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Unmanned Spaceflight.com > Earth & Moon > Lunar Exploration > Chang'e program
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Phil Stooke
Thanks, Doug. This is Pan 30, 1 April 2019, in circular form (after a bit of cleaning up):

Click to view attachment

Comparison with the map shows it was taken at the same location as the end of day 4. Sunset was on 12 April but the rover was already at that location on 1 April after just one drive (I think) in the first 3 days after sunrise. Using arguments like these I am refining dates on the maps.

Phil
Phil Stooke
https://twitter.com/Yeqzids/status/1223647437300158464

This tweet (from one of our past students at Western) links to a big collection of PNG versions of the Chang'e 4 and Yutu 2 images, lots of goodies to play with.

Phil

Phil Stooke
https://www.hou.usra.edu/meetings/lpsc2020/pdf/2153.pdf

And this LPSC abstract (thanks to Andrew Jones for pointing it out to me) has a map of Yutu 2's travels with those site or panorama numbers I was trying to map earlier. I think this makes it clear they are some kind of observation number, not just full panoramas but also local mosaics (like the impact glass crater) and maybe other things. Some sites have lots of observations, accounting for the apparently missing numbers Doug mentioned.

Phil
Phil Stooke
A new paper in JGR-planets:

Lin, H., Xu, R., Yang, W., Lin, Y., Wei, Y., Hu, S., He, Z., Qiao, L. and Wan, W., In situ photometric experiment of lunar regolith with visible and near‐infrared imaging spectrometer onboard the Yutu‐2 lunar rover. Journal of Geophysical Research: Planets, p.e2019JE006076.

explains something about the multiple observations at one target in particular. From 29 March to 1 April the rover performed a photometric experiment with its VNIS, calibrating it under different viewing angles as the rover turned in place.

Phil

Huguet

Thanks Phil for the twitter link to the PCAM and TCAM images, i'm just having great fun working with then.

The Rover are taking blocks of images on a very nice pattern, on each stop position. This allow to create 3d models of position shots similar to laser Blocks. Then its just a matter of triangulating the "simulated laser blocks" and geting a very nice detailed terrain and objects models of Moon, Lander and Rover.


John Moore
While understanding parts of your graphic entirely, Huguet, which is excellent by the way, I do hope you will expand upon it in final description -- using the laser blocks.

I had a stab at what feature on the aerial view related to the 3D version...so forgive me if incorrect.

Looks like, the OUTER blocks begin from a western position from 48 to 61 east in the top-half of the image in a clockwise direction, and the bottom-half from a western position from 34 to 47 in a counter-clockwise direction.

The INNER blocks are different, in that they begin from a northern position - starting from 34 to 47 anti-clockwise, and from 48 to 61 clockwise.

John Moore

Huguet

Hi Jonh,

The only mapping sensor they send with the rover was the PCAM cameras, usualy they could get stereo pairs on the rover direction all the time, but this would limit the mapping area and could generate more black zones without mapping. The best way to map a terrain, by ground view, would be with laser blocks. Its very simple, you just need to change the laser position and take a 360o (or a bubble) cloud of points. Every cloud or block has a internal perfect geometry, we just need to find 3 common points beetween two blocks to triangulate one with the other, and continue this process with the other blocks.

They used this aproach with chang-e'4 rover. Simulating the laser blocks with angular photos with the stereo pcam cameras, inclinating the pcam support or using the rover rotation to expand the distance beetween the images, increasing the acuracy of each 3d block and avoiding black areas.

Within the 5 GB of pics provided of the PCAM cameras, we have lots of group of images to generate 3D blocks. All we need to do is the photogrammetry to generate 3d models of each group of pics, and deal with this 3d models as we would deal with laser blocks, finding 3 common points beetween then and triangulating. This will generate a model with a resolution of more or less 1 point / cm2 of the path of the rover, including the lander model. This full cloud will need to be geo-referenced, we can make this using some know moon points like the center of some craters.

