... and a new, rather gorgeous avalanche shot...

Click to view attachment

(cropped and colourised from ESP_016423_2640 )

Those are both exceptional images, Stu, thanks! Spirit's 'wings' are clearly resolved, amazing!

Looking like a frozen house fly stuck to a frosty window.

So this is what, the 3rd avalanche caught in the act? Are we sure MRO has no motion-sensor onboard? It sure seems that way!

The fact that MRO doesn't have any motion detection capability is testimony to the (apparently) astonishingly high rate of occurrence of these events.

Really interesting stuff happening here. Is the Cap being replenished anywhere near as rapidly as its edges are eroding?

You have a short memory.

In this thread a few weeks ago, it was revealed that there are avalanches in almost every MRO image during the 'avalanche season', and five avalanches from one image were shown.

Quote removed - Mod

Just about to go to bed, then I come across these new images. Can't sleep!
Very cool!

Crater near graben in Syria Mons: http://hirise.lpl.arizona.edu/ESP_016529_1350

Was the smooth stuff deposited before or after the ripples formed?

square crater(?). http://hirise.lpl.arizona.edu/ESP_016537_1425

Probably not a square crater, but an outcrop of folded stratified rock. There are several more U-shaped outcrops in the vicinity of this one.

"Baby" avalanche spotted on an image ( ESP_016449_2650 ) in the latest big image release...

Click to view attachment

Looks like the smooth stuff formed after the ripples. The smooth stuff resembles the material in the middle of the graben. (Note the presence of subdued craters in both units). This suggests that the smooth unit once covered a more extensive area and has been eroded away, exhuming an ancient rippled lanscape. This would mean that the ripples formed long ago and are most likely inactive today. Any other interpretations?
Tom

Oh wow!

http://www.universetoday.com/2010/05/10/la...y-impact-event/

Impact event thought to have caused an avalanche! Amazing picture, as usual!

Interesting, but I dunno if I buy it. Why isn't there the usual dark ejecta apron around the postulated recent crater? Also, there's something not quite right about the diffuse upper boundary of the streak; that also seems atypical.

Because it was covered by the dust from the avalanche? My 2c.

I agree with Eduardo. Nick you of all people should know about avalanches. If you are unlucky enough to trigger one, the material both above and below you moves down the hill. Moreover, in this case it was more like those mortar shells that the ski patrol use to clear slopes. The airburst triggers the movement milliseconds before the object's impact over a broader area, both up and down the slope (and left and right). And from these images, that's what it looks like to me.

I'll be interested to know how steep is the place. May be you know that on Earth, natural (snow) avalanches start at 30° and they may be are the most dangerous (since one wouldn't believe they can start with such a low angle).

The dust avalanche is now featured at the HiRISE website:
http://hirise.lpl.arizona.edu/ESP_017229_2110
The location is in the Olympus Mons aureole (Lycus Sulci) not the slopes of the volcano as the earlier article indicated. This is an area of rough, highly jumbled terrain thought to be formed from huge gravity-slide deposits shed from the lower slopes of Olympus Mons. This region is extremelt dusty and dust streaks are ubiqutous.
I couldn't determine the slope of the hillside on which the avalanche occured from MOLA elevation data. The area in the portion of the CTX image shown in the article is very small (only about 2 X 2 km) and below the useful resolution of the gridded MOLA dataset from the JMars program. Maybe someone knows a more sophisticated way to determine the slope. In any case I would guess that 30 degrees or more of slope is certainly possible.
Tom

Anyone else having trouble opening up images with the IAS Viewer?

never used it till now.
it is crashing on Arch Linux Firefox 3.6.3

Thanks, John. Anyone else?

Hi Stu

Just tried opening a HIRISE photo using IAS viewer from the HIRISE website and it didn't open ( I selected JP2 quicklook
IAS viewer) and got the following messages " Error in JPEG2000 Client unable to resolve host address "hijpip.lpl.arizona.edu"

and "unable to init IAS_TCPclient for server/port:hijpip.lpl.arizona.edu/8064"

Obviously something is up with IAS or the Hirise site at present

Yes, (here) it stops when the main window has opened and it has displayed sporadically a "Asynchronous Warning".

Thanks everyone who responded, appreciate it. So does my PC; it was *this* close to being hurled out the window...

The dark areas seen around most new martian impact craters are not ejecta features, but rather blast zones. The impacts basically blow away the dust on the surrounding surface, making it appear dark compared to the adjacent dust-mantled surfaces.

More beauties here: http://www.spaceflightnow.com/news/n1007/15hirise/

Somewhere recently we were discussing the possibility of using super-resolution with scanning cameras, specifically HiRISE. I did an experiment using pictures of the old Spirit lander. I tried finding images of other places at Meridiani - Beagle crater, Eagle crater... but the difficulty was finding multiple high quality images of the same location with comparable lighting and atmospheric conditions. Despite what you might think there are not many places where the coverage is OK for this. For instance, Opportunity can be illuminated from either the north or the south at different seasons, and that wrecks any chance of combining images effectively. If you compare the three raw images you can see how each one samples the target slightly differently.

Anyway, here's a composite of five images of the Spirit lander, compared with the three best images of the set (the other two are less satisfactory in image quality and lighting). I'm using the versions which are not map projected, but I have then had to do some work myself to register them reasonably well.

The composite was made by enlarging to 4x the original scale and registering, but without the addition of sharpening any layers. It shows some promise, I think, but the process would benefit from specially targeted images taken at the same season. Not very likely in my opinion!

Phil

Click to view attachment

Thanks Phil. Here was your previous post.

This is a concept that fascinates me and I believe what you did here shows there is some promise to this. Long before I learned of the super-res application in digital images, I penciled out an analogous process for film photography that I never got around to experimenting with. I won't clutter up this discussion with it. Meanwhile I think I'm going to go try this with some distant horizon photos here on Earth.

Oooh, that's pretty...

Click to view attachment

(crop from ESP_018827_2640 )

Looks like a LOT of rock fell from the scarp face, slammed into the ground below, exposing some ice beneath the surface..?

Although I'm not totally sure I agree with the ice part of the interpretation (because that spot in the fan should be an area of deposition, not exposure, if I'm seeing things correctly), that is a well spotted find!

Hmmm. Good point about the deposition, hadn't thought of that... Just thought it was a fascinating view.

Wow... just spotted this is my 4000th post. Doesn't time fly when you;re having fun?

'Dry water' has just been in the news: http://www.telegraph.co.uk/science/science...-dry-water.html

Apparently if you subject the powder to pressure you can squeeze the water out of it. What I don't know is whether this form of water is more resistant to sublimation under Martian conditions than ordinary ice. It does make me wonder though if something akin to 'dry water' could be present in Martian sediments. If so then the transient appearance of ice in avalanche debris might not be out of the question.

Great work Phil ! You are really the leading landing sites imaging cartographer ! CONGRATULATIONS.
Although they are not of your quality work, I did also some tries in 2007 combining several HiRISE images together to get more details for Viking and MPF :
- VL1 : http://www.unmannedspaceflight.com/index.p...ost&p=97402
- VL2 : http://www.unmannedspaceflight.com/index.p...ost&p=97712
- MPF : http://www.unmannedspaceflight.com/index.p...ost&p=97572
Enjoy !

So maybe there were chunks of ice that came down with the avalanche, and those whitish areas are the remnants of the last of them as they sublimate away. That would mean it was a recent avalanche, but we have caught them in action before...

..has been around since 1968. It is the "potential" application extensions that made news.

Official ACS press release here.

It is basically a hydrogel, except it is encapsulated in silica rather than in a polymer. (Think of it as teensy drops of water surrounded by a silica coating.) The silica prevents evaporation, but allows the diffusion in of gases through the silica barrier. (I'm guessing the strength of the water network prevents the individual water molecules from easily escaping.)

