I'm expecting to see strong tectonic effects on both Pluto and Charon. I think tidal effects will have caused a lot of surface disruption on both bodies.

I also think it's possible that Charon, at least, may resemble Umbriel as a body that has been roughly re-assembled from the crushed remnants of an earlier body. The total angular momentum of the Pluto-Charon system resembles that of the early Earth-Moon system, which supports the idea that Pluto and Charon have a similar big whack kind of history. Pluto may show some very interesting signs of a post-impact redifferentiation, but Charon may be just below the size limit to have re-differentiated. It all depends on how long ago their big whack occurred, and the materials involved, of course, and while we have some hard compositional data, it's not exact enough to plug into a pretty formula and get Pluto/Charon out the other end.

So, I expect to see what we're going out there to see -- something unlike anything we've ever seen before.



-the other Doug

Well.

We seem to have, if not an answer, at least more information. Carbonates have been detected via evolved gas analysis by TEGA and by their distinctive crystalline structures in the only useful AFM image I've seen. They seem to be tiny grains in the soil (at least in the soils at the Phoenix site), and make up (if I heard the quote correctly) something like 6% of the samples analyzed.

So, we now have direct evidence of both the presence of carbonates and of their current structural state in the regolith. I understand the perils of globally generalizing to multiple soils based on what is seen at this admittedly non-representative location... but we're seeing enough carbonates here to at least start asking questions like:

A. How much carbonate rock is ground up into the soils of Mars?

B. For a given range of estimates of (A.) above, how much carbonate rock would have to have been emplaced and subsequently eroded into dust to account for the total mass? (i.e., are we talking about massive deposits from large ocean beds, or small emplacements in scattered lakes and small seas? Or just a few scattered crater lakes here and there?)

C. For a given range of estimates of (B.) above, and with a given range of atmospheric models, how much standing water had to have been available to form the estimated mass of carbonates, and for how long did the standing water have to persist to form that mass?

D. To what degree would a competing sulfur dioxide cycle have modified the known terrestrial example of carbonate formation?

I, for one, would feel comfortable designing a lander (or series of landers) designed to give us enough information to start answering those questions. And I think these are important questions in understanding the climate history of Mars.

-the other Doug

What amazes me is not that we're seeing dust devils -- as Doug said, it's all a matter of relative temps, as long as the differential is of the right magnitude, it doesn't really matter what the overall temperature state is.

No, what amazes me is that there doesn't seem to be any albedo impact from these DDs. In other regions, DD tracks are quite obvious and even prominent. Here, there was no trace of such DD "leavings" in any of the HiRISE images of the area.

It's not because the soil is of uniform albedo -- we can see very clearly that the soil disturbed by Phoenix's landing thrusters is much darker than the undisturbed soil. Also, soil disturbed by impact from the heatshield and backshell shows a distinct darkening.

Why, then, if DDs roam these plains, are there no DD tracks?

That's the really fascinating question here, to me.

-the other Doug

Ummmm.... oops?



-the other Doug

Ooom-pa!
Ooom-pa!
Tickety-ay!
We're going to Endeavour,
We're on our way!
Ooom-pa!
Ooom-pa!
Tickety-tipple!
Let's hope we don't get
Stuck in a ripple!



-the other Doug

"Boil that dust grain! Boil that dust grain! Boil! Boil! Boil! Boil!"



-the other Doug

I'm all for the Fourier transforms and such, but I also think it's important to check these areas visually, as well. And for one good reason -- almost any mathematical analysis is no more reliable than the base data it has to work with.

I have in mind the following scenario: We run Fourier analyses transverse to the predominant ripple orientation, since that's what gives you crest-to-crest distances and also height estimations. But it also fails to capture, in any meaningful way, the same type of information for the crossover ripples that close off all the inter-ripple lanes after only a few tens of meters.

Remember how we progressed through the Etched Terrain? The inter-ripple troughs would run for 10 to 20 meters, and then a crossover ripple would close off that lane. We had to then climb over a ripple to get to the next best trough over, one side or the other, if the crossover ripple appeared impassable (and it often did). When I look carefully at the full res images of some spots along the south route, I see the same kind of crossover ripple activity, and thus we'll see the same need to climb these ripples if we want to continue to move.

But because of their deviation from the general north-south orientation, I'm concerned that perhaps Fourier analyses aren't likely to collect enough data about these ripples to be informative of the real trafficability. That's why I think we also need eyes looking through these mazes, to find likely routes that involve climbing over ripples we're certain Oppy can handle.