I will isolate the blocks pics ids, the 3d blocks, a full cloud later and post here as RCS (Autocad), LAZ (Globalmapper) or PTS (Text File).
John Moore
Thanks again, Huguet...looks like 2D DEMs to 3D bubble DEMs...using laser block technology.

Perhaps, a 'Laser Block' DEM data resource, in the near future?

John Moore
Phil Stooke
https://www.mdpi.com/2072-4292/12/4/624/pdf

This paper is very interesting in itself but also relevant to these recent posts. Rover route planning, with lots of images.

Phil
John Moore
Phil, thanks for that PDF link.

The below animation was generated from the 24-bit greyscale image on page 8, so the quality could be improved on, however, I don't have access to the higher 16-bits. The crater, in the paper, is said to be 8.7 metres in diameter, and the resolution is of 0.02 metres. White areas in the centre of the crater are missing data points (not water-ice deposits tongue.gif ).

John Moore

atomoid
interesting report on subsurface, here from science news

Phil Stooke
Here:

http://www.leonarddavid.com/chinas-penetra...e-moon-finding/

is a nice article about the radar findings from veteran space reported Leonard David. But check out the pictures from mission control. Everyone's wearing a mask, as we might expect, but the screen behind them has a great panorama from some recent date with the route marked on it, and just legible are designations for the night locations, S14, S13, S12 and so on. Other sources have shown the first 3 night locations labelled S1, S2, S3 so we have a well established pattern. Intermediate stops are being labelled in various ways (LE00201, LE201, N201 etc.), always using the Roman alphabet (and Arabic numbers). For 201, the lunar day is the first digit, the stop for that day is the third digit. Still no evidence of crater names but I live in hope (so far).

Phil
Phil Stooke
https://mp.weixin.qq.com/s/uvyqkFUkrbh_mHbtZvEYBw

This link is to a post on day 15 of Yutu 2's mission. Open in something that will translate it for you if you need to. The story is that they were heading south to a prominent crater but have decided to turn northwest instead. 1800 m northwest of the rover is a patch of basalt which they want to investigate (it's buried under at least 40 m of ejecta where they are now). They hope to get there in a year or so, implying a huge increase in driving per lunar day and therefore less analysis along the way (presumably). First they have to drive around a large degraded crater about 150 m across and west of the current position (shown on my new map but more prominent in the images in the article).

Phil
John Moore
Below, a GLD100 (+LOLA) slope comparison.



The old Geological data doesn't yield that much

John Moore
Phil Stooke
Here is a very interesting forum thread on the Chinese 9ifly forum, full of details about the mission and (at the moment) being updated as needed.

http://www.9ifly.cn/thread-93232-1-1.html

Open in something that will translate it for you if you need to.

Yutu 2 just woke up for its 16th lunar day and exceeded the 400 m mark on its traverse.

Phil
Phil Stooke
I'm hearing 24.5 m during the 16th lunar day, 424.5 m total.

Phil
Phil Stooke
Here's an abstract for a poster at the next COSPAR meeting:

---------------------
43rd COSPAR Scientific Assembly 2020

Space Studies of the Earth-Moon System, Planets, and Small Bodies of the Solar System (cool.gif
Human and Robotic Exploration of Moon, Mars, and Asteroids (B0.2)
Consider as poster only.

LOW FREQUENCY RADIO SPECTROMETER ONBOARD THE LANDER OF
CHANG’E-4 MISSION

Xinying Zhu, zhuxy@bao.ac.cn
National Astronomical Observatories of Chinese Academy of Sciences, Beijing, China: Chinese
Academy of Sciences (CAS)
Jianjun Liu, liujj@nao.cas.cn
National Astronomical Observatories of Chinese Academy of Sciences, Beijing, China: Chinese
Academy of Sciences (CAS)
Yan Su, suyan@nao.cas.cn
National Astronomical Observatories of China, University of Chinese Academy of Sciences,
Beijing, China: Chinese Academy of Sciences (CAS)
Weibin Wen, wenwb@nao.cas.cn
National Astronomical Observatories of Chinese Academy of Sciences, Beijing, China: Chinese
Academy of Sciences (CAS)
Junduo Li, lijd@nao.cas.cn
National Astronomical Observatories of Chinese Academy of Sciences, Beijing, China: Chinese
Academy of Sciences (CAS)

