Is there any possibility that this could be the crash site of MPL then?
I would go for a full MPL including heat shield etc that would have hitten the ground

Tim53 said in a earlier post there's another one of those conical pits in the area suggesting this has nothing to do with MPL. If this is an impact crater, its morphology seems inconsistent with what I'd expect of a hypersonic impact into hard or rough soil. The pit itself is too large, this one is supposedly 50 meters across. I wouldn't expect a small object travelling at say 400 m/s to produce a crater that big.

If I had to put my money on it (Murphy's law!), I'd say the lander is either in the heavily clouded-over images we have now or in the rest of the ellipse that hasn't been covered yet. Other than that, anything suspicious would have probably already jumped out at the HiRISE team, at least when looking at your typical, fairly flat and dull terrain here (though I am wondering how systematic their search was so we can modify our "expectations"). On the other hand, images like PSP_005536_1030 (especially the top part of NOMAP version) have pretty big albedo variations and small-scale topography so in principle, something just might be hiding over there.

I agree on this but I thought may be heat would have melted the ice around the impact so the crater would have grown bigger.
Ok, if there's another conical pit around, unless MPL did a bounce as Soyuz TMA-11 did ...

Argh. As Gordan said earlier, "so many unknowns"! Seems as if this manifest fact will be compounded by the fact that there well might be active geology at the site; those pits sure look like something related to the CO2 geysers to me, or some other outgassing/collapse mechanism.

I might be wrong about this, but if you're thinking about heat shield heat, there might not be that much heat at all. If the heat shield is ablative, the part that heats up is the part that's ablated away, which is a mechanism for keeping the shield cool. The shield material is a very good heat insulator so it doesn't store too much heat during reentry. If you're talking about impact-induced heating, my gut feeling tells me there isn't that much produced. A Mach 2 impact is likely to compress/scatter soil rather than heat it up significantly. Also, keep in mind that water ice (if it's water) has a high specific melting heat so it would take a LOT of heat to melt that large a volume.

Yes, I concur. Ablative material (sort of "cork" as they say in Phoenix video) won't let heatshield very hot.
So, we're back on the search

I thought about the possibility that these pits might indicate sublimation of loose ice by a warm lander and heatshield landing on it (there are two in this area, IIRC - the one that Marsisimportant posted, and a smaller one some hundreds of meters away, again IIRC). But it would have to be pretty loosely consolidated, and ice has a tremendous capacity for absorbing heat. Then, perhaps the real clincher is that other regions of polar terrain show similar pits in abundance.

They are intriguing features in their own right, though.

-Tim.
P.S. Hi Rob!
PPS. Emily - I thought I was wrong once, but apparently I was mistaken!

What kind of effect would the downed lander have on the surrounding area over time? There are a ton of possibilities here I imagine, anything from growing a pit in the ice to growing a hill of dust.

A friend of mine went to Greenland a while back and he showed this fascinating, yet depressing, picture of a big hole in the snow made by a single Mars bar wrapper. MPL is not that dark though I would think.

Hi Climber,

You are correct. There was and continues to be a lot of uncertainty in our knowledge of the density variations in the altitude range that the entry vehicle does most of its deceleration (mostly between 20 and 50 km). Given that these machines enter at very shallow entry flight path angles - around 13.5 degrees for MPL - only a few percent uncertainty in our estimates of the atmosphere density means the difference of many 10s of km on the surface. The ellipse shown on the HiRISE site (made by Tim) is based on our best guess of where the vehicle was when it reached the top of the atmosphere (based on our radiometric tracking data taken in the hours and days before landing). We think these estimates were pretty good and do not depend much on what failures may have happened to the vehicle. We then use computer simulations to model entry, descent and landing using one atmosphere model (as well as slight variations in the entry initial conditions), we then do the simulation again and again using slightly different models (correctly selected statistics-wise) and then we look to see how these are scattered on the surface. The ellipse that Tim placed on that HiRISE map at the HiRISE site represents about a 2-sigma ellipse (see Emily's Blog from yesterday). So we believe that there is about an 86% probability that MPL is inside that ellipse.

Of course, people ask me; What if the cruise stage never came off? or What if the parachute did not open? What if it tumbled during entry? Well it turns out that these cases do not make a huge difference in the position and shape of the 2-sigma ellipse. It makes it a tad longer (probably moves it further south a few km as well ). As you suggest Climber, one place that we could be very wrong and would make a bigger difference in the ellipse is the atmosphere. You will also notice that the HiRISE images do not cover the right side of the ellipse. That was due to a mistake I made (an unfortunate change of longitude definitions occurred just after the post-MPL trajectory reconstruction that I was not aware of ... it resulted in our estimates of where the ellipse was painted on the surface moving a few km to the east after the HiRISE image "campaign" was well under way).

