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Unmanned _ Chang'e program _ Chang'e 4 farside landing mission

Posted by: A.Nemo Jul 15 2015, 01:35 PM

Preliminary Suggestions for International Cooperation on Chang'E-4 Lunar Probe
Xu Y. (China)

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

Posted by: A.Nemo Jul 15 2015, 01:43 PM

there is a puzzle news:
发布日期:2015年07月14日 字体:【大】【中】【小】

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

Posted by: Juramike Jul 15 2015, 01:49 PM


Posted by: Phil Stooke Jul 15 2015, 03:52 PM

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.


Posted by: Yeh Sep 8 2015, 01:38 PM

Today there's an official confirmation from Xinhua (the state media) that CE4 will be land on the farside: (in Chinese).

Posted by: tolis Sep 9 2015, 01:46 PM

QUOTE (Yeh @ Sep 8 2015, 02:38 PM) *
Today there's an official confirmation from Xinhua (the state media) that CE4 will be land on the farside: (in Chinese).

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

Posted by: Phil Stooke Sep 9 2015, 01:54 PM

It's at L2. More details here:;topic=33402.0;attach=1064984


Posted by: bobik Jan 6 2016, 12:55 PM

QUOTE (A.Nemo @ Jul 15 2015, 02:43 PM) *
there is a puzzle news: ...

This refers probably to the micro-reflector array (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.

Posted by: Thorsten Denk Jan 14 2016, 01:39 PM

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

SinoDefence ‏@SinoDefence
Chang'e 4 mission given goahead.
Relay sat in Jun 18, followed by landing on Moon far side in late 2018.


Posted by: bobik Apr 14 2016, 06:01 PM

German experiment is going to the lunar far side.

Posted by: A.Nemo Apr 15 2016, 08:19 AM

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


Posted by: bobik May 17 2016, 06:45 AM

A installed on the relay satellite and the Swedish instrument for the rover are two other European contributions to the Chang'e-4 expedition.

Posted by: Phil Stooke Jun 3 2016, 02:58 PM

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


Posted by: Phil Stooke Jun 20 2016, 11:14 AM

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.


Posted by: Explorer1 Oct 2 2016, 05:11 PM

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!

Posted by: Phil Stooke Jun 6 2017, 04:15 PM

Chang'E 4 landing site:

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).


Posted by: Phil Stooke Jun 11 2017, 08:24 PM

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


Posted by: antipode Jun 12 2017, 04:37 AM


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


Posted by: Explorer1 Jun 12 2017, 05:35 AM

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.

Posted by: Phil Stooke Jun 12 2017, 05:16 PM

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.


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.

Posted by: Phil Stooke Jul 6 2017, 06:01 PM

More information on site selection for CE4. This image:

from this site:

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.


Posted by: Phil Stooke Jul 7 2017, 12:22 AM

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


Posted by: JRehling Jul 7 2017, 01:32 AM

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.

Posted by: Phil Stooke Jul 7 2017, 06:00 PM

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.


Posted by: Phil Stooke Feb 27 2018, 07:49 PM

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.


Posted by: Phil Stooke Mar 18 2018, 06:09 PM

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.


Posted by: Phil Stooke Apr 11 2018, 05:10 PM

Suggest a name for the CE4 relay satellite:

(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

Posted by: Phil Stooke Apr 22 2018, 06:20 PM

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

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...


Posted by: Phil Stooke Apr 23 2018, 11:48 PM

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)


Posted by: Phil Stooke Apr 24 2018, 02:38 AM,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".


Posted by: Phil Stooke Apr 24 2018, 09:39 PM

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.


Posted by: Phil Stooke May 20 2018, 10:08 PM

The relay satellite was just launched successfully.


Posted by: nprev May 20 2018, 10:23 PM

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

Posted by: Explorer1 May 20 2018, 10:29 PM

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.

Posted by: John Moore May 21 2018, 09:30 AM of launch, or (with different aspect view).

John Moore

Posted by: Phil Stooke May 25 2018, 10:40 PM

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.


Posted by: Phil Stooke May 27 2018, 09:56 PM

Twitter: Jonathan McDowell @planet4589 2 hours ago

So it looks like Longjiang-2 (DSLWP-cool.gif 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.


Posted by: mcmcmc Jun 13 2018, 07:30 AM

"Are we there yet?" wink.gif

Posted by: Phil Stooke Jun 14 2018, 04:16 PM

We are!


Posted by: mcmcmc Jun 14 2018, 05:49 PM

QUOTE (Phil Stooke @ Jun 14 2018, 05:16 PM) *
We are!



Posted by: mcmcmc Jun 14 2018, 06:53 PM

Hayabusa twitter aggregator

Posted by: Thorsten Denk Jun 14 2018, 07:00 PM

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. smile.gif


Posted by: John Moore Jun 14 2018, 07:13 PM are always useful for reference/updates.

John Moore

Posted by: mcmcmc Jun 15 2018, 06:51 AM

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

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