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Unmanned Spaceflight.com > Earth & Moon > Lunar Exploration > Chang'e program
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Phil Stooke
Only the first half of the 3rd day, March 1 to 3, followed by the noon siesta we are in right now. They probably took quite a bit of that time to adjust the position of the rover to get the fixed field of view of the instrument pointing at the rock. And actually we don't know this is the only rock they have analyzed in these last few days.

The original Yutu only used the instrument on soils so pointing was not such an issue. It was heading for some light-toned rocks on the rim of the crater just north of the lander when the rover stopped moving, so the science team may have been planning a rock analysis that never happened.

Phil
Paolo
QUOTE (Phil Stooke @ Mar 4 2019, 07:14 PM) *
New images in a post on Weibo.


It does not work for me. I land on the weibo login page
Hungry4info
I occasionally have the same trouble. Here are the two referenced images (not modified, the image quality really is that low, clearly the post on Weibo was not the true original images).
Phil Stooke
I don't know what happened with the above link, but it works fine for me.

Andrew Jones tweeted this:


https://twitter.com/AJ_FI/status/1104269021829128192


- giving some new images and a link to the source. The new images include a half-panorama taken at the end of lunar day 2, showing a group of small rocks which became the target of activities on the 3rd lunar day. If you go through the source you can piece it together: early in day 3 Yutu 2 moved on a dogleg path towards the rocks to put the VNIS (Visible and Near-Infrared Spectrometer) field of view on a small rock. The first attempt had the field of view just off the rock (Andrew did not reproduce that image, you have to go to the source to see it). The rover turned slightly and moved forwards and now the FOV was correctly placed. That takes us back to the images posted above.

Today, March 10th, Yutu 2 is waking up after a noontime nap.

Here is the panorama - patched with bits from the other images to cover sun glints etc. - and reprojected to show the area. My orientation might be slightly off but should not be too bad.

Phil

Click to view attachment

Phil Stooke
This is the image showing the VNIS image that missed the target.

Phil

Click to view attachment
John Moore
Third lunar night begins approximately on March 14, 2.30 UT, leading later to the fourth lunar day beginning approximately on 28 March 22.30 UT.

Note, above dates are related to terminator times over the landing site, not sleep-times/awakening-times of the Lander/Rover, which usually involves a day or two before or after the terminator dates occur.
kenny
Nice summary of current status of Chang'e-4 here, as Yutu-2 attains its design lifetime...

SpaceNews Chang'e-4
Phil Stooke
https://twitter.com/AJ_FI/status/1110035767697567746

Andrew Jones tweets a Chinese map and a nice picture of tracks. That was one of several track images shown in a presentation by Xiao Long at LPSC. I spoke to Long before his talk and he asked where I got the map information, as he didn't have access to it. I showed him the informal sites I had information from. In his talk he showed a redrawn version of my map! This new map solves that problem for Long, a proper Chinese map. I hope we will see this on a regular basis. Next I hope to see a few names for craters along the path.

Phil
Phil Stooke
Here's another Chinese forum page:

https://club.6parkbbs.com/life2/index.php?a...mp;tid=15228936

This is notable for a very early traverse plan. A hexagon around the lander, about 10 m on each side. They could follow either the clockwise or counterclockwise paths around the lander, photographing it from the vertices of the hexagon before departing. The counterclockwise path is blocked by large craters so the clockwise path was adopted, but modified so there was no imaging from D, north of the lander. This is exactly like the original CE3 - Yutu plan, but flipped north-south. This time I am adding the map here:

Click to view attachment
Hungry4info
A paper in Nature that I can't access has some images.
https://www.nature.com/articles/s41561-019-0341-7

This tweet has the images attached, but there's not a lot of context.

djellison
The paper itself contains nothing of merit beyond those images really.
Phil Stooke
I agree, just a summary of what the mission will do (at the 'uncover the secrets of the far side' level, not a day to day plan), not what it has done except for the nice new images.

Weibo has this story today:

https://www.weibo.com/ttarticle/p/show?id=2...355633053836186

(Thanks to Andrew Jones for tweeting the link). It has new images, very compressed, including this one:

Click to view attachment Click to view attachment

The hills show it was pointing north. The light shows it was taken at sunset, not dawn on day 4.

