http://www.esa.int/SPECIALS/Mars_Express/
These images, taken by the High Resolution Stereo Camera (HRSC) on board ESA’s Mars Express spacecraft, are Europe’s highest-resolution pictures so far of the Martian moon Phobos.
http://www.esa.int/SPECIALS/Mars_Express/SEM21TVJD1E_0.html
Here's a Mars Express Phobos image from orbit 1607- a distant view. There is a close view on this orbit, but I haven't got the patience to download 600 Mb of mostly dark sky.
Phil
What is it with the PDS/PSA and their total hatred of Zip/Rar/GZ'ing files that actuall comrpess REALLY well...
At least the small bodies node have the right attitude for this stuff.
Doug
Waaw thanks for sharing those!
Mea culpa - I see now that the second image from that orbit, the 600 MB file, is of Mars, not Phobos.
Phil
600 MB? The biggest Phobos images from that orbit are about 2 MB. Where were you looking? I was on the PDS Geosciences node.
Here are the two highest resolution images from this orbi (1607).
http://img134.imageshack.us/my.php?image=1607expresspda4.jpg
I checked this after reading your question, Ted. The Data directory has the full res images, and for the largest image from that orbit it says:
Wednesday, April 26, 2006 6:49 AM 697587740 h1607_0009_nd2.img
697 Mb. But I was mistaken in thinking it was Phobos, I assumed that without checking - the second set of images from 1607 are of Mars. Even so, the largest Phobos image on that orbit, the nd2 image, is 9548940 bytes. Your images are the "super-resolution" images which are a lot smaller.
There are some very similar images of Phobos in orbit 1574 as well.
Phil
- and another in orbit 1558, but this one is from orbit 1212, the nadir (nd2) image:
I'm still exploring the Mars Express Phobos images. This, I think, is the highest resolution image yet, from orbit 756. The original file was 169 MB, but largely dark sky. I have played with the contrast a bit to brighten the terminator. Several blocks casting shadows can be found along the terminator.
Phil
Nice image, Phil. Where do the JPEG-ish artifacts come from, was this one lossy compressed before transmission?
No, I compressed it severely to reduce the file size for posting on UMSF.
Phil
Very impressive shot, Phil... resolution should be around 3m/pixel!
The file you posted is only 460k, I think is worth to re-post a less compressed version... please!
sorry, wrong re-post.
I will put the uncompressed image on an external website tomorrow.
Phil
Good point, Ted - actually I'll be reducing it to 8 bit after a judicious contrast stretch (actually 2 different contrast stretches merged), and then saving it as a high quality jpg, so it will be compressed, but a lot less than my post.
Phil
Oh, that's a nice one, Phil!
Are you methodically posting every halfway decent Phobos image here or are you just making selections of your favorites?
--Emily
I'm not being methodical, I'm just playing. I needed a break from more serious stuff. But I'll probably end up posting any decent Mars Express pics as I find them.
Phil
Good grief! Is it my imagination, or are there really two sets of grooves in the image that Phil just posted, intersecting at right angles?
How does this tally with the theory that the grooves were produced by interactions between Phobos and debris in orbit around Mars?
Ian.
Despite impeccible logic and analysis "proving" how the grooves were formed by impacting debris, I just don't believe it. Yah... one group from 10:00 clock to 4:00 clock and a second finer set from 1:00 clock to 7:00 clock angle. _AND_, roughly bisecting them at an angle of 5:30 to 11:30 clock angle is a non-groove linear splatter pattern that looks like it *IS* splatter-cratering from a jet of debris.
Good catch on the splatter pattern Ed. That certainly does look more like a crater chain from a debris or cometary impact.
Here's a link to the higher quality Phobos image posted above. It's reduced from 16 to 8 bit, cropped and saved as a high quality JPG, so it is compressed but not too badly. The 16 to 8 conversion was done twice, once to favour dark areas, and the results merged using my secret sauce recipe. I'll keep this up here for a few weeks and then remove it so get it while it's hot.
Phil
http://instruct.uwo.ca/geog/136a/hrsc756_phobos.jpg
I've mirrored it here...
http://s3.amazonaws.com/planetary/10212/hrsc756_phobos.jpg
--Emily
Phil, do you know the pixel scale on that particular image from orbit 756?
The PDS label says 5.9 m/pixel. and roughly 5000 pixels across 30 km seems to support that value.
Phil
Thanks for the great image Phil, I hope one day you will reveal your secret sauce recipe...
(I was wrong about image scale because I estimated it using Phobos mean radius instead of diameter)
Here's a nice new Phobos image from Mars Express, orbit 3909:
Out of curiosity, how are things going with mapping of Phobos? The best global map I've seen is the USGS airbrushed version. FWIW, my mapping software is approaching the point where I can consider utilizing more general shape models, vs a simpler triaxial ellipsoid.
I should have added to my previous post - it came from one of the abstracts at the ESA Mars Conference - see thread under Conferences. Willner et al., in the Friday Workshops.
Mapping - there has been no serious work since Viking. I've been saying for years that I'll make a new global mosaic with the best images, but other things have prevented me. But I will certainly do so when Phobos-Grunt flies, or if CSA's PRIME gets funded. The abstract above refers to a new global shape model, which will help improve the next round of mapping.
Phil
Wow, Phil, that's a really cool image, thanks for pointing it out!
--Emily
... and add a bit of colour, just 'cos it's Sunday night and there's nothing on telly until Medium comes on...
Great stuff, Phil & Stu!!! Now I know exactly how Phobos must have appeared to the crew of the spacecraft Rolling Stone as it approached Phobos in Heinlein's immortal novel...absent the industrial complexes and filled landing berths, of course...
Quick inspiration:
we sense therefore we are
unmanned and alone
solitary robots peer deeply into the Unknown
seeing, tasting, hearing that which no human has yet known,
like a splash of water or blast of radiation
on tender skins
We, safe in the cradle, see vistas dreamed of
yearned for, in our infant dreams
by generations denied their future by tumult,
by the restless and capricious nature of our species
by priorities, set too often by
those who cannot see far horizons,
even through eyes of silicon, gallium arsinide, feed horns and reflectors...
blindness is inexcusable
as the spectrum of the Universe unveils itself, reluctantly,
as bigger than our minds
what challenge, what wonder, can possibly compare?
we must see, at least
in order that someday we may touch
I found it in the place mentioned in post 30, above.
Phil
Here's the direct link to the http://www.rssd.esa.int/SYS/docs/ll_transfers/project=MarsEXPRESS&id=2778599.pdf (PDF).
--Emily
Shall be interesting to see what shape model results Willner et al. are going to present at the November conference.
Seeing that image I wonder who launched that potato into low Mars orbit anyway ?
Dr. Willner said I'd need to ask Neukum directly for permission to post that other image, but he pointed out one that had been released on the Web in February (apologies if someone else already posted this elsewhere):
http://www.dlr.de/DesktopDefault.aspx/tabid-3432/3681_read-7819/gallery-1/gallery_read-Image.1.2995/
--Emily
Wow, that's a gorgeous picture of Phobos, thanks for the link Emily... that one passed me by, somehow...
That picture was around for quite a while now: http://www.unmannedspaceflight.com/index.php?s=&showtopic=3946&view=findpost&p=84812
Here are a couple of Mars Express HRSC images of Phobos, from the PDS courtesy of G. Neukum. They have had a bit of extra processing in my usual manner to brighten the terminator area.
Phil
That's something with three different orientations of grooves I can see in the top image...
It is already gridded, it will be easy for Phil to make us a new model and map.
At first glance, I thought we were looking at it through a screen door.
The High Resolution Stereo Camera (HRSC) on Mars Express is not the best instrument.
Orbit 3802, Phobos, image h3802_0003_sr2
HRSC itself is great, but the super resolution bolt-on camera from which those two frames came from has never achieved good focus.
Doug
Mars Express (MEX) release #2.
February 14, 2008
http://pds-imaging.jpl.nasa.gov/Admin/resources/cd_mex.html
Orbit 3310, Phobos, image h3310_0000_s22
Another high (??) resolution image.
Orbit 3769, Phobos, image h3769_0004_sr2
I don't think it's motion smear, more like noncircular PSF due to out of focus deformity in some part of the optics. It gives an appearance of vertical motion smear. It would probably be possible to do a proper deconvolution if we knew the PSF exactly (say by imaging a star), but as I recall the amount of defocus isn't constant either.
It certainly is not motion smear, but it does look like it because there is a 'double exposure' effect. Regardless, they are still nice images in other respects, and are being used to improve the shape model of Phobos (The other HRSC images are less useful for that because they are from a scanning rather than framing camera). The top one just above is inside Stickney. These pics come in sets of 4 or 5 making up strips across the surface, and would make nice mosaics.
Phil
the S12 image is pushbroom.
PSF = Point Spread Function. i.e. the contribution of surrounding pixels to the pixel in question. With accurate info on that, you can subtract it all back out again..ish...roughly.
Doug
Here is a quick attempt. There does seem to be motion blurring in some of the data, almost as if it is a double exposure with one of the two slightly smeared in a direction almost but not quite perpendicular to the direction of the double exposure offset.
i am wondering the nature of these phobos and deimos releases… are these just additional images they captured last year but we just hadn’t seen them until they released the full sets of data?
They were, for the most part, not in official releases, but were in the raw data release. Much of this has been available via ESA's PSA for a long time.
Mars Express to rendezvous with Martian moon
http://www.esa.int/SPECIALS/Mars_Express/SEMVGAWIPIF_0.html
16 July 2008
Scientists and engineers are preparing ESA’s Mars Express for a pair of close fly-bys of the Martian moon Phobos. Passing within 100 km of the surface, Mars Express will conduct some of the most detailed investigations of the moon to date.
The series of fly-bys will take place between 12 July and 3 August. During the second encounter, the spacecraft will fly within 273 km of the surface. Six days later, Mars Express will close to within just 97 km.
Although the Red Planet itself has been studied in detail, very little is known about the origins of its moons, Phobos and Deimos. It is unclear if the moons are actually asteroids that were captured by Mars’s gravity and never left its orbit. Another possibility is that Phobos and Deimos are actually surviving planetesimals, bodies which formed the planets of the Solar System. They may also be remnants of an impact of a large object on Mars.
As Mars Express closes-in on Phobos, the data gathered will help scientists answer these questions.
"As it flies by at a distance of 97 km, Mars Express will image areas of Phobos that have never been glimpsed before. "
... by Mars Express. The whole surface of Phobos was imaged by Viking.
Oh for a Deimos encounter.... there's a world we really do need new images of.
Phil
Yes, particularly the trailing hemisphere.
Does anyone know when those images from the 97 km flyby will be made available?
Uh.... <Ahem!> Well, um...that's a pretty good question, and all I'm gonna say.
Agustin Chicarro (project scientist) told me they were supposed to be downlinked Friday, and that there should be some images released on Monday.
--Emily
00.12... bye bye Monday...
Maybe tomorrow...
He said Monday, but he didn't say which Monday
Hungry, just so you know (if you don't already), releases from ESA can be a bit erratic for a whole lot of known and unknown reasons that I definitely don't want to get into for reasons of forum decorum and that have been extensively discussed previously. Gotta wait & hope, is all.
Just heard back from the ESA Media office...
"We are still waiting for the material, but expecting to receive the first images by the end of the day or tomorrow.
We will publish them on the web (link below) as soon as possible (tomorrow or Thursday the latest).
http://www.esa.int/esaSC/index.html"
unnecessary quoting removed
Thanks Stu,
I was beginning to wonder also. Does anyone know what the resolution of the images at closest approach will be, 1 metre per pixel, better, worse? Hopefully we'll get some more insight as to where Phobos camefrom.
Captured type D asteroid?
Formed around Mars?
Formed from impact ejecta from Mars?
My bet is still option 1, despite the difficulties with explaining orbital mechanics, but I still think, Phobos is as alien to Mars as the spacecraft we have sent.
It will be interesting to compare the new Phobos imagery with the NEAR / Shoemaker spacecraft imagery of similar resolution of asteroid 433 Eros.
Perhaps Mars Express could do similar with Deimos? Comparisons with the MARSIS & multispectral imagers / spectrometers of the two would be most fascinating.
Andrew Brown.
Using spice kernels (for the spacecraft, Mars and Phobos) I tried to simulate the Mars Express Phobos flybies.
Underneath the images of how Phobos would approximately look like at closest approach.
The field of view in these images is 30 degrees (I don't know what field of view Mars Express has).
17 july 2008 (273 km)
width of the HRSC swath is about 12 degrees - covering 5000ish pixels.
Doug
A photo of Phobos quoted to have been made during the 93 km flyby last week was published
in the Nature & Science section of todays Frankfurter Allgemeine Zeitung, a major German newspaper.
G. Paul, who is frequently writing about space topics there, gave some general information about
the moon and a hint, that the photos cover the proposed Phobos-Grunt landing site.
This might be an indication that some release of data is near.
Best,
Oliver
If I read that correctly, the headline says "Over Mars: A Cosmic Potato Named Phobos"? Hilarious!!!
Yes, the translation of the title is correct .
So can we nickname Phobos-Grunt "SPUDnik?" *ducks*
http://www.dlr.de/en/Portaldata/1/Resources/portal_news/newsarchiv2008_4/grunt_01_phobos_flyby.jpg.
Images appearing now.
Andrew Brown.
Here is the link to the press release:
http://www.dlr.de/en/DesktopDefault.aspx/tabid-1/86_read-13161/
I don't know about distortion -- Phobos looks pretty distorted in general; I can tell you from experience that it can be really hard to tell whether you have an oblique perspective or if an image has been unequally stretched. But I have a different question. There are two image releases that lack annotations. I thought that maybe they were the two views that had been combined to create the stereo image. But it appears that they are in fact the same image, stretched differently, and it seems that there was a gap in the image, some kind of data dropout, that was handled differently between the two images. In one the gap was closed, making an obvious seam; in the other, the gap was filled by duplicating pixels. I think that's what's going on anyway -- do others agree? The two pictures are
http://esamultimedia.esa.int/images/marsexpress/401-20080729-5851-6-na-1a-Phobos-Flyby_H1.jpg
and
http://esamultimedia.esa.int/images/marsexpress/401-20080729-5851-6-na-1b-Phobos-Flyby_H1.jpg
Odd.
--Emily
The opposite of a usual activity: take apart an anaglyph to get its separate frames and voila, two more HRSC images of Phobos. Here's the red channel:
Interesting, the relatively small number of the tiniest craters. The dust layer must be mighty thick.
Really cool anaglyph on the home page - it really leaps off the screen at you!
I just had a really dumb idea, looking at that moon again. I was noticing how much it resembled the rocks around Opportunity at Victoria, and I started thinking...Hmm, what if those grooves were caused by differential micrometeoroid weathering due to layers? They do resemble at a macro scale the aeolian cross bedding we've seen before. That would add weight to the "Phobos is a chunk of Mars" idea!
The best (for me) explanation I've heard for the grooves so far was highlighted http://www.planetary.org/blog/article/00001391/ as being the result of Phobos sweeping up ejecta in chains from Martian impacts. Scroll down on the linked article to see a computer simulation which is a good match to the observed grooves.
But looking at the latest pictures, they seem to be far too straight and of regular width to be secondary crater chains - looking much more like collapse features to my untrained eye.
The mystery remains....
In Astronomy & Astrophysics: http://www.aanda.org/articles/aa/abs/2008/34/aa09787-08/aa09787-08.html
Mayby grooves on phobos seem not to be due to secondary impacts from asteroid impacts on Mars; they are too defined and regularly for that. These computer simulations seems to give only the trajectory of the ejected masses but the the width of the shower. And there are too much of these grooves and they are too regularly placed. This counts for some effects connected with material resistance against stress forces per length unit.
Especially, one set of grooves seems to be more or less concentric or better: coaxial along the Mars-anti-Mars-axis and can be explaned easily with tidal effects. The "craters" along the grooves may be simply sinkholes, especially because there are no ejecta. The other set of grooves (here highlighted in red) is nearly perpendicular to the other one and can be formed earlier by the same way; a large impact may have altered phobos orientation by chance and after that tidal fractures occure in a new set. So, that older bunch of grooves is orientated around the old Mars-anti-Mars axis of Phobos. Here:
http://www.planetary.org/blog/article/00001391/
or here
http://www.lpi.usra.edu/meetings/lpsc2006/pdf/2195.pdf
You can see the both sets, but you need another cartographic projection to see the old set as a concentric/coaxial one as well as the other.
Both groove sets are not (the old one) or not well (the new one) converging to two points but slicing phobos more like a cut potato. Here, the non-sperical shape of phobos and cartographic problems with this fact should be considered; the pseudo-convergence is an articfact of the cylindrical projection!
I would also consider that Phobos had been in an elliptic orbit first, so diffential stresses du to the tidal force change between apoareum and periareum and libration (nodding) effects due to the constant rotation period and the inconstant orbital angular velocity would have forced a result. A large impact, mayby the Stickney forming impact, would have altered the meanwhile circular orbit to an elliptic one again and it altered Phobos spin and orientation. So a second set of grooves came to existence.
You may recognize that the younger grooves, which are mostly sharper defined and smoother than the older ones (red) cross through them (and not opposite) which will give a hint which groove set was the former one.
The Stickney-impact itsself may be "buffered" by the weak material itsself, like the craters on asteroid Mathilda, and does not harm the whole structure. It is like shooting a projectile in styrofam...
It would be interesting to look for some grooves on several other moons like Amalthea; in the Saturnian system so much dust maybe hide features like that on the innermost moons.
Interesting article about Phobos on the ESA website, based on the recent flyby:
http://www.esa.int/SPECIALS/Mars_Express/SEM8MUSG7MF_0.html
In the article just quoted by charborob, there is an animation of Mars Express being diverted from its orbit during a close pass by Phobos. The interesting thing about this simulation is the way MEX returns to its original orbit after the deviation. It looks kind of like the maker of the simulation has added the symmetric plot of a normal distribution to the original unperturbed track of the spacecraft. Is this really how it would happen, or would the spacecraft experience a permanent change in its orbit due to the small gravity assist derived from Phobos? Observatoire Royal de Belgique must know a lot more than most of us about orbital mechanics, but maybe in this case they are pulling our legs and expecting us not to notice?
I checked "forgotten" Mars Express archive and I stated that this year Phobos has been photographed several times. Unfortunately, the quality is not stunning.
I like the last two transit images! More close passes would certainly be nice, especially if they showed the Phobos-Grunt landing region better.
Phil
Transit image modified to show the Martian surface better.
Why is the Martian surface so dark in those transit images? Is it because we're on the nightside of Mars' terminator?
The shading suggests that's not right.. not near-terminator either. Maybe it's the filter?
Phil
Couldn't the skylight provide some illumination, mainly from the west, even past the terminator? Didn't one of Dawn's Mars flyby images capture a similar scenario?
[quote name='peter59' date='Nov 12 2009, 07:16 PM' post='149916']
Oh... thanks a lot, Peter, I do not deserve so much after all those years, but I like very much your Phobos pics selections ! Thanks again for sharing those with us
...And, Peter, here is your image fully colorized. Enjoy !
The craters in the background sure look weird! This isn't a snapshot, of course; time as well as distance are covered along the long axis of the image, and the spacecraft was clearly doing something odd as it was setting up to track Phobos. But I don't understand what was happening to make the craters appear smeared in a stepwise fashion.
Anyway, cool colorization, Olivier.
I wonder if it's a bit like the way Mars stops, goes backwards, then carries on, night to night in the night sky.
Retrograde craters - I think you've got it, Doug.
Phil
That's a really stunning image! Which orbit is the colourised shot from? I can look up our attitude profile and see what might be causing the crater distortion (although I think you've already guessed it!).
"Phobos & Deimos visible in same image for first time"
http://www.dlr.de/en/desktopdefault.aspx/tabid-1/9600_read-21513/
Remarkable footage to say the least although I expected Phobos to pass even faster throught the image:
Images every 0.1s - slowed significantly in that animation - not surprising it comes across as 'slow'.
If someone fancies putting two copies of the animation together with a one frame time difference that might work as a crosseye 3D animation.
Here is the ESA page on the images: http://www.esa.int/SPECIALS/Mars_Express/SEMDOE7JT2G_0.html
"For the very first time, the martian moons Phobos and Deimos have been caught on camera together. ESA's Mars Express orbiter took these pioneering images last month. Apart from their ‘wow’ factor, these unique images will help the HRSC team validate and refine existing orbit models of the two moons."
More information about how they got the images are on the page. Very cool sequence.
The image caption says "http://www.dlr.de/en/DesktopDefault.aspx/tabid-1/9600_read-21513/gallery-1/gallery_read-Image.8.12354/." It seems like whoever wrote the press release failed to understand the significance of the last three words.
Well I can confirm that consecutive frames from this image sequence make very good 3D pairs, so I'm going to have one more go. This time not a suggestion but a request - on bended knee - a 3D animation please!
Have we ever had a 3D animation from spacecraft images here? Maybe it would be a first.
Mars Express is scheduled to make the closest Phobos flyby at 50 km on March 3.
http://www.esa.int/esaMI/Mars_Express/SEMDUGSJR4G_0.html
My earlier work on Deimos was the construction of a global photomosaic. The shape model it was based on was by Peter Thomas of Cornell, the leading person in this kind of work, and it used Viking images. The shape model is not ideal - a large region near 270 W longitude has only ever been seen in one image, so no stereo for shape modeling at all. We badly need a future mission to provide new imaging of Deimos.
i thought it was from the Viking images
mine is a hand drawn height map converted to a 3ds model
well a mission there will solve the problem
From AW&ST next issue: "Mars EXpress has begun a series of new flyby of Phobos...at its closest encounter, on Mars 3 the probe will come to within 50 km. (31 mi.) of the Martian moon..."
The latest post on the http://webservices.esa.int/blog/blog/7 has this information:
"New webpages went online today allowing anyone to download data from the digital terrain model of Phobos created by the EuroPlanet project..."
The links for downloading the DEM is at the bottom of http://europlanet.dlr.de/node/index.php?id=214.
Animated flyover anyone?
i just answered a question on this over at shatters.net
and a very quick pds to png convert of
base_dtm_phobos.pds
[attachment=20838:base_dtm...obos.cub.png]
the above image WAS "normalized " 0 to 256
a better one
from the pds > cub ( ran fx on it os the values are from 1098 to 6585) > exported to 16bit tif > to rgb normalized png
[attachment=20839:base_dtm_phobos.png]
Nice one ...
Hey, it's not that bad. Remember Deep Impact, which also wasn't allowed to take photos at closest approach, because of the risk of debris damaging the camera? We still learned a lot about Tempel 1 anyway!
Why not risk the camera, at that time no follup-mission was planned.
Ofcourse, the impact still had to be photographed.
It wasn't that taking photographs was prohibited - it was that the spacecraft had to orient itself to protect itself during the closest approach because of cometary particles etc, and then continue departure imaging thereafter. It was protecting the entire spacecraft so it could finish its mission, not the camera.
http://www.nasa.gov/mission_pages/deepimpact/timeline/index.html
"Flyby spacecraft enters shield mode"
The actual closest flyby altitude was ultimately 67km due to an engine overburn ... http://webservices.esa.int/blog/blog/7
New SPICE kernels are in as well, taking us to 20Mar and hence the remaining close flybys. Just to add confusion, the table below states UTC times and not ephemeris times as my earlier table:
Some early pictures are released
This image was taken 656km across.
The grooves are beginning to look more like crater chains.
They couldn't take images in this sequence because MEX had to be in "passive mode" for accurate tracking for the Phobos-gravity experiment.
IIRC, this flyby was over the night side, so the images wouldn't have been too enlightening anyway.
Edit:
peter59 already said that.
It's late, so take this thought experiment as woolly night owl speculation;
We apparently are seeing 'ring residue' on Rhea's surface from a rather tenuous, but seemingly fairly organized orbiting system. Now imagine for the moment, a mini sub-moon (like maybe in the 1-2km range) placed ~~1000km above Rhea's equator. What does the 'ring residue' look like if it 'splats' onto the 1-2 km sub-moon ? (or more precisely, what does the sub-moon look like after it is splattered)
(I think the size of the sub-moon might need to be closely constrained, I am trying to minimize shepherding effects)
Plausibly Phobos-like, or completely un-Phobos like?
Could dust (crud) knocked off Deimos organize to the extent of the Rhean residue, apparently detected by Cassini's MIMI instrument, on it's way spiraling down to Mars ?
Date Altitude (km) * Instruments used during flyby
16 February 991 PFS, SPICAM, ASPERA
22 February 574 PFS, SPICAM, ASPERA
25 February 398 PFS, MARSIS
28 February 226 PFS, MARSIS
03 March 50 MaRS, ASPERA
07 March 107 HRSC, OMEGA, MARSIS, SPICAM, ASPERA
10 March 286 HRSC, OMEGA, MARSIS, ASPERA
13 March 476 HRSC, SPICAM, PFS, ASPERA
16 March 662 HRSC, SPICAM, PFS, ASPERA
19 March 848 HRSC, SPICAM, PFS, ASPERA
23 March 1341 Not used
26 March 1304 HRSC, SPICAM, PFS,
John W,
I would expect the deposition of ring material to build mountains, not canyons (see Atlas, Pan).
Unless it was less of a ring and more of an asteroid belt.
New massive batch (2010-02-17) - orbits 6402-7094
Too much noise for my limited skills to bring out anything notable on the night side.
How would that explain the closeness of the craters (Surely, the impactors would have spread out)? How would that explain the presence of the linear features all over Phobos? What about the lines that cross and curve?
Hungry4info
a late night thought
but i do think they are the result of tidal stress
[attachment=20947:12_13phobos1.png]
i have been working on something else and came across a "crater chain "
luna north pole but ...
http://www.imagebam.com/image/ab9b4470788964
Absolutly stunning images from orbit 6906 (21.05.2009)
2592 x 2248 pixels
"I thought there was a theory that the sets of parallel lines were caused by ejecta from impacts on Mars? "
There was - still is in some minds, but I've never felt it was very satisfactory. My preferred idea is that the grooves are the surface expression of jointing (families of intersecting fracture planes) in the interior, possibly caused by large impacts, though not necessarily Stickney (the south polar depression is probably a very old crater larger than Stickney). They might also be caused by pressure release after excavation from the interior of a parent body, and opened by later impacts. The porosity we now expect can be explained as caused by open jointing.
Phil
Another stunning images from orbit 6916 (23.05.2009)
5184 x 5040 pixels
..... and from orbit 6926 (26.05.2009)
5184 x 2728 pixels
Wow, ESA just won a little more of my heart.
Even so, they are new to me.
Could the tidal fracture interpretation of the linear features on Phobos explain why some of the close lines are slightly curved and intersect each other? Or why the linear features are seen across the entire moon? I was browsing through the Phobos images I've so far downloaded over the years and came across this one. It hurt my confidence in the tidal fracture hypothesis.
Looks like some large boulders rolled or bounced on the surface of Phobos, possibly disappearing in space afterwards
Hi, I've been lurking here a while but at last I've been prompted to post.
The old images of Phobos set me thinking again about the grooves. I worried about them for months a few years back. Now I’ve had a new idea. The trouble with the ploughing through debris theory [John B Murray 2006] is that at orbital altitude there won’t be strings of ejecta narrow enough to make those regular grooves, it has to involve some fine ring material. But if Phobos was ever orbiting in a ring it would have the same velocity as the ring material in which it orbits, it wouldn't have ploughed through anything. So here’s the new idea. If, during the period when Mars had these putative rings, Phobos had a more elliptical orbit, but in the same plane as the rings, it would have come screaming in and ploughed right through the rings at periapsis on each orbit. To create the grooves, Phobos would have had to be tidally locked as it is now, to present the same face to the flak, though it must have wobbled a bit, going by the angles of the grooves. (cf. Murray)
Perhaps the rings even formed in the same event that created Phobos, whether impact or capture, presuming there was enough material dislodged by the tidal disruption if it was the latter.
I understand that the orbits of smaller particles and dust circularise and flatten out relatively quickly by collisions, while a large chunk like Phobos, would slowly circularise by tidal forces, so if they formed together there would be a time when the orbits were different. Another point is that a common source for Phobos and the rings would be most likely to put them in the same plane.
The involvement of rings of fine material is crucial. How else could a groove form that extends the length of the flank in serene uniformity, than by collison with a narrow linear obstacle like a ring edge on? There are some less well defined grooves that are clearly crater chains, like the five little craters almost identical in size, equally spaced in a line parallel to one of the huge smooth trenches. These could have been caused by irregularities in the rings, bits where larger and fewer ring particles accumulate.
Obviously the rings didn't persist for long, they aren't there now, and Phobos must have disrupted their structure by it's regular visits. But they lasted long enough to leave the grooves.
Does it have any merit?
Would there even be any evidence on the Martian surface of rings? They'd have to be large enough to make it to the surface, and if the atmosphere was thicker in those days than there'd be no way of knowing.
We'll get new photos in a couple days anyway though.
i just tossed out the idea as a late night idea . I was thinking of my bad brakes and in the past they have ground the disks and drums .
seeing as Phobos is just a ball of rubble ( like a chocolate chip cookie - with almonds)
the stresses from Apogee/Perigee ( .3 Km) small but add in meteor hits ( Stickney) and it is not a surprise that there are there .
I'm pleased to see new discussions of the formation of these unusual grooves. The ring hypothesis is unique, as far as I know. My concern would be that it would have to account for grooves in multiple orientations, including north-south oriented groove sets crossing the north pole from 90 to 270 longitude.
Also, don't forget there are grooves on Gaspra, Ida and Eros... they are not as numerous or organized as those on Phobos, but they still exist. Do we need separate explanations for grooves on different bodies, or can one be found that works for all of them?
Phil
I am just starting a new photomosaic map of Phobos, using the best modern images. Positional control will be from the Viking mosaic made by Damon Simonelli, Peter Thomas et al. at Cornell in the 1990s, but this will be 3x the resolution and using much better images. I'll post sections of it as they are completed, in a new thread. Maybe it will help the groove origin discussion, though I'm doing it for other reasons.
Phil Stooke
hi phil i found that the new isis shape model of Phobos i did was of not much use on the "low" res images
but if you want it let me know
I would like to elaborate a little on my "ring-whacker" hypothesis (thanks Shaka for the monicker).
Although the grooves generally extend from the leading face along the flanks of Phobos, they are not all parallel. They vary widely near the apex, they even cross eachother. But along the flanks they are nearly parallel as far as I can see, varying by ten degrees or so at most.
The explanation could be that as Phobos slammed into the rings on each pass, it altered the distribution of mass in the main body, changed its shape a bit. Being tidally locked, its orientation would have to change to accommodate the new shape, and on the subsequent pass it would be travelling in the new orientation, presenting a slightly different face to the flak. The shape seems to have been constant enough to keep the same hemisphere in the direction of travel, all the grooves peter out as they approach the trailing hemisphere, but that's about all you can say. Near the leading apex they are confused, with some grooves cutting others. (This presents an ex-archaeologist like me with an interesting example of stratigraphy, the groove that does the cutting must be later than the one cut.)
But the compelling evidence for this hypothesis is the morphology of the grooves. The best of them are smooth trenches a hundred meters wide and twenty kilometers long, straight as a Roman road, impervious to the terrain traversed, crossing crater walls even into the hollow of Stickney. How could such a feature arise? A ring would do it. A flat thin ring, met edge on. It would be like slicing the top off your boiled egg with a knife, only this knife didn't penetrate. The one good example of rings we have in the Solar System is Saturn's glory. I have read that they are of the order of ten meters thick. That sounds about right for a hundred meter wide trench. If Mars' putative rings were similar to Saturn's, they would have been ideal for trench-gouging.
Phobos' orbital velocity is currently about 2Km per second. If we consider that during the time of its elliptical orbit, its orbital velocity at periapsis was double that, while the ring particles were orbiting at it's current velocity, the delta v was about the same, 2Km per second. The impact of millions of tiny particles, in a ten meter thick layer, at 2Km/s would create just such a trench. The escape velocity of current day Phobos is less than 12m/s. Much of the ejecta from the impacts must have departed the scene, but there may also have been accretion. Either way, the distribution of mass would have been altered.
Some of the grooves are obviously crater chains, where the impactors were much larger than particles of dust. These are in much the same orientation as the long smooth grooves. I read that the particle size in Saturn's rings varies from ring to ring, and that some like the Anthe Ring Arc are limited in extent. During the formation of Mars' putative rings there may have been similar variation and irregularity, particularly with the disruption by Phobos. The larger pieces of debris from the formation event had to go somewhere. Maybe there is a mechanism in the formation of rings from a debris cloud that sorts out the particles by size. If so, the nice regular chains of similar sized craters at similar spacing could be the result of collision with such a size-sorted ring or arc. (I'm afraid I'll have to go and read some more about the theory of ring formation.)
That's all I can think of now.
I don't think the reorientation idea would stand up to a dynamical analysis, but it's ingenious and worth studying. A couple of other things to think about... would the process dig grooves or build ridges? (i.e. is the impact velocity large enough to do what you want?) And what about topographic shadowing? At the edge of the disk the particles would hit the forward-facing surfaces on ridges or crater walls, but not the leeward sides of them. Can we find examples like that?
Phil
No telling what we might find in a new high-resolution photomosaic map of Phobos!
Phil, I don't think I see any examples of topographic shadowing. It's something I hadn't thought about.
On refelction I have to concede that the shape-shifting idea is a bit lame. It doesn't look as though much matter was lost or accreted by the groove formation, at least not a significant proportion of the mass of the main body. If you filled the ridges alongside the grooves into the hollows it looks like it would restore the ungrooved surface. Not enough to change the centre of gravity significantly.
But collision with a ring could affect its orbit. Remember that this hypothesis rests on the idea that the orbit of the main body and the rings were co-planar. That in itself is a big ask, and maybe it is answered by a common original impact. Even so, co-planar is not that well-defined in a rubble cloud trying to settle down into rings. Phobos' orbit could have been perturbed sufficiently on each pass at periapsis to nudge the next pass a few kilometers higher or lower, the sort of separation we see between the grooves. Like aerobraking, if you get the angle just a bit wrong, it send the craft off-course.
If Phobos ploughed through the rings with its equator above or below the plane, making grooves in the middle latitudes, the path of the grooves should trace the intersection of the ring-plane and the surface, they should follow a contour. I have been trying to verify this using the folded paper model of Phobos published on this site some time back, but the angular shape is too crude, and anyway I couldn't figure out how to glue those last seams. A high-res digital 3D model would be really helpful. But if it proves true that the rings trace out the contour of a plane intersecting the surface, it would clinch the ring-whacker theory in my opinion. What else could Phobos hit that's flat and a few meters thick?
