Burmese
Aug 4 2005, 01:09 PM
Well, with Oppy on solid ground now I think we can say she has officially arrived at the Etched terrain.
On a side note, is it my imagination, or is the dust in the air clearing a lot the past few days? I haven't seen a shot this clear in ages...or perhaps this etched terrain is on slightly higher ground than the surround sea of dunes?
http://marsrovers.jpl.nasa.gov/gallery/all...47P0607L0M1.JPG
MahFL
Aug 4 2005, 01:22 PM
Oppy should be able to traverse more quickly over this rocky ground. Is Victoria peeking up from the horizon ?
Tesheiner
Aug 4 2005, 01:30 PM
> Oppy should be able to traverse more quickly over this rocky ground.
Yes, but see that there are more sandy terrain until we reach Erebus.
> Is Victoria peeking up from the horizon ?
As already said before, Victoria is below the current line of sight.
It won't be visible until a point more or less at the half-way between Erebus and Victoria.
RNeuhaus
Aug 4 2005, 02:55 PM
I see that around there, etched terrain, there are more outcrop than the north way from the Endurance crater. The question is why it is so?
1) The land is higher than the north?
2) This zone has stronger or more often winds?
3) The water started to flow first around Erebus?
4) "By that time there were more Roman cart traffic?
Rodolfo.
Richard Trigaux
Aug 5 2005, 09:50 AM
With my opinion Erebus, like Bonneville, is not a major scientific target, as it is filled with sand and probably dangerous to try to descend in. So it is possible that they even not attempt to get closer, taking a short cut through etched terrain toward Victoria. The later is anyway an important target, at it may exhibits a much thicker layer of evaporites than Endurance. So the situation is similar to Endurance, but there may be no way to descend into Victoria, or no way to get out.
At last we are now sure that etched terrain is exposed layers of evaporites.
But with RNeuhaus I wonder why terrains are so different, while sharing the same geological properties (20-40cms of sand on evaporites):
-Near Endurance, flat terrain with only small ripples
-Near Viking, larger dunes
-An now round Victoria-Erebus, dunes separated by troughs hollowed down to the evaporite layer.
Would it be wind channels on Mars? And why?
Maybe the ration sand/blueberries is responsible for the dunes variations? or some component of the evaporites?
Bill Harris
Aug 5 2005, 10:47 AM
Erebus is potentially an important target since it is a deep excavation in the Evaporite sequence which has much of the ejecta weathered and eroded away. We are essentially left with a big road cut: although the interior of Erebus is sand-filled, the walls are visible With Victoria, it is newer and fresher and has a huge ejecta blanket obscuring details.
IMO, a significant target here ought to the "dark basal unit" (D1, D2 and those &%$# dark angular pieces we see) since it is something we didn't see at Endurance.
--Bill
TheChemist
Aug 5 2005, 11:44 AM
Let's see what the science instruments tell us about the etched terrain outcrop.
It seems the weekend will be spent there :
Cugel
Aug 5 2005, 11:03 PM
QUOTE (Bill Harris @ Aug 5 2005, 10:47 AM)
Erebus is potentially an important target since it is a deep excavation in the Evaporite sequence which has much of the ejecta weathered and eroded away. We are essentially left with a big road cut: although the interior of Erebus is sand-filled, the walls are visible With Victoria, it is newer and fresher and has a huge ejecta blanket obscuring details.
IMO, a significant target here ought to the "dark basal unit" (D1, D2 and those &%$# dark angular pieces we see) since it is something we didn't see at Endurance.
--Bill
Bill,
Looking at the map there might be some pretty hefty dune fields between Oppy and those targets (D1, D2). Driving through Erebus itself seems totally out of the question, so how likely is it that we can reach these outcrops? On this side of the crater there doesn't seem to be so much interesting stuff, does it? And how much topography does the etched terrain actually offer? Between this location and Victoria it seems to be as flat as a pancake. Maybe this is enough reason to put the pettle to the metal and try to reach Victoria ASAP?
Bill Harris
Aug 6 2005, 01:34 AM
There may be dune fields, but there is also the evaporite pavement along the north side of Erebus, which might be easily travelled. We'll see what it looks like once we get to Erebus.
--Bill
Richard Trigaux
Aug 6 2005, 08:22 AM
Bill,
the evaporite pavement near Erebus is already known, and there is no hope to go deeper in Erebus than in Endurance, so I think it is why Erebus is not an important science target.
On the other hand, there is this pavement you mention along the norh side of Erebus, that may be easily traversed. (At rough guess, as it seems that there are many "Anatolia type" pits and cracks in the etched terrain). If they choose this path, they could spare some days to have a look into Erebus.
What makes Victoria very interesting, is that it is much deeper than Endurance, and so deeper layers of evaporite may be exposed, eventually underlying layers of another nature (which seem black in comparison with the evaporites). So They will certainly try to descend into Victoria, even if they could never get out of it. A similar bargain was made when discussing about descending into Endurance.
dilo
Aug 6 2005, 02:25 PM
New PanCam images!
This is the full-res stitch from L2+L7 filters:
Click to view attachment
Vladimorka
Aug 6 2005, 04:13 PM
DEChengst
Aug 6 2005, 04:48 PM
QUOTE (Richard Trigaux @ Aug 5 2005, 11:50 AM)
So it is possible that they even not attempt to get closer, taking a short cut through etched terrain toward Victoria. The later is anyway an important target, at it may exhibits a much thicker layer of evaporites than Endurance. So the situation is similar to Endurance, but there may be no way to descend into Victoria, or no way to get out.
You wouldn't need to go into Victoria crater to examine the deeper layers. After all Victoria is a crater so you could examine the ejecta to measure the same stuff. Ofcourse this wouldn't give you direct information about the depth the stuff came from, but miniTES might help there. Also I think it wouldn't be a big deal if you could get in, but couldn't get out. I guess that other stuff that's different enough from what we've already seen to make it scientifically worthwhile, is probably way too far away to reach it. So going into Victoria and dying there may be very well the right choice.
Jeff7
Aug 6 2005, 05:16 PM
QUOTE (dilo @ Aug 6 2005, 09:25 AM)
New PanCam images!
This is the full-res stitch from L2+L7 filters:
Click to view attachmentYikes, some of those dunes look pretty darn big.
Loads of exposed rock all over the place here too. Hopefully the wind will have granted us safe passage between the dunes. I too would like to see Victoria. I wonder how many Pancam shots it'd take to get a rim-based panorama of
that.
um3k
Aug 6 2005, 10:57 PM
QUOTE (Jeff7 @ Aug 6 2005, 01:16 PM)
Yikes, some of those dunes look pretty darn big.
Loads of exposed rock all over the place here too. Hopefully the wind will have granted us safe passage between the dunes. I too would like to see Victoria. I wonder how many Pancam shots it'd take to get a rim-based panorama of
that.
The same number of shots that it would take to get a panorama of anything else.
deglr6328
Aug 6 2005, 11:15 PM
QUOTE (Vladimorka @ Aug 6 2005, 04:13 PM)
Wow it looks really deep!
Jeff7
Aug 7 2005, 01:36 AM
QUOTE (um3k @ Aug 6 2005, 05:57 PM)
The same number of shots that it would take to get a panorama of anything else.
I thought it had some kind of higher res mode. I guess that's that super-res technique that I'm thinking of. Hm.
Stinks that the rovers haven't got zoom lenses. But I suppose that's just one more thing that could fail.
babakm
Aug 7 2005, 03:45 PM
What previously appeared like outcrops on the South and West sides of Erebus are looking more and more like large dunes on the flat "pavement that" Oppy is standing on right now. Certainly deserves a closer look, but not as exciting as I originally thought.
Sunspot
Aug 10 2005, 11:58 PM
Bill Harris
Aug 11 2005, 02:24 AM
Whew. Look at the Sol 549 MI's of the RAT hole done on Sol 546.
This is super-weird.
--Bill
ElkGroveDan
Aug 11 2005, 02:36 AM
QUOTE (Bill Harris @ Aug 11 2005, 02:24 AM)
Whew. Look at the Sol 549 MI's of the RAT hole done on Sol 546.
This is super-weird.
--Bill
OK Bill I'm looking. Help me out here. I always enjoy a good weirding-out at the end of the day, but I'm not seeing it.
Is this the MI series you are talking about?
http://marsrovers.jpl.nasa.gov/gallery/all...47P2936M2M1.JPG
Decepticon
Aug 11 2005, 02:48 AM
I wish they would clean out they holes they just finished Rating.
Wouldn't it make sense to see what you just bored out!?
deglr6328
Aug 11 2005, 02:56 AM
I don't think they CAN clean it out. The stuff is so soft and crumbly its like boring a hole in a cake and then trying to brush the crumbs out of the hole. The wire brush itself is stiff enough to keep dislodging more material from the bottom of the hole!
And if the hole is nearly flat horizontal there's nowhere for them to fall after they have been brushed "away".
mike
Aug 11 2005, 05:29 AM
It's not necessarily all that soft.. if it were consistently that soft, they could just use the brush and ditch the RAT altogether. I suppose it's possible that every rock has a thin hard outer shell covering a largely soft interior, but that seems unlikely to me.
They could at least try to brush one of them. It is odd that they haven't ever tried.
deglr6328
Aug 11 2005, 05:34 AM
Oo-ee, gooey, rich and chewy inside...
Golden, flaky, tender cakey outside..
Wrap the inside in the outside.........
Sorry, had to.
dvandorn
Aug 11 2005, 05:41 AM
Now, there's an interesting new perspective on Areology -- that Mars is one giant Fig Newton!
And who knows -- maybe there are chocolate fudge volcanoes on Venus...
-the other Doug
dilo
Aug 11 2005, 05:58 AM
Now it seems she fully reached the highway!...
Sol549
Tesheiner
Aug 11 2005, 07:45 AM
Near this point:
Click to view attachment(
Original navcam picture from sol 543)
Edited: And if previous estimations for sol 543 position were accurate, we are about to leave the highway for another 100m of "desert crossing" until standing again on rocky terrain.
Bill Harris
Aug 11 2005, 08:45 AM
QUOTE
Help me out here. I always enjoy a good weirding-out at the end of the day, but I'm not seeing it.
Sol 546 image of RAT: clean, with lots of interesting details seen.
Sol 549 image of RAT: cuttings blown into hole.
Unless I'm looking at a second RAT hole.
Data point: it is especially windy at Meridiani.
--Bill
Sunspot
Aug 11 2005, 09:08 AM
They might have used the RAT again on the same hole to make it deeper.
TheChemist
Aug 11 2005, 09:39 AM
It does not look deeper though ...
Gee, two sols of images missing (547, 548), and a RAT hole covered in sand.
Do you think we had a major "cleaning event" that was more fierce than the previous ones ?
Bill Harris
Aug 11 2005, 12:28 PM
And if you look closely you can see some of the RATted blueberries faintly through the blown dust, so I think this is the same hole.
Given the dustdevil activity at Gusev, I'd suspect similar aeolian activity at Meridiani. We may see fewer (or no) DDs here because Meridiani is less dusty, being paved in blueberries. Recall the rapid changes on the rover tracks at Purgatory-- within a few days, the underlying dust was streaking away from the disturbed areas.
--Bill
PS-- Oppy did take a series of solar panel MI's, so we may know if there was a cleaning event soon. And we can check the solar panel output as it has been decreasing.
djellison
Aug 11 2005, 12:48 PM
It's the same hole for sure - but wow - lot of dust dumped in there
One would hope that if the nearby dust was blown INTO the hole - then dust would also be blown OFF the rover
Doug
garybeau
Aug 11 2005, 10:43 PM
It looks to me like they went back in with the brush. Many of the features looked pitted rather than covered with dust.
Click to view attachment
mike
Aug 12 2005, 12:59 AM
Yeah, in hindsight NASA has surely brushed at least one RAT hole.. So ignore what I wrote about whatever, blah blah
djellison
Aug 12 2005, 06:48 AM
Back in with a brush and made it filthy? I dont think so. The clean rat hole is before the dusty rat hole chronologically. Dust deposition makes a lot more sense to me
Doug
Bob Shaw
Aug 12 2005, 09:53 AM
QUOTE (djellison @ Aug 12 2005, 07:48 AM)
Back in with a brush and made it filthy? I dont think so. The clean rat hole is before the dusty rat hole chronologically. Dust deposition makes a lot more sense to me
Doug
Doug:
It looks less like dust deposition to me than the matrix breaking up, with the smooth surface disintegrating into clumps. At the risk of setting another wild goose chase off, I wonder whether static charges could have built up during the RATting which made the very fine particles dance about. I have yet to be convinced about macro-scale aoelian effects (microscopic dust layers, fine - it's just the big chaps that I have my doubts about!).
Bob Shaw
Bill Harris
Aug 12 2005, 10:44 AM
I'll have to stand over in the confused side of the aisle, too. Initially I saw this and thought "cuttings blown in", but I swear, the surface does look pitted and eroded. Thsi may be an optical illusion, and I'm waiting for more MI's.
--Bill
djellison
Aug 13 2005, 06:27 PM
jvandriel
Aug 13 2005, 06:47 PM
A 360 degree panoramic view of Opportunity in the middle of the bedrock.
Taken with the L Navcam on Sol 550
jvandriel
dilo
Aug 13 2005, 08:27 PM
QUOTE (djellison @ Aug 13 2005, 06:27 PM)
Strange crack in the terrain -
Yes Doug, you can see it also in Sol550 jvandriel Panorama (Oppy traversed it) and in previous Sols I noticed other linear structures partially hidden, eventually related to this:
Click to view attachment Click to view attachmentMy idea is that there is a large "macro" crack system connecting many outcrops, and running below the dunes (we should think to a unique cracked pavement partially covered by dunes, in fact
...
They must be deep too and I strongly suspect they are the cause of "minicraters", as suggested by this image of aligned collapsed sand holes on the side of that dune!
Click to view attachment(I never trusted to minicrater explaination...)
Bob Shaw
Aug 13 2005, 09:01 PM
Dilo:
Very interesting - a sort of limestone pavement, Karst style topography below the dunes... ...hmmm.
And I never really bought the mini craters, either!
Bob Shaw
Myran
Aug 13 2005, 09:18 PM
QUOTE
djellison said: Strange crack in the terrain
QUOTE
dilo said; They must be deep too and I strongly suspect they are the cause of "minicraters", as suggested by this image of aligned collapsed sand holes on the side of that dune!
There sure are a crack there djellison, and agreeing with dilo, I was never comfortable with the idea of miniature impact craters.
Opportunity did pass a series of sinkholes on the way to Endurance suggesting there are a karst bedrock below. The minicraters might be paritialy filled sinkholes and the cracked lines like the one djellison pointed out could very well have come from underneath.
dilo
Aug 13 2005, 11:32 PM
Starting from Jvandriel last Pano, I made a magnified vertical projection (5 cm/pixel) in order to better identify the macro-cracks:
Click to view attachmentHere I tried to identify them, with possible (not sure) connections:
Click to view attachmentIt seems they form an (approximately) orthogonal grid, with one of the two directions going toward Erebus...
tty
Aug 14 2005, 06:04 PM
QUOTE (dilo @ Aug 14 2005, 01:32 AM)
It seems they form an (approximately) orthogonal grid, with one of the two directions going toward Erebus...
Seems reasonable if the cracking is connected to the Erebus impact. Intuitionally I would expect cracking around an impact to be either radial (if caused by the uplift of the crater rim) or concentric (if caused by the overpressure/underpressure couplet of the expanding shock-wave).
tty
Bill Harris
Aug 14 2005, 09:10 PM
QUOTE
It seems they form an (approximately) orthogonal grid, with one of the two directions going toward Erebus...
Not surprising or unusual. A strain ellipsoid shows that a deformation will produce a set of orthogonal fractures. Question is, what was the stress that produced this strain?
The anatolia-Karst lineaments are interesting because they have the appearance of solution cavities along a joint system. Interesting, because you need liquid water in quantity to dissolve the evaporite.
--Bill
djellison
Aug 14 2005, 09:34 PM
QUOTE (djellison @ Aug 12 2005, 06:48 AM)
Back in with a brush and made it filthy? I dont think so. The clean rat hole is before the dusty rat hole chronologically. Dust deposition makes a lot more sense to me
Doug
QUOTE (SS)
It looks as if we had never brushed it, though we always use the RAT brushes to remove the cuttings from a hole. What happened, apparently, is that there was a pretty substantial wind event sometime between Sols 546 and 549 that blew a bunch of cuttings back into the hol
Doug
Bob Shaw
Aug 14 2005, 09:41 PM
QUOTE (djellison @ Aug 14 2005, 10:34 PM)
QUOTE (SS)
It looks as if we had never brushed it, though we always use the RAT brushes to remove the cuttings from a hole. What happened, apparently, is that there was a pretty substantial wind event sometime between Sols 546 and 549 that blew a bunch of cuttings back into the hol
Doug
Doug:
Well, I suppose we *did* see those un-enhanced Dust Devils...
Bob Shaw
TheChemist
Aug 15 2005, 12:47 PM
Any information for the total lack of images from Sol 547-548 ?
djellison
Aug 15 2005, 01:00 PM
I guess we'll see with the next update at JPL - bad uplink perhaps - low priority imagery - who knows.
Doug
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