MSL landing sites Options

[tuvas]

As there are some pictures being released from HiRISE of proposed MSL landing sites, I thought I'd give you what little I know about the process. As of the HiRISE team meeting a month ago or so, there were about 40 proposed sites to land MSL. These sites were prioritized, and are being photographed roughly in priority order. Each site requires a picture from each of the 3 main cameras (CTX, CRISM, and HiRISE) in their highest resolution in order to proceed. If it's determined that there can be a safe landing site, as well as interesting science targets, then they will advance to the next level, where I presume they will "wallpaper" the areas with HiRISE and CRISM (CTX, well, they get the whole landing ellipse in one shot, I think...). They likely will also photograph science areas near the proposed sites to look for interesting targets. After that, well, your guess is as good as mine. Note that none of this is official, but it's what I would expect. Also note that the landing site selection is still opened to new suggestions, the ones they have so far are not a complete list. The priority also doesn't mean anything right now other than they are the targets which will be photographed first, these priorities are still subject to change. But, well, I thought I'd send this out there for you all sink your teeth on, it really is quite interesting!

[edstrick]

Considering that a mission requirement for MSL is kilometers, with ?tens? of km planned for post primary misison operations, the overriding secondary requirement for a site is accessible diversity. Yeah, that's a contradiction in terms. The overriding primary requirement is to target geology made of materials of biological and/or origins-of-life significance. There is a preliminary consensus that materials LIKE the phyllosilicate bearing terrains are top candidates.

To a certain extent, Meridiani sulfate dune deposits are "been there, done that", though we would learn much more from a revisit with new instrumentation. But there are other, vastly more complicated, exposures of Meridiani layered deposits, some in spectacular "etched" badlands in the central part and north-east parts of Meridiani Sinus (the old albedo feature.. the split in the Sinus: "Dawes Forked Bay" is actually an Earth-observable patch of high albedo badlands.

Oppy's Meridiani plains are geologically boring on the level of "if you've seen several stratigraphic sections, you've seen them all" Victoria will let us go deeper stratigraphically than Endurance, but all the evidence so far is that it's "more of the same with variations". The landing site was ideal for Opportunity, especially with it's extended treks to Endurance, the etched terrain, Erebus and Victoria, but the MSL rover would probably need to go 100 km or some large amount to get to dramatically different materials, if it was landed in Eagle crater.

Spirit was lucky. The basalt plain on the floor of Gusev was a near-disaster, though we would still have learned far more about martian surficial geology in lava plains than we learned from Vikings and Pathfinder. The pure luck in landing close enough to the uber-diverse geology of the Columbia hills made all the difference in the mission.

A "Best" landing site for MSL will be more like Gusev than Meridiani -- We will go to check out a primary mission objective set of geologic formations and materials, but we will want to have the maximum possible "go to" diversity of geologic materials of diverse geologic ages, once we've checked out and worked over the primary target. The more utterly distinct the accessible terrains, and the more different in ages the materials they can reach, the more transforming MSL will be to what we know of Mars, compared with what we will know from Viking/Pathfiner/MER/Phoenix. Spirit on Gusev lava plains, unable to reach older terrain, would have extended our knowledge. In the hills, it's transforming it.