As I said before, it is there somewhere and I have some faith that it will eventually be seen. While I could be wrong (I have been many times in this biz), I doubt that it would have made a crater that did not leave equipment visibly scattered on the surface (unless subsequently covered by dust or other Mars material). Even without a parachute, it would have slowed down to very nearly it's Mars "terminal velocity" which for this vehicle is around 220 - 300 m/s (depending on tumbling attitude). That is fast but not fast enough to poke a deep hole in Mars!

If it is a needle in a haystack, I *think* it will be a bright needle. (My friends think I am an optimist.)

Cheers!

-Rob M

***************
These comments and opinions are solely those of the author and do not reflect the views of JPL, Caltech nor NASA.

Remcook,
Yes, that's exactly what I'm thinking as well. I'll bet that reflective or not, the net effect would be to make a depression in ice. If it's not reflecting the light it absorbs heat would tend to make a hole, and since the sides of the hole would be more vertical than the surface, the sides would tend to enlarge over time. And if does reflect the light, said light would mostly impact nearby, making the surface around the lander slightly hotter due to the reflections.

I'm betting MPL will be in a small depression, larger than the size of the lander, whether it landed correctly or not.

To do this properly, I created a spreadsheet on the Yahoo groups site with picture names across the top, and ppl checking them going down vertically. Post here which photos you have searched and to how far (Y pixel number), and I'll try to update the file. This way efforts can be divided appropriately.

Link here.

BTW, as a suggestion for future futile searches, adding some false positives to the mix is a good idea. Maybe 25-100 every picture might cut out the boredom, and give ppl something to score each other on.

Argh. I can't find a trace of your objects in the said image and that image is the most studied one by me yet. I also looked at the IRB version since you said there's color coverage, but found nothing remotely interesting. Would you mind showing us how your objects look (not necessarily giving locations) so we can see what they're supposed to look like?

Plus, this is just driving me crazy

Okay, here ya go!

They're in opposite corners of this cropped frame from that image. And they live near the north end of the image. In this case, north is toward the bottom of the scene.

And remember, though the file is titled with MPL and backshell in the file name, it really can't be hardware, because of the things I noted above...

...unless it is. We'll see when the sun comes back around.

But seriously, though I have looked at all the HiRISE images taken thus far, I might have missed something. I'd love to hear what all y'all might find!

-Tim.

Wow. I give up. I see nothing in that image even remotely out of place.

(Savagely beautiful, yes; out of the "ordinary", no.)

Do you have an annotated image you could post?

-Mike

I've got to hit the freeways now, but maybe tomorrow I could do that.

-Tim.

Cool. That gives us all 24 hours to find the missing lander in the image....

I'm glad I'm not in charge of these kinds of searches, because I also wouldn't have spotted anything 'unusual' in that figure...

(Has anyone else noticed that the deposit structure resembles a neuron?)

(I was kinda using that nomenclature to work my way down one axon then on to another during my search.)

-Mike

Actually, this is pretty straightforward, so no annotation should be needed. The object that I propose "might" be the lander (but probably isn't) is the "double-bump" looking feature near the upper left corner of that cropped image. The possible backshell object is in the lower right corner. In this region, there aren't many objects that look like this - though there are some. And this is the only case I've found where two suspicious objects are within a few hundred meters of one another.

This is the simulated image I used to convince myself that this might be the lander. But again, there are problems with the lighting/shading. The fixed solar panels should shade most of the upper deck of the lander if it's in this orientation and more or less "level". Also, the "downsun" solar panel would be completely shaded with the sun geometry of this image, and the object doesn't match this expectation.

Well, it took me way too long to do this, but I have finally posted a page on the search:
http://www.planetary.org/explore/topics/ma...der_search.html

There's more that I want to do, but I figured this was a good start. I, too, had had the idea of having people report which images they were searching, or ask to be assigned one, but hendric beat me to it. Still, if you want to let me know which images you are searching, do pop me a PM or an email and I'll maintain a tally.

One thing I want to do is create my own base map and see where there are areas of overlap between images. One good test for the viability of a candidate is to see how it looks under different lighting geometry, which you can do if you are lucky enough to have found a candidate near the edge of an image where it may have overlapped another.

--Emily

Just a quick one... probably nothing, of course. Same image as Tim's.

