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Posted by: Stu Mar 29 2008, 12:54 AM

Can't wait to see these...!

http://hirise.lpl.arizona.edu/HiBlog/?p=166

Posted by: PhilCo126 Mar 29 2008, 08:45 AM

These processed images of the largest and innermost Martian Moon Phobos (Pavor) should become available after April 1st

Posted by: tedstryk Mar 29 2008, 03:18 PM

I could swear I remember they planned to image Deimos a while back. Did anything ever come of that?

Ted

Posted by: Stu Apr 9 2008, 03:35 PM

Phobos images http://www.nasa.gov/mission_pages/MRO/multimedia/20080409.htmlfor everyone to drool over... !!!

(Maybe someone can change the subheading of this thread to "images available NOW"..?)

Posted by: Stu Apr 9 2008, 03:52 PM

Here's a tweaked crop of the bright area on the edge of Stickney...

Swear box time I think guys...

Posted by: ugordan Apr 9 2008, 04:03 PM

Whoa!!!!

Posted by: Dominik Apr 9 2008, 04:11 PM

Impressive Images ... I hope, that there'll be a new map for Celestia in the near future.

Posted by: Stu Apr 9 2008, 04:17 PM

The edge of this canyon has GOT to be on the list of Places To Visit when people reach Phobos...

Posted by: ustrax Apr 9 2008, 04:27 PM

Posted by: elakdawalla Apr 9 2008, 04:33 PM

There are more versions of the images, including a beautifully http://photojournal.jpl.nasa.gov/catalog/PIA10368, at http://photojournal.jpl.nasa.gov/target/Phobos.

Oh, and I should add: Wow!

--Emily

Posted by: Stu Apr 9 2008, 04:40 PM

Gorgeous, just gorgeous.... !

BTW, congrats on your "Excellent" rating on the http://www.blogged.com/directory/education/science/2site Emily! Well deserved

Posted by: Stu Apr 9 2008, 04:58 PM

I just broke my ********* swear box...

http://hirise.lpl.arizona.edu/images/2008/details/phobos/PSP_007769_9010_IRB_StickneyU.jpg

Posted by: tedstryk Apr 9 2008, 05:05 PM

Those images are absolutely incredible. WOW!!!!

Posted by: Ant103 Apr 9 2008, 05:55 PM

Impressive and just incredible
Gargle! It's a gorgeous pic!

Posted by: volcanopele Apr 9 2008, 06:29 PM

Wow, that's awesome!!!

I presume the reddish color is from contamination from Mars?

Posted by: infocat13 Apr 9 2008, 06:46 PM

Perhaps the red color is from solar radiation interacting with carbon and water in the surface material

Posted by: SpaceListener Apr 9 2008, 07:51 PM

Nice shape, context and color Phobos!

Its picture, around the rim of Stickney's crater is bright since this surface is fresher, and therefore younger, than other parts of Phobos. http://www.nasa.gov/images/content/221821main_PIA10369-516.jpg

I am copying an article:

Where would most probably be located the ice water on Phobos?

Posted by: tedstryk Apr 9 2008, 08:34 PM

The color is so enhanced that one would have to know more about the images to begin to guess at whether the reddish color is Mars-derived. Based on my experience working with Phobos-2 data, Phobos is basically gray, so these images have got to be really stretched. By the way, wasn't it going to image Deimos soon after arrival?
Ted

Posted by: nprev Apr 9 2008, 11:05 PM

Nice to come home to...<clink!><clink!><clink!>...just beautiful, is all!!!

I sort of remember the Deimos idea as well, Ted; would love to see them, if they ever get to it!

Posted by: tedstryk Apr 10 2008, 12:43 AM

We have come along way since Mariner 7

Posted by: nprev Apr 10 2008, 02:01 AM

Indeed! IIRC, that is the shadow of Phobos in the upper right-of-center area, yes?

Posted by: tedstryk Apr 10 2008, 02:13 AM

No, that is Phobos.

Posted by: tuvas Apr 10 2008, 03:58 AM

I remember in the early days of HiRISE, it attempted to imaged one of the moons, but the pointing was slightly off, so HiRISE didn't quite get the image. I don't know what the issue was, but sufficeth to say that the whole MRO team has considerably improved knowledge of the system since that time.

These images of anything other than Mars require an extraordinary amount of work, and at least in the days that I worked with the team, the targetting specialists on HiRISE worked for about 60 hours a week for 6 weeks just to get 2 weeks worth of HiRISE images on Mars. The special images, moons, stars, Earth, Jupiter, etc, took several days I believe just for the one image, as the software wasn't really set up for those kinds of things.

