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Unmanned Spaceflight.com > Earth & Moon > Lunar Exploration > Chang'e program
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mmatessa
Rover/no-rover
Click to view attachment
Steve G
The fact that you can see so far in the distance also indicates they have landed on a slight rise. Reminds me of the view from Stone Mountain on AS16.
Phil Stooke
This is my interpretation of the view to the south and the crater rim - south up in the LROC wide angle mosaic. The rim is about 40 km away and the highest peak is 3 km above the plains. I wouldn't say it's 100% certain but I like it better than an interpretation where the relief is a nearby crater. I agree with Steve G that we are on a local rise. Sadly, not enough detail in the middle distance for an exact location yet.

Tolis, you are right about the time determining the direction if you base it on shadows, but we know the landing was mid-morning.

Phil

Click to view attachment
John Moore
From mmatessa's animation, view of the shadows between each - Rover/No Rover - are shortening (note the change at the two small rocks nearby).

The sun is rising over the landed area, so, we must be viewing south as Phil suggests (if elsewise, looking northwards, the shadow changes would be reversed). The 'local sunset' mention may be due to that
of viewing the Moon from the Nearside, and anyways, why conduct a mission where the Sun is setting on the Farside, but more when it is rising - availing of its full potential to power-up (using the solar panels) the lander/rover overall.

John
Decepticon
The pictures posted by China's media look like false color?


Are they using different color filters to bring details out?

The moon looks more like mars in the media released images.
Phil Stooke
The surface images we have seen so far are just from a small monitoring camera - Chang'e 3 had several as well. The color is not accurate. We should soon see images from the much better cameras on the lander and rover, and they will have more realistic color.

Phil
jccwrt
Edit: nevermind, wrong year. That will teach me not to post on no sleep...
MahFL
QUOTE (jccwrt @ Jan 4 2019, 11:20 AM) *
Phil, here's a landing video you can probably use to pinpoint the landing site.

https://twitter.com/siyuan0zhao/status/1080...3315122177?s=19



That was the previous mission.
charborob
Yutu 2 moved a few meters (link):
Click to view attachment
Station
short animation concerning recent lunar events wink.gif


Station
I've just created the comparison of the Change 3 and 4 mission landing sites, well, first impression - very similar thanks to neighbouring small crater next to the lander's ramp wink.gif





Steve G
I'm amazed by the lack of rocks. We'll have to wait for a full panorama to see what the rest of the landing site is like.
neo56
Animation showing the deployment of Yutu 2 rover wheel.gif The second picture is a low resolution caption of Chinese TV.
I desaturated the 4 pictures to obtain more realistic colors of Moon surface.

Click to view attachment
Hungry4info
Anyone have any more information about this?

Edit: "After making the historic first tracks on the far side of the Moon, the Yutu-2 rover is going to enter "noon break" sleep mode til January 10, according to China's lunar program, as a precaution for high temperatures "
Phil Stooke
The first Yutu did exactly the same thing. They may also need to wait for the lander's camera to provide a good panorama to help plan the traverse.

Phil
charborob
QUOTE (Hungry4info @ Jan 4 2019, 11:48 AM) *
Anyone have any more information about this?

Edit: "After making the historic first tracks on the far side of the Moon, the Yutu-2 rover is going to enter "noon break" sleep mode til January 10, according to China's lunar program, as a precaution for high temperatures "


If you translate what is said in the link that I pointed to in my previous post (here it is again link), that's what it says:
"After that, the No. 4 will usher in the high temperature test of the Lunar New Year. The patrol (= Yutu 2 rover) will enter the “noon break” mode and is expected to wake up on January 10." (Google translation)
scalbers
Kind of neat to think of the rover taking a noon break when from the Earth's near-side perspective there's a new moon about that time.
Hungry4info
https://mp.weixin.qq.com/s/7Eg-h_25VBO6_QjJiO_QIg

The three five-metre antennas for the radio spectrometer have been deployed, the German LND neutron dosimeter is working, and the lander's terrain camera is sending back images.
Julius
Is the brown colour of lunar soil accurate? Is it dependent on lighting conditions on sun angle over horizon?
MahFL
QUOTE (Julius @ Jan 5 2019, 10:32 AM) *
Is the brown colour of lunar soil accurate? Is it dependent on lighting conditions on sun angle over horizon?


