So now we're sailing in the north atlantic along the northeastern US COAST...watch out for JAWS next!

Block Island is visible in the HiRISE image, meaning it's fairly large, which is one reason we're going back. Other reason(s) I'll leave up to the reader! (more fun that way!)


-Tim.

I estimate Block Island is roughly 25 cm tall by 50 cm wide (orthogonal to our line of sight). That's assuming it's sitting at the same elevation as Oppy's wheels were, and also that the horizon was level with pancam. (Probably not horrible approximations on Meridiani!)

Could someone who has the full resolution HiRISE post a full res crop showing the area of Block Island? I estimate it's about 50 metres S or SSW from the sol 1942 location.

Looks like a Land Rover stuck in the Sahara..... kind of

Great news! This will take me more time to tweak my google earth map extension (it's proving trickier than i thought).

Hi FredK
Here's a crop of the region I think you want.
I may be wrong, can't see the rock.
I can crop a different area if you wish.

Roy F

Roy:

It's in there!

-Tim.

Would someone who can see where it is please circle it and repost the pic! Can't see it.

Click to view attachment

I can well understand why we're going to have a look. Not only does it look different to all the surrounding rock - it's also, I'd guess, the single largest rock not in a crater that Opportunity has ever seen.

Wow, that's a long drive back. Whatever it is that the rover team thinks this might be has got to be a lot more interesting than another iron meteorite!

Thanks for pointing the rock Tim.
Added it to the latest KML file in the route map thread.

Can someone summarize the reasons their taking the big west (almost northwest) turn? Is it more stable ground to drive on? Sorry if I missed this many pages back. Thanks!

Hmm. Well, as Doug pointed out, BI is an anomaly in its own right even on cursory examination. However, Tim is hinting that there are other less obvious reasons for the close-up exam.

It sure is dark, which to me indicates that might be a relatively recent, hefty meteorite. On the other hand, it might be an ejecta block from a fresh impact in the area...say, maybe from over near the recently-more-interesting region near Endeavour? Are you guys looking for clay early?

Was there perhaps a tantalizing mini-TES image taken? Does it even work on Opportunity anymore?

No.

So the attempt to clear the dusty mirror by leaving it exposed has failed?

Glenn, the size would depend on the meteor type and velocity. Was this a secondary? Was it at terminal velocity or faster? The link takes a lot of the effort out of 'what iffing' this question.
http://www.lpl.arizona.edu/tekton/crater_c.html

Serpens, thanks for the link to the crater diameter calculator -- it is fascinating! And I am perhaps not so far off! A 0.2 m diameter meteor of dense rock (not iron), traveling at 45 km/sec (the upper end of the range for Mars impacts), and striking "competent rock" will create a crater 3.49 m (appx. 12 feet) in diameter.

But Block Island is even more fascinating!!! Is anyone sure that's why we've turned around?

Doug has it. It's the biggest thing not associated with a crater that we've seen. And it's not outcrop.

-Tim.

Certainly reason enough. And there I was, spinning out into left field...

Alan, my man! What led you to this felicitous observation? Just your own curiosity about that big black rock?

Just thought 'hey that looks interesting' when MMB downloaded the images, that and 'too bad Oppy has already driven away'


I'm also wondering if it's located far enough south for Oppy to see some of the terrain to the south that's currently hidden from view.

I thought there was a significantly larger "erratic" boulder observed near Erebus. Some here were surprised that that one was not more closely investigated at the time. I'm not suggesting that either was a glacial erratic, only that it was an erratic boulder on Mars.

But what took the team so long to decide to turn around and go investigate BI? Someone maybe took a second look at the downloaded images a few days after their initial evaluation and raised a big flag? Would have been interesting to be a fly on the wall during that ops meeting....

Thanks for the maps, guys. I now measure the distance to BI to be 66 metres from the sol 1942 location. That gives a size for the rock of about 67 cm wide by 30 cm high.

The approximate size of BI would've been known before they moved away from the 1942 location - the navcams were down and the pancams were targeted. So I'm guessing that the spectral info from the BI pancam sequence was important in the decision to go back.

Do the oldtimers here remember another time that they turned back to study a target? There's been backtracking due to mobility problems, but I don't recall anything like this.

To add to my post above, the BI pancam sequence only came down late Saturday. The sol 1950 drive was Sunday. So it would make sense that they didn't turn back till 1952 if the pancam sequence was the trigger.

They turned Spirit back on sol 454 when the layering at Methuselah was spotted while Spirit was attempting to drive up Husband Hill. Spirit then spent an additional two month's there.


http://marsrovers.jpl.nasa.gov/newsroom/pr.../20050524a.html


Methuselah:
http://marswatch.astro.cornell.edu/pancam_...selah_new2.html

Is this the one?
Click to view attachment
From hortonheardawho

There was talk of heading back to Erebus after leaving Victoria. At the same time, the talk was of studying cobbles out on the plain. I wonder if some on the team wished they had taken a closer look at that "erratic boulder" which looked like the Mother of All Cobbles to me.

Thanks for finding that. That was viewed from the Olympia site. You can see from this image that it's maybe more of a rubble pile than a boulder:
http://marsrovers.jpl.nasa.gov/gallery/all...KCP2283L7M1.JPG
I get around 40 by 17 cm size for it, so BI is a fair bit bigger.

I think the only other time was for Paso Robles. But that was a short hop.

That's right, so far:

Could it be Alvin was a target near the crater? Here they seem to refer to that crater as "Kaiko."

Yeah, I guess it is; but it appeared several times larger in my memory.

Drksywxlt, yes, the rovers have been sent on some seemingly roundabout routes to avoid bad ground, esp. since Oppy got stuck for several weeks in a sand dune. If there is one thing we have learned here at UMSF, it's that the rover team knows what it is doing.

I guess in the category of 'turn back to go somewhere' - the traverse of the northern rim of Victoria, only to enter at the very point we arrived must count But there was a very good reason for that.

Yep, and that... the rovers don't

Mmm, strange...
There were two pancam shots taken at that site, the first named Alvin pointing to the crater at the NW (right) and the second named Dolphin pointing to another one at the WSW (left). Here's an MMB snapshot with the images in context.
Click to view attachment

01950::p2385::20::9::0::0::9::1::19::pancam_Alvin_L257
01950::p2386::20::3::0::0::3::1::7::pancam_Dolphin_L257

So, perhaps it should be named Alvin/Kaiko; both are vessels used in deep sea exploration.

Another interesting note in the latest status report: "As of Sol 1952 (July 21, 2009), Opportunity's solar array energy production was 493 watt-hours with an atmospheric opacity (tau) of 0.462 and a dust factor of 0.559."

That's an almost 20% boost in energy production compared to the previous week (414 Whr).

The crater namers forgot that they had already used the name Alvin. Check out the very first post in the Opportunity Route Map thread many years ago... So they had to re-name the crater.

Phil

Thanks for the info, Phil.

Time for another map update...

Here's our target "Block Island" in sight some 20m to the south.
We might get there in one driving sol and in position for IDD work in two more.
Click to view attachment

Two foreign forms on a sand ribbed plain

One low entropy
The other high

One moves
The other still

One itinerant
The other resident

One seeks
The other found

The seeker approaches

Land - well, something interesting - ho..!

Click to view attachment

Click to view attachment

At this distance and angle, my mind is turning that object into a tiny boat being tossed about in the waves.

What are those Crab Fishermen from The Deadliest Catch doing here on Mars?

Are they trying to catch cobbles of crabs here?

SFJCody, your poem is clever and elegant. It calls to mind this one:


Ozymandias
Percy Bysshe Shelley

I met a traveller from an antique land
Who said: "Two vast and trunkless legs of stone
Stand in the desert. Near them on the sand,
Half sunk, a shattered visage lies, whose frown
And wrinkled lip and sneer of cold command
Tell that its sculptor well those passions read
Which yet survive, stamped on these lifeless things,
The hand that mocked them and the heart that fed.
And on the pedestal these words appear:
`My name is Ozymandias, King of Kings:
Look on my works, ye mighty, and despair!'
Nothing beside remains. Round the decay
Of that colossal wreck, boundless and bare,
The lone and level sands stretch far away".


Hope I am not duplicating the work of someone else who has been inspired by the Meridiani landscape to post this poem . . . (and Stu -- haven't digested your longer poem yet -- but to whom does "The hand that mocked them and the heart that fed" refer to, ie, can you diagram that sentence?)

And a related analog is, of course, the Rosetta Stone -- which is black -- and Block Island may prove to be a geological Rosetta Stone.

The latest traverse map looks puzzling. Does this mean the Oppy team have now abandoned going West and will resume a route to the South?

Or is there some other reason for the U turn?

Go back to post 43 of this thread and read on from there.

Yes, the reason is to go back for a look at the rock, Block Island.