Today a member of the camera science team put up the first images of the comet on his office door. So the camera works. He said on the image is M107 and the comet could this be?
here you go: http://blogs.esa.int/rosetta/2014/03/27/gotcha-rosetta-sets-sights-on-comet/
Hello again, Rosetta! Glad to see the cameras on Philae are checking out.
http://blogs.esa.int/rosetta/2014/04/15/new-mission-selfie/
I talked to a few engineers today and they say they are in the middle of the Lander checkout.
At a member's suggestion I've now created a dedicated Rosetta subforum. This should now be the active thread for Rosetta discussion. Instrument commissioning is almost over and there hasn't been much discussion, so this thread may morph into the comet approach thread.
Everybody should be reading http://blogs.esa.int/rosetta/ for detailed updates on the mission status; most are written by Emily Baldwin (Space Science Editor for ESA Portal, also @esascience). Including the attached new CIVA selfie, which is cooler in theory than in fact (it's low-res and awfully JPEGgy)
French organization http://smsc.cnes.fr/ROSETTA/GP_actualites.htm is also good source of news about Rosetta.
Here is for example color test image from Philae's ROLIS camera:
http://smsc.cnes.fr/IcROSETTA/results/Rolis_MLI_2014_04.png
On the image is Rosetta's Multi Layer Insulation.
Here is spectrum from Ptolemy:
http://smsc.cnes.fr/IcROSETTA/results/Ptolemy_2014_04.png
http://blogs.esa.int/rosetta/2014/05/14/rosetta-instruments-ready-for-action/
New pictures of C-G will be released soon.
And new images have been posted:
http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rosetta_s_target_comet_is_becoming_active
In short: The comet has started showing a lot of acticity and now has a clear coma. This mission is now getting really interesting to follow...
Also a reminder of how hot the Sun is.
The "Big Burn" is going very well, according to the Big Burn https://twitter.com/hashtag/BigBurn?src=hash.
Eight hours??? Wow!
Could anyone in the know explain why they chose this strategy instead of a bunch of smaller burns done earlier? Is this perhaps an engine duty-cycle thing or something like that?
EDIT: Or perhaps this is done now to facilitate a faster overall journey to the comet?
https://twitter.com/hashtag/Bigburn2?src=hashhas started.
http://blogs.esa.int/rosetta/2014/06/05/big-burn-2-complete/
Also, if you save up all that delta-v and just do one big burn you have little or no chance to fix any problems - an unexpected safing event for instance. Doing it in several steps lets you recover from any problems more easily.
The first two burns were by far the biggest. With them done successfully, it should be fairly smooth sailing now. And I would think we would be resolving the nucleus very soon. I am so looking forward to the first disk-resolved images.
Phil
OSIRIS will resolve nucleus at the beginning of July. In time of fifth burn (2.7.) Rosetta will be ~52 000 km from the comet and resolution will be ~ 1 km/pix (few image elements across cometary disc).
From the website
"Note: In fact, this variability in the actual thrust delivered versus what's planned is one of the reasons why the required orbit corrections are being done in a series of smaller burns. Any variation in one burn can be made up in the next, helping the entire process to be more efficient and optimise the use of fuel."
Big burn coming tomorrow:
http://blogs.esa.int/rosetta/2014/06/17/the-big-burns-part-3/
According to a reply on one of the comments there will be new images this week.
Less than one LD to go!
Churyumov-Gerasimenko on 4 June. quieter than before
http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rosetta_s_comet_expect_the_unexpected
Normal? Yes.
Impact the mission? No.
it's time we start taking bets...
will the nucleus look http://en.wikipedia.org/wiki/67P/Churyumov%E2%80%93Gerasimenko#mediaviewer/File:67PNucleus.jpg or http://www.aanda.org/articles/aa/full_html/2012/12/aa20116-12/F5.html?
OK, I'll go first. The old shape model, the first you linked to, is too symmetrical for my taste... I'm pretty sure that is an artifact of the modeling. So I vote for the second one. A digital Mars Bar to everybody if I'm wrong.
Phil
well i did post a celestia SPICE add on for this
in this thread
http://forum.celestialmatters.org/viewtopic.php?f=18&t=578
it is a synthetic noise added
http://www.imagebam.com/image/f50b75302911862 http://www.imagebam.com/image/7c7966302911878
The Original shape file
ftp://naif.jpl.nasa.gov/pub/naif/generic_kernels/dsk/churyumov-gerasimenko/
and
ftp://naif.jpl.nasa.gov/pub/naif/generic_kernels/dsk/churyumov-gerasimenko/input_files/
imported into blender
http://forum.celestialmatters.org/viewtopic.php?f=4&t=618
http://www.imagebam.com/image/c86760302732191
and the .obj file ( rotated to match the above plate file )
http://www.imagebam.com/image/b073c5302733121 http://www.imagebam.com/image/a4a65f302740136
We'll find out when we get there. Once that happens, perhaps there can be a meritorious discussion on the various means of establishing a shape model from light curves and how well they match the actual nucleus.
http://blogs.esa.int/rosetta/2014/06/25/comet-67pc-g-in-rosettas-navigation-camera/
Right, and see the associated note about data availability.
