China to the Moon - Chang'e 1 and 2, Chinese unmanned lunar orbiters |
China to the Moon - Chang'e 1 and 2, Chinese unmanned lunar orbiters |
Jun 28 2012, 07:41 AM
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#211
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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 |
at last the story has been picked up by Chinese news sites!
http://tech.sina.com.cn/d/2012-06-27/14427317706.shtml nothing new as far as I can tell from the Google translation, beside the first mention of a planned flyby distance of 1000 km. I also find it interesting that they mention a flyby near the end of this year or early next year, as if the date was not yet fixed |
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Jul 19 2012, 07:40 PM
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#212
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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 |
still nothing new on CE-2 to Toutatis, so I was performing some calculation.
I found the specs of the camera in the paper Overall scheme and on-orbit images of Chang'E-2 lunar satellite CCD stereo camera. It is quite different from the camera on CE-1. It consists of a refracting optics mated to two 6144 pixel linear arrays: a forward looking and a rearward looking one. at a distance of 1,000 km from Toutatis, each picture will be 430 km wide and will have a resolution of 70 m per pixel. Unfortunately, the linear array camera is well suited for an orbiter, but not for a flyby probe. either CE-2 will have to rock back and forth to build images, or it will have to collect long swaths as the asteroid crosses the field of view. Moreover, it is not particularly suitable for optical navigation. In any case, I would not expect more than a handful of pics. Data return should be slow but not painfully so. At L2 CE-2 returned data at 750 kilobits per second, and some 20 times more distant at Toutatis it should return at several kilobits per second, comparable to Stardust. |
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Jul 24 2012, 07:55 PM
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#213
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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 am puzzled... Chinese news sites are now reporting a Toutatis flyby in March next year instead of January!
see for ex http://news.sina.com.cn/c/2012-07-25/021924837262.shtml |
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Jul 24 2012, 08:17 PM
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#214
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Solar System Cartographer Group: Members Posts: 10184 Joined: 5-April 05 From: Canada Member No.: 227 |
That must be wrong - Toutatis will be very far away by then. I would guess a reporter misunderstanding. I am assuming the spacecraft will remain in the vicinity of Earth and probably return to the Earth-Moon system later, though no idea yet what its fate will be.
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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Jul 29 2012, 10:47 PM
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#215
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Member Group: Members Posts: 149 Joined: 18-June 08 Member No.: 4216 |
That must be wrong - Toutatis will be very far away by then. I would guess a reporter misunderstanding. I am assuming the spacecraft will remain in the vicinity of Earth and probably return to the Earth-Moon system later, though no idea yet what its fate will be. Phil Hopefully adding some confidence to the details of the encounter: The event is mentioned in the Goldstone radar's schedule: http://echo.jpl.nasa.gov/asteroids/Toutati...2_planning.html It must be on then.. Regards to All, Tolis. |
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Aug 14 2012, 04:51 AM
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#216
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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 |
actually, I wrote an email to the guy who maintains the JPL asteroid radar site last month and he told me that he has no first-hand info. all he knows about the flyby is what can be learned from Emily's blog
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Aug 14 2012, 01:53 PM
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#217
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Administrator Group: Admin Posts: 5172 Joined: 4-August 05 From: Pasadena, CA, USA, Earth Member No.: 454 |
OK, that's funny. The Wikipedia effect at work.
I have spoken with American scientists working with the Chinese on this flyby, so it is for real, but I have no more details than I did before. -------------------- My website - My Patreon - @elakdawalla on Twitter - Please support unmannedspaceflight.com by donating here.
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Aug 15 2012, 02:55 AM
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#218
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Member Group: Members Posts: 813 Joined: 8-February 04 From: Arabia Terra Member No.: 12 |
PanSTARRS observations of Chang'e suggest it will be at Toutatis by December.
http://www.projectpluto.com/pluto/mpecs/cheprobe.htm |
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Aug 15 2012, 09:34 AM
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#219
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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 |
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Aug 20 2012, 11:43 AM
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#220
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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 |
the Project Pluto page has been updated:
QUOTE You can fit an orbit to the current (as of 18 August) observations and get a positional match, at 08:27 UT on 13 December, within better than an arcminute, with a close match in distance as well. Toutatis comes to its closest approach to earth (0.046 AU) on the preceding day. meanwhile I have received an email from a Chinese engineer working on orbit design for CE-2. although he did not give me the precise date, nor the targeted flyby distance, he told me that the encounter is expected to take place 7 million kilometers (0.0468 AU) from Earth, which closely fits the 13 December date. Some more details on orbital design: CE-2 entered solar orbit directly from L2, without any Moon or Earth flybys, with a delta-v of several m/s. At the end of the L2 "excursion", the remaining delta-v was about 120 m/s. Four course corrections will precisely target the Toutatis flyby and establish a geometry that's convenient for imaging and communications. The relative speed at closest approach will be about 11 km/s. |
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Aug 20 2012, 02:55 PM
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#221
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Senior Member Group: Members Posts: 2922 Joined: 14-February 06 From: Very close to the Pyrénées Mountains (France) Member No.: 682 |
. The relative distance at closest approach will be about 11 km/s. Interesting info -------------------- |
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Aug 20 2012, 02:57 PM
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#222
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Solar System Cartographer Group: Members Posts: 10184 Joined: 5-April 05 From: Canada Member No.: 227 |
We should probably move this section of the thread to a dedicated asteroid section.
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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Aug 20 2012, 03:13 PM
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#223
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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 |
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Sep 29 2012, 05:14 AM
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#224
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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 |
google translation of an interview with Ouyang Ziyuan on Chang'e 1 and 2 lunar science and data mining
http://translate.google.com/translate?hl=e...ved=0CE8Q7gEwAg |
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Sep 29 2012, 08:45 PM
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#225
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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 |
and a related youtube video
http://www.youtube.com/watch?feature=playe...;v=w58_INahqpk#! it looks like poster presentations at some kind of congress |
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