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Philae landing on the nucleus of Comet 67P C-G
MarsInMyLifetime
post Sep 27 2014, 01:54 AM
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The latest NavCam composite shows that the left (main lobe) side of the valley seems to have cliffs with deep shadows, possibly vents. Now, seeing the line of boulders in the valley, I have a more distinct impression of gases from both sides of the valley impinging in the middle, creating on one hand a zone of stagnated velocities in which levitated boulders could lose escape velocity and drop down along that preferential zone, and on the other hand forming a plane of converged gas and dust. That plane would appear like a jet along the zone of impingement, and appear diffuse when viewed away from that plane. Just a thought, but it could explain why single sources for the "jets" have not been clearly identified yet, and why they appear variable based on direction.


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Phil Stooke
post Sep 27 2014, 03:12 AM
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That idea of jets forming where two or more broad cones of emission meet, channeling dust into sheets (two cones) or collimated jets (three cones) was referred to earlier in our discussions and originated with Jean Crifo 20 years ago (Icarus, 1995, v. 116, pp. 77-112).

Phil


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MarsInMyLifetime
post Sep 27 2014, 04:28 AM
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Thanks for the reminder, Phil. All very easy to visualize now.


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Paolo
post Oct 15 2014, 01:19 PM
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Site J confirmed as the landing site: ESA confirms the primary landing site for Rosetta
and we are given another image (actually a mosaic of two) from OSIRIS. (ADMIN EDIT) wink.gif
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MahFL
post Oct 15 2014, 01:44 PM
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It's not exactly flat is it ?
Those cliffs have to be at least 20 feet high ?
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centsworth_II
post Oct 15 2014, 03:56 PM
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On the left, the original ESA landing oval in white and my red ovals on the other two images. On the right, ESA's red circle marking landing site J on the latest image (rotated) with my green oval marking where I think the original ESA white oval would be located.
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fredk
post Oct 15 2014, 06:15 PM
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It's not clear these are landing error ellipses, since I couldn't see any such description in the captions of either image. The caption of the latest image just says
QUOTE
The circle is centred on the landing site and is approximately 500 m in diameter.


The cross marking the central landing position in the old image is pretty close (but not exactly) at the centre of the new red circle. There's no way to know if that's just plotting error or a slight adjustment in the central position.
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SpaceScout
post Oct 16 2014, 07:42 AM
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I have not seen this very high close up of the landing site J posted here, so here is the image in full resolution. Many wonderful details! thank you ESA


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Phil Stooke
post Oct 16 2014, 11:32 AM
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http://blogs.esa.int/rosetta/2014/10/16/la...tes-from-30-km/

The individual images for the Osiris mosaic of the landing area are here, plus - very nice - two images for site C as well.

Phil


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fredk
post Oct 16 2014, 02:49 PM
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Primary landing site in anaglyph stereo. There are severe distortions here and I've only done a quick a dirty job aligning the frames, so this may be headache-inducing:
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fredk
post Oct 16 2014, 02:50 PM
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And cross-eyed:
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fredk
post Oct 16 2014, 03:06 PM
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And a better-aligned crop of a scarp, showing precariously perched boulders/protrusions that couldn't exist in Earth-like gravity. Anaglyph:
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Cross-eyed:
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climber
post Oct 16 2014, 03:25 PM
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I'm wondering how far we'll see once on the ground. If we were to land on a perfectly flat surface, horizon would be very very close I believe, but on THIS, it's hard to predict anything.


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jhagen
post Oct 17 2014, 07:15 AM
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QUOTE (Phil Stooke @ Oct 16 2014, 04:32 AM) *
http://blogs.esa.int/rosetta/2014/10/16/la...tes-from-30-km/

The individual images for the Osiris mosaic of the landing area are here, plus - very nice - two images for site C as well.

Phil


Here's my version of a site J anaglyph...
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MahFL
post Oct 17 2014, 11:15 AM
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QUOTE (climber @ Oct 16 2014, 04:25 PM) *
I'm wondering how far we'll see once on the ground...


If we see something, it's going to be awesome. I would guess the horizon would be 300 meters away or so. The jets though should be something else.
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