Phil
so in January/February we might have access to the data ,other than published news
I would urge caution in interpreting any data release schedule. The only thing we've learned over the 11 years since launch is that most of the instrument teams are in no hurry at all to release their data.
I have high hopes that at least the NAVCAM data will be available on that timeline, and today's release shows it'll be fun to play with. The distant approach phase is much more fun for a comet than it is for an asteroid, for sure!
http://sci.esa.int/rosetta/54220-comet-67pc-g-in-rosettas-navigation-camera/ as individual JPEGs (http://sci.esa.int/science-e/www/object/doc.cfm?fobjectid=54219). I spent a little while trying to make an animation where the background was black and star density nearer constant but couldn't produce anything I was happy with.
Emily, I tried too changing luminosity/contrast but resulting movie, reported below, isn't good... at least, it shows the increasing luminosity of approaching nucleus:
That's the closest I could get within a few hours:
http://imgur.com/tBSsi5i
The gif is reduced to 660 pixels to fit into the 2 MB limit (I think) of imgur.
I've used the average brightness of the images as brightness calibration, after subtracting the minimum brightness (RGB channel-wise) over all images (removes vertical streaky artifacts).
Then I (actually a quick and dirty written piece of software) subtracted the minimum brightness (again each RGB channel) over the thus far processed first 21 images to partially clean the images from camera artifacts. This latter processing step probably reduced the brightness of CG a bit more than intended in the beginning of the sequence, but using all images instead has no noticible cleaning effect at all.
I guess, that the overall dark raw images at the end of the sequence cause the flickering, when using the calibration method sketched above; but I had no better easy-to-implement idea.
Great animation, Gerald! It would be nice to change frames duration in order to have a constant star speed...
Good idea!
Here versions for roughly 5 ms and 2.5 ms per vertical pixel motion, hence no constant frame rate:
http://imgur.com/rBp9WXJ http://imgur.com/ckfx2aK
(The 2.5 ms-per-vertical-pixel version may be challenging for some computers.)
Looks like some frames would be missing; those gaps could be filled by interpolated frames, I didn't do so.
Did anyone watch the google hangout?
From here they talk about image release policy. http://youtu.be/Ey0UedaFaMs?t=38m25s
Getting closer!
Where is Rosetta? On 01 July 2014 Rosetta is 58,557 km from comet 67P/C-G and getting closer.
(ESA: http://sci.esa.int/home/ )
Phil
first hints of a shape
http://blogs.esa.int/rosetta/2014/07/03/the-comet-takes-shape-one-pixel-at-a-time/
hmm based on the public comments here http://www.bbc.co.uk/news/science-environment-28146472 ESA might need to release more images. Although for people with a casual or little interest in the mission, an occasional image each week is probably sufficient.
from http://blogs.esa.int/rosetta/2014/06/25/comet-67pc-g-in-rosettas-navigation-camera/
This is neat image from the Rosetta folks. One of the things I like to do in my outreach talks is give a sense of scale. This is an informative graphic in that regard.
It really is a flying mountain of ice and dust.
New images obtained on July 4:
http://blogs.esa.int/rosetta/2014/07/10/the-three-faces-of-rosettas-comet/
The comet's shape is starting to become apparent. Not unexpectedly, it's at least a bit irregular. Referring to the end of the text in the above link, I get the impression that it is more round/lumpy than long/skinny but I'd really like to know the phase angle in these images.
Thanks Bjorn for highlight.
Here below my processed version with gaussian de-pixelization and false-color coding... to me, it appear a tri-lobate shape (vaguely recalling a water molecule!) but we need to go a little bit closer to be sure.
Despite the appearance of complete over-exposure on the nucleus, there is some subtle detail which can be brought out by careful processing. But it may be spurious! - so you can't really interpret anything from it.
Phil
One more try, just to stimulate imagination, will be obsolete within a few days, certainly:
With those images being taken a week ago, I would bet they are probably resolving surface features now.
Shouldn't we have a new topic ?, we are past the commissioning phase.
This thread isn't very full yet, though it might need renaming to include approach imaging. I think it would make sense to start a new thread at the official date of the Mapping Phase, which is given http://starbrite.jpl.nasa.gov/pds/viewMissionProfile.jsp?MISSION_NAME=international+rosetta+mission as August 18.
***jaw drops!!!***
http://www.planetary.org/blogs/emily-lakdawalla/2014/07150633-quick-rosetta-update.html
https://www.youtube.com/watch?v=uQ9odfxkfRs
This is really wow!
I've taken this into account for a few seconds, and then ruled it almost out due to the rapid rotation, but missed to verify my presumption.
I'm sure it's now possible to calculate an estimate of the lower bound for the density of the comet not to break apart into a true binary.
... Which one is Churyumov, and which is Gerasimenko?
Wow, this is going to be an even more interesting mission than I was expecting. Interestingly, there are hints of the two components in Phil's and Gerald's heavily processed versions of the earlier images (although it was impossible to tell back then exactly what the images were showing).
Still nothing on the official ESA pages, or twitter for that matter! The video gas been removed from YouTube too...
I always wondered about the view from something like that trojan Hektor, and how it would be decades before anyone landed on something; guess it won't be that long after all!
Things could get VERY interesting dynamically when Rosetta achieves orbit. I wonder where the barycenter of the two 'lobes' is gonna turn out to be, esp. if there's a significant difference in density or internal material distribution between them. Might facilitate determining the internal structure of each quite a bit.
Don't forget that now we have an unexpected choice of landing, and Philae's anchors are looking (ironically) like a liability! No hopping around!
Just let it be somewhere in view of both components; it would be straight out of science fiction. Just serves to show how bizarre things can get in places of such low gravity.
There is a lot of interesting detail hidden in the bright areas. I'm not posting anything now, but if you can play with images, have a look. I will not post until an official release is available.
Phil
For a preview of surface views on a contact binary, you might enjoy these images from NEAR at Eros - not on the surface, but the low altitude makes it look similar.
Phil
http://near.jhuapl.edu/iod/20010108/index.html
http://near.jhuapl.edu/iod/20001212/index.html
To follow on from nprev's comment:
This may actually be good news for the Philea lander: it’s design was premised on a 40-fold lower gravity on the originally targeted comet 46P/Wirtanen.
On the other hand the odd shape of 67P-/CG that has now been revealed may pose a major new hurdle for the nav team: the nav camera’s must be able to keep the Philea landing ellipse in view at all time.
Exciting times ahead.. dictated by orbital mechanics Rosetta inexorably moves towards its destination (is “destiny” too much to say here?) and the Rosetta team has no spare time to park the issue and study it at length. Or perhaps this is already one of their pre-worked scenario’s - let's hope so!
Animated GIF by someone on the blog post:
http://i.imgur.com/4mClCsN.gif
well at least it is somewhat triangular the "lightcurve" shape file is a rough fit
the FIRST thing that came to mind is a line from a old 1962 comedy LP ( vinyl ) "the first family"
and a quote from it
"... and the rubber ducky is mine"
Looks like we were all in for a surprise
[/quote]
That is why we explore!
another http://www.cieletespace.fr/node/12004
the most interesting sentence states that two imaging sequences are now expected every week.
meanwhile, the Rosetta blog has http://blogs.esa.int/rosetta/2014/07/15/the-third-fat-burn/ on the latest braking burn
Just thought of an exciting possibility: What are the odds that the two lobes had significantly different histories before 'bonding', as in formed in different areas of the primordial nebula?
Probably not likely. However:
- The formative collision had to happen at fairly low relative velocity. That argues that they were neighbors, quite possibly siblings during their formation.
-Conversely, CG is now an inner Solar System object, and it most likely did not form in what is effectively our neck of the woods.
--If they formed in the Oort Cloud as neighbors & bonded, then they're stuck together real well since they almost certainly had to survive at least one encounter with Jupiter to achieve CG's present orbit.
--If they met & stuck together at or near where they are now heliocentrically, then they could have formed at different locations in the Oort. However, ending up in this state would be amazingly unlikely.
--Still, it seems at least as unlikely that they are fragments of an original object that calved during a close passage & subsequently reunited since they'd tend to drift apart due to independent outgassing events at the very least.
Bottom line here is that we've seen that a contact binary asteroid in the main Belt is not unusual because relative velocities are low between most of these objects. A contact binary comet in the same region does seem unusual, unless CG is an intermediate object between those two classes that formed in the inner Solar System.
Lots of interesting possibilities, and no doubt many future surprises ahead. This is gonna be a really, really fascinating mission.
http://en.wikipedia.org/wiki/Law_of_large_numbers make the unlikely happen.
Throw one dart; how likely is it to hit Bull's Eye from 5 meters distance?
Now repeat the same experiment 10,000 times.
From the large number of Oort objects and the http://en.wikipedia.org/wiki/Chaos_theory nature of http://en.wikipedia.org/wiki/N-body_problem like our solar system, a large number of scenarios are possible.
I'm sure we'll learn things we didn't anticipate, each of the next weeks.
The two parts look different in their shape: While the larger component is going to get a lenticular appearance with possibly a deep valley or a small third component, the smaller one seems to be more similar to a cube, possibly heavily cratered.
The roughly lenticular shape of the larger component might be the result of rotation during formation, whereas the smaller one may have rotated less, but may have experienced more collisions.
This is totally preliminary today, and we'll know much more within days.
http://blogs.esa.int/rosetta/2014/07/16/access-to-rosetta-data/:
I think the "unscheduled" release has been so widely distributed now that I can show my processing of it.
Phil
That's one of my processed versions
An animation of Phil's processed images with interframes to smooth out the action
Credit for the raw images: ESA / Rosetta / MPS for OSIRIS Team MPS / UPD / LAM / IAA / SSO / INTA / UPM / DASP / IDA
Is it just me, or does it look like the nucleus is precessing as well as rotating?
So exciting, this is shaping up to be a rewarding mission...
nprev, it's hard to tell from just one jerky rotation, but that might be possible. A slow rotator lacks the ability to stabilize its rotation axis so it can precess dramatically - asteroid Toutatis is a well-known example, comet Halley is another, and Saturn's moon Hyperion may be another (rather than chaotic as often stated, but this is perhaps still uncertain).
With a reported rotation period of more than 12 hours this might be another example, but I am not sure about that. We can't be looking down the rotation axis because of the changing shape, and we are not looking at the equator because features would just track side to side. I think we are viewing within about 20 degrees of 45 degrees latitude. That might be enough to account for the changing appearance.
Phil
http://en.wikipedia.org/wiki/Precession#Torque-free wouldn't be quite unexpected for a rigid, asymmetric body. But rotation period and precession period could well be no multiples. In this case we should note a jump in the motion (repeating the one-period loop).
New images are out:
http://blogs.esa.int/rosetta/2014/07/17/the-dual-personality-of-comet-67pc-g/
and finally, an official release from ESA:
http://blogs.esa.int/rosetta/2014/07/17/the-dual-personality-of-comet-67pc-g/
Interesting to read the different hypotheses regarding the shape, in the official ESA release:
1) two comets melding together
2) single comet gravitationally tugged into curious shape
3) ice evaporation
4) near-catastrophic impact
- We'll all be much wiser later on...
This is slightly changed version of the published animated gif. I've only added one synthetic frame (between 338° and 0°), changed speed and contrast and gamma.
(Credit for the raw images: ESA / Rosetta / MPS for OSIRIS Team MPS / UPD / LAM / IAA / SSO / INTA / UPM / DASP / IDA)
http://www.esa.int/spaceinimages/Images/2014/07/Rotating_view_of_comet_on_14_July_2014 grabbed and tiled:
http://imgur.com/JQroNdm
http://postimg.org/image/4tb1erbxl/full/.
Here a heavily processed version of the tiles, enhancing small features:
http://imgur.com/3frCQ0e
A tentative identification of some of the most distinct surface features in crops of these processed tiles:
Be careful. ESA posted an image that shows you the original resolution of the data. Most of the features that you've identified are barely more than one pixel across.
also that animation looks like it is FULL of jpg artifacts
What are the chances of this comet disintegrating when close to perihelion. Could these two pieces come apart?
Application of a data scrubbing algorithm yields surprising results...
the German DLR space agency has a large mosaic on its website:
http://www.dlr.de/dlr/presse/en/Portaldata/1/Resources/bilder/portal/portal_2014_3/CG_Mosaik.jpg
I guess we will just have wait and see, won't we.
And, darn it, I cannot get that song out of my head.
"Rubber duckie, your the one ...."
If you've seen Camel Rock Monument in northern New Mexico, you may be wondering if the camel has a counterpart in space: http://www.scenicusa.net/083012.html
Call for media: Rosetta’s comet rendezvous on August 6th
http://blogs.esa.int/rosetta/2014/07/18/call-for-media-rosettas-comet-rendezvous/
New Mexico? How about this one from the Libya desert, due South from Marsa El Brega on the road to Attahadi. It’s living proof that Nature is capable of stunning Duck renditions. An appetizer for what is yet to come from the Rosetta team?
A couple of parallel-eyeds based on the http://www.dlr.de/dlr/presse/en/Portaldata/1/Resources/bilder/portal/portal_2014_3/CG_Mosaik.jpg:
I agree with the idea it look a little bit like a rubber duck.
And I have to agree, we cannot say any features are seen from just single pixels in any images.
So just take a deep breath and wait a few more days for details to appear. =)
http://blogs.esa.int/rosetta/2014/07/24/hints-of-features/ from Rosetta!
Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
A strongly enhanced version:
We know distance (~5500 km) so resolution is slightly over one hundred meters per pixel (102-103 m/pix).
Images on the ESA's site are 8× magnified.
If you pay attention to last frame, there is a "welding" flat region between the two portions, made of darker material compared to the bright ring all around the contact; my impression about the "white collar" is that it could be made of fresh material exposed during last passages, when volatile substances (previously filling the gap between the two portions) sublimated; obviously, this idea is highly hypothetic! Only spectral analysis, joined to high-resolution morphology, could help to confirm or not this model...
