HiRISE and Mars Polar Lander Options

[djellison]

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

[ugordan]

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?

[Reed]

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

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.

[elakdawalla]

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.

To get the *probability* of being within sigma standard deviations you need to integrate P(k) over k from -sigma to sigma. This integral gives probability(sigma)=erf(sigma/sqrt(2))^2,
where erf is the so-called "error function".

If you plug this in to some maths software like Mathematica or matlab, or look up a table (cringe), you get:
the probability of being within 1 sigma = 46.6% the probability of being within 3 sigma = 99.5% So the numbers presently given in the blog are qualitatively right anyway, I guess but the maths fans might balk...

Anybody have a response?

--Emily

[nprev]

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).

[Mike Dorward]

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

Attached thumbnail(s)

 

[nprev]

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

[djellison]

All looks totally natural to me.

[ugordan]

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.

[nprev]

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... )

[Reed]

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.

Agreed. There are plenty of ~8-12 pixel diameter bright spots that could conceivable be part of MPL, but don't have any features that allow a definitive conclusion.

I'm still somewhat optimistic about finding it. As previously mentioned, a good part of the predicted MPL ellipse has not been imaged by HiRISE. It may be sitting there plain as day. The evolution of the Phoenix site over the next season may give us a hint as to how realistic this is. If the parachute is undetectable after the first spring, that will bode poorly for finding MPL.

[Guest_Sunspot_*]

How much of the landing ellipse did MGS cover?, I think the parachute ought to be fairly obvious even with MGS. With Phoenix landing so far down range of it's target - almost outside its landing ellipse infact, perhaps the same happened to MPL, and as others have suggested, we still don't have images of the area it lies in.

I wonder, if the failure scenario reached by the review team is correct, could MPL have survived the landing in some functional condition? Would the solar panels have been deployed? If not the lander will appear even smaller than illustrations indicate.

I know there was some excitement a few weeks after landing when reviews of communications attempts with MPL suggested they may have received some very weak signals, enough evidence at the time for them to re start communications attempts.

[claurel]

Another backshell rock sculpture from 005536_1030? Or an actual piece of MPL?


(zoom is 100%)

This sure looks bright and shiny, but I think it might be too large to be the backshell. Also, the way it's conveniently nestled into an indentation in the side of the fracture suggests a natural origin.

What is the exact size of the MPL backshell?

--Chris

[djellison]

The MPF, MER, MPL and Phoenix backshells are about 2.6 metres diameter. The Viking backshells are about 3.5m diameter

[claurel]

The MPF, MER, MPL and Phoenix backshells are about 2.6 metres diameter. The Viking backshells are about 3.5m diameter

Thanks. Looks like that rock is nearly 2x larger than the MPL backshell then.

--Chris