Still, I must say, it is quite the image. Wierd to think that HiRISE can get the entire moon in one shot. Good work guys!

Posted by: JRehling Apr 10 2008, 05:43 AM

My calendar doesn't say there's an extra Christmas in April this year. Woah! This is better than a lot of flybys that I spend months looking forward to!

All of a sudden it occurs to me that the atmospheric pressure of Phobos (ie, zero) isn't THAT different from that of Mars. This could be a lot more similar to Mars than I'd ever spent 5 seconds thinking about.

Posted by: edstrick Apr 10 2008, 09:53 AM

"No, that is Phobos. "
<grins at tedstryk> I have a smurdgy xerox of the article in <i think> Icarus, identifying it in that pic and presenting the little matrix of pixels.

The new pic: "Gosh! Wow!! Boy-Oh-Boh!!!"

I remember watching evening news, probably CBS with Uncle Walter Crankcase <grins> in my college dorm when the first blurry small Mariner 9 press-release pic of Phobos showed up on screen and I ***KNEW*** what it ***HAD TO BE*** before the announcer got the words out. later Mariner 9 pics were considerably better and one or two pretty detailed. But the first one was able to clearly show cratering of different sizes, and I thought "Diseased potato".

My impression is that space-weathering is NOT reddening the materials in the scene, almost entirely darkening them without changing color much. In the color coordinates of the image, bright material on crater rims, knobs, and rounded upper "edges" of things (convex-up surfaces) that can be expected to shed loose debris preferentially down-slope are bright, but typically the same color as surrounding material.

In the extra-enhanced Planetary Soc Blog copy of the image, re-oriented with Stickney and the far limb beyond the crater at left, the blue-white and blue-gray area on the near rim of Stickney has cinnamon reddish patches seemingly embedded in it, one exposed by the crater on the outer slope of the Stickney rim, with red streaks trailing down-slope from topographic high of the rim.

A quite small sharp crater on the rim of Stickney toward the limb at 9:00 clock angle <in this orientation> has a mix of both red and gray-white in clearly defined radial crater rays extending out about 1 small crater diameter. Clearly both materials present where the crater struck.

A smallish crater, rater eroded, on the rim of Stickey at 12:00 clock angle is surrounded by an area of very uniform purplish gray color, medium and dark, NO REALLY BRIGHT PATCHES AT ALL. Some of the purple gray extends out of Stickney. but it also extends into the crater, partway down the crater slope.

Medium reddish brown material seems to form a discrete band at the topographic break between the slope and floor of Stickney. Darker material above it is brown and in one area quite dark magenta-brown, not obviously related to the purple gray crater on the rim of Stickney, but possible related to a very dark band of material extending down the crater wall from an unusual dark spot on the rim at about 11:30 clock angle.

Much of the floor of Stickney is dark, lighter in and around small craters and on knobs. Colors of knobs generally, but NOT always, relate to colors of surrounding material, which varies across the floor of Stickney in no well defined pattern, though the largest patch of gray and blue-gray is connected to the blue-gray on the near rim of Stickney. Smaller, lower contrast color patterns are rather jumbled.

The impression is of an "assembled" body, or one which might once have had well defined structure but was broken and re-assembled. It looks somewhat like a rubble pile, but is heterogeneous on very large scales, with smaller blocks of different material now within large areas of a different material.

Wow.

Clearly, Phobos sampling will get a variety of materials, probably more than one unweathered component, once knobs and boulders are targeted. Clearly, samples from different areas will be needed to understand Phobos's variety.

On to Deimos! <even at lower resolution, the shear colorimetric discrimination shown here will almost have to show something interesting.>

Posted by: Bill Harris Apr 10 2008, 01:14 PM

Very good discussion, Ed.

My "first impression" is that Phobos is dusted with the ubiquitous limonitic Mars dust, and the bluish area looks as though a big puff of gas came along and blew some of the dust off.

Knowing full well that the "Mars dust" is not limonitic, nor do we have puffs of gas roaming through space...

<clink, clink>

--Bill

Posted by: ElkGroveDan Apr 10 2008, 02:10 PM

It looks to me like perhaps a very large bird used the rim of Stickney as a perch.

Posted by: Stu Apr 10 2008, 02:27 PM

Maybe a Phoenix..? (ducks)

Posted by: Joffan Apr 10 2008, 02:55 PM

OK, which is it, phoenix or ducks? clearly a priority sample target!