Given the processing & enhancement done to these images & their size in pixels, is the resolution sufficient yet to determine if the albedo differences Dilo noted are real? For example, the bright 'ring' at the lobe contact point in particular sure looks like it might be specular; maybe the rest of the surface appears just as bright from the right illumination angles.
Very nice new images - here's a differently processed version.
Phil
Looks like new NAVCAM's will be given out daily from now to arrival. Better than OSIRIS weekly I suppose?
The shape model is interesting as well. It may be obvious to people but I should point out that the small peaks are artifacts - they are produced by the spatial interpolation process which converts a sparse set of points to a full DEM.
Phil
-- edit-
this is the OLD light curve shape file
are you referring to the nasa/jpl/naif shape file
http://www.imagebam.com/image/b073c5302733121
-- the NEW one ( early look)
the animation on the esa page
http://www.esa.int/spaceinimages/Images/2014/07/Shape_model_of_comet
The one just released by ESA, which contains several little spiky hills. I don't want people thinking they are real - for one thing the model is based on the earlier set of images with very low resolution. For another, most of the 'hills' are on the outer edge of the 'big end', which was hardly visible in the images because of the viewing angle.
Phil
This is more like the real resolution of the data. Not to deny the fantastic job the science team has done with such early data. I am only saying the high resolution rendering can't be relied on in every detail.
Phil
http://www.esa.int/Our_Activities/Space_Science/Rosetta/Call_for_Media_Rosetta_s_comet_rendezvous.
Good enough for me, and thanks for the translated information, Gerald. Nice catch, Dilo! This mission is growing more exciting by the day.
EDIT: If the impact precipitate origin of the bright area is correct, does that in turn imply that the barycenter of the two lobes is there? If so, this may be evidence that the smaller lobe is a bit denser than the larger one.
One can probably use the rotation video posted last week to determine the centre of mass of the system, and with that, a rough idea of the relative densities of the two bodies.
They can also use the spacecraft's own acceleration from C-G's gravity, measuring the radio signals once in 'orbit', (if one can call it that?).
This sounds astonishingly conclusive, since it doesn't need unlikely ad-hoc assumptions.
At the same time we've to check for possible alternatives not to draw premature conclusions.
Alternatives might be, starting from a single body, instead of a binary:
- faster abrasion of an asymmetric body due to higher average particle velocity at lower gravitational potential near the middle of the body, or
- lower albedo in earlier phases, hence higher evaporation near the center, for what-ever ad-hoc(?) reason, e.g. tholins or silicate dust due to rudimentary gravitational differentiation.
(There may be better ones.)
Alternatives will become less likely, if spectrometry returns a different composition of the two components.
If not, it may still be a contact binary with components of similar origin.
I think that global spectrometry cannot give proper answer to question if 67P is or isn't binary body.
Both parts must be covered by enough dust which probably prevents positive identification of valid differences between both parts.
It's a chance that we can see some differences in fresh parts of surface, but it depends on actual type of fresh surface.
I see as more promising future precise measurement of physical fields (gravitational, magnetic) and nucleus tomography by CONSERT experiment.
Hopefully there will be some nice jets of volatiles which can be compared compositionally for both units.
The PI of the Camera gave an interview, in German.
http://www.deutschlandfunk.de/rosetta-mission-ungewoehnliche-kometenform-reizt-die.676.de.html?dram:article_id=292776
There is a lot of meetings in front of the offices of the instrument PIs here at the MPS. It looks like the images generate a lot of activity from the CONCERT group and the the PIs of the Philae lander. The interior and the landing site were influenced by the fact that this thing is severely odd shaped.
If you make a nice film of the rotation put this in a computer model and get from this the center of gravity around which it rotates and from the images the volume at any given distance to the center, would it be possible to calculate the density difference of the comet? For the elongated asteroid Itokawa the MPS scientist did this already.
http://www.mpg.de/7899076/asteroid-Itokawa
Stone/Hungry4info, a simple rotation movie can give only informations on period of rotation and nucleus orientation relative to rotation axis; if you have good reference system (exact knowledge of spacecraft and nucleus positions) you can argue also absolute axis position and orientation, nothing more (at least on short intervals of observation). As you knows, such axis include the center of mass BUT you cannot say where exactly is this point, unless nucleus is subject to multiple rotations (precession).
For Itokawa, if you read article you linked, they argued the density heterogeneity by combining the informations on the shape (from Hayabusa) with Earth-based long-term observation of Yarkovsky effect!
Looks like a duck!
that is a "Duck" mesh with a normal map
A RUBBER duck!
http://blogs.esa.int/rosetta/2014/07/28/cometwatch-25-27-july/ from NAVCAM were published.
This is 5× magnified and slightly enhanced image from 27.7. Original resolution (without magnification) was 216 m/pix.
"Stairs" in the silhouette look like "jiggering" due to lower image quality in comparison to the OSIRIS images thus far. It's probably not real features.
