OK -- if we're seriously going to discuss where Oppy ought to go after Victoria, I must say I like Fred's idea of heading NW to get back onto the flat, almost-ripple-free terrain that lies beyond the northern extent of Victoria's apron. However, no matter what we do, we run into bad ripple/dune terrain trying to get to Ithaca.
I'd like to suggest a different set of targets. There are three craters of apparently wildly varying ages off to the east-northeast that would make a good site for a co-ordinated study set, which might only take a year or so of traveling to reach (assuming no further wheel malfunctions and the ability to travel 200+ meters a day on good "roads"). Here's my suggestion, overlain on Ustrax's regional map:Click to view attachment
My proposed route is in blue, here. (Pardon the crudity, I really only have MS Paint with which to work.) Granted, it's nearly as long a traverse as getting to Ithaca, but it traverses over better, far less dangerous terrain, and I see three very interesting targets sort of grouped together at the end of the journey.
The first target to be reached I have labeled A
is an old, degraded crater about 70% the size of Victoria. It has very much the size and appearance of Erebus, except that is is surrounded not by the etched terrain (which we know now is heavily covered with soft ripples), but with the flatter pavement we found near the landing site. It's an ancient crater, really just a ring of exposed evaporite rim material around a complete crater fill. But unlike Erebus, it's not covered over with obscuring layers of ripples. It seems to me that anything we could investigate at Erebus, we could likely investigate at A
Just beyond A
, a crater roughly the same size as Victoria but with a less obvious apron and without the bay-and-cape structures. Taking a close look at B
could answer some significant questions as to why Victoria has developed cape-and-bay structures, while B
hasn't -- is it due to differences in the target rock, or is it differences in the erosional process?
Finally, just past B
, we have C
, which is almost more of an albedo feature than a crater. This one *might* not even be an impact structure -- it's roughly the same size as Victoria and B
, but completely lacks a raised rim. Even when an impact structure is completely filled in this area, it leaves a ring of exposed evaporite rim deposits, but C
doesn't show any signs of that. It appears to be a sinkhole more than a crater, and seems to be a source of dark dust that is swept out of C
and up to the north-northwest. A sinkhole roughly the size of Victoria could teach us an *awful* lot about the subsurface structure of the entire region.
I find nowhere else within possible range where we can see such a diverse set of observation targets, and which can all be studied one after another with relative ease. Each has its own telltale signs of origin and history, and each appears to have undergone significantly different origins and erosional processes -- which is quite interesting, since they're all in fairly close proximity to each other. A study of all three features would, IMHO, give us a far better idea of what processes formed this entire area than looking at the very much more highly shocked remnants of the much larger impact that formed Ithaca. Each also provides variations on what we have already learned at Endurance, Erebus and Victoria, which should help us put those findings in a better regional context.
So -- not only do I see a good set of targets, I see a set of targets that are both easier to reach and at least as valuable to study as Ithaca would be.
What do y'all think?
-the other Doug