LIVE: Chang'e-3 lunar probe and rover, CZ-3B - Xichang - December 1, 2013

[cmj9808]

Do we have a ground track for this launch?  I'm interested because the rover has a Plutonium 238 radioisotope thermoelectric generator.

The rover is solar powered. But it has RHUs.

Hmmmm.  AIAA got it wrong then (RTG was listed in an Aerospace America article).  RHU's still make me interested in the ground track.

 - Ed Kyle

AIAA is right. It's a BiTe thermoelectric converter-based small RTG whose output is about 0.1We, similar to the Angel RTG used on Mars 96 lander. The RTG can only drive electric heaters during the lengthy night because of such a low power, so basically, it's used as a RHU.

[Blackstar]

AIAA is right. It's a BiTe thermoelectric converter-based small RTG whose output is about 0.1We, similar to the Angel RTG used on Mars 96 lander. The RTG can only drive electric heaters during the lengthy night because of such a low power, so basically, it's used as a RHU.

But the paper that was attached earlier states:

"During the lunar nights, the Lander and the Rover will go into the lunar-night sleep mode, and by use of radioisotope heater units (RHU) and two-phase fluid loops, lunar-night survival will be achieved."

Do they use a fluid system for the lander and an RTG for the rover?

[cmj9808]

AIAA is right. It's a BiTe thermoelectric converter-based small RTG whose output is about 0.1We, similar to the Angel RTG used on Mars 96 lander. The RTG can only drive electric heaters during the lengthy night because of such a low power, so basically, it's used as a RHU.

But the paper that was attached earlier states:

"During the lunar nights, the Lander and the Rover will go into the lunar-night sleep mode, and by use of radioisotope heater units (RHU) and two-phase fluid loops, lunar-night survival will be achieved."

Do they use a fluid system for the lander and an RTG for the rover?

I just read the paper <Technological advancements and promotionroles of Chang’e-3 lunar probe mission>. So based on the described information, it seems the engineering team chose RHU rather than RTG for both rover and lander.
The RTG was mentioned by Dr. Ouyang Ziyuan, PI of the Chang'e lunar explore program. Given that Dr. Ouyang is an astronomer, it's possible that he confused RTG and RHU. 

[Blackstar]

Does anybody mention what isotope they are using? is it Pu-238?

If so, that has interesting implications, because China did not (and may still hot) have the capability to manufacture Pu-238.

[plutogno]

Does anybody mention what isotope they are using? is it Pu-238?

Xinhua is reporting Pu-238
http://news.xinhuanet.com/english/sci/2013-11/02/c_132853309.htm

[Blackstar]

Does anybody mention what isotope they are using? is it Pu-238?

Xinhua is reporting Pu-238
http://news.xinhuanet.com/english/sci/2013-11/02/c_132853309.htm

That article also says that the nuclear battery "will power" the rover. I think that's wrong. The rover has solar panels.

[elakdawalla]

A member of 9ifly forum has made a 3-D animation of Chang'e-3 mission and loaded it on youtube. IMO, it's really nice work. He would very much appreciate it if you guys can give some comments and suggestions.

This video is now private -- does anyone have any information on why? Is there another version somewhere? There is no other version on the user's Youtube channel.

[Warren Platts]

Dr. Spudis has a new blog article Chang'e-3 lander:

http://www.spudislunarresources.com/blog/china-america-and-the-moon-boldness-and-abdication/#comment-1800

Wu Ji, director general of the China National Space Science Center, reportedly is “dismayed by recent changes.... I feel that America is gradually contracting and closing itself off.  It’s a very strange thing.” ...

No doubt we will continue to misread Chinese intentions in space, as we have done so many times for so many other areas of policy over the years.  If space has national geopolitical implications (and the past 50 years of history demonstrates that it does), our absence from the Moon is as just significant as Chinese interest in (and use of) it.

[Blackstar]

Conversed with one of my colleagues who is very familiar with the isotopes stuff. He said that he's done a lot of research on Chinese capabilities and has determined that the material on the lander and rover is:

-Pu-238
-in RHU form (NOT RTGs, unlike what has been reported in several places)
-manufactured in China.