But, on that score -- if, as Paolo has said, we have to keep in mind the 5-wheel scenario, we're really going to need to know just how easily a 5-wheeled Oppy is going to be able to climb or cross ripples. Without some feel for the real impact dragging a wheel will have on crossing ripples, I don't know how easily we can project a safe path into heavier ripple fields.

I will say this -- I've taken another good full-res look at the terrain to the east-northeast, and while it looks very smooth at lower resolutions, when you look at it in full res you can see it's covered with ripples to at *least* the degree we saw at Viking and Vostok, and they, too, have a predominant north-south trend. If we can't handle moving steadily transverse to ripples of that size, then I guess the south route may be the best of a not-wonderful set of choices after all.

Actually, one of the bigger reasons I had for wanting to take the east-northeast route above the worst of the ripple fields is that there is actually some exposed outcrop on rim remnants at the very northern extent of Endeavour's rimwall. What we see along the northwest quadrant looks a lot like a rim landform eroded way down and then covered over by the same evaporite groundcover that we've been seeing all along. Just seems to me that it's overall less mileage to more ancient rimwall outcrops if you go by the east-northeast route, since you won't have to backtrack back 5 km north to get to them in the northern rimwall, or go yet another 10 km south to get to outcrops on the southern rimwall... Of course, HiRISE images of the various sections of the rimwalls will help us decide just what we're actually targeting first at Endeavour, so perhaps we should wait for those before making the final decision as to the direction from which to approach.

-the other Doug

I'd just really like to know if the engineers over at SpaceX have even considered a set of small retro-rockets on the first stage, to ensure a clean separation and no recontact of stages after staging.

That's the solution von Braun and his team used in the Saturns, and there was not a single case of recontact occurring in that program...

-the other Doug

Not in the kind of resolution needed to actually see and characterize the ripples. For that, you need the HiRISE camera. (At least, if the MEX cameras, even the HRSC, can image something as small as the ripples in enough detail to do a stereo image that gives you the size and extent of individual ripples, I'm certainly not aware of it...)

-the other Doug

Well... the only reason I don't support the south route is that I've been looking at it from the point of view of driving a rover that's dragging one wheel. I'd bet that we can get 100+ meters a day in such a configuration, but only over the relatively flat, almost-no-ripple kind of terrain we see to the east-northeast.

Phil's images do a wonderful job of showing that there are areas that aren't much worse than what we saw in the Purgatory area -- but my concern is that when Oppy's wheel fails, we need to be somewhere that won't immediately trap us. I simply don't think that Oppy will be able to cross the lowest ripples in a Purgatory-like area while dragging a wheel, and I see enough Purgatory-like ripple country in the straight south route to believe that, even though it would be perfectly trafficable for Oppy with six good wheels, it will become completely impassable with one bad wheel.

I guess I'm trying to figure out a good way to get Oppy to Endeavour even if a wheel fails. The south route looks like a good route only if no wheels fail. I'm concerned that it will become a rover trap when the wheel fails.

Then again, the only metric by which I can try and forecast wheel failure is what comes out of the MER teams -- and since they decided to get out of Victoria while they still could, I guess I figured the failure was fairly imminent. If it's only imminent while Oppy is inside a crater, nothing in my available data would tell me that...



-the other Doug

I've looked at it from a trafficability standpoint on pre-HiRISE images, but assuming the darker, almost non-textured plains to the east-northeast of Victoria are analogous to the plains around Eagle and Endurance (which they resemble), it seems to me that a good route skirts along the northern border of the ripple fields that lie in the direct path to Endeavour, and then drops pretty much straight south to the north rim of the big crater.

Basically, head out north-northeast, go straight east along the flat ground north of the ripple fields, and then duck south when you're due north of the north rim of Endeavour. When the ground rises, you're there.

It keeps you out of the worst of the ripple fields for the entire trip, it brings you down onto a slightly more pronounced portion of Endeavour's rim than its northwest rim, which is almost entirely buried. It's a little more actual mileage, but stays on that flat, firm tarmac for almost the entire drive. I think that might be a good idea, especially if you have to drag a wheel. I have the nagging suspicion that if Oppy started dragging a wheel, it would never be able to safely cross a good-sized ripple again...

-the other Doug

I don't know whether to laugh, cry or wonder whether or not there ought to be some kind of investigation into the (what appears to be) serious underperformance of the TEGA itself and the sample delivery system associated with it.

Was it actually not possible to anticipate the clumpiness and stickiness of ice-rich soil? Or was the possibility just not considered?

I'm not really criticizing, I'm more in wonderment... it seems an awful lot of time, energy and money to spend to deliver a system to the surface of Mars, sitting directly over Martian ice, which seems incapable of running analyses on said ice...



-the other Doug

I seem to recall that clouds have been observed over Cimmeria for a long time, even back in the days when it was Mare Cimmerium and observed only through feeble terrestrial telescopes.



-the other Doug

Why, Douglas! You have managed to gather here the most impressive collection of intelligent, well-spoken, wildly romantic scientific rationalists I believe I have ever, in my entire life, seen park their brains on one metaphorical bench!

How can you be surprised that we would over-analyze just about anything???



-the other Doug

Last I checked, the date isn't April 1....

-the other Doug


edit -- by the way: YAHOOOOOOOOO!!!!!!!

We do have a very fine line, here -- it seems absurd to say that an imaging campaign by Hubble is proper, while an identical imaging campaign by Keck would be out of bounds.

He also explores the Cosmos who just sits and stares into the sky...

-the other Doug

Wind passing overhead can cause airflow in the bottom of a screwhole, among other things... and these are very, very small and light dust particles, for the most part. The same particles might blow up into the air when exposed to non-sheltered winds... in the "dark confines," which aren't exactly hermetically sealed, I bet the winds could create enough airflow to account for the movement we're seeing.



-the other Doug

edit -- I'm being *very* good, I think, by not pointing out how much it appears like one of the larger grains is being moved around by a teeny tiny little winged insect, which appears to the grain's left edge about halfway through the animation... and yes, I know, it's just lighting and underlying grain movement. But, man, that really looks like a tiny little mi+e-like insec+ in that one shot. Amazing what the pattern-seeking human mind thinks it can see in the darndest of places...

-dvd

I'd have to think it's wind moving the grains, young grasshopper...

-the other Doug

I think it's jus great that many people are doing something similar to what Chuck has done, though using different resources.

There have been good airplane and satellite images of most of the land surface of the Earth for many years, but with the advent of something like Google Earth (and similar other products), thousands of people whose only joy is the avocation of finding patterns in things have been searching the globe for impact crater remnants.

IIRC, there have been dozens of impact structures "discovered" (many since confirmed with ground studies) by people working through Google Earth imagery. I mean, talk about being an armchair explorer!



-the other Doug

It's a thread from one of Pathfinder's airbags.

Hey, it's had more than 10 years to get blown halfway across the planet, right?



-the other Doug

Yeah. To paraphrase any number of people, the Universe ain't safe. It's beautiful, it's fascinating, it's glorious -- but if you want safe, go hide under your bed. (And even then, you ain't safe.)

The possibility of finding an alien microbe that could do great damage is probably on the same order as the Earth passing directly through the focused emission from a nearby gamma-ray burster. Either holds the potential of ending all life on Earth. The real difference is that we can take steps to make the threat from alien microbes even more remote than it already is, while there is nothing we can do about a close GRB (or a close supernova, or the passage of a large dark body through the inner Solar System, etc., etc., etc.) except to hope for just enough warning to insert our heads deeply between our knees, so we can kiss our arses g'bye!



-the other Doug

...and according to some sources, Ganymede and even Callisto may have subsurface oceans, albeit not of the extent of Europa's.

-the other Doug

As I recall, Mike Collins noted in re the Apollo quarantine procedures that you take a very, very small number -- the chance of an organism that could destroy life on Earth being returned from the Moon -- and you multiply it by the extremely large number of the damage that such an organism would cause. The result of that equation is a small but significant number, and on that basis a certain amount of precaution must be taken.

-the other Doug

To Doug et al -- what I'm really getting at, here, I think, is how the Viking results were received. At first, the gas emission results indicated that something was undergoing life-like chemical reactions which caused various liquids and nutrients to be processed and released. However, when the holy grail of organic compounds was not detected, the results were intepreted in the context of "well, since it cannot possibly be caused by any kind of living organism, what exotic chemistry can we postulate that would account for these results?"

In other words, when we placed Martian soil in an environment that would nurture life as we know it, we got results at least roughly consistent with life being present. But when we saw no organic compounds, instead of *also* trying to follow up possible life processes that could exist within the parameters of the observation, the interpretation of the results was shifted such that life-processes were taken off the table as being even remotely possible as the cause.

All I'm saying is that as long as we insist on defining life as *only* that which is based on organic compounds, as long as our definition of life automatically excludes anything except life as it is found on Earth, we are in danger of completely missing other types of life, based on different chemistries. That's really all I'm saying.

And IMHO, the "life question" is important enough that we ought to at least be aware that we're conducting our search with our heads buried in terro-centric sands.

-the other Doug

So Falcon 9 will be using the old Titan III pad, eh? Are they also going to use the old Titan assembly building, I wonder?

-the other Doug