Mars Science Laboratory 1st Landing Site Workshop Pasadena, CA — 31 May – 2 June Northern Sinus Meridiani Landing Sites for MSL K. S. Edgett and M. C. Malin Malin Space Science Systems

Mars Science Laboratory 1st Landing Site Workshop Pasadena, CA — 31 May – 2 June Finding Landing Sites for MSL While MSL opens up many more potential places to put a landing ellipse (relative to MER and previous landers), it should be understood that MSL does not actually open up the chance of landing at some of the most interesting or scientifically crucial locations, such as –gullies (precluded by planetary protection and ellipse size) –west Candor (amazing layered rock exposures; need smaller (< 1 km) ellipses) –Eberswalde delta (critical “follow the water” site; need smaller ellipses) –southwest Melas streambeds, inverted streams, fans (key “follow the water” site; too rugged) –polar caps (outside the latitude range) west Candor, 3km wide

Mars Science Laboratory 1st Landing Site Workshop Pasadena, CA — 31 May – 2 June Picking a Site There’s basically 4 ways to pick a landing site; in some locations one or more of these might converge: –Hypothesis Test MER-A (that Gusev Crater was a lake) MPL (that ice is/was present in polar layered deposits) PHX (that ice is today present within upper meter of surface) –Mineralogical “beacon” MER-B (hematite a clue that water was once present) –Geomorphic “beacon” VL-1 (floods from Maja Valles might mean site was once wet) VL-2 (northern plains/proximity to seasonal frost) –Variety of materials increase odds of finding what we seek MPF (“grab bag” idea that many rock types would be found)

Mars Science Laboratory 1st Landing Site Workshop Pasadena, CA — 31 May – 2 June Approach Advocated Here This presentation advocates going to a site with diversity: –How will we know that we’ve addressed “habitability” unless we’ve looked at a lot of different material? –Here, we suggest sites in the Sinus Meridiani region. –We acknowledge in this case that there’s no specific hypothesis to test; that the existing discussion of these materials in the present scientific literature inadequately addresses questions concerning depositional setting and rock types for the materials. Send MSL to a site that offers a diverse suite of materials, any of which have potential to yield results on habitability.

Mars Science Laboratory 1st Landing Site Workshop Pasadena, CA — 31 May – 2 June Light-toned, layered rock underlies most, if not all of Sinus Meridiani. But vast portions of northern Meridiani are nearly-bare rock outcrops.

Mars Science Laboratory 1st Landing Site Workshop Pasadena, CA — 31 May – 2 June More than 800 m of stratigraphy are exposed in Sinus Meridiani. MER-B has access to < 1% of that stratigraphic column. Source: Northwest Sinus Meridiani geologic sketch map by Edgett (2005, Mars, 1, 5– 58).

Mars Science Laboratory 1st Landing Site Workshop Pasadena, CA — 31 May – 2 June Differing Bedding Styles, Tone, and Erosional Expression Point to a Diversity of Materials R R

Mars Science Laboratory 1st Landing Site Workshop Pasadena, CA — 31 May – 2 June What Are The Materials? Literature is sparse and incomplete relative to the importance of these outcrops, which cover an area greater than the Colorado Plateau. Most suggest water was involved, either in depositional setting, diagenesis (groundwater), or both. Some suggest the rocks are sedimentary, others suggest tephra (primary volcanic ash). –“sedimentary” may include eolian, lacustrine, marine, and impact ejecta OMEGA results suggest some rocks contain sulfates and/or bound water. Some rocks, we know, contain sand/granule-sized hematitic concretions, others either do not, or have much smaller concretions such that they cannot form an eolian lag.

Mars Science Laboratory 1st Landing Site Workshop Pasadena, CA — 31 May – 2 June There’s dozens of places where one can fit a 20 km diameter ellipse…

Mars Science Laboratory 1st Landing Site Workshop Pasadena, CA — 31 May – 2 June …but they all have to be “go-to” sites because the terrain on the outcrop areas is very rugged, and the terrain of Meridiani Planum, as we know from MER-B, does not provide access to the diversity we know is there. site in Hynek’s abstract Examples of outcrop surfaces

Mars Science Laboratory 1st Landing Site Workshop Pasadena, CA — 31 May – 2 June Instead of recommending dozens of sites, we’ve identified a top 5* (in priority order) based on science goals. *(In addition to site suggested by Posiolova et al.)