Phil

Click to view attachment

Hi Phil:

Yeah, that's the frustrating thing about this search. Some places are just chock full of hardware! ...or so it might seem.


-Tim.

So perhaps we should call this place 'The Boneyard'...

Yes, I was struck, not by the paucity of candidates but by their profusion. if any little lump might be a spacecraft it really is a boneyard. And proving anything will be really hard. Color might do the trick, though, as you say.

I liked it better in the old days when we were just comparing surface and orbital images!

Phil

Only another 10 more days and you'll do it again on the other pole

That'll be much MUCH easier with the triangulation we'll get via UHF

Doug

How accurate is that, anyway?

http://www.msss.com/mer_mission/finding_mer/ - and I'm sure it's improved since then. I'm sure it'll be enough to say 'it's in THIS HiRISE image' giving us a realistic chance of identifying the site from local features / rock patterns etc.

Doug

That's pretty cool, I didn't know the orbiting spacecraft relays could even measure the Doppler shift. Techniques like this really give the term "nailing it down" meaning.

This caught my eye, back-shell top-left, parachute bottom-right:

Click to view attachment

I don't think it can be though as they are separated by 80m, I assume the parachute lines were a lot shorter than this?


James

Yeah, more like 10m, not 80. That looks like what would happen if someone tried to fake a backshell and chute out of rock

Yeah thought so, the MPL landing ellipse seems to be littered with rock carvings of back-shells, parachutes and landers!

This is going to be hard...

This may help: http://global-data.mars.asu.edu/bin//hiris...=3&cookie=0 although the zoom is pretty limited. If you click a point with the select tool, you get a list of images covering that point. Actually finding the corresponding point on the images will still be a bit of work.

You can also select MOC images on the same site, which probably aren't high enough res to see the lander but might provide useful context.

MOC should, however, resolve the backshell and the parachute. It did with Spirit and Opportunity. When I go MPL hunting - that's what I look for. - If you compare the 'how far it got' elements of EDL, with what you should be able to find on the surface..

DOA / entry failure : Aeroshell impacts at speed, crater, probably unidentifiable.
Failure of chute : probably same as above
Chute deploys, rest a failure : chute and backshell
Lander seperates, but then fails : chute, backshell, heatshield impact site and small probably unidentifiable impact

So in almost any failure mode, the chute and backshell should be visible. What impact the climate would have w.r.t. burying them, covering them etc I don't know, but the Pathfinder chute is clearly visible to HiRISE.

Doug

What exactly are you saying?

That nature can play tricks on people. When you're looking for a backshell, all the rocks look like backshells.

Doug

Having looked at parts of the landing site with HiRISE images, some of it looks treacherous.... I wonder, had the MPL team had images with that resolution available to them when planning the landing, would they have chosen a different area?

Also, illustrations of what MPL would look like from orbit show it with the solar arrays deployed, if it did fail during the entry phase, deployment is unlikely to have happened ? - making it even harder to see.

I've now gone through all the images, all of them at half resolution except two ones (on of them being PSP_005536_1030), concentrating on rougher and brighter terrains where it would be easier to miss something. I operated under the assumption that given the jumbled look of some of the terrain with large albedo variations, my best bet would just be looking for a backshell and/or parachute. If the EDL sequnce didn't get as far as parachute deployment, finding the crash site is going to be tough to say the least. If there is a parachute and backshell somewhere, it would be readily apparent even at 50 cm/pix and this speeds up the search significantly. There was (to my eye) not a single candidate for the backshell in any of the images. Given the roughness of some of this terrain, I'd say the lander tipping over at touchdown is a pretty plausible failure scenario as well. I'm left to conclude that it either isn't located in these images (or, by some sick chance, it's in one of the data dropout gaps) or there is no backshell.

How high was MGS coverage of the landing ellipse and at what resolution? MGS later resolved the MER chutes, but that was using cPROTO.

Gordan: Check up this: http://mars.jpl.nasa.gov/mgs/msss/camera/i...nder/index.html

The resolution was about 1.5 m per pixel. "Thus, the MOC team is basically trying to distinguish one or two pixels from nearly 150 million. One team member has remarked that this is like "trying to find a specific needle in...a haystack-sized pile of needles."

ugordon:

Indeed this is a difficult search! The MOC coverage is pretty good over the terrain where MPL was expected to have touched down if all went according to plan. I can't remember the number of images that overlapped at the "candidate object" I talk about above, but it was probably at least 2 or 3. The earliest of these was taken within 2 or 3 weeks of landing, and since it doesn't show anything unusual at that location, I have to believe that the candidate is most likely a frustratingly-lander-looking natural feature. Or (and this isn't very likely), dust accumulation was so fast as to mask the brightness of the parachute that soon after landing. And even in that overly-optimistic scenario, if the lander made it to the ground and deployed its solar panels, why didn't we hear from it? At least briefly?

