Philae landing on the nucleus of Comet 67P C-G |
Philae landing on the nucleus of Comet 67P C-G |
Nov 17 2014, 03:20 PM
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#676
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Member Group: Members Posts: 547 Joined: 1-May 06 From: Scotland (Ecosse, Escocia) Member No.: 759 |
So is Philae at rest at 15:43 in the latest image, or still going? Here's the 15:43 location in wider context (red dot): [attachment=34318:philbounce.png] In that last cut-out image of Philae over the shadowed area (at 15:43), it still has a long way to go. It will travel for a further 1 hour and 49 mins before reaching its final resting place at 17:32. |
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Nov 17 2014, 03:45 PM
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#677
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Forum Contributor Group: Members Posts: 1372 Joined: 8-February 04 From: North East Florida, USA. Member No.: 11 |
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Nov 17 2014, 03:48 PM
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#678
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Forum Contributor Group: Members Posts: 1372 Joined: 8-February 04 From: North East Florida, USA. Member No.: 11 |
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Nov 17 2014, 03:53 PM
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#679
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Founder Group: Chairman Posts: 14431 Joined: 8-February 04 Member No.: 1 |
There are various papers that explicitly states the gear is designed to take the landing loads, but could well bury itself (the landing gear) in the process.
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Nov 17 2014, 04:01 PM
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#680
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Member Group: Members Posts: 201 Joined: 16-December 13 Member No.: 7067 |
New version with a very un-scientific cutout of Philae from the 15:23 frame 11 minutes before touchdown.
Didn't resize Philae even though it would be about half a kilometer farther away If Philae came in from the left, it looks like it dragged its two left feet. There may something similar in the right foot, but it is less apparent. |
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Nov 17 2014, 04:09 PM
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#681
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Member Group: Members Posts: 547 Joined: 1-May 06 From: Scotland (Ecosse, Escocia) Member No.: 759 |
I think the bigger central depression is actually the main Philae body rather than a leg.
The fourth smaller trailing mark, which is either a double or triple cluster of little depressions, is the last leg to hit with less force, after the other two and the body took the brunt of the (gentle) impact. |
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Nov 17 2014, 04:12 PM
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#682
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Junior Member Group: Members Posts: 33 Joined: 15-April 09 From: Wilmington, NC U.S.A. Member No.: 4738 |
Based on the new OSIRIS images, it appears Philae is heading in a different direction then proposed by the initial CONCERT prediction (i.e. the blue diamond).
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-Ned |
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Nov 17 2014, 04:17 PM
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#683
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Member Group: Members Posts: 547 Joined: 1-May 06 From: Scotland (Ecosse, Escocia) Member No.: 759 |
No, I think we are seeing Philae on a curved track passing through different altitudes, viewed obliquely. So we cannot infer the ground track from that.
Hence a straight line drawn from the initial touchdown point to the 15:43 position does not give us the direction of travel. |
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Nov 17 2014, 05:00 PM
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#684
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Junior Member Group: Members Posts: 33 Joined: 15-April 09 From: Wilmington, NC U.S.A. Member No.: 4738 |
ADMIN EDIT: Unnecessary quoting removed. Please be mindful of rule 3.5
Yes, Philae could definitely be on a curved track. However, as far as the obliqueness of the view goes, the view is from above looking down to the north (relative to the image). So in the image at 15:43 the lander is actually more south relative to the the ground then appears in the image. Of course I could have the geometry all wrong, but that's how I see it -------------------- -------------
-Ned |
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Nov 17 2014, 05:10 PM
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#685
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Senior Member Group: Members Posts: 4246 Joined: 17-January 05 Member No.: 152 |
I've approximately registered the two first bounce site navcam frames and the post-bounce OSIRIS frame - here's the resulting animation:
There are a couple of things of note. First, comparing the navcam "dustcloud" frame with the OSIRIS frame, you can see that the dark splotch extends towards the bottom of the frame from the actual touchdown triple mark. This is consistent with the splotch being the shadow of dust kicked up by the bounce, given that the sun is shining from roughly the top of the frame. The other thing is that there's no hint of the triple bounce mark in the other navcam frame, although if you look around the frames other features of similar size and contrast are (barely) visible in that navcam frame. Of course it might just be a coincidence of pixel noise cancelling out the triple mark in the navcam frame. But I still wonder if the PS in the caption of this post, which says the other navcam frame was actually taken an hour after the bounce, is incorrect. Notice that the other text on that page and on this image page posted after the blog post still state that the other navcam frame was taken before landing. Also, I can't see any change in shadows between the two navcam frames, whereas if they were taken an hour apart there should be a large change - that's one twelfth of a C_G day. |
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Nov 17 2014, 05:13 PM
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#686
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Senior Member Group: Members Posts: 2918 Joined: 14-February 06 From: Very close to the Pyrénées Mountains (France) Member No.: 682 |
More picts of Philae before and after landing: http://blogs.esa.int/rosetta/2014/11/17/os...ross-the-comet/
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Nov 17 2014, 05:25 PM
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#687
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Member Group: Members Posts: 547 Joined: 1-May 06 From: Scotland (Ecosse, Escocia) Member No.: 759 |
Yes, Philae could definitely be on a curved track. However, as far as the obliqueness of the view goes, the view is from above looking down to the north (relative to the image). So in the image at 15:43 the lander is actually more south relative to the the ground then appears in the image. Of course I could have the geometry all wrong, but that's how I see it I thought the same at first, but I think the orbiter is roughly following Philae's ground track because the 3 prior photos are lined up with each other and the landing site. Rosetta's camera is therefore looking more or less straight down. After the first touchdown this all changes, and Rosetta continues upwards towards the top of the picture, and is therefore looking somewhat back (down towards the bottom of the picture) at an increasing angle post-landing. Of course Philae could also have bounced off in a somewhat different direction from its line of approach. |
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Nov 17 2014, 05:41 PM
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#688
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Junior Member Group: Members Posts: 54 Joined: 10-August 11 Member No.: 6119 |
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Nov 17 2014, 05:45 PM
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#689
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Founder Group: Chairman Posts: 14431 Joined: 8-February 04 Member No.: 1 |
Nice GIF, Jam Butty
One could almost speculate that the slab like 'rock' on the SW corner of the touchdown point has been kicked up significantly by bounce 1 - perhaps it kicked the lander to a harder 'slap down' with the other two legs which triggered the bounce. |
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Nov 17 2014, 05:53 PM
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#690
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Administrator Group: Admin Posts: 5172 Joined: 4-August 05 From: Pasadena, CA, USA, Earth Member No.: 454 |
I wonder if Philae's shadow is visible in any of the OSIRIS images. It wouldn't be in the tight frames they cropped, but it's worth looking for.
Given that we have SPICE information, I'm wondering if someone could produce a table giving altitude and sub-spacecraft lat and lon for both Philae and Rosetta in 5-minute time steps for the landing phase? -------------------- My website - My Patreon - @elakdawalla on Twitter - Please support unmannedspaceflight.com by donating here.
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