Author Topic: Chang'e-4 lunar operations (Read 248770 times)

Phil Stooke · « **Reply #220 on:** 01/08/2019 06:36 am »

Also, we just passed New Moon when the Moon is very close to the Sun in the sky and radio interference might be a bit of an issue. But the siesta is the biggest reason, I'm sure. However, I think some lander terrain camera images are on the ground. Hopefully one or two will be released.

Satori · « **Reply #221 on:** 01/08/2019 02:14 pm »

China Focus: Relay satellite Queqiao plays key role in exploring moon's far side.

Steven Pietrobon · « **Reply #222 on:** 01/09/2019 03:32 am »

The interesting bit from the article.

"We will let Queqiao work as long as possible. It could also provide communication for probes from other countries if they intend to explore the moon's far side within the lifetime of the satellite," said Ye Peijian, an academician of the Chinese Academy of Sciences and a senior space expert.

Blackstar · « **Reply #223 on:** 01/09/2019 05:05 am »

Quote from: Steven Pietrobon on 01/09/2019 03:32 am

The interesting bit from the article.

"We will let Queqiao work as long as possible. It could also provide communication for probes from other countries if they intend to explore the moon's far side within the lifetime of the satellite," said Ye Peijian, an academician of the Chinese Academy of Sciences and a senior space expert.

Yes, that is a remarkably clever move. It gives China a unique asset to offer to potential partners.

clongton · « **Reply #224 on:** 01/09/2019 02:40 pm »

Quote from: Blackstar on 01/09/2019 05:05 am

Quote from: Steven Pietrobon on 01/09/2019 03:32 am
The interesting bit from the article.

"We will let Queqiao work as long as possible. It could also provide communication for probes from other countries if they intend to explore the moon's far side within the lifetime of the satellite," said Ye Peijian, an academician of the Chinese Academy of Sciences and a senior space expert.

Yes, that is a remarkably clever move. It gives China a unique asset to offer to potential partners.

Yea. It's something that people here have been advocating for NASA to do for a very long time but afaict NASA hasn't taken it seriously because it was an asset they had no use for. However that is exactly the kind of asset that would be part of a long term infrastructure plan for HSF in and around cis-lunar space. But because of ever-changing directions from various administrations and Congress pulling the purse strings to satisfy pork needs on the home front, NASA cannot create, let alone actually execute any such long term planning. Everything has to happen in the near term to satisfy 2 and 4 year election cycles. That really hurts NASA's awesome potential on that front. But I digress.

mcgyver · « **Reply #225 on:** 01/09/2019 03:20 pm »

Scientists and politicians have different visions of the reality.

Phil Stooke · « **Reply #226 on:** 01/09/2019 06:30 pm »

https://www.weibo.com/ttarticle/p/show?id=2309404326646026003185

This article was linked from the CLEP Weibo account. It briefly summarizes the current situation and the reason for taking a 'siesta' (if I can indulge in a bit of cultural fusion). Link to it in Chrome to get a rough translation.

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.

Olaf · « **Reply #227 on:** 01/10/2019 08:24 am »

https://twitter.com/AJ_FI/status/1083292604408705024

Olaf · « **Reply #228 on:** 01/10/2019 12:17 pm »

https://gbtimes.com/yutu-2-rover-reawakens-after-midday-nap-to-continue-change-4-objectives
Yutu-2 rover reawakens after midday nap to continue Chang'e-4 objectives

Satori · « **Reply #229 on:** 01/10/2019 03:38 pm »

Int'l payloads on Chang'e-4 start operation.

Satori · « **Reply #230 on:** 01/10/2019 03:40 pm »

China Focus: China welcomes world's scientists to collaborate in lunar exploration.

wahaha · « **Reply #231 on:** 01/11/2019 12:23 am »

wahaha · « **Reply #232 on:** 01/11/2019 12:32 am »

A better one

Phil Stooke · « **Reply #233 on:** 01/11/2019 02:01 am »

This immediately makes the landing site very clear:

Blackstar · « **Reply #234 on:** 01/11/2019 03:45 am »

Quote from: Satori on 01/10/2019 03:40 pm

China Focus: China welcomes world's scientists to collaborate in lunar exploration.

"The scientists of the Lunar Reconnaissance Orbiter (LRO) of NASA have also cooperated with the team of the Chang'e-4 mission to study the landing of the Chang'e-4 probe, according to CNSA.
The U.S. side has offered the orbital data of LRO and the Chinese side has provided the landing timing and location, said CNSA."

This is interesting but also very puzzling.

Before the CE3 landing, CNSA and NASA had an agreement: NASA would share LRO data and even help the Chinese interpret it, and in return, CNSA would provide the time and location of the CE3 landing engine burn so that NASA could monitor it with LADEE and determine how much gas was being added to the lunar exosphere. NASA provided the information and then the Chinese reneged on the deal, not providing the information that they had agreed to provide. This was not received well in the U.S. among the very few people who were aware of it, because NASA had to gain special permission from Congress to engage in that cooperative effort, and afterwards it looked like China had taken advantage of NASA.

https://spacenews.com/foust-forward-the-challenges-to-chinese-space-cooperation/

(As an aside: I've discussed this with several business people who have done business with China and they have all experienced similar situations. China has proven to be unreliable as a partner.)

So I find it very hard to believe that NASA and CNSA had any kind of agreement prior to the CE4 landing, because NASA would have had to get permission from Congress again, and why should anybody trust the Chinese on this? Plus, there's no real value to knowing the time and location of the CE4 landing, because NASA no longer had LADEE in orbit to monitor it. Now maybe NASA could have tried to monitor the landing using LRO, but that seems doubtful.

One possibility is that CNSA simply used the publicly available LRO photos of the area, and then sent NASA a message with the time and location of the landing, but there was no actual agreement. Another possibility is that this account is greatly distorted and nothing like this actually happened.

Steven Pietrobon · « **Reply #235 on:** 01/11/2019 05:32 am »

Here's an enhanced version of the landing site. The large craters to the east might be interesting to investigate. Can anybody spot any mounds or boulders? All I can see are craters.