The MOC coverage of the MPF landing site is particularly interesting in regards to searching for MPL, because imaging the landing site began within a year of the landing. So it's possible to look at changes in the visibility of things like the parachute over time. Because the backshell and parachute weren't visible from the ground, I didn't think the bright splotch at that location taken by MOC (http://www.msss.com/moc_gallery/ab1_m04/images/SP125603.html) was anything unusual (you can't really identify the backshell as obvious "hardware" in any of the MOC images for this reason). But since there are multiple images here, taken over many years, you can see how these objects "fade" with time.

Again, the best chance of finding MPL is if the parachute did in fact deploy, as it's potentially the most expansive piece of spacecraft hardware and ought to be verifiable in MOC images taken shortly after the landing. Since nothing unusual was identified during that search, it seem more likely that the lander crashed, or it landed outside the MOC search images - which would require it to have not landed where it was supposed to. Or the chute did deply, but may not be spread out on the surface, but clumped into a small area.

-Tim.

What about if the chute deployed and failed in pieces like for the MER first envisioned chute?
May be in this configuration, the whole spacecraft slowed down so the crach was not at full speed. A failed parachute (in piece) may have never been visible to MGS and now to HiRise. So, if the spacecraft is still in the back+heat shield, are they both white? Is there any chance that the colour was not bright enought and the landing not hard enough both to be visible by MGS?

Even a shreded chute like those Boise MER tests would still be a fairly big target - and the backshell might, I expect, survive the impact - especially if the lander seperated before landing.

Doug

Thanks, Zvezdichko and Tim for the pointers. Just for fun, here's the original place MPL was believed to have been found in 2005 (see this release), seen by HiRISE (quick'n'dirty "map projection"):


Later that year, the MSSS team got another look at the candidate site using cPROTO: http://www.msss.com/mars_images/moc/2005/10/17/. It illustrates that to reasonably be able to pick up the lost lander (primarily its chute), cPROTO-like coverage would be needed across the ellipse. In other words, all is probably not lost just yet. The lack of chute detection by MGS might constrain the actual location to more chaotic terrain seen by HiRISE where the feature would not readily stand out to MGS.

BTW, is it me or are the MGS images less contrasted compared to HiRISE? Higher solar elevation in MGS images or something else?

One thing I've been wondering is how the albedo of the stuff that appears bright at other landing sites (parachutes etc) compares to the bright (frost ?) areas we see in polar terrain. Then there's the question of seasonal frost forming on things we are looking for

Gordan
Nice work, I was hoping someone would do that.

Someone wrote to correct Rob Manning's math in my blog post on the statistics of the landing ellipse -- I'm posting the comments here so that people whose minds are less dulled by parenthood can take a look and see if the criticism is correct.
Anybody have a response?

--Emily

Well...dusting off my brain here, I'd say that the critic is right but so is Rob (he says so himself). The error function basically invokes an additional Gaussian distribution overlay on the overall uncertainty, but its magnitude is pretty small in this instance. The correction does not appear to be at all significant except to purists, and in any case is subsumed by the larger uncertainty envelope (landing ellipse).

Attached is a 2X HiRISE image showing the Polar Lander resting on its side (the whiter pixels at the "top" of the shadow) and a shadow indicating an object approximately 1 meter wide and 3 meters tall. If you look closely at the far end of the shadow you can see a weak cross, which I believe to be the antennae of the spacecraft.

PSP_005536_1030_RED.QLOOK.JP2

The spacecraft is at 33802,67855

Mike Dorward

Sorry...not seeing it. Pretty sweeping claim, and you need to produce more convincing supporting evidence.

All looks totally natural to me.

This one is probably completely natural as well, but it does look interesting enough to mention. Below's a flicker gif between an object in 005536 and Spirit's backshell for reference. The sizes match pretty well, but the location seems too convenient as there are occasionally other round objects inside these trenches, especially in "corners" like this one. Non-map projected image rotated 180 deg to get a more reasonable illumination angle from top left.

Cool...but I think we're getting into some deep kimchi here in a lot of ways. We don't know the rate of dust deposition in this area, for one, and geometrically similar objects are abundant.

Hate to say it, but I'm becoming more and more convinced that somebody's gonna find MPL by tripping over it around 2430.

(Usually when I say such things I'm immediately proven wrong, so here's to the power of negative luck... )