Phil
fredk
QUOTE (Hungry4info @ Mar 29 2019, 08:30 PM) *
This tweet has the images attached, but there's not a lot of context.

In the upper right image (the one at very low phase angle) does the large rock near bottom have a blast shadow from landing? The short paper says nothing about it.
Phil Stooke
No, the short paper says nothing at all, really. But I would be surprised if this is anything other than an internal reflection in the optics. We don't know where the rock is but it would have to be pretty close to the lander to present anything like a blast shadow. The location and shape are a BIG coincidence if I am right.

Phil

Phil Stooke
Andrew Jones tweets about an update on Weibo:

https://twitter.com/AJ_FI/status/1115508152487829504

Two images are attached to his tweet. Here I try to locate them:

Click to view attachment

The view to the northwest has evening lighting, and must have been taken at the end of lunar day 3. The other image showing a crater on the inner wall of an older crater is probably pointing northeast as I show it with white lines, and if so it is taken with morning illumination on lunar day 4.

Phil
Phil Stooke
This Weibo article:

https://www.weibo.com/ttarticle/p/show?id=2...360195798102342

reports on the end of lunar day 4 - Yutu 2 just shut down - and includes an image of two craters. Total distance now 179 m, so only another 8 m after the noon break. That probably means more work on nearby rocks or other targets. The same article reports on Beresheet.

Phil
Phil Stooke
No word yet on details of the 4th lunar day activities. I will save any map updates until I actually know something. However, the first data release from the radio astronomy experiment has done now, though only to the foreign partners, not to the public. Maybe other information will be coming soon (I am always an optimist).

Phil
Phil Stooke
Yutu 2 should be just about waking up for Lunar Day 5. Andrew Jones has tweeted a newly released image:

https://twitter.com/AJ_FI/status/1122025757516226561

Which I have roughly reprojected:

Click to view attachment

I am only guessing the orientation, where the pattern of tracks and the crater seem to match the last few drives on the most recently released route map from China (and the basis for my last update). If that is correct the image was taken with a fairly high sun a few days after sunrise on the 4th day, and the rover had not moved far at that point. It might have made a very small move or turned in place to put a target in view of its VNIS, but it has not moved far. But my guess might not be correct.

Phil
Phil Stooke
Another tweet by Andrew Jones with 2 images:

https://twitter.com/AJ_FI/status/1122455703103389696


One image superficially resembles the previous one, but it's not the same place. Here it is projected in two different versions, but the orientation may not be correct. I should be able to figure out where this is but I'm not having any luck so far.

Phil

Click to view attachment Click to view attachment
Phil Stooke
http://news.sciencenet.cn/htmlnews/2019/5/426119.shtm

This Chinese science news site says the total drive after day 5 is 190.7 m.

Andrew Jones has tweeted two new images:

https://twitter.com/AJ_FI/status/1127074091767406592

New results are supposed to be published next week, so I hope there will be enough information to update the map.

EDIT: one of the new images tweeted by Andrew Jones shows tracks and, in the top right corner where the logo is inserted, a little cluster of rocks. I think they are the rocks examined early on day 3, the tracks were made later in day 3 and the image is from the morning of day 4, based on lighting. The tracks in the previous post are still not identified (by me at least).

Phil
Paolo
That was quick... the first results from CE4 were published today in Nature:

Chang’E-4 initial spectroscopic identification of lunar far-side mantle-derived materials

and an explanatory article:
The Moon’s mantle unveiled
Phil Stooke
This article:

https://media.weibo.cn/article?id=2309404372965893514367

includes this image:

Click to view attachment

It shows a panorama projected into map form using a stereo topographic model to remove distortions - the black areas are hidden from the camera. A yellow dot is a science target, and red circles are craters to be avoided.

I have matched this with LRO images to confirm that it is from the end of lunar day 3, planning the science target work for day 4.

Phil
Phil Stooke
As lunar day 6 nears its end, no specific news but I am hearing that Yutu 2 has exceeded 200 m total distance. Looking for confirmation.

