2. A Wealth of Opportunities The signature of water is pervasive in and around the proposed ellipse, which resides ~600 km ENE of Opportunity –Ellipse: Over a dozen diverse layers rich in sulfates/hydrated minerals are seen from orbit Many small craters have excavated underlying material in this flat, navigable site. –Beyond the Ellipse: Large water-related features MSL is well-equipped to assess this potential habitat for past life and it can answer many questions raised from the Opportunity Rover data.

3. There was extensive fluvial erosion in this region of ancient Mars (maybe that’s why so many interesting things are exposed here?). Valley networks were forming before and after the Meridiani deposits. Bottom line: water was important here! MOLA topography (pole-to-pole slope removed) Hynek and Phillips, 2001

4. Hynek et al., 2002 Light toned, differentially eroded “etched” terrain was identified outcropping from under the hematite- bearing unit. The unit was noted for the “many complex strata contained within” > 500-m-thick unit is both high in albedo and thermal inertia. Opportunity

5. More recent mapping shows the extent of etched terrain well beyond the hematite plain = >3.3 × 10 5 km 2 200 km 0 THEMIS thermal inertia Hynek, 2004 proposed ellipse 0200 km sulfate-richsulfate-rich ESA’s OMEGA instrument shows a strong sulfate/hydrated mineral signal from the etched unit (Gendrin et al., 2005; Arvidson et al., 2005)

6. 200 km 0 Zooming In

7. Ellipse is within a >200-km-long exposure of layered sulfate-rich bedrocks. hematite-bearing unit THEMIS Day IR mosaic credit: ASU etched unit Many alternate ellipses exist that are safe and scientifically interesting.

8. Ellipse Characteristics Center: 0.0° N, 3.7°E Elevation: -1.29 km (1σ = 64 m) Max Slopes: 5 km=0.9°; 2 km=1.7°; MOLA shot-to-shot average of ~1° IRTM Rock Abundance: ~7% Thermal Inertia: 350-550 J m -2 K -1 s -1/2 Albedo: 0.19-0.21 Dust Index: Steve Ruff says it’s great. Winds: Scot Rafkin says a-okay! 30 m contours THEMIS VIS and MOC NA with MOLA colors

9. Ellipse Characteristics Immediate science return. –ANYWHERE you land will have interesting mineralogy and diverse stratigraphy. A number of small craters have excavated underlying material. 30 m contours THEMIS VIS and MOC NA with MOLA colors

10. Ellipse Characteristics Many distinct, sulfate rich layers outcrop. A number of small craters have excavated underlying material. Center: 0° N, 3.7°E Elevation: -1.29 km (1σ = 64 m) Max Slopes: 5 km=0.9°; 2 km=1.7°; MOLA shot-to-shot average of ~1° IRTM Rock Abundance: ~7% Thermal Inertia: 350-550 J m -2 K -1 s -1/2 Albedo: 0.19-0.21 30 m contours THEMIS VIS and MOC NA with MOLA colors A A’ A The diverse layers suggest a changing depositional environment and/or varying degrees of aqueous alteration.

11. V1 V2 MPF Sp Op MSL Mellon et al., 2000 An unexplored region

12. Regional Water-Related Features MOC NA E1600368

13. A diverse navigable surface A number of craters to study Lack of aeolian features layer contacts in MOC NA 1 km

14. Eastern Meridiani Rationale The Opportunity Rover has examined an upper section of >500 m of ancient sulfate-rich layers. –While the mission changed our view of the planet, many questions remain about the amount and role of water. Eastern Meridiani allows access to the heart of this section and MSL has the instruments to address the history of water. –Many immediately accessible, diverse layers are seen in and around the safe and navigable ellipse. –There’s the opportunity to link 2 landed data sets to the orbital context. –Large-scale water-related features reside in and immediately beyond the ellipse. 1 Landing MSL is this region would accomplish the overriding mission goal by assessing a habitable environment with a water-rich history.

15. Diverse, Ancient Sedimentary Outcrops and Water-Related Features Abound