IPB

Welcome Guest ( Log In | Register )

31 Pages V  « < 9 10 11 12 13 > »   
Reply to this topicStart new topic
Chang'e-4 farside landing mission
HSchirmer
post Jan 11 2019, 10:05 PM
Post #151


Member
***

Group: Members
Posts: 684
Joined: 24-July 15
Member No.: 7619



QUOTE (stevesliva @ Jan 11 2019, 06:48 PM) *
Amazing how fractal the cratering is. Well, amazing when I realize I have no idea of vertical height when looking straight down.

I've heard from family who flew over the Atlantic, Pacific and Gulf of Mexico that ocean waves are fractal.
You can't tell vertical height by looking down, waves at 10-feet up look just like waves at 100-feet up, which look just like waves at 1,000-feet up. That's why, when you're on a parachute, you don't look down; you look at the horizon to judge altitude, and you don't release the parachute harness until your feet hit the water.

- Interesting whether the fractal dimensions of cratering might constrain the atmospheric properties of moons and planets?

Curious- are there any papers on "fractal dimensions of lunar craters" addressing the range of sizes?
Go to the top of the page
 
+Quote Post
neo56
post Jan 11 2019, 10:07 PM
Post #152


Member
***

Group: Members
Posts: 808
Joined: 3-June 04
From: Brittany, France
Member No.: 79



Thanks Phil. The resolution of images on the quickmap was enough to locate the landing site.
Here is a montage I did to help locate it.



And my guess on the orientation of Chang'E 4 based on the shadows and position of craters:
Attached Image


--------------------
Go to the top of the page
 
+Quote Post
wildespace
post Jan 11 2019, 11:36 PM
Post #153


Member
***

Group: Members
Posts: 238
Joined: 15-January 13
Member No.: 6842



QUOTE (neo56 @ Jan 11 2019, 08:42 PM) *
Phil, where did you download this picture? I'm on the QuickMap LROC website but the resolution is not as good as your picture.

For everybody's convenience, here's a high-quality NAC strip of the area:

http://wms.lroc.asu.edu/lroc/view_lroc/LRO....0/M134022629LE

The landing site is slightly below the centre of the image strip.

200% scale crop:

Attached Image


--------------------
Go to the top of the page
 
+Quote Post
Phil Stooke
post Jan 12 2019, 06:25 PM
Post #154


Solar System Cartographer
****

Group: Members
Posts: 10128
Joined: 5-April 05
From: Canada
Member No.: 227



I know several of us were looking for the landing location in images like these before we saw the panorama. I looked at this place among many others, but I thought the hazard avoidance system would divert the lander away from a place like that which is surrounded by craters. There are nice smooth spots close by, to the west or northeast. But it's all about the scale of the hazard avoidance, I suppose. We did get a nice level area between the craters.

Phil


--------------------
... because the Solar System ain't gonna map itself.

Also to be found posting similar content on https://mastodon.social/@PhilStooke
NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain)
Go to the top of the page
 
+Quote Post
Phil Stooke
post Jan 12 2019, 10:23 PM
Post #155


Solar System Cartographer
****

Group: Members
Posts: 10128
Joined: 5-April 05
From: Canada
Member No.: 227



While waiting for news of any activity on the 12th, here is a comparison of horizon features between the panorama and an LRO wide angle (heavily processed) image.

The central peak is visible, but Ba Jie crater is not. More than half of the horizon is the rim of Von Karman. The small hill about 10 km north of the lander, which might make a good target for the traverse, is probably visible as a low ridge labelled X here.

Phil

Attached Image


EDIT: My crater 'C' might be the one higher up on the rim of the main crater, with ridge D adjacent to it.


--------------------
... because the Solar System ain't gonna map itself.

Also to be found posting similar content on https://mastodon.social/@PhilStooke
NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain)
Go to the top of the page
 
+Quote Post
wildespace
post Jan 13 2019, 08:19 AM
Post #156


Member
***

Group: Members
Posts: 238
Joined: 15-January 13
Member No.: 6842



QUOTE (Phil Stooke @ Jan 12 2019, 06:25 PM) *
I know several of us were looking for the landing location in images like these before we saw the panorama. I looked at this place among many others, but I thought the hazard avoidance system would divert the lander away from a place like that which is surrounded by craters. There are nice smooth spots close by, to the west or northeast. But it's all about the scale of the hazard avoidance, I suppose. We did get a nice level area between the craters.

Phil

The landing footage shows the craft pausing briefly when over that location, seemingly detecting an even space between those craters, and "making the decision" to land there. Simple and effective, just like what Chinese would do.

https://www.youtube.com/watch?v=JJi_YEubKCY&t=1m54s


--------------------
Go to the top of the page
 
+Quote Post
wildespace
post Jan 13 2019, 08:46 AM
Post #157


Member
***

Group: Members
Posts: 238
Joined: 15-January 13
Member No.: 6842



"The space probe is moving south across the Mün"

Excellent video processing and analysis here. https://www.youtube.com/watch?v=unEbg_dt3DM


--------------------
Go to the top of the page
 
+Quote Post
Huguet
post Jan 13 2019, 02:02 PM
Post #158


Member
***

Group: Members
Posts: 185
Joined: 4-January 19
Member No.: 8523



Panoramas from chang'e-3 and chang'e-4. I expected the number and pattern of the impact craters to be more diferent beetween the two landing sites, it apears to have double of small craters (less than 1 meter) on the darkside.
Attached thumbnail(s)
Attached Image
 


--------------------
"The Earth is a very small stage in a vast cosmic arena"
Go to the top of the page
 
+Quote Post
Thorsten Denk
post Jan 13 2019, 02:19 PM
Post #159


Member
***

Group: Members
Posts: 122
Joined: 3-September 12
From: Almeria, SE Spain
Member No.: 6632



I think we have to be careful with generalizing
"lunar farside" = "heavily cratered" = "this landing spot".

