Just checked the PCDT web and found some familiar names all related to "Santa Catarina", the rock currently under IDD study. "Joaçaba", "Tubarao", "Florianopolis", "Xanxerê" for the time being, all of them are names of cities in the brazilian state of "Santa Catarina".

Ah, old memories...

I was asking SS if, as, in my oppinion, Oppy is covering the ground faster than I expected, is the possibility of a total circumnavigation of Victoria closer than before?
If Oppy is going inside and (knock on wood!) not able of getting out, a full coverage of the crater from the surface would remain as a tremendous achievement...
But...nope...they're not planning on it..."Our plan is to go about 1/4 to 1/3 of the way around,
and then to go in. That could change, of course, but that's our thinking at
the moment."

Facing this I only see three possibilities of ingress: Duck Bay, Bottomless Bay or the Bay beyond Toil, that might be, reading Bergreen, Port Saint Julian...
And after ingress?
This is just a personal view, what I would like to see happening if the actual scenario persists...

That is some nasty shadowing there on that route...

There is nothing I see in Bottomless or Duck bays that other bays further round don't do as well or even better. One thing that might be crucial is how the seasonal lighting might put the rover in shadow at parts of the day when close to the larger outcrops and it may infact turn out that there's half a dozen places that are all favorable to get in, get the science and get out - but one offers systematic benefits because of slope or low shadowing. The south eastern quarter of the crater is, if the MOC DEM we've seen is to be believed, offers gentler slopes anyway - so I would think that it would be in the '3 to 5 o'clock' position that we actually go in.

Doug

I agree with the comments re the solar power constraints - it's a big risk going into Victoria at all and the last thing they'd want to be stuck with is an underpowered rover on, er, a slippery slope. That way leads to the Big Rover Trap in the centre of the pit, you know, the Sarlac wossisname.


Bob Shaw

Doug: Do you remember where you found that one? I recall a site loaded with all kinds of Mars DEMs and other stuff, but I never could locate a DEM for Meridiani or Victoria in a file format I could open.

You know, I see a lot of compelling reasons to go partially down one or more of the bays (and as close to one or more of the cliffs as possible), but few to descend all the way into the interior. After all, Oppy can make much better tangental observations of all of the bays from the rim than she could from the center of Victoria. Therefore, wouldn't it be reasonable to try to identify multiple partial entry/exit points instead of a full-blown descent?

There's only a movie of it on the JPL site somewhere...I've not found the actual DEM for that one.

Doug

There's relatively little science to be gained by Oppy going down into Victoria beyond the limits of bedrock exposure. As at Endurance, you get into the sand sheet dominated zone and traction gets seriously "iffy" long before you reach the dune field. What they'd REALLY like to do is go down one "boat ramp" and hug the side of a cape, getting a super-detailed view of layering and MiniTES spectra and X-ray/Mossbauer/Microscopic imager targets all the way down to the base of the cape. Then they'd like to "round the cape" and start up the opposite side, or traverse to the next cape's bottom and start up, repeating the super detailed stratigraphic exam in reverse.

To my way of thinking, the logical entry point would be the ramp that affords the most layers of accessible bedrock for examination. From a practical standpoint, this exposed bedrock should be the driving surface, as it was at Endurance. It might prove possible to access the layers on the sides of the cape beside the ramp, if the terrain allowed it to move within arm's reach. However, I think driving on a sandy ramp would be problematic, and my impression of the southern accesses that provide a more favourable sun angle is that they are sand covered. Plus more dunes at the rim. I also don't see the point of risking more than one entry unless no one ramp affords a total picture of the layers they would like to examine. The ultimate goal is to get in AND get out and do more exploring.

I still like Bottomless as the entry point, if sun exposure and power levels permit.

Brian

Anyone know how the Mossbauer is holding up? It's waaaaaaay past warranty, like all else...

Bob Shaw

Both mossbauers are working fine... the shortish half-life isotope sources are getting decidedly "tired", but that doesn't degrade data quality, you just have to integrate on-target several times longer than on Sol 1 to get the same signal-to-noise level.

Via Nasawatch live blog:

"Opportunity is doing great in terms of power - 600 watts. We are going to continue our clockwise rim traverse for a while. Not going to go all the way around. Need to put together a diagram as to how stratigraphy varies. As we go we are doing two things. Looking at alcoves for entrance/exit routes. One entrance point is at Duck bay - other at Bottomless Bay. Both may be adequate egress routes. We are also waiting for seasons to change for sun to move south so that when we enter alcoves we have enough power to do science on our way down."

Steve Squyres

The cobalt-57 in the Mossbauer has a half-life of 270.9 days, so after 3 (Earth) years it takes almost 16 times longer to get the same result as sol 1!

The Curium-244 in the APXS has a half-life of about 18 years, so it only takes about 12% longer than sol 1.

Any one know what date the seasons officially change ? Does spring on Mars start around June22 ?

Thanks.

I found the answer on the PS website.
Mars Calendar

So Spring starts 8 Feb 2007, in the Southern Hemisphere .