- veery pretty, Nirgal.

(Now, if I could only figure out where the rover is in this shot... er, what 'cape' it's sitting on... uh, or is it a 'bay?')

The name (bahia - pronounced ba-'i-a, h not pronounced, stress on second syllable) is an archaic spelling of the Portuguese word meaning "bay" and comes from "a baía de Todos os Santos" (All Saints' Bay...) (Bahia is a state of Brazil...)

Don't know if it's relevant, but it seems the name Duck's Bay couldn't be any clearer with Odave's drawing of the duck!

Yep... but it'll have two missing bright spots. I've been, and most everyone else here, has been having a great time watching one of the most interesting adventures in the history of mankind - two, not just one, little machines crawling around on a planet (old moon, it seems) for now more than two years.

It has been a time full of drama, discovery, and surprise. A steady stream of pictures that have amazed and confounded. I'll sure miss it all when these two little machines are finally retired somewhere.

One consolation - there'll be the next set of exploratory vehicles - bigger, faster and packing new abilities that'll keep us glued to the pictures they send to us.

Wow - that's hot! - both format - and the terrain view

We’ve not seen Oppy taking pictures of whirlwinds (‘dust devils’,) as conditions in Meridiani don’t seem as favorable for formation and sustenance of them as they are in Gusev.

But, what we see at the North edge of VC looks much like the tracks of atmospheric vortexes that rise out of craters at Gusev as whirlwinds, picking up dust and leaving behind a darker trail.

(Photos below at Gusev (and a snip of VC) show crater-created whirlwind tracks lasting varying amounts of time, dependent on crater size, depth and prevailing wind speed.)

First let me take a moment to say thanks to Alan (and Doug?) for getting this discussion on its own thread.

If there is one thing that stands out about Meridiani, it is the seemingly endless mega-ripples – deserving more discussion of this kind.

And, thanks Cosmic, for your most interesting contribution to the discussion! (BTW, a better link to earthsciences mega-rippling is here.)

I’m skeptical that the features of Meridiani were entirely aeolian formed, primarily because where sand and wind exist in abundance over geological time, we see pictures (like here, and here) where much larger, even mountainous, dunes form. In fact, Mars has its own ‘desert’ areas with similar mountainous dunes. But not in Meridiani? Then why not?

Secondarily, we know (or think we do) that this is an old seabed – but little discussion has centered on what would happen when that sea reached a depth of only a few feet, and then ever lower over time (as it dried up) across its entirety.

It seems more probable to me that the dynamics of an ever-shallower sea engaged two forces, both wind and water, formed what we see today – adding even more powerful evidence of it being a sea in the first place.

I don’t see water alone causing these mega-ripples, because as has been amply discussed, we don’t commonly see ripples this large under bodies of water – except near coastal areas where seas become shallower, in tidal areas and often after storms – however we do have a working knowledge of how mega-ripples form. This naval study provides much insight, as does this study of Puget Sound mega-rippling.

This NASA piece on cross-bedding concentrates on ‘flowing’ water. (Huh? One must ask, from whence to where?) Shallow standing bodies of water subjected to wind and other forces are at issue here, and that seems to have had much less attention than it ought to have had - particularly with respect to how static Meridiani has been and is today.

If we're looking for mathematical evidence of a sea on Mars, I think that some of the strongest evidence to date may be going almost entirely undocumented.

- -
Bob, lyford (others too) - keep the humor coming...

They indeed do ~look~ pristine - and to some extent, I must agree with you - there's more to the real story than we've heard or read.

I think the 'real story' is quite a bit different than many think - part of that may be that this 'old sea bed' may not be so old after all. Another part of it is that the atmosphere of Mars has changed radically (and is said to be accelerating) in recent times... just look at the rate it is disappearing now. Just a few hundred years ago it was much denser, and probably supported more radical weather (winds) than we see now.

We have this propensity to deem everything happening on Mars on a time and geological scale much the same as that of earth, and I think that's perhaps at the root of some poor thinking. Suppose, for example, that this sea had become subjected to hurricane force winds in a much denser atmosphere. It isn't difficult to see virtually the exact kind of terrain we see today, since we can see so-called 'mega-ripples' - actual large sand waveforms on the seabed near the Sable Island Bank. The waveform trough to crest measurements there, and in other places on earth, run between 5m and 10m - close to what is around Oppy.

