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Unmanned Spaceflight.com > Earth & Moon > Lunar Exploration > Chang'e program
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Thorsten Denk
Interesting speculation by the LROC team about a possible landing place near crater Laplace A:

A Great Place to Rove!

Chang'E/Yutu could land about 10km south east, then (the rover) cross a wrinkle-ridge and reach the rim of the 8km crater.

Thorsten (this is my first name, Denk is the family name)
PaulH51
QUOTE (Thorsten Denk @ Dec 2 2013, 06:01 PM) *
Interesting speculation by the LROC team about a possible landing place near crater Laplace A:
...A Great Place to Rove!...

Welcome Thorsten smile.gif
During the Chinese cntv.cn coverage the commentators disused the landing site : the 'Bay of Rainbows'. Sinus Iridum is Latin for "Bay of Rainbows"
tolis
Looking at the lovely picture of Sinus Iridum a few posts back,
I wonder if the rim of the original crater is supposed to be
somewhere under the lava plain and whether the subsurface radar
of the rover could pick it up.
Phil Stooke
Yes, it would be under the plains, but probably too deep to be detected. I am more interested in a different possibility - there's a bright/dark boundary between two different mare units, best seen in Clementine data (I posted a false color version higher up the thread). If they land near the boundary and drive over it they may be able to detect the underlying unit beneath the overlying one and get the thickness of the top unit. In fact they may get thichnesses of multiple flow units.

Phil

Phil Stooke
This map shows the extent of the landing region, extending quite far outside Sinus Iridum as well as inside it, and the coverage by Chang'E 2 at about 1.5 m/pixel. When we know where the landing will take place I will be adding more maps to zoom in on the site.


PS - for scale, 5 degrees of latitude is 150 km.

Phil

Click to view attachment
Explorer1
Planning a 'Yutu route map' sticky thread Phil? wink.gif
For what it's worth, the LROC team says they'll be photographing the site a few weeks after landing the 25th, January 22nd, and February 18th)
http://lroc.sese.asu.edu/news/index.php?/a...;.html#extended
dvandorn
QUOTE (Explorer1 @ Dec 2 2013, 09:13 PM) *
Planning a 'Yutu route map' sticky thread Phil? wink.gif

You know, that may not be a bad idea. Depending on the volume of images we get from the Chinese, it may be possible to follow the traverse somewhat real-time.

I would imagine we will have to wait to see if we get enough imagery to warrant it, but I'm beginning to think that we may need a dedicated Chang'e/Yutu folder, just as each of the Mars rovers has its own folder and LRO has its own folder, etc.

I am just on pins and needles waiting to see our first new lunar surface vista in decades!

-the other Doug
Phil Stooke
I guess I wasn't subtle enough! Yes, I am planning to map the route - whether in its own thread or not, and that may depend on image access. I am collecting material for a new Moon atlas and this will be part of it.

I will rely very much on our very helpful Chinese contributors for pointing out new articles and other information, translating names of features in the landscape etc.


Phil
RichforMars
This will be interesting. I remember seeing a long while ago the High definition video from the probe that went around the moon years ago. Good Stuff.
dvandorn
With today's imaging technology, I'm hoping for HD video from the lander of the landing itself, and also of Yutu deployment and operations.

-the other Doug
tolis
QUOTE (Phil Stooke @ Dec 2 2013, 09:29 PM) *
Yes, it would be under the plains, but probably too deep to be detected. I am more interested in a different possibility - there's a bright/dark boundary between two different mare units, best seen in Clementine data (I posted a false color version higher up the thread). If they land near the boundary and drive over it they may be able to detect the underlying unit beneath the overlying one and get the thickness of the top unit. In fact they may get thichnesses of multiple flow units.

Phil


So, Chang'e/Yutu will be landing/roving on top of a geologic sandwich.
Cosmic Penguin
Per latest Chinese reports:

Lunar landing is planned at 15:22-15:35 UTC on December 14.

The rover should be deployed from the lander at 20:38-22:21 UTC on the same day. Then some time within the communication window on December 15 at 07:21-15:38 UTC, the lander and rover will photograph each other and sing Moon River together during dating. wink.gif

Source
peter59
At 9:24 pm, it was confirmed that Chang’e-3 had entered the new orbit.
http://www.asianews.co/change-3-probe-move...er-to-the-moon/
It seems that all is well.
Phil Stooke
Yes, only 15 km high at about 45 degrees north. Not long now.


Phil

Phil Stooke
Time for a rather trivial prediction. Unless Chang'E 3 lands at the far eastern end of the mapped landing area, the mountain Promontorium Laplace will be visible on the horizon, barring small-scale local obstructions. That will help to give an idea of the location of the landing site quite quickly.

Phil

charborob
According to my rough calculations, Promontorium Laplace should be visible from about 95km away. If Chang-e 3 lands near the mare ridge S-E of Laplace A, Prom. Laplace would barely be jutting above the horizon.
kenny
QUOTE (Phil Stooke @ Dec 12 2013, 02:43 PM) *
Time for a rather trivial prediction.


Hardly trivial, Phil, given the time you have spent staring at hill tops to determine the uncertain location of Luna 9, in this same quadrant of the moon!

I look forward to seeing the summit of Promontorium Laplace on Saturday...
kenny
This is orbital view of Promontorium Laplace taken by Apollo 15 from the South-South East (looking NNW), over the crater Helicon.

Promontorium Laplace from the SSE

Thorsten Denk
Sunrise in Sinus Iridum!

I'm not an astrophotographer, but I couldn't resist to take some pictures.
(18:54 UTC, downsized to 50% and cropped, original here.)



I was surprised how incredibly fascinating it is to be able
to see with my own eyes (and a 10"-Dobson) the operation area
of a human rover on another celestial body!
Laplace A and the wrinkle ridge were easily visible.

Go, Chang'E! Your landing area is now in sunlight!

Thorsten
Phil Stooke
Very nice!

Joel Raupe, on Lunar Networks reports rumours that the landing site will be in the area shown here.

Phil

Click to view attachment

Cosmic Penguin
Per latest Chinese reports the landing time has shifted to ~13:40 UTC (~8:40 am EST/5:40 am PST/9:40 pm in Beijing).
craigmcg
Thanks Cosmic Penguin. Any update on the time coverage starts?
pospa
QUOTE (craigmcg @ Dec 13 2013, 02:13 PM) *
Thanks Cosmic Penguin. Any update on the time coverage starts?

and / or any published pictures from Moon orbit or the transfer?
charborob
I would be surprised if there were any live coverage, considering how secretive the Chinese are. We'll get an announcement after the landing has occurred, and, I hope, a couple of pictures, but I'm not holding my breath.
Thorsten Denk
Launch had a fantastic two-hours live coverage...
kenny
I really don't think the Chinese are anything like as secretive as they once were. They showed great live coverage of launch and trans-lunar injection on TV.
They have announced in advance a revision of the landing time from 15:35 UTC to 13:40 UTC, so have brought it forward by one orbit.
I think there will be live or near-live coverage on Chinese CNTV. Although there is to be a descent imager snapping away as it lands, that is supposed
to be for planning rover routes, so I doubt if those will be streamed live, and will probably be sent back after the autonomous landing.
SpaceListener
I suppose mostly as Kenny says. Sure Chinese government will announce and show with great detail if the mission was successful and a few words and no images if it fails. Hope that the Saturday would be a great day. smile.gif

The Perilunar orbit of Change'e-3 is of polar orbit from south to north would be above of the Laplace crater at around 43:42 North & 26:56 West? or its perilunar would be at lower latitude such as by 30:00 North in order to take a braking trajectory before landing on Moon?
kenny
Chang’e 3 is now in an intermediate descent orbit of 15 x 100 km, which is of very similar altitude parameters to the descent orbit used by Apollo in the 1960s
and 70s. However, Chang’e is attempting a landing out of a near-polar orbit (90 degrees inclination), which has never been performed before by any spacecraft.

According to Patrick Blau at Spaceflight101, about one hour ahead of the start of the landing sequence (i.e. half an orbit earlier on the far side of the moon),
Chang'e 3 makes an engine burn to further reduce its periselene altitude to just 2 km above Sinus Iridum. This is an extremely low orbit – Apollo regarded a
powered descent start of lower than 16 km as a safety hazard, but I guess we know a lot more about mascons and their orbital perturbations now.

