Instrument commissioning phase, Beginning final approach to the comet Options

[Phil Stooke]

It's premature to decide that. We will have to see how the Rosetta team decide to do it. But the ends are not poles if the shape model rotation movie is showing us the correct rotation. In fact one pole appears to be in the deepest part of the neck.

This is a composite of the approach images.




Phil

[Holder of the Tw...]

... I nominate the smaller component as 'Klim' (less letters in the name) and the larger as 'Svetlana'.

It would help if we could find a full body portrait of the discoverers standing side by side. So far, all I can find on the web is for Svetlana Ivanova in this interview.

In fact one pole appears to be in the deepest part of the neck.

Yes, and where the terrain appear smoother than most of the comet. Slow movement, fairly smooth surface, dramatic views... this would be my bet for a landing area. Unless the soil is too loose to harpoon. Or there is too much outgassing activity in the area to be safe.

[Phil Stooke]

But that deep 'canyon' has a limited view of the sun - for power - and of Rosetta - for communications - so it's a bad location for a lander.

Phil

[Holder of the Tw...]

Are you sure about that? I'm not saying you're wrong (and maybe you've been talking to the right people). Just that if the spin axis is tilted toward the the sun (more or less) during the landing in November, you could pick an area that is in almost constant sunlight at one of the poles. Even if the crevasse was deep enough to cause some shadowing over part of the rotation, it might not be any worse than landing on any other part of the comet that is moving in and out of sunlight. And if the main spacecraft could station keep above the pole, I would think it would have an advantage in nearly constant communication.

It would help a lot to know just where the spin axis is pointing, but I don't know if the coordinates have been released.

Note: Yes, there were ground based estimates in 2012 that put the axis at RA = 40° ± 10°, Dec = 70° ± 10°, with a solar tilt of 40 degrees. But I'm saying I haven't heard whether the results from Rosetta's direct observations have been released.

[machi]

FOVs for all Rosetta's long range instruments (except OSIRIS WAC) from distance 100 km.
OSIRIS WAC has ~5× bigger FOV (side length) than OSIRIS NAC, so it's too big for this picture.

Attached thumbnail(s)

 

[Phil Stooke]

Not sure, just an educated guess. We'll see what the team have to say about it later.

Phil

[jasedm]

FOVs for all Rosetta's long range instruments (except OSIRIS WAC) from distance 100 km.
OSIRIS WAC has ~5× bigger FOV (side length) than OSIRIS NAC, so it's too big for this picture.

Brilliant Machi, and very useful - thanks!

[djellison]

And for those of us familiar with Cassini or MER/MSL sized sensors - good news...OSIRIS cameras are 2k x 2k (i.e. 4 megapixels)

Doug

[PDP8E]

Here is the Aug 4th 2014 NAVCAM
upsampled, deconvolved, and reoriented for sunlight from above...

[nprev]

Okay, THIS shot reminds me of two lumps of uncooked fudge batter side by side.

[PDP8E]

This is from the Aug 4th Navcam
This looks like a feature that is raised and could spew comet 'stuff'

[Hungry4info]

Any idea what these raised plateaus are? Water-poor regions that evaporated at slower rates while their water-rich surroundings evaporated faster?

[elakdawalla]

I think there have been a lot of ad-hoc explanations for different features on comets that are hard to validate. By orbiting a comet Rosetta will give us the first chance to take a look at these things from many sides, over time, to help us make some sense of these features. Getting more excited about this mission every day.

[wildespace]

Results of my stereo experiments. 3D images are based on best published OSIRIS and NavCam images.
One image in stereo pair is original OSIRIS image, second image is combined NavCam/OSIRIS synthetic image.
Credit for original images: ESA / Rosetta / NavCam / MPS for OSIRIS Team MPS / UPD / LAM / IAA / SSO / INTA / UPM / DASP / IDA.

Fantastic work! If you don't mind, here's a version of your anaglyph with stereo separation centered approximately on the comet's "neck". The larger half of the comet should now appear raised above the computer screen.



(The reason for this adjustment is that I like it when the red and cyan components of an anaglyph aren't removed too far from each other, effectively being easier to "combine" in your brain)

[Astro0]

Ongoing live coverage of Rosetta's arrival at Comet 67P C-G.

Streaming:http://rosetta.esa.int/

and on Twitter: https://twitter.com/ESA_Rosetta

Not long now