[X] My Assistant

[Comga]

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Edit: looking more carefully, mentioned pixels are in fact "macro" pixel, probably artifacts resulting from some "bad" rescaling/magnification from original image. Using press release pixel, asteroid size is about 20x10; based on declared image size, asteroid measures 2x1 arcminutes or 580x290m at 1000Km, as expected.
Herebelow I magnified x2 the starting images, processed them in order to better see artifacts and real shape, then compare it with Oostro model (scale is 3 arcsec/pixel in all images). Agreement is good, but we still cannot see surface detail...
[attachment=1367:attachment]

First, I agree, this is tremendously exciting stuff. A fourth space program has returned meaningful remote sensing from deep in the solar system. With a little luck, it will keep getting better and better. If only their press releases matched their accomplishments.

As for the image scale, I count 19 "pixels" in the image, give or take one. If we use the 600 meter value and the 1000 km range, the individual "pixels" are 7.0 arc seconds or 34 microradians. This is very close to one third of the 100 microradian IFOVs of the camera (20.6 arc seconds). This is in agreement with their appearance as being oversampled from multiple images. In this case, it looks like they are trying to get 3X resolution. To me it looks like a "good rescaling", not a "bad" one. Of course, it would be better to have from JAXA the actual manner in which these images were prepared.

The attached image is a composite of the two, blurred with an 0.75 pixel radius Gaussian kernel (a matter of taste after a few tries). Details are not yet visible, but there are great hints as to the shape.

Attached image(s)

 

[dilo]

This is in agreement with their appearance as being oversampled from multiple images.  In this case, it looks like they are trying to get 3X resolution.  To me it looks like a "good rescaling", not a "bad" one.  Of course, it would be better to have from JAXA the actual manner in which these images were prepared.

Maybe they tried to make oversampled super-resolution image, but original pixel pattern appear too evident and masks finer details...

[Toma B]

Itokawa's rotation...

This site:
Rotation

Image:

[maycm]

That is so cool!

[RNeuhaus]

The asteroide Itokawa spins its axis every 12 hours. The spacecraft will have a hard time to approach it. The shape of the asteroide is not symmetrical and the Hayabusa's low speed ion engine to approach to the asteroide that cannot avoid it.

The rock might slam Hayabusa spacecraft. So it must land as close as possible at the rotation axis. Is that true or not? Otherwise Hayabusa can land anywhere. Will the Hayabusa spacecraft be able to thrust its ion engine in order to remain at the same position of Itokawa during its rotation?

Rodolfo

[Guest_Myran_*]

In response to RNeuhaus: Hayabusa will have to approach at the axis of rotation, or rather near that at least. The ion engine was used for the cruise phase reaching the asteroid and are turned of fnow I think.

[antoniseb]

In response to RNeuhaus: Hayabusa will have to approach at the axis of rotation, or rather near that at least.

If this rock is a few hundred meters long and spins once every twelve hours, I'm not sure that there's any special need to land near a rotational access point. How many meters per second will the surface be moving because of the spin?

BTW, the spacecraft haas chemical rockets for these manuevers.

[djellison]

Assuming an 800m sphere at 12hrs rotation ( which is probably ballpark-ish-right )

Circum= 2500 metres, so it's rotating at about 200 metres per hour - 3 1/3 per minute - - 5.5 cm / second

Doug

[tty]

Assuming an 800m sphere at 12hrs rotation ( which is probably ballpark-ish-right )

Circum= 2500 metres, so it's rotating at about 200 metres per hour - 3 1/3 per minute - - 5.5 cm / second

Doug

Putting Hayabusa in the way to be "swept up" may actually be a rather good way of effecting a soft landing!

tty

[ElkGroveDan]

Call me crazy, but the longer I watch this, the more I get the feeling that this looks like a "contact binary" body. Those lobes seem to jut off at a sharp angle -- maybe even three bodies in contact.

[antoniseb]

the longer I watch this, the more I get the feeling that this looks like a "contact binary" body.

Maybe. To me, the curved shape when seen the long way suggests one big piece. In any case, the craft should be just about on top of the asteroid now, and we'll probably get a good close image soon, and have more solid hints. Either way will be interesting.

[djellison]

Reminds me of a baby Eros, or even a bit like Comet Borrelly

[Toma B]

[SFJCody]

Reminds me of a baby Eros

They're both S-class, so it's possible...

[djellison]

Wow - it REALLY does...just 10 x smaller

http://near.jhuapl.edu/iod/20000121/index.html

Doug