No, it's a low res simpler contex camera, the Moon is not red.
Webscientist
It is surreal to observe a surface devoid of any significant stones or rocks.
I imagine that the area is particular since we are in a large crater which appears quite flat from outer space. A large amount of volatile material resulting from the impact event must have filled the area. That's probably why, to a certain extent, the surface seems so cottony with a significant layer of dust (marking of the wheels).
I anticipate that we would have to dig to find the rocks.
I may be wrong but that's my impression at first sight.
Steve G
There are examples during the Apollo missions with few rocks and boulders. This very excellent Apollo 14 picture illustrates that. (I took the liberty to remove the extremely annoying Reseau crosses.)
wildespace
QUOTE (Phil Stooke @ Jan 3 2019, 08:22 AM) *
One other comment - the hills on the horizon in the one surface view we have are south of the lander. They are part of the rim of Von Karman, not the central peak. The direction of lighting in the image clearly shows that this must be looking south.

Phil

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I'd like to share this image posted at the Above Top Secret forum (where genuine discussion about space missions does happen), I think this guy did some excellent detective work:

Click to view attachment

(orbital image is from Chang'e 2)
Source: http://www.abovetopsecret.com/forum/thread...pg4#pid24085188
Phil Stooke
That confirms the interpretation given in post #103 above in this thread. I am really looking forward to seeing the full horizon. I don't know if the central peak will be visible but it might be. A small hill 10 km north might be as well.

Phil

Hungry4info
I took some of the frames Phil gave us from that control room footage and tried to stabilize the last couple of them, hoping to get an idea of where to look based off that. The imagery in the original video appears to move around in some areas and I'm not sure if this is just my own inability to follow the surface features or if the lander's autonomous hazard avoidance kicking in. Here's an animation of the last two frames, stabilized.

Click to view attachment

Based on this, and comparing it to imagery of the landing site, and knowing that there's a ~15-20ish metre crater just to the south of us, and assuming the lander continued all the way to the surface after the above animation without changing its course to avoid an obstacle, I think there's a good chance that the landing site is within a few metres of this location (marked with an X). Lat: -45.46738, Lon: 177.59876

Click to view attachment

It's not a perfect match, but I think it's a good candidate based on the above argument. I'm not very well satisfied with the difficulty in matching surface images seen in the rover deployment camera with what we see in this LROC image, but perhaps this can be explained with changes in illumination, and the difficulty in teasing out surface topology in a non-stereoscopic image at a more extreme viewing angle.
Phil Stooke
I have been trying to make a match without success. This is as good as anything I had come up with. I was looking a bit further west.


http://m.bldaily.com/china/news/p-373798.html

A picture near the bottom of this report shows tentative plans for the early operations. It exactly mirrors what was done by the previous rover. Drive around the lander and image it from several positions.

Phil

wildespace
After being deployed and travelling out for a short distance, Yutu-2 rover turned around 180 degrees for this photo:

Click to view attachment
(Source: http://www.abovetopsecret.com/forum/thread1228337/pg1 )

Hopefully, that means a photo of the lander coming up soon.
John Moore
About the size of the crater - just a bit of supposition: let's say the rover travelled some 12 metres from the lander, and stopped some 7 metres before the edge of the crater, and then assume that the
wingspan of the rover is some 2 metres in all (not sure, the stats are probably available somewhere), then that would put the size of the crater at about ~ 22 metres (+/- a metre) in diameter.
If it is, in approximate, round that estimate, that's a pretty small crater to be looking for if just using the Quick-Map alone pushed at its max zoom. Therefore, one might have to go down the NAC route.
scalbers
A somewhat similar view in Google Earth (switched to the moon).