On that last point, he said that the Chinese have invested in the expensive infrastructure required to manufacture the Pu-238. That could have some interesting implications. Does it imply that they have more ambitious robotic spacecraft missions in mind?

I'm writing something for TSR on this subject.

[Star One]

Conversed with one of my colleagues who is very familiar with the isotopes stuff. He said that he's done a lot of research on Chinese capabilities and has determined that the material on the lander and rover is:

-Pu-238
-in RHU form (NOT RTGs, unlike what has been reported in several places)
-manufactured in China.

On that last point, he said that the Chinese have invested in the expensive infrastructure required to manufacture the Pu-238. That could have some interesting implications. Does it imply that they have more ambitious robotic spacecraft missions in mind?

I'm writing something for TSR on this subject.

Well as they appear to have the intent to send a craft to Jupiter surely such a capability is a must for such a mission. Best I would have thought to get the experience in now before carrying out something so ambitious.

[savuporo]

No launch date yet? Need to plan a launch party.

Actually, after scanning recent articles i found this :
http://eandt.theiet.org/magazine/2013/10/news-analysis.cfm

China is often criticised for not being specific about mission dates, but this is probably because the nation’s space programme is led more by engineering conservatism than media-savvy politicking. The Western alternative of announcing dates, and then delays or cancellations, is no better. That said, Xu Dazhe, the chairman of China Aerospace Science and Technology Corp, gave the launch date of Chang’e 3 as 13 December, arguably another example of increasing transparency

[Galactic Penguin SST]

No launch date yet? Need to plan a launch party.

Actually, after scanning recent articles i found this :
http://eandt.theiet.org/magazine/2013/10/news-analysis.cfm

China is often criticised for not being specific about mission dates, but this is probably because the nation’s space programme is led more by engineering conservatism than media-savvy politicking. The Western alternative of announcing dates, and then delays or cancellations, is no better. That said, Xu Dazhe, the chairman of China Aerospace Science and Technology Corp, gave the launch date of Chang’e 3 as 13 December, arguably another example of increasing transparency

Hmm... all Chinese and English sources that I have seen indicates . December 1 GMT launch date - but can he be reporting the time of D-day?

[savuporo]

The 1st December date was mentioned back in August, i haven't found a more recent cite
http://www.planetary.org/blogs/emily-lakdawalla/2013/08280858-change-3-proceeding-toward-launch.html

Considering Akin's laws of spacecraft design:

27. (Varsi's Law) Schedules only move in one direction.

Either a slip, or, a miscommunication and the 13th date could be indeed the d-day.

[Blackstar]

A few weeks ago I was at a Lunar Exploration and Analysis Group (LEAG) meeting where somebody was presenting all the information he had gathered about Chang'e-3. I was not listening closely, but I believe he had some information about the tracking ship schedule and it did not completely jibe with a December launch. Something like the tracking ship returning to port by the beginning of December. Probably just faulty data, but perhaps worth looking at.

[Galactic Penguin SST]

A few weeks ago I was at a Lunar Exploration and Analysis Group (LEAG) meeting where somebody was presenting all the information he had gathered about Chang'e-3. I was not listening closely, but I believe he had some information about the tracking ship schedule and it did not completely jibe with a December launch. Something like the tracking ship returning to port by the beginning of December. Probably just faulty data, but perhaps worth looking at.

Quite the opposite - according to latest AIS tracking all the tracking ships are currently at port and will go out very soon. 

[Blackstar]

A few weeks ago I was at a Lunar Exploration and Analysis Group (LEAG) meeting where somebody was presenting all the information he had gathered about Chang'e-3. I was not listening closely, but I believe he had some information about the tracking ship schedule and it did not completely jibe with a December launch. Something like the tracking ship returning to port by the beginning of December. Probably just faulty data, but perhaps worth looking at.

Quite the opposite - according to latest AIS tracking all the tracking ships are currently at port and will go out very soon. 

He had found something like a future schedule that showed one or more of them returning to port in December. I was not paying enough attention to find out what his source was. He said that most sources indicated a December launch, but he had this one piece of data that did not fit.

[Blackstar]

I have read the Aerospace America article by Craig Covault on CE-3 and I was underwhelmed by it. I don't know why the author did not contact any American robotic spacecraft experts (JPL and MSFC have studied robotic lunar landers in detail, and Ames has also looked at the subject). Aldrin and Cernan are really not good sources for an article about robotic exploration of the Moon. That said, the article made an interesting claim that the Chinese are building SIX of these landers:

-CE-3 and a backup
-CE-4 and a backup
-CE-5 and a backup

He claims that CE-4 and 5 are both sample return missions.

Does anybody have a reliable source for this information?

[savuporo]

He claims that CE-4 and 5 are both sample return missions.

Does anybody have a reliable source for this information?

The numbers seem off, all previous articles said that Chang'e 4 is a backup built for Chang'e3, just as Chang'e-2 was a backup craft built for Chang'e 1, with its mission expanded after inital success. Chang'e-4 launch date has been quoted as 2014-2015 in the past.
Multiple articles say the same, but this one has the quote from the source
http://english.sina.com/technology/2012/0724/489448.html

According to Ouyang, the Chang’e-4 satellite will be the back-up of Chang’e-3, thus leaving the task to Chang’e-5 to return to Earth carrying with samples from the moon.
Because the Chang’e-5 will be too heavy for the current carrier rockets, China plans to launch it in Wenchang, Hainan province with the Long March- 5 rocket which is still under development.

EDIT: I dug up a series of articles from Xinhuanet english, making a mention of either Chang'e 4 or 5. They have recently talked more about 5, rather than 4. Here are relevant quotes with the speaker name included


http://news.xinhuanet.com/english2010/china/2011-03/02/c_13758065.htm
2011-03-02

China is expected to launch its fifth lunar probe, Chang'e-5, in 2017 to send back a moon rock sample to earth, a top Chinese space scientist told Xinhua Wednesday.

A lunar landing probe, lunar surface patrol device and other equipment would be carried by Chang'e-5, said Ye Peijian, chief designer of Chang'e-1, the country's first moon probe, and chief commander of the Chang'e-2 and Chang'e-3 missions.
...
"A soft-landing on moon will be a main aim for Chang'e-3," Ye said.
...
After Chang'e-3, China would launch Chang'e-4 with the goal of achieving automatic patrols on the moon, Ye said.

http://news.xinhuanet.com/english/china/2012-03/05/c_131447340.htm
2012-03-05

The launch of Chang'e-3 and Chang'e-4 is part of the second step of China's three-phrase lunar probe projects of orbiting, landing and returning.

http://news.xinhuanet.com/english/china/2013-03/14/c_132232333.htm
2013-03-14

Chang'e-5 is expected to be China's first lunar explorer to return to Earth. The mission will be carried out before 2020.

The experimental spacecraft will consist of the Chang'e-2 lunar orbiter base structure as well as the return capsule that will be used by the Chang'e-5, said Hu Hao, chief designer of the lunar exploration program's third phase and a deputy to the National People's Congress.

"The Chang'e-5 mission will enter the prototype phase this year," he said. The mission involves a "relay" approach that requires precision rendezvous and docking in lunar orbit

http://news.xinhuanet.com/english/sci/2013-11/02/c_132853309.htm
2013-11-02

..according to Ouyang Ziyuan, the project’s chief scientist.
The country will launch its fifth lunar probe, the Chang’e-5, in 2017 to bring back samples from the surface of the moon in the final step of the its unmanned lunar project, Ouyang said.

This 2011 presentation also explicitly says:
http://www.oosa.unvienna.org/pdf/pres/stsc2011/tech-49.pdf

Chang’e-4 Mission
Chang’e-4 Mission Chang’e-4 is the backup of Chang’e-3 mission

Plus this : http://www.johnslewis.com/2013/02/exploring-moon-next-ten-years.html

In 2015 we can expect the launch of China’s Chang’e 4 lander and rover.  This mission, featuring increased rover autonomy, will extend the technical scope of Chang’e 3

So all sources seem to indicate that 4 will be the same platform as 3, taking some more risks and extending the autonomy.

[Blackstar]

Thanks for that. But aside from the numbers, is there any indication that they are mass producing the spacecraft? Do they have five more building in addition to Chang'e-3?

[Blackstar]

My further pursuit of information on the Chang'e-3 RHUs: