Preliminary Suggestions for International Cooperation on Chang'E-4 Lunar Probe
Xu Y. (China)
http://www.unoosa.org/pdf/pres/copuos2015/...2015tech08E.pdf

An Introduction of Chang’E-4 Probe:
Probe（Lander,Rover）+ Relay Statellite
Soft-landing on lunar farside
Landing and roving exploration
Will be launched between 2018 and 2019

the probe:
Chang’E-4 probe，lander and rover have the same technical status with the Chang’E -3; but exploration will be redesigned; the payload will be reconfigered; The name of the probe might be changed.
Chang’E-4 probe is a backup spacecraft of Chang’E -3 probe. By now, all platform products of the probe have been manufactured, waiting for further AIT.
The probe will be launched by a long March 3B rocket from the Xichang Statellite Launch Center(XSLC) which is the same way with the Chang'E-3 between 2018 and 2019

The relay statellite:
will be first launched into a lunar transfer orbit about the end of 2018 in the whole mission, then starts its earth-to-moon jurnery alone, and will enter and run in a Halo orbit around the Earth-Moon L2 point; the design life is 3 years.
would provide relay service for the probe and the Earth, and carry out exploration.

Engineering objectives are as follow.
To realize the first soft landing on the lunar farside and perform exploration in human history.
To demonstrate technologies of lunar data relay, landing and roving on complicated terrains of the lunar farside, and lunar night power generation;
To perform further detailed survey on lunar environment in order to lay a foundation for subsequent lunar exploration mission.

Tentative Scientific objectives are as follow.
To study lunar surface dust features and its formation mechanism;
To perform in-situ measurement of lunar surface residual magnetism
and study its interaction with solar wind;
To study lunar surface temperature and particle radiation environment;
To perform lunar surface topology and material composition analysis,
shallow-layer structure survey and study;
To explore and study lunar interior structure of spheres;
To perform lunar based VLF astronomical observation and study

there is a puzzle news:
http://www.cnsa.gov.cn/n1081/n7529/n308608/725881.html
中欧深空探测研讨会在北京召开
发布日期：2015年07月14日 字体：【大】【中】【小】
　　2015年7月9日至10日，中国国家航天局与欧洲空间局在京召开中欧月球探测研讨会，会议围绕嫦娥四号目标任务和有效载荷搭载进行了讨论。
　　会上，欧洲空间局相关专家提出利用嫦娥四号搭载月震仪、快闪相机、激光反射器等载荷的建议。经商议，双方初步确定将月震仪和快闪相机等四个有效载荷纳入合作范围。欧洲空间局负责协商欧洲载荷以及其总成与接口，中方通过双边航天局长会晤推动建立载荷研制国技术团队，争取在2018年提交正样。
　　来自法国巴黎索邦大学、瑞士苏黎世理工、澳门科技大学以及中国国家航天局探月与航天工程中心、中国科学院、北京大学、中国科学技术大学、中国地质大学等单位的专家学者参加了会议。

laser reflector, it means Chang'e 4 will be landed on nearside, What will happened?

(Edited!)

The current Chinese plan is to land on the far side. The laser reflector is suggested as a high priority payload by an ESA group looking at cooperation. The two don't work together, so we don't know which way it will go. But it's not a contradictory plan, it's an external suggestion to change the plan. Probably won't happen, because the prestige (and science value) of the first far side landing is likely to trump that one payload suggestion.

Incidentally, there's really no reason why that laser reflector shouldn't be mounted on the landing stage of the Chang'E 5 sample return lander, which will be near side. That's a far more likely outcome than flying it on CE4.

Phil

Today there's an official confirmation from Xinhua (the state media) that CE4 will be land on the farside: http://news.xinhuanet.com/tech/2015-09/08/c_1116498505.htm (in Chinese).

In that case, they will need a relay satellite, either in lunar orbit or further afield eg Earth-Moon L2

It's at L2. More details here:

http://forum.nasaspaceflight.com/index.php...;attach=1064984

Phil

This refers probably to the micro-reflector array INRRI (Instrument for landing-Roving laser Retroreflectors Investigations). INRRI has been sized to give the right signal for LOLA (Lunar Orbiter Laser Altimeter) on LRO. By the way, one INRRI was mounted on EDM Schiaparelli as long-time scientific asset.

It seems that Cháng'é 4 will go to the lunar farside end of 2018!


https://twitter.com/SinoDefence/status/687618528933998592
http://www.chinadaily.com.cn/micro-reading...t_14484287.html

Thorsten

German "Lunar Lander Neutron Dosimetry" (LND) experiment is going to the lunar far side.

China Follow-on Luna Exploration Projects:
2018,Chang'e-4 to farside of Moon
2023,Chang'e-6(?) ,sample&return from farside of Moon
2025,Chang'e-?, south pole landing & large area cruise
2027,Chang'e-?, north pole landing & ISRU Experimental

A joint Dutch and Chinese low frequency receiver installed on the relay satellite and the Swedish Advanced Small Analyzer for Neutrals (ASAN) instrument for the rover are two other European contributions to the Chang'e-4 expedition.

http://www.chinaspaceflight.com/satellite/.../CE-4/CE-4.html

Chang E IV: June 2018 Long March rocket four C relay communications satellite in late 2018 Long March III B rocket lander and inspection devices.

This item includes an image of the general landing area in the Apollo basin. Long Xiao had suggested to me at LPSC that this would be the (or a) target

http://www.chinaspaceflight.com/usr/upload...41417135287.jpg

Phil

A fascinating new paper is now online - Wang and Liu (2016), A Chang’e-4 mission concept and vision of future Chinese lunar exploration activities, Acta Astronautica (available online 11 JUne 2016). If you have access!

It suggests that Apollo basin is the most likely target but other farside basins are possible. Also looks ahead to future missions, including a suggestion that a robotic station could be built up, possibly as a precursor to human flights. From 3 to 5 landers near the south pole, carrying between them up to a dozen rovers, to build the station, which has obvious echoes of ESA's robotic lunar village.

Phil

http://spaceflightnow.com/2016/09/29/china...de-of-the-moon/

Near side sample return might be launched next year, while the far side relay could be used by other space agencies for their own missions. It would certainly save good money!

Chang'E 4 landing site:



https://www.chinaspaceflight.com/satellite/.../CE-4/CE-4.html


Landing area - 45.5 degrees south latitude, 178 degrees east longitude

This is on the flat floor of the large crater Von Karman, with a bit of ejecta from the relatively young crater Finsen. Until now most indications had been for a landing near the Apollo basin at about 42 south, 157 west (203 east).


Phil

Here's a couple of maps showing the CE4 area.

Phil

Click to view attachment

Phil

I take it Von Karman's walls are sufficiently lofty to be visible in any surface imagery taken from inside that box?

p

I wouldn't be so sure; the horizon is really close in the Chang'E 3 surface images. We shouldn't expect huge vistas anymore than we get them on Mars; cool terrain is by definition hazardous!
I would welcome being pleasant surprised to see anything more than a few km away, of course.

Short answer - I think some relief will be visible. Von Karman is about 3500 m deep and some distant topography should show up.

I will post something on the Chang'E 3 thread about distant topography. There are distant hills to the north and west at distances of 10 to 15 km, protruding above closer topography. To the east the horizon is about 4 km from the lander.

Phil

EDIT: OK, I posted in the other thread. That was a very flat site, but local high spots can be seen about 10 km away. I would expect that either the central peak of Von Karman or the SE wall of the crater should be visible from the lander, and possibly both will be, as well as small crater rims closer to the landing site. Not high mountains like Taurus-Littrow, but distant features should be visible, appearing as low hills.

More information on site selection for CE4. This image:

https://www.chinaspaceflight.com/usr/upload...53834140857.jpg

from this site:

https://www.chinaspaceflight.com/satellite/.../CE-4/CE-4.html

shows a number of sites at about 45 degrees north or south. I am preparing something on this topic, so I will post a map later. Some sites are in mare-type areas of the SPA basin or the large craters in that area, but the northern sites are all in or between large craters in the highlands (Mare Moscoviense is not one of these areas).

This is from a presentation at the German Aerospace Centre DLR, where China and Germany have just agreed to cooperate on the mission, Germany joining several other countries.

Phil

Here is a map of those sites from the slide linked to above.

Phil

Click to view attachment

Probably everyone knows this, but on the Moon, the horizon is inherently closer than from a similar vantage point on Earth or Mars. Though the bowl of a crater may make the global curvature locally moot.

That's true, of course, but the distance to the ideal horizon is not as important as the height and distance of significant relief features. Von Karman is about 160 km across and up to 4 km deep (wall height varies quite a bit). A good comparison might be with Flamsteed P, the flooded crater which Surveyor 1 landed in. It is 80 km across, but mostly filled with lava and with hills 1500 m high protruding above the plains. Hills 20 km away were visible in the Surveyor 1 panorama. Scaling up, I am confident there will be some relief on the CE4 horizon. Maybe if the landing is in exactly the worst place for viewing relief there would not be much, but from many areas some features will be visible.

Phil

The Von Karman site may not be the final word on site selection... it was identified in a paper in 2017, but two papers by Jia et al. in 2018 (one in the Chinese Journal for Deep Space Exploration, the other in Planetary and Space Science, essentially the same content) prefer the site numbered S5 in the map a few posts above. It is south of the Apollo basin and closer to the centre of the SPA basin than any other of those mapped sites. I think all we have right now is competing suggestions, and the final target may still be uncertain.

Phil

I'm at the Microsymposium just prior to LPSC. It just concluded, with presentations on the Chang'E program and others. Specifically for this thread, Von Karman seemed to be the likely site again - Apollo was promoted as a good site but probably for a future mission.

Phil

Suggest a name for the CE4 relay satellite:

http://www.nssc.cas.cn/tzgg2015/tzgg_tzgg/...29_4987980.html

(Google translation)

Concerning the notification of the recruitment of the No. 4 relay star name
Article Source: Release Time:2018-03-29
All relevant units:

　　The fourth relay satellite will be launched in May 2018. Considering that the No. 4 mission will be the biggest bright spot in China's aerospace field in 2018, to further establish a good image of the lunar exploration project and expand the influence of the project, the Lunar Exploration and Space Engineering Center plans to use the project implementation unit as the main target for solicitation of No. 4 Relay star name.

　　The No. 4 relay star name collection activity will take place from March 27 to April 15, 2018. The names so collected should reflect the theme of lunar exploration, have innovative and significant technological and cultural characteristics, be positive, and conform to the socialist core values.

　　Specially invited your organization to participate in this solicitation. Please refer to the attachment for specific requirements.

　　Attachment: Program for Selection of Relay No. 4 Relay Stars

　　Moon Exploration and Aerospace Engineering Center

　　March 27, 2018

This link is to the current issue of China's Journal of Deep Space Exploration:

http://jdse.bit.edu.cn/sktcxben/ch/reader/issue_list.aspx

A very interesting set of papers about the CE4 landing site including several suggestions for landing sites and even rover traverse routes. Chinese language with English abstract, but Google document translation will help, and the illustrations carry a lot of information even without translation. Many of these papers will probably appear in English elsewhere at a later date. I can feel a map coming on...

Phil

After a suitable gestation period, here is a map of the sites suggested for Chang'E 4 in Von Karman crater. The references are from the previous post except the mention of Snape et al. (2010) which is an LPSC abstract, easy to search for if you need it. THe bottom map includes possible traverses suggested by Mou et al. (2018)

Phil

Click to view attachment

http://news.cnstock.com/news,bwkx-201804-4214240.htm

Google translate:

China Securities News reported on April 24 from the National Bureau of Science, Technology, and Technology that during the opening ceremony of the "China Aerospace Day" home event in 2018, Wu Yanhua said that the Chang'e 4 is one of the major tasks for China's space industry this year...

Wu Yanhua announced at the opening ceremony that the No. 4 relay star was named "Bianqiao" and the two small satellites were named "Longjiang No. 1" and "Longjiang No. 2".

Phil

Interesting that Google translates that website to give the relay satellite name 'Bianqiao', but all other sources - AND using Google to translate just the characters for that name, give 'Queqiao'. The names mean Magpie Bridge (relay) and Dragon River (the two small satellites), and there are numerous tweets and stories out there today giving the background.

Late in the year we will presumably get a name for the new rover.

Phil

The relay satellite was just launched successfully.

Phil

Ah, thanks, Phil! Was wondering; didn't seem to be a live feed available anywhere.

Someone at the site pointed their phone at a screen, and streamed it out via a Chinese media platform; looks like the micro-satellites also separated successfully.

Video 1 of launch, or Video 2 (with different aspect view).

John Moore

It seems all is well with our new mission - the relay satellite has passed the Moon and is on its way to its L2 halo orbit. The two little moon orbiters are in lunar orbit. Hoping for an image or two from the Saudi camera on one of them.

Phil

Twitter: Jonathan McDowell @planet4589 2 hours ago

So it looks like Longjiang-2 (DSLWP- is in a 350 x 13800 km x 21 deg lunar orbit. Longjiang-1 seems to have failed on May 21 and presumably remains in distant Earth orbit following its lunar flyby
------------------


I spoke prematurely in my last post - all seems well with the other two spacecraft but Longjiang 1 failed. The small camera is on Longjiang 2. I see some reports that radio enthusiasts will be able to download images from the camera, but I don't know the details yet.

Phil

"Are we there yet?"

We are!

http://spacenews.com/change-4-relay-satell...in-lunar-orbit/

Phil

Cool!

Hayabusa twitter aggregator
http://win98.altervista.org/hayabusa2/TwitterAggregator.html

Nice pic, but it's not new.
It's from Chang'e-5 T1, from october 2014.

This one is new, from the Longjiang-2 micro satellite.
The camera has captured its place of origin, Saudi Arabia.

Thorsten

Andrew Jones's observations are always useful for reference/updates.

John Moore

Better images from Saudi Arabia camera onboard Longjiang-2 satellite, the only survivor of the two small satellites launched together with Queqiao:




http://www.planetary.org/blogs/jason-davis...earth-pics.html

Andrew Jones (https://twitter.com/AJ_FI) reports some new images from the Saudi camera. EDIT - Andrew has just pointed out to me that the image is not from the Saudi camera, but from a second camera which I was not aware of or had forgotten about. This was developed by students in China.

One, which I assume is a mosaic of many image strips, covers Mare Nubium. This shows the image coverage on a background from LRO Quickmap.

Phil

Click to view attachment

I think those are just symptoms of SSTV ham radio downlink.

Yes, looking at it now I'm inclined to agree.

Phil

http://www.spaceflightfans.cn/39192.html#more-39192


Summarizing from the above link, using Google translation:


The Chang'e 4 rover will have a name soon. A competition was held starting on 15 August, and on 18 September a shortlist of the many submitted names was announced after a meeting in Beijing.


The shortlisted names are:

dream-by-dream
Guangming [= bright or brightness]
Yutu No.2
exploration
journey
elf
fearless
Wangshu (one of the former kingdoms of China 1000 years ago)
walker
golden rabbit


(the first one looks like a bad translation)

The final name will be picked in October.


Phil

Golden rabbit sounds really fun! It has my vote (for what it's worth...)

Click to view attachment

Phil