I seriously doubt it's that shallow. Based on the orbital images, there are some nice vertical cliffs there, and beyond the cliffs there are streak marks on the sandy slope leading to the center dune field. Those streaks would appear due to the material sliding toward the center of the crater, and the rough minimum angle I'm sure can be calculated based on gravity and the cohesiveness of the material.

I had already decided not to send this image I made some time ago, because I was somewhat dissatisfied with its outward appearance. But I thought it's maybe suitable to this discussion.

To have a better idea of the relative proportions of Endurance and Victoria Craters, I made a cross-eyed pair of the non-map-projected MOC images (for their better resolution) and pasted EC into VC for comparison. The yellow lines are for measuring the depth and steepness of both craters. Crater depths based on parallax measurement are given, I think they are accurate to one pixel. This means that VC (28 pix) is almost exactly three times as deep as Endurance (9 pix).

On the other hand, I think the results are rather inconclusive as to my attempt to determine the angles of various slopes (decimals = depth parallax divided by line length). There's quite large error marginal due to many uncertainties. But I'm quite sure that at least the West Ramp is gentler sloping than the SW ramp of Endurance, so no difficulty for Oppy going in and coming out, IMO.

Yes Pando, I'm agree with you. I think that the crater is deeper than the known MOLA datas. To have sand sliding from the rim to the center, it must have an inclination more important. And the shadows of the cliffs might significate that there is a good depth.

Thanks marswiggle, this is exactly the check I was looking for...
I do not recall the Endurence depth (perhaps something like 30m?) but, even if with uncertains you mentioned, yours and Pando's considerations assure that we aren't going to see an "enlarged Erebus"!

Well - Endurance was almost 16m deep according to the published DEM

I'm expecting Victoria to be somewhere between 35 and 45m deep - just guessing.

Doug

That sounds like a good guestimate. I searched for "official" comments about Victoria and my searches did turn up one Leonard David article that I did not remember seeing, though it apparently was published twice on space.com and another time on MSNBC in May and June. It had a couple of comments from Steve Squyres and William Farrand that are relevant to recent discussions.

http://www.space.com/missionlaunches/06051...ers_update.html

Steve commented on the initial campaign after arrival at Victoria:
"Once there, Squyres said that the plan is to approach that feature much as they did Endurance Crater.
“[We’ll] start by taking images from several points along the rim to get the lay of the land…and then see if there’s a place where we can enter the crater safely,” Squyres said. “There’s no guarantee that we’ll be able to get in, of course, but we’re not driving all this way just for the view.”"

William Farrand compared the outcrops at Eagle and Endurance to what they expected to find in Victoria:
"“We got about 40 to 50 centimeters of outcrop at Eagle Crater [at the start of its roving] and then 7 meters at Endurance Crater.”
However, at Victoria, it looks like there’s a deeper story there.
Images taken from Mars orbit suggest there might be something like 65 feet (20 meters) of outcrop exposed within the walls of Victoria Crater, Farrand stated."

Of course, once we get there and see what things really look like, plans could change.
...edited to put Leonard David's names in the correct order...

FWIW, here is a photo of Barringer Crater shortened vertically to give the diameter:depth ratio that we may see at Victoria (from 7:1 to about 20:1). This may be close to what it could look like. Maybe...

--Bill

Wow, thats a dramatic difference from the real Barringer: ca. 1200 m x 170 m

Endurance is ca. 130 m x 20 m

looks like you are estimating Victoria at ca. 800 m x ca. 40 m

I hope you are right and I am wrong.

My non-geologist hunch is its steeper and deeper. Closer to ca. 800 m x ca. 90-100 m.

steeper and deeper while more visually dramatic would also be treacherous. I hope they will try to enter somewhere rather than first circumnavigating completely

soon we'll know

ken

The discussion of Victoria's depth and geology (with limited data) is fascinating - maybe a good subject for a new thread.

