Chang'e-4 farside landing mission Options

[Explorer1]

This (English) article says they were powered down for sunset (i.e. the experiment would not go past lunar night).
https://news.cgtn.com/news/3d3d414f7949444d...54/share_p.html

Now it is night on the Moon and the temperature has dropped to nearly 180-degree centigrade below freezing. All the equipment has powered down, and the remaining seeds and animals will be gradually decomposed down to organic fundamentals.

[Phil Stooke]

OK, that's good. I had thought it was supposed to work through the lunar night with warmth and artificial light, though I know it piped in natural light during daylight. It does seem like a useful next step would be to allow longer operation on a future mission. Maybe that is more suited to polar missions, which we know are in the plan.

Phil

[wildespace]

What the landing site will look in early morning. High incidence angle (86.68 degrees) view from M178833263LC

[Phil Stooke]

I saw this picture tweeted on the 11th or 12th and then couldn't find it again to save it. Now I found it on this site (near the bottom):

http://py.qianlong.com/2019/0116/3064840.shtml


It is from the last position on the first lunar day, looking back on the tracks from that day's drive. Does anyone have a better version of it?

Phil

[kenny]

According to the Google image-matching search function, that is the only version of that image on the internet at the moment.
Google's best guess for the subject of that image is a River Clyde steamer !

[Huguet]

Yutu 2 will have a hard time avoiding all that craters, he will need to be making adjustments at almost every meter.

"From the images sent back from Chang'e 4, we can see the area surrounding the probe is dotted with craters of different sizes, and it's very difficult for the rover to drive in the region," explained Sun Zezhou, chief designer of the Chang'e 4 probe, according to Xinhua.

"We'll try to find the relatively safe areas and make a reasonable plan for the route of the rover based on the images taken by it," Sun said, adding, "we haven't found any insurmountable obstacle in the region."

[John Moore]

Looks like the top-left (squiggly) tracks are those where it stopped at the crater south (classic image, well-published at this stage), the rover did a 180 deg there (and more), and from the current image,
we're still looking back southwards as the Rover travelled north after two wheel-abouts (the Lander would be to the left - some several metres away).

Have a simulated image put together of the possible track, but it would have been poor to post.

The stopped-off position of the Rover is well within the lunar night-time -175 deg C temperatures now; waiting for further activation round the 28/29 Jan 2019. Fingers crossed.

[Phil Stooke]

This must be the first journal publication to come out of Chang'e 4 operations.... the DOI or title will lead you to the journal website, from which the paper, in English, can be downloaded free by anyone.

Phil

Di, K. C., Liu, Z. Q., Liu, B., Wan, W. H., Peng, M., Wang, Y. X., Gou, S., Yue, Z. Y., Xin, X., Jia, M. N. and Niu, S. L., 2019. Chang'e 4 lander localization based on multi-source data. Journal of Remote Sensing, v. 23, no. 1, pp. 177-184. DOI: 10.11834/jrs.2019015.


EDIT - here is the direct link to the journal site - I should have given it in the first place. Open in Chrome to translate.

http://www.jors.cn/jrs/ch/reader/view_abst...23-1-dikaichang

[Explorer1]

Looks like the lander and rover have woken up (judging from in the know social media accounts)! First science data release February 1st, apparently.

[charborob]

China's Chang'e-4 probe wakes up after first lunar night

[tolis]

One might wonder what is the contribution of the Earth, as a reflector of solar radiation, to lunar surface temperatures during the night
given that it has (i) 4x4 = 16 times more surface area, and (ii) a higher albedo than the Moon.

Anyone care to take up this exercise?

[ngunn]

One might wonder what is the contribution of the Earth, as a reflector of solar radiation, to lunar surface temperatures

An interesting question (though maybe not for a farside mission thread). To the reflected solar you would need to add the Earth's own thermal IR

[tolis]

An interesting question (though maybe not for a farside mission thread). To the reflected solar you would need to add the Earth's own thermal IR

Perhaps it is relevant to farside surface conditions insofar as the absence of the Earth in the sky would result in a lower nighttime temperature compared to the nearside (everything else being equal of course).

[ngunn]

OK I've done some very crude calculations based on black bodies and a nominal night surface temperature of 100K and I'm getting answers on the order of 0.1K.

[tolis]

Perhaps it is relevant to farside surface conditions insofar as the absence of the Earth in the sky would result in a lower nighttime temperature compared to the nearside (everything else being equal of course).

I'd say that is ~100x less than anything that would contribute to the nighttime temperature in a significant way.

Thanks.