The other problem is the criss-cross pattern of grooves on the leading apex. It seems that the orientation about the direction of travel varied between passes, as if Phobos was oscillating about the gravitational minimum, mainly in latitude. We see something like that in the libration of the Moon, it wobbles in its orbit. The angles of intersection of the grooves means Phobos must have wobbled quite a bit, around 90 degrees. Perhaps the wobble was amplified by off-centre passes.
Does anybody know where to find a high-res digital 3D model?
JohnVV has provided us with this spectacular model for Celestia.
http://celestiamotherlode.net/catalog/show_addon_details.php?addon_id=1359
Extremely interesting idea, bk_2! Even I can grasp it and visualise it without understanding orbital dynamics. Therefore I think it's elegant, minimal, and retrospectively obvious - all attractive properties. (Then again, I have a notorious tin ear... ) A few questions that occurred to me reading the very interesting discussion:
1. What would a ring/moon impact look like? I suspect it shouldn't be pictured as a series of point-events - multiple distinct impacts, releasing a burst of energy and creating a crater. Instead there'd be a continuous rain of impacting particles at any given point. (A curtain of dust raining down in a ruler-straight line... what an image!) How would the end-result of lots of small impacts in one spot compare to one big one, assuming the same (cough) aggregate mass for the particles as for the monolithic impactor? Does the outgoing ejecta interact with the incoming ring material?
2. How do the masses of the moons where groove-like structures have been observed compare to those of moons without grooves? Larger objects might have more energetic internal processes renewing the surface, or perhaps there's an upper bound to the gravity of moon. (Wouldn't stronger gravity fields mean the ring particle orbits would be rapidly disrupted?) I'm thinking of the wake images of the Saturnian shepherd moons and trying to visualise the dynamics with a larger shepherd, but I'm handicapped by ignorance of the calculus; and ISTR that these phenomena can be startlingly unintuitive!)
3. [EDIT: remove some of the foolishness.]
4. With respect to the crossing / intersecting angles of the grooves (and come to think of it, parallel grooves are presumably a special case of the general phenomena: something about the relative motion of ring and moon must have changed for the track to have moved across the moon's surface):
- perhaps the groove-creation isn't continuous. Perhaps it was only one orbit of the moon in 100,000 intersects the ring. Or 1000 consecutive orbits, but with each episode happening only every 10^2, 10^3, 10^4 years.
6. Perhaps the groove-creation happened before Phobos was tidally locked?
7. Why are the grooves discrete structures, rather than very broad bands? If the moon/ring aspect angle was changing, presumably it would happen at a steady state. If every orbit the moon makes intersects with the ring, whilst it's rotational axis is slowly precessing (or it continuous slowly rotating prior to being tidally locked), that would make the impact zones broad strips, or the shape of two very thin triangles touching at the apex. Instead, we see distinct grooves of similar widths, separated by apparently virgin surface typical of any common or garden rubble-and-dust-pile. To me this suggests that either:
i. whatever changes the location of the ring's intersection with the mooon was a sporadic, short-duration event; or,
ii. that the actual ring/moon intersection that caused the rings
8. As I understand it, Saturn's rings are largely fine dust and ice grains - 10^-3cm -- 10^2 cm or thereabouts. The masses of particles in rings resulting from impacts on Mars, or from tidal disruption of passing rubble piles, might be expected to have a different mass distribution curve.
9-99: ..?
Hungry4info but that cmod of phobos ( i have other formats) is a sculpted model .
done by hand and not made with 3d stereo ( or lidar) data
this is the same argument i have with t00fri
I am artistic and he is 100% scientific
@imipak
I told that to my five-year-old grandaughter, "elegant, minimal, and retrospectively obvious". She laughed like a drain.
But to the matter.
> 1. What would a ring/moon impact look like?
Dusty, I expect, ejecta from the buzz-saw of the ring would have obscured the view. Would it have interfered with the incoming ring? It depends on the trajectory of the ejecta. If you drop a pole flat in the pool, the splash it makes is a sheet on either side, angled away from the direction of impact. I expect the impact of the thin, colimated ring would do something similar, most of the ejecta would get clean away, from the incoming ring and the feeble gravity, and return to the rubble cloud.
> 4. ... Perhaps it was only one orbit of the moon in 100,000 intersects the ring
If the rock of this idea is sound, the grooves formed in the early period when the orbits of the main body and the rings were different, but co-planar. I think the series of grooves were lain down in short order, relatively speaking, before the rings were totally dispersed by the repeated passes. So I think the intersects would have been on each pass.
> 6. Perhaps the groove-creation happened before Phobos was tidally locked?
What we are discussing is the grooves that we can see on the current surface. There have been no significant changes in the shape of the moon since they were laid down, no scarps or groove discontinuities. So the c.o.g. hasn't changed much since the grooves were laid down. It had to be tidally locked in its current shape to present the same leading hemisphere. My point is that the tidal lock equilibrium could have been disturbed by an intersection. If the ring hit in the northern middle latitudes I can imagine it would rock it back on its heels, and set it rocking about the balance point.
> 7. Why are the grooves discrete structures, rather than very broad bands?
Yes, that's tricky. It depends on the angular velocity of the moon around the axis of its direction of travel at the time of intersection. How quickly did it wobble, or nod up and down around the balance point? That would depend on how close the c.o.g. was to the geometric centre, how unbalanced it was, and the inertia of the gross mass. I have to propose, without any visible means of support, that the nod was slow enough that the impact of each individual ring was not smeared out by the shifting terrain. But maybe the ring system consisted of many narrow rings, and intersection with each was brief enough to leave a narrow groove even though the moon was nodding.
> 8. As I understand it, Saturn's rings are largely fine dust and ice grains - 10^-3cm -- 10^2 cm or thereabouts.
Sure, but Saturn's rings are mainly ice and have a different origin. I don't know what it was, but it definitely wasn't an impact on the planet below. An impact on Mars would have thrown up a lot of rock, in chuncks of various size. They might have all been pulverized to dust but it seems unlikely. I suspect the proto-groove, the crater chains, are attributable to the remnant rocks.
There, some of them answered.
I hear hints that the Phobos images will be released on the 15th.
Phil
All right, then we're going to have to divide forces. Which of us UMSFers is going to go after the Phobos pics, and which are going to dive into the deep end of the LRO PDS release?
(*raising my hand for Phobos*)
I'll be at a meeting but it might give me a chance to do some light processing on the netbook with Gimp
My vote is for Phobos, since I doubt I could do much with the LRO images from that machine...
seeing as i already have a working folder for phobos and mro isis files
I would also need to install the lro isis files
And these things are BIG
http://www.esa.int/SPECIALS/Mars_Express/SEMK17CKP6G_0.html
Phil
With the latest spice kernels for Mars Express I just simulated the Phobos flybys with Celestia, am I right that the Phobos-Mars Express geometry is almost the same for every flyby?
The flyby distances were pretty accurate.
The ESA page says "Its origin is debated. It appears to share many surface characteristics with the class of ‘carbonaceous C-type’ asteroids, which suggests it might have been captured from this population. However, it is difficult to explain either the capture mechanism or the subsequent evolution of the orbit into the equatorial plane of Mars."
If it was a capture of a carbonaceous asteroid, possibly involving another body which was ejected in the process (which makes the capture hypothesis more plausible) could it not have shed a lot of matter by tidal disruption in passes below the Roche limit? The debris could have formed rings co-planar with the initially elliptical orbit of the main body.
If it was an impact, the impactor could have been a carbonaceous asteroid.
Although the ring-whacker idea has nothing to say about the evolution of Phobos' equatorial orbit, it must have been a factor in it's circularisation. Aerobreaking has been mentioned as a possible contributor. Ringbreaking would have been more effective than aerobreaking at transferring momentum, and would have occurred at a greater distance from the planet.
I wish there were a few more images on ESA page.
The lumpy appearance of the lineations on Phobos remind me of the boulder trails inside Victoria crater. Could this be a possible explanation? Are they lined up in the right direction? I note that Phobos is inside the Roche limit for a strength-less object so the boulder would be lost due to tidal forces once they reached the inner or outer parts of Phobos, relative to Mars.
Phobos grooves origin was an old thinking issue for me. I never believed about the explanation of being the result of crater ejecta sent to space from Mars impacts, because it would probably formed craters in Phobos rather than grooves.
I think Phobos is a captured asteroid. I know that a capturing mechanism is hard to explain unless an orbital energy loss of the captured asteroid should be introduced. Something like ours probes, which their retrorockets have to be operated in order to loss orbital energy to be captured by Mars instead of making a fly-by.
Phobos, as a prior free asteroid, had its own rotation. Now Phobos is tidally locked, so its rotation rate is equal to is orbital angular speed. Any moon tidally locked to its planet has some very know properties (Cassini laws):
- Its principal axis of inertia with minimal inertia is pointing directly to the center of mass of its mother planet.
- Other principal inertial axis is perpendicular to its orbital plane.
- The last principal inertial axis is orthogonal to the other two axes (in the direction of its velocity along the orbit).
There must be a time in which Phobos should have experienced tidal torques because of the non-alignment of its principal axis of inertia in the above mentioned way and because of its previous freely rotation rate before been captured were different from the tidally locked one. All this resulted in tidal torques applied to Phobos trying to force it to orientate its principal axis of inertia. This process generated internal energy inside Phobos and, also, differential tidal stresses in its ground and its interior.
The energy released in this process is the one that captured Phobos, circularized its orbit and tidally locked Phobos to Mars (and perhaps emanated volatiles along the grooves, forming what appear chains of craters).
At some point, as its rotation rate was decreasing, it should have experience a period of alternative torques (like a pendulum). All these effects generated dynamical differential tidal torques all along the moon (these stresses can be calculated, and I will do it when I´ll have enough spare time) which maybe can be the origin of the grooves. If the calculation of this mechanism predicts shear stresses in Phobos which alignments are consistent which the parallel pattern of the grooves, it will be a good theory for the origin of the grooves.
If this is a plausible mechanism, I guess it can explain some grooves evidences we see:
1. Why grooves are parallel and with origin in the closest point to Mars?, because are the lines of higher shear stress when Phobos was still in the process of been tidally locked to Mars. They converge in the point of the principal axis of inertia, which is the closes point to Mars, close to a point of the summit wall of Stickney crater.
2. Why are different families of grooves with small angle between them?, because Phobos could have had a small variation in internal density (is very porous) or because an impact, that change a little the orientation of its principal inertial axis.
3. Why Phobos has grooves crossing in almost right angle?, because in the past the principal inertial axis could be one orthogonal to the real now.
4. Why grooves cross almost all of the craters?, because craters were formed in Phobos when it was a free asteroid and grooves were formed later, in the process of beeing captured by Mars.
This is only a theory of mine (maybe I can be totally wrong), that I worked out a little, but still not enough to have minimal results.
Thanks. Hope explanation is easily understood.
The Mars Express blog has a post about the grooves of Phobos and their possible origin: http://webservices.esa.int/blog/blog/7. At the bottom of the post, there is a link to an article on the subject.
Here's a cross-eyed stereo version of the red-blue anaglyph released by ESA:
Looking at the images cross-eyed produces inverted relief. You need to swap the images for correct cross-eyed viewing.
Thanks for the heads-up charbobob! I've adjusted the image and replaced the incorrect version in my previous post.
ESA's Planetary Science Archive (PSA) - Mars Express new batch (2010-06-01). Orbits 7105-7697.
Nothing particularly exciting except Phobos and Deimos mutual event.
Phobos thirty-eight years later. I'm not sure why the image taken by Mariner was published with a strange characteristic texture. I love this picture, it was with me all my life.
H6916_0000_S12
Q: Phobos is tidally locked; as Mars' North pole and rotation shift over the course of millenia, so will Phobos' orbit?
A: No.
Tidal lock has driven the rotation axis to be parallel to the orbital axis (and Phobos' long axis to point to Mars). This is irrespective of Mars' rotation axis orientation. Tidal locks will force obliquity to either 0 (north pole "up") or π (north pole "down").
Edit: Another thing of note: If Mars' obliquity caused meaningful changes to the inclination of the orbits of Phobos, Deimos, then it would be no mystery as far as their origins are concerned as to why their orbits are coplanar.
The rotation axis of Mars precesses and varies in obliquity. So is it a remarkable coincidence that Phobos and Deimos orbit in very close to equatorial orbits, or are their orbit planes tied to the planet's equatorial plane? That seems to be what brellis is asking, rather than a question about the rotation axis of the satellite. Alas, I know nothing about orbital dynamics.
Phil
FURTHER ORBITAL MECHANICS DISCUSSION MOVEDhttp://www.unmannedspaceflight.com/index.php?showtopic=6771&st=45 - ADMIN
Orbits 7701-8312 released. (ftp://psa.esac.esa.int/pub/mirror/MARS-EXPRESS/HRSC)
Phobos over Mars, the view more beautiful than before. The image is sharp as a razor.
The most beautiful image sequence of passage of Phobos over Mars
Orbit 7982
Bra-VO, ESA!!! Absolutely gorgeous!
Very spectacular!
Phil
Like we're floating alongside.... hurry up Phobos-Grunt!
Wow. That is nice!
What causes the wavy appearance of the Martian limb?
A slight rocking of the spacecraft during the scan. If it had just rotated to take this off-nadir view the long booms might not have settled down yet.
Phil
Ahhhh...yeah, makes sense; I thought it was some sort of processing artifact.
Strange stone, alien vapor . . . .
Fran Lebowitz
Wow!
That Gusev picture is fabulous.
MEx wide-angle images have always impressed me, but, boy, this set is exceptional! Well-spotted, Stu.
Thanks very much Stu for bringing that Gusev image to the fore... it's a belter!
Any idea of the date the Phobos pictures were taken? I know I could check myself, but I am traveling and accessing this through my mobile, so if someone could dig this info for me...
A couple photos (one rendered in 3D) have been released from the Phobos fly-by of 09 Jan 2011. They are on the ESA Mars Express blog, at
http://webservices.esa.int/blog/blog/7
The planned landing sites for Phobos-Grunt are shown.
Not many images, but very nice ones.