Chang’e-4 mission is consisted of three parts –lunar lander, lunar rover and relay satellite. The
relay satellite nicknamed QUEQIAO was launched to the halo orbit of the Earth-Moon Lagrange
Point L2 at 21:25 UTC ,May 20th,2018,and the Chang’e-4 lunar lander and rover successfully
landed in Von Karman crater on the far side of moon at 02:26 UTC,Jan 3rd 2019.The Low
Frequency Radio Spectrometer (LFRS) is a scientific payload onboard Change-4 lunar lander.
The primary motivation for LFRS is to learn about the universe through VLF spectral window
which is the only part of the electromagnetic spectrum yet to be completely explored. LFRS
will provide situ measurements of low frequency(100kHz40MHz) radio phenomenon in the
far-side of moon first time in human history. The noise from the Chang’e-4 lunar lander itself
is very intense, thus all target’s radio emissions are hidden in this noise. A method is proposed
in order to suppress the significance interference from the lander. A short correct antenna was
installed very close to the Lander near the 5m long LFRS antenna. The signals received from
the correct antenna are almost the noise from the lander, because the short correct antenna is
not so sensitive as the 5m long antenna to the target’s radio emissions. The signals received
from 5m long antenna will be corrected by the signals received from short correct antenna to
suppress the interference from the lander.In order to evaluate the performance of the LFRS, a
series of ground experiments are carried out using the LFRS prototype model. The results after
EMI mitigation show that the lower limit detection level of LFRS may be 10􀀀18Wm 􀀀2Hz 􀀀1:


see more here:

https://www.cospar-assembly.org/
Phil Stooke
Lunar day 17 just ended and the total distance now is 448 m (rounding up), 23 m during that day.

Phil

https://www.weibo.com/ttarticle/p/show?id=2...499316386431055
Phil Stooke
New data!

http://moon.bao.ac.cn/pubMsg/detail-CE42EN.jsp
-------------------------------
Chang'e 4 second scientific data is released
28 April 2020

On 28 April 2020, the Ground Research and Application System of Chinese Lunar Exploration Project released the second scientific data of Chang'e 4. The Chang'e 4 achieved humanity's first soft landing and in-site detection on the far side of the Moon, on 3 January 2019. Until March 2020, the Rover (Yutu-2) already finish the 16th lunar day scientific exploration, and achieved breakthrough of double 400, it means that the rover survives over 400 days and travels over 400 meters on moon's far side. At present, it carried out the 17th lunar day scientific exploration.

The Ground Research and Application System of the Chinese Lunar Exploration Project released scientific data acquired by 4 scientific payloads onboard Chang'e-4 lander, rover(Yutu-2) during the 3rd and 4th lunar day. A total of 1,471 data files, with a total data volume of 7.18 GB are released.
--------------------------------

This will include the VNIS data for the rock I have noted a name for in the map thread. Qi Yuan, translated in a journal article as 'unexpected encounter' or perhaps 'lucky encounter', but showing up in Google translate versons of recent Chinese press articles as 'Pocahontas'. I don't know where that comes from, but I note that the CE5 T1 return capsule which was named 'little flyer' got translated as 'Dumbo' because that was the name given to the well-known flying elephant in China.