Phil
Phil Stooke
https://twitter.com/AJ_FI/status/1137933968584712192

Andrew Jones tweets about the end of day 6. 213 m total drive, 22 m in day 6. He tweets two pictures, and the one which shows a larger crater in the foreground is looking south-southwest (you can just see part of the rim at the very top of the image to help locate it). Knowing the direction we can see it has morning lighting, presumably from early in day 6. Here is a reprojected view:

Click to view attachment

That crater can be identified in the map, south of the 5th night location in my map.

Phil
Phil Stooke
Looking roughly east, here is a composite of track images from the last few releases.

Phil

Click to view attachment
Phil Stooke
Woohoo! (to coin a phrase). Check this out:

https://www.hou.usra.edu/meetings/planetdat...19/pdf/7030.pdf

An abstract for the Planetary Data meeting with a map of Yutu 2's path and other information.

Phil

Phil Stooke
Meeting abstracts are here:

https://www.hou.usra.edu/meetings/planetdat...ram.htm#sess101

Phil
Phil Stooke
This is the map from the abstract (hopefully considered 'fair use' for educational purposes). It is an excellent illustration of how the rover is driven, not with a 'joystick' controller and live (slow-frame) TV like the Lunokhods, but by mapping a safe route from end-of-drive images like the various Mars rovers. Sites are labelled, so I will be updating the route map soon.

Phil

Click to view attachment
John Moore
Below, an attempt to match the doughnut track positions to Phil's map. But don't take them as literal, as with most tracks, they all look the same, so open to correction (it all has to do with viewing/estimating the angles between each doughnut track - some approach angles under 90 degrees, others over 90, not to mention the paths taken, where some are straight-like, some curvable).

John
Phil Stooke
That looks good, John.

Several new images were tweeted by Andrew Jones.

https://twitter.com/AJ_FI/status/1143769296973291521


Here I have reprojected them to make it easier for me to compare with a map, but so far I don't have good matches to locations for them. They suggest that the rover moved a bit to the west and then turned south during day 6 (so a map revision is needed), but I don't know enough to draw the route yet.

The article linked by Andrew says (according to Google Translate) that there were control problems during day 6 caused - apparently - by a single bit flip error on a chip. The Mars rovers have seen these occasionally and recovered. They are caused by cosmic ray strikes. Yutu 2 has been recovered successfully.

Click to view attachment Click to view attachment Click to view attachment

EDIT: I replaced the middle image with a different version. The orientation is changed, but please bear in mind that these Hazcam images have a wider field of view than I show here.
John Moore
When I first saw the left-most image, Phil, I immediately thought 'Oh, that doesn't look good - some kind of surface-gripping struggle going on there.' But then thought that perhaps the rover was just doing more than one pivot on its axis as it planned its next route.

Btw, the doughnut images are probably wrong, as while the date they appear publicly are always out by several earth days to weeks, the actual lunar day date that they were taken is tricky to pin down (of course, CLEP, has that data).

John
charborob
Two images of the lunar surface on the CNSA page.
Phil Stooke
Andrew Jones tweets two new images:

https://twitter.com/AJ_FI/status/1148511189216956416

They can be fitted together to make a mini-panorama:

Click to view attachment

(here with some contrast enhancement).

And that can be roughly reprojected to give a more map-like view:

Click to view attachment

The lighting is around noon, so the rover may have travelled further since they were taken. No details on the distance travelled yet.

Phil

Phil Stooke
That last view with the 6th night location shown.

Phil

Click to view attachment
Phil Stooke
A new paper on topo mapping of the landing site:

http://www.pmrslab.cn/publications/publica...3-1383-2019.pdf

Here is a very small panorama from it (I have cleaned up some glare in it):

Click to view attachment

and a circular version for mapping:

Click to view attachment

These are from the end of lunar day 1.

Phil
Phil Stooke
This 'rover driving diary':

https://mp.weixin.qq.com/s/ULbPx6V957kW9CtR_cTU5g"" target="_blank">https://mp.weixin.qq.com/s/ULbPx6V957kW9CtR_cTU5g</a>


has some new images in it from day 7. Andrew Jones had tweeted some of them. The impression I have is that the rover did not move very far after its lunch break in day 7, so the estimate in my last map was overly optimistic. The drive was 25 m in day 7.