The first "=" is generally true,
but the specific Cháng'é-4 landing site
is a lava flooded crater and hence
should rather have properties of (near side) Mare areas.
Untypical for far side in general.

The difference in craters should be more indicative
to age than to "near" vs "far" side.

Thorsten
Go to the top of the page
 
+Quote Post
Steve G
post Jan 13 2019, 08:03 PM
Post #160


Member
***

Group: Members
Posts: 289
Joined: 29-December 05
From: Ottawa, ON
Member No.: 624



Chang'e 3 landed on lunar maria, Chang'e 4 on lunar highlands, which is a big difference especially in age, so I'd expect more craters in a highland area. Of course, that depends on the age of the basin in Von Karman.
Go to the top of the page
 
+Quote Post
Phil Stooke
post Jan 14 2019, 05:51 AM
Post #161


Solar System Cartographer
****

Group: Members
Posts: 10128
Joined: 5-April 05
From: Canada
Member No.: 227



Von Karman is filled with basalt lava flows, probably not very different in age than typical mare basalts on the Earth-facing side of the Moon. Von Karman is in the highlands but its floor is not highland, in other words. But these things are deceptive. Because highland surfaces are older they have a thicker regolith, and it affects the survival of small craters during impact-generated siesmic shaking. Sometimes highland surfaces can look smoother and younger just because their craters are more softened by shaking. A slope helps that process, so the rolling topography of highland areas is ideal for erasing craters in this way.

Here is an example from Flamsteed, the almost completely buried crater in which Surveyor 1 landed in 1966. Mare basalt at the top, low relief highland surface at the bottom. The image is about 800 m wide, 1.9 south, 43.0 west. More craters in a given area on the mare, but the highlands are older. At this scale they just don't preserve craters. Larger craters are not erased this way so at broad scales the basic rule 'older = more craters' is true.

Phil

Attached Image


--------------------
... because the Solar System ain't gonna map itself.

Also to be found posting similar content on https://mastodon.social/@PhilStooke
NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain)
Go to the top of the page
 
+Quote Post
kenny
post Jan 14 2019, 07:30 PM
Post #162


Member
***

Group: Members
Posts: 547
Joined: 1-May 06
From: Scotland (Ecosse, Escocia)
Member No.: 759



Lovely little color video of Yutu-2 driving away from the Chang'e-4 lander and executing the 180 degree turn ...

Yutu-2 driving away from lander
Go to the top of the page
 
+Quote Post
Hungry4info
post Jan 15 2019, 06:42 AM
Post #163


Senior Member
****

Group: Members
Posts: 1414
Joined: 26-July 08
Member No.: 4270



China's Chang'e-4 probe conducts first bio test on moon as first plant grows
https://news.cgtn.com/news/3d3d414f7949444d...54/share_p.html

Edit: From this Global Times article.
QUOTE
Chinese media state that the experiment contains six species: cotton, rapeseed, potato, arabidopsis, fruit fly and yeast, with Xinhua reporting that no signs of growth have been found among the species other than cotton.

Attached thumbnail(s)
Attached Image
Attached Image
 


--------------------
-- Hungry4info (Sirius_Alpha)
Go to the top of the page
 
+Quote Post
GoneToPlaid
post Jan 15 2019, 09:03 AM
Post #164


Junior Member
**

Group: Members
Posts: 31
Joined: 24-February 17
From: California
Member No.: 8127



[quote name='Phil Stooke' post='243419' date='Jan 13 2019, 09:51 PM']Von Karman is filled with basalt lava flows, probably not very different in age than typical mare basalts on the Earth-facing side of the Moon. Von Karman is in the highlands but its floor is not highland, in other words...

Phil

Very true. In fact, where Chang'e-4 landed is approximately -6km relative to the moon's mean radius. Definitely not highlands, and instead is lowlands within the huge Von Karman crater floor.
Go to the top of the page
 
+Quote Post
Phil Stooke
post Jan 15 2019, 06:41 PM
Post #165


Solar System Cartographer
****

Group: Members
Posts: 10128
Joined: 5-April 05
From: Canada
Member No.: 227



I have been following the discussion here:

http://www.9ifly.cn/thread-5819-70-1.html

(in translation) which seems to be saying that a power failure has ended the biological experiment. Does anyone have any other information?

Phil


--------------------
... because the Solar System ain't gonna map itself.

Also to be found posting similar content on https://mastodon.social/@PhilStooke
NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain)
Go to the top of the page
 
+Quote Post

31 Pages V  « < 9 10 11 12 13 > » 
Reply to this topicStart new topic

 



RSS Lo-Fi Version Time is now: 30th March 2024 - 05:00 AM
RULES AND GUIDELINES
Please read the Forum Rules and Guidelines before posting.

IMAGE COPYRIGHT
Images posted on UnmannedSpaceflight.com may be copyrighted. Do not reproduce without permission. Read here for further information on space images and copyright.

OPINIONS AND MODERATION
Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators.
SUPPORT THE FORUM
Unmannedspaceflight.com is funded by the Planetary Society. Please consider supporting our work and many other projects by donating to the Society or becoming a member.