Chang'e-4 farside landing mission Options

[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

[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:



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.



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.

[marsbug]

In English 'gel' is something that is mostly liquid by weight, but behaves much like a solid due to a scaffold of long molecules runningthrough it... My memory of that definition may be off but my point it is that in English that word refers to a specific state of matter. Is it possible that, in Chinese, the word or phrase is more nubulously defined, or more descriptive of appearance than material state? I can imagine impact glass looks my gel like. I could also imagine a 'glass gel' of an impure glassy (by which I just mean non crystalline) material mixed with crystalline materials that might qualify as 'gel like' in another language, or specific context.

[dudley]

The Chinese language appears to have distinct, specific words for both 'glass' and 'gel'--' boli' and 'ning jiao' respectively. They seem to mean the same, specific things that we do, when we use the words 'glass' and 'gel'.

[Phil Stooke]

Nevertheless, this report is not from scientists but via a journalist or media outreach person working with the mission. Blobs of impact glass were seen by every Apollo mission and there is no other reasonable interpretation of this, as far as I am concerned. We may have to wait for a journal paper to know more, maybe in a few months.

Phil

[nprev]

Agreed.

Furthermore, the difficulties of translation from Chinese dialects to English and vice versa are many, and that fact is rather well-known. Those become compounded if idiom is involved, or even many adjectives. But this case doesn't really seem that complicated. I can easily see how amorphous melt glass might be described as gel-like in appearance.

Bottom line is no, Chang'e-4 has not found jelly on the Moon.

[atomoid]

We'll have to wait. For now im holding out hope for some forbidden moon gummies, even if moon pie bites may be s'more fun