Posted by: Bill Harris Apr 10 2008, 04:17 PM

IIRC, Stickney is about halfway between the leading hemisphere and the sub-Mars point, so that "minus-red" splatter may be much akin to a bug-splat on a windshield. With the "rotated" image, north is "up" and the leading edge is to the left side? IIRC.

--Bill

Posted by: elakdawalla Apr 10 2008, 04:48 PM

You're right that Stickney is about equidistant between the leading apex and the sub-Mars apex, but the splat trials to the sub-Mars side. Here's a version of the image, rotated so that north is upright. It's an almost perfectly equatorial view of the sub-Mars hemisphere (just a hair more to the north than equatorial). Remember, everybody, that nearly all Mars missions are in pretty low-altitude, circular orbits, much lower altitude than Phobos orbits, so they can see only as much of Phobos as we can see of our own Moon: the sub-Mars hemisphere. I've been debating starting to call this the "nearside" of Phobos to help bring home that point, but I'm not sure if that will be any less confusing than "sub-Mars hemisphere." Of the orbiters at Mars since Viking, only Mars Express has an elliptical orbit that allows it to see other parts of Phobos.

I actually like this version better, think I'll make it this way on the Society web pages...

--Emily

Posted by: edstrick Apr 10 2008, 06:05 PM

"I actually like this version better, think I'll make it this way on the Society web pages"

In that orientation, it matches our "expected illumination" orientation. Our brains are somewhat wired, at least by lifetime experience if not evolution, to expect illumination from "above". That's why faces lit from below are creepy-horrorshow feeling, in part.

A trick for viewing images where topography looks inverted and craters are bumps and valleys are ridges is to 1.) orient the image so the real illlumination comes from "above" in the viewer's orientation. Even physically matching real illumination (from a desk light or something) to the on-page (or on screen) illumination can sometimes help force the brain to counter-invert the image back to it's proper craters-are-craters perception.

Posted by: ElkGroveDan Apr 10 2008, 06:27 PM

If you have a desk lamp move it so that your ambient lighting is coming from the same direction as the light source in the image. Opening or closing curtains, or turning on or off ceiling lights often helps.

Posted by: marswiggle Apr 10 2008, 07:36 PM

This might help to counter any inverted topography. After some trial and error, I managed to produce, imo, an almost professional-looking crossed-eye stereo image of Phobos (reduced image quality though). I didn't get working anaglyphs perhaps due to light colour.

I first resized the nearer and bigger of the original HiRISE images, which is the left-eye (ie. right side) image, to 87 %, rotated the l/r images 108 and 112 degrees respectively, the resulting stereo pair shrunk to approximately 31 %. Extra white spaces filled with black.

It's rather an exaggerated stereo effect... beware eye strain!

Posted by: ngunn Apr 10 2008, 07:50 PM

Brilliant! I should have joined the original round of applause for the HIRISE team but didn't - what images!! - but seeing this I could no longer remain silent.

Now what's really wanted there is simultaneous 'zoomify' on the two images so you could roam the surface with moving crops of small areas. Then you could get the images the right distance apart for a non-exaggerated effect. I'm sure this could be illustrated with ordinary non-movable crops of, say, the near rim of Stickney. Maybe worth trying as you've already done all the work registering the images.

Posted by: tedstryk Apr 10 2008, 08:27 PM

Wouldn't "Mars-facing hemisphere" be clear enough?

Posted by: ElkGroveDan Apr 10 2008, 08:55 PM

Maybe Pink Floyd should record an album called The Dark Side of Phobos

Posted by: 4th rock from the sun Apr 10 2008, 10:30 PM

Here's a "real color" attempt at the Phobos image, using only the Red and Green-Blue channels and gamma adjustment.

Posted by: tedstryk Apr 10 2008, 11:54 PM

That is nice, although the color variations still seem a bit strong.

Posted by: Bill Harris Apr 11 2008, 01:13 AM

"Nearside" works. It is a very familiar concept with our own Moon, and is an economy of words. May not be as good with other tidally-locked moons, but for the Martian satellites and HiRISE it's about the only view we'll have.

--Bill

Posted by: jasedm Apr 11 2008, 09:05 AM

Fantastic images - well worth waiting for!!
From my 'wild theory' bag:
This view of phobos and the colouration makes it look ablated, with material having streamed back from the stickney area.
Could it be possible that Phobos dipped into a historically denser Mars atmosphere during capture of the moon (the general consensus I think is that the moons are asteroidal in origin)?
Has aerocapture been suggested as a possibility for the position of the little moon?

