Author Topic: LIVE: Chang'e-3 lunar probe and rover Lunar Landing December 14, 2013  (Read 470780 times)

Offline plutogno

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uhf satcom has reported detection of Yutu these past days
http://pjm.uhf-satcom.com/twtr/yutu_030215a.jpg

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So do we know what "functioning" actually means? Can it close up its systems for the night time? Do any of the moving parts work or are they all inactive and the only thing that works is the communications and electronics?

Offline Dalhousie

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Very nice paper in Science on results from Yutu's GPR and implications for the stratigraphy of Mare Imbrium  http://www.sciencemag.org/content/347/6227/1226.abstract
"There is nobody who is a bigger fan of sending robots to Mars than me... But I believe firmly that the best, the most comprehensive, the most successful exploration will be done by humans" Steve Squyres

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Offline Dalhousie

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That's from the Xiao paper, Figure 1.  Descent image with LROC inset
"There is nobody who is a bigger fan of sending robots to Mars than me... But I believe firmly that the best, the most comprehensive, the most successful exploration will be done by humans" Steve Squyres

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http://spacenews.com/chinas-mars-exploration-program-facing-delays/

"China is moving ahead with the sample return mission after the experience of its first lunar lander mission, Chang’e-3, which landed on the moon in December 2013. Despite technical problems with instruments on the lander, and mechanical problems that caused the lander’s small rover, Yutu, to stop moving about a month after landing, Wu said that mission was still viewed as a success.

Wu said that China had planned a second, similar lunar lander mission, called Chang’e-4, as a backup to Chang’e-3. With the success of Chang’e-3, however, China has postponed plans for Chang’e-4. “Because Chang’e-3 was so successful, the Chinese space agency doesn’t want to launch Chang’e-4 anymore” because there was little that could be learned from it, he said.

Instead, China now plans to fly an upgraded Chang’e-4 after the sample return mission. Wu said the revised Chang’e-4 mission, now scheduled for 2020, will use a more powerful launch vehicle that will allow for a heavier spacecraft and feature a landing in a different region of the moon, including possibly the far side.

Wu suggested that China would be open to international collaboration on instruments for that mission. “If you have good ideas and can provide instruments, you’re welcome to join Chang’e-4,” he said."

Offline Galactic Penguin SST

Is it about time that this thread get moved out of the live section and somewhere more appropriate? I don't know if that should be the science section or the Chinese section (although I cringe that the Chinese section is called "Chinese Launchers" and what is often discussed is not rockets but missions--the rocket is only important for about ten minutes and then the spacecraft can work for years).

I did hear some interesting information about this subject that I would like to add to the discussion. It's just that I don't think this mission is really appropriate for the live section. What do the rest of you think?

I agree with moving this one to the Science section and leave the launch thread where it is now (and I might even look into moving the Chang'e 1/2 threads as well, if others agree).  ;)
Chinese spaceflight is a cosmic riddle wrapped in a galactic mystery inside an orbital enigma... - (not) Winston Churchill

Offline Star One

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Is it about time that this thread get moved out of the live section and somewhere more appropriate? I don't know if that should be the science section or the Chinese section (although I cringe that the Chinese section is called "Chinese Launchers" and what is often discussed is not rockets but missions--the rocket is only important for about ten minutes and then the spacecraft can work for years).

I did hear some interesting information about this subject that I would like to add to the discussion. It's just that I don't think this mission is really appropriate for the live section. What do the rest of you think?

I agree with moving this one to the Science section and leave the launch thread where it is now (and I might even look into moving the Chang'e 1/2 threads as well, if others agree).  ;)

Seems a sensible course of action to me.

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I got some interesting information. It comes from some good sources, although it is possible that they may misunderstand some aspects of it.