Maybe it did the same on Mars - back when - maybe it didn't. But, there are 'earthly' examples of almost identical underwater waveforms - in the here and now. It might be a stretch to think the same would happen on Mars - but... similar forces just might create similar results.

Well, I'm not so sure the time period was long at all. From one perspective it might have all happened rather quickly - then sort of 'froze' in its current state after only a few years. We'll never know for sure - despite what some would lead us to believe.

If this was (and it appears to be) the bottom of a sea that more or less dried up at some point - what we see could easily have been created by wind-blown sea water prior to final evaporation. How long ago could such a sea have existed? We don't know for certain... it could have been there a thousand years ago, and everything could look as it does today.

Wind obviously has had an effect, but to what extent it now effects the area seems rather settled - lighter winds have moved smaller particles, leaving behind the heavier... but still more or less in the same configuration (possible) that water left it in.

But, if Oppy runs into 80-90MPH winds - such a theory goes pooof.

True! Imagine a 360 pan that features mostly one giant hole, the far side of which is still feature-indistinct, and we can’t wait to get to the far side, just to prove what we think we see... a possible route into the chaos of an abyss.

James, do you think they will back-fill the many lost segments of recent photos? And, what do you think is causing the increase in the number of incomplete images?

Yup, a $2K picture of Mars with Rover at my house would land me in court in a heartbeat. I get heavy flack over an 8x10, the priorities are so different.

"Normal people just don't overdose on multiple pictures of some damned machine running around on Mars!" "Just how many do you need?"

And so it goes...

"Spirit will remove a layer of soil up to 1 millimeter thick (the thickness of a dime)." - per this link.

Well, the pictures coming back looks like the first attempts at “1 millimeter removal” of soil thickness were fairly well mucked up. What seems to have been created is more or less a sticky-wicket of piled up soil in a deeper hole than intended.

I hope they have better results in future attempts. I'd really like to see gradual 1mm 'removal.'

Your images suggest pretty scarce possibilities for Oppy driving to the floor of this monster crater.

I’ve kept mum about my thinking that Oppy drivers will find no safe entry to descend into the interior of VC. But should that prove to be the case, I’d be among those who would be greatly disappointed.

Perhaps some may not 'get' Astro0's picture of earth - it's there, and properly a tiny dot (see my muck-up of his picture with red arrow pointing to earth below.) Yes, that's Spirit, perched on Jibsheet, and it's a sunset - but properly speaking earth, of course, wouldn't be there in the sky over Mars at that time. It is indeed a lovely picture - but one that puts earth in the picture for perspective, contemplation and simple artistic purposes.

Astro0 - correct me if I'm all wet...

(edited) - oh, was I wrong! The outcrop is Jibsheet, and it's a sunset - image from Cornell's Pamcam site.

Well, I'd be very surprised if they actually sit right where they are for the next four months - for several reasons. First, the slope nearby (dead ahead to rear of rover) allows for a better tilt toward the sun (current is 11 degrees, potential is for 15 to 18 degrees.) Second, there are so many 'targets' to get to - for 'science' - that I believe they will slowly get around to over the next few months. I’m expecting at least half a dozen moves to nearby targets.

The problems associated with moving are great - ability to turn is limited, and potential for getting 'stuck' is high, unless great care is taken. They'll have to wiggle around the dead wheel, and hence they have to pre-plan every move much more carefully than in the past. Every turn will dig up the soil around where it is made, and obviously, the big rocks in the area could become a problem in any turning sequence.

There is also the rise to the immediate west of the current location, that also offers a potential greater northern tilt - perhaps five to eight more degrees - and additional targets of interest nearby.

So somewhere in the following months, I fully expect to see a visit to that rise -which won’t entail much additional driving – but will give us new views, and many more fascinating pictures to contemplate.

One more item from THIS LINK - we ~could~ be sitting virtually in one small area for 8 months... maybe - some of that determined by lowered driving ability. Here's part of the text.

"We have to use care choosing the type of terrain we drive over," Dr. Ashitey Trebi-Ollennu, a rover planner at NASA's Jet Propulsion Laboratory, Pasadena, Calif., said about the challenge of five-wheel driving. In tests at JPL, the team has been practicing a maneuver to gain additional tilt by perching the left-front wheel on a basketball-size rock.

Spending eight months or so at Low Ridge Haven will offer time for many long-duration studies that members of the science team have been considering since early in the mission, said Dr. Ray Arvidson of Washington University in St. Louis, deputy principal investigator. These include detailed mapping of rocks and soils; in-depth determination of rock and soil composition; monitoring of clouds and other atmospheric changes; watching for subtle surface changes due to winds; and learning properties of the shallow subsurface by tracking surface-temperature changes over a span of months.

In case you haven't seen it, a new rover update was posted on the marsrovers website HERE, dated the 14th. The 'news' is that the increase in power is, "50 to 60 watt-hours per sol" - which only "gives the rover enough energy for about one hour of daytime remote science."

Unfortunately that isn't much of an increase - but it at least allows some of the 'science' that many have longed to see.

Here’s a Q&D pan from the 4/15/06 (Sol 811) pancam directory of exploratorium - a look toward Husband Hill and the edge of HP. There’s an interesting spot in the tracks here (second image below) where it looks as if the right front wheel may have failed to rotate momentarily, a few meters before it failed completely. Maybe, maybe not... it could just be a patch of soft-dust-ridge the wheels went through, and it does have some cleat marks, however they aren’t uniform.

Well - it is not near as good now as when Spirit first perched itself on the side of West Spur for the winter.

Just compare the the images below from Aug 2004 (left images) and those now (right images.)

A conversion, -80C is -112F degrees.

In a word, yes. I expect we'll see a 'most favorable' spot found (or several) that will allow the best charging of the batteries, and some movement away from (for 'science,') and back to that spot - and or other spots comparably favorable.

We will see pretty much the same routine that we saw last winter - not much movement, a lot of sun-basking, but certainly longer and closer looks at the layering and composition of interesting outcrops, rocks and composites nearest to spots that tip the solar panels best toward the sun low in the northern sky.

With the crippled 'leg' - the drivers will be limited in what they can accomplish, to some degree - but, I expect we'll see plenty of interesting work done, even though Spirit will soon be in the coldest part of winter.

One interesting thing we've learned - driving increases the heat level in the WEB, so some amount of driving (power dependent) may help the MER vehicles get through the coldest part of winter.

Thanks Bob, for the info on ‘Stitcher’ – and thanks too, jv – for the pointer to the Tech, General and Imagery postings.

I haven’t yet been able to find a free version of Stitcher, but in fiddling with autostitch settings a bit more using the guide provided by one of Tesheiner’s posts, I came up with the view below of five exploratorium navcam images dated 2006-04-10 (don’t know what Sol date applies.) I really like the ability of autostitch to figure out, on its own, where to put the images.

It looks like Spirit has only to drive a short distance now in order to sit and bask in the Northern sun and get those batteries charged up as well as the dust allows.

(edit: replaced prior image with slight adjusted...)

Thanks very much jv! I tried and tried to put that together, and nothing I did would make it right. (I use an old copy of photostitch that came with my Canon camera, and it's lousy - and I've not become familiar with all the settings on the free version of autostitch yet )

Has anyone you know tried the commercial version of autostitch? (Is it 'worth it' - at $99?) Probably is... I guess I've just not worked up the desire high enough yet.

Well... in looking at where Spirit stopped on Sol 803, the panels are tipped to the south-east... they'll not want to stop there long, I wouldn't think.

For those that can devine it from the info available, is today (Saturday here) a drive day, or is it another one of those every-other-day non-drive days?

That is good progress, Tesh. About 33-35 feet... and that little rock your circle passes over is right between Spirits two rear wheels. Will they try driving straight up over that little ridge to see if it can make it, or will they play safe and go around to the right? (would mean a shuffling right turn - and less advance next drive day.) Here's that little rock...