They are very nice, and they also provide useful illustrations for the differences between HRSC and SRC and also how the way HRSC gets its simultaneous stereo. I would love to see one of our morph magicians produce a tweened animation of the 5-image view of Phobos near the bottom!
I'm not yet one of the magicians but I have been fascinated by the application of morphing with images like these, so here's my effort . . .
EDIT:
revised AVI and gif
ElkGD, that is pretty darn good! thanks!
Finally, it's finished.
Phobos animation from five Mars Express images taken by HRSC camera.
Original images copyright: ESA/DLR/FU Berlin (G.Neukum).
http://www.youtube.com/watch?v=CCvEREEdBck
Gorgeous, Machi. Thank you.
Thanks!
I just added two avi versions of Phobos animation.
Full resolution http://planets.wz.cz/mars/marsorig/phb_mex_dam_001.avi (this is in fact full original resolution, youtube version is reduced to 1920×1080) and reduced resolution http://planets.wz.cz/mars/marsorig/phb_mex_dam_001b.avi.
Drool...
I notice that Emily's 5 image montage here http://www.planetary.org/image/image5-492-20110120-8974-sequence-05-PhobosFlyby.jpg can be viewed cross-eyed to yield four 3D versions. Presumably a 3D movie experience could be achieved by viewing two side by side copies of Machi's excellent movie with a small time offset.
I haven't software for this, but whole 3D animation (little shorter) is possible. Something like Luca Cassioli made from animation of comet Hartley.
... and here are some new ones showing Phobos AND Jupiter !!! Enjoy...
Phobos & Jupiter in Conjunction
Sorry if this was covered somewhere else, but I didn't see it mentioned here. A couple weeks ago, ESA published a new Phobos fly-by video.
You can see it at:
http://www.esa.int/esaSC/SEMHGWD1XOG_index_0.html
It shows Phobos in conjunction with Jupiter. Includes a Phobos image in 3D.
there isn't a thread for Deimos, so I will post here this interesting paper just published (free of charge if registered):
http://www.aanda.org/index.php?option=com_article&access=doi&doi=10.1051/0004-6361/201118603&Itemid=129
The official ESA web release about the improved Deimos orbit determination done by MEX is http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=50842.
The Astronomy and Astrophysics paper on the Deimos measurements is http://www.aanda.org/articles/aa/pdf/2012/09/aa18603-11.pdf.
naif update
ftp://naif.jpl.nasa.gov/pub/naif/generic_kernels/spk/satellites/mar097-vs-mar085_deimos.txt
ftp://naif.jpl.nasa.gov/pub/naif/generic_kernels/spk/satellites/mar097-vs-mar085_phobos.txt
mar097.bsp
first image from the 22 December flyby
http://blogs.esa.int/mex/2013/12/24/merry-christmas-from-mars-express/
Worth noting that that entry on the ESA Mars Express blog actually refers back to UMSF.
From Daniel Scuka's blog entry: "Looking for a challenge? Let us know where on Phobos you think this image is located (there's a cool 'map' of Phobos over at http://www.unmannedspaceflight.com/index.php?act=attach&type=post&id=21565)."
Daniel Scuka is Senior Editor for Spacecraft Operations at ESOC, ESA's European Space Operations Centre, Darmstadt, Germany.
Phobos animation using a shape model...
http://spaceinvideos.esa.int/Videos/2013/12/Phobos_360
the "phobos_ver512q.tab" mesh from
VO1_SA_VISA_VISB_5_PHOBOSSHAPE_V1_0.zip
from the pds small bodies node
displays in Blender
http://imgbox.com/aciiErGZ
it basically is a .obj mesh
As is mentioned in an ESA https://www.esa.int/Enabling_Support/Operations/A_close_encounter_with_a_mysterious_moon about the recent close flyby of Phobos by Mars Express, "[t]he orbit of Mars Express has been fine-tuned to get us as close to Phobos as possible during a handful of flybys between 2023 and 2025". A quick http://spice.esac.esa.int/webgeocalc/#NewCalculation search gives five flyby opportunities with a distance to the surface of less than 100 km during this period:
Date ............ Distance to surface [km]
2023-07-21 ... 52
2024-01-09 ... 55
2024-05-30 ... 62
2024-11-15 ... 45 2025-09-16 ... 40
2026-07-21 ... 66
2026-12-07 ... 80
So mark your calendar and let's hope Mars Express isn't http://www.unmannedspaceflight.com/index.php?s=&showtopic=1463&view=findpost&p=258827 by then.
EDIT: Close flyby in 2025 has disappeared. Predictions for 2026 are added.
Looking forward to those close flybys. I'm especially wanting images from close flybys of the blue-white toned and the ochre toned areas on Phobos. As well as another, closer pass with the MARSIS instrument.
https://www.esa.int/ESA_Multimedia/Images/2022/10/Mars_Express_peers_beneath_the_surface_of_Phobos
Mars Express certainly needs to continue. MMX's planners would certainly be grateful for more data.
Since Exomars is being delayed for so long, there's surely a small amount of money in the ESA budget, right? Extended missions are generally much cheaper to run than a primary mission, with the smaller teams and efficiency/experience of those still working on it.
In the long term yes, but that would all be spread out over the next 8-10 years. Since these Phobos flybys are in the next 2 years, the costs of the primary Exomars mission would be being spent right now if not for the delay.
The peak cost is the period before and during a primary mission, from what I read in NASA budgets (https://www.planetary.org/space-policy/planetary-exploration-budget-datasetwhich show a sort of bell curve and ahttps://docs.google.com/spreadsheets/d/12frTU01gfT1CXGWFimN3whf4348F_r3XolTqBt02OyM/edit#gid=1130871780). I'm assuming the logic works the same with ESA missions.
Sorry to get a bit into the weeds on this, but there should be no excused to cancel scientifically significant flybys of a very interesting object!
Funny how http://www.unmannedspaceflight.com/index.php?s=&showtopic=480&view=findpost&p=258983 (When you're having fun)
On Friday 21 July at around 05:04:47 UTC, Mars Express (MEX) will make a close flyby of Phobos at a distance to the surface of just 48.4 km, according to the latest https://www.cosmos.esa.int/web/spice/spice-for-mex (SKD), via http://spice.esac.esa.int/webgeocalc/ (WGC).
My clumsy freehand overlay of a WGC-generated Nadir Ground-track plot on a colour-coded https://europlanet.dlr.de/Mars/phobos_index.html of Phobos seems to be in good agreement with the corresponding http://www.unmannedspaceflight.com/index.php?act=attach&type=post&id=53520. The blue arrow shows the flight direction, the two concentric circles mark the point of closest approach to the surface, the small dots on the plot are one second apart, and the length of the plot between start at 05:03:42.465 and end at around 05:05:54.924 UTC is the time period when the distance between MEX and the centre of Phobos is less than 200 km.
While we are still patiently waiting for information about the implementation of the last Phobos flyby of Mars Express, the next flyby, in a http://www.unmannedspaceflight.com/index.php?s=&showtopic=480&view=findpost&p=258983, is due to take place at around 02:17:05 UTC on Tuesday, 9 January; passing within 55 km of the surface at closest approach.
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