So one interesting bit of information is that apparently space sciences (Earth science, heliophysics and astronomy) is under the auspices of the Chinese Academy of Sciences. I don't know how that is run, but it is essentially led by the scientists. However, planetary science is done by the same people who do their human spaceflight program, and that's under a separate organization, which I believe is part of the People's Liberation Army. That organization does not really have many scientists working for it.

The result of this setup (and I admit that it could be across the board for their programs but maybe it is more acute for planetary science) is that the engineers are in the driver's seat for planetary, not the scientists. Apparently with their lunar program the engineers made the decisions and only late in the process did they involve the scientists. The way it was told to me was that they essentially handed the data to the scientists and told them to make sense of it. Until then, the scientists were not involved. This is decidedly not how NASA and ESA do things and the Chinese think this is a problem and would like to find a way to put the scientists more in charge.

The other thing is that apparently the Chinese are going to reorganize and their planetary program is going to come under the CAS like the other space sciences. That will create an organization more like NASA's Science Mission Directorate (although I have no idea about their actual infrastructure and capabilities).

So one of the interesting things to me is that their lunar program has so far not really been run for scientific purposes but for engineering purposes. That's consistent with what I have assumed (and wrote about). But it was interesting to have this confirmed.

Hopefully the scientists will be heavily involved in selecting the landing site for CE-5. It would be good to have it go to a high value site rather than something the engineers want to do.

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This is mostly about the CE-5T1 mission, but I think it has relevance here. I see CE-3, 4, 5 and 5T1 to be all closely linked:


China’s Circumlunar Mission: New Details
By Leonard David
March 29th, 2015

http://www.leonarddavid.com/chinas-circumlunar-mission-new-details/


Offline Dalhousie

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So one of the interesting things to me is that their lunar program has so far not really been run for scientific purposes but for engineering purposes. That's consistent with what I have assumed (and wrote about). But it was interesting to have this confirmed.

Hopefully the scientists will be heavily involved in selecting the landing site for CE-5. It would be good to have it go to a high value site rather than something the engineers want to do.

There have been hundreds of papers published already so clearly science is a major part of the program.
"There is nobody who is a bigger fan of sending robots to Mars than me... But I believe firmly that the best, the most comprehensive, the most successful exploration will be done by humans" Steve Squyres

Offline plutogno

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So one interesting bit of information is that apparently space sciences (Earth science, heliophysics and astronomy) is under the auspices of the Chinese Academy of Sciences. I don't know how that is run, but it is essentially led by the scientists. However, planetary science is done by the same people who do their human spaceflight program, and that's under a separate organization, which I believe is part of the People's Liberation Army. That organization does not really have many scientists working for it.

there was an interesting article on the subject of who's in control of Chinese space science a few years ago in Nature:

"China forges ahead in space"
http://www.nature.com/news/china-forges-ahead-in-space-1.9359

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there was an interesting article on the subject of who's in control of Chinese space science a few years ago in Nature:

"China forges ahead in space"
http://www.nature.com/news/china-forges-ahead-in-space-1.9359

Yeah, so that 2011 article says this:

"And ambitious moves on the ground suggest that China will increasingly be able to develop and launch its probes without partnering with other nations. In July, the Chinese Academy of Sciences (CAS) in Beijing opened its National Space Science Center (NSSC), which will take charge of overall planning for the country’s space science. “China was a space country without a space science programme,” says Ji Wu, the centre’s director. Now that the CAS “has got government support to manage space science missions as a series”, he says, “it will lead to a new era for space science in China”.


The problem is that most space science except for planetary went over to the CAS (and their NSSC). But planetary stayed where it was, essentially co-existing with the human spaceflight program. The Chinese are planning to transfer it to the CAS sometime soon. But CE-3, for instance, was not developed/conceived by the CAS. That's what I was referring to up-thread. It's sort of two sides of the same coin: the planetary program as a whole is not run by the science organization, and the engineers (and not scientists) have been calling the shots for the planetary program.

Yeah, there may be a lot of papers published from those missions, but that is after the data is crunched, it does not mean that the scientists selected and designed the instruments and the mission.