Phil
Xerxes
QUOTE (Phil Stooke @ May 8 2020, 07:16 PM) *
Qi Yuan, translated in a journal article as 'unexpected encounter' or perhaps 'lucky encounter', but showing up in Google translate versons of recent Chinese press articles as 'Pocahontas'. I don't know where that comes from


Feng Zhong Qi Yuan (風中奇緣) "An Unexpected Encounter amidst the Wind" is the Chinese name of the Disney movie called "Pocahontas" in English. It certainly highlights the dangers of using computer-assisted translation without due caution. I wonder, though, if the Chinese scientists are intentionally choosing punny names for their sites.
Phil Stooke
Thanks for that useful information.

https://www.weibo.com/ttarticle/p/show?id=2...505533557113267

This link is to the Weibo notification that Yutu 2 woke up a few days ago, on its 500th day on the Moon. A couple of nice pictures. Also we learn that because the communications systems are being upgraded for the upcoming Mars mission, Yutu 2 will not drive this month but will 'detect' in place. VNIS might make repeated observations under different lighting conditions (my speculation). LPR will probably not accomplish anything by repeated use in one place so may not be used. The neutral atom instrument may still get good results. The lander might be able to operate as usual. A small crater nearby will be the next study site when Yutu 2 moves again.

Phil
Phil Stooke
My thoughts about what might be done during the 18th day were completely off. Only the neutron and radiation detector on the lander was operated. But just about now the Sun is rising on the lander and rover, so if they are to be used this month they should start tomorrow. I had heard that the work on communications systems was nearly finished a while ago, so with any luck Yutu 2 will be busy soon. The task will be to investigate a nearby crater just a few meters away, so possibly not a lot of driving this month.

Phil
Phil Stooke
Yutu 2 is back at work on day 19. Two images were released here:

https://www.weibo.com/ttarticle/p/show?id=2...516092918759681

And they fit together like this:

Click to view attachment
Phil Stooke
Perspective projection (approximate) of the above to help map tracks.

Phil

Click to view attachment
Phil Stooke
New data from CE4 and Yutu 2:

----------------------------------
13 June 2020
On 13 June 2020, the Ground Research and Application System of Chinese Lunar Exploration Project released the third scientific data of Chang'e 4. The Chang'e 4 achieved humanity's first soft landing and in-site detection on the far side of the Moon, on 3 January 2019. Until June 2020, the Rover (Yutu-2) already finish the 18th lunar day scientific exploration, and travels 447.68 meters on moon's far side.

The Ground Research and Application System of the Chinese Lunar Exploration Project released scientific data acquired by 4 scientific payloads onboard Chang'e-4 lander, rover(Yutu-2) during the 5th and 6th lunar day. A total of 1096 data files, with a total data volume of 6.11GB are released.The data is described in detail in the product description.

Lander:
LFRS Level 2C scientific Data
Rover:
PCAM Level 2B Scientific Data
LPR Level 2B Scientific Data
VNIS Level 2B Scientific Data
The Ground Research and Application System is one of five major systems of Chinese Lunar Exploration Project, it responsible for the lunar exploration data receiving, processing, managing and releasing. The GRAS Moon and Planetary data center provide data services and technical support.

Our contact information: lpdc@nao.cas.cn
---------------------------------

http://moon.bao.ac.cn/pubMsg/detail-CE43EN.jsp



Phil
Phil Stooke
On the Chinese 9ifly forum a user has posted news about Yutu 2. Currently snoozing through its mid-day nap, but in the 3 days (June 15-17) before the break Yutu 2 examined a small crater which had been seen to have light-toned material in and around it. It turns out to be a regolith breccia, or what was sometimes called 'instant rock' regarding Apollo samples - regolith converted to a loosely bound 'rock' by shock or bits of impact glass. It was broken apart by the rover's wheels. After the break they will move on again. Only 5 m of travel in that morning work session, maneuvering around the little crater to get VNIS on it.

No pictures of it yet.


http://9ifly.spacety.com/forum.php?mod=vie...page=3#lastpost

Phil
Phil Stooke
https://www.weibo.com/ttarticle/p/show?id=2...704170131498#_0


This article describes the activities of Yutu 2 during the 19th lunar day. A picture of tracks in it is part of a larger panorama taken with roughly mid-day lighting, with images released earlier:


https://www.weibo.com/ttarticle/p/show?id=2...092918759681#_0

That report describes the start of work on day 19, so the latest image is not from the end of the day and is either taken just as work started on day 19 or (my guess) on day 17 around the time of the mid-day break.

Here is a composite image of the tracks at that time.

Phil

Click to view attachment
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