Difficult to do any meaningful subpixel analysis.
But we can at least see, how the comet comes closer.
Edit: Here two strongly enhanced versions starting from the "full" images (no sharpening or hipass filtering used, just magnifying and overall brightness stretching), to mark the high-albedo zone, 26 and 27 July:
My stretchy version of all three new releases. Maybe that's another bright streak on two of them. Those two (on right) are close to zero phase by the look of it (spacecraft crossing the comet-sun line) so albedo differences show up well.
Phil
I believe their shape file is here : ftp://ssols01.esac.esa.int/pub/data/SPICE/ROSETTA/LSSP/LSSP_TEST/
as RS_GLOBAL_DTM_20m.ROS
(edit - that's a very old one - CREATION_DATE = 2014-04-30T18:11:30 )
RS_GLOBAL_DTM_20m.ROS
is old
the mesh in Blender
http://imgbox.com/tow9yCU6
file
"CSHP_DV_031_01_______00017.ROS"
is older
In the http://blogs.esa.int/rosetta/2014/07/29/cometwatch-28-july/ a region within the high albedo region looks particularly bright:
Exciting!
These Navcam views have a superficial resemblance to Vega images of Halley.
anticitizen2 says: "exciting!"
Yes.. when you see that thing hurtling towards you, all you can do is shout 'duck!'
Phil
BA-DUM TISH!
In the http://blogs.esa.int/rosetta/2014/07/30/cometwatch-29-july/ the brighter spot(s) within the high albedo region seem to be reproducible:
A crater/hollow on each component? OSIRIS can probably already see it...
"Emily's capitalization rebellion"
The first letter of each word SHOULD be a capital letter when removing the "blank space" in the name
it just makes READING the name( or variable) that much easier
As per Emily's blog entry, it would be interesting to calculate the gravitational field at the surface, if the newest shape model happens to be available in digital form.
yes, artifacts!
Phil
http://www.esa.int/spaceinimages/Images/2014/07/Comet_on_29_July_2014
The navcam image, attached, appears to show a ridge defining the edge of the material around the neck.
Slightly denoised version of the new image with some contrast enhancements:
Original image credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA.
I wasn't satisfied with previous denoised version because of subtle vertical artifacts (which are present in original image too).
So after some twiddling this is version without vertical artifacts. Now it's resampled to modest 20 meters per pixel.
Some data about the coma. Not very extended yet, but already visible.
http://blogs.esa.int/rosetta/2014/07/31/catching-up-with-the-comets-coma/
Regards,
Marc.
I expect there is feverish activity on the mission in terms of working out a landing site for Philae given the complicated gravity of the binary nature of the comet -my bet is that they'll opt for a landing on the flatter side of the larger component - less photogenic in terms of Philae's camera, but much safer in terms of achieving the sampling and in-situ measurements.
A quick size comparison with the Burj Khalifa, current tallest human-made structure.
That's the same conclusion I came to, but then I realized that that's the part of the comet that's moving (rotating) fastest. I was wondering if they'd prefer to land closer to a spin pole?
Hello to all
Here is my contribution to postprocessing of OSIRIS picture on July 29th :
It's going to become a rather complicated ballistic curve directed to a moving target, released from a moving Rosetta probe.
The goal has been to get close to a spot of activity, but not too close.
So I'd assume, that they'll first map the surface in very detail, then select a couple of scientifically interesting options, map them in high resolution, and after deciding the final target location (thus far as scheduled) they'll (numerically) calculate Rosetta's necessary motion to get a trajectory ending orthogonally on the surface, based on the measured and inferred field of gravity.
I'd think up to this point this can be done in a systematic way. A big unknown will stay the consistency of the surface material, which needs to be estimated to know how stongly the harpoons are allowed to be pulled back without detaching.
I can't predict where the landing will occur, but the only two missions which have tackled something like this are NEAR and Hayabusa, and they both landed in mid to low latitudes near the middle of a long side (I mean, not near the ends of the elongated objects). The poles on our comet, if the shape model shows rotation about the correct axis, are tricky - one is in the deepest part of the 'neck', the other is in a region we have hardly seen in images. The neck area is tricky from the point of view of communication and illumination - too many shadows and blocked signals. The other pole might be OK. Anyway, a fascinating problem to have.
Phil
I'm not sure how much the gravity field matters to the landing spot. The surface gravity is around 10^-5 m/s^2 (10^-6 g) which is neither a help nor impediment for landing. Even the rotation is probably not such a big deal as the relative velocity of the end of the elongated axis is around 0.25 m/s. I guess the issues of illumination and line of contact and the composition of the landing site and such matter more to the selection of the landing site.
Yes, the gravity is so gentle (remember Itokawa?) that Philae's landing springs and harpoons should handle a few centimetres tilt, as the ESA animation shows.
