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Unmanned Spaceflight.com _ Spirit _ Home Plate (second round)

Posted by: Tesheiner Sep 6 2007, 01:55 PM

Well I think that Spirit has finally left Silica Valley for good --please don't tell me that we should go back again to Silica Valley because of another turned up soil deposit or cracked rock-- and is about to start another science campaign at Home Plate, so it would be time to start a new thread devoted to this period of time.

I said on a previous post on the older thread that it looks like the plan is to traverse the top. Digging on an http://www.planetary.org/news/2007/0531_Mars_Exploration_Rovers_Update_Spirit.html (at TPS) I found this reference:

QUOTE
"The general desire is to stay on top of Home Plate, but follow the outcrop exposures around to the portion that everybody really wants to get to -- the far end or southwestern portion of Home Plate," said Yen.


Edited: This http://www.planetary.org/news/2007/0228_Mars_Exploration_Rovers_Update_Spirit.html might apply too.
QUOTE
At that time, the team will have to decide if Spirit will cross the diameter of Home Plate, roving radially toward the center and across the feature to look at what might be exposed. "If this feature is bowl-shaped, as the rover goes to the center, it will go higher and higher stratigraphically even though it's not going up in elevation," explained Banerdt. "That's one of the primary arguments for spending some time on top of Home Plate." There's no clear evidence of this stratification from MRO's HiRISE images. "But it could be there and just covered by surface dust," he suggested.

Posted by: BrianL Sep 6 2007, 05:26 PM

Have they said what it is about the SW corner that interests them? Is there a specific feature there that can be highlighted on the HiRISE shot?

Thanks
Brian

Posted by: Stu Sep 6 2007, 06:32 PM

Perhaps Stu feels a poem coming on.

Hmm, perhaps he does... wink.gif



SPIRIT PREVAILS…

I’ll admit there was a time back then –
when Sol’s golden light flickered and died –
that I thought Homeplate would be
my grave; as the sunlight faded
and my sight grew dim, a thin
and bony hand touched lightly on my beetle back
and turning I saw Death beside me,
smiling sadly as the salmon-tinted sky
was slowly fouled by clouds of swirling cinnamon
dust; rust-hued circuit-smothering fines
covered the Sun and plunged
me into Kuiperian gloom. Soon I shivered
in the frigid dark, sensing the spark
of my life sputtering, my heartflame guttering,
and weary beyond words I heard my Makers say
“Stay!” so I obeyed, and drove no more…

Sols passed, and like a dusty statue standing
on a plinth of sediment and stone I watched
the Sun phase in and out of view. Each new
sunrise shone fainter than the last; each brooding
sunset burned darker than the one that went
before and more than once I thought I felt
the breeze from death’s sharp and sweeping scythe –

- but I survived! and now the sky above grows bright
again, and even though dark dust has smothered me
and covers me, and my eyes are scratched and sore
I’ll tarry here no more. Not with fresh red rock to rove
and roam and rich lasagne-layers of ancient Gusev stone
to study and explore!

Homeplate’s mysteries and myths await –
and Man’s Spirit yearns to learn again…!

© Stuart Atkinson 2007

Posted by: Tesheiner Sep 6 2007, 08:55 PM

> Have they said what it is about the SW corner that interests them?

IIRC, at that corner is where they expect to find layers lower then at the NW one.

Stu, great words as usual.
Mmm, lasagne-layers?!?

Posted by: Tesheiner Sep 10 2007, 11:00 AM

Ah! Spirit finally did what I would call a drive; 11m during sol 1310 towards the SW corner.


Posted by: Stu Sep 11 2007, 10:51 AM

Top of HP with lots of rocks for Spirit to play with... tongue.gif


Posted by: Tesheiner Sep 11 2007, 12:29 PM

... and for the MER team to name after. tongue.gif

Gumbo and goulash are among them.

CODE
01310::p2587::18::3::0::0::3::1::7::pancam_gumbo_L257
01310::p2588::18::3::0::0::3::1::7::pancam_goulash_L257

Posted by: kenny Sep 11 2007, 01:52 PM

Gumbo and Goulash - they're now naming things for what comes in bowls ...

http://marsrovers.jpl.nasa.gov/mission/status.html

"Because Home Plate is bowl-shaped, scientists have decided to name features on top of Home Plate after things served in bowls. Stay tuned for upcoming yummy descriptions! "

Posted by: climber Sep 11 2007, 04:24 PM

QUOTE (kenny @ Sep 11 2007, 03:52 PM) *
"Because Home Plate is bowl-shaped, scientists have decided to name features on top of Home Plate after things served in bowls. Stay tuned for upcoming yummy descriptions! "

Don't forget "Cassoulet"...

Posted by: Juramike Sep 11 2007, 04:30 PM

Or "Cap'n Crunch"...

Posted by: vikingmars Sep 11 2007, 06:05 PM

QUOTE (climber @ Sep 11 2007, 06:24 PM) *
Don't forget "Cassoulet"...


laugh.gif ...and don't forget : "Choucroute" (Sauerkraut), "Couscous", "Tajine", "Potée aux Choux", "Raviolis", "Lasagnes", "Boeuf Bourguignon", "Blanquette de Veau"...
Just take a French Cuisine book and paste the names on the Mars rocks to save time...
And take this extra time for lunch or dinner to savour real cuisine with nice sauces in a French (or Italian) restaurant !

Posted by: Ant103 Sep 11 2007, 06:18 PM

Or "Ratatouille", "Bouillabaisse", "Ecorces vermeilles sauce Grand Veneur" (les carrotes rapées...)... In a plate who have the apparence of Home... Plate smile.gif biggrin.gif.

"-Mmmhh... french food...
- Homer!
- But Marge, I want to eat all!
- You are eating ALL at this moment!
- D'ohh!"

Posted by: ElkGroveDan Sep 11 2007, 06:26 PM

How about some American dishes? nachos, ravioli, chow mein biggrin.gif

Posted by: BrianL Sep 11 2007, 08:56 PM

C'mon it's the Red Planet, let's name something after a big bowl of Texas Red... Chili, that is.

Brian

Posted by: Phil Stooke Sep 11 2007, 09:05 PM

Me Mam used to put a bowl over my head and cut around it to give me a Beatles haircut. So I nominate "My Head"

Phil

(actually this is an outrageous lie)

Posted by: djellison Sep 11 2007, 10:11 PM

Olives, Peanuts, Phil's Head, Crisps, Soup, Ice Cream, and over at Meridiani..Berries smile.gif All things found in bowls.

Doug

Posted by: ngunn Sep 11 2007, 10:23 PM

The inner solar system has obviously turned quite nutty. I'm heading back out.

Posted by: Shaka Sep 11 2007, 10:33 PM

And for use in the New Year: Rose, Cotton, Sugar, Gator, Orange, Fiesta.... tongue.gif
...hmmm...or are we likely to have left HP by then? Somehow I doubt it.
We'll certainly be "in the ballpark".

Posted by: edstrick Sep 12 2007, 05:43 AM

Anyone for Ratatooie?

Posted by: Tesheiner Sep 12 2007, 01:25 PM

We have some fresh pics from sol 1312 and http://nasa.exploratorium.edu/mars/spirit/navcam/2007-09-12/ are the navcams for a full 360º mosaic.
It looks like this place is what's called "Site 2" on the http://marsrovers.jpl.nasa.gov/mission/status_spiritAll.html#sol1303.

QUOTE
On sol 1306 (Sept. 5, 2007), Spirit tried again and executed the drive flawlessly! Now that the rover's two rear wheels are on top of the eastern edge of Home Plate, Spirit is in position to explore the top of the elevated plateau along its eastern and southern edges. The next planned stop is a few meters away in an area known as "Site 2," located midway along the eastern scarp of Home Plate east scarp and several meters to the west of the scarp. (If you compared the roughly circular shape of the top of Home Plate to a clock, Site 2 would be at 3:30.)


Edited: Just for fun, this is an attempt to pinpoint Spirit's locations on a navcam mosaic from sol 1304.
(835k)

Posted by: dvandorn Sep 13 2007, 05:56 AM

Ooooh -- anyone else notice the arcuate and possibly pentagonal cracking in the upper surface of Home Plate in the latest images?

This used to be a cracked and tortured surface, it's been smoothed out over the megayears but it was as strong and tortured as any volcanic terrain we've ever seen on Earth.

-the other Doug

Posted by: dburt Sep 13 2007, 06:09 PM

QUOTE (dvandorn @ Sep 12 2007, 10:56 PM) *
Ooooh -- anyone else notice the arcuate and possibly pentagonal cracking in the upper surface of Home Plate in the latest images?

Yes, hard to miss. To me they look like they probably are bulk shrinkage cracks - typical of dessicated, originally damp surge deposits, which almost everyone agrees these seem to be. Such shrinkage cracks also appear typical of the layered, cross-bedded sediments at Meridiani, which may or may not also be surge deposits (depending on whose interpretation you favor).

HDP Don

Posted by: AlexBlackwell Sep 13 2007, 06:16 PM

QUOTE (dburt @ Sep 13 2007, 08:09 AM) *
Yes, hard to miss. To me they look like they probably are bulk shrinkage cracks - typical of dessicated, originally damp surge deposits, which almost everyone agrees these seem to be. Such shrinkage cracks also appear typical of the layered, cross-bedded sediments at Meridiani, which may or may not also be surge deposits (depending on whose interpretation you favor).

Which interpretation do you favor?

Posted by: dburt Sep 13 2007, 07:07 PM

QUOTE (AlexBlackwell @ Sep 13 2007, 11:16 AM) *
Which interpretation do you favor?

I like your style. laugh.gif More seriously, the simplest that accounts for all observations. Fortuitously, observations are still being made, and so I won't comment further.

- HDP Don

Posted by: helvick Sep 13 2007, 11:55 PM

Good to see you around HDP - I was worried that you had decided we had nothing left to offer. Looking forward to your take on the new stuff from both Home Plate and Victoria as it arrives.

Posted by: Tesheiner Sep 14 2007, 10:03 AM

Dear guests, the "menu" for sol 1315 is "http://en.wikipedia.org/wiki/Bouillabaisse".
Delicious!



tongue.gif

CODE
01315::p2590::18::4::0::0::4::2::10::pancam_bouillabaisse_L257R1

Posted by: jamescanvin Sep 14 2007, 10:20 AM

Sounds good. I wasn't so keen on tosols dish, I prefer mine unfractured!

CODE
01314::p2589::18::13::0::0::13::2::28::pancam_dumpling_fracture_L234567Rall

Posted by: Stu Sep 14 2007, 11:59 PM

Nice view from here...


Posted by: dvandorn Sep 15 2007, 05:52 AM

I'd like to see Spirit limp her way over to the fractures in the Plate that parallel its north-northwest edge. These cracks look constructional, not dessicational, to me. And where better to examine the history of the creation of this feature than along a constructional fracture?

I know I'm getting all excited about volcanic/basaltic rock emplacement, and Squyres et. al. are on record as not being all that interested in "ho-hum, another busted up hunk of lava." But for me, this is the kind of thing geology is all about -- reconstructing the events that caused such an unusual-looking but generically common (as there are certainly a number of similar features scattered throughout these hills) feature as Home Plate. I still don't think the possibility that this could have been part of an active hydrothermal system has yet been put to rest, since I know it had a great deal of support within the MER science team when Spirit first reached the Plate...

-the other Doug

Posted by: jvandriel Sep 15 2007, 03:05 PM

The 360 degree panoramic view taken on Sol 1312

with the R0 Navcam.

jvandriel

 

Posted by: jvandriel Sep 15 2007, 03:12 PM

and the view from 2 Sols earlier

Sol 1310 taken with the L7 Pancam.

jvandriel

 

Posted by: Phil Stooke Sep 16 2007, 12:45 PM

Here'a a polar version of Jvandriel's latest full panorama. It shows the little nearby craters quite well.

Phil


Posted by: OWW Sep 16 2007, 01:34 PM

Nothing from Spirit for two days now. I hope all is well... huh.gif

Posted by: djellison Sep 16 2007, 01:46 PM

M-ODY safe mode. Nothing to worry about. Not the first time it's happened, wont be the last - just one of those things.

Doug

Posted by: Jeff7 Sep 16 2007, 08:58 PM

I'd rather have lots of safe mode faults, than a robot that would just ignore them and keep plugging away, possibly putting itself at risk.smile.gif

Posted by: Tesheiner Sep 17 2007, 09:04 AM

> M-ODY safe mode. Nothing to worry about.

Just to recap what's the current situation re. both rovers.

Spirit: latest data/images dowlinked are from sol 1314. We are currently on sol 1317 and Spirit was supposed to leave the "site 2" on sol 1315.
Opportunity: latest data are from sol 1293. Currently on sol 1297 and was planned to continue moving downslope yestersol (1296).

Posted by: fredk Sep 18 2007, 04:06 PM

New http://marsrovers.jpl.nasa.gov/mission/status_spiritAll.html#sol1309 This one talked about a fracture (that has been mentioned before):

QUOTE
... Spirit began driving across the top of the elevated plateau, en route to taking more images and examining a possible fracture in the bedrock.
And
QUOTE
Sol 1314 (Sept. 13, 2007): Spirit acquired full-color views, using all 13 filters of the panoramic camera, of the fracture on Home Plate.
All of the 1314 pancam imagery is not down yet, but can we guess what feature they are talking about? Could it be the dark gash running left to right, just above mid height on http://marsrovers.jpl.nasa.gov/gallery/all/2/p/1314/2P243019214EFFAV00P2390R1M1.JPG

Posted by: climber Sep 18 2007, 04:30 PM

QUOTE (fredk @ Sep 18 2007, 06:06 PM) *
http://marsrovers.jpl.nasa.gov/gallery/all/2/p/1314/2P243019214EFFAV00P2390R1M1.JPG

Slightly OT, is that Gusev's walls we can see on this picture ? If yes, the Tau must have improved a lot.

Posted by: Tesheiner Sep 18 2007, 04:37 PM

Fredk, digging on the pancam web I found this:

CODE
01314::p2388::18::24::0::0::24::2::50::pancam_fracture_4x1_L257R127


And here are the 64x64 thumbnails (L2 filter) corresponding to the "fracture".

Posted by: Floyd Sep 18 2007, 04:40 PM

fredk: I think you can see a nice fracture in Home Plate in Tesheiner maps. It goes for 7 to 9 o'clock.


QUOTE (Tesheiner @ Sep 10 2007, 08:14 AM) *
Spirit route map, updated to sol 1310.
[attachment=11709:attachment]



I think the part you see across a gap is a ridge, also seen just to the southeast of home plate.

Posted by: jamescanvin Sep 18 2007, 04:44 PM

Ah but Tesh, the update Fredk quoted talked about a full 13 filter image being taken so it must be the 'dumpling_fracture' which is pointed near the bottom centre of http://qt.exploratorium.edu/mars/spirit/navcam/2007-09-12/2N242845711EFFAV00P1962R0M1.JPG

James

Posted by: fredk Sep 18 2007, 05:42 PM

Thanks for the responses. It seems like those thumbnails and the image refered to by James may all lie along the same long fracture. The thumbnails start near the bottom of http://marsrovers.jpl.nasa.gov/gallery/all/2/n/1312/2N242845813EFFAV00P1962R0M1.JPG, which is just west of the frame James pointed to, and the thumbnails continue across http://marsrovers.jpl.nasa.gov/gallery/all/2/n/1312/2N242845848EFFAV00P1962R0M1.JPG diagonally from the lower left towards the upper right. I can imagine a corresponding dark linear feature in that last navcam.

I think I've spotted it in the Hirise image. In Tesheiner's route map, you can see a fairly broad dark feature working its way from just left of the words "Home Plate", to just under those words, and then towards Spirit's current location (somewhat south of the 1310 location). (Sorry, I haven't been able to upload attatchments with the new forum software so I can't sketch it out.)

Posted by: fredk Sep 18 2007, 05:54 PM

QUOTE (climber @ Sep 18 2007, 04:30 PM) *
Slightly OT, is that Gusev's walls we can see on this picture ? If yes, the Tau must have improved a lot.
The jagged hills we see on the horizon in that frame are not the rim of Gusev, but some much more nearby hills and the rim of the large "mudspat" crater (I don't remember names). These features are now visible more clearly than the worst of the storm. I suspect it'll be quite a while before we see the rim of Gusev.

Posted by: CosmicRocker Sep 18 2007, 06:41 PM

I'm fairly confident that this fracture is the same one that was evident in http://marsrovers.jpl.nasa.gov/gallery/all/2/n/1116/2N225441266EFFASR6P0786L0M1.HTML. See also http://marsrovers.jpl.nasa.gov/gallery/all/2/p/1121/2P225882648EFFASSJP2430L7M1.HTML It corresponds to the NW/SE trending fracture apparent on the HiRise image.

Posted by: dvandorn Sep 19 2007, 06:33 AM

I took a good look at the initial HiRISE image of Home Plate, and I see a lot of interesting fractures on this feature:



I apologize for the crude image tools. The red lines follow a number of what appear to me to be fractures. Some of them look like they could be remnants of crater rims, but most (especially those along the left edge of HP, as seen in this image) appear to be constructional fractures.

Some may well be dessicational -- but most, especially those near the perimeter of HP, look constructional to me.

-the other Doug

Posted by: fredk Sep 20 2007, 02:45 AM

From http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20070919a.html

QUOTE
If you were going to look for past water on Mars, there are three good ways: 1) Look for salts left behind from salty water that evaporated; 2) Look for soft, muddy soil frozen in place over time; and, 3) look for signs of volcanic explosions where water contacted hot, molten rock. At "Home Plate" on Mars, scientists have found all three.
What do you guys think they are referring to by "soft, muddy soil frozen in place over time"? Can you point to this in images?

Posted by: CosmicRocker Sep 20 2007, 03:54 AM

That one has me guessing, too. My best guess as to what they are referring to is the sedimentary structure that was called a "http://marsrovers.nasa.gov/gallery/press/spirit/20070503a/Figure_3_br.jpg," which was observed when they first drove up to HP and imaged its lower section. That observation supports both #2 and #3. wink.gif

Posted by: Floyd Sep 20 2007, 11:28 AM

Maybe they are refering to all of Home Plate

Posted by: Tesheiner Sep 20 2007, 01:51 PM

After this hiatus due to ODY safe-mode, we finally have some new images from Spirit.
These ones correspond to sol 1315 when Spirit left the "Site 2".

http://nasa.exploratorium.edu/mars/spirit/navcam/2007-09-20/

Posted by: fredk Sep 20 2007, 03:41 PM

QUOTE (CosmicRocker @ Sep 20 2007, 03:54 AM) *
My best guess as to what they are referring to is the sedimentary structure that was called a "http://marsrovers.nasa.gov/gallery/press/spirit/20070503a/Figure_3_br.jpg,"...
Yeah, that's probably a good bet. Still, they used the word "muddy". Do the geologists here know if the bomb sag needed to be in "muddy" soil? Could it just have been soft ash?

Posted by: ElkGroveDan Sep 20 2007, 04:15 PM

QUOTE (fredk @ Sep 20 2007, 07:41 AM) *
Do the geologists here know if the bomb sag needed to be in "muddy" soil? Could it just have been soft ash?

I'm guessing nothing as soft as fresh ash. If that was the case it would have punched a straight column. This one however has deformed the layer it is resting on without actually crossing through it. So it must have been a soft substance that still retained it's cohesiveness, possibly a damp mud composed of older compacted ash.

 

Posted by: dburt Sep 20 2007, 09:08 PM

QUOTE (ElkGroveDan @ Sep 20 2007, 09:15 AM) *
I'm guessing nothing as soft as fresh ash. If that was the case it would have punched a straight column. This one however has deformed the layer it is resting on without actually crossing through it. So it must have been a soft substance that still retained it's cohesiveness, possibly a damp mud composed of older compacted ash.

I would agree completely. Bomb sags in basaltic surge deposits, which Home Plate is presumed to consist of, can be abundant near the vent (crater). The fine surge deposits are deposited as steam in the surge cloud condenses, forming damp deposits that mainly consist of reworked older material ejected explosively from the vicinity of the crater, or scoured by the radial flow of the cloud, and incorporated in the turbulent, rapidly-flowing, ground-hugging mixture. In the midst of this process, coarser ejecta (quenched lava or solid rock "bombs") can "rain out" ballistically from steam explosions at the vent, forming "bomb sags". Additional fine-grained damp surge deposits are then deposited on top of the sag.

The main problem I have with this "volcanic" scenario for Home Plate is that so far no volcanic vent area (crater) or other direct evidence of volcanism (e.g., a lava flow, a recognizable teardrop-shaped "bomb") is evident in the vicinity; another is that, so far, there is only the single putative bomb sag in evidence. That is the basis for our suggestion that the cross-bedded Home Plate deposits, like the very similar-appearing Meridiani deposits, could have been deposited from much larger turbulent, steamy surge clouds resulting from distant meteorite impacts into ice- and/or brine-rich basaltic regolith. Ballistic ejecta resulting from such impacts are certainly at least as well documented as volcanic "bombs" next to a vent.

BTW, the ferric acid sulfates that occur as local efflorescences (colorful crusts) just below the Gusev surface are hardly typical evaporite deposits. They also indicate dampness, but probably not liquid water. To us they might indicate damp oxidative weathering of broken iron sulfides, as on an Arizona mine dump, although they might also form by direct reaction inside the steamy surge cloud. So far, they do not appear to represent localized hot springs or steamy fumaroles, because there is no obvious localized alteration of the rocks around them. The fragmental silica-rich deposits likewise do not appear to have formed "in place" because they seem to sit on top of older, unaltered underlying deposits, just like the angular broken rocks that cover the surface of Home Plate itself.

Just restating our generalized "impact-centric" hypothesis, that still disagrees in large part with the official "Earth-centric" interpretations. I do so merely as a possible guide to further exploration. I don't want to rehash all the arguments from that old thread of several months ago, or get into new ones with the same people.

--HDP Don

Posted by: helvick Sep 20 2007, 11:53 PM

Refreshing input DB (as ever) and thanks for adding an consistent explanation for the localised concentrations of highly sorted interesting near sub surface materials ( the efflorescenses ) - these have bothered me for a while and it's nice to see that you have them in your sights. To date I haven't seen any good explanation of the Tyrone class material deposits.

Posted by: Aussie Sep 21 2007, 03:33 AM

QUOTE (fredk @ Sep 20 2007, 02:45 AM) *
From http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20070919a.htmlWhat do you guys think they are referring to by "soft, muddy soil frozen in place over time"? Can you point to this in images?


Fred, the JPL comment at your link actually states 'Look for rocks that show evidence of being originally laid down wet'. Did they amend this image comment from "soft, muddy soil frozen in place over time"?

The Home Plate region is fascinating, but I think I would like to sit on the fence as regards its genesis until the analysis of Innocent Bystander is available. Even then, is there any reason why both volvanic and impact surge/deposition could not have influenced the area?

Posted by: CosmicRocker Sep 21 2007, 04:38 AM

Hmm... It seems that they would prefer to be less specific about that. wink.gif That's interesting. I am guessing the original "frozen in place over time" comment might have referred to mineralization in place, rather than the actual phase-change freezing in place of saturated sediments.

Posted by: Julius Sep 21 2007, 11:26 AM

The more I follow Mars,the more it becomes obvious that the water theory somehow is losing ground.Gullies as seen by Hirise seem to show landslide deposits and not necessarily caused by water!The Home plate deposits seem to be related to some form of volcanic activity!The frozen sea seen in 2005 seems to have been identified as a pond of lava! At this point,I would have to start to reconsider the true origin of the meridiani rocks.

Posted by: marsbug Sep 21 2007, 01:22 PM

I don't think there's much of a 'somehow' about it julius, an icy mars warmed very occasionally by impacts or volcanism has seemed a likely scenario for a while now. I wouldnt ever count liquid water out of the equation entirely though, theres so much ice on mars that even if conditions were right for melting only occasionally and briefly it could make an impact on martian geology and history.

Posted by: fredk Sep 21 2007, 04:13 PM

QUOTE (Aussie @ Sep 21 2007, 03:33 AM) *
Fred, the JPL comment at your link actually states 'Look for rocks that show evidence of being originally laid down wet'. Did they amend this image comment from "soft, muddy soil frozen in place over time"?
Wow! That caption had an unusually casual feel about it, and clearly the original line we commented on was particularly problematic. I just wonder if someone over there read us over here...

So I suppose the new point #2 could still apply to the bomb sag?

Posted by: tty Sep 21 2007, 07:29 PM

It seems highly unlikely that "brief and occasional" melting could create the Eberswalde delta for example.

Posted by: dburt Sep 21 2007, 09:05 PM

QUOTE (Aussie @ Sep 20 2007, 08:33 PM) *
... is there any reason why both volcanic and impact surge/deposition could not have influenced the area?

Good point. By our hypothesis, the fragmental basaltic lava and ashy-looking rocks, including those of Home Plate itself, and the silica-rich rocks on the surface could have formed via conventional volcanism, and volcano-related hydrothermal (hot springs) activity respectively, but somewhere else on Mars (perhaps far, perhaps near). Then later impact into these frozen/briny/salty deposits (by then buried) placed them where we see them now, as both coarse angular impact breccias and as finely-layered impact surge deposits. Another distinct possibility is that they were totally formed by impact - that the lava-like rocks, especially the highly vesicular (bubbly) ones, represent reworked (via later impacts) impact melts from a large crater (such as Gusev itself, later filled with freezing brine), and that the reworked silica-rich deposits formed as the result of impact-related hydrothermal activity near that or another large crater. This might be stretching the impact scenario a bit more than needed, though - Mars certainly has abundant volcanic rocks, and probably had related hot springs, and impacts can transport both rocks and fine materials for great distances.

-- HDP Don

Posted by: marsbug Sep 21 2007, 09:15 PM

QUOTE (tty @ Sep 21 2007, 08:29 PM) *
It seems highly unlikely that "brief and occasional" melting could create the Eberswalde delta for example.

No argument there! hence the 'even if'.

Posted by: dburt Sep 21 2007, 09:29 PM

QUOTE (tty @ Sep 21 2007, 12:29 PM) *
It seems highly unlikely that "brief and occasional" melting could create the Eberswalde delta for example.

Remember that to a geologist "brief and occasional" could refer to a circumstance that was many thousands or tens of thousands of years in duration (as compared to many billions of years for the more normal circumstance). For example, ice ages in Earth history (including the icy period that currently seems to be ending rather too abruptly) could be thought of as "brief and occasional" in frequency and duration.

-- HDP Don

Posted by: Aussie Sep 22 2007, 02:11 AM

Don,
A bit of a stretch I know, but is there not a possibility that major impact events could have been the trigger for massive volcanic activity, both in the area surrounding impacts and also at the seismic focus at the other side of the martian sphere. For example the major vocanic phenomona such as Olympus Mons seem to be pretty much opposite the Helles Depression, an impact which would have created the mother of all siesmic events.

Posted by: dvandorn Sep 22 2007, 04:30 AM

I just can't reconcile the huge outflow channels (where, I will point out, two of the five successful landers have touched down), the obvious water-carved channels and riverbeds, and the north-south dichotomy with a Mars that has almost never seen liquid water flowing on its surface.

It might not have been wet there for three and a half billion years, but *massive* amounts of liquid water once flowed on Mars. The morphological evidence is overwhelming. Those who continue to try and find alternatives serve a useful purpose, but it's time that we actually accept the evidence of our eyes and spend our energy constraining the time frames during which Mars was wet, and stop denying that it ever happened.

IMHO.

-the other Doug

Posted by: edstrick Sep 22 2007, 08:35 AM

I haven't had time yet (this weekend...) to read the press release and a few reports, like on space.com, on the mars-water business, but my take is that they're starting to de-hype the press-office and media exaggerated speculations that we're seeing or likely to see active water-caused surface changes in current data. Which is not to argue that plausibly water carved <or carving-aided> features were not water-involved, but that it's not as likely as we've been starting to think that it's happening THIS YEAR, as opposed to sometime in the last obliquity cycle.

Posted by: jvandriel Sep 22 2007, 05:08 PM

The panoramic view taken on Sol 1315

with the R1 pancam.

jvandriel


 

Posted by: Bill Harris Sep 22 2007, 08:58 PM

QUOTE
It might not have been wet there for three and a half billion years, but *massive* amounts of liquid water once flowed on Mars. The morphological evidence is overwhelming...
I'll have to agree with Doug on this. Water has flowed and flowed abundantly in the past. The morphological evidence is overwhelming.

--Bill

Posted by: dvandorn Sep 23 2007, 05:45 AM

That's why I have such a hard time understanding the gut reaction a handful of planetary scientists seem to have at this apparent fact. Their reaction, instead of trying to constrain the time frames, the extent of standing water, the processes by which that water has been buried or trapped at the poles or sputtered way into the void, etc., etc., seems to be: "Well, wait -- there *must* be another explanation for this. There simply must. Let's see how many improbable theories we can generate to explain this, since it simply *cannot* be liquid water which made these landforms. Utterly impossible."

Every theory I hear, from "White Mars" to "insignificant capillary action and frosts", tries to explain away one tiny fragment of a growing body of overwhelming evidence, first and foremost of which is the morphological evidence. Yes, capillary action involving tiny amounts of water could have produced some of the alteration we've seen in rocks at Gusev -- but it doesn't explain the massive outflow channels. Yes, dry ice phase change physics can explain some aspects of some erosional features -- but it does not explain the meandering river valleys. And so on, and so on. The whole approach begs Occam's Razor to cease to exist -- it's like they want to abandon the obvious, simplest, most probable answer in favor of *anything* else.

It's like standing in the middle of the American southwest, pulling up abundant marine fossils from the ground, and spending the rest of your life feverishly trying to convince everyone that they must have somehow been transported there from some currently existing ocean. That the American southwest could *never* have been a seafloor, for the simple reason that it isn't one now.

Mars may have been like it is now, more or less, for a long time. But it was, for some period of time, a lot different. It's time to accept that and not feverishly argue that it couldn't have been...

-the other Doug

Posted by: Bill Harris Sep 23 2007, 11:26 AM

Doug--

With so many landforms that look "aqueous" that aren't, that I think that the tendency early on was to err on the side of caution. In other words, making sure that the duck sound you heard was actually a duck. But we have sufficient evidence that the paleoenvironment of Mars was soggy.

--Bill

Posted by: Tesheiner Sep 23 2007, 09:44 PM

LOTS of layering around the current position.
Spirit, the five-leg dog, did a quite long move on sol 1323; around 20m! Which was the last time she did such a thing?


Posted by: djellison Sep 23 2007, 09:46 PM

QUOTE (Tesheiner @ Sep 23 2007, 10:44 PM) *
Which was the last time she did such a thing?


Not quite sure - but Spirit was steam-powered at the time, and everything was in black and white...and worked in a coal mine.

Doug

Posted by: ElkGroveDan Sep 23 2007, 10:22 PM

QUOTE (Bill Harris @ Sep 23 2007, 03:26 AM) *
making sure that the duck sound you heard was actually a duck.

That's over in Meridiani, Bill

(Sorry can't find the picture right now)

Posted by: fredk Sep 23 2007, 11:23 PM

QUOTE (dvandorn @ Sep 23 2007, 05:45 AM) *
Their reaction... seems to be: "Well, wait -- there *must* be another explanation for this. There simply must. Let's see how many improbable theories we can generate to explain this, since it simply *cannot* be liquid water which made these landforms. Utterly impossible."
Unfortunately, or fortunately, that seems to describe exactly what happens in many branches of science. In cosmology, for example, we have people arguing that dark matter doesn't exist and that its apparent effects are due to modifications to gravity. Opponents (the majority) say those modifications are contrived and that the evidence for dark matter is overwhelming. In the end consensus will be reached, and in those rare cases that the majority had it wrong they'll be set on the right track. Before everyone's finally on board it unfortunately can be a bit subjective to decide if it's worthwhile pursuing alternative views.

Posted by: fredk Sep 23 2007, 11:29 PM

QUOTE (ElkGroveDan @ Sep 23 2007, 10:22 PM) *
That's over in Meridiani, Bill

(Sorry can't find the picture right now)
I think the picture might be in http://www.unmannedspaceflight.com/index.php?s=&showtopic=3749&view=findpost&p=80529

Posted by: ElkGroveDan Sep 24 2007, 05:06 AM

QUOTE (fredk @ Sep 23 2007, 03:29 PM) *
I think the picture might be in http://www.unmannedspaceflight.com/index.php?s=&showtopic=3749&view=findpost&p=80529

Thanks Fred. I don't know how you guys keep track of all these. I never would have found that on my own.

Posted by: dburt Sep 24 2007, 09:30 PM

QUOTE (Aussie @ Sep 21 2007, 07:11 PM) *
Don,
A bit of a stretch I know, but is there not a possibility that major impact events could have been the trigger for massive volcanic activity, both in the area surrounding impacts and also at the seismic focus at the other side of the martian sphere. For example the major vocanic phenomena such as Olympus Mons seem to be pretty much opposite the Helles Depression, an impact which would have created the mother of all siesmic events.

Aussie - Without looking up the many references, such effects have been seriously suggested, for both the Earth (e.g., Sudbury, Canada, local) and Mars (e.g., Hellas, w.r.t. Tharsis volcanism on the opposite side), but cause-and-effect relations can be difficult to prove. For example, people still argue as to whether or not the "Sudbury Intrusive" represents impact melt, although most now accept that the "Onaping tuff" represents impact debris.

BTW, regarding the weekend discussion of water and ducks, you can probably make early Mars as wet as you want - just don't make it too hot (except for transient impact or volcanic heating, or local solar heating of dark rocks on the surface). Climate variation may have been more extreme than on Earth, but probably alternated between cold and colder. In this regard, not enough liquid water to attract ducks at either Home Plate or Meridiani, IMHO, although both were probably damp owing to steam condensation. smile.gif I see no problem with liquid water condensates making drainage networks after huge ancient impacts or with local brine break-outs making transient outflow channels later, but only as special events. Ice was probably more normal near the surface.

-- HDP Don

Posted by: Stu Sep 24 2007, 10:50 PM

Quick colourised Pancam panorama...



Posted by: marsbug Sep 25 2007, 10:57 AM

QUOTE (dburt @ Sep 24 2007, 10:30 PM) *
Ice was probably more normal near the surface.
-- HDP Don

Ice above -20 often contains veins of liquid water kept liquid by impurities, this is the first stage of Dburts eutectic brine formation. If a piece of dark coloured rock is included in a piece of ice near the surface then sunlight will warm the rock, which will lead to these veins becoming larger and more numerous near the rocks surface. Many people here probably know this already, but if surface ice was present at home plate or meridiani in the past could this provide a source of rock altering 'dampness'? Wouldn't steam condensing onto a rock surface form ice (not right away perhaps but fairly quickly) at martian temperatures anyway? If this has already been discussed could someone point me in the right direction?

Posted by: jvandriel Sep 25 2007, 06:44 PM

Here is the complete 360 degree panoramic view taken with the

L0 Navcam on Sol 1315,1316 and Sol 1317.

jvandriel


Posted by: dburt Sep 25 2007, 07:38 PM

QUOTE (marsbug @ Sep 25 2007, 03:57 AM) *
Ice above -20 often contains veins of liquid water kept liquid by impurities, this is the first stage of Dburts eutectic brine formation. If a piece of dark coloured rock is included in a piece of ice near the surface then sunlight will warm the rock, which will lead to these veins becoming larger and more numerous near the rocks surface. Many people here probably know this already, but if surface ice was present at home plate or meridiani in the past could this provide a source of rock altering 'dampness'? Wouldn't steam condensing onto a rock surface form ice (not right away perhaps but fairly quickly) at martian temperatures anyway? If this has already been discussed could someone point me in the right direction?

Thanks for the citation. Actually, if there is Ca in the brine (because CaCl2 brine is extremely hard to freeze, and Ca will be concentrated by ice freezing), last or eutectic freezing won't occur until below -50 C (close to avg. near-surface temperature for Mars). Steam condensing at low modern martian pressures (above the triple point of water, at least for higher elevations), can only condense into ice (frost, snow), unless salts are present at the surface of condensation, which could yield a brine film (i.e., dampness). Ancient Mars probably had higher atmospheric pressures, so salts might not have been needed to yield a condensate of liquid water (or dampness). In any case, preferential post depositional leaching of recrystallized chloride salts by frost or ice could account for the crystal-shaped cavities, and other porosity, seen in the bedded rocks, particularly at Meridiani. Sulfate salts would tend not to be leached by frost, inasmuch as none exhibit freezing point depressions greater than -5 C. Frost leaching of common chloride salts (with F.P. depressions of 20 to 50 C) might also account for the report that chloride content, unlike sulfate content, increased with depth at Meridiani. More than you wanted to know?

-- HDP Don

Posted by: djellison Sep 25 2007, 07:40 PM

NICE stitch. I did a polar-and-pinch with it.

 

Posted by: marsbug Sep 26 2007, 11:19 AM

QUOTE (dburt @ Sep 25 2007, 08:38 PM) *
More than you wanted to know?

-- HDP Don


A bit more than I was expecting but I've no complaint! However it would help my understanding a lot if you could point me in the direction of a detailed explanation of frost leaching, as I've got only a vague idea of how it works and hence only a very vauge understanding of your reply! smile.gif

Edit: I've no wish to turn this thread into an undergraduate geology classroom, but my usual sources (wikipadea and google) have let me down a bit on this one.

Posted by: dburt Sep 26 2007, 06:50 PM

QUOTE (marsbug @ Sep 26 2007, 04:19 AM) *
It would help my understanding a lot if you could point me in the direction of a detailed explanation of frost leaching, as I've got only a vague idea of how it works and hence only a very vague understanding of your reply! smile.gif

Marsbug - I'm pretty sure it doesn't belong in this thread, but the concept is pretty simple. When salt is scattered on winter snow or ice, the desired result is to melt the ice, but this imples dissolution (leaching) of the salt too - and that's what we're talking about here. Picture soluble salt crystals scattered on the surface of a road or sidewalk in the winter. If it rains, they'll be leached (dissolved). If it snows or frost condenses, they'll only be leached if the temperature is above their maximum freezing point depression (so-called eutectic temperature with ice). Because the freezing point of pure ice is 0 degrees C, that means that sulfate salts can only be "frost leached" above about - 5 degrees C or less, whereas NaCl salt (halite or table salt) can be frost leached if the temperature is above - 21 degrees C, and CaCl2 salt (used by more affluent or northern communities) if the temperature is above -50 degrees C. Is that clearer?

As regards Mars, various salts were scattered across the surface by impacts (and wind). Billions of years of frost condensation should have preferentially leached the chlorides (especially calcium chloride) into subsurface brines, but left the sulfates at the surface, simply because Mars is so cold. See the Knauth/Burt papers from 2002 and 2003 for more detail.

-- HDP Don

Posted by: fredk Sep 28 2007, 03:56 AM

I haven't noticed dust devils in images for a while, but there is still activity, as you can see by the changes around El Dorado in these navcams, sols 1315 and 1325:
http://marsrovers.jpl.nasa.gov/gallery/all/2/n/1315/2N243112838EFFAV37P0746R0M1.JPG
http://marsrovers.jpl.nasa.gov/gallery/all/2/n/1325/2N243994768EFFAVAQP1977R0M1.JPG

and these hazcams, 1323 and 1326:
http://marsrovers.jpl.nasa.gov/gallery/all/2/f/1323/2F243822120EFFAVAQP1214L0M1.JPG
http://marsrovers.jpl.nasa.gov/gallery/all/2/f/1326/2F244083694EFFAVAQP1155L0M1.JPG

Posted by: Stu Sep 28 2007, 05:47 AM

Anyone got any idea if Spirit is anywhere near the rock christened 'Mckay' again? I'd love some really detailed close-ups of that one...


Posted by: jamescanvin Sep 28 2007, 09:08 AM

If you look at the route map Stu you'll see we're right over the other side of HP from Mackey at the moment.

James

Posted by: Tesheiner Sep 28 2007, 09:45 AM

AFAIK this 360º panorama wasn't posted yet.
It was taken on sols 1323 and 1325 and corresponds to the current site, referred as "Texas Chili" on the http://marsrovers.jpl.nasa.gov/mission/status_spiritAll.html#sol1321.



BTW, Spirit is in the middle of taking a multi-sol color mosaic of this same area.
CODE
01325::p2279::07::24::0::0::24::2::50::pancam_homeplate_site3_3cx2r_L257R1
01326::p2280::07::16::0::0::16::2::34::pancam_homeplate_site3_2cx2r_L257R1
01327::p2281::07::16::0::0::16::2::34::pancam_homeplate_site3_2cx2r_L257R1
01327::p2282::07::16::0::0::16::2::34::pancam_homeplate_site3_2cx2r_L257R1
01328::p2283::07::24::0::0::24::2::50::pancam_homeplate_site3_3x2_L257R1
01329::p2284::07::16::0::0::16::2::34::pancam_homeplate_site3_2x2_L257R1

Posted by: kungpostyle Sep 28 2007, 06:27 PM

I noticed a couple of items in a recent pancam image:

[source image at]

http://qt.exploratorium.edu/mars/spirit/pancam/2007-09-27/2P243992544EFFAVAQP2279L7M1.JPG



The upper item may just be resting there with dust around it, but the lower one looks like a blue berry to me.

Posted by: Phil Stooke Sep 28 2007, 07:34 PM

Here is TEsheiner's latest pan in polar format.

Phil


Posted by: dburt Sep 28 2007, 08:55 PM

QUOTE (kungpostyle @ Sep 28 2007, 11:27 AM) *
I noticed a couple of items in a recent pancam image:
...
The upper item may just be resting there with dust around it, but the lower one looks like a blue berry to me.

Really hard to say. That's the frustrating thing about many Mars images, including close-ups from the Pancams. You can see practically anything you're looking for. If that object were part of a collection of blueberries, you might expect to see some lying around on the surface, as a Meridiani-style lag deposit, and that confirmation seems to be lacking in that image. Now tell me what we're seeing in this Pancam image, also from today, in the lower left half. Is it dozens of blueberries, somehow concentrated on the eroding edges of bedding planes, and as a lag on the ground, or something altogether different? I have no idea, but somehow suspect (it's the innate pessimist in me) that we're not looking at blueberries:
http://qt.exploratorium.edu/mars/spirit/pancam/2007-09-28/2P244254065EFFAVAQP2283R1M1.JPG

Of course, the even more frustrating thing about Mars images is that we can't all get to drive the rover to check such features out. laugh.gif

--HDP Don

Posted by: kungpostyle Sep 28 2007, 11:37 PM

QUOTE (dburt @ Sep 28 2007, 04:55 PM) *
You can see practically anything you're looking for.


Good point, I have to admit I was looking for bomb sag when I saw those (though I don't expect it on top of home plate). It is hard to be impartial!

-Kung

Posted by: climber Sep 29 2007, 06:52 AM

If my maths are correct, today, Spirit complete her second year on Mars.
smile.gif

Posted by: alan Sep 29 2007, 03:23 PM

QUOTE (climber @ Sep 29 2007, 01:52 AM) *
If my maths are correct

I got 1338 (1+ 2*668.5991=1338.1982) for the second anniversary, tosol is 1329.
http://en.wikipedia.org/wiki/Timekeeping_on_Mars
What source are you using for the number of sols in a year?

Posted by: alan Sep 30 2007, 07:52 PM

Spirit's planned winter haven is mentioned in latest Planetary society MER update:

QUOTE
the current hope, said Squyres, "is that we will finish up at Home Plate and move in a sprightly fashion to the von Braun-Goddard regions with the intention of somewhere in there being our winter over spot."
http://www.planetary.org/news/2007/0930_Mars_Exploration_Rovers_Update_Spirit.html

I assume Goddard is the the 'crater' on the east side of Von Braun

Posted by: fredk Oct 1 2007, 12:13 AM

Yep, that's Goddard: http://mars.jpl.nasa.gov/mro/gallery/press/20061213a/PIA09088-RA2-hirise-context_annotated_br.jpg

That's a pretty exciting plan for Spirit's future. I've been very eager to get a close look at Von Braun and Goddard. The distance isn't bad at all, considering our last drive, but let's hope the surface is traversable and not a big sand trap.

Posted by: Stu Oct 1 2007, 11:51 AM

LOVE it when Spirit shows us the jagged rocks on the side of the hills...


Posted by: Ant103 Oct 2 2007, 08:57 AM

Love when Stu post lovely pictures of rocks on the side of the hills.

Posted by: hortonheardawho Oct 2 2007, 09:07 PM

Spirit sol 1330 colorized MI panorama of "Texas Chili":

http://www.flickr.com/photos/hortonheardawho/1469378476/

with links to location and original panorama which has links to 3D pairs.

Posted by: Shaka Oct 2 2007, 10:14 PM

QUOTE (hortonheardawho @ Oct 2 2007, 11:07 AM) *
Spirit sol 1330 colorized MI panorama of "Texas Chili":

Hot diggity! And what are the little red blotches? Chili peppers? Paprika? cool.gif

Posted by: hortonheardawho Oct 2 2007, 11:18 PM

QUOTE (Shaka @ Oct 2 2007, 06:14 PM) *
Hot diggity! And what are the little red blotches? Chili peppers? Paprika? cool.gif


Er, the red spots are most likely imaging artifacts caused by interpolation and registration of a tiny piece of a pancam image with a MI panorama.

But there is a small quantum mechanical like probability that it is chili pepper flakes -- freeze dried.

The image colors are only a hint of what might be.

Posted by: fredk Oct 3 2007, 04:51 AM

Some new marks are visible on Spirit's panels in the new navcams. Look especially near the bottom of this frame:
http://marsrovers.jpl.nasa.gov/gallery/all/2/n/1331/2N244526560EFFAVAQP0516R0M1.JPG

Compare with this frame from sol 1221:
http://marsrovers.jpl.nasa.gov/gallery/all/2/n/1221/2N234768453EFFATI4P0165R0M1.JPG

Perhaps this happened during the dust storm?

Posted by: Tesheiner Oct 3 2007, 09:57 AM

Spirit moved south to a new site during sol 1332 and here are the latest navcams.
http://qt.exploratorium.edu/mars/spirit/navcam/2007-10-03/

Once again, lots of layering around. cool.gif

Posted by: Stu Oct 3 2007, 03:45 PM

... lots more detail visible on them thar hills on the horizon too... air must be a lot clearer at last...


Posted by: Marz Oct 4 2007, 04:23 PM

QUOTE (fredk @ Oct 2 2007, 11:51 PM) *
Some new marks are visible on Spirit's panels in the new navcams. Look especially near the bottom of this frame:
http://marsrovers.jpl.nasa.gov/gallery/all/2/n/1331/2N244526560EFFAVAQP0516R0M1.JPG

Compare with this frame from sol 1221:
http://marsrovers.jpl.nasa.gov/gallery/all/2/n/1221/2N234768453EFFATI4P0165R0M1.JPG

Perhaps this happened during the dust storm?


Yikes! Are those clumps of dust that aggregated during the Storm, or are they something more heinous? My kingdom for a DustBuster™!

Posted by: jvandriel Oct 4 2007, 06:36 PM

A panoramic view taken on Sol 1323, Sol 1325 and Sol 1331

with the R0 Navcam.

jvandriel


Posted by: ustrax Oct 4 2007, 06:55 PM

QUOTE (jvandriel @ Oct 4 2007, 07:36 PM) *
A panoramic view taken on Sol 1323, Sol 1325 and Sol 1331


Man! I believe I've never given thanks for your work that always allow us to enjoy the whole context...
Thank you very much!
Look how dark El Dorado looks...are the abyss gates open?... tongue.gif

Posted by: jvandriel Oct 4 2007, 07:33 PM

Thanks Ustrax,

and special for you ( and of course for all the other members and viewers )

here is the view taken on Sol 1332 with the R0 Navcam.

jvandriel


Posted by: jvandriel Oct 4 2007, 07:58 PM

and the view in the same direction but now taken with

the R1 Pancam on Sol 1332 and colourized.

jvandriel


Posted by: jvandriel Oct 6 2007, 09:03 AM

A view of the Solar Deck of Spirit with some dust particles.

Taken with the R0 Navcam on Sol 1332.

jvandriel


Posted by: n1ckdrake Oct 6 2007, 10:37 AM

Great work jvandriel!

Posted by: Space Oct 7 2007, 08:45 AM

Hello!
My first panorama :
http://www.enregistrersous.com/images/43057009420071006125201.jpg

Posted by: Stu Oct 7 2007, 08:55 AM

Nice one Space smile.gif

Welcome to UMSF!

Posted by: mhoward Oct 8 2007, 03:51 AM

Here's an http://www.youtube.com/watch?v=uoOKuDAC0OI.

Posted by: tdemko Oct 8 2007, 11:50 AM

Great place for the clastic sedimentologists! This is the best view, so far, of a number of stacked trough crossbed sets, showing nice tangential toesets and truncation surfaces. You also get a good sense of the unidirectional nature of the transport direction (successive sets are all dipping the same direction). Still looks like an eolian deposit to me.

http://qt.exploratorium.edu/mars/spirit/navcam/2007-10-07/2N245061747EFFAVFUP0716R0M1.JPG

One aspect of Home Plate region that still bugs me is the current structural geology...this area of trough crossbedded strata has radial structural dips inward, like a saucer, and the dips in the center are nearly flat. The other strata further away from the plate area also exhibit gentler dips toward it. I would expect from the nature of the internal cross stratification that it was originally deposited horizontal. That means that there has been subsequent folding or, more likely, subsidence directly under Home Plate to create the current configuration. There have been some ideas put forward as to the origin of the structure, including impact and volcanic cratering. I think we also have to incorporate some of this structural evidence into the feature origin and history...maybe we are looking at accommodation generated by (okay, say it like Dr. Evil...) magma withdrawl in below a maar or other type of volcanic crater.

Posted by: Bill Harris Oct 9 2007, 08:38 AM

This is indeed a special place. I seem to recall that the "Inner Basin" wsa the original target area, but the first part of the misson was changed to the hillclimb looing up the section for water since the original lacustrine environment wasn't panning out. We did get great science going the route we took, but think of what we could do at Homeplate not being a Three-legged Dog.

Seems to me that she is heading toward the vonBraun feature, which may be an erosional remnant higher in the section, and the Goddard feature, which may turn out to be more than a simple impact.

--Bill

Posted by: dburt Oct 9 2007, 09:07 PM

QUOTE (tdemko @ Oct 8 2007, 04:50 AM) *
Great place for the clastic sedimentologists! This is the best view, so far, of a number of stacked trough crossbed sets, showing nice tangential toesets and truncation surfaces. You also get a good sense of the unidirectional nature of the transport direction (successive sets are all dipping the same direction). Still looks like an eolian deposit to me...
One aspect of Home Plate region that still bugs me is the current structural geology...this area of trough crossbedded strata has radial structural dips inward, like a saucer, and the dips in the center are nearly flat. The other strata further away from the plate area also exhibit gentler dips toward it. I would expect from the nature of the internal cross stratification that it was originally deposited horizontal. That means that there has been subsequent folding or, more likely, subsidence directly under Home Plate to create the current configuration. There have been some ideas put forward as to the origin of the structure, including impact and volcanic cratering. I think we also have to incorporate some of this structural evidence into the feature origin and history...maybe we are looking at accommodation generated by (okay, say it like Dr. Evil...) magma withdrawl in below a maar or other type of volcanic crater.

Tim - Pardon my ignorance, already amply demonstrated here smile.gif , but how does a stacked sequence of small unidirectional cross-sets necessarily indicate eolian (wind) deposition? Why couldn't you see the same feature produced by other types of unidirectional currents - such as those provided by flowing water or volcanic/impact surges? If they were deposited by wind, what process or processes would have cemented the eolian deposits into the rock we see now? Also, would the rocks necessarily have an "ashy" aspect?

Incidentally, if the Home Plate layered deposits are volcanic or impact surge deposits, as opposed to those deposited by wind or flowing water, then there is no structural geology problem depositing them at an original dip angle of 30 degrees or more - the sediments can be sufficiently sticky when first deposited to allow this - "instant rock" as per my previous post. (In extremely wet cases, surge deposits can be plastered up against one side of trees.) On Earth it is common to see steeply dipping surge deposits extending radially upwards and outwards from a volcanic explosion crater, somewhat like petals from a flower - and also somewhat like rampart craters on Mars. That was one feature that led Wohletz and Sheridan (1983) to propose that martian rampart craters could have formed by impact surge processes. Of course, there may be some other explanation, such as collapse related to local magma withdrawal beneath Home Plate, as you hypothesize (although personally, given the lack of lava flows or volcanic constructs in the vicinity, I might be more tempted to go with collapse related to local ice melting), but Spirit's structural observations to date would not seem to require any such collapse process. At least not if the beds are surge deposits.

-- HDP Don

Posted by: tdemko Oct 10 2007, 12:49 AM

QUOTE (dburt @ Oct 9 2007, 04:07 PM) *
Tim - Pardon my ignorance, already amply demonstrated here smile.gif , but how does a stacked sequence of small unidirectional cross-sets necessarily indicate eolian (wind) deposition? Why couldn't you see the same feature produced by other types of unidirectional currents - such as those provided by flowing water or volcanic/impact surges? If they were deposited by wind, what process or processes would have cemented the eolian deposits into the rock we see now? Also, would the rocks necessarily have an "ashy" aspect?


It's more the shape and geometry of the foresets, with long, tangential toesets, and that successive crossbed sets have similar shapes, geometry, and stratal terminations. The succession suggests to me the migration and superposition of a series of 3D dunes of identical size and shape, with an angle of climb such that only the lower part of the foresets were preserved. The grain size and sorting also support an eolian transport mechanism. There are low-angle truncation surfaces that separate some of the cosets, and some changes in foreset angle that could be the result of reactivation. The most likely depositional environment that could produce this series of lithofacies and bounding surfaces seems to me to be a sand sheet (zibar) or series of low-relief transverse eolian dunes (see the "Abyss"). I guess what it comes down to us that I've seen many more terrestrial outcrops of ancient deposits and trenches of modern eolian environments that look exactly like this than I have seen volcanic/impact surge deposits. The surge deposits that I have seen just do not have the multiple levels of organization that eolian sediments seem to have.

Posted by: dburt Oct 10 2007, 05:21 AM

A good description of some terrestrial sand deposits, perhaps, but I'm not sure it is a good description of what actually can be seen in the Home Plate image you apparently based it on, here:
http://qt.exploratorium.edu/mars/spirit/navcam/2007-10-07/2N245061747EFFAVFUP0716R0M1.JPG
Little in that image of a poor outcrop seems as perfectly regular as you describe, at least not to my untrained eyes. huh.gif (I do see a pleasing uniformity in the shape and apparent transport direction for some of the adjoining cross-sets in the near-rover bottom part of the image, and that the overall bedding thickness is pretty thin, as usual at Home Plate, but that's about all - nothing that would necessarily be unique to wind, or that can be seen to continue for any great distance. And the scale implies that your "dunes" must have been tiny, to say the least. smile.gif ) Also, you didn't discuss what bulk processes might cement such eolian deposits into a uniformly hard rock on Mars.

AFAIK, there are no terrestrial examples of non water-reworked impact surge deposits that were laid down on a planetary scale (and later were reworked and redistributed by smaller impacts). At the time of the Late Heavy Bombardment, Mars had a denser atmosphere and lots of subsurface ice and brine to vaporize, even more than today. Even miniscule (by comparison) volcanic surge deposits tend to become strongly size-sorted with increasing distance from the explosion crater, and in their distal reaches can become well-sorted, thin-bedded sandstones. These can strongly resemble eolian deposits, as described in previous posts. On Mars loose eolian sands could have been scoured and incorporated into the rapidly moving surge cloud, increasing the resemblance even at the microscopic scale. If Home Plate is a surge deposit (whether volcanic or impact-related), then the cementation and structural problems implied by eolian deposition are taken care of automatically - instant rock, deposited with original dip. Do you see any intrinsic problems, other than your expectations perhaps, with the surge deposit explanation for Home Plate?

-- HDP Don

Posted by: Stu Oct 10 2007, 05:05 PM

Colourised view of today's best-looking rocks... really like this grouping... smile.gif


Posted by: don Oct 10 2007, 08:51 PM

dburt - Sooner or later surge deposition would apply to a location on Mars. Sure enough, accretionary lapilli, basaltic glass (TES), a fining upward sequence, and one bomb sag at HP make it almost a slam dunk, maybe more of a free throw. Not terribly surprising given regional volcanism and the impact marred terrain. That bomb sag loosely suggests wet sediments when deposited so perhaps the initial stages of cementation were not far behind.

Recently I visited the modern pyroclastic surge deposits of Mt. St. Helens (along the North Fork Toutle River and South Coldwater Creek). Massive deposits were the norm, strongly sorted, fines depleted, and visible shear zones. Blast debris clearly mixed within coarsely layered material. Silt- and clay-sized material present in thin layers, yet not common. Granted, one volcano in the northwest U.S. does not constitute a statistically valid comparison (any more than one example in New Mexico does) but the pyroclastic surge deposits viewed at St. Helens shared little visual similarity to the formations examined at HP (I’ll also include Meridiani in that comparison).

don

Posted by: dburt Oct 10 2007, 11:58 PM

QUOTE (don @ Oct 10 2007, 01:51 PM) *
dburt - ...Granted, one volcano in the northwest U.S. does not constitute a statistically valid comparison (any more than one example in New Mexico does) but the pyroclastic surge deposits viewed at St. Helens shared little visual similarity to the formations examined at HP (I’ll also include Meridiani in that comparison).

Other don - Agreed. Is there any particular reason why they should look the same? Should, for example, all water-deposited sediments look the same? What I continue to find interesting is that the Home Plate deposits, which are called volcanic surge, look almost exactly like the Meridiani deposits (except for the spherules in some layers, and rare crystal-shaped cavities), which are called something completely different. And the volcanic surge hypothesis for HP seems to rest on a single ballistic sag, a feature that shouldn't be unique to volcanism (nor should basaltic glass). So how would you account for the fairly obvious family resemblance between the beds at Home Plate and Meridiani?

About "initial stages of cementation" - all you have to do to "cement" a wet surge deposit is simply to dry it out (especially on Mars, where it will probably never be rained on). Bulk shrinkage cracks and an adobe-like consistency may result. On Earth, weathering and diagenesis may produce other changes over time, of course.

And about "sooner or later" - I'd probably make that sooner. Two rover landing sites explored, two impact surge deposits discovered, would still be my working hypothesis. So far, to my admittedly prejudiced eyes, this exceedingly simple idea still accounts for all rover observations (but may both rovers keep exploring long enough to test it much further! smile.gif ).

-- HDP Don

Posted by: tdemko Oct 11 2007, 12:24 AM

QUOTE (dburt @ Oct 10 2007, 12:21 AM) *
Little in that image of a poor outcrop seems as perfectly regular as you describe, at least not to my untrained eyes. huh.gif (I do see a pleasing uniformity in the shape and apparent transport direction for some of the adjoining cross-sets in the near-rover bottom part of the image, and that the overall bedding thickness is pretty thin, as usual at Home Plate, but that's about all - nothing that would necessarily be unique to wind, or that can be seen to continue for any great distance. And the scale implies that your "dunes" must have been tiny, to say the least. smile.gif ) Also, you didn't discuss what bulk processes might cement such eolian deposits into a uniformly hard rock on Mars.


Here is a quick line drawing of my interpretation of the bounding surfaces and trough crossbed sets that are visible in the current vicinity of Spirit:



They are the same size and style of crossbeds first seen at "Gibson" where Spirit first closely imaged the light colored, upper strata at Home Plate, and has since seen at every other locality visited within this strata. Because of the structural dip of this upper unit at the current locality, we are seeing a thicker apparent stratigraphic succession here. This is the most stratigraphically continuous unit, other that surficial and recent impact deposits, that Spirit has encountered. And as you can see from the excellent route maps at other places on this site, it has a limited outcrop area. When Spirit leaves area of Home Plate (including the visible outliers of light colored strata), these strata are not present and presumably were not deposited there or eroded away. However, it seems to be of uniform grain size, sorting, composition, bedding thickness, and cross bedding style everywhere present. I do not know how much more "regular" it can get without being perfectly horizontally laminated or completely massive and featureless!

Bedding thickness in eolian deposits depends upon the original bedform height, the angle of climb of successive migrating bedforms, the depth of scour or deflation on the lee side of the bedform, and any accommodation developed during the time of deposition (subsidence). The preserved cross bed set thicknesses at Home Plate are not out of range of what I would expect based upon the modern eolian bedforms seen by both Spirit and Opportunity. Close-ups of the strata at the lamination scale have also shown pin-stripe lamina, and grain-flow tongues at the base of some of the crossbed foresets. Maybe I buy my blades at a different place than you, but the razor is cutting eolian in my view...

Finally, sediments can be indurated by many processes and substances. It only takes a vanishingly small amount of cement right at grain-to-grain contacts (and even then, not at every grain contact) to make sediment stick together. There are surficial cements associated with weathering and meteoric processes and subsurface cements associated with fluid flow, alteration, and diagenesis. Spirit and Opportunity have encountered several possible sediment-cementing substances, including sulfates and amorphous silica. The surrounding strata at Home Plate is mostly of volcanic origin and there may have been several phases of fluid and gas flow through the Home Plate strata associated with eruption and deposition of these units. Home Plate strata may have even been buried by these units and since exhumed by erosion. Suggestions of alteration at other Gusev localities indicates alteration by water, presumably ground or hydrothermal water. It will take a thin section or two, and possibly some geochemical analysis, to fully reconstruct the paragenetic sequence of the Home Plate cross-bedded strata. Until then, all we have are jpeg's and our imagination...the JPL folks have a little more, and I eagerly await their interpretation!

Posted by: dburt Oct 11 2007, 01:17 AM

QUOTE (tdemko @ Oct 10 2007, 05:24 PM) *
Here is a quick line drawing of my interpretation of the bounding surfaces and trough crossbed sets... I do not know how much more "regular" it can get without being perfectly horizontally laminated or completely massive and featureless!...
Maybe I buy my blades at a different place than you, but the razor is cutting eolian in my view...
Finally, sediments can be indurated by many processes and substances...

Tim - Thanks much for your clear line drawings. We are indeed seeing exactly the same thing - the work of a current of some kind on fine sediment. I am less ready than you to ascribe it to eolian sedimentation, given the viable alternatives with fewer problems. (One famous sedimentologist, not a colleague of mine, said of a similar Home Plate feature that it looked like it was produced by flowing water - and this was just in the last few days!) In this regard, do you see any possible relation of your aeolian "trough crossbed sets" at HP to the "trough-style crossbeds" or "festoons" that have been claimed to indicate flowing water at Meridiani?

Agreed, we buy our blades at different places (I presume you are referring to Occam's razor). I can't make wind account for every observed feature - including all the ejecta blocks scattered across the top of Home Plate. Also, how can the "eolian" beds on top be perfectly conformable (parallel) with the surge beds underneath unless they also are surge deposits? Only surge deposits commonly have original dip (are deposited with inclined main bedding planes).

Agreed also about cementation being able to occur in many different fashions. The rock seems to be uniformly cemented in bulk, which rules out surface cements (salt encrustations, etc.). I see no direct evidence of Home Plate being of volcanic origin (no lava flows, no volcanoes, no vents, no craters) or of hydrothermal events (no quartz veins, no alteration haloes, no resistant siliceous mounds) - all I see are various compositions of fragmental ejecta (both fine and coarse), which could have come from anywhere. I therefore tentatively eliminate some sort of volcanic vapor phase alteration as a cementing agent. So we'll have to agree to disagree - I much respect your opinion.

-- HDP Don

Posted by: MahFL Oct 11 2007, 10:32 AM

Did Spirit just image a bunch of metorites on top of Homeplate ?

http://qt.exploratorium.edu/mars/spirit/pancam/2007-10-10/2P243016524EFFAV00P2388L5M1.JPG

pancam.gif

Posted by: Tesheiner Oct 11 2007, 10:56 AM

That's an "old" image from sol 1314.

01314::p2388::18::24::0::0::24::2::50::pancam_fracture_4x1_L257R127

Posted by: alan Oct 12 2007, 02:11 AM

Nice view of Husband Hill. Part of larger panorama that hasn't finished downloading yet. Yes I am impatient.


Posted by: mhoward Oct 12 2007, 04:26 AM

Gorgeous, alan. I think the finished panorama is going to be one of the best of the mission. I wonder what they are calling it.

Here is one very small section of the same pan facing the other direction, showing Spirit at her present location using Doug's rover model.

http://www.flickr.com/photo_zoom.gne?id=1548736190&size=l

Posted by: Stu Oct 13 2007, 12:44 PM

Our favourite martian hill, with my attempt at making her look a little more realistic...


Posted by: Ant103 Oct 15 2007, 08:29 AM

Hi,

Good work Alan and Stu smile.gif.

Here is the first part of the wide pano coming next :
http://astrosurf.com/merimages/Images_de_spirit-2007.html#Sol1326

And the traditional wallpaper wink.gif
http://astrosurf.com/merimages/Desktop/SurHomePlate-Sol1326-1327-desktop.png

Posted by: n1ckdrake Oct 15 2007, 09:34 AM

Spirit Sol 1334


Posted by: TheChemist Oct 15 2007, 09:59 AM

Nice panorama n1ckdrake !
[but wrong forum smile.gif . Maybe one of the moderators could move it http://www.unmannedspaceflight.com/index.php?showtopic=4553&pid=102100&st=120&#entry102100, at the "Home Plate (second round)" thread]

Done. J

Posted by: Floyd Oct 15 2007, 12:38 PM

Nice panorama n1ckdrake. I'm sure it would upset the local naming conventions, but that one large rock has to be named Shark's Tooth.

Posted by: Stu Oct 15 2007, 03:30 PM

Shark's Tooth is a pretty cool rock...


Posted by: bgarlick Oct 15 2007, 05:47 PM

n1ckdrake's panorama looks nice, but be warned that there is a fair amount of duplicated imagery in that picture. There is a vertical seam
that duplicates one of those overhanging lobe like resistent layer outcrops and there is lots of replicated imagry between the high gain antenna and the UHF (VHF?) antenna.

Posted by: n1ckdrake Oct 15 2007, 09:37 PM

Thanks for the comments! You are correct bgarlick, there is a good amount of duplicated imagery in the corners and to the left of the rover. You have a really good eye. laugh.gif
Shark's Tooth is the perfect name for that unique rock, Floyd. There are some really nice closeup images of that rock from Pancam Sol 1344.
Stu, Ant103, Alan, nice work on Husband Hill. I like the addition of the sun added to the background.

Posted by: CosmicRocker Oct 16 2007, 03:50 AM

Shark's Tooth sounds like a good name for this rock, but I think the name may have already been taken. I can't remember where, though. I've been curious about these pyramidal rocks since Spirit landed in Gusev Crater. Why are there so many similarly shaped, pyramidal or pointed boulders in this hard rock terrain? Two well known boulders with similar shapes are Adirondak and Humphrey, but we have seen very many such boulders. I've concluded that rocks of this shape are the common result of impact shock waves.

Whatever their origin, the set of stereo subframes that came down today begged me to create an anaglyph view.


Posted by: PaulM Oct 16 2007, 07:43 AM

I think that the angular rocks seen by Spirit are ventifacts. Ventifacts form in the Earths deserts when rocks are sand blasted by wind first from one direction and then from another. The angle forms where the two blasted surfaces meet.

I collected my only Ventifact from sands lain down in an Arctic desert at Jodrell Bank.

Posted by: Tesheiner Oct 16 2007, 08:31 AM

QUOTE (n1ckdrake @ Oct 15 2007, 11:37 PM) *
Thanks for the comments! You are correct bgarlick, there is a good amount of duplicated imagery in the corners and to the left of the rover.

Dunno which sw are you using to make such mosaics. Have you tried autostitch? You'll be surprised by its incredible results.

Posted by: n1ckdrake Oct 16 2007, 10:28 AM

Tesheiner, thank you for mentioning Autostitch to me. I just downloaded it and so far I'm really impressed.

Posted by: Tesheiner Oct 16 2007, 10:52 AM

Have a look to this thread too for some tips: http://www.unmannedspaceflight.com/index.php?showtopic=1071.

Posted by: jamescanvin Oct 16 2007, 02:26 PM

Still a little more of the site 3 360 degree panorama to come down, but the L7 is all here. smile.gif

This is just a quick test of the stitch really, so there is a lot of contrast mismatch, but I thought I'd post it to give you lot a quick preview.



James

Posted by: climber Oct 16 2007, 03:10 PM

QUOTE (jamescanvin @ Oct 16 2007, 04:26 PM) *
Still a little more of the site 3 360 degree panorama to come down, but the L7 is all here. smile.gif
This is just a quick test of the stitch really, so there is a lot of contrast mismatch, but I thought I'd post it to give you lot a quick preview.
James

Pretty "shark" pano anyway wink.gif
Thanks, it realy gaves another perspective with new land visible.

Posted by: Tesheiner Oct 16 2007, 03:21 PM

Outstanding job James! I'm looking forward the color version...

I finished my own version of the mosaic just a few minutes ago! laugh.gif
I used R1 instead of L7 and didn't apply any balance to equalize the brightness difference of all the images (54 pictures is too much to do it manually!!!) so the end result isn't really great. Here is a thumbnail version; the full size is too big (8.5MBytes) to post here.



On a different topic, this current sol (1346) Spirit may start the move towards the west corner.

Posted by: n1ckdrake Oct 17 2007, 02:38 AM

Tesheiner, thanks for the link to the Autostitch thread. What a great little program this is! smile.gif
Nice work on those panoramas Jamescanvin, Tesheiner.

Posted by: CosmicRocker Oct 17 2007, 02:57 AM

QUOTE (PaulM @ Oct 16 2007, 02:43 AM) *
I think that the angular rocks seen by Spirit are ventifacts. ...
I won't argue with that, Paul. Most of the faceted boulders we see in Gusev are undoubtedly ventifacts. I was only suggesting that certain of the tooth-like rocks may have been initially shaped by impact fracturing.

Thanks for the panos, James and Tesh. This one will be awsome in color. We can see the structure of Home Plate very well from this position. smile.gif

Posted by: Tesheiner Oct 17 2007, 08:29 AM

Sol 1346 images are coming down. Spirit left the vicinity of "Humboldt Peak" and moved about 10m to the west.

http://nasa.exploratorium.edu/mars/spirit/rear_hazcam/2007-10-17/2R245862845EFFAVHPP1312R0M1.JPG

 

Posted by: Tesheiner Oct 17 2007, 09:40 AM

Here is the latest navcam mosaic (right eye).
The west corner can be seen on the second frame from the left and there seems to be a "nice" step right there. An anaglyph might tell the truth.


Posted by: jamescanvin Oct 17 2007, 01:39 PM

"Shark's Tooth Ridge" wink.gif Sol 1344

http://www.physics.usyd.edu.au/~jcanvin/mer/index.html#A1344

James

Posted by: ngunn Oct 17 2007, 04:11 PM

I notice a lot of parallel alignment (bottom left to top right) among the dark rocks around the tooth. I had assumed these were just boulders, which ought to be randomly oriented. Or are we looking at steeply inclined layering in some in-situ outcrop? A single very large boulder being eroded into small in-situ fragments? Or is it just a chance effect?

Posted by: fredk Oct 17 2007, 05:45 PM

I see the alignment. Speaking of "ventifacts", could prevailing wind directions help explain it?

Posted by: fredk Oct 17 2007, 06:21 PM

Yeah, Tesheiner, an anaglyph does help a lot here. In fact, I think this is one of the nicest views we've had in a long time. I'm surprised at how high we appear to be above the plain. I can't wait for the view south towards Goddard/Von Braun once we move farther west...


Posted by: fredk Oct 17 2007, 06:27 PM

\begin{silly looking-for-shapes-in-rocks mode}

Shark tooth you say? There's an entire shark surfacing off to the left... blink.gif


\end{silly looking-for-shapes-in-rocks mode}

Posted by: ngunn Oct 17 2007, 07:02 PM

QUOTE (fredk @ Oct 17 2007, 06:45 PM) *
I see the alignment. Speaking of "ventifacts", could prevailing wind directions help explain it?


Well it seems very localised, confined in fact to the extreme left end of James's mosaic. Also I could persuade myself that the alignment is shared by surface markings on the large rock platform the Shark's tooth is sitting on. The tooth itself is the exception, being oriented more nearly to the vertical. However, looking at its bottom left corner and the concavity in the rock behind - it could have slipped downhill to the right and rolled anticlockwise a little.

Posted by: jvandriel Oct 17 2007, 07:25 PM

A panoramic view of part of the edge of Home Plate.

Taken on Sol 1344 with the R1 Pancam.

jvandriel


Posted by: jvandriel Oct 17 2007, 09:35 PM

Here is my version of the 360 degree panoramic view

taken between Sol 1305 and Sol 1319 with the R1 Pancam.

The original pano is 30.9 MB.

jvandriel


Posted by: mhoward Oct 18 2007, 01:07 AM

QUOTE (fredk @ Oct 17 2007, 11:21 AM) *
Yeah, Tesheiner, an anaglyph does help a lot here.


The anaglyphs certainly help; without them, one might think that the top of Home Plate is pretty flat. Also in the anaglyphs, it looks like a nice possible 'exit ramp', due west.

Unrelated visualization:

http://www.flickr.com/photo_zoom.gne?id=1606324725&size=l

Posted by: mike Oct 18 2007, 02:38 AM

QUOTE (fredk @ Oct 17 2007, 11:27 AM) *
\begin{silly looking-for-shapes-in-rocks mode}

Shark tooth you say? There's an entire shark surfacing off to the left... blink.gif
\end{silly looking-for-shapes-in-rocks mode}


That's no ordinary shark. It's Jaws.

Posted by: Shaka Oct 18 2007, 07:12 AM

Actually, on the crest of the ridge, just right of the "tooth", there could be an outcrop of pre-Home Plate bedrock worth examining, but it might be rather inaccessible to our 'lame' rover. (Though I must confess I'm impressed by its alacrity in crossing HP so far. I feared the stuck wheel might anchor us to the bedrock every other meter, but it seems to have surfed over much of the surface without grief. The occasional bigger shard has been plowed up and left in the wake.) So far so good! smile.gif

Posted by: Tesheiner Oct 18 2007, 09:53 AM

QUOTE (mhoward @ Oct 18 2007, 03:07 AM) *
The anaglyphs certainly help; without them, one might think that the top of Home Plate is pretty flat. Also in the anaglyphs, it looks like a nice possible 'exit ramp', due west.

Yup. I saw that ramp too.
Spirit is now, after driving again tosol (1347), on the way to the west corner and almost beside that possible exit ramp. Here is the latest navcam mosaic.
Watch your step, baby!!!

Posted by: alan Oct 19 2007, 09:00 AM

I've been looking forward to seeing Von Braun again

http://qt.exploratorium.edu/mars/spirit/navcam/2007-10-19/2N246040788EFFAVLFP0727R0M1.JPG

Posted by: Bill Harris Oct 19 2007, 09:50 AM

I've been looking forward to visiting vonBraun (and Goddard) for a long while...

--Bill

Posted by: Tesheiner Oct 19 2007, 10:34 AM

Me too! (Seeing AND visiting). smile.gif
Here is the whole view south. I don't know about you, but I was a bit bored of that same panorama to the south day after day during this last year; now we have Von Braun (aka "Pitcher's Mound" before JPL used such name for a feature near Silica Valley) on sight again.



Regarding the "exit ramp" we talked before, I'm now worried that it's actually a "sand trap" for our lame rover. huh.gif

Posted by: MahFL Oct 19 2007, 02:49 PM

Where is Spirit heading inthe medium and long term ? And can someone plot a future possible path on a homeplate image please ?

Thanks.
pancam.gif

Posted by: fredk Oct 19 2007, 04:26 PM

Finally, the view to von Braun! Beautiful.

MahFL, the short term goal is the SW corner of homeplate. Before we get too close to next winter, they have proposed driving to the north-facing slopes of von Braun. That's why this view is so important.

You're right Tesheiner that it looks like untraversable dunes directly below our current location. But I think the driving would be much better further to the left in your pan, where we could pick our way through the boulders to that isolated light-coloured outcrop below and to the left of von Braun (we'll need a name for it!). I imagine they might like to sniff that outcrop anyway.

From there we'd have a clear view of the surface all the way to von Braun. But from what we can see now, the plain surrounding von Braun looks quite good. Scattered dunes and boulders. Pancam views will be helpful.

Posted by: Shaka Oct 19 2007, 09:19 PM

A major question is whether there are deeper strata exposed at the base of HP between here and the northwest corner (already visited). So we have to get down the 'precipice' here somewhere sooner or later. The key decision is whether to first survey the top of HP on this side while we look for a good descent ramp. That would seem to be the more efficient course, and should also maximize our chances of catching cleaning wind gusts on top. Of course, if someone's crystal ball predicted that Spirit would conk out in ten days time, I would favor a quick descent now to survey the base of the exposure. The deepest exposure could offer major discoveries about HP that are not accessible on the top. How confident are we about Spirit's continued longevity? unsure.gif

Posted by: Ant103 Oct 19 2007, 09:46 PM

Hi,

Two preview of parts of the "H&H Panorama", the name I gave for it (H like Home Plate, and H like Husband Hill, visible on the pano wink.gif).

 

Posted by: Ant103 Oct 19 2007, 09:48 PM

Part two :

PS : when it finish, I'll give you a surprise wink.gif.

 

Posted by: CosmicRocker Oct 20 2007, 02:22 AM

It was exciting to wake up this morning and see Von Braun in my MMB update. It was better yet to realize that soon Spirit would be heading toward that long-awaited goal. smile.gif The view from this location is breathtaking in 3D, so I made an anaglyph of the pano. The left and right sides stitched somewhat differently, so I had to adjust one side to make it fit the other. The horizon is not perfect, but the rest is decent. If you're lucky enough to have multiple monitor desktop, it's an awesome view.

626 KB
It's really fascinating to compare features in this view to the HiRise image in Tesheiner's map. It appears way too steep to drive off HP around here, but that ramp we saw a few locations back appears feasible. I agree that we should avoid the drifts and follow a route that hugs the light colored, anvil shaped outcrop.

Posted by: fredk Oct 20 2007, 04:31 PM

Some http://qt.exploratorium.edu/mars/spirit/pancam/2007-10-20/2P246122818EFFAVLFP2404L2M1.JPG north-facing slopes out there...

Posted by: Stu Oct 21 2007, 09:41 AM

Great views coming up I think...! smile.gif


Posted by: peter59 Oct 21 2007, 05:55 PM

Sol 1351
Expected EDRs by sequence number and image type:
Sol Seq.Ver ETH ESF EDN EFF ERP Tot Description
----- -------- --- --- --- --- --- ---- -----------
01351 p1550.01 2 0 1 0 0 3 navcam_tau
01351 p1567.00 1 0 0 0 0 1 dd_watch_az_275_max10mbits
01351 p2113.13 13 13 0 0 2 28 pancam_magnet_array_L234567Rall
01351 p2123.05 26 26 0 0 2 54 pancam_cal_w_sweep_L234567Rall
01351 p2405.18 18 0 0 18 1 37 pancam_LBLS_pt2_L2
01351 p2600.11 2 2 0 0 2 6 pancam_tau
01351 p2600.11 2 2 0 0 2 6 pancam_tau
01351 p2600.11 2 2 0 0 2 6 pancam_tau

Where Von Braun's L7R1 sequence?
Is Von Braun not interesting ? After all, each day may be the last Spirit's day.

Posted by: djellison Oct 21 2007, 06:27 PM

I'd have thought the Whrs & Mbits would be dedicated to navigation to get to the local science before planning the move to VB. We got pancam imagery of VB a few sols ago - techncially we're slightly further away now so there would be no new value in Pancam obs of it again (save for Long Baseline Stereo). Clearly VB IS interesting or they wouldn't be planning to use it for the winter layover.

Doug

Posted by: fredk Oct 21 2007, 06:47 PM

QUOTE (djellison @ Oct 21 2007, 06:27 PM) *
(save for Long Baseline Stereo)
Speaking of which...

(sols 1348 and 1350)

PS, thanks for the anaglyph pan, CR - I was wishing I could put together such a view!

Posted by: Stu Oct 21 2007, 11:01 PM

View getting better each sol...



Posted by: CosmicRocker Oct 22 2007, 04:42 AM

Nice work on the LBL anaglyph, fredk. The depth of field is impressive. I messed around with it a while today, but it looked like more work than I was prepared to devote. blink.gif

The sol 1349 Pancam panorama came down and I have been mesmerized by it all day. Here is a Pancam anaglyph of VB and environs. We finally get a rather good look back at the stratigraphy of Shark's Tooth Ridge as it relates to Home Plate, and the curious, light-colored outcrop to its right. I'd like to hear what others think, but the light-colored outlier really looks like the Home Plate layers to me. There is cross-bedding on top, with a coarser textured unit below. It appears to me that the dips have reversed.


I know I said that last view was amazing, but this one is to die for. cool.gif

Posted by: Phil Stooke Oct 22 2007, 01:56 PM

peter59: "Where Von Braun's L7R1 sequence?
Is Von Braun not interesting ? After all, each day may be the last Spirit's day."


Wolf! Wolf!

'Each day may be the last' was a reasonable argument 1000 sols ago, but I think it's now become more acceptable to take a chance on surviving the night. We can afford to get into a better position, or devote resources to another target, or whatever they are up to.

Phil

Posted by: Nix Oct 22 2007, 03:33 PM

QUOTE (CosmicRocker @ Oct 22 2007, 06:42 AM) *
...........but this one is to die for. cool.gif


It sure is!

Nico

Posted by: algorimancer Oct 22 2007, 05:09 PM

QUOTE (CosmicRocker @ Oct 21 2007, 11:42 PM) *


I really hope that a drive to VonBraun is in the cards at some point. I'd really like a close-up view of the plate there, and especially a look at that circular basalt dike-like feature to its left. I'm sure there's much more work to be done on Home Plate before that happens, however.

Posted by: CosmicRocker Oct 23 2007, 04:26 AM

Thanks, Nico. smile.gif

QUOTE (algorimancer @ Oct 22 2007, 12:09 PM) *
I really hope that a drive to VonBraun is in the cards...
Yikes! Are you kidding? I thought the "official plan" was to finish up at Home Plate and then make a mad dash to Von Braun. There is so much to see all around here. We can only hope that Spirit is up to the task. It looks like quite a perilous journey to me.

We have HiRise imagery for a 3D look at this area from orbit. I don't recall anyone posting a HiRise anaglyph of this region yet, so here is my version of the topography from HP to VB.


Posted by: ngunn Oct 23 2007, 07:43 AM

QUOTE (CosmicRocker @ Oct 23 2007, 05:26 AM) *
here is my version of the topography from HP to VB.


Now that is VERY nice and most useful for visualising the area - thanks CR.

Posted by: ustrax Oct 23 2007, 01:25 PM

Wow!
Thanks for those anaglyphs guys...the closest to hike Mars we can get close too... wink.gif

Posted by: Tesheiner Oct 23 2007, 01:58 PM

The images of today's drive (yes, it was a driving sol) didn't hit the exploratorium, but some data are already available at the data tracking web.
And the news are that Spirit moved back 7m to the east.


Posted by: algorimancer Oct 23 2007, 03:36 PM

QUOTE (CosmicRocker @ Oct 22 2007, 11:26 PM) *
...
We have HiRise imagery for a 3D look at this area from orbit. ...



Thanks for that, that's the first hires anaglyph looking down on Home Plate that I've seen. I remain intrigued... just what the heck is that tear-drop shaped feature to the east of VonBraun? From above it is a tear-drop shape with a sharp outline and a depression, which otherwise I might be persuaded is a crater, except that from the side view it seems to have nearly vertical basalt walls. Might it be a volcanic vent? There's also a distinct bright layer visible in the overhead view along the eastern circumference.

Posted by: climber Oct 23 2007, 04:26 PM

Thanks CR, this is realy amazing view.
Regarding what Algorimancer is talking about, I can at least 2 other features looking the same. The one you're talking about is looking like a nearly empty half egg with the shell visible. I know that's pure poesy, but anyway...

Posted by: algorimancer Oct 23 2007, 05:42 PM

QUOTE (climber @ Oct 23 2007, 11:26 AM) *
...I can at least 2 other features looking the same. ...


Where?


And just to simplify any subsequent discussion, I'll dub this thing "Von Braun's Tear" smile.gif [Retracted- official name Goddard]


The wikipedia entry on cinder cones may be relevant:

http://en.wikipedia.org/wiki/Cinder_cone

Take a look at that image

http://upload.wikimedia.org/wikipedia/en/1/10/Cinder_cone_diagram.gif

If you eroded away all but a stub of a cinder cone, leaving only the basalt-lined volcanic vent, it looks to me like you'd have something resembling the Tear. It seems to me that its close proximity to Von Braun is not a coincidence. If Home Plate formed as an accumulation of ash above a volcanic vent, then it seems logical that Von Braun must have done the same, but in the latter case erosion has subsequently removed most of the plate and exposed the vent. That's pretty nifty, assuming it is correct smile.gif

Posted by: fredk Oct 23 2007, 07:35 PM

The teardrop-shaped feature does have an official name, http://www.jpl.nasa.gov/missions/mer/images-print.cfm?id=2096

Posted by: algorimancer Oct 23 2007, 07:47 PM

QUOTE (fredk @ Oct 23 2007, 02:35 PM) *
...http://www.jpl.nasa.gov/missions/mer/images-print.cfm?id=2096

Good to know, thank you. I retract "Tear" smile.gif

Further, now that I know the name, I see that Phil Stooke has also suggested it as a volcanic vent - last December in the Spirit's New Adventures thread, post #144.

Posted by: jvandriel Oct 24 2007, 07:31 PM

Spirit looking back on Sol 1351

Taken with the L2 Pancam.

jvandriel

.

Posted by: Tesheiner Oct 25 2007, 08:19 AM

QUOTE (jvandriel @ Oct 24 2007, 09:31 PM) *
... Sol 1351


We are currently on the middle of sol 1354 and there are no new images at both the exploratorium or the official MER homepage since after sol 1351.
Don't panic! There are nothing wrong with the rovers because the pictures and other data are being downlinked and available right on time at the PCDT webpage.

For those of you interested on the events of these "missing" sols here it is:
Sol 1352: Spirit moved back east and shot a navcam mosaic and a "drive-direction" pancam mosaic looking southeast.
Sol 1353: Another move was planned but aborted for any reason.
Sol 1354 (tosol): Same plan as yestersol except the abort, I hope.

Posted by: fredk Oct 25 2007, 03:30 PM

Thanks, Tesheiner, I really appreciate that as I don't check the tracking site.

Drive direction southeast? Does that mean more retracing of our path, or could it mean they want to drive across to the "Saddle", which is what I call the separate, light-coloured outcrop to the southeast, which spans the centre of http://marsrovers.jpl.nasa.gov/gallery/all/2/p/1351/2P246299869EFFAVMAP2405L2M1.JPG and which to me seems to have a bit of a saddle shape.

Posted by: Tesheiner Oct 25 2007, 04:25 PM

The latter, I would say.
Here are the thumbnails from the tracking site.


Posted by: Tesheiner Oct 26 2007, 09:22 AM

Still no new images available at the exploratorium. sad.gif
But from the tracking web data I can confirm the plan executed during sol 1354: Spirit moved back southeastwards to a point near its site during sol 1347, shot a navcam mosaic looking due south followed by a "drive-direction" pancam mosaic pointing downwards.

Yup, I think we are taking the "exit ramp".

Posted by: alan Oct 27 2007, 02:07 AM

Site3 Panorama autostitched


Posted by: mhoward Oct 27 2007, 04:03 AM

QUOTE (alan @ Oct 26 2007, 07:07 PM) *
Site3 Panorama autostitched


Glorious. Here's a quick view from MMB2.0 (which I really need to fix to handle the color adjustment again, one of these days).

http://www.flickr.com/photo_zoom.gne?id=1769056912&size=l

Posted by: Phil Stooke Oct 29 2007, 12:36 AM

Here is a polar version of Alan's latest panorama.

Phil


Posted by: Tesheiner Oct 30 2007, 04:10 PM

We are now on sol 1359 and Spirit drove a little bit just a few hours ago.
Fresh pictures at the exploratorium, as usual, including the ones making this pancam mosaic.



Do we have an unnofficial name (UMSF name, I mean) for the rocky feature at the right foreground? I'll update the map with it.

Posted by: ngunn Oct 30 2007, 04:33 PM

QUOTE (Tesheiner @ Oct 30 2007, 04:10 PM) *
Do we have an unnofficial name (UMSF name, I mean) for the rocky feature at the right foreground?


I think this is what Fredk called 'The Saddle' - see post 190.

Posted by: Ant103 Oct 30 2007, 04:44 PM

Hi,

Big updates on my website (new banner, new micro-banner, new butttons...) and new images.


This is the "H&H" panorama as I named it.


The 360° directly out of autostitch :


And the "surprise", the same panorama but with a whole sky, from horizon to zenith, showing the sun, and other bodies like Earth and Jupiter, and two major stars, Antares and Arcturus (have good eyes to see these) at the place they would be take at the time of the acquistion of the panorama.
So, stop talking, the picture :

http://www.astrosurf.com/merimages/Images_de_spirit-2007.html#Sol1326

Posted by: Stu Oct 30 2007, 05:05 PM

Wow... Ant... words fail me, really they do... possibly one of THE images of the whole MER mission. That should be on APOD and many other websites if there's any justice.

My humble offerings...



and...


Posted by: Tesheiner Oct 30 2007, 05:18 PM

QUOTE (ngunn @ Oct 30 2007, 05:33 PM) *
I think this is what Fredk called 'The Saddle' - see post 190.

Thanks for pointing that. And now that I look back again to the image it really looks like a saddle. smile.gif

Posted by: Stu Oct 30 2007, 05:55 PM

... and a bit more "arty", just cos I'm in a creative - if not entirely accurate! - mood smile.gif


Posted by: n1ckdrake Oct 30 2007, 11:22 PM

That's a great looking image, Ant103.

Posted by: mhoward Oct 30 2007, 11:31 PM

QUOTE (Stu @ Oct 30 2007, 10:55 AM) *
... and a bit more "arty", just cos I'm in a creative - if not entirely accurate! - mood smile.gif


Ah yes, the Southern Sunset that Gusev is famous for... wink.gif

Posted by: Stu Oct 30 2007, 11:38 PM

That's not the Sun, silly, that's Comet Holmes shining thru the dust wink.gif

I did say "arty not accurate".

Posted by: mhoward Oct 31 2007, 02:16 AM

QUOTE (Stu @ Oct 30 2007, 04:38 PM) *
That's not the Sun, silly, that's Comet Holmes shining thru the dust wink.gif


Look out! That thing's coming in for a landing! ohmy.gif biggrin.gif

Posted by: Astro0 Oct 31 2007, 03:06 AM

I was working on an 'arty' version too, Stu! smile.gif
Enjoy
Astro0


Posted by: CosmicRocker Oct 31 2007, 04:03 AM

Ant103: Your surprise was wonderful. Send it to APOD, ASAP. wink.gif

Posted by: Tesheiner Oct 31 2007, 09:22 AM

A new status update at the MER site: http://marsrovers.jpl.nasa.gov/mission/status_spiritAll.html#sol1348

QUOTE
Spirit's handlers are currently confronted with the decision of where to send the rover for the winter. ... Members of the science team hope to find a place where Spirit can achieve a tilt of 20 degrees or more toward the north, facing the sun. ... Proposed locations for a winter haven include driving south down the off-ramp and making a break for "von Braun," a hill approximately 120 meters (390 feet) away; heading north across Home Plate and driving down the north-facing edge; or driving west of Home Plate to a hill tentatively identified as "West Knob."


Meanwhile, Opportunity's status update is frozen on Sep 20th...
I'm waiting for the monthly update by The Planetary Society which should be online today or tomorrow.

Posted by: Aussie Oct 31 2007, 09:30 AM

Ant, Breathtaking. Just imagibne without the dust contamination...

Posted by: jamescanvin Oct 31 2007, 11:58 AM

Dust contamination? I was about to say what a pleasure it is to work with Spirit and her nice [relatively] clean lenses for a change. smile.gif

Although I was also going to say what a right pain it is trying to process full resolution 360 degree panoramas using a P3 with 256Mb RAM, but that's all I have at the moment and at least it made me track down a few memory leaks. smile.gif

Home Plate Site 3 Panorama

http://www.physics.usyd.edu.au/~jcanvin/mer/index.html#A1325


Click image for resolution options up to the full 22890 x 3687.

Enjoy,

James

Posted by: Astro0 Oct 31 2007, 12:32 PM

Fantastic! - Ant, James and others.
Here's another version on this panorama theme.
Enjoy
Astro0


The full-res version is about 86mb and I simply don't have anywhere to put it to make it available online. Besides, I'm only using dial-up at home. blink.gif "Mmmmm, must get broadband" (I hope my wife is reading this over my shoulder) ph34r.gif

Posted by: Ant103 Oct 31 2007, 06:14 PM

Stu, Nc1', aussie, cosmic' and AstroO thanks for your comments. I have send it to the Apod. Whati is asap?


Recent catches from Spirit show the camera assembly reflection on the dock : http://marsrovers.jpl.nasa.gov/gallery/all/2/p/1358/2P246923790EDNAVQWP2292L4M1.HTML

Posted by: ElkGroveDan Oct 31 2007, 06:29 PM

QUOTE (Ant103 @ Oct 31 2007, 10:14 AM) *
What is asap?


As Soon As Possible

Posted by: jvandriel Nov 1 2007, 08:08 PM

The panoramic view taken on Sol 1351 and Sol 1352

with the L2 Pancam.

jvandriel


Posted by: jvandriel Nov 1 2007, 09:11 PM

and the Navcam view from Sol 1352 and Sol 1353

taken with the R0 Navcam.

It looks like the overlap between 2 images is greater as before.

jvandriel


Posted by: fredk Nov 2 2007, 04:55 AM

Disappointing news from http://www.planetary.org/news/2007/1031_Mars_Exploration_Rovers_Update_Spirit.html

QUOTE
At a meeting held 8 a.m., November 1, the team made its decision. Spirit will head north across Home Plate, drive a little way down the north facing edge, and winter there. "It was a pretty simple decision when it came down to it," said Squyres. If we head to Home Plate North, we wind up being about 10 drive sols farther from our goal, von Braun. We also wind up being on a steeper northward slope that buys us an additional 10 watt-hours. So it's a simple, straightforward trade of 10 watt-hours for 10 drive sols.
This means no von Braun/Goddard until next martian summer. Those tasty slopes will have to wait... sad.gif

Posted by: jvandriel Nov 4 2007, 12:05 PM

A panoramic view of wheelscratches on some of the Martian rocks.

Taken with the R1 Pancam on Sol 1354.

jvandriel


Posted by: jvandriel Nov 4 2007, 12:14 PM

The 360 degree panoramic view taken on Sol 1354 and Sol 1356

with the R2 Pancam.

jvandriel


Posted by: jvandriel Nov 4 2007, 12:17 PM

An MI mosaic taken with the Mi camera

on Sol 1360.

jvandriel


Posted by: n1ckdrake Nov 9 2007, 02:30 AM

Sol 1366


Posted by: n1ckdrake Nov 23 2007, 08:09 AM

A wider pan of Sol 1366.


Posted by: jamescanvin Nov 23 2007, 10:22 AM

Yeah, that's the top row of the "West Valley View" pan taken on sols 1366 to 1369. I'm still waiting for the L2 and L5 to come down for the colour version, but here is the full pan in L7 (at half resolution and quite heavily compressed)

James


 

Posted by: n1ckdrake Nov 24 2007, 02:48 AM

James, that full pan looks great. I'm impressed with the quality of the image for being so heavily compressed.

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