CE-2 flyby of Toutatis |
CE-2 flyby of Toutatis |
Aug 25 2012, 04:27 PM
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#1
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Senior Member Group: Members Posts: 1729 Joined: 3-August 06 From: 43° 35' 53" N 1° 26' 35" E Member No.: 1004 |
I thought it was time to split the subject from the Moon forum.
Admins, can you move the relevant messages here? anyway, just out: an interesting blog article by Bill Gray explaining how he recovered the probe and how he computed the orbit yielding the 13 December flyby date Chang'e 2: The Full Story |
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Dec 11 2012, 06:04 PM
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#46
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Solar System Cartographer Group: Members Posts: 10185 Joined: 5-April 05 From: Canada Member No.: 227 |
15 years ago I made a map of Toutatis, using an experimental image interpretation method. It was never published because of a dispute about the validity of the concept I had devised. This is the map, in case anybody is interested. Apart from the concept I used to convert the geometry of radar images to the equivalent of visible images for mapping (that's where the dispute came in) I also tended to push my interpretation of craters too far in those days. Every little hollow became a crater in my map. Now I would be more cautious in my interpretation. (Note - rotation is about the long axis - and because of ambiguity in the images, this might be a mirror image of the real surface)
Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PD: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Dec 13 2012, 01:07 PM
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#47
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Senior Member Group: Members Posts: 1729 Joined: 3-August 06 From: 43° 35' 53" N 1° 26' 35" E Member No.: 1004 |
anybody knows whether ESA is providing tracking support to CE-2?
otherwise, has anybody tried computing the windows of visibility for the Chinese Deep Space Network stations? just to know when we can expect to have some news of the flyby |
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Dec 13 2012, 03:00 PM
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#48
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Member Group: Members Posts: 219 Joined: 14-November 11 From: Washington, DC Member No.: 6237 |
The images at http://echo.jpl.nasa.gov/asteroids/Toutati...2_planning.html get better every day. Will be really interesting to see how the delay-doppler representations compare to the visible light ones.
I just noticed the following on that page: "Scheduling update: due to an equipment failure, radar observations of Toutatis at Arecibo were cancelled." Not sure when this appeared... Can anyone explain what the potential impact could be on the observing campaign? Not that I'm complaining, the Goldstone quick results are great and impressive on their own. |
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Dec 14 2012, 03:57 PM
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#49
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Solar System Cartographer Group: Members Posts: 10185 Joined: 5-April 05 From: Canada Member No.: 227 |
I don't see anything in the online chinese press yet.
Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PD: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Dec 14 2012, 04:14 PM
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#50
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Senior Member Group: Members Posts: 1729 Joined: 3-August 06 From: 43° 35' 53" N 1° 26' 35" E Member No.: 1004 |
I have seen a release (in Chinese) on the site of the Chinese Academy of Sciences.
I don't have a link at hand, but it really didn't say anything new. |
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Dec 14 2012, 04:43 PM
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#51
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Member Group: Members Posts: 796 Joined: 27-February 08 From: Heart of Europe Member No.: 4057 |
I read on multiple Chinese pages, that they planned ~12 images of Toutatis.
But source is unknown, respectively it's some astronomer in Beijing. EDIT: Here is info from Chinese Academy of Sciences. -------------------- |
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Dec 14 2012, 05:46 PM
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#52
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Senior Member Group: Members Posts: 1729 Joined: 3-August 06 From: 43° 35' 53" N 1° 26' 35" E Member No.: 1004 |
be sure to check this!
http://www.youtube.com/watch?v=waH9zfEbNJs |
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Dec 14 2012, 06:51 PM
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#53
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Solar System Cartographer Group: Members Posts: 10185 Joined: 5-April 05 From: Canada Member No.: 227 |
The radar video is great - first time I have seen something like this, and it does a fantastic job of resolving the front-to-back ambiguity. In a still image you can often see two lobes appearing to intersect, but you can't tell which is in front and which behind.
Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PD: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Dec 14 2012, 07:53 PM
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#54
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Member Group: Members Posts: 796 Joined: 27-February 08 From: Heart of Europe Member No.: 4057 |
The video is great, but Toutatis looks somewhat distorted.
On every image all sides are doubled, so it looks like two overlaid images of Toutatis: -------------------- |
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Dec 14 2012, 08:05 PM
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#55
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Solar System Cartographer Group: Members Posts: 10185 Joined: 5-April 05 From: Canada Member No.: 227 |
That's because of the bizarre geometry of radar images. Imagine looking out over a range of hills with peaks at varying distances. Now imagine they are semi-transparent so you can see hills behind other hills. At the radar limb in these images, that is what we are seeing. The geometry is totally different from visible images. But with many images the ambiguities can be resolved - which is what this is all about, and why the Chinese images will be really useful. We have never had both high resolution radar and (reasonable resolution) visible imaging for any object before.
Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PD: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Dec 14 2012, 09:04 PM
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#56
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Interplanetary Dumpster Diver Group: Admin Posts: 4404 Joined: 17-February 04 From: Powell, TN Member No.: 33 |
Assuming it is better than the 2002 NY40 images, this could be significant.
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Dec 14 2012, 11:27 PM
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#57
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Junior Member Group: Members Posts: 86 Joined: 12-October 05 From: Beijing Member No.: 526 |
Video: http://news.cntv.cn/china/20121215/100850.shtml
Relative speed at 10.73 km/s Closest flyby at 3.2 km altitude Sequence (local time): • Dec13 15:25 Return solar panels to 180 degrees • Dec13 15:30 Switch to inertial attitude control • Dec13 15:45 Switch to star orientation 10 • Dec13 15:48 Switch to star orientation 2 • Dec13 16:20 Solar panel monitoring camera power up • Dec13 16:30 Closest flyby • Dec13 16:45 Solar panel monitoring camera power down Attached image: captured at 93–240 km distance between 16:30:09–16:30:24, maximum resolution 10 meters/pixel |
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Dec 14 2012, 11:30 PM
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#58
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Junior Member Group: Members Posts: 68 Joined: 15-June 12 From: Hong Kong Member No.: 6419 |
Just in from the Chinese news TV reports an hour ago: the fly-by was a success! The closest fly-by was at 08:30:09 UTC on December 13 at an altitude of just 3.2 km and at a relative velocity of 10.73 km/s. Quite a few photos were snapped by the CCD camera - including this series of photos taken 93 - 240 km away from Toutatis:
Chinese news report about the fly-by (may translate it later if I have time): http://news.cntv.cn/china/20121215/100850.shtml P.S. My first post here! (my interest in planetary exploration started in grade 1 after seeing photos from the twin Voyagers) -------------------- UMSF - the place of Opportunity to satisfy your Spirit of Curiosity via Perseverance
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Dec 14 2012, 11:35 PM
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#59
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Interplanetary Dumpster Diver Group: Admin Posts: 4404 Joined: 17-February 04 From: Powell, TN Member No.: 33 |
Woah! That is better than I was expecting. Welcome to the interplanetary club, China!
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Dec 14 2012, 11:56 PM
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#60
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Member Group: Members Posts: 796 Joined: 27-February 08 From: Heart of Europe Member No.: 4057 |
Fantastic and great news!
Now we have another country in "discovery" class! Congratulations! BTW, very nice surprise. Images are much better than expected. -------------------- |
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