I'm not sure how easily this could be formed naturally on Mars....

Yeah, that looks like a pretty unlikely substance, all right.

Hmm. Why does it have to be ice? We've seen Spirit's bum wheel churn up all sorts of bright deposits, including white stuff. Maybe it's a big deposit of MgO, or even CaCO3. If so, dust deposition will gradually cover it up.

The blue color is typical of ice in HiRISE "enhanced" color images. These cliffs are along the margin of the polar cap and are composed of mostly ice (H2O) with coloring/coating by dust. So I think the blue is exposing clean ice from broken blocks that fell to the base of the cliff. What is really hard to appreciate from these images is just how steep and tall these cliffs are...

About 700m (2500 ft) and darn near vertical.

Don't really want to start a new topic, so I'll put this here. I've noticed that the weekly releases of new images on the uahirise.org website have only had one extended phase (ESP prefix) image per week, with the rest being primary science phase (i.e., older) images. I found something from the September 2010 MEPAG meeting in a presentation titled "Current Orbiter Capabilities for Future Landing Site Selection" that might help explain this:

"HIRISE: Team has used longer and more frequent warm-ups to compensate for increasing ADC (analog to digital converters) bit flip errors. Considering an onboard annealing sequence which ground testing indicates could reduce errors by breaking up and dispersing the ADC contamination."

Later in the presentation it says "need to use the capabilities conservatively where instrument and/or spacecraft limitations dictate." Also of interest is where it reports CRISM capabilities have decreased because of degradation of its gimbal (used for high resolution) and coolers (needed for IR observations). I don't think these degradations are reversable.

Hopefully, HiRISE can successfully do the annealing fix before maximum data transmission rates are reached again next year.

Rats. Nothing serious (yet), but it always hurts to see spacecraft begin to age.

At least the restart issue seems to have been cured, so hopefully the ADCs can be healed as well.

I should add, for those who are interested in CRISM, that the same presentation said the following about future CRISM operations:

"Plan: Use full VNIR/IR capability for 2 weeks every other month in mini-campaigns focused on high priority items(especially during periods of higher data rate)
--VNIR-only mode can be used at other times (but avoid major dust events)
-----VNIR (0.4 to 1.1 micrometer) aqueous mineral signatures are limited to ferric minerals
Bottom Line: Full-resolution VNIR/IR targeting reserved for high priority targets"

It's sad to see the instrument in decline, but cryocoolers like CRISM's are hard working pieces of machinery that can't be expected to last forever. They sure did a good job until now, though.

Click to view attachment

Colourisation of 'rock bridge' seen on one of today's new HiRISE releases (seen before, but still cool!) http://hirise.lpl.arizona.edu/PSP_001420_2045

Some stunning pics of the interior of giant Mars pits...
Link : http://news.nationalgeographic.com/news/20...636_600x450.jpg
Click to view attachment
Enjoy !

Very nice detail. Any idea of the depth of those pits? A second image would give a stereo pair; or if we knew the illumination geometry, the shadows would do it.

Steve M

Here's the page at the HiRISE site: http://hirise.lpl.arizona.edu/ESP_019997_1975
Look at the bottom for some geometry info.

Well the info lists PSP_003317_1975 as an anaglyph product for the image this enhanced clip has been taken from so one of the wizards here might be able to reprocess both similarly and then produce an anaglyph, the convergence angle looks pretty high to me but I'll let others comment on whether that makes this unusable or not.

This is the link to the full anaglyph image.

Even without the enhancement it should be not a problem to calculate the depth of the bright sunlit segment.

Approx 300m across and 180m deep - I did the trig on the distance from the side to the shadow using the illumination angle some time ago.

Thanks for the nice stocking stuffer. You guys are amazing.

Steve M

Its very easy to imagine the bottom of that hole continuing as a lava tube under what seems to be an overhang at the right of that image, and possibly all the way through to the left hand side. May be an illusion of perspective and lighting though.

p