événement volcanique, daté de plus de 3 milliards d'années.

D'autres analyses sont en cours, qui permettront « d’affiner des observations antérieures réalisées par #télédétection qui ont montré que la face cachée de la Lune est différente, en termes de #géophysique (différences d’épaisseur de la croûte, par exemple) et de composition chimique et minéralogique des roches, de celle de la face visible », explique Pierre-Yves Meslin, astronome à l'IRAP.

Info+ : polytechnique-insights.com/tri

“we report two newly recognized episodes of basaltic volcanism with Pb-Pb dating for basalt fragments returned by the #Change6 mission. One high-Al basalt fragment dated at 4,203 ± 4 million years ago (Ma) has a source 238U/204Pb ratio (µ value) of ~1,620, implying a KREEP-rich (K, rare earth elements, and P) source for this oldest-known occurrence of #basaltic #volcanism among returned samples”

🌘🌋

#lunar / #moon / #volcano <nature.com/articles/s41586-024>

NatureLunar farside volcanism 2.8 billion years ago from Chang’e-6 basalts - NatureUnravelling the volcanic history of the enigmatic lunar farside is essential for understanding the hemispheric dichotomy of the Moon1-3. Cratering chronology established for the lunar nearside has been used to suggest long-lived volcanism on the farside of the Moon3,4, but without sample verification. Here we report two newly recognized episodes of basaltic volcanism with Pb-Pb dating for basalt fragments returned by the Chang’e-6 mission. One high-Al basalt fragment dated at 4,203 ± 4 million years ago (Ma) has a source 238U/204Pb ratio (µ value) of ~1,620, implying a KREEP-rich (K, rare earth elements, and P) source for this oldest-known occurrence of basaltic volcanism among returned samples. The main volcanic episode of the Chang’e-6 basalt documents a surprisingly young eruption age of 2,807 ± 3 Ma, which is not recognized from the nearside of the Moon. The initial Pb isotope compositions of these younger basalts indicate derivation from a source with a µ value of ~360, indicating a KREEP-poor mantle source. Mare volcanism on the lunar farside thus persisted for >1.4 billion years even with a shift to a source depleted in heat-producing elements. The consistency between the 2.8-billion-year basalt age and its crater-counting age indicates that the cratering chronology model established for the lunar nearside is also applicable to the farside of the Moon.

Samples obtained by #China's #Change6 #spacecraft show #moon's ancient #volcanism
Researchers said the soil brought back from the Chang'e-6 landing site contained fragments of volcanic rock - #basalt - dating to 4.2 billion years ago and to 2.8 billion years ago. This points to a long period of volcanic activity - at least 1.4 billion years - on the far side during the first half of the moon's history, when it was a more dynamic world than it is today.
yahoo.com/news/samples-obtaine

Yahoo News · Samples obtained by Chinese spacecraft show moon's ancient volcanismBy Will Dunham

🚀 Exciting news from the moon! 🌕 New research reveals that the far side of the moon, previously shrouded in mystery, once hosted erupting volcanoes just like its near side. 🌋 The findings come from samples collected by China's Chang'e-6 mission, which returned volcanic rock fragments dating back over 4 billion years! 🧑‍🔬 This discovery sheds light on the moon's geological past and raises questions about its evolution. #MoonMysteries #ChangE6 #LunarVolcanism

🔗 apnews.com/article/moon-volcan