Still hard to believe it was designed when our best photos of a nucleus were Halley and Borelly...
The delta-v caused by gravity has been expected to make several decimeters per second. But one can know for shure only after measurements.
It matters in terms of aiming, since the "landing" will take several hours, and there is no propulsion with the exception of Philae's separation from Rosetta, and the final attachment to the comet's surface.
New image from Navcam.
http://blogs.esa.int/rosetta/2014/08/01/cometwatch-31-july/
http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rosetta_takes_comet_s_temperature
"ESA’s Rosetta spacecraft has made its first temperature measurements of its target comet, finding that it is too hot to be covered in ice and must instead have a dark, dusty crust."
An enhanced version of the 31 July NavCam image, and a false color image which combines two differently enhanced versions and an enhanced edge detection image:
Is this a new unreleased image? Looks different to me
https://twitter.com/AlanStern/status/495294591629684736
It's been deleted. Another inadvertent release, apparently. (When this stuff happens, as happened previously on Rosetta and with the Huygens images and the HiRISE image of MSL descending under parachute, my policy is to not post such images unless I see that the horse has well and truly escaped from the barn, at which point I will post it.)
So did anyone see it before it disappeared?
Interesting
I sure did, and I'm looking forward to being able to discuss it publicly when it or a similar one gets released next week
It seems like he got the lid on that tweet quickly. Monday and Tuesday should bring amazing views, though.
Here is the latest version of the approach sequence - using the raw images as I was having issues with their interpolated pictures
http://i.imgur.com/tjg4s0k.gif
http://i.imgur.com/tjg4s0k.gif
"So did anyone see it before it disappeared? "
Darn - I missed it! Very frustrating. Oh well, maybe it will come out next week.
Phil
It pays to stay up late sometimes; looks like they're posting NAVCAMS on weekends now!
http://blogs.esa.int/rosetta/2014/08/02/cometwatch-1-august/
A slightly lower phase angle makes the boulders and topography more visible....
I'm not convinced we're seeing any boulders. Any features that could be interpreted that way are only a pixel across, and a couple of them have huge contrasts between the "boulder" pixel and it's corresponding shadow pixel. I think it is more likely that we are too far to see boulders still (at least as of the 01 August 2011 NavCam iamge).
I don't see any clear boulders yet. All bright/dark 2 pixels features are probably specks of noise.
But this new NavCam image is really nice. With those shadows it actually shows more than OSIRIS image.
Today I saw a tweet referring to the orbit simulation from January –see link.
Perhaps superfluous to re-post here (amongst us – keenly interested) but anyway, here goes.
This simulation is somewhat outdated re. the geometry of 67P/C-G, but pretty much on the money re. the 12.3 hr rotation period (now 12.4).
If this simulation gives an accurate reflection of the Rosetta local orbit-speed relative to the pirouetting “duck” (for lack of a better word, sorry), then I will be highly interested to learn about the design of a viable Philea landing strategy. To me it looks an awesome puzzle; exactly the type of challenge that seems inherent to all frontier missions and that make it so rewarding for me to follow these exploits by the space mission experts.
At a recent Rosetta mini-conference in Amsterdam ESA’s Mr. Fred Jansen mentioned that an important mitigating factor to cope with all kind of as-yet unknowns is the “walking speed” of Rosetta relative to the comet – say 1m/s.
But imagine the relatively smooth comet (used in this simulation) replaced by the multi-angled and multi-faceted comet body, twisting & turning like a dance floor spotlight! I wonder whether the walking speed of the mother ship is in itself enough to drop the 1-axis stabilized Philea towards the chosen landing ellipse from the “design” distance, or whether Rosetta has to come a bit closer than originally foreseen. I understand that about 85% of all planned science return will be via Rosetta, with Philea the icing on the cake so to speak, so the safeguarding of Rosetta appears a real priority.
http://www.esa.int/spaceinvideos/Videos/2014/01/Rosetta_s_orbit_around_the_comet
The terrain really does look very 'comety' doesn't it? All those scarps and irregular flat depressions and things, few obvious impact craters. Is there a proper name for this kind of landscape? If not, there should be.
In parts it reminds me of Triton. Is Triton's landscape showing us what happens when comet-like processes take place on a world-sized body?
My guess is that the broad, flattened-crater-looking features we've seen on several comets to date are areas of sublimation, and thus possibly a landform unique to comets as a class of objects. I don't know if there's an official nomenclature for those; I'm gonna call them 'divots'.
"sublimation pan"
I thought of "scoop" to stay in tune with the icey nature of comets, but check the Rosetta blog right now! 5 min ago a new Osiris pic has been posted and the emerging details are spectacular.
I was just about to say the same thing!
http://blogs.esa.int/rosetta/2014/08/02/comet-at-1000-km/
The scarps, peaks and general appearance look like Wild 2, and maybe that smooth patch on the large part is a flow-like feature as seen on Tempel 1 and Borrelly.