According to Astrogatorsguild web site, it seems the landing is on the southward-travelling portion of the orbit, so it will come in from over the North Pole and start its final
braking over Sinus Iridium. Then it will take 700 seconds from ignition at 2,000 metres altitude down to landing.

Lovely view of the moon this afternoon over Loch Ness, with the terminator already west of Sinus Iridium, and the bay and Promontory Laplace in sunlight,
ready and waiting...
ollopa
Many thanks to Cosmic Penguin and others for the hard information. However, is it just me or is the S/N ratio deteriorating elsewhere on this thread?

A propos Phil's far-from-"trivial prediction": there may be something in the way of that view of Promontorium Laplace.

A fascinating paper (in Chinese, so I'm relying on the pictures) appeared last month in Scientia Sinica: "Geological features and magmatic activities history of Sinus Iridum".

Scientia Sinica

I believe it is fair use to post the LRO/LOLA-based elevation map for the wrinkle ridge near where most people now think Chang'e will land.

Click to view attachment


That will be some view, come tomorrow evening, if................
Astro0
<ADMIN MODE>

From comments in a few recent posts, I just want to remind people to avoid making statements which may imply any political (and I mean that in its broadest sense) commentary about the merits or otherwise of the openness or otherwise of any particular nation's space program, government or media.

As with ANY mission, what data/images are released are a bonus to the public (that includes UMSF'ers) not a right.

</ADMIN MODE>

Just enjoy the ride. smile.gif
PaulH51
Anyone aware of any plans to live stream any of the Chang'e landing process from its mission control center (similar to the launch)
bobik
QUOTE (Cosmic Penguin @ Dec 13 2013, 08:54 PM) *
The best annotated diagram of the lander and rover I have seen so far... rolleyes.gif

The two features labeled as "fuel tanks" are actually "high-pressure gas cylinders" for pressurization of the pressure-fed propulsion system.
Explorer1
Any idea how low Earth will be in the sky to the cameras? Sinus Iridium is even farther from the sub-Earth point than Apollo 17 was, and I know it was lower in the sky from Taurus-Littrow than any of the other landing sites.
Also depends on how high the cameras can be pointed too!
climber
QUOTE (PaulH51 @ Dec 14 2013, 08:02 AM) *
Anyone aware of any plans to live stream any of the Chang'e landing process from its mission control center (similar to the launch)
As usual, think of Emily's blog: http://www.planetary.org/blogs/emily-lakda...g-tomorrow.html
PaulH51
QUOTE (climber @ Dec 14 2013, 03:42 PM) *

Many thanks
kenny
QUOTE (Explorer1 @ Dec 14 2013, 07:05 AM) *
Any idea how low Earth will be in the sky to the cameras?


I estimate around 40 degrees above the horizon, based on the co-ordinates of the intended landing site.
Astro0
Live coverage is up and running on CCTV English edition.

Click to view attachment
nprev
Thanks, Astro0! (Stayed up all night since Ms. Nprev wanted a night on the town. Turns out that she can't drink NEARLY as much as me, so she's beddy-bye. Me, I GOT to see this happen!) wink.gif
Paolo
from the map they showed on CCTV it looks like CE3 is heading to the eastern edge of the landing site, and into Mare Imbrium, close to crater Le Verrier instead of Sinus Iridum
Paolo
stealing borrowing a picture site from NASAspaceflight showing the targeted landing site
Astro0
Chang'e 3 on final descent.

Click to view attachment

Click to view attachment
nprev
Descent apparently proceeding well thus far. (Odd that there are also something like '7 minutes of terror' to do a lunar landing, just like a Mars landing...)
jasedm
Heart in mouth time!

Good luck all!
Hungry4info
Touchdown! A spacecraft is now transmitting data from the surface of the Moon!
Astro0
Touchdown!
Seryddwr
A flawless landing as far as I can see. Well done all!
PaulH51
TD about 2 minutes ago...... smile.gif Image of ground and part of a landing leg....
Paolo
the rabbit has landed wink.gif
in Mare Imbrium instead of Sinus Iridum
nprev
That was SMOOTH, and had frame-by-frame descent imagery as well! Congratulations to the PRC!!!!! smile.gif
Astro0
Images from the descent. Amazing. Too fast to get enough shots to animate.

Here's one frame at about 70 metres (?)

Click to view attachment
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