Click to view attachment

Here is a video from Kaguya orbiting over Von Karman and Leibnitz, looking northward. Best view of the landing site is at about 0:27 into the video.

https://www.youtube.com/watch?v=D5oIoZkHYmY
JRehling
QUOTE (Webscientist @ Jan 5 2019, 06:49 AM) *
It is surreal to observe a surface devoid of any significant stones or rocks.
I imagine that the area is particular since we are in a large crater which appears quite flat from outer space.


Material on a lunar plain is almost always either the reworked result of an impact locally or material flung long-distance from other impact(s). The material flying due to each impact will have its own function of distribution of size vs. distance (with, as we see looking at ray craters, some radial variation as well). To see a rockless site just tells us that somewhere in that function for some impacts is dust without rocks. But I wouldn't expect that to be, necessarily, a function of the immediate local history – it could be telling us about the impacts that occurred tens and hundreds of km away, and in what sequence.
wildespace
QUOTE (JRehling @ Jan 7 2019, 10:23 PM) *
Material on a lunar plain is almost always either the reworked result of an impact locally or material flung long-distance from other impact(s). The material flying due to each impact will have its own function of distribution of size vs. distance (with, as we see looking at ray craters, some radial variation as well). To see a rockless site just tells us that somewhere in that function for some impacts is dust without rocks. But I wouldn't expect that to be, necessarily, a function of the immediate local history – it could be telling us about the impacts that occurred tens and hundreds of km away, and in what sequence.

Is the floor of Von Karman crater basically one big lava flood plain? That would explain the relative smoothness and the pits and groves observed in many place (collapsed lava channels?).

BTW, the nearby Leibnitz crater has some nice "lunar swirls", caused by local magnetic fields deflecting solar wind. I wonder if Von Karman crater had some localised magnetic activity.
threadworm
I'd forgotten I had an account here!

I made the image identifying the features in the background of the lander image smile.gif

I've also been busy downloading the Chang'e-2 data for the crater, and have made a 3D image of the hills in the distance, which you can get here:

China 3D model

Once extracted the open the index2.html file in either Microsoft Edge of Firefox (it won't work in Chrome). The base DEM layer is 20m resolution, and the photographic layer is the 7m resolution georectified (selenorectified?) on the 20m image. Here's a view from it:



I also did one from the Kaguya data:

Japan 3D model

same process for opening but this time the file is called index.html

Happy exploring smile.gif
Phil Stooke
Very nice!

I have been going nuts, or as my kids might say, more nuts, trying to find the site in pre-landing LRO images. Not easy when we have so little to compare with the LRO image. There was supposed to be a new LRO image on about the 6th, but possibly it missed the site (???). This article:

https://www.businessinsider.com/china-far-s...site-map-2019-1

says we have to wait until the end of the month.

For a while I thought I had a great clue. This tweet:

Click to view attachment

(Quanzhi was one of our students) shows somebody's idea of where the rover might go in the first week or so. Enlarging the middle of it we find this map:

Click to view attachment

For a while I thought the background might be a mission map made from descent images and I wasted many an hour looking for that pattern of craters. Then it dawned on me - it's the Chang'e 3 site flipped north-south! So still no idea.

Phil
Phil Stooke
https://www.weibo.com/ttarticle/p/show?id=2...326646026003185

This article was linked from the CLEP Weibo account. Link to it in Chrome to get a rough translation. It does not have much new in it but talks about the reason for taking a break in the middle of the day, to protect components from overheating. It confirms the lander is continuing to operate.

Chang'e 3 and Yutu did the same thing - a nap in the middle of the first day as a precaution against the noon heat. And it did it at the same place, after the second drive. If my memory is correct they did not plan to do this in the second day, but that is roughly when Yuyu stopped working. At the time I thought it might have been a heat-related problem, but we know now that it was an electrical fault instead. So it will be interesting to see if they do that again in lunar day 2.

The Lunokhods also took breaks around noon, but that was more to do with visibility for driving.

Phil
Phil Stooke
At last! They are great. Here's a circular version in my geometry. Much more on the horizon than I expected.

Phil

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Phil Stooke
And that takes us immediately to the landing site:

Click to view attachment

Phil
charborob
High resolution panorama:
http://www.cnsa.gov.cn/n6758823/n6758842/c...47/content.html
Explorer1
Wow! Right between those craters; my congratulations to the landing hazard avoidance team! Great rim views too.
Strange to think this is a landscape (unique in the solar system and probably the galaxy!) where Earth is never visible, yet its right next door....


Here's a rotated version of the vertical (Chinese-style?) panorama charbob posted:
neo56
I made a 360x180 version of the panorama and put it on RoundMe so that you can enjoy it in VR.
threadworm
Fantastic stuff - great detective work all round smile.gif

Just shows how deceptive distances are - I'd drawn some projection lines to the edge of the crater along the rover tracks and come up with a measurement of about 16m across for the crater immediately to the south but it looks to be more like 25m.

I've been looking at other sources for surface images and from what I can tell Japan's data is either too patchy or too dark to get a good look. India does have a swathe covering the crater but it is some way to the west of the landing zone, but if anyone wants to download it it's on orbit 3021 from the Chandrayaan site.

https://issdc.gov.in/CHBrowse/index.jsp

If you aren't registered you won't be able to browse to it, hence no direct link. It does at least show the craters to the north and south. There is another pass covering the far east of the crater, but frustratingly it's yet another one of those that is shown on their map but has no link and doesn't seem to be listed when you search for it.

Their own Chang'e-2 imagery barely catches the landing site.

Click to view attachment
threadworm
The full resolution video has now been released:

http://www.cnsa.gov.cn/n6758823/n6758838/c...57/content.html

Would have saved us a lot of time biggrin.gif

Here's a screenshot from the final stages.

Click to view attachment
wildespace
Yass! Now we see the landing site properly.

Here's 360-degree panorama from the master Andrew Bodrov: http://www.360cities.net/image/first-lunar...norama-change-4
GoneToPlaid
Attached is an enhanced LRO image of the Chang'e-4 landing site.

charborob
It looks like Yutu-2 made an almost 180-degree clockwise turn around the lander in order to photograph the side of it showing the Chinese flag:
http://www.cnsa.gov.cn/n6759533/c6805166/content.html
elakdawalla
Here is the mp4 of the landing. As far as I can tell, it contains all the full-resolution frames in order with numbers and time stamps. The computer I'm working on today choked when I tried to export all the frames using Photoshop, or I would've posted the whole archive for you. If someone is able to do that, I'd be glad to host them on our S3 server.

https://planetary.s3.amazonaws.com/assets/i...o-clep-cnsa.mp4
Credit: CNSA / CLEP
stevesliva
Amazing how fractal the cratering is. Well, amazing when I realize I have no idea of vertical height when looking straight down. Otherwise I suppose it's about to be expected.
neo56
QUOTE (Phil Stooke @ Jan 11 2019, 04:00 AM) *
And that takes us immediately to the landing site:


Phil, where did you download this picture? I'm on the QuickMap LROC website but the resolution is not as good as your picture.
charborob
I tried superposing Yutu-2's latest position on part of the panorama:
Click to view attachment
Phil Stooke
"Phil, where did you download this picture? I'm on the QuickMap LROC website but the resolution is not as good as your picture."

This is the original image data, not the version used in Quickmap which is not nearly as nice.

In Quickmap you can use a selection tool to outline a polygon, and get a list of all LRO images crossing that area (the list is not really the full data set, some frames are not included depending on when it was last updated). Each item in the list is a link to a page which lets you zoom in on the image or download the raw data. I download the CDR 16 bit version.

You can also search for LRO camera images from their website:

http://wms.lroc.asu.edu/lroc

That is more likely to have everything currently available.

My next step is to use the landing video images to supplement the LRO coverage.

Phil
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