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Exploration
Geography of Curiosity Landing Site
Image Credit: NASA/JPL-Caltech This is to appreciate the accuracy of MSL landing
Gale Crater Image Credit: NASA/JPL-CalTech/Cornell/ASU Curiosity precisely landed at the foot of Mount Sharp: X (red) 4,59° Lat. South. The crater is 154 km wide and Mount Sharpt summit is 5 km above the bottom of the crater. Atop the landing site, you see the canyon winding its way into the mountain. Its path will be used by Curiosity to climb the slope.
Now that we know where Curiosity landed, we may consider the next step: the exploration of the Gale crater. To give you some background, I selected two notes from NASA and I completed them by some information on the geology of the place. Enjoy! http://www.nasa.gov/mission_pages/msl/multimedia/pia15690.html http://phys.org/news/2012-03-mount-sharp-mars-links-geology.html Pierre Brisson
(Doc. NASA/Milliken/Anderson and Bell/Ryan Anderson) The landing site of Curiosity is at the bottom of the letter "C" (in black, at the lower limit of the "High Thermal Inertia" zone)
Gale ChoiceSome Geology : Meeting our highest expectations Curiosity landed near the middle of the ellipse where it was supposed to land, at the nearest of the path that should allow it to explore the different geological layers of Mount Sharp. To begin with, the landing area i.e. the bottom of the crater will be interesting to study because, whatever the nature of the rock, it obviously went through a wet period. Curiosity may begin its exploration by going in the opposite direction of the Mount where it could scrutinize an alluvial fan from the crater rim (some twenty km away). Then, turning around to go the other way, it will enter an area that, seen from the Mars orbiters, appears very dark. They are sand dunes of mafic material. Some light materials are striking across them. It is also sand but most likely coming from the hydrated rocks of the lower layers of the Mount (see below). Apart from the chemical interest of those sands, the pattern of the dunes will also tell about the wind conditions and wind strength in the area. According to the nature and the shape of sand particles, NASA will this be able to evaluate its abrasive power. About 4km southwards, going further towards Mount Sharp, Curiosity will begin climbing the slope, taking the opportunity of a canyon winding into the mountain. This will facilitate its progress and allow an easier study of the deepest geological layers which will appear on the wall of the canyon. These are, at the beginning of the ascent, the most interesting since they are clay rich (sedimentary rocks which formed in liquid water). Later on, higher in the mountain, going from the earliest geological period, called Noachian (or Phyllosian) to the Hesperian (or Theiikian), the rover will encounter sulfates (hydrated rocks formed under a sulfur rich atmosphere, water percolating from the underground).The highest strata should be less interesting as belonging to more recent times when water had only an episodic role in an extremely scant atmosphere. NB: “Phyllosian” (ie phyllosilicates era) which refers to the presence of clays and Théiikian (sulfates era) are names with geological connotation alternatively proposed by Professor Jean-Pierre Bibring (Paris Institut d’astrophysique Spatiale)from the data collected by the ESA MarsExpress orbiter, as an alternative to Noachian and Hesperian . The geological eras do not overlap exactly the “old” ones coming from craters counting. Those proposed by Jean-Pierre Bibring are shorter (Phyllosian goes from the origin till the LHB (Late Heavy Bombardment) i.e. about -4 billion years, and Theeikian covers the period during which the emissions of sulfur in the atmosphere, from volcanism, were the most abundant, ie until -3.75 billion years (against -3.5 billion years for the Hesperian). Pierre Brisson
InSight Explore Gale with Curiosity Mars 2020