Edit: Have just read Emily's blog which has a section relating to Phobos' grooves - very informative, and a lot more convincing........

Posted by: marsbug Apr 11 2008, 11:17 AM

These images are great, and they've made me look at phobos as being more of a place in its own right, rather than 'one of the rocks orbiting mars'.

Posted by: ngunn Apr 11 2008, 12:14 PM

I can't shake off the visual imression that Phobos is a flying lump of wind-eroded sandstone with almost parallel 'beds' running right through it - even though I know that's nonsense!

Posted by: ilbasso Apr 11 2008, 01:01 PM

My first impression of the false-color close-up with Stickney on the image's right side, was the Planet Killer from Star Trek "The Doomsday Machine".

"It's got a maw that could swallow a dozen starships!"

Posted by: Phil Stooke Apr 11 2008, 03:28 PM

I have never been satisfied with the various explanations for grooves - they obviously don't radiate from Stickney, but Peter Thomas showed that years ago from 3D mapping in Viking images (Mars Express data not required for that interpretation). I think the Mars ejecta hypothesis is too contrived, though I might accept it for a small subset of crater-chain structures superimposed on the regular groove pattern.

I have argued elsewhere that the regular groove pattern is the surface expression of jointing in the interior, possibly produced by relaxation of compressive stresses when Phobos was impact-excavated out of a larger parent body. By this hypothesis, Deimos was from a shallower, less compressed part of its parent, if they are genetically related.

Nevertheless, the new pics are fab.

Phil

Posted by: Bill Harris Apr 12 2008, 12:10 AM

On the NASA/HiRISE website there is a map of the Phobos (Phobian??) lineations on (evidently) a cylindrical projection. Interesting relationship between the lineations and leading/trailing hemispheres.

phobos_map_grooves_lg.png

I'll bet that the origin of the lineations is post-capture or post tidal-lock.

--Bill

Posted by: marswiggle Apr 12 2008, 12:17 AM

Here goes. Full resolution x-eye image depicting the crater bottom and parts of the near/far rims.

I'm using StereoPhotoMaker for zooming and panning the images. It's really beyond my capabilities to do anything more than crop some samples with it.

Posted by: ElkGroveDan Apr 12 2008, 02:10 AM

Now, now, there'll be none of that on this site.

Posted by: Phil Stooke Apr 12 2008, 02:11 AM

You're no fun any more, EGD.

Phil

Posted by: edstrick Apr 12 2008, 07:11 AM

"... image depicting Stickney's bottom ..."

Asaph Hall's GHOST will haunt you for that!

Posted by: nprev Apr 12 2008, 01:40 PM

Ed, I can only call that a Phobic response...

I'm not even gonna comment on the fact that Marswiggle's excellent x-eye revealed a large pile on the bottom.

<puts on blindfold, lights cigarette, waits patiently for the machine gun to fire>

Posted by: edstrick Apr 13 2008, 08:31 AM

"... can only call that a Phobic response..."

(quietly inflates a balloon, steps to 1 foot from the blindfolded victim, and "needles" the balloon)

Posted by: Adonis Apr 13 2008, 09:37 AM

Hi everyone,

Images from MRO are fantastic. I'd like to share some especulations about some Phobos features.

The bright zone at the rim of Stickney coincide perfectly with the point in Phobos closer to Mars (or the central point as seen from Mars). At the same time, it's also the point with more tidal effect in Phobos or less gravity in the surface. I guess both facts (brightness and less gravity) should have some kind of relationship. Same happens with the opposite side, in which tidal effect is also maximized.

Because of tidal effect of Mars, close to this area gravity forces are not normal to the surface, but with a small inclination in direction to Mars, that is, some very small drag forces are in Phobos's surface in the direction to that bright zone. In the images I can see some dragged terrain or small attempts of avalanches in that direction (could it be this effect?).

In case of a big impact that shakes Phobos, the preference point to loose material into space should also be that point (could it be the reason for the bright zone?).

Grooves have also the direction and seems to converge to the maximal tidal effect zones. Because of the elongated aspect of Phobos, just before it got tidally locked to Mars there should have been a period in which it swung over the actual equilibrium point. In that period, those swings surely produced short time variations of drag forces in the surface due to tidal effects (could this be a reason for the grooves?).

Thanks