Updates "Hi Artemis, it's been a long time!": China's Chang'e 3 lunar landing mission

[4throck]

I was merely thinking about geometry. Gemini does fit on top of the LEM landing stage ;-)

 

[statickid]

The people who made the set for those pictures obviously copied the set that the Americans and Russians used to make their fake moon photos.

jk :hide::leaving:

 

[Kyle]

The Chang'e 5 proposed mission objects strikes me as a demonstrator for a manned mission with the rendezvous in lunar orbit with the departure stage and the sample return before TEI can take place.

 

[kamaz]

The Chang'e 5 proposed mission objects strikes me as a demonstrator for a manned mission with the rendezvous in lunar orbit with the departure stage and the sample return before TEI can take place.

It would mean that the Chinese have done their homework.

Somewhere in the final reports on the Constellation program there is a comparative analysis of different modes for a Moon mission -- they ended up concluding that the optimal mode is dual-LOR. It's been a while since I have read that (or run the numbers myself), but the basic argument goes like that:

The delta-v between LEO and LLO is about 4km/s, which means that the mass of payload is roughly equal to the mass of EDS(*). So if you have to split the mission in two launches (because you don't have a big enough rocket), there are two options:

EOR+LOR: First launch: Crew+CSM+LEM to LEO. Second launch: EDS to LEO. Rendezvous, transfer to LLO. Rest of mission like Apollo.

Dual-LOR: LEM+EDS, transfer to LLO. Second launch: Crew+CSM+EDS, transfer to LLO. Rendezvous in LLO. Rest of mission like Apollo.

The advantage of the second mode is that logistics is much easier. The LEM can in principle sit in lunar orbit for months (CxP had requirement of 180 days IIRC), so there is no reason to hurry with a second launch: if you have to scrub and wait 14 days for a new TLI window, you scrub and wait. In contrast, in EOR+LOR mode, a problem with the second launch (EDS) means a loss of mission, because the crew in orbit has limited consumables, and cannot wait for 14 days until the new TLI window opens. If you launch EDS first, then EDS also cannot sit in LEO indefinitely, because the propellant (LH2) will boil off.

(*) Interestingly, the same is true for Mars. If you think about it, Mars Direct is actually rendezvous on the surface. The reason why Mars Direct doesn't have rendezvous in Mars orbit is that you can launch everything directly to Mars surface thanks to aerobraking.

 

[garyw]

Do any of the pictures have a date stamp? It'll be fascinating to see how the shadows change with the rotation of the moon.

 

[kamaz]

Paul Spudis on the geology of the landing site: http://blogs.airspacemag.com/moon/2013/12/a-new-site-to-explore-on-the-moon/

Thus, it is reasonable to infer that the mare lavas of the Chang’E 3 site are rich in titanium. In addition, this portion of the Moon is anomalously rich in the radioactive element thorium (Th).

 

[Cosmic Penguin]

Chang'e 3 and Yutu have been spotted by the Lunar Reconnaissance Orbiter on Christmas Day!

In other news both of them are currently in hibernation for the lunar night since Boxing Day. The Sun should rise on around January 10. :zzz:

 

[4throck]

I've posted this rough outline of the mutual photography images at www.unmannedspaceflight.com

For some we only have screencaps. In some cases I've assembled the larger original frames from the various zooms shown in videos.
It's not an artistic composition, but I think it helps in keeping track of things.
Images are grouped by the a, b, c and d stops shown on maps.

Frustrating not to have complete images from the original data, no decent panorama, etc, etc...

 

[4throck]

http://big5.xinhuanet.com/gate/big5/news.xinhuanet.com/photo/2014-01/10/c_125988104.htm

First official panoramas released. Still low resolution copies for the media, but at least they are not photos of TV screens.

 

[Mandella]

Trouble.

http://news.xinhuanet.com/english/china/2014-01/25/c_133073239.htm

 

[Cosmic Penguin]

Trouble.

http://news.xinhuanet.com/english/china/2014-01/25/c_133073239.htm

Unfortunately the reports are too vague to know what exactly the problem is (other than that it is hardware related), but apparently it might just be enough to kill the rover before the "3 month warranty". Well it seems that the rover DID get into sleep mode so let's see what happens in two weeks time.... :uhh:

 

[4throck]

From what I've read, its the camera/antenna mast not folding down.

Speculating a bit, the lack of any images from the second lunar day may indicate that trouble began earlier.
Also interesting is the fact that the rover images were mainly of the lander. Was that due to communication/storage problems?

In all, having the camera and antenna on the same assembly might not be the best design.
But that's how you learn. For a first lander+rover mission, a lot was already achieved!

:hail:

 

[Cosmic Penguin]

From what I've read, its the camera/antenna mast not folding down.

Speculating a bit, the lack of any images from the second lunar day may indicate that trouble began earlier.
Also interesting is the fact that the rover images were mainly of the lander. Was that due to communication/storage problems?

In all, having the camera and antenna on the same assembly might not be the best design.
But that's how you learn. For a first lander+rover mission, a lot was already achieved!

:hail:

An alternative scenario that fits with the description is that one of the solar panels, which is designed to flip into the rover body for thermal protection (the other is left in the open for initial charging at lunar sunrise), refuse to flip back completely. That might cause thermal troubles for the rover, but well these cases are not complete black or white so let's see what happens next (remember that Lunakhod 1 tried not covering its solar panels covers back completely on one lunar night and it survived)...

 

[Cosmic Penguin]

Nothing has been reported since last week.....well you know it's the Chinese and the Sun is still 4 days from rising over the horizon, but..... :shrug:

In the meantime we have this....... :shifty: http://www.thedailyshow.com/watch/tue-february-4-2014/who-froze-jade-rabbit-

 

[Artlav]

http: //www.thedailyshow.com/watch/tue-february-4-2014/who-froze-jade-rabbit-

A-a-ouch.
Some "comedy".

 

[Cosmic Penguin]

Looks like the little rover has survived the lunar night after all! http://www.planetary.org/blogs/emily-lakdawalla/2014/possible-hope-for-yutu.html

 

[MaverickSawyer]

*nervously hails Probe for good luck...*

 

[Cosmic Penguin]

A (long overdue) update: http://www.planetary.org/blogs/guest-blogs/2014/0409-yutu-update.html

 

[boogabooga]

Is it that news is slow to reach English language sources, or is the rover really under secrecy?

 

[Cosmic Penguin]

And another update - despite stuck for months and way beyond its planned lifetime, the rover and its instruments are still working well! (and of course the lander does too, as it should be)

Also it seems that the cause of the rover getting stuck is an electrical short circuit in the bogey control system after colliding with rocks. That's why you build two landers/rovers when landing on the Moon after no one did so in almost 40 years..... :hmm: