IPB

Welcome Guest ( Log In | Register )

11 Pages V  « < 9 10 11  
Reply to this topicStart new topic
CE-2 flyby of Toutatis
ElkGroveDan
post Nov 22 2013, 03:11 PM
Post #151


Senior Member
****

Group: Admin
Posts: 4636
Joined: 15-March 05
From: Sloughhouse, CA
Member No.: 197



QUOTE (Explorer1 @ Nov 21 2013, 12:19 PM) *

Be careful, you can't believe everything you read on the internet.


--------------------
If Occam had heard my theory, things would be very different now.
Go to the top of the page
 
+Quote Post
elakdawalla
post Nov 22 2013, 03:51 PM
Post #152


Bloggette par Excellence
****

Group: Admin
Posts: 4259
Joined: 4-August 05
From: Pasadena, CA, USA, Earth
Member No.: 454



QUOTE (Paolo @ Nov 21 2013, 10:22 PM) *
one of the papers at this year's IAC had a closest distance of 1,564 +/- 10 m. from the center of mass, I think

That's pretty amazing considering the long axis is 4.5 km.

QUOTE (ElkGroveDan @ Nov 22 2013, 07:11 AM) *
Be careful, you can't believe everything you read on the internet.

rolleyes.gif


--------------------
My blog - @elakdawalla on Twitter - Please support unmannedspaceflight.com by donating here.
Go to the top of the page
 
+Quote Post
Paolo
post Nov 22 2013, 05:31 PM
Post #153


Senior Member
****

Group: Members
Posts: 1306
Joined: 3-August 06
From: 43° 35' 53" N 1° 26' 35" E
Member No.: 1004



I checked the paper "Relative Distance Estimation Between the Asteroid 4179 and Chang'E II Based On Spaceborne Opitcal Images" and it states:

QUOTE
the distance of the relative motion curve from the centroid of Toutatis to Chang’e II, i.e., their actual fly-by distance, is calculated.


so they are indeed not determining the distance from the surface. and later they conclude

QUOTE
the actual fly-by distance is 1564 m±~10 m.


note also that the paper by Huang et al referenced by the Icarus paper is this one: http://tech.scichina.com:8082/sciE/CN/abst...act511202.shtml


--------------------
I'm one of the most durable and fervent advocates of space exploration, but my take is that we could do it robotically at far less cost and far greater quantity and quality of results.

James Van Allen
Go to the top of the page
 
+Quote Post
Paolo
post Nov 22 2013, 05:33 PM
Post #154


Senior Member
****

Group: Members
Posts: 1306
Joined: 3-August 06
From: 43° 35' 53" N 1° 26' 35" E
Member No.: 1004



by the way, Huang et al. (page 600) state, google translated:

QUOTE
Flying over the nearest point from the target time: 770 ± 120 m;
Distance from the geometric center of the overflight time: 1.32 km ± 120 m;


--------------------
I'm one of the most durable and fervent advocates of space exploration, but my take is that we could do it robotically at far less cost and far greater quantity and quality of results.

James Van Allen
Go to the top of the page
 
+Quote Post
elakdawalla
post Nov 22 2013, 06:36 PM
Post #155


Bloggette par Excellence
****

Group: Admin
Posts: 4259
Joined: 4-August 05
From: Pasadena, CA, USA, Earth
Member No.: 454



Thanks very much for digging those up! I will add those details into my blog post.


--------------------
My blog - @elakdawalla on Twitter - Please support unmannedspaceflight.com by donating here.
Go to the top of the page
 
+Quote Post
Paolo
post Dec 12 2013, 05:47 PM
Post #156


Senior Member
****

Group: Members
Posts: 1306
Joined: 3-August 06
From: 43° 35' 53" N 1° 26' 35" E
Member No.: 1004



another (open access, this time) paper on the scientific results of the flyby
The Ginger-shaped Asteroid 4179 Toutatis: New Observations from a Successful Flyby of Chang'e-2


--------------------
I'm one of the most durable and fervent advocates of space exploration, but my take is that we could do it robotically at far less cost and far greater quantity and quality of results.

James Van Allen
Go to the top of the page
 
+Quote Post
Dysgraphyk
post Dec 13 2013, 04:58 PM
Post #157


Newbie
*

Group: Members
Posts: 9
Joined: 27-August 12
Member No.: 6618



according to this paper

QUOTE
Chang'e-2 implemented the flyby on 13 December 2012 at 8:29:58.7 UTC at a closest distance of 770 ± 120 (3σ) meters from Toutatis' surface at a high relative velocity of 10.73 km s−1,


quite a close shave... blink.gif


--------------------
Go to the top of the page
 
+Quote Post
Paolo
post Dec 13 2013, 05:04 PM
Post #158


Senior Member
****

Group: Members
Posts: 1306
Joined: 3-August 06
From: 43° 35' 53" N 1° 26' 35" E
Member No.: 1004



QUOTE (Dysgraphyk @ Dec 13 2013, 05:58 PM) *
quite a close shave... blink.gif


it still surprises me that they seem to have done it entirely without optical navigation. they just knew the exact orbit of the asteroid thanks to radar tracking and that of the probe thanks to ranging and they managed to pull out the closest flyby ever with these data


--------------------
I'm one of the most durable and fervent advocates of space exploration, but my take is that we could do it robotically at far less cost and far greater quantity and quality of results.

James Van Allen
Go to the top of the page
 
+Quote Post
ElkGroveDan
post Dec 14 2013, 12:58 AM
Post #159


Senior Member
****

Group: Admin
Posts: 4636
Joined: 15-March 05
From: Sloughhouse, CA
Member No.: 197



QUOTE (Paolo @ Dec 13 2013, 09:04 AM) *
....they just knew the exact orbit of the asteroid thanks to radar tracking and that of the probe thanks to ranging and they managed to pull out the closest flyby ever ....

There probably was some serendipity involved.


--------------------
If Occam had heard my theory, things would be very different now.
Go to the top of the page
 
+Quote Post
Paolo
post Dec 14 2013, 08:41 AM
Post #160


Senior Member
****

Group: Members
Posts: 1306
Joined: 3-August 06
From: 43° 35' 53" N 1° 26' 35" E
Member No.: 1004



actually, they had a trajectory correction (and a sizeable one, 3.3 m/s) the day before the flyby, so I guess they were aiming for a very close encounter on purpose


--------------------
I'm one of the most durable and fervent advocates of space exploration, but my take is that we could do it robotically at far less cost and far greater quantity and quality of results.

James Van Allen
Go to the top of the page
 
+Quote Post
Paolo
post Apr 10 2014, 05:28 PM
Post #161


Senior Member
****

Group: Members
Posts: 1306
Joined: 3-August 06
From: 43° 35' 53" N 1° 26' 35" E
Member No.: 1004



a paper on the future orbit of CE-2, due for publication in the Chinese Science Bulletin: The Earth co-orbital motion and recapture of the Chang'e-2 spacecraft


--------------------
I'm one of the most durable and fervent advocates of space exploration, but my take is that we could do it robotically at far less cost and far greater quantity and quality of results.

James Van Allen
Go to the top of the page
 
+Quote Post

11 Pages V  « < 9 10 11
Reply to this topicStart new topic

 



RSS Lo-Fi Version Time is now: 20th April 2014 - 01:20 PM
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 a project of the Planetary Society and is funded by donations from visitors and members. Help keep this forum up and running by contributing here.