Offline plutogno

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dunno how reliable this is, but concerning Yutu's problem this link states, in a Google translation:

Quote
Last year, when a fault, the rabbit has done a good mission. We speculate that a wire is small stones hurt, causing the battery voltage of 5 volts from the original down to 4.5 volts. We think a lot of ways, but still can not recover.

http://dzb.jinbaonet.com/html/2015-04/15/content_281970.htm

so it would appear that a rock clipped some wire, and the batteries (solar panels?) could no longer provide the necessary voltage.

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dunno how reliable this is, but concerning Yutu's problem this link states, in a Google translation:

Quote
Last year, when a fault, the rabbit has done a good mission. We speculate that a wire is small stones hurt, causing the battery voltage of 5 volts from the original down to 4.5 volts. We think a lot of ways, but still can not recover.

http://dzb.jinbaonet.com/html/2015-04/15/content_281970.htm

so it would appear that a rock clipped some wire, and the batteries (solar panels?) could no longer provide the necessary voltage.

Perhaps "small stones hurt" is "abraded by grit" ?

Offline luhai167

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dunno how reliable this is, but concerning Yutu's problem this link states, in a Google translation:

Quote
Last year, when a fault, the rabbit has done a good mission. We speculate that a wire is small stones hurt, causing the battery voltage of 5 volts from the original down to 4.5 volts. We think a lot of ways, but still can not recover.

http://dzb.jinbaonet.com/html/2015-04/15/content_281970.htm

so it would appear that a rock clipped some wire, and the batteries (solar panels?) could no longer provide the necessary voltage.

Perhaps "small stones hurt" is "abraded by grit" ?

去年出故障的时候,玉兔已经很好地完成了使命。我们推测,可能是一根导线被小石头伤到了,导致电池电压从原来的5伏降到了4.5伏以下。我们想了很多办法,但还是不能恢复。

No, the original article clearly says a wire is suspected of being damaged by a small rock.  If it grit, they will use the character 沙.

Looks like the power system need more redundancy.


Also the interesting about Chang'e 4 in the article is that C4 will involve more risk taking and perform more valuable tasks compared to C3, in the same way C2 did compare to C1. So my guess is that it will be a primarily a science mission rather than a engineer validation mission. Would be interesting see what they come up with.

« Last Edit: 05/29/2015 05:42 AM by luhai167 »

Offline savuporo

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I was surprised to read, catching up to some topics, that Yutu is still alive and talking.

March 9, 2015, http://www.spaceflight101.com/change-3-mission-updates.html
https://twitter.com/uhf_satcom/status/573237795814301697

Quote
How the instruments fared in the second half of 2014 is unknown, but the core systems of Yutu – its main computer and communications system – kept operating well past the expected duration of three months. Signals from Yutu could be received by radio operators on Earth almost every lunar day as the Chinese mission team kept operating the rover to learn valuable lessons for future robotic missions to the Moon and other targets.
« Last Edit: 06/14/2015 10:51 PM by savuporo »
Orion - the first and only manned not-too-deep-space craft

Offline woods170

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I was surprised to read, catching up to some topics, that Yutu is still alive and talking.

March 9, 2015, http://www.spaceflight101.com/change-3-mission-updates.html
https://twitter.com/uhf_satcom/status/573237795814301697

Quote
How the instruments fared in the second half of 2014 is unknown, but the core systems of Yutu – its main computer and communications system – kept operating well past the expected duration of three months. Signals from Yutu could be received by radio operators on Earth almost every lunar day as the Chinese mission team kept operating the rover to learn valuable lessons for future robotic missions to the Moon and other targets.

Robust little rover.

Offline NovaSilisko

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Robust little rover.

Well, the fact it's just sitting there doing nothing is probably helping its longevity  :P

Chang'e 3 and Yutu are now the longest-lived lunar spacecraft ever by a considerable margin, right?

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