Doing a quick and dirty calculation using a d/D ratio of 1:8 you'd realistically expect a maximum depth of 100m for this crater. It looks as though there is considerable infill in Victoria however and a thick mantle of dust lies over the original crater floor. The current depth would probably be on the order of 75m I'd say (from high point of rim to the drift base in the centre of the crater). I'm guessing that where the model is accurate is in how wide and flat the centre of the crater will appear. But I think the edges will be much steeper than the model suggests.

If the solar phase angle in the photo of Victoria is known, just take the sine of that and multiply by the width of the shadows at the cliff bases and that would give you a rough idea of the height of the NW cliffs. I'd venture they are somewhere near 40 m high. That should make for an impressive sight! No money back I fear! (Ken I didn't see your post till after mine but I think you're right)

This is such an interesting crater. It is not typical of the majority of Martian craters, with its sinuous, selectively eroded NW rim, its crenellated southern exposure towering high above the apron (probably visible from a good distance to the SE just like Endurance was from Eagle), and the gorgeous drifts at the base. I've also been fascinated with the dark streaks of dust on the apron to the NE that seem to have been winnowed from the "chaff" or heavier dust and channelled up through the eroded bays in the crater rim. Why would this be so distinct from the surrounding dust? Perhaps as dust settles in the bottom of Victoria it also separates gradually with the lighter, dark dust rising to the top and the heavier settling into the dunes. That's something I hope they will check into while circumnavigating Victoria.

Like everyone, I can hardly wait for that first photo! I haven't posted much but am really enjoying the forums. Thanks for the contributions.

For Barringer I'm using 4100' x 570' and for Victoria 700' x 35' (but depth values are all over the map), so I took a recent bottom-end of the range. If Victoria is 100m deep, then it will resemble the un-shrunk Barringer.

Your WAG is as good as mine...

But I suspect that Victoria will be shallow, there has been a great deal of slumping of the walls and some sand blowing in. We'll see.

The MSSS site gives Sun elevations for all images; for Image R1500822 the solar altitude is 65 degrees.

http://www.msss.com/moc_gallery/r10_r15/im...5/R1500822.html

--Bill

Steepness of some of the walls might mean some areas of the crater would be off limits due to power limitations, yes?

Another reason to peek at the crater from the rim from a variety of positions before going in, so as to visibly mark where the shadows fall? I mean, with a smooth rim, that's one thing, but could you see parking close to a part of the rim that juts out?

Ah yes, that first photo... How many times have we waited, poised on the edge of our seats for that next, amazing and anticipated view, as each of these intrepid rovers has carried us armchair explorers to new Martian vistas time and time again. I suspect each of them still have a few surprises in store for us. There is probably an entire book waiting to be written, describing those special instances.

Since Victoria is supposed to be a crater exhumed from a previously buried past, I am not sure how useful canned depth/diameter ratios will be, but my gut feeling is that such ratios will be smaller rather than larger in this case. Looking at the MOC stereo pairs, it seems to be pretty deep, but in those same pairs, so does Eagle crater. The one thing I feel fairly confident about is that it will probably be the most impressive vista Opportunity captures during it's entire lifetime. But I do look forward to a later view resembling that at Burns Cliff.

MarkL: Welcome. You've described several of the questions we've been debating for a while, now. The next impressive vista is within our reach. (Somehow, it seems that that wheel should be turning the other way.)

I did this already.
The shadows indicate that the "cliffs" around the edge are 8m+-2m high. How much deeper the interior is I can't say but I'm sticking with an overall depth of 20-25m for now. I really do hope to be wrong though.

CosmicRocker,

Can you expand on why you think this is true? Is there evidence that the evaporites or some other formation were once deposited over the top of VC and then eroded away? Of course there must have been some erosion since VC was formed, but is it possible that VC is younger than the evaporites and hasn't seen much "exhumation from a previously buried past"?

Forgive me if this has already been discussed in another thread. I'm afraid I don't have time to do a full search.

Thanks,

Castor

We're getting sooo spoiled...Even it is only 25 meters deep it will be astounding, I just put Oppy to scale with a 25 and 75 meters deepness...

http://i16.photobucket.com/albums/b14/ustrax3/howdeep.jpg