Here is a reprojected version of a mini-panorama from the link:

Click to view attachment

It is similar to the one I posted above but shows a little more progress, and the rover shadow at left shows it is taken with afternoon lighting.

There are also two sun-struck images, which can be fitted together like this:

Click to view attachment


The view is to the northwest (showing the central peak) near sunset, presumably on day 7.

Phil
Phil Stooke
Daniel Estevez has an analysis of the Longjiang 2 impact expected on 31 July:

https://destevez.net/2019/07/dslwp-b-mission-end-prediction/

It will crash near 15.5 north, 157.5 east, SE of Mare Moscoviense and about 300 km north of the Lunar Orbiter 1 impact site.

Phil
John Moore
Looks like somewhere northeast of Van Gent T.

John

charborob
Two images on the CNSA webpage, presumably taken on lunar day 8: http://www.cnsa.gov.cn/n6759533/c6807005/content.html
Paolo
meanwhile, DSLWP-B has crashed on the moon, as expected
https://twitter.com/cgbassa/status/1156575266153648128

QUOTE
There is a new crater on the Moon... We are already 5 minutes past the moment DSLWP-B would've appeared from behind the Moon if it had not crashed. The fact that we are no longer receiving signals means it has impacted the lunar surface. RIP DSLWP-B.
Phil Stooke
A map of the impact area. The ellipse does not represent the formal uncertainty, it just indicates the approximate area and the direction of approach. I am assuming that Daniel Estevez's analysis did not take into account actual topography and just assumed a spherical Moon, so the along-track dispersion could be larger than this suggests.

Phil

Click to view attachment
Phil Stooke
https://twitter.com/AJ_FI/status/1159087623882903552

Andrew Jones tweets a drive distance of 33 m and a total of 271 m for day 8 (I have to work really hard not to write 'sol 8'). Two images are released, one showing tracks, the other taken with a high sun and showing bright crater rims. It looks southwest. The big crater with a few visible blocks might be the large sharp-rimmed crater shown in the latest route map, but I am not sure yet. If it is, most of the 33 m must have been driven early in the lunar day and only a bit after this was taken. I think. More information might overturn my speculations.

Here is the crater image in a rough perspective view:

Click to view attachment

Phil
Phil Stooke
A very detailed analysis of the Longjiang 2 impact location:

https://destevez.net/2019/08/trying-to-find...p-b-crash-site/

Phil
John Moore
Was close - initially posted on UMSF 29 July, 2019, 01.23pm
Below, an attempt of impact location according to Estevez's grayscale image from this article.




John
Phil Stooke
There is a drive log for lunar day 8 HERE.

(That's a horrible URL, there must be a more direct way to link to the site).

Yutu 2 drove mostly to the west but turned off the path, probably to the southwest, to investigate a small very fresh crater which had an unusual object in or beside it. Sounds like a blob of impact glass. Then they backed up a bit, away from the crater.

I got this from here:

https://twitter.com/zengxingguo


Phil
Phil Stooke
This is a composite of several images from the above driver's blog, reprojected very roughly to give a picture of the recent travels.

Click to view attachment

Phil
Phil Stooke
There is a newly accepted paper in Geophysical Research Letters from Hu et al., on VNIS compositions at six sites over the first two lunar days. This builds on the paper on day 1 results which came out earlier. Bottom line is that the sampled materials are probably from the South Pole - Aitken basin impact melt sheet rather than basin ejecta.

Phil
Explorer1
A bit more detail on the small impact crater and the detour here: https://www.space.com/china-far-side-moon-r...-substance.html

Might be impact glass, indeed!
dudley
It seems very likely that the Chinese scientists would already know of natural glass, caused by meteorite impacts. Why, then, refer to this unidentified substance as 'gel-like'? They presumably had grounds for doing so. Moldavites and Libyan desert glass are usually green or yellow-green in color and not transparent. Perhaps this mysterious substance on the Moon was of some other color, or transparent, as gels often are.
Explorer1
My bet is something got lost in translation, rather than it being an actual gel as understood on earth.
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