Mars Science Laboratory 1st Landing Site Workshop Pasadena, CA — 31 May – 2 June The prioritization is based on a combination of access to diversity of bedrock materials and our perception of landing site safety, based on MOC 1.5–4.5 m/pixel views. PriorityEllipse Center*Elevation Rectangular Region of Interest* ellipse + outcrops MSL would access °N, 1.17°W (2.60°N, °E) –1.6 km 2.25°N, 0.98°W °N, 1.47°W °N, 0.98°W °N, 1.47°W (2.22°N, °E °N, °E °N, °E °N, °E) °N, °W (1.87°N, 0.37°E) –1.4 km 1.38°N, °W °N, 0.12°W °N, °W °N, 0.12°W (1.36°N, 0.63°E °N, °E °N, 0.63°E °N, °E) °N, °W (2.40°N, 3.51°E) –1.5 km 2.02°N, °W °N, °W °N, °W °N, °W (2.00°N, 3.86°E °N, 3.18°E °N, 3.86°E °N, 3.18°E) °N, °W (3.04°N, 3.29°E) –1.4 km 2.72°N, °W °N, °W °N, °W °N, °W (2.69°N, 3.72°E °N, 3.10°E °N, 3.72°E °N, 3.10°E) °N, °W (2.32°N, 6.70°E) –1.1 km 2.06°N, °W °N, °W °N, °W °N, °W (2.04°N, 6.87°E °N, 6.29°E °N, 6.87°E °N, 6.29°E) *East coordinates are approximately IAU 2000 aerocentric latitude/east-positive longitude (used for targeting by ODY THEMIS, MRO HiRISE, and MRO CRISM), but it is possible the conversion is a bit in error, so buyer beware. The west coordinates are consistent with all previous Mars mapping (for over a century) and are the planetographic latitude / west-positive longitudes used in 1990s-era map products and used for MGS MOC (with high success) and MRO CTX targeting.

Mars Science Laboratory 1st Landing Site Workshop Pasadena, CA — 31 May – 2 June Site 1 (2.63°N, 1.17°W) MOC view of surface closest to ellipse center. Pros: diversity of layered material, particularly if rover drives south surface generally looks as safe or safer than MER-B ellipse Cons: a few buttes near ellipse center could be EDL hazard to date, has poorest MOC NA coverage of the 5 sites

Mars Science Laboratory 1st Landing Site Workshop Pasadena, CA — 31 May – 2 June Site 1 (some details)

Mars Science Laboratory 1st Landing Site Workshop Pasadena, CA — 31 May – 2 June Site 2 (1.89°N, °W) Pros: possibly greatest diversity of layered material in smallest area central part of ellipse resembles MER-B site in terms of EDL safety Cons: outer edges of ellipse are rugged Note: The area is completely covered by MOC narrow angle images. Shown here is an older mosaic; I didn’t have time to update it. MOC view of surface closest to ellipse center. E

Mars Science Laboratory 1st Landing Site Workshop Pasadena, CA — 31 May – 2 June Site 2 (some details) Site 2: would be able to access areas like this, which show considerable diversity.

Mars Science Laboratory 1st Landing Site Workshop Pasadena, CA — 31 May – 2 June Sites 3 (2.42°N, °W) and 4 (3.07°N, °W) Pros: diversity of material and erosional expression of material site 3 access to exhumed crater with finely-layered fill Cons: site 3 ellipse might be too large relative to hazards at edge of ellipse site 4 ellipse doesn’t provide access to materials as interesting as sites 1–3 site 3 centersite 4 center

Mars Science Laboratory 1st Landing Site Workshop Pasadena, CA — 31 May – 2 June Site 5 (2.35°N, °W) Pros: really cool vistas, driving among buttes/mesas Cons: materials not particularly diverse site 5 center

Mars Science Laboratory 1st Landing Site Workshop Pasadena, CA — 31 May – 2 June Summary We consider that the greater the diversity of material MSL can get to and examine, more we can say we have characterized “habitability” of Mars. Landing in northern Sinus Meridiani at one of 5 suggested “go-to” sites would provide access to a greater diversity of materials (based on erosional expression, bedding style, etc.) than accessible to MER-B. The rocks are lower in the stratigraphic column than rocks at the MER-B site; all may have been subjected to diagenesis in groundwater. All sites are equatorial and at elevation around –1.5 km. All sites are likely sandy, like MER-B site, but we’ve not looked in detail at thermophysical properties; there very few large ripple-like features (like those that MER-B has been driving among for the past year) except maybe sites 2 and 3. Details of rover trafficability and specific traverse options from the ellipses into the rugged outcrop areas still need to be examined.