From TPS's April 30, 2008 Rover Report, Steve Squyres says:




As a "Big Crater" fan, I'm excited to hear these words!

Of course that is either a mis-quote or a slip by Steve, the Mini-TES is both inoperable and not located on the IDD (which was what Steve was talking about at the time)

Listening SS on the TPS interview I've realized that we can now say that the size of the lake/sea at Meridiani was at least 6 km big in the direction Endurance-Victoria. SS said that they've found basicaly the same stuff in both crater.
So, one advantage, getting to Ithaca, will be to extend this ground proof both in a second dimension and in size.

Given Oppy's demonstrated progress on getting to a cliff face a few meters away, does anyone still believe Ithaca is a realistic goal? Something always happens to interfere with those hoped for 100m a day drives. It's a given. Both Oppy and Spirit have given us their "miracle miles" by getting to Victoria and the summit of Husband Hill. I don't hold out hope for any more. It's basic neighbourhood poking around from here till the end, IMO.

Brian

I'm with you, Brian - with regards to the rovers I can't help feeling that "old car feeling" you get when, a few years into car ownership, once the novelty and the new smell have long worn off, and the odometer has passed the 100k miles mark, you find that the central locking starts gumming up, bulbs pop with increasing frequency, and there's a mysterious rattle which only occurs on cold mornings.

I love the rovers to pieces, but surely we're at the point where we'd just about trust them on a trip to the shops but not an 80mph burn down the M6...

Andy

Don't forget we're sitting on a sandy, 20 degree slope at the moment! I'm sure Oppy could manage a few more "burns down the motorway" once we get out onto the smooth, flat annulus outside Victoria...

It doesn't always mean the end...my car is a few miles short of 200,000, and until it needs something big beyond routine maintenance, I see no point in replacing it. I hope Oppy and Spirit have its longevity.

I'm with you Ted.

Climber - "Basically the same stuff" in both craters does not mean there was a lake/sea there, because the sediments are clearly not lake or sea beds. They are cross-bedded, obviously transported sediments, derived from some place else via either wind transport (according to SS et al.) or via impact reworking (according to Knauth et al.).

Regarding the later discussion, I still drive (and abuse) a 1985 4WD pickup truck with its original engine and transmission. It had 7 years and 100 k+ miles on it when I bought it. I love that go-anywhere vehicle, even though it has developed some obvious quirks and rattles with age. So don't write 4-year old Oppy off yet.

-- HDP Don

Thanks for your correction Don. I thought I understood this from SS interview but I understand now that I was wrong.

Re "old vehicules", Oppy's even a 6WD and I'm gald your "on board" for the BIG drive

I think SS was not just referring to the extent of transported sediment deposits. He was also referring to the extent of ground water action upon those deposits.

That remains to be demonstrated, IMHO. Certainly near both craters (Endurance and Victoria, and all across Meridiani Planum, based on orbital images) there is a salty high-albedo layer (efflorescence-like?) near the surface, beneath a lag deposit of "gray" hematitic spherules. This more likely demonstrates a long-lived wind erosion/evaporation/frost leaching/weathering surface rather than a particular hypothetical groundwater table. There are tiny spherules in some layers at both sites (and in a particular layer stratigraphically beneath Home Plate in Gusev Crater) - again, not necessarily owing to groundwater, if the spherules formed via impact explosions and steam condensation (volcanic explosions and steam condensation have been interpreted by SS et al. as forming Gusev spherules). Everything is cross-bedded, mainly at low angles, which feature might be expected via either the wind/water or impact surge hypothesis, but the layers have not been correlated, and nearly identical cross-bedding is exposed in Home Plate in Gusev Crater (albeit interpreted as caused by volcanic steam explosions, with possibly a late wind contribution). Although some festoon-like features have been noted here at UMSF in the middle of Victoria Cliff exposures, none have been officially remarked upon, AFAIK - in fact, the interpretation has been made that that the sections do not correlate, because the Endurance section (with larger spherules and the alleged festoons) must lie buried beneath the section exposed around the rim of Victoria. This section has been interpreted as entirely eolian (wind-deposited), despite its apparent "festoons". Impact excavation (i.e., impact reworking) is interpreted to have dug up the large spherules seen around the rim of Victoria. Of course, we interpret the bedding features too (in fact, all exposures studied by both rovers) as possibly representing impact reworking, on a very much larger scale, with much participation of water, on both sides of Mars, but that is definitely not the official story of SS et al. (at least, not yet ).

And so on. Considerable confusion, some inconsistencies, but apparently not (AFAIK) a demonstrated stratigraphic correlation Endurance Crater to Victoria Crater, except in a very general way. Not wishing to repeat old arguments, I'll leave it at that.

-- HDP Don

Please do. We have been through this at significant length before.

Although I was the one who originally suggested the possibility of festoons in Victoria exposures, I am now convinced there are none here. If the MER team thought they saw any, you can be sure they would have made detailed observations of the suspects. Lacking a stratigraphic succession similar to that observed in the Eagle, Endurance, and Erebus sections, it would be difficult to suggest anything more than a very general stratigraphic correlation between the northern and southern observed sections.

There are still the geochemical/diagenetic contacts to consider. There is no reason to assume that they would be parallel to the stratigraphic contacts.

This robotic geologic exploration is fascinating, is it not? I must suspect that a human geologist in the field on Mars would have resolved many of these questions in a day or two.

Yes but, but, but, 2 human geologists would have resolved them in 2 completely different ways! And what about a committee of 30 reward-seeking "experts" constantly jostling one another at the outcrop? You can convince yourself of whatever you need to, and so can I, and so could Lowell, and so can a committee or a jury or the US Congress, but that doesn't make the result a "resolution" in the scientific sense. Knowing that, I try to convince myself of absolutely nothing (and not to allow anyone else to convince me of anything), and then I explore what is demanded by actual observations, logic, and Occam's razor. That doesn't mean that I'm necessarily right - only that I'm a scientist.

-- HDP Don