Northern Sinus Meridiani Landing Sites for MSL

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Northern Sinus Meridiani Landing Sites for MSL

• K. S. Edgett and M. C. Malin
• Malin Space Science Systems

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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 (lt 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
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Picking a Site

• Theres 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)

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Approach Advocated Here

• This presentation advocates going to a site with
  diversity
• How will we know that weve addressed
  habitability unless weve looked at a lot of
  different material?
• Here, we suggest sites in the Sinus Meridiani
  region.
• We acknowledge in this case that theres 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.
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Light-toned, layered rock underlies most, if not
all of Sinus Meridiani.But vast portions of
northern Meridiani are nearly-bare rock outcrops.
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More than 800 m of stratigraphy are exposed in
Sinus Meridiani.MER-B has access to lt 1 of that
stratigraphic column.
Source Northwest Sinus Meridiani geologic sketch
map by Edgett (2005, Mars, 1, 558).
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Differing Bedding Styles, Tone, and Erosional
Expression Point to a Diversity of Materials
R16-01694
R15-02235
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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.

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Theres dozens of places where one can fit a 20
km diameter ellipse
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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 Hyneks abstract
Examples of outcrop surfaces
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Instead of recommending dozens of sites, weve
identified a top 5 (in priority order) based on
science goals.
(In addition to site suggested by Posiolova et
al.)
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The prioritization is based on a combination of
access to diversity of bedrock materials and our
perception of landing site safety, based on MOC
1.54.5 m/pixel views.
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.
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Site 1 (2.63N, 1.17W)
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
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Site 1 (some
details)
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Site 2 (1.89N, 359.72W)
E03-02133
MOC view of surface closest to ellipse center.
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 didnt have time to update it.
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Site 2 (some details)
Site 2 would be able to access areas like
this, which show considerable diversity.
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Sites 3 (2.42N, 356.58W) and 4 (3.07N,
356.80W)
site 3 center
site 4 center
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 doesnt provide access to
materials as interesting as sites 13
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Site 5 (2.35N, 353.39W)
site 5 center
Pros really cool vistas, driving among
buttes/mesas Cons materials not
particularly diverse
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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
  weve 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.