Phil
The pictures are amazing, but I cannot wait until they stop interpolating them. At least previous releases were mostly interpolated by nearest-neighbor subsampling so you could generate the original pixels, but this one is a mess. I suppose they were in a hurry though!
I love the three pointy protrusions on the back of the duck's head!
Don't see any unmistakable impact craters in this view. IIRC, we really didn't see many on Wild 2, either. I wonder how long surface features persist on comets in the main Belt.
https://twitter.com/ESA_Rosetta/status/495598132491997184/photo/1
Trying anaglyph and x-eyed version, combining NavCam and OSIRIS:
Low sun angle I'll grant you, but it looks as if Philae lands on the 'pond' area of the 'ducks belly' there'll be a fair bit of local relief to look at.
P
In case there are more lurkers here as eager as I am to see the big picture - er, big video. http://www.esa.int/spaceinvideos/Videos/2013/10/Rosetta_s_twelve-year_journey_in_space
It's great to see the flight plan has worked so well!
Is it possible to extend the mission until the comet comes fairly close to Jupiter?
http://blogs.esa.int/rosetta/2014/08/03/cometwatch-2-august/ from the NavCam from distance 500 km.
Now there are some big rocks.
This version was interpolated to resolution 20 m/pix (original was 42,5 m/pix).
Credits: ESA/Rosetta/NAVCAM
At current resolution some of the irregular depressions with flattish bottoms remind me of the hollows found in places on Mercury and the Moon. Could they be the result of slow subsidence due to loss of volatiles from the interior?
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.
What a weird object.
http://blogs.esa.int/rosetta/2014/08/04/cometwatch-3-august/
Credit: ESA/Rosetta/NavCam.
That object toward the lower "front" of the larger segment is the first crater-like thing I think I've seen so far.
A false color version, including enhancements and sharpening:
It's based on the morphing one image to the second one. It's the same method which I used to obtain http://my-favourite-universe.blogspot.cz/2011/10/4th-5th-6th-7th-8th.html in high resolution.
Here is a screenshot how it looks in Sqirlz Morph.
Very interesting. I didn't know that software. I've been looking for something like that for a long time so I don't have to rely on the georectification software in GIS all the time.
Meanwhile here is our latest image enlarged and with the terminator brightened a bit to make subtle features easier to see there.
Phil
So, which end is Churyumov and which Gerasimenko? The larger and the smaller respectively?
Brief research reveals that the co-discoverers (male and female) were Klim Ivanovych Churyumov, and Svetlana Ivanova Gerasimenko, so I nominate the smaller component as 'Klim' (less letters in the name) and the larger as 'Svetlana'.
Here is my take on the latest navcam
...upsampled and deconvolved for sharpening...
also I rotated so that the sun is from the top which helps my built-in light/shadow perception
Terrific work, all; thanks for sharing it with us!
Finally see something that looks like an impact crater, central peak & everything...on the larger lobe in the middle of the flat region.
The "cratered" terrain reminds me of the back of a Suriname Toad, from which its young emerge at birth. These look like regions on the south pole of Mars where carbon dioxide is receding, leaving ever widening circular pans. The close nature of these cavities near the neck in particular may have more to do with venting than with formation by impacts. I wonder how long a crater would last anyway considering the rate of material loss from the surface. The original Deep Impact crater as imaged by Stardust's return mission was visibly "healed" only six years after its formation. I'm so anxious to peer deeper into these arenas!
There's a lot of interesting information about Rosetta on this page, including future plans, preliminary and early science results, light curves, simple spectra, etc.
http://www.lpi.usra.edu/sbag/meetings/jul2014/agenda.shtml
Another view: http://blogs.esa.int/rosetta/2014/08/05/cometwatch-4-august/
I'd be most grateful if one of our experienced topographers on the forum could help with an initial discussion of how to describe locations on this object. Do I call the middle section the saddle? Are the extremes of the dumbbell properly called the poles? The Japanese made it easy by comparing Itokawa with a sea otter, so they talked charmingly of its head, tummy and tail. Help me out here folks!
Several people call it a "duck" with head, neck, body.
Here a colorized (false colors from grey-scales), slightly enhanced, and sharpened version:
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.
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
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.
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.
Not sure, just an educated guess. We'll see what the team have to say about it later.
Phil
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
Here is the Aug 4th 2014 NAVCAM
upsampled, deconvolved, and reoriented for sunlight from above...
Okay, THIS shot reminds me of two lumps of uncooked fudge batter side by side.
This is from the Aug 4th Navcam
This looks like a feature that is raised and could spew comet 'stuff'
Any idea what these raised plateaus are? Water-poor regions that evaporated at slower rates while their water-rich surroundings evaporated faster?
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.
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
Rosetta has arrived at Comet 67P C-G, so time to start http://www.unmannedspaceflight.com/index.php?showtopic=7872.
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