IPB

Welcome Guest ( Log In | Register )

16 Pages V  « < 13 14 15 16 >  
Reply to this topicStart new topic
China to the Moon - Chang'e 1 and 2, Chinese unmanned lunar orbiters
Paolo
post Jun 28 2012, 07:41 AM
Post #211


Senior Member
****

Group: Members
Posts: 1377
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


--------------------
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 Jul 19 2012, 07:40 PM
Post #212


Senior Member
****

Group: Members
Posts: 1377
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.


--------------------
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 Jul 24 2012, 07:55 PM
Post #213


Senior Member
****

Group: Members
Posts: 1377
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


--------------------
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
Phil Stooke
post Jul 24 2012, 08:17 PM
Post #214


Senior Member
****

Group: Members
Posts: 5809
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.
Go to the top of the page
 
+Quote Post
tolis
post Jul 29 2012, 10:47 PM
Post #215


Junior Member
**

Group: Members
Posts: 92
Joined: 18-June 08
Member No.: 4216



QUOTE (Phil Stooke @ Jul 24 2012, 09:17 PM) *
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.
Go to the top of the page
 
+Quote Post
Paolo
post Aug 14 2012, 04:51 AM
Post #216


Senior Member
****

Group: Members
Posts: 1377
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


--------------------
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 Aug 14 2012, 01:53 PM
Post #217


Bloggette par Excellence
****

Group: Admin
Posts: 4503
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 blog - @elakdawalla on Twitter - Please support unmannedspaceflight.com by donating here.
Go to the top of the page
 
+Quote Post
SFJCody
post Aug 15 2012, 02:55 AM
Post #218


Member
***

Group: Members
Posts: 784
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
Go to the top of the page
 
+Quote Post
Paolo
post Aug 15 2012, 09:34 AM
Post #219


Senior Member
****

Group: Members
Posts: 1377
Joined: 3-August 06
From: 43° 35' 53" N 1° 26' 35" E
Member No.: 1004



QUOTE (SFJCody @ Aug 15 2012, 04:55 AM) *
PanSTARRS observations of Chang'e suggest it will be at Toutatis by December.


thanks! solid info at (long) last!


--------------------
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 Aug 20 2012, 11:43 AM
Post #220


Senior Member
****

Group: Members
Posts: 1377
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.


--------------------
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
climber
post Aug 20 2012, 02:55 PM
Post #221


Senior Member
****

Group: Members
Posts: 2640
Joined: 14-February 06
From: Very close to the Pyrénées Mountains (France)
Member No.: 682



QUOTE (Paolo @ Aug 20 2012, 01:43 PM) *
. The relative distance at closest approach will be about 11 km/s.

Interesting info biggrin.gif


--------------------
Go to the top of the page
 
+Quote Post
Phil Stooke
post Aug 20 2012, 02:57 PM
Post #222


Senior Member
****

Group: Members
Posts: 5809
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.
Go to the top of the page
 
+Quote Post
Paolo
post Aug 20 2012, 03:13 PM
Post #223


Senior Member
****

Group: Members
Posts: 1377
Joined: 3-August 06
From: 43° 35' 53" N 1° 26' 35" E
Member No.: 1004



QUOTE (climber @ Aug 20 2012, 04:55 PM) *
Interesting info biggrin.gif


oops...


--------------------
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 Sep 29 2012, 05:14 AM
Post #224


Senior Member
****

Group: Members
Posts: 1377
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


--------------------
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 Sep 29 2012, 08:45 PM
Post #225


Senior Member
****

Group: Members
Posts: 1377
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


--------------------
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

16 Pages V  « < 13 14 15 16 >
Reply to this topicStart new topic

 



RSS Lo-Fi Version Time is now: 24th November 2014 - 02:00 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.