CE-2 flyby of Toutatis Options

[Phil Stooke]

Comparing the Itokawa radar images and shape model with the spacecraft images shows the limitations of using low resolution radar data. The basic size and elongation are well established but the two-lobe shape is not seen. For Hartley-2 two lobes are also resolved but not much more. But for Toutatis we have high resolution radar data and a detailed shape model, and nothing with that kind of radar data has been visited by a spacecraft. So this will be a very interesting encounter.

Phil

[JimOberg]

Technical info is great. Hsieh hsieh.

Big picture question: has anybody received any word about the health of the spacecraft in the past two months?

We're only days from the encounter. Is the absence of any news from China something to worry about?

[Explorer1]

The absence of news is business as usual over there. Has there even been an official announcement of this flyby yet from CNSA in Beijing?

[JimOberg]

The absence of news is business as usual over there.

I beg to differ. When things have been going well, China has released a stream of information, even ahead of actual events. They have been far more open then the Soviets were in Space Race days. I remember and can compare/contrast.

This silence is unusual.

[Explorer1]

Yes, I've read Don Mitchell's page on the old Soviet missions to the Moon and Venus, and the lengths he had to go to. I'm not sure if he posts on here, but I;m sure has has good insights too.
I'm just saying we should not get our hopes for a real crisp and immediate release like we've become used to from NASA or even ESA. I'd even be happy with a Halley's nucleus type blur.

[Paolo]

there was a long article on the development of CE-2 on a Chinese site recently
http://zh.cnr.cn/2100zhfw/zhhz/201211/t201...511342196.shtml and http://zh.cnr.cn/2100zhfw/zhhz/201211/t201...1342196_1.shtml
at a certain point it is stated (my adaptation of a google translation):

According to the latest news, Chang E 2 successfully completed further extend the test a second halfway correction, the whole control process satellite subsystems work properly, in good condition. Until October 9, Chang'e II satellite in orbit flight 736 days, has 2.61 million kilometers from Earth. Follow-up will be used to track and test our new two deep space monitoring stations and to carry out the technical test.

[JimOberg]

there was a long article on the development of CE-2 on a Chinese site recently

Thanks, Paolo, that's encouraging.

I also found this more recent URL but I can't get my translators to work:
http://news.e23.cn/content/2012-12-10/2012C1000084.html

[Paolo]

another long article in Chinese linked today on the 9ifly forum
http://y234.cn/?p=6128

[JimOberg]

another long article in Chinese linked today [url="http://bbs.9ifly.cn/thread-9843-109-1.html"]on the 9ifly forum [

I see a picture of chang'e-2 but can't get translator to work. Any help?

[stevesliva]

^ Google Translate
... seems to be a blogger asking similar questions. It appears based on english articles, so you get what we already know translated to chinese and then google-translated back. Wouldn't assume that will do anything but subtract information.

[elakdawalla]

Google translate worked for me. There's no new information in here -- in fact it links to Bill Gray's guest blog on planetary.org and to MPML. It provides background on Toutatis and on NEOs. Mostly it asks why the national space agency isn't ballyhooing this more, and then answers the question by explaining that Chang'E 2's ability to get good data on the encounter is limited, concluding that while any data will be interesting, the significance of this is more as an engineering test of the Chinese ability to make the encounter succeed, providing "valuable experience." Seems like a very nice explainer -- hopefully the author will get some traffic from Chinese readers

[JimOberg]

Google translate worked for me.

thanks. i agree that the technology demonstration of the SEL2 dwell, and the departure to the toutatis intercept point, are awesome new levels of space navigation capabilities. it would be nice to get images but your own blog put that in perspective.

i'm working to get my own media clients to appreciate the accomplishment and not to set artificially high success criteria.

would clementine have faced the same problem with asteroid imaging, or was its survey camera of a different design?

[mcaplinger]

would clementine have faced the same problem with asteroid imaging, or was its survey camera of a different design?

The Clementine cameras were all framing cameras with filter wheels, so no.

That said, slewing a pushbroom imager is not that big a deal; see http://mars.jpl.nasa.gov/mgs/msss/camera/i..._98_phobos_rel/ Of course I don't know how CE2's attitude control system works.

[Phil Stooke]

http://echo.jpl.nasa.gov/asteroids/Toutati...2_planning.html


New images appearing on this site now - one other difference between radar and CE2 images, worth remembering - the visible images will have MUCH better signal to noise - radar images are speckly and show very little detail near the terminator (except bits of it which are tilted towards the radar, like a crater rim) - in fact it's sometimes hard to see where the radar terminator is. So the new images really will be complementary in many ways.

Phil

[machi]

Very interesting images. Here is image pair from 9. December